题名:铁电存储器用钛酸铋材料的第一性原理计算及电导机制分析
作者:刘芬
学位授予单位:湘潭大学
关键词:密度泛函理论;;第一性原理;;钛酸铋;;漏电流
摘要:
铁电存储器以其非挥发性(即使在电源突然断开的时候芯片仍能保存存储在其中的信息)、高写入速度、低功率消耗、低的操作电压、高重复读写能力以及优异的抗辐射等优越的性能,成为存储器领域最具发展潜力的产品。而铁电材料的选择是其实现商业化应用的关键。在铁电材料中,使用最多的是钙钛矿结构铁电如Pb(Zr_xTi_(1-x))O_3(PZT)和铋层状结构铁电如SrBi_2Ta_2O_9(SBT),但是PZT材料,它含有有毒元素铅,对环境有污染,且抗疲劳性较差;SBT材料,虽然抗疲劳性好,但是制备温度过高,很难与大rare earth magnets规模集成器件集成。因此,寻找适合铁电存储器用的新型铁电材料成为研究热点之一。
近年来,掺杂的钛酸铋材料因其无铅特性,大自发极化,低处理温度,高居里温度,以及优异的抗疲劳特性受到了人们的广泛关注。实验上,人们提出了A位掺杂、B位掺杂,以及A,B位共掺杂的方法,来提高BIT的铁电性能,并取得了一定的成效。但其掺杂的内部的机理却并不明朗。
在BIT器件的应用过程中,实验上观测到器件的漏电流比较大,成为限制它应用的一个主要因素。人们对于BIT的漏电流属性在实验和理论方面都做了研究。实验上,A,B位共掺杂的方法,被认为是改善其漏电流属性的有效方法之一。在理论方面,研究结果表明,漏电流与Bi~(3+)离子的挥发及氧空穴有关,并且材料中存在的杂质也被认为是产生漏电流的原因之一。人们也相应地提出很多的理论模型去解释实验上观测到的实验现象,但是其真正的内在机制还是存在争议。而当器件的漏电流过大时,就会影响到极化翻转的测量,严重时甚至会导致铁电存储器件的短路,导致存储失败。因此弄清BIT的电导机制,改善漏电流属性尤为重要。
本论文采用基于密度泛函理论的第一性原理方法,结合赝势投影平面波(PP-PAW)方法,针对BIT铁电体铋层状钙钛矿结构http://www.chinamagnets.biz/的总能和电子结构等物理性质系统地进行了理论研究,并取得了以下主要成果:
1)总能和电子结构的计算结果表明,BIT铁电相的稳定性主要源自于Bi_2O_2层和Bi_2Ti_3O_(10)钙钛矿层的畸变以及它们之间相互耦合作用释放出来的弛豫能;BIT产生铁电性质的主要原因是源自于B位的Ti离子和O离子之间存在强烈的杂化;而A位的Bi和O之间存在的较弱的共价杂化则进一步促进了铁电相的稳定。
2)由电荷密度和AIM理论计算的迁移电荷结果表明,BIT的结构畸变和铁电性质的主要诱导因素来源于B位Ti离子和O之间以及Bi和O之间的共价杂化作用;而B位Ti离子和O之间的共价杂化是产生畸变的主导因素。
3)将第一性原理计算得到的铁电相BIT的能带结构,与MIGS理论相结合,我们计算得到了BIT与Pt电极相接触时产生的肖特基势垒的高度,其值为1.26 eV,如此大的势垒足以抑制从金属向BIT导带的发射肖特基电流,这也就意味着在BIT的电导机制中,界面限制肖特基发射机制是不占主导地位的。
4)在实验方面,我们对提取的实验数据用界面限制肖特基发射机制公式来进行拟合,证明了我们的计算结果的正确性。而肖特基发射机制是一种最接近本征的电导机制,也说明了BIT中漏电流可以通过掺杂或改善实验条件来减小。
学位年度:2010
2012年1月30日星期一
无刷直流电机转矩脉动抑制研究
题名:无刷直流电机转矩脉动抑制研究
作者:钟柏
学位授予单位:大连理工大学
关键词:无刷直流电机;;转矩脉动;;直接转矩控制
摘要:
无刷直流电机(Brushless DC Motor, BLDC)具有结构简单、功率密度大、效率高和调速性能良好等优点,使其在工业领域得到广泛的应用。加之我国有丰富的稀土资源,大力发展无刷直流电机具有很大的优势。但由于电机本体Neodymium magnets结构和控制系统的原因,无刷直流电机具有较大的转矩脉动,限制了其在高精度等更广泛领域的应用。尤其是低速直接驱动场合,转矩脉动未经减速机构直接作用于负载,会产生很大的振动和噪声。
本文就无刷直流电机转矩脉动的原因进行了研究,在总结前人理论研究成果的基础上,把无刷直流电机的转矩脉动分为五种——齿槽效应引起的转矩脉动、非理想反电动势引起的转矩脉动、换相引起的转矩脉动、位置传感器安装精度引起的转矩脉动和PWM调制方式引起的转矩脉动。国内外很多学者针对这些原因进行过大量的研究,并根据某一种转矩脉动原因给出了相应的解决方案。每种方案都是根据相应的脉动原因所提出,所以并不能适用于其他方案。对于无刷直流电机这个整体来说,单一寻求某一种方案是不能很好解决转矩脉动,为此本文提出了无刷直流电机的直接转矩控制。
直接转矩控制作为一种先进的控制策略,已经成熟的应用于感应电机和永磁同步电机,并取得了很好的效果。无刷直流电机采用直接转矩控制,省去了复杂的矢量变换,具有较好的动态响应性能。文章通过分析无刷直流电机http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php
与感应电机和永磁同步电机的不同点,改进相应的算法,把直接转矩控制应用于无刷直流电机,并通过仿真证明了此方法的可行性。
学位年度:2010
作者:钟柏
学位授予单位:大连理工大学
关键词:无刷直流电机;;转矩脉动;;直接转矩控制
摘要:
无刷直流电机(Brushless DC Motor, BLDC)具有结构简单、功率密度大、效率高和调速性能良好等优点,使其在工业领域得到广泛的应用。加之我国有丰富的稀土资源,大力发展无刷直流电机具有很大的优势。但由于电机本体Neodymium magnets结构和控制系统的原因,无刷直流电机具有较大的转矩脉动,限制了其在高精度等更广泛领域的应用。尤其是低速直接驱动场合,转矩脉动未经减速机构直接作用于负载,会产生很大的振动和噪声。
本文就无刷直流电机转矩脉动的原因进行了研究,在总结前人理论研究成果的基础上,把无刷直流电机的转矩脉动分为五种——齿槽效应引起的转矩脉动、非理想反电动势引起的转矩脉动、换相引起的转矩脉动、位置传感器安装精度引起的转矩脉动和PWM调制方式引起的转矩脉动。国内外很多学者针对这些原因进行过大量的研究,并根据某一种转矩脉动原因给出了相应的解决方案。每种方案都是根据相应的脉动原因所提出,所以并不能适用于其他方案。对于无刷直流电机这个整体来说,单一寻求某一种方案是不能很好解决转矩脉动,为此本文提出了无刷直流电机的直接转矩控制。
直接转矩控制作为一种先进的控制策略,已经成熟的应用于感应电机和永磁同步电机,并取得了很好的效果。无刷直流电机采用直接转矩控制,省去了复杂的矢量变换,具有较好的动态响应性能。文章通过分析无刷直流电机http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php
与感应电机和永磁同步电机的不同点,改进相应的算法,把直接转矩控制应用于无刷直流电机,并通过仿真证明了此方法的可行性。
学位年度:2010
新型氟化物激光晶体Ce~（3+）:LiCaAlF_6的生长与光谱性质
题名:新型氟化物激光晶体Ce~（3+）:LiCaAlF_6的生长与光谱性质
作者:方奇术
学位授予单位:宁波大学
关键词:晶体生长;;LiCAF;;Ce:LiCAF;;坩埚下降法;;晶体加工
摘要:
近二三十年来,LiCaAlF_6晶体作为优良的可调谐激光晶体基质材料,受到国内外学者的广泛关注。至今, Ce~(3+):LiCaAlF_6晶体作为紫外可调谐晶体的晶体生长和光谱性质已被大量文献报道,证实Ce~(3+):LiCaAlF_6晶体在可调谐激光领域有着重要用途。与此同时LiCaAlF_6掺杂其它过渡或稀土离子的发光特性及闪烁、激光性能正在被越来越多研究机构探索和报道。另外一方面,优质大尺寸的LiCaAlF_6单晶具有深紫外可见高透过率、双折射效应较小,且物化性质稳定,不易潮解,在紫外窗口材料领域有着重Neodymium magnets要应用前景。但LiCaAlF_6晶体及Ce~(3+):LiCaAlF_6晶体生长技术固有难点,限制该类晶体产业实用化。该类晶体生长主要难点在于:(1)获取严格无水无氧的单一相LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料十分困难;(2)如何控制LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体生长气氛,防止晶体氧化及组分挥发;(3)晶体各向热膨胀系数相差较大,生长过程中易形成缺陷甚至开裂。本论文采取非真空密闭坩埚下降法进行LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体生长,通过设计和改进实验条件,探索出适合该单晶生长条件,获得了透明单晶,就该晶体材料的光学性能进行了测试表征。
本论文主要获得了以下结果:
(1)成功探索出合成严格无水无氧单一相的LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料的工艺。该工艺以高纯氟化物为初始原料,严格按照化学式的计量比配料,并充分混合原料。在高纯HF气氛保护下,对原料在程序控温条件下进行氟化烧结处理,合成出晶体生长所必需的无水无氧LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料。
(2)优质LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体的非真空密封坩埚下降法生长工艺。采用无水无氧LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料,致密填充在特制坩埚中,而后加入少量聚四氟乙稀粉末,进行晶体坩埚下降法生长。生长参数为:炉体温度调节于910～930oC,固液界面温度梯度30oC/cm左右,坩埚下降速率控制于0.5~1.0 mm/h,晶体生长完成后以20～50℃/h的速率缓慢降低炉体温度。成功生长无宏观缺陷的LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体样品。
(3)LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶的表征。应用XRD、紫外—可见透射光谱、红外光谱分别对生长加工后的LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶光谱性质进行表征。测试表明,LiCaAlF_6单晶吸收截止线位于深紫外区,在紫外可见光区透过率达85%以上,同时红外光谱显示,该单晶无OH-吸收带,从而证实坩埚下降法生长LiCaAlF_6单晶性能良好。Ce~(3+):LiCaAlF_6单晶表征表明266nm左右,有宽带特征吸http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php收峰Ce~(3+)宽带特征吸收峰,其红外光谱出OH-微弱吸收峰,在257,267nm波长光激发下,均可获得在290nm和310nm存在两个宽带发射峰。
(4)LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶的生长及加工工艺的改进。为降低晶体生长成品率及提高晶体生长效率,通过一炉多管或一管多坩埚进行垂直坩埚下降法生长,获得较好的晶体生长结果,为产业化批量LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶生长提供实验基础。通过对晶体性能研究和晶体加工实践总结,得出适合该类单晶加工工艺。
学位年度:2010
作者:方奇术
学位授予单位:宁波大学
关键词:晶体生长;;LiCAF;;Ce:LiCAF;;坩埚下降法;;晶体加工
摘要:
近二三十年来,LiCaAlF_6晶体作为优良的可调谐激光晶体基质材料,受到国内外学者的广泛关注。至今, Ce~(3+):LiCaAlF_6晶体作为紫外可调谐晶体的晶体生长和光谱性质已被大量文献报道,证实Ce~(3+):LiCaAlF_6晶体在可调谐激光领域有着重要用途。与此同时LiCaAlF_6掺杂其它过渡或稀土离子的发光特性及闪烁、激光性能正在被越来越多研究机构探索和报道。另外一方面,优质大尺寸的LiCaAlF_6单晶具有深紫外可见高透过率、双折射效应较小,且物化性质稳定,不易潮解,在紫外窗口材料领域有着重Neodymium magnets要应用前景。但LiCaAlF_6晶体及Ce~(3+):LiCaAlF_6晶体生长技术固有难点,限制该类晶体产业实用化。该类晶体生长主要难点在于:(1)获取严格无水无氧的单一相LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料十分困难;(2)如何控制LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体生长气氛,防止晶体氧化及组分挥发;(3)晶体各向热膨胀系数相差较大,生长过程中易形成缺陷甚至开裂。本论文采取非真空密闭坩埚下降法进行LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体生长,通过设计和改进实验条件,探索出适合该单晶生长条件,获得了透明单晶,就该晶体材料的光学性能进行了测试表征。
本论文主要获得了以下结果:
(1)成功探索出合成严格无水无氧单一相的LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料的工艺。该工艺以高纯氟化物为初始原料,严格按照化学式的计量比配料,并充分混合原料。在高纯HF气氛保护下,对原料在程序控温条件下进行氟化烧结处理,合成出晶体生长所必需的无水无氧LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料。
(2)优质LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体的非真空密封坩埚下降法生长工艺。采用无水无氧LiCaAlF_6及Ce~(3+):LiCaAlF_6多晶料,致密填充在特制坩埚中,而后加入少量聚四氟乙稀粉末,进行晶体坩埚下降法生长。生长参数为:炉体温度调节于910～930oC,固液界面温度梯度30oC/cm左右,坩埚下降速率控制于0.5~1.0 mm/h,晶体生长完成后以20～50℃/h的速率缓慢降低炉体温度。成功生长无宏观缺陷的LiCaAlF_6及Ce~(3+):LiCaAlF_6晶体样品。
(3)LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶的表征。应用XRD、紫外—可见透射光谱、红外光谱分别对生长加工后的LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶光谱性质进行表征。测试表明,LiCaAlF_6单晶吸收截止线位于深紫外区,在紫外可见光区透过率达85%以上,同时红外光谱显示,该单晶无OH-吸收带,从而证实坩埚下降法生长LiCaAlF_6单晶性能良好。Ce~(3+):LiCaAlF_6单晶表征表明266nm左右,有宽带特征吸http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php收峰Ce~(3+)宽带特征吸收峰,其红外光谱出OH-微弱吸收峰,在257,267nm波长光激发下,均可获得在290nm和310nm存在两个宽带发射峰。
(4)LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶的生长及加工工艺的改进。为降低晶体生长成品率及提高晶体生长效率,通过一炉多管或一管多坩埚进行垂直坩埚下降法生长,获得较好的晶体生长结果,为产业化批量LiCaAlF_6及Ce~(3+):LiCaAlF_6单晶生长提供实验基础。通过对晶体性能研究和晶体加工实践总结,得出适合该类单晶加工工艺。
学位年度:2010
新型金属硼酸盐的合成与性质研究
题名:新型金属硼酸盐的合成与性质研究
作者:吴淑莉
学位授予单位:宁波大学
关键词:硼酸盐;;水热合成;;无机-有机杂化;;晶体结构
摘要:
无机-有机杂化材料综合了有机物和无机物各自的优点,在力学、热学、光学、电磁学和生物学等方面具有许多优异的性能,而成为材料化学研究的热点。过去几十年以来,由于具有丰富的结构以及在二阶非线性光学材料方面的实际应用,硼酸盐材料一直是一个快速发展的领域。虽然碱金属、碱土金属、稀土和过渡金属Neodymium Magnets的硼酸盐都得到了广泛的研究和应用,但对无机-有机杂化硼酸盐的合成、结构和性质的研究却不多。因此,探索合成无机-有机杂化硼酸盐,对发现新型的功能材料具有重要的意义。
本文采用水热(溶剂热)或者溶液挥发的方法,合成出了4个无机-有机杂化的硼酸盐。在合成含锑的无机-有机杂化硼酸盐过程中意外得到了2个新的锑酸钠。使用红外光谱,X射线粉末衍射,X射线单晶衍射,热分析等手段对这些化合物进行了表征和晶体结构测定。
(1)含有机酸的无机-有机杂化硼酸盐:采用水热法/溶液挥发法合成了2种新型的无机-有机杂化硼酸盐: [Al_2(fum)(H_3BO_3)(OH)_4]_n·n(H_3BO_3)(1)和[Na_2(fum)(H_3BO_3)(H_2O)_4]_n·n(H_3BO_3)(2)。化合物(1)中,硼酸与反丁烯二酸根阴离子通过O原子与金属Al配位,形成八面体结构。扭曲的AlO6八面体以共边的形式沿a轴方向形成了[Al_2(fum)(H_3BO_3)(OH)_4]_n一维无限链。根据文献检索本文合成的[Al_2(fum)(H_3BO_3)(OH)_4]_n·n(H_3BO_3)是首例有机酸-硼酸盐基无机-有机杂化配位聚合物。化合物(2)是采用溶液法得到的,虽具有与(1)相似的结构,合成方法却不同。
(2)含有机胺的无机-有机杂化硼酸盐:采用水热法/溶液挥发法合成出2种新的无机-有机杂化硼酸盐: [Ni(C_4H_(13)N_3)_2]·[B_5O_6(OH)_4]_2(3)和[Cu(C_2H_8N_2)_2(H_3BO_3)_2]·1/2[Cu(C_2H_8N_2)_2(H_2O)_2]·1/2[Cu(C_2H_8N_2)_2]·[B_4O_5(OH)_4]_2(4)。在化合物(3)中,五硼酸根阴离子之间通过氢键形成三维超分子网格,配合物阳离子填充于网格之中。在化合物(4)中,四硼酸根阴离子与金属配合http://www.everbeenmagnet.com/物通过氢键交替相连形成一维链,进一步通过链与链之间的氢键形成三维超分子结构。
(3)锑酸盐:采用水(溶剂)热法对含铅、铋和锑的无机-有机杂化硼酸盐做了探索研究,在实验过程中,偶然得到2种新的锑酸钠:Na_4Sb_8O_(14)(5)和Na_6(OH)_3(H_2O)_(10)·Sb_6(OH)_(21)(6),它们是具有三维结构的锑酸盐,并用红外对其进行了表征。
学位年度:2010
作者:吴淑莉
学位授予单位:宁波大学
关键词:硼酸盐;;水热合成;;无机-有机杂化;;晶体结构
摘要:
无机-有机杂化材料综合了有机物和无机物各自的优点,在力学、热学、光学、电磁学和生物学等方面具有许多优异的性能,而成为材料化学研究的热点。过去几十年以来,由于具有丰富的结构以及在二阶非线性光学材料方面的实际应用,硼酸盐材料一直是一个快速发展的领域。虽然碱金属、碱土金属、稀土和过渡金属Neodymium Magnets的硼酸盐都得到了广泛的研究和应用,但对无机-有机杂化硼酸盐的合成、结构和性质的研究却不多。因此,探索合成无机-有机杂化硼酸盐,对发现新型的功能材料具有重要的意义。
本文采用水热(溶剂热)或者溶液挥发的方法,合成出了4个无机-有机杂化的硼酸盐。在合成含锑的无机-有机杂化硼酸盐过程中意外得到了2个新的锑酸钠。使用红外光谱,X射线粉末衍射,X射线单晶衍射,热分析等手段对这些化合物进行了表征和晶体结构测定。
(1)含有机酸的无机-有机杂化硼酸盐:采用水热法/溶液挥发法合成了2种新型的无机-有机杂化硼酸盐: [Al_2(fum)(H_3BO_3)(OH)_4]_n·n(H_3BO_3)(1)和[Na_2(fum)(H_3BO_3)(H_2O)_4]_n·n(H_3BO_3)(2)。化合物(1)中,硼酸与反丁烯二酸根阴离子通过O原子与金属Al配位,形成八面体结构。扭曲的AlO6八面体以共边的形式沿a轴方向形成了[Al_2(fum)(H_3BO_3)(OH)_4]_n一维无限链。根据文献检索本文合成的[Al_2(fum)(H_3BO_3)(OH)_4]_n·n(H_3BO_3)是首例有机酸-硼酸盐基无机-有机杂化配位聚合物。化合物(2)是采用溶液法得到的,虽具有与(1)相似的结构,合成方法却不同。
(2)含有机胺的无机-有机杂化硼酸盐:采用水热法/溶液挥发法合成出2种新的无机-有机杂化硼酸盐: [Ni(C_4H_(13)N_3)_2]·[B_5O_6(OH)_4]_2(3)和[Cu(C_2H_8N_2)_2(H_3BO_3)_2]·1/2[Cu(C_2H_8N_2)_2(H_2O)_2]·1/2[Cu(C_2H_8N_2)_2]·[B_4O_5(OH)_4]_2(4)。在化合物(3)中,五硼酸根阴离子之间通过氢键形成三维超分子网格,配合物阳离子填充于网格之中。在化合物(4)中,四硼酸根阴离子与金属配合http://www.everbeenmagnet.com/物通过氢键交替相连形成一维链,进一步通过链与链之间的氢键形成三维超分子结构。
(3)锑酸盐:采用水(溶剂)热法对含铅、铋和锑的无机-有机杂化硼酸盐做了探索研究,在实验过程中,偶然得到2种新的锑酸钠:Na_4Sb_8O_(14)(5)和Na_6(OH)_3(H_2O)_(10)·Sb_6(OH)_(21)(6),它们是具有三维结构的锑酸盐,并用红外对其进行了表征。
学位年度:2010
杂环类金属配合物及手性席夫碱配合物的合成、结构及表征
题名:杂环类金属配合物及手性席夫碱配合物的合成、结构及表征
作者:曹赞
学位授予单位:江西理工大学
关键词:合成;;配位;;晶体结构;;荧光
摘要:
本论文以过渡金属离子和稀土金属离子为配位离子,设计并合成了九个含联吡啶羧基配体的多核金属配合物、四唑金属配合物、手性席夫碱多核金属配合物、氰基桥联的金属配合物,解析了其单晶结构,并对部分配合物进行了光谱、热Neodymium Magnets稳定性等方面的研究。
1.利用2, 2’-联吡啶-3, 3’-二羧酸-1, 1’-二氧化物[(R, S)-H2BDCD]和CuCl_2·2H_2O (或Ba(NO_3)_2·6H_2O)进行反应,生成两个新颖的三维配位聚合物{[Cu(BDCD)_2]·H_2O}n, 1和[Ba(BDCD)_2·2H_2O]_n, 2。晶体结构测定表明化合物1中有多种纳米笼结构,化合物2是一个新颖的双核结构。
2.通过水热反应,在水和乙醇中合成杂金属聚合物{[Nd_2Cu_2(L)_2 (OXA)_4·2(2H_2O)]·2(3H_2O)}_n,3和{[EuCu(bpdc)_2·4(H_2O)I)]·2H_2O}_n, 4.晶体结构测定表明,配合物3是一个具有新颖的拓扑结构的化合物。Nd离子配位几何构型为九配位变形的三棱柱结构。Cu离子配位几何构型为五配位变形的四方锥结构。所有的2, 2’-联吡啶-3-羧酸以四配位的方式与不同的Cu原子和一个Nd原子相连接,从而在c-轴方向形成梯状结构。草酸按配位方式可分为两类,一部分以四配位的方式与不同的Cu原子和Nd原子形成两个五元环;另一部分以四配位的方式与不同的Nd原子结合形成两个五元环。配合物4通过Eu~(3+)和羧基沿a轴方向形成一维链状结构,通过Cu~(2+)和配体中的N原子沿b轴方向形成二维网状结构。
3.将氟虫腈、叠氮化钠和CuCl_2(或Cd(ClO_4)_2)溶入水和乙醇中反应,合成了化合物5,[Cu (L)_2](H_2O)_2]·2H_2O和化合物6,[Cd (L)_2](H_2O)_2]·2H_2O。晶体结构测定表明化合物5和6中的两种金属都与两个水分子、两个来自不同四唑基中的N原子和两个吡唑基中的N原子结合,构成六配位模式。Cu2+离子和Cd离子的配位几何构型为变形的八面体。在化合物5中,四唑和两个参与配位的水分子形成双重旋转轴。在这两个化合物中存在许多氢键和弱的π-π共轭作用,这有助于化合物自身的稳http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets定组装。
4.利用2,6-二甲酞基-4-甲基苯酚和(R)-2-氨基丁醇形成的schiff碱,与Cu~(2+)反应,合成了化合物7,[Cu(MBD)_2(N_3)_6]和化合物8,[Cu (MBD) Cl_4],晶体结构测定表明,化合物7是一个六核铜簇合物,而化合物8是一个双核铜。2,6-二甲酞基-4-甲基苯酚缩脂肪胺作为多齿配体通过酚羟基氧原子和醇羟基氧原子及亚胺氮原子与铜原子配位。化合物7中,Cu原子有两种配位方式:五配位和四配位。
5.将环己二胺, Cu(ClO_4)_2 ,[BuN]_3[Fe(CN)_6]进行反应,合成了化合物{2Cu (DMCL)_2·[Fe(CN)_6]}n·2H_2O, 9.晶体结构测定表明,配合物中存在μ4桥联和μ2桥联两种桥联模式。四桥联连接的四个Cu离子在同一平面内,赤道相邻氰基氮原子桥联的两个配体平面几乎是垂直的。μ~2桥联模式和μ4模式中的对位氰基氮原子桥联的两个配体平面几乎是平行的。
6.分析分子间作用力、配体构型、配位模式、辅助配体对于整个结构的影响,探索合成产物的结构特征和化学物理性能间的关系。
学位年度:2010
作者:曹赞
学位授予单位:江西理工大学
关键词:合成;;配位;;晶体结构;;荧光
摘要:
本论文以过渡金属离子和稀土金属离子为配位离子,设计并合成了九个含联吡啶羧基配体的多核金属配合物、四唑金属配合物、手性席夫碱多核金属配合物、氰基桥联的金属配合物,解析了其单晶结构,并对部分配合物进行了光谱、热Neodymium Magnets稳定性等方面的研究。
1.利用2, 2’-联吡啶-3, 3’-二羧酸-1, 1’-二氧化物[(R, S)-H2BDCD]和CuCl_2·2H_2O (或Ba(NO_3)_2·6H_2O)进行反应,生成两个新颖的三维配位聚合物{[Cu(BDCD)_2]·H_2O}n, 1和[Ba(BDCD)_2·2H_2O]_n, 2。晶体结构测定表明化合物1中有多种纳米笼结构,化合物2是一个新颖的双核结构。
2.通过水热反应,在水和乙醇中合成杂金属聚合物{[Nd_2Cu_2(L)_2 (OXA)_4·2(2H_2O)]·2(3H_2O)}_n,3和{[EuCu(bpdc)_2·4(H_2O)I)]·2H_2O}_n, 4.晶体结构测定表明,配合物3是一个具有新颖的拓扑结构的化合物。Nd离子配位几何构型为九配位变形的三棱柱结构。Cu离子配位几何构型为五配位变形的四方锥结构。所有的2, 2’-联吡啶-3-羧酸以四配位的方式与不同的Cu原子和一个Nd原子相连接,从而在c-轴方向形成梯状结构。草酸按配位方式可分为两类,一部分以四配位的方式与不同的Cu原子和Nd原子形成两个五元环;另一部分以四配位的方式与不同的Nd原子结合形成两个五元环。配合物4通过Eu~(3+)和羧基沿a轴方向形成一维链状结构,通过Cu~(2+)和配体中的N原子沿b轴方向形成二维网状结构。
3.将氟虫腈、叠氮化钠和CuCl_2(或Cd(ClO_4)_2)溶入水和乙醇中反应,合成了化合物5,[Cu (L)_2](H_2O)_2]·2H_2O和化合物6,[Cd (L)_2](H_2O)_2]·2H_2O。晶体结构测定表明化合物5和6中的两种金属都与两个水分子、两个来自不同四唑基中的N原子和两个吡唑基中的N原子结合,构成六配位模式。Cu2+离子和Cd离子的配位几何构型为变形的八面体。在化合物5中,四唑和两个参与配位的水分子形成双重旋转轴。在这两个化合物中存在许多氢键和弱的π-π共轭作用,这有助于化合物自身的稳http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets定组装。
4.利用2,6-二甲酞基-4-甲基苯酚和(R)-2-氨基丁醇形成的schiff碱,与Cu~(2+)反应,合成了化合物7,[Cu(MBD)_2(N_3)_6]和化合物8,[Cu (MBD) Cl_4],晶体结构测定表明,化合物7是一个六核铜簇合物,而化合物8是一个双核铜。2,6-二甲酞基-4-甲基苯酚缩脂肪胺作为多齿配体通过酚羟基氧原子和醇羟基氧原子及亚胺氮原子与铜原子配位。化合物7中,Cu原子有两种配位方式:五配位和四配位。
5.将环己二胺, Cu(ClO_4)_2 ,[BuN]_3[Fe(CN)_6]进行反应,合成了化合物{2Cu (DMCL)_2·[Fe(CN)_6]}n·2H_2O, 9.晶体结构测定表明,配合物中存在μ4桥联和μ2桥联两种桥联模式。四桥联连接的四个Cu离子在同一平面内,赤道相邻氰基氮原子桥联的两个配体平面几乎是垂直的。μ~2桥联模式和μ4模式中的对位氰基氮原子桥联的两个配体平面几乎是平行的。
6.分析分子间作用力、配体构型、配位模式、辅助配体对于整个结构的影响,探索合成产物的结构特征和化学物理性能间的关系。
学位年度:2010
碱土金属—含氮羧酸配合物的合成和性质研究
题名:碱土金属—含氮羧酸配合物的合成和性质研究
作者:汪快兵
学位授予单位:安庆师范学院
关键词:碱土金属配合物;;配位聚合物;;拓扑结构;;含氮羧酸
摘要:
在过去几十年间,在超分子化学和材料科学中的有机金属框架结构的合成与调查引起了人们的极大的兴趣,尤其是它们在分子识别,气体吸附,离子交换和催化等方面的潜在应用。至今为止,设计这些有机金属框架结构最基本的组装方法就是直接将金属离子与有机配体进行反应,在各种各样的有机配体当中,芳香羧酸(含氧原子)和含氮杂环由于它们的刚性结构和柔性配位模式等优点常被用作有机配体连接器来构筑超分子结构,其中含氮羧酸的优点就在于其配位点较多,可以在自组装过程中产生高维数的结构甚Neodymium Magnets至是贯穿、螺旋等特殊结构,近几年来,已经有很多文献报道了关于含氮羧酸配体的一维,二维和三维超分子结构的合成与性质,除此之外,像氢键和π···π键这类弱的非共价键在构筑分子的自组装过程中也同样起着非常重要的作用。然而,很多微妙的因素比如反应物的比例,pH值,抗衡离子和溶剂等都可能对最终结构产生影响,因此,在这个伟大的工程实现之前,想要在自组装过程中预测配合物的结构还有很漫长的路要走。
随着配位化学和主客体化学引起的广泛兴趣,文献中也出现了一定数量的IIA族金属即碱土金属配合物的结构。碱土金属的氧化态以及原子半径同二价的过渡金属和稀土金属有一定的可比性,所以原则上,碱土金属也可以与有机配体产生类似的框架结构。本论文主要内容如下:
1.以3-吡啶酸和4-吡啶酸为有机配体,碱土金属为中心离子,以反应釜煅烧为实验条件,初步探索了反应条件,反应温度等对配合物结构的影响。
2.以3-氨基-1,2,4-三氮唑-5-羧酸http://www.everbeenmagnet.com/为有机配体,碱土金属为中心离子,用分层的实验方法,探索了不同配体对结构产生的影响。
3.为了与碱土金属进行对比,采用过渡金属与有机配体进行反应,探索金属离子对结构的影响。
学位年度:2010
作者:汪快兵
学位授予单位:安庆师范学院
关键词:碱土金属配合物;;配位聚合物;;拓扑结构;;含氮羧酸
摘要:
在过去几十年间,在超分子化学和材料科学中的有机金属框架结构的合成与调查引起了人们的极大的兴趣,尤其是它们在分子识别,气体吸附,离子交换和催化等方面的潜在应用。至今为止,设计这些有机金属框架结构最基本的组装方法就是直接将金属离子与有机配体进行反应,在各种各样的有机配体当中,芳香羧酸(含氧原子)和含氮杂环由于它们的刚性结构和柔性配位模式等优点常被用作有机配体连接器来构筑超分子结构,其中含氮羧酸的优点就在于其配位点较多,可以在自组装过程中产生高维数的结构甚Neodymium Magnets至是贯穿、螺旋等特殊结构,近几年来,已经有很多文献报道了关于含氮羧酸配体的一维,二维和三维超分子结构的合成与性质,除此之外,像氢键和π···π键这类弱的非共价键在构筑分子的自组装过程中也同样起着非常重要的作用。然而,很多微妙的因素比如反应物的比例,pH值,抗衡离子和溶剂等都可能对最终结构产生影响,因此,在这个伟大的工程实现之前,想要在自组装过程中预测配合物的结构还有很漫长的路要走。
随着配位化学和主客体化学引起的广泛兴趣,文献中也出现了一定数量的IIA族金属即碱土金属配合物的结构。碱土金属的氧化态以及原子半径同二价的过渡金属和稀土金属有一定的可比性,所以原则上,碱土金属也可以与有机配体产生类似的框架结构。本论文主要内容如下:
1.以3-吡啶酸和4-吡啶酸为有机配体,碱土金属为中心离子,以反应釜煅烧为实验条件,初步探索了反应条件,反应温度等对配合物结构的影响。
2.以3-氨基-1,2,4-三氮唑-5-羧酸http://www.everbeenmagnet.com/为有机配体,碱土金属为中心离子,用分层的实验方法,探索了不同配体对结构产生的影响。
3.为了与碱土金属进行对比,采用过渡金属与有机配体进行反应,探索金属离子对结构的影响。
学位年度:2010
碱土金属—含氮羧酸配合物的合成和性质研究
题名:碱土金属—含氮羧酸配合物的合成和性质研究
作者:汪快兵
学位授予单位:安庆师范学院
关键词:碱土金属配合物;;配位聚合物;;拓扑结构;;含氮羧酸
摘要:
在过去几十年间,在超分子化学和材料科学中的有机金属框架结构的合成与调查引起了人们的极大的兴趣,尤其是它们在分子识别,气体吸附,离子交换和催化等方面的潜在应用。至今为止,设计这些有机金属框架结构最基本的组装方法就是直接将金属离子与有机配体进行反应,在各种各样的有机配体当中,芳香羧酸(含氧原子)和含氮杂环由于它们的刚性结构和柔性配位模式等优点常被用作有机配体连接器来构筑超分子结构,其中含氮羧酸的优点就在于其配位点较多,可以在自组装过程中产生高维数的结构甚至是贯穿、螺旋等特殊结构,近几年来,已经有很多文献报道了关于含氮羧酸配体的一维,二维和三维超分子结构的合成与性质,除此之外,像氢键和π···π键这类弱的非共价键在构筑分子的自组Neodymium Magnets装过程中也同样起着非常重要的作用。然而,很多微妙的因素比如反应物的比例,pH值,抗衡离子和溶剂等都可能对最终结构产生影响,因此,在这个伟大的工程实现之前,想要在自组装过程中预测配合物的结构还有很漫长的路要走。
随着配位化学和主客体化学引起的广泛兴趣,文献中也出现了一定数量的IIA族金属即碱土金属配合物的结构。碱土金属的氧化态以及原子半径同二价的过渡金属和稀土金属有一定的可比性,所以原则上,碱土金属也可以与有机配体产生类似的框架结构。本论文主要内容如下:
1.以3-吡啶酸和4-吡啶酸为有机配体,碱土金属为中心离子,以反应釜煅烧为实验条件,初步探索了反应条件,反应温度等对配合物结http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets构的影响。
2.以3-氨基-1,2,4-三氮唑-5-羧酸为有机配体,碱土金属为中心离子,用分层的实验方法,探索了不同配体对结构产生的影响。
3.为了与碱土金属进行对比,采用过渡金属与有机配体进行反应,探索金属离子对结构的影响。
学位年度:2010
作者:汪快兵
学位授予单位:安庆师范学院
关键词:碱土金属配合物;;配位聚合物;;拓扑结构;;含氮羧酸
摘要:
在过去几十年间,在超分子化学和材料科学中的有机金属框架结构的合成与调查引起了人们的极大的兴趣,尤其是它们在分子识别,气体吸附,离子交换和催化等方面的潜在应用。至今为止,设计这些有机金属框架结构最基本的组装方法就是直接将金属离子与有机配体进行反应,在各种各样的有机配体当中,芳香羧酸(含氧原子)和含氮杂环由于它们的刚性结构和柔性配位模式等优点常被用作有机配体连接器来构筑超分子结构,其中含氮羧酸的优点就在于其配位点较多,可以在自组装过程中产生高维数的结构甚至是贯穿、螺旋等特殊结构,近几年来,已经有很多文献报道了关于含氮羧酸配体的一维,二维和三维超分子结构的合成与性质,除此之外,像氢键和π···π键这类弱的非共价键在构筑分子的自组Neodymium Magnets装过程中也同样起着非常重要的作用。然而,很多微妙的因素比如反应物的比例,pH值,抗衡离子和溶剂等都可能对最终结构产生影响,因此,在这个伟大的工程实现之前,想要在自组装过程中预测配合物的结构还有很漫长的路要走。
随着配位化学和主客体化学引起的广泛兴趣,文献中也出现了一定数量的IIA族金属即碱土金属配合物的结构。碱土金属的氧化态以及原子半径同二价的过渡金属和稀土金属有一定的可比性,所以原则上,碱土金属也可以与有机配体产生类似的框架结构。本论文主要内容如下:
1.以3-吡啶酸和4-吡啶酸为有机配体,碱土金属为中心离子,以反应釜煅烧为实验条件,初步探索了反应条件,反应温度等对配合物结http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets构的影响。
2.以3-氨基-1,2,4-三氮唑-5-羧酸为有机配体,碱土金属为中心离子,用分层的实验方法,探索了不同配体对结构产生的影响。
3.为了与碱土金属进行对比,采用过渡金属与有机配体进行反应,探索金属离子对结构的影响。
学位年度:2010
固体超强酸催化废餐饮油合成生物柴油的研究
题名:固体超强酸催化废餐饮油合成生物柴油的研究
作者:孙雪
学位授予单位:大庆石油学院
关键词:生物柴油;;固体超强酸;;酯交换;;废餐饮油
摘要:
本实验采用沉淀—浸渍法在不同条件下制备了一系列固体超强酸催化剂,通过X射线衍射、红外光谱、比表面积测定表征方法考察了催化剂结构和性能的关系,并考察了反应条件对生物柴油产率的影响。通过对SO42-/MxOy型固体超强酸、稀土改性固体超强酸、SO42-/ZrO2-Al2O3和SO42-/SnO2-Al2O3的考察,筛选出活性较高Neodymium Magnets的两种固体超强酸催化剂:SO42-/ZrO2-Al2O3和SO42-/SnO2-Al2O3。研究表明:SO42-/ZrO2-Al2O3的最佳制备条件为Al2O3摩尔掺杂量5%,浸渍液浓度0.5mol/L,焙烧温度600℃,焙烧时间4h;当醇油摩尔比10:1、催化剂用量为原料油质量的4wt%、230℃反应9h,此时生物柴油的产率可达到81.42%。而SO42-/SnO2-Al2O3在Al2O3掺杂量5%,浸渍液浓度1.0mol/L,550℃焙烧4h活性达到最大。当醇油摩尔比8:1、催化剂用量为原料油质量的4wt%、250℃反应9h,此时生物柴油的产率可达到78.95%。
通过XRD和IR的表征分析表明:SO42-/ZrO2中引入Al2O3使活性四方相ZrO2更加稳定,600℃焙烧使催化剂既具有较多活性四方相ZrO2,又具有较大比表面积,从而提高了催化剂活性;而SO42-/SnO2中引入Al2O3使得活性http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets组分衍射峰增强。红外谱图显示催化剂均形成了固体超强酸结构,且改性后酸强度增大,催化剂活性中心数目增加。
学位年度:2010
作者:孙雪
学位授予单位:大庆石油学院
关键词:生物柴油;;固体超强酸;;酯交换;;废餐饮油
摘要:
本实验采用沉淀—浸渍法在不同条件下制备了一系列固体超强酸催化剂,通过X射线衍射、红外光谱、比表面积测定表征方法考察了催化剂结构和性能的关系,并考察了反应条件对生物柴油产率的影响。通过对SO42-/MxOy型固体超强酸、稀土改性固体超强酸、SO42-/ZrO2-Al2O3和SO42-/SnO2-Al2O3的考察,筛选出活性较高Neodymium Magnets的两种固体超强酸催化剂:SO42-/ZrO2-Al2O3和SO42-/SnO2-Al2O3。研究表明:SO42-/ZrO2-Al2O3的最佳制备条件为Al2O3摩尔掺杂量5%,浸渍液浓度0.5mol/L,焙烧温度600℃,焙烧时间4h;当醇油摩尔比10:1、催化剂用量为原料油质量的4wt%、230℃反应9h,此时生物柴油的产率可达到81.42%。而SO42-/SnO2-Al2O3在Al2O3掺杂量5%,浸渍液浓度1.0mol/L,550℃焙烧4h活性达到最大。当醇油摩尔比8:1、催化剂用量为原料油质量的4wt%、250℃反应9h,此时生物柴油的产率可达到78.95%。
通过XRD和IR的表征分析表明:SO42-/ZrO2中引入Al2O3使活性四方相ZrO2更加稳定,600℃焙烧使催化剂既具有较多活性四方相ZrO2,又具有较大比表面积,从而提高了催化剂活性;而SO42-/SnO2中引入Al2O3使得活性http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets组分衍射峰增强。红外谱图显示催化剂均形成了固体超强酸结构,且改性后酸强度增大,催化剂活性中心数目增加。
学位年度:2010
2012年1月29日星期日
纳米Ln-O簇构建3d-4f固体材料
题名:纳米Ln-O簇构建3d-4f固体材料
作者:韩丽洁
学位授予单位:辽宁师范大学
关键词:金属-有机配位化合物;;水热合成;;晶体结构;;性质研究
摘要:
金属-有机配位聚合物是由金属离子和桥联金属离子的有机配体共同构成的。它们是一系列固态物质,由金属为中心通过有机配体连接起来形成多维度的结构。它是一种新型材料,因其多方面的功能而备受关注。
本文以异烟酸为配体,合成了11个未见文献报道的Ln-M金属-有机配位聚合物。
1.在水热条件下,以异烟酸做配体,合成了三个同构的含Co或Ni的3d-4f配位化合物Ln_2M(IN)_8·4H_2O (Ln = Gd 1 and 3, Dy 2; M = Co 1 and 2, Ni 3)。在这组化合物中,由IN~-连接[Ln_2]单元和邻近的M中心,形成了沿bc面的一个Magnet lifter二维层状结构,在邻近层中的[Ln_2]单元和M中心被IN~-连接起来,形成了一个三维框架结构。
2.在水热条件下,以异烟酸做配体,合成了三个以纳米尺寸的CO_3@Ln_(26)球形簇为基础构建的3d-4f配位聚合物:Gd_(26)Zn_(1.5)(IN)_(26)(OAC)_7(CO_3)_(11)(OH)_(26)(H_2O)_(28) 4,Gd_(26)Mn_(0.5)(IN)_(26)(OAC)_7(CO_3)_(10)(OH)_(26)(H_2O)_(27) 5和Er_(26)Zn(IN)_(26)(OAC)_8(CO_3)_(10)(OH)_(26)(H_2O)_(23)6。其中,化合物4是由IN~-连接CO_3@Gd_(26)纳米簇和Zn(II)中心而形成的三维结构,化合物5是由IN~-连接CO_3@Gd_(26)纳米簇和Mn(II)中心形成的一维梯形链,化合物6是由CO_3@Er_(26)纳米簇和Zn(II)通过IN~-的连接而形成的一维单链结构。
3.在水热条件下,以异烟酸做配体,合成了两个同构的一维Ln-Ag配位化合物[LnAg_2(IN)_4(OAC)·5H_2O]·2H_2O (Ln = Gd 7, Eu 8; HOAC = acetic acid)。这两个化合物是由IN~-桥连Gd和Ag中心形成建筑单元,再通过Ag-Ag键形成一维链状结构。
4.在水热条件下,以异烟酸做配体,合成了两个由稀土-主族金属构建的具有新颖结构的配位化合物:Er_8[Al_2O_4(OH)_(10)](IN)_(10)(OAC)_2(H_2O)_(12.5) 9和Dy_(48)K_2(IN)_(36)(OAC)_(12)(CO_3) (O_6)(OH)_(84)(H_2O)_(50) 10。化合物9中,Er(III)与4个配位O形成立方烷状的结构,左右两侧的Er-O多面体由中http://www.999magnet.com/products/131-magnetic-lifter间的Al-O多面体连接起来形成一个封闭结构。化合物10是由配体IN~-和OAC~-以及μ_3-OH、μ_4-O和μ_5-O连接相邻的2个不对称单元形成建筑单元,再由IN~-桥连邻近的建筑单元,形成二维层状结构。
5.在水热条件下,以异烟酸做配体,合成了一个二维层状化合物Eu(IN)(CO_3)(H_2O) 11。该化合物是由CO_(32)-连接Eu-O多面体形成一个二维层,终端配体IN~-分布在层的两侧。
不仅通过单晶X-射线衍射确定了上述化合物的结构,而且对化合物的红外、热重、荧光性质进行了研究。
学位年度:2010
作者:韩丽洁
学位授予单位:辽宁师范大学
关键词:金属-有机配位化合物;;水热合成;;晶体结构;;性质研究
摘要:
金属-有机配位聚合物是由金属离子和桥联金属离子的有机配体共同构成的。它们是一系列固态物质,由金属为中心通过有机配体连接起来形成多维度的结构。它是一种新型材料,因其多方面的功能而备受关注。
本文以异烟酸为配体,合成了11个未见文献报道的Ln-M金属-有机配位聚合物。
1.在水热条件下,以异烟酸做配体,合成了三个同构的含Co或Ni的3d-4f配位化合物Ln_2M(IN)_8·4H_2O (Ln = Gd 1 and 3, Dy 2; M = Co 1 and 2, Ni 3)。在这组化合物中,由IN~-连接[Ln_2]单元和邻近的M中心,形成了沿bc面的一个Magnet lifter二维层状结构,在邻近层中的[Ln_2]单元和M中心被IN~-连接起来,形成了一个三维框架结构。
2.在水热条件下,以异烟酸做配体,合成了三个以纳米尺寸的CO_3@Ln_(26)球形簇为基础构建的3d-4f配位聚合物:Gd_(26)Zn_(1.5)(IN)_(26)(OAC)_7(CO_3)_(11)(OH)_(26)(H_2O)_(28) 4,Gd_(26)Mn_(0.5)(IN)_(26)(OAC)_7(CO_3)_(10)(OH)_(26)(H_2O)_(27) 5和Er_(26)Zn(IN)_(26)(OAC)_8(CO_3)_(10)(OH)_(26)(H_2O)_(23)6。其中,化合物4是由IN~-连接CO_3@Gd_(26)纳米簇和Zn(II)中心而形成的三维结构,化合物5是由IN~-连接CO_3@Gd_(26)纳米簇和Mn(II)中心形成的一维梯形链,化合物6是由CO_3@Er_(26)纳米簇和Zn(II)通过IN~-的连接而形成的一维单链结构。
3.在水热条件下,以异烟酸做配体,合成了两个同构的一维Ln-Ag配位化合物[LnAg_2(IN)_4(OAC)·5H_2O]·2H_2O (Ln = Gd 7, Eu 8; HOAC = acetic acid)。这两个化合物是由IN~-桥连Gd和Ag中心形成建筑单元,再通过Ag-Ag键形成一维链状结构。
4.在水热条件下,以异烟酸做配体,合成了两个由稀土-主族金属构建的具有新颖结构的配位化合物:Er_8[Al_2O_4(OH)_(10)](IN)_(10)(OAC)_2(H_2O)_(12.5) 9和Dy_(48)K_2(IN)_(36)(OAC)_(12)(CO_3) (O_6)(OH)_(84)(H_2O)_(50) 10。化合物9中,Er(III)与4个配位O形成立方烷状的结构,左右两侧的Er-O多面体由中http://www.999magnet.com/products/131-magnetic-lifter间的Al-O多面体连接起来形成一个封闭结构。化合物10是由配体IN~-和OAC~-以及μ_3-OH、μ_4-O和μ_5-O连接相邻的2个不对称单元形成建筑单元,再由IN~-桥连邻近的建筑单元,形成二维层状结构。
5.在水热条件下,以异烟酸做配体,合成了一个二维层状化合物Eu(IN)(CO_3)(H_2O) 11。该化合物是由CO_(32)-连接Eu-O多面体形成一个二维层,终端配体IN~-分布在层的两侧。
不仅通过单晶X-射线衍射确定了上述化合物的结构,而且对化合物的红外、热重、荧光性质进行了研究。
学位年度:2010
Beta分子筛择形催化合成对二异丙苯的研究
题名:Beta分子筛择形催化合成对二异丙苯的研究
作者:李世卿
学位授予单位:中国石油大学
关键词:异丙苯;;烷基化;;对二异丙苯;;Hβ分子筛;;改性;;选择性
摘要:
分子筛择形催化作为选择生成对位异构体的有效途径,一直以来都备受化工行业的重视,迄今已有很多科研人员投身这方面的研究。但作为芳烃烷基化的对位选择性催化剂,以ZSM系列、Y、MOR以及SAPO系列的研究居多,却鲜见有关β分子筛的报道。本论文主要针对β分子筛的改性和预处理方法,就异丙苯与异丙醇Magnet lifter烷基化选择生成对二异丙苯的工艺,考察了影响对位选择性的各种因素,从而采取相应的措施来达到提高选择性的目的。实验过程中采用UV、XRD、FT-IR、NH_3-TPD、BET等手段对催化剂进行表征,并将其与催化性能进行关联。具体研究结果如下:
(1)在高压釜中进行反应时,异丙苯和异丙醇烷基化的适宜反应条件是:IPA/IPB=4:1(mol),催化剂用量10w%,反应温度250℃,反应时间5h,此时异丙苯的转化率达57.2%,二异丙苯异构体中的间对位比值m/p=1.21。
(2)综合对比ZSM-5、MOR、HY以及Hβ的物化性能,发现Hβ用作异丙苯异丙基化选择生成p-DIPB的分子筛催化剂,有效酸中心多,活性高,只是选择性有待进一步提高。
(3)分别对Hβ分子筛催化剂进行覆硅改性和杂元素氧化物改性。实验发现覆硅改性后,催化剂用量10w%,反应温度为250℃时,异丙苯转化率20%,选择性提高到m/p=1.00;铜、硼、磷氧化物改性后,相同的反应条件下,异丙苯转化率为70%,选择性不变或稍有下降;稀土金属元素氧化物(Ce_2O_3及La_2O_3)改性,在异http://www.999magnet.com/products/131-magnetic-lifter丙苯转化率为30%时,产物中m/p=0.80,对位选择性大大提高。
(4)本论文在固定床微反装置上,考察扩散效应对异丙苯烷基化反应产物中异构体组成的影响。以样品4%Ceβ为前驱物,经表面覆碳预处理可获得高选择性的异丙苯烷基化催化剂,当反应条件为IPA/IPB=4:1、催化剂用量10mL、反应温度300℃、体积空速5h~(-1)、反应压力3MPa、氢气/反应原料=300(体积比)时,异丙苯转化率23%,产物组成m/p=0.66。
学位年度:2010
作者:李世卿
学位授予单位:中国石油大学
关键词:异丙苯;;烷基化;;对二异丙苯;;Hβ分子筛;;改性;;选择性
摘要:
分子筛择形催化作为选择生成对位异构体的有效途径,一直以来都备受化工行业的重视,迄今已有很多科研人员投身这方面的研究。但作为芳烃烷基化的对位选择性催化剂,以ZSM系列、Y、MOR以及SAPO系列的研究居多,却鲜见有关β分子筛的报道。本论文主要针对β分子筛的改性和预处理方法,就异丙苯与异丙醇Magnet lifter烷基化选择生成对二异丙苯的工艺,考察了影响对位选择性的各种因素,从而采取相应的措施来达到提高选择性的目的。实验过程中采用UV、XRD、FT-IR、NH_3-TPD、BET等手段对催化剂进行表征,并将其与催化性能进行关联。具体研究结果如下:
(1)在高压釜中进行反应时,异丙苯和异丙醇烷基化的适宜反应条件是:IPA/IPB=4:1(mol),催化剂用量10w%,反应温度250℃,反应时间5h,此时异丙苯的转化率达57.2%,二异丙苯异构体中的间对位比值m/p=1.21。
(2)综合对比ZSM-5、MOR、HY以及Hβ的物化性能,发现Hβ用作异丙苯异丙基化选择生成p-DIPB的分子筛催化剂,有效酸中心多,活性高,只是选择性有待进一步提高。
(3)分别对Hβ分子筛催化剂进行覆硅改性和杂元素氧化物改性。实验发现覆硅改性后,催化剂用量10w%,反应温度为250℃时,异丙苯转化率20%,选择性提高到m/p=1.00;铜、硼、磷氧化物改性后,相同的反应条件下,异丙苯转化率为70%,选择性不变或稍有下降;稀土金属元素氧化物(Ce_2O_3及La_2O_3)改性,在异http://www.999magnet.com/products/131-magnetic-lifter丙苯转化率为30%时,产物中m/p=0.80,对位选择性大大提高。
(4)本论文在固定床微反装置上,考察扩散效应对异丙苯烷基化反应产物中异构体组成的影响。以样品4%Ceβ为前驱物,经表面覆碳预处理可获得高选择性的异丙苯烷基化催化剂,当反应条件为IPA/IPB=4:1、催化剂用量10mL、反应温度300℃、体积空速5h~(-1)、反应压力3MPa、氢气/反应原料=300(体积比)时,异丙苯转化率23%,产物组成m/p=0.66。
学位年度:2010
染料木黄酮钙配合物的合成、表征、性质研究及其在异黄酮纯化中的应用
题名:染料木黄酮钙配合物的合成、表征、性质研究及其在异黄酮纯化中的应用
作者:刘潇
学位授予单位:东北农业大学
关键词:染料木黄酮;;配合物;;合成;;表征;;生物活性;;纯化
摘要:
配位作用在天然药物中普遍存在,研究发现,根据协同效应,某些天然药物中有效成分的金属配合物的生物活性明显强于单一有效成分。
染料木黄酮具有多种生物活性和生理功能。它能抗氧化、抗炎、抑菌,有弱雌激素活性,能有效地预防和抑制各种肿瘤、骨质疏松症、妇女更年期综合症及心血管疾病等多种疾病的发生。染料木黄酮的结构具有较高的超离域度,完整的大π键共轭体系,强配位氧原子和合适的空间构型,是金属离子良好的螯合配体,易与金属离Magnet lifter子进行螯合反应。因此金属离子能够促进人体的许多生理功能。根据协同效应,药物中加入金属离子不仅可以改善药物的理化性质,促进药物吸收,更重要的是还可增强药效。配合物的形成对金属元素的吸收和代谢都起重要作用。因此,研究染料木黄酮与金属形成的配合物,有助于该类化合物新型金属基药物的开发利用。
为了设计高效、低毒的抗氧化性染料木黄酮配合物,论文选用更年期女性大多缺少的钙元素为中心原子。以染料木黄酮和氢氧化钙为原料合成了染料木黄酮钙配合物。首先优选配合物形成的条件,条件实验结果显示：除了反应温度和反应时间以外,反应体系的pH是决定配合物能否形成的关键因素,合成的最优工艺条件为pH 8.5、反应温度65℃、搅拌时间8.0h,此时染料木黄酮-钙配合物的产率为77.42%。
采用红外光谱、紫外光谱、热重分析及核磁共振等手段对其结构进行了表征。结果表明：染料木黄酮以分子中的4位羰基O和5位羟基O与Ca2+配位而形成分子式为[Ca(C15H9O5)2]·2H2O的配合物。
论文通过对染料木黄酮钙配合物抗氧化活性的分析,探讨了配合物构效关系及协同作用。采用邻苯三酚自氧化法、Feton反应-邻二氮菲光度法和DPPH自由基方法分别测定了配体与配合物清除超氧自由基、羟自由基和DPPH自由基的能力。结果表明染料木黄酮及其钙配合物清除超氧自由基能力随浓度的增大逐渐增大；在相同浓度下,钙配合物的清除能力明显强于配体染料木黄酮,提高了20%。染料木黄酮具有一定的清除羟基自由基的能力,当其形成钙配合物后,其清除能力也大大增强,最高可达到65%,提高了近50%。同时配体本身及配合物抗羟自由基的活性随浓度升高有一极大值,随后则下降。染料木黄酮及其配合物均具有一定的清除DPPH自由基的能力。随着浓度的增加,二者http://www.999magnet.com/products/131-magnetic-lifter清除能力仅略有增强,在相同浓度下,配合物对DPPH自由基的清除率要高于染料木黄酮,但这种能力的提高并不明显,最高仅1%左右。
论文又考察了染料木黄酮及其配合物的抑菌性质,测定了其抑制大肠杆菌、绿脓杆菌、李斯特氏菌的能力。结果表明染料木黄酮及其配合物对大肠杆菌、李斯特氏菌、绿脓杆菌都有一定的抑菌效果。随着浓度的增大,抑菌效果明显。二者均对绿脓杆菌的抑制效果最强。相比较而言,染料木黄酮配合物的抑菌性仅略高于染料木黄酮,这可能与钙离子对细菌的生长有促进作用有关。
通过单因素及二次正交旋转设计试验,并按实际生产需要进行了修正,确立了最佳提取条件为：液固比42:1,提取时间3.7h,提取温度49℃。在此修正条件下实际测得提取率为93.12%。
应用染料木黄酮配合物合成的原理,对30%的大豆异黄酮粉进行了纯化,成功的将异黄酮粉中的主要成分染料木苷和黄豆苷进行分离,得到高纯度的染料木苷和黄豆苷。对于进一步制备活性更高的染料木黄酮和黄豆苷元具有重要意义。以期为染料木黄酮的进一步开发利用及设计低毒、高效的抗癌药物提供有价值的参考信息。
学位年度:2010
作者:刘潇
学位授予单位:东北农业大学
关键词:染料木黄酮;;配合物;;合成;;表征;;生物活性;;纯化
摘要:
配位作用在天然药物中普遍存在,研究发现,根据协同效应,某些天然药物中有效成分的金属配合物的生物活性明显强于单一有效成分。
染料木黄酮具有多种生物活性和生理功能。它能抗氧化、抗炎、抑菌,有弱雌激素活性,能有效地预防和抑制各种肿瘤、骨质疏松症、妇女更年期综合症及心血管疾病等多种疾病的发生。染料木黄酮的结构具有较高的超离域度,完整的大π键共轭体系,强配位氧原子和合适的空间构型,是金属离子良好的螯合配体,易与金属离Magnet lifter子进行螯合反应。因此金属离子能够促进人体的许多生理功能。根据协同效应,药物中加入金属离子不仅可以改善药物的理化性质,促进药物吸收,更重要的是还可增强药效。配合物的形成对金属元素的吸收和代谢都起重要作用。因此,研究染料木黄酮与金属形成的配合物,有助于该类化合物新型金属基药物的开发利用。
为了设计高效、低毒的抗氧化性染料木黄酮配合物,论文选用更年期女性大多缺少的钙元素为中心原子。以染料木黄酮和氢氧化钙为原料合成了染料木黄酮钙配合物。首先优选配合物形成的条件,条件实验结果显示：除了反应温度和反应时间以外,反应体系的pH是决定配合物能否形成的关键因素,合成的最优工艺条件为pH 8.5、反应温度65℃、搅拌时间8.0h,此时染料木黄酮-钙配合物的产率为77.42%。
采用红外光谱、紫外光谱、热重分析及核磁共振等手段对其结构进行了表征。结果表明：染料木黄酮以分子中的4位羰基O和5位羟基O与Ca2+配位而形成分子式为[Ca(C15H9O5)2]·2H2O的配合物。
论文通过对染料木黄酮钙配合物抗氧化活性的分析,探讨了配合物构效关系及协同作用。采用邻苯三酚自氧化法、Feton反应-邻二氮菲光度法和DPPH自由基方法分别测定了配体与配合物清除超氧自由基、羟自由基和DPPH自由基的能力。结果表明染料木黄酮及其钙配合物清除超氧自由基能力随浓度的增大逐渐增大；在相同浓度下,钙配合物的清除能力明显强于配体染料木黄酮,提高了20%。染料木黄酮具有一定的清除羟基自由基的能力,当其形成钙配合物后,其清除能力也大大增强,最高可达到65%,提高了近50%。同时配体本身及配合物抗羟自由基的活性随浓度升高有一极大值,随后则下降。染料木黄酮及其配合物均具有一定的清除DPPH自由基的能力。随着浓度的增加,二者http://www.999magnet.com/products/131-magnetic-lifter清除能力仅略有增强,在相同浓度下,配合物对DPPH自由基的清除率要高于染料木黄酮,但这种能力的提高并不明显,最高仅1%左右。
论文又考察了染料木黄酮及其配合物的抑菌性质,测定了其抑制大肠杆菌、绿脓杆菌、李斯特氏菌的能力。结果表明染料木黄酮及其配合物对大肠杆菌、李斯特氏菌、绿脓杆菌都有一定的抑菌效果。随着浓度的增大,抑菌效果明显。二者均对绿脓杆菌的抑制效果最强。相比较而言,染料木黄酮配合物的抑菌性仅略高于染料木黄酮,这可能与钙离子对细菌的生长有促进作用有关。
通过单因素及二次正交旋转设计试验,并按实际生产需要进行了修正,确立了最佳提取条件为：液固比42:1,提取时间3.7h,提取温度49℃。在此修正条件下实际测得提取率为93.12%。
应用染料木黄酮配合物合成的原理,对30%的大豆异黄酮粉进行了纯化,成功的将异黄酮粉中的主要成分染料木苷和黄豆苷进行分离,得到高纯度的染料木苷和黄豆苷。对于进一步制备活性更高的染料木黄酮和黄豆苷元具有重要意义。以期为染料木黄酮的进一步开发利用及设计低毒、高效的抗癌药物提供有价值的参考信息。
学位年度:2010
尼龙6/高岭土复合材料的性能研究
题名:尼龙6/高岭土复合材料的性能研究
作者:邹晓燕
学位授予单位:青岛科技大学
关键词:尼龙6高岭土;;复合材料;;结晶行为;;流变行为
摘要:
选用了三种高岭土对尼龙6进行填充改性,采用熔融共混法制备尼龙6/高岭土复合材料,对复合体系的力学性能、熔融结晶行为及流变行为进行了系统的研究。
首先通过红外光谱、X-射线衍射、扫描电Magnet lifter子显微镜和接触角测试等对三种高岭土进行了分析,结果显示,高岭土A未经过煅烧改性和偶联剂处理,而高岭土B、C则是经过煅烧和偶联剂处理的,煅烧破坏了高岭土的晶体结构而形成无定形态,活性官能团变成Si-O,Al-O四面体和Al-O八面体;高岭土A的形貌为片状、棒状,高岭土B和高岭土C的形貌呈片状,有单片也有叠片。
分别利用硅烷偶联剂、稀土偶联剂、钛酸酯偶联剂改性高岭土A,研究了改性后的高岭土填充尼龙6的力学性能变化规律,结果表明,硅烷偶联剂KH-550改性高岭土A的填充效果最好,最佳用量为1.0wt%,与未改性高岭土A的填充效果相比,其拉伸强度提高16.9%,弯曲强度提高10.4%,缺口冲击强度提高8.2%;随高岭土添加量的增多复合体系的力学性能呈现一定的变化规律,以添加量为40phr时的综合性能最佳;通过SEM观察到复合材料的冲击断面为韧性断裂。
用差示扫描量热法和X-射线衍射研究了尼龙6/高岭土复合材料的熔融结晶行为,并用三种动力学分析方法对复合材料的非等温结晶动力学进行研究。结果表明,三种高岭土的加入均使复合体系的熔融峰变窄,熔点增加;结晶峰温和结晶起始温度提高,使结晶速率增大;高岭土填料起到异相成核作用。高岭土促进了尼龙6的γ晶型的形成;非等温结晶动力学分析结果表明,Jeziorny法、Mo法均适合分析尼龙6及复合体系的非等温结晶动力学过程,而Ozawa法不适合。
用恒速型双毛细管流变仪对http://www.999magnet.com/products/131-magnetic-lifter高岭土填充尼龙6复合体系的流变行为进行分析。结果表明,在所研究的三个温度和剪切速率范围内,尼龙6及高岭土填充尼龙6复合材料的剪切粘度均随着剪切速率的增大而逐渐减小,表现为明显的假塑性流体;随着温度的升高,体系的粘度降低;随高岭土添加量的增加,复合体系的粘度增大;复合体系的非牛顿指数随温度降低、剪切速率升高、填料量增多而减小,会使材料的非线性增强;随着剪切速率的增大,三种高岭土填充尼龙6复合材料的粘流活化能逐渐减小。
学位年度:2010
作者:邹晓燕
学位授予单位:青岛科技大学
关键词:尼龙6高岭土;;复合材料;;结晶行为;;流变行为
摘要:
选用了三种高岭土对尼龙6进行填充改性,采用熔融共混法制备尼龙6/高岭土复合材料,对复合体系的力学性能、熔融结晶行为及流变行为进行了系统的研究。
首先通过红外光谱、X-射线衍射、扫描电Magnet lifter子显微镜和接触角测试等对三种高岭土进行了分析,结果显示,高岭土A未经过煅烧改性和偶联剂处理,而高岭土B、C则是经过煅烧和偶联剂处理的,煅烧破坏了高岭土的晶体结构而形成无定形态,活性官能团变成Si-O,Al-O四面体和Al-O八面体;高岭土A的形貌为片状、棒状,高岭土B和高岭土C的形貌呈片状,有单片也有叠片。
分别利用硅烷偶联剂、稀土偶联剂、钛酸酯偶联剂改性高岭土A,研究了改性后的高岭土填充尼龙6的力学性能变化规律,结果表明,硅烷偶联剂KH-550改性高岭土A的填充效果最好,最佳用量为1.0wt%,与未改性高岭土A的填充效果相比,其拉伸强度提高16.9%,弯曲强度提高10.4%,缺口冲击强度提高8.2%;随高岭土添加量的增多复合体系的力学性能呈现一定的变化规律,以添加量为40phr时的综合性能最佳;通过SEM观察到复合材料的冲击断面为韧性断裂。
用差示扫描量热法和X-射线衍射研究了尼龙6/高岭土复合材料的熔融结晶行为,并用三种动力学分析方法对复合材料的非等温结晶动力学进行研究。结果表明,三种高岭土的加入均使复合体系的熔融峰变窄,熔点增加;结晶峰温和结晶起始温度提高,使结晶速率增大;高岭土填料起到异相成核作用。高岭土促进了尼龙6的γ晶型的形成;非等温结晶动力学分析结果表明,Jeziorny法、Mo法均适合分析尼龙6及复合体系的非等温结晶动力学过程,而Ozawa法不适合。
用恒速型双毛细管流变仪对http://www.999magnet.com/products/131-magnetic-lifter高岭土填充尼龙6复合体系的流变行为进行分析。结果表明,在所研究的三个温度和剪切速率范围内,尼龙6及高岭土填充尼龙6复合材料的剪切粘度均随着剪切速率的增大而逐渐减小,表现为明显的假塑性流体;随着温度的升高,体系的粘度降低;随高岭土添加量的增加,复合体系的粘度增大;复合体系的非牛顿指数随温度降低、剪切速率升高、填料量增多而减小,会使材料的非线性增强;随着剪切速率的增大,三种高岭土填充尼龙6复合材料的粘流活化能逐渐减小。
学位年度:2010
金对纳米材料发光性能的影响
题名:金对纳米材料发光性能的影响
作者:刘红娟
学位授予单位:南昌大学
关键词:氧化锌;;氧化钇;;纳米材料;;光致发光;;等离子体;;金
摘要:
通过不同的掺杂或杂化复合来改变纳米荧光材料的发光性能,以适应不同的应用需求,这已成为当今纳米材料科学领域的前沿和热点。本论文选用传统的ZnO半导体材料和Y2O3:Eu3+稀土荧光材料作为研究对象,通过简单的共沉淀法制备出花状ZnO和一维Y2O3:Eu3+荧光纳米材料,利用贵金属Au在晶格中的引入和偏析形成杂Magnet lifter化结构来影响纳米结构的光学性能。具体内容如下：
(1)通过一个简单的共沉淀法制得Zn5(OH)6(CO3)2:Au纳米花状前驱体,并分别在260℃和800℃下退火得到ZnO/Au两个样品。在ZnO中添加Au会导致成分波动。另外,随着加热部分Au会从ZnO基体中脱溶析出附着在纳米花状结构表面,会导致界面波动和等离子体效应。因此,在低激发功率密度时,室温近带边(NBE)发射是由约束激子跃迁为主,同时由于Au等离子体共振增强使得发射强度几乎呈超线性增加。然而,在高激发强度时由于电子-空穴等离子体的产生,导致带隙重整化,带边发射红移；另一方面,由于Auger非辐射复合的形成以及这些自由的光生电子向金转移,结果造成了在更高的激发强度下近带边发射反而减弱。对绿色可见发射而言,其更可能来自导带边浅陷阱中的电子和具有双离子氧空位VO**的深陷阱空穴之间的跃迁。在这些样品中存在大量的浅陷阱中心,它们对电子的捕获比电子-空穴对的湮灭要更快,这样导带边的光生电子快速被陷阱捕获然后再与价带边的空穴复合,而不是通过禁带中的中间能级再回到价带,所以随着激发强度的增加不仅进一步使得近带边发射红移,而且近带边发射与绿色发射积分强度比增加。在260℃退火的样品中,由于Au的脱溶较少,晶格中不仅存在VO**,还存在其它类型的多种缺陷,它们能够被互相补偿。然而在800℃下退火的样品中,晶格已形成了完全平衡的状态,在晶格中形成了单一的缺陷,如VO**。因此,相对于800℃下退火的样品而言,在260℃退火的样品中缺陷发射更弱。
(2)通过使用YCl3和Y(NO3)3这两种不同的原料作为反应物,用相同的共沉淀法方法分别制备出了管状和棒状的Y2(CO3)3(H2O)2:Eu,Au前驱体,然后退火后分别得到相应的Y2O3纳米管和纳米棒。在短紫外线(251nm)激发下,。对Y2O3:0.05Eu3+在611nm处的5D0-7F2红色发射来说,纳米管的发射强度是纳米棒的67.7倍。这http://www.999magnet.com/products/131-magnetic-lifter主要是由于形状、维度和更薄的壁厚影响了Eu3+离子周围的环境。对纳米管来说,Au的添加降低了611nm处的5Do-7F2红色发射。然而对于纳米棒来说,Au的引入可以使样品的611nm处的5Do-7F2红色发射增强了46.7倍,预示着等离子体的共振增强起了作用。这说明样品的形貌和维度对光学材料的发射产生很大的影响,而且能够直接导致Au可能在样品中以不同的形式存在。相信这些Y203纳米管和纳米棒将具有广泛的应用潜力,如应用于激光材料,荧光粉,场发射器和纳米级光电设备等。
学位年度:2010
作者:刘红娟
学位授予单位:南昌大学
关键词:氧化锌;;氧化钇;;纳米材料;;光致发光;;等离子体;;金
摘要:
通过不同的掺杂或杂化复合来改变纳米荧光材料的发光性能,以适应不同的应用需求,这已成为当今纳米材料科学领域的前沿和热点。本论文选用传统的ZnO半导体材料和Y2O3:Eu3+稀土荧光材料作为研究对象,通过简单的共沉淀法制备出花状ZnO和一维Y2O3:Eu3+荧光纳米材料,利用贵金属Au在晶格中的引入和偏析形成杂Magnet lifter化结构来影响纳米结构的光学性能。具体内容如下：
(1)通过一个简单的共沉淀法制得Zn5(OH)6(CO3)2:Au纳米花状前驱体,并分别在260℃和800℃下退火得到ZnO/Au两个样品。在ZnO中添加Au会导致成分波动。另外,随着加热部分Au会从ZnO基体中脱溶析出附着在纳米花状结构表面,会导致界面波动和等离子体效应。因此,在低激发功率密度时,室温近带边(NBE)发射是由约束激子跃迁为主,同时由于Au等离子体共振增强使得发射强度几乎呈超线性增加。然而,在高激发强度时由于电子-空穴等离子体的产生,导致带隙重整化,带边发射红移；另一方面,由于Auger非辐射复合的形成以及这些自由的光生电子向金转移,结果造成了在更高的激发强度下近带边发射反而减弱。对绿色可见发射而言,其更可能来自导带边浅陷阱中的电子和具有双离子氧空位VO**的深陷阱空穴之间的跃迁。在这些样品中存在大量的浅陷阱中心,它们对电子的捕获比电子-空穴对的湮灭要更快,这样导带边的光生电子快速被陷阱捕获然后再与价带边的空穴复合,而不是通过禁带中的中间能级再回到价带,所以随着激发强度的增加不仅进一步使得近带边发射红移,而且近带边发射与绿色发射积分强度比增加。在260℃退火的样品中,由于Au的脱溶较少,晶格中不仅存在VO**,还存在其它类型的多种缺陷,它们能够被互相补偿。然而在800℃下退火的样品中,晶格已形成了完全平衡的状态,在晶格中形成了单一的缺陷,如VO**。因此,相对于800℃下退火的样品而言,在260℃退火的样品中缺陷发射更弱。
(2)通过使用YCl3和Y(NO3)3这两种不同的原料作为反应物,用相同的共沉淀法方法分别制备出了管状和棒状的Y2(CO3)3(H2O)2:Eu,Au前驱体,然后退火后分别得到相应的Y2O3纳米管和纳米棒。在短紫外线(251nm)激发下,。对Y2O3:0.05Eu3+在611nm处的5D0-7F2红色发射来说,纳米管的发射强度是纳米棒的67.7倍。这http://www.999magnet.com/products/131-magnetic-lifter主要是由于形状、维度和更薄的壁厚影响了Eu3+离子周围的环境。对纳米管来说,Au的添加降低了611nm处的5Do-7F2红色发射。然而对于纳米棒来说,Au的引入可以使样品的611nm处的5Do-7F2红色发射增强了46.7倍,预示着等离子体的共振增强起了作用。这说明样品的形貌和维度对光学材料的发射产生很大的影响,而且能够直接导致Au可能在样品中以不同的形式存在。相信这些Y203纳米管和纳米棒将具有广泛的应用潜力,如应用于激光材料,荧光粉,场发射器和纳米级光电设备等。
学位年度:2010
燃烧法制备钒酸盐发光材料及发光性研究
题名:燃烧法制备钒酸盐发光材料及发光性研究
作者:李钧甫
学位授予单位:成都理工大学
关键词:钒酸盐;;发光材料;;燃烧合成法;;柠檬酸;;发光性质
摘要:
钒酸盐类发光材料因其晶格中VO43-对稀土离子的有效敏化作用和特殊的VO43-自激活发光性质,已引起人们越来越多的关注。由于钒酸盐发光材料合成温度较低、化学稳定性和热稳定性良好,因此成为一类非常有应用前景的发光材料。目前,钒酸盐发光材料中成功商用的已有YVO4:Eu3+红粉,工业上主要采用高温固Magnet lifter相法和草酸盐沉淀法制备。高温固相法主要存在高耗能、耗时等缺点;草酸盐沉淀法则工艺过程较复杂,难于控制。而燃烧法作为一种简单、高效、节能的方法,在新材料合成与制备中有很大的应用价值。因此研究应用燃烧法制备新型钒酸盐发光材料具有重要意义。
本研究采用柠檬酸溶胶燃烧法制备了一种Eu3+离子激活的Ca3(VO4)2红色荧光粉和一种新型钒酸盐石榴石自激活荧光体Ca2KMg2V3O12。利用XRD、SEM和荧光光谱等测试技术对所制样品进行表征。详细研究了燃烧法各工艺条件对荧光粉结构、组成和发光性能的影响,并获得优化的工艺条件:Ca/V = 3:2.2、T = 900℃、n(CA):n(Ca2++V5+) = 0.8。基于此优化工艺进一步研究了Eu3+离子浓度、Na+离子或Li+离子共掺杂对Ca3(VO4)2:Eu3+红光荧光粉光谱结构的影响。研究表明Na+离子或Li+离子掺杂对提高Ca3(VO4)2:Eu3+荧光粉Eu3+离子f-f能级跃迁激发强度是有利的。
采用燃烧法工艺在600 - 900℃ http://www.999magnet.com/products/131-magnetic-lifter 间成功制备了Ca2KMg2V3O12荧光粉,其激发光谱分布于260 - 425nm之间,主峰位于320nm;发射光谱几乎覆盖整个可见光区,主峰位于520至530nm间。发光色度坐标(x, y) = (0.323 - 0.339, 0.430 - 0.447),表征该荧光粉可在紫外和近紫外光激发下发出明亮的略带黄绿色白光。Rietveld结构精修表明Ca2KMg2V3O12具石榴石型晶体结构,空间群为:Ia3d,晶胞参数:a = b = c = 12.50031±0.00041?,Z = 8。结构中[VO4]3-四面体的扭曲使其对称性偏离Td对称型,可能是Ca2KMg2V3O12具有高强度宽带发射的结构基础。
学位年度:2010
作者:李钧甫
学位授予单位:成都理工大学
关键词:钒酸盐;;发光材料;;燃烧合成法;;柠檬酸;;发光性质
摘要:
钒酸盐类发光材料因其晶格中VO43-对稀土离子的有效敏化作用和特殊的VO43-自激活发光性质,已引起人们越来越多的关注。由于钒酸盐发光材料合成温度较低、化学稳定性和热稳定性良好,因此成为一类非常有应用前景的发光材料。目前,钒酸盐发光材料中成功商用的已有YVO4:Eu3+红粉,工业上主要采用高温固Magnet lifter相法和草酸盐沉淀法制备。高温固相法主要存在高耗能、耗时等缺点;草酸盐沉淀法则工艺过程较复杂,难于控制。而燃烧法作为一种简单、高效、节能的方法,在新材料合成与制备中有很大的应用价值。因此研究应用燃烧法制备新型钒酸盐发光材料具有重要意义。
本研究采用柠檬酸溶胶燃烧法制备了一种Eu3+离子激活的Ca3(VO4)2红色荧光粉和一种新型钒酸盐石榴石自激活荧光体Ca2KMg2V3O12。利用XRD、SEM和荧光光谱等测试技术对所制样品进行表征。详细研究了燃烧法各工艺条件对荧光粉结构、组成和发光性能的影响,并获得优化的工艺条件:Ca/V = 3:2.2、T = 900℃、n(CA):n(Ca2++V5+) = 0.8。基于此优化工艺进一步研究了Eu3+离子浓度、Na+离子或Li+离子共掺杂对Ca3(VO4)2:Eu3+红光荧光粉光谱结构的影响。研究表明Na+离子或Li+离子掺杂对提高Ca3(VO4)2:Eu3+荧光粉Eu3+离子f-f能级跃迁激发强度是有利的。
采用燃烧法工艺在600 - 900℃ http://www.999magnet.com/products/131-magnetic-lifter 间成功制备了Ca2KMg2V3O12荧光粉,其激发光谱分布于260 - 425nm之间,主峰位于320nm;发射光谱几乎覆盖整个可见光区,主峰位于520至530nm间。发光色度坐标(x, y) = (0.323 - 0.339, 0.430 - 0.447),表征该荧光粉可在紫外和近紫外光激发下发出明亮的略带黄绿色白光。Rietveld结构精修表明Ca2KMg2V3O12具石榴石型晶体结构,空间群为:Ia3d,晶胞参数:a = b = c = 12.50031±0.00041?,Z = 8。结构中[VO4]3-四面体的扭曲使其对称性偏离Td对称型,可能是Ca2KMg2V3O12具有高强度宽带发射的结构基础。
学位年度:2010
北喜马拉雅扎西康铅锌锑银矿床成因研究
题名:北喜马拉雅扎西康铅锌锑银矿床成因研究
作者:张建芳
学位授予单位:中国地质大学
关键词:成因研究;;铅锌锑银;;扎西康;;北喜马拉雅
摘要:
扎西康铅锌锑银矿床位于北喜马拉雅金锑多金属成矿带的羊卓雍-拿日雍复式向斜东南端北翼。矿区目前发现矿体9条,其中Ⅵ、Ⅴ、Ⅵ号矿体是矿区的主要矿体,总资源量(332+333+3341) Pb+Zn+Sb大于100万吨,Ag大于1500吨,是北喜Magnet lifter马拉雅成矿带目前最大的、也是唯一的多金属矿床。
扎西康矿区赋矿围岩主要为下侏罗统日当组第四岩性段,岩性为灰黑色炭质板岩夹褐黄色变钙质砂岩及少量不连续分布的灰岩和辉绿岩、凝灰岩脉。矿体主要赋存于多期次活动的SN向高角度的张扭性断裂构造中,少数赋存于NNE向断裂中,严格受断裂控制,矿体上部常具有分支复合现象,下部较为连续。
矿石类型多样,矿石构造主要有块状、条带状、脉状-网脉状、角砾状、环状、晶簇状、放射状、指状构造等。矿石结构主要有自形-半自形粒状结构、它形粒状结构、骸晶结构、填隙结构、穿插结构、交代结构、包含状结构、共结边结构等。
矿石物质成分复杂,并具有一定的水平和垂直分带性,矿石矿物主要有闪锌矿、方铅矿、辉锑铅矿、硫锑铅矿、辉锑矿,少量黄铜矿、车轮矿、银黝铜矿、硫锑铅银矿、方锑矿等,偶见蓝铜矿、孔雀石；脉石矿物主要有黄铁矿、菱铁矿、石英、方解石等。氧化矿石中矿物组分以褐铁矿、菱锌矿、铅矾、锑华等为主。
根据矿体交切和矿物之间的充填交代关系,将成矿阶段划分为黄铜矿-黄铁矿-方铅矿-闪锌矿阶段、菱铁矿-微细黄铁矿方铅矿http://www.999magnet.com/products/131-magnetic-lifter闪锌矿脉阶段、石英-毒砂-黄铁矿阶段、石英-黄铁矿-车轮矿-硫锑铅矿-辉锑矿-闪锌矿-方铅矿(中细粒)阶段、方铅矿-黄铁矿(粗粒脉状)阶段以及热泉硅华(包裹矿石角砾)阶段。
包裹体测温研究表明成矿流体为中温(199～328℃)-中低盐度(0.7～12.5%)-中低密度(0.95～0.65g/cm3)范畴；流体成分变化从早阶段到晚阶段为SO42--Cl--Na+-Mg2+-K+型→SO42--Cl--Na+型→SO42--Na+型；流体包裹体的δDV-SMOW为-127‰～-135‰,δ18OH20为-13.7‰～12.4‰,偏向于西藏地热水的分布范围,晚期有大量的大气降水加入；He-Ar同位素组成表明成矿流体主要为地壳流体和饱和大气水的混合,没有明显的地幔流体成分混入。
矿石矿物黄铁矿、闪锌矿、方铅矿、硫锑铅矿、辉锑矿等硫化物的δ34S值变化为4.5‰～12.0‰,多数集中在8‰～11‰,富集重硫且变化较小,表明其硫源是一致的,主要来源于围岩中的海相地层还原硫；206Pb/204Pb、207Pb/204Pb、208Pb/204Pb比值分别在18.474～19.637,15.649～15.774和39.660～40.010范围内,并成一条直线,具有放射性异常铅的特征,投图落在上地壳铅演化线附近；区域晚三叠-早侏罗系地层中成矿元素丰度以及矿区中矿石矿物-地层-辉绿岩体的稀土微量元素特征对比表明晚三叠-早侏罗系浊流或喷流沉积的一套碳硅泥岩系地层富集成矿元素,为成矿提供了丰富的物质来源。
扎西康矿床成矿时代为18.3～23.3Ma,与北喜马拉雅地区成矿时代为13.3～24.2Ma相近,表明成矿与中新世印度与欧亚板块后碰撞挤压向伸展转换构造运动有关。北喜马拉雅地区早期阶段主要发生下地壳物质自北而南的反方向流动与上地壳缩短,形成EW向延伸的藏南拆离系(STDS),地壳部分熔融产生的岩浆沿藏南拆离系和层间破碎带侵入,在区域上构成了呈EW向分布的变质核杂岩带；而晚期阶段应力场发生重大变化,主要发生EW向伸展,形成一系列SN向正断层系统及裂谷系。与后碰撞挤压向伸展转换构造运动的同时,发生较大规模的金锑、铅锌银等成矿作用,且由于构造属性的不同导致或决定了控矿构造及成矿作用之间的差异性。如查拉普金矿、哲古金锑矿、马扎拉锑金矿、沙拉岗锑矿等主要受与藏南拆离系相关的EW向层间破碎带控制；而扎西康铅锌锑银矿、车穷卓布锑矿、壤拉锑矿等则赋存于SN向高角度张扭性断裂中。控矿构造由北往南从以EW向层间破碎带为主转变为以近SN向高角度断裂为主。此外,扎西康铅锌锑银矿床同位素组成与带内已知的金(锑)矿床有着较为明显的区别,也表明其成矿作用具有特殊性。扎西康矿床成矿流体主要为地下热水,成矿物质主要源于上地壳地层,而金(锑)矿床同位素组成更多地显示其成矿作用有岩浆流体及物质的参与。
扎西康铅锌锑银矿床成矿作用为中新世北喜马拉雅在印度板块与欧亚板块后碰撞挤压向伸展转换作用下形成一系列的伸展构造,并促使地壳部分熔融形成地壳熔融层或岩浆房,引起局部热流值剧增,地温异常梯度增大,驱动了地下热水流体的对流循环,萃取晚三叠世-早侏罗世浊流或喷流沉积的灰黑色碳硅泥岩系中的成矿物质沿着SN向高角度断裂带多阶段充填交代成矿,属于(浊流或喷流)沉积-构造-热泉水改造的多阶段充填交代热液脉状矿床。
学位年度:2010
作者:张建芳
学位授予单位:中国地质大学
关键词:成因研究;;铅锌锑银;;扎西康;;北喜马拉雅
摘要:
扎西康铅锌锑银矿床位于北喜马拉雅金锑多金属成矿带的羊卓雍-拿日雍复式向斜东南端北翼。矿区目前发现矿体9条,其中Ⅵ、Ⅴ、Ⅵ号矿体是矿区的主要矿体,总资源量(332+333+3341) Pb+Zn+Sb大于100万吨,Ag大于1500吨,是北喜Magnet lifter马拉雅成矿带目前最大的、也是唯一的多金属矿床。
扎西康矿区赋矿围岩主要为下侏罗统日当组第四岩性段,岩性为灰黑色炭质板岩夹褐黄色变钙质砂岩及少量不连续分布的灰岩和辉绿岩、凝灰岩脉。矿体主要赋存于多期次活动的SN向高角度的张扭性断裂构造中,少数赋存于NNE向断裂中,严格受断裂控制,矿体上部常具有分支复合现象,下部较为连续。
矿石类型多样,矿石构造主要有块状、条带状、脉状-网脉状、角砾状、环状、晶簇状、放射状、指状构造等。矿石结构主要有自形-半自形粒状结构、它形粒状结构、骸晶结构、填隙结构、穿插结构、交代结构、包含状结构、共结边结构等。
矿石物质成分复杂,并具有一定的水平和垂直分带性,矿石矿物主要有闪锌矿、方铅矿、辉锑铅矿、硫锑铅矿、辉锑矿,少量黄铜矿、车轮矿、银黝铜矿、硫锑铅银矿、方锑矿等,偶见蓝铜矿、孔雀石；脉石矿物主要有黄铁矿、菱铁矿、石英、方解石等。氧化矿石中矿物组分以褐铁矿、菱锌矿、铅矾、锑华等为主。
根据矿体交切和矿物之间的充填交代关系,将成矿阶段划分为黄铜矿-黄铁矿-方铅矿-闪锌矿阶段、菱铁矿-微细黄铁矿方铅矿http://www.999magnet.com/products/131-magnetic-lifter闪锌矿脉阶段、石英-毒砂-黄铁矿阶段、石英-黄铁矿-车轮矿-硫锑铅矿-辉锑矿-闪锌矿-方铅矿(中细粒)阶段、方铅矿-黄铁矿(粗粒脉状)阶段以及热泉硅华(包裹矿石角砾)阶段。
包裹体测温研究表明成矿流体为中温(199～328℃)-中低盐度(0.7～12.5%)-中低密度(0.95～0.65g/cm3)范畴；流体成分变化从早阶段到晚阶段为SO42--Cl--Na+-Mg2+-K+型→SO42--Cl--Na+型→SO42--Na+型；流体包裹体的δDV-SMOW为-127‰～-135‰,δ18OH20为-13.7‰～12.4‰,偏向于西藏地热水的分布范围,晚期有大量的大气降水加入；He-Ar同位素组成表明成矿流体主要为地壳流体和饱和大气水的混合,没有明显的地幔流体成分混入。
矿石矿物黄铁矿、闪锌矿、方铅矿、硫锑铅矿、辉锑矿等硫化物的δ34S值变化为4.5‰～12.0‰,多数集中在8‰～11‰,富集重硫且变化较小,表明其硫源是一致的,主要来源于围岩中的海相地层还原硫；206Pb/204Pb、207Pb/204Pb、208Pb/204Pb比值分别在18.474～19.637,15.649～15.774和39.660～40.010范围内,并成一条直线,具有放射性异常铅的特征,投图落在上地壳铅演化线附近；区域晚三叠-早侏罗系地层中成矿元素丰度以及矿区中矿石矿物-地层-辉绿岩体的稀土微量元素特征对比表明晚三叠-早侏罗系浊流或喷流沉积的一套碳硅泥岩系地层富集成矿元素,为成矿提供了丰富的物质来源。
扎西康矿床成矿时代为18.3～23.3Ma,与北喜马拉雅地区成矿时代为13.3～24.2Ma相近,表明成矿与中新世印度与欧亚板块后碰撞挤压向伸展转换构造运动有关。北喜马拉雅地区早期阶段主要发生下地壳物质自北而南的反方向流动与上地壳缩短,形成EW向延伸的藏南拆离系(STDS),地壳部分熔融产生的岩浆沿藏南拆离系和层间破碎带侵入,在区域上构成了呈EW向分布的变质核杂岩带；而晚期阶段应力场发生重大变化,主要发生EW向伸展,形成一系列SN向正断层系统及裂谷系。与后碰撞挤压向伸展转换构造运动的同时,发生较大规模的金锑、铅锌银等成矿作用,且由于构造属性的不同导致或决定了控矿构造及成矿作用之间的差异性。如查拉普金矿、哲古金锑矿、马扎拉锑金矿、沙拉岗锑矿等主要受与藏南拆离系相关的EW向层间破碎带控制；而扎西康铅锌锑银矿、车穷卓布锑矿、壤拉锑矿等则赋存于SN向高角度张扭性断裂中。控矿构造由北往南从以EW向层间破碎带为主转变为以近SN向高角度断裂为主。此外,扎西康铅锌锑银矿床同位素组成与带内已知的金(锑)矿床有着较为明显的区别,也表明其成矿作用具有特殊性。扎西康矿床成矿流体主要为地下热水,成矿物质主要源于上地壳地层,而金(锑)矿床同位素组成更多地显示其成矿作用有岩浆流体及物质的参与。
扎西康铅锌锑银矿床成矿作用为中新世北喜马拉雅在印度板块与欧亚板块后碰撞挤压向伸展转换作用下形成一系列的伸展构造,并促使地壳部分熔融形成地壳熔融层或岩浆房,引起局部热流值剧增,地温异常梯度增大,驱动了地下热水流体的对流循环,萃取晚三叠世-早侏罗世浊流或喷流沉积的灰黑色碳硅泥岩系中的成矿物质沿着SN向高角度断裂带多阶段充填交代成矿,属于(浊流或喷流)沉积-构造-热泉水改造的多阶段充填交代热液脉状矿床。
学位年度:2010
磁控溅射法在镁锂合金表面制备防腐涂层的研究
题名:磁控溅射法在镁锂合金表面制备防腐涂层的研究
作者:高福毅
学位授予单位:牡丹江师范学院
关键词:镁锂合金;;磁控溅射;;PVD膜层;;耐腐蚀
摘要:
镁锂合金是目前世界上最轻的金属材料,具有比强度高、抗弯强度大、极好的铸造性等优点,成为宇航、汽车、电子等领域中的首选材料。但是,镁锂合金极易被腐蚀,因此在应用方面受到了很大的限制。目前国内外对镁锂合金的研究重点以制备为主,凭借添加稀土元素来提高合金的抗腐蚀性。而采用磁控溅射技术在Magnet lifter镁锂合金表面制备防腐涂层,以提高合金抗腐蚀性的研究目前报道较少。
本文采用磁控溅射法在Mg-Li合金表面制备了多种保护涂层。利用X射线衍射仪(XRD)、S-4800冷场发射电子显微镜(SEM)、原子力显微镜(AFM)来表征薄膜的物相结构、以及表面形貌。利用电化学工作站、析氢实验以及失重实验来评价薄膜在腐蚀溶液中的抗腐蚀性能。讨论了合金以及薄膜的腐蚀机制。研究结果表明:
(1)直流磁控溅射法在镁锂合金表面沉积单层铝薄膜和钛薄膜都存在着一些缺陷,两种薄膜都存在择优取向生长,存在柱状晶体。
(2)腐蚀实验表明,单层铝薄膜的抗腐蚀性要优于单层钛薄膜;薄膜制备过程中产生的针孔及微裂纹等缺陷,构成电解质溶液到http://www.999magnet.com/products/131-magnetic-lifter达基底的通道,是导致薄膜防护作用失效的主要原因。
(3)通过反应磁控溅射法在镁锂合金表面沉积氮化铝薄膜和氮化钛薄膜。氮化钛薄膜前期防腐性能很好但是耐久性差,薄膜容易脱落;氮化铝薄膜与基体结合力较好,但是膜层不够致密。
(4)腐蚀实验表明,多层膜防护效果要优于单层膜。
学位年度:2010
作者:高福毅
学位授予单位:牡丹江师范学院
关键词:镁锂合金;;磁控溅射;;PVD膜层;;耐腐蚀
摘要:
镁锂合金是目前世界上最轻的金属材料,具有比强度高、抗弯强度大、极好的铸造性等优点,成为宇航、汽车、电子等领域中的首选材料。但是,镁锂合金极易被腐蚀,因此在应用方面受到了很大的限制。目前国内外对镁锂合金的研究重点以制备为主,凭借添加稀土元素来提高合金的抗腐蚀性。而采用磁控溅射技术在Magnet lifter镁锂合金表面制备防腐涂层,以提高合金抗腐蚀性的研究目前报道较少。
本文采用磁控溅射法在Mg-Li合金表面制备了多种保护涂层。利用X射线衍射仪(XRD)、S-4800冷场发射电子显微镜(SEM)、原子力显微镜(AFM)来表征薄膜的物相结构、以及表面形貌。利用电化学工作站、析氢实验以及失重实验来评价薄膜在腐蚀溶液中的抗腐蚀性能。讨论了合金以及薄膜的腐蚀机制。研究结果表明:
(1)直流磁控溅射法在镁锂合金表面沉积单层铝薄膜和钛薄膜都存在着一些缺陷,两种薄膜都存在择优取向生长,存在柱状晶体。
(2)腐蚀实验表明,单层铝薄膜的抗腐蚀性要优于单层钛薄膜;薄膜制备过程中产生的针孔及微裂纹等缺陷,构成电解质溶液到http://www.999magnet.com/products/131-magnetic-lifter达基底的通道,是导致薄膜防护作用失效的主要原因。
(3)通过反应磁控溅射法在镁锂合金表面沉积氮化铝薄膜和氮化钛薄膜。氮化钛薄膜前期防腐性能很好但是耐久性差,薄膜容易脱落;氮化铝薄膜与基体结合力较好,但是膜层不够致密。
(4)腐蚀实验表明,多层膜防护效果要优于单层膜。
学位年度:2010
2012年1月16日星期一
The New MFL Principle and Its Applications for Steel Pipes
The New MFL Principle and Its Applications for Steel Pipes
As a highly efficient NDT (nondestructive testing) method, MFL (Magnetic flux leakage) has been widely used for testing and evaluation of various kinds of ferromagnetic materials, especially having obvious advantages in automatic inspection of steel pipe. Up to now, the studies of MFL have a long history of nearly one hundred years. With the increasing requirements and detection index, the further research of MFL testing method and its relevant new principle is of great importance to the theory system and of benefit to find a new MFL testing method for steel pipe.Firstly, starting with the basic magnetic interaction and its relevant physical feature in electromagnetism, and combining with analysis of detection approaches and their working characteristics, the forming course of MFL of defects is described into three steps:magnetic refraction, magnetic diffusion and magnetic compression, leading to a new leaking mechanism of the MFL of defects. The proposed new theory has been confirmed and analyzed by mathematical derivation, finite element method (FEM) and experiments. It is concluded that the Magnet lifter background magnetic fields reduce the magnetic refraction but they strengthen the magnetic compression, resulting in a reduction of the MFL of defects, providing a theoretical basis for detection sensitivity of MFL.Further, a new MFL principle and its testing method based on the establishment of a near-zero background magnetic field are proposed, i.e. by reducing/or eliminating the background magnetic density and therefore the flux in the testing body leaking into the created near-zero background magnetic region with the largest refraction angle and without magnetic compression, the strongest MFL signals can be captured by magnetic sensors, reducing the signal noises caused by the background magnetic fields.
During the course of simulation and experiments, the distortions and mutations of MFL in present MFL testing method are pointed out, helping to find the root of explanation for MFL inspection signals.On the basis of the work mentioned above, taking the high-speed testing of steel pipes as an example, a new MFL technology based on orthogonal magnetization is presented, being successfully applied in the in-line inspection for coiled tubing. Additionally, a new method of MFL inspection for omni-direction defects under a unidirectional magnetization is also put forward, designing an in-line MFL testing system also successfully applied in the detection for coiled tubing and steel strip. The two inspection apparatuses have worked for over a year in the production line of coiled tubing which is the first one in China and the third one in the whole world.Meantime, a new NDT principle by using PMFP (permanent magnetic field perturbation) is proposed at the time of searching an approach of the discrimination http://www.999magnet.com/products/131-magnetic-lifter of internal and external defects, accomplishing the detection of external defects with simple structure and lowest cost. Moreover, the discrimination method of internal and external defects combining PMFP with MFL method is carried out, addressing the issue of discrimination of internal and external defects of steel pipe with a hundred percent and then accomplishing the uniform evaluation of the internal and external defects.Finally, aiming at the detailed distribution of MFL of defects, the detection signals characteristics and its formation mechanism is addressed by using finite element method of creating of multiple air region, laying a good foundation for the quantitative MFL inspection.
As a highly efficient NDT (nondestructive testing) method, MFL (Magnetic flux leakage) has been widely used for testing and evaluation of various kinds of ferromagnetic materials, especially having obvious advantages in automatic inspection of steel pipe. Up to now, the studies of MFL have a long history of nearly one hundred years. With the increasing requirements and detection index, the further research of MFL testing method and its relevant new principle is of great importance to the theory system and of benefit to find a new MFL testing method for steel pipe.Firstly, starting with the basic magnetic interaction and its relevant physical feature in electromagnetism, and combining with analysis of detection approaches and their working characteristics, the forming course of MFL of defects is described into three steps:magnetic refraction, magnetic diffusion and magnetic compression, leading to a new leaking mechanism of the MFL of defects. The proposed new theory has been confirmed and analyzed by mathematical derivation, finite element method (FEM) and experiments. It is concluded that the Magnet lifter background magnetic fields reduce the magnetic refraction but they strengthen the magnetic compression, resulting in a reduction of the MFL of defects, providing a theoretical basis for detection sensitivity of MFL.Further, a new MFL principle and its testing method based on the establishment of a near-zero background magnetic field are proposed, i.e. by reducing/or eliminating the background magnetic density and therefore the flux in the testing body leaking into the created near-zero background magnetic region with the largest refraction angle and without magnetic compression, the strongest MFL signals can be captured by magnetic sensors, reducing the signal noises caused by the background magnetic fields.
During the course of simulation and experiments, the distortions and mutations of MFL in present MFL testing method are pointed out, helping to find the root of explanation for MFL inspection signals.On the basis of the work mentioned above, taking the high-speed testing of steel pipes as an example, a new MFL technology based on orthogonal magnetization is presented, being successfully applied in the in-line inspection for coiled tubing. Additionally, a new method of MFL inspection for omni-direction defects under a unidirectional magnetization is also put forward, designing an in-line MFL testing system also successfully applied in the detection for coiled tubing and steel strip. The two inspection apparatuses have worked for over a year in the production line of coiled tubing which is the first one in China and the third one in the whole world.Meantime, a new NDT principle by using PMFP (permanent magnetic field perturbation) is proposed at the time of searching an approach of the discrimination http://www.999magnet.com/products/131-magnetic-lifter of internal and external defects, accomplishing the detection of external defects with simple structure and lowest cost. Moreover, the discrimination method of internal and external defects combining PMFP with MFL method is carried out, addressing the issue of discrimination of internal and external defects of steel pipe with a hundred percent and then accomplishing the uniform evaluation of the internal and external defects.Finally, aiming at the detailed distribution of MFL of defects, the detection signals characteristics and its formation mechanism is addressed by using finite element method of creating of multiple air region, laying a good foundation for the quantitative MFL inspection.
Research on Generator Circuit Breaker Based on Phase Controlled Switching Technology
Research on Generator Circuit Breaker Based on Phase Controlled Switching Technology
Phase-Controlled switching, also named synchronous switching or phasing controlled switch, is applied to the principle of coordinating the instant of opening or closing of a circuit with specific target point on a favorable voltage or current waveform. Controlled switching is an economical solution to reduce switching surges or to increase its breaking capacity. It is one of the advanced subjects of intelligent apparatus. To increase the breaking capability and the reliability of generator vacuum circuit breaker, the theory of generator vacuum circuit breaker has been analyzed in this paper. Based on the developed reliability model of generator circuit breaker, the synchronous control system is designed.
The obtained results in this paper supply references to the further research of the synchronous generator vacuum circuit breaker.To increase the break capability of Magnet lifter generator vacuum circuit breaker, a parallel switching method has been introduced. The related mathematic model of parallel switching is established. The transfer time of the branch current and the asynchrony are analyzed. The concrete method is presented to solve the parallel switching.The basis of Phase-controlled switching is to judge the short circuit fault exactly. Generator circuit breaker is located on the exit of the generator. The switching of the equipment and the circuit can cause the transient phenomenon. It is necessary to distinguish between the normal state and the fault state of the system. A distinguishing system applying the wavelet principle is designed in this paper. The switching strategy based on the Poltl algorithm is applied to control switching of the generator fault current.Due to the perfectly match characteristics, permanent magnetic actuator (PMA) has been widely used by vacuum circuit breaker. Based on the mathematical model of PMA, the dynamic characteristic is analyzed. The fault tree of the generator circuit breaker is constructed to increase the reliability of generator vacuum circuit breaker.The controlled switching system applied the combination of the MC68332 and FPGA. The design of software and hardware for the http://www.999magnet.com/products/131-magnetic-lifter control system is presented. In this system, MC68332 is used as the kernel. The FPGA realize the real-time sampling and the wavelet Transform. Thus the control precision and the arithmetic speed of the system are improved.Based on the above theoretical analysis, a prototype device of generator circuit breaker using PMA has been built based on controlled switching. Experiment results show that the operation of prototype device is stable and reliable. The deviations of actual switching instants are less than 1ms. The inrush current and restrike are effectively eliminated.
Phase-Controlled switching, also named synchronous switching or phasing controlled switch, is applied to the principle of coordinating the instant of opening or closing of a circuit with specific target point on a favorable voltage or current waveform. Controlled switching is an economical solution to reduce switching surges or to increase its breaking capacity. It is one of the advanced subjects of intelligent apparatus. To increase the breaking capability and the reliability of generator vacuum circuit breaker, the theory of generator vacuum circuit breaker has been analyzed in this paper. Based on the developed reliability model of generator circuit breaker, the synchronous control system is designed.
The obtained results in this paper supply references to the further research of the synchronous generator vacuum circuit breaker.To increase the break capability of Magnet lifter generator vacuum circuit breaker, a parallel switching method has been introduced. The related mathematic model of parallel switching is established. The transfer time of the branch current and the asynchrony are analyzed. The concrete method is presented to solve the parallel switching.The basis of Phase-controlled switching is to judge the short circuit fault exactly. Generator circuit breaker is located on the exit of the generator. The switching of the equipment and the circuit can cause the transient phenomenon. It is necessary to distinguish between the normal state and the fault state of the system. A distinguishing system applying the wavelet principle is designed in this paper. The switching strategy based on the Poltl algorithm is applied to control switching of the generator fault current.Due to the perfectly match characteristics, permanent magnetic actuator (PMA) has been widely used by vacuum circuit breaker. Based on the mathematical model of PMA, the dynamic characteristic is analyzed. The fault tree of the generator circuit breaker is constructed to increase the reliability of generator vacuum circuit breaker.The controlled switching system applied the combination of the MC68332 and FPGA. The design of software and hardware for the http://www.999magnet.com/products/131-magnetic-lifter control system is presented. In this system, MC68332 is used as the kernel. The FPGA realize the real-time sampling and the wavelet Transform. Thus the control precision and the arithmetic speed of the system are improved.Based on the above theoretical analysis, a prototype device of generator circuit breaker using PMA has been built based on controlled switching. Experiment results show that the operation of prototype device is stable and reliable. The deviations of actual switching instants are less than 1ms. The inrush current and restrike are effectively eliminated.
Dynamic Analysis and Control Research of the Electromechanical Integrated Toroidal Drive
Dynamic Analysis and Control Research of the Electromechanical Integrated Toroidal Drive
Electromechanical integrated toroidal drive is a kind of composite spacial drive with integration of toroidal drive and magnetic synchronous motor. In the drive, the mechanism, electricity and control are integrated, it makes the structure of the electromechanical systems simplified, it has potential application prospect at advancing edge of technical fields such as aviation and space flight. In this paper, systemic research has done at output characteristic, control theory and experiment for the drive.With the law of mechanism conversion, the relation between rotational angles of the planet and the rotor is derived, according to the magnetic teeth number of stator with different worm pole-pairs, six kinds of mounting modes are proposed. For different modes, the expression of Neodymium Magnets the mesh tooth pair number at the same time and mesh zone with worm facewidth angle is given. The output torque of electromagnetic mesh is derived, and its changes along with system parameters are discussed. The torque and speed output characteristic of six mounting modes are obtained.The electromechanical coupled dynamic model of electromechanical integrated toroidal drive is established, speed transfer function is derived, and the influence of system parameters on speed response is analyzed. Taking changes of mesh tooth pair number into account, the practical speed responses are gained.
The PI regulator is designed, the robust of control system for parameters is investigated. The response induced by disturb is solved, then, the compensating voltage and ideal output response are presented.The torque transfer function of electromechanical integrated toroidal drive is developed, and the practical torque responses with fluctuation are obtained. Using two-degree-of-freedom control method, the two-degree-of-freedom torque control system is designed for the drive, and the effects of parameters on torque response for control system are explored, then, the amendment scheme for periodic torque fluctuation is put forward. According to expected dynamic property, the independent controllers for two-degree-of-freedom speed control system are designed, compensating voltage is given, and validity of speed disturb amendment is proved.
The state-space model of electromechanical integrated toroidal drive is built. Design of optimal regulator is completed, linear feedback control law for state variables are represented, and the influence of weight coefficients selection on output performance is discussed. Considering inherent fluctuation of the drive, servo system is designed, and influence with respect to system parameter changes on servo performance is explored. Combine classic and modern control principle, the design of three-order optimal controller with regulator is achieved, smooth optimal control http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets and better tracing response are gained, so greatly improve the dynamic performance.Spiral space current of electromechanical integrated toroidal drive in worm windings is analyzed based on electromechanics, magnetomotive model of winding current and planet magnetic teeth is built, analytic expression of inductance for the drive is given, and the changes of inductance along with parameters is discussed. Flux linkage equation is constituted, the electromagnetic transient of voltage equation with constant speed is gained. Motion equations and state equation are developed combining torque equation, and the state equation of the system is solved with numeric method, the start process is simulated, following, the influence of system parameters on state variables response is presented.Employing gyroscope as sensor apparatus, the offset segment and operational amplifier are designed and fabricated, the open and closed control experiment for electromechanical integrated toroidal drive are carried out, the correctness of theoretical analyse is confirmed by comparison with theoretical results and simulink emulation, the investigation supplies foundation for further control theory research and experiment of the drive system.
Electromechanical integrated toroidal drive is a kind of composite spacial drive with integration of toroidal drive and magnetic synchronous motor. In the drive, the mechanism, electricity and control are integrated, it makes the structure of the electromechanical systems simplified, it has potential application prospect at advancing edge of technical fields such as aviation and space flight. In this paper, systemic research has done at output characteristic, control theory and experiment for the drive.With the law of mechanism conversion, the relation between rotational angles of the planet and the rotor is derived, according to the magnetic teeth number of stator with different worm pole-pairs, six kinds of mounting modes are proposed. For different modes, the expression of Neodymium Magnets the mesh tooth pair number at the same time and mesh zone with worm facewidth angle is given. The output torque of electromagnetic mesh is derived, and its changes along with system parameters are discussed. The torque and speed output characteristic of six mounting modes are obtained.The electromechanical coupled dynamic model of electromechanical integrated toroidal drive is established, speed transfer function is derived, and the influence of system parameters on speed response is analyzed. Taking changes of mesh tooth pair number into account, the practical speed responses are gained.
The PI regulator is designed, the robust of control system for parameters is investigated. The response induced by disturb is solved, then, the compensating voltage and ideal output response are presented.The torque transfer function of electromechanical integrated toroidal drive is developed, and the practical torque responses with fluctuation are obtained. Using two-degree-of-freedom control method, the two-degree-of-freedom torque control system is designed for the drive, and the effects of parameters on torque response for control system are explored, then, the amendment scheme for periodic torque fluctuation is put forward. According to expected dynamic property, the independent controllers for two-degree-of-freedom speed control system are designed, compensating voltage is given, and validity of speed disturb amendment is proved.
The state-space model of electromechanical integrated toroidal drive is built. Design of optimal regulator is completed, linear feedback control law for state variables are represented, and the influence of weight coefficients selection on output performance is discussed. Considering inherent fluctuation of the drive, servo system is designed, and influence with respect to system parameter changes on servo performance is explored. Combine classic and modern control principle, the design of three-order optimal controller with regulator is achieved, smooth optimal control http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets and better tracing response are gained, so greatly improve the dynamic performance.Spiral space current of electromechanical integrated toroidal drive in worm windings is analyzed based on electromechanics, magnetomotive model of winding current and planet magnetic teeth is built, analytic expression of inductance for the drive is given, and the changes of inductance along with parameters is discussed. Flux linkage equation is constituted, the electromagnetic transient of voltage equation with constant speed is gained. Motion equations and state equation are developed combining torque equation, and the state equation of the system is solved with numeric method, the start process is simulated, following, the influence of system parameters on state variables response is presented.Employing gyroscope as sensor apparatus, the offset segment and operational amplifier are designed and fabricated, the open and closed control experiment for electromechanical integrated toroidal drive are carried out, the correctness of theoretical analyse is confirmed by comparison with theoretical results and simulink emulation, the investigation supplies foundation for further control theory research and experiment of the drive system.
Repetitive Control Research for Low-frequency Linear Vibration Table System
Repetitive Control Research for Low-frequency Linear Vibration Table System
Low-frequency linear vibration table is an important testing device to calibrate the error model of inertial systems and instruments. In order to provide acceleration inputs within the known accuracy for inertial systems and instruments, the low- frequency vibration table should be with lower acceleration distortion. However, disturbances existing in the low-frequency linear vibration table will make its acceleration distortion worse. Therefore, how to reject or eliminate the disturbances is a serious problem to be solved. For low-frequency linear vibration table driven by permanent magnet linear synchronous motor, the disturbance forces are mainly friction force and force ripple. Considering the Neodymium Magnets operating mode of the table is reciprocating motion, thus the input signal of it is periodic, and thus the disturbance force is also periodic function. On the other hand, repetitive learning control strategy has "repeated in learning" feature, which makes it very suitable for tracking periodic signals or suppress periodic disturbances. Thus, it is of great practical and theoretical significance to the research on the low-frequency linear vibration table based on the repetitive control.As a main participant, the author took part in and has completed 985 Subject Construction Project entitled“Low-frequency Linear Vibration Table”of Harbin Institute of Technology, and based on that, several repetitive control methods are proposed in this dissertation to improve the precision of low frequency linear vibration table.
The main contents are as follows:First, we introduce the control system structure of the low-frequency linear vibration table. According to the required performance specifications, the model parameters of each module except for the controller’s are given. Based on that, the current loop controller, velocity loop controller and position loop controller are designed, respectively. A series of experiments is conducted to test each module of the realized low-frequency linear vibration table control system. Moreover, the tracking error and acceleration distortion is tested. Experimental results are given to verify the effectiveness of the system design.Considering the reference input signal and disturbances of low-frequency linear vibration table system are periodic, a discrete-time repetitive control approach is proposed to improve the tracking performance of the system. First, the stability and the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets convergence performance of the tracking error of the discrete-time repetitive control system are analyzed, and based on this condition, a criteria is given to choose the parameter of the controller.
Then, the time-delay element of the discrete-time repetitive controller is in series with lead compensation; the tracking/rejecting performance of the resulting discrete-time repetitive control system is analyzed, and a criterion is given to choose the parameter of the lead compensation element.Considering that the system model exists parametric uncertainties and the friction force exists non-parametric uncertainties, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force. According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that the system model exist parameters uncertainty and the friction force exist non-parametric uncertainty, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force.
According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that there exist model parameter and non-parameter uncertainty, and unknown disturbances in low frequency linear vibration table, an adaptive repetitive learning control law is proposed based on fuzzy basis function network (FBFN). FBFN is used to estimate the system non-parametric uncertainties and unknown disturbances, which changes the identification problem from identifying the original non-parametric uncertainties and unknown disturbances to identifying the coefficients of FBFN. The adaptive component is used to the unknown parameters of system model and fuzzy rule. The adaptive repetitive learning control law designed by Lyapunov stability theory guarantees the system stability and the tracking performance.Considering the adaptive repetitive controller mentioned above containing many control parameters, it is tedious to obtain the suitable controller parameters by try and error method. Thus, a design method of the repetitive control system based on the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets integral sliding mode is proposed to reduce the controller parameters obtained by try and error method, and compensate the uncertainty of the system. First, the linear motor driven system is extended to an uncertain system with mismatching uncertainties. The repetitive control system is obtained through introducing the repetitive controller and state feedback controller to the uncertain system. Then, the repetitive control system is converted to a time-delay system, and a sufficient condition of system stability is derived in terms of a linear matrix inequality (LMI), and based on this condition, the problem of designing the low-pass filter and the state feedback controller is converted to a nonlinear matrix inequality problem. By using generalized singular value minimization algorithm, an iterative algorithm is presented to calculate the larger cut-off angular frequency of a low-pass filter and the parameters of the state feedback controller.
Low-frequency linear vibration table is an important testing device to calibrate the error model of inertial systems and instruments. In order to provide acceleration inputs within the known accuracy for inertial systems and instruments, the low- frequency vibration table should be with lower acceleration distortion. However, disturbances existing in the low-frequency linear vibration table will make its acceleration distortion worse. Therefore, how to reject or eliminate the disturbances is a serious problem to be solved. For low-frequency linear vibration table driven by permanent magnet linear synchronous motor, the disturbance forces are mainly friction force and force ripple. Considering the Neodymium Magnets operating mode of the table is reciprocating motion, thus the input signal of it is periodic, and thus the disturbance force is also periodic function. On the other hand, repetitive learning control strategy has "repeated in learning" feature, which makes it very suitable for tracking periodic signals or suppress periodic disturbances. Thus, it is of great practical and theoretical significance to the research on the low-frequency linear vibration table based on the repetitive control.As a main participant, the author took part in and has completed 985 Subject Construction Project entitled“Low-frequency Linear Vibration Table”of Harbin Institute of Technology, and based on that, several repetitive control methods are proposed in this dissertation to improve the precision of low frequency linear vibration table.
The main contents are as follows:First, we introduce the control system structure of the low-frequency linear vibration table. According to the required performance specifications, the model parameters of each module except for the controller’s are given. Based on that, the current loop controller, velocity loop controller and position loop controller are designed, respectively. A series of experiments is conducted to test each module of the realized low-frequency linear vibration table control system. Moreover, the tracking error and acceleration distortion is tested. Experimental results are given to verify the effectiveness of the system design.Considering the reference input signal and disturbances of low-frequency linear vibration table system are periodic, a discrete-time repetitive control approach is proposed to improve the tracking performance of the system. First, the stability and the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets convergence performance of the tracking error of the discrete-time repetitive control system are analyzed, and based on this condition, a criteria is given to choose the parameter of the controller.
Then, the time-delay element of the discrete-time repetitive controller is in series with lead compensation; the tracking/rejecting performance of the resulting discrete-time repetitive control system is analyzed, and a criterion is given to choose the parameter of the lead compensation element.Considering that the system model exists parametric uncertainties and the friction force exists non-parametric uncertainties, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force. According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that the system model exist parameters uncertainty and the friction force exist non-parametric uncertainty, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force.
According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that there exist model parameter and non-parameter uncertainty, and unknown disturbances in low frequency linear vibration table, an adaptive repetitive learning control law is proposed based on fuzzy basis function network (FBFN). FBFN is used to estimate the system non-parametric uncertainties and unknown disturbances, which changes the identification problem from identifying the original non-parametric uncertainties and unknown disturbances to identifying the coefficients of FBFN. The adaptive component is used to the unknown parameters of system model and fuzzy rule. The adaptive repetitive learning control law designed by Lyapunov stability theory guarantees the system stability and the tracking performance.Considering the adaptive repetitive controller mentioned above containing many control parameters, it is tedious to obtain the suitable controller parameters by try and error method. Thus, a design method of the repetitive control system based on the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets integral sliding mode is proposed to reduce the controller parameters obtained by try and error method, and compensate the uncertainty of the system. First, the linear motor driven system is extended to an uncertain system with mismatching uncertainties. The repetitive control system is obtained through introducing the repetitive controller and state feedback controller to the uncertain system. Then, the repetitive control system is converted to a time-delay system, and a sufficient condition of system stability is derived in terms of a linear matrix inequality (LMI), and based on this condition, the problem of designing the low-pass filter and the state feedback controller is converted to a nonlinear matrix inequality problem. By using generalized singular value minimization algorithm, an iterative algorithm is presented to calculate the larger cut-off angular frequency of a low-pass filter and the parameters of the state feedback controller.
Research on Wind Power Generation Based on Multiple Armature Hybrid-excitation Generator
Research on Wind Power Generation Based on Multiple Armature Hybrid-excitation Generator
With the increasingly serious energy shortage and environmental pollution, the development and use of wind power attract people’s attention due to the wind power as a renewable green energy. Hybrid-excitation motor combines the advantages of permanent magnet motor and electric magnet motor, which main magnetic field can be adjusted and controlled with high efficiency. So the hybrid-excitation motor has broad application prospects in variable speed constant frequency wind power generation system. As wind power generation based on multiple armature hybrid-excitation generator is theme, it is carried out from theory to practice, from simulation to experiment with depth and comprehensive research. Main research contents and conclusions are as followings:(1) In order to meet the steady demand and the transient current tracking demand for three-phase grid-side converters, a Neodymium Magnets new method is proposed for the inductance design. The designed inductance will be applied in the three-phase grid-connected inverter, which will put the foundation for the subsequent simulation and experiment.(2) According to the dynamic mathematical model of three-phase grid-connected inverters, using grid voltage orientation vector control, which realizes the decoupling control for the d-axis and q-axis currents and an adjustable power factor. At the same time, it is analyzed in detail how to select the switching table according to the active power error and the reactive power error.
On this basis, a novel direct power control is proposed based on the new switching table.(3) According to the characteristics of the three-phase grid-connected inverter, the current predictive control, predictive control based on the error function and direct power predictive control are applied to three-phase grid-connected inverters. Inductance on-line identification will be applied to current predictive control and direct power prediction control as the predictive control is sensitive to filter inductance parameter. Finally, three kinds of predictive controls are done with simulation and experiment.(4) In order to improve the reliability and lower the cost for three-phase grid-connected inverters, the control strategy without grid voltage sensors based on phase-locked loop (PLL) and virtual grid flux is proposed. The control strategy without grid voltage sensors is used in vector control and current predictive control and verified by simulated and experimental results.(5) For the multiple armature hybrid-excitation generator, a new control that the DC voltage can be switched in parallel or series is proposed and is verified by experimental results. The paper analyzes the current circulation loop and constructs the average state model when the grid-connected inverters are operated in parallel. The circulation currents are inhibited by controlling the operation time for zero vectors at every PWM cycle when the space vector http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets pulse width modulation (SVPWM) algorithm is used.(6) The whole experimental platform is constructed in order to do a variety of control strategies.(7) The control strategy of maximum wind power tracking is proposed based on the hybrid-excitation generator. The speed of the hybrid-excitation generator can be controlled by controlling the excitation voltage of the hybrid-excitation generator, which makes the wind turbine run at optimum tip speed ratio. Grid voltage orientation, voltage loop and current loop are used for three-phase grid-side inverters. Finally, the mode of the whole system is established in Matlab7.4 and the simulated results verify the control strategy.
With the increasingly serious energy shortage and environmental pollution, the development and use of wind power attract people’s attention due to the wind power as a renewable green energy. Hybrid-excitation motor combines the advantages of permanent magnet motor and electric magnet motor, which main magnetic field can be adjusted and controlled with high efficiency. So the hybrid-excitation motor has broad application prospects in variable speed constant frequency wind power generation system. As wind power generation based on multiple armature hybrid-excitation generator is theme, it is carried out from theory to practice, from simulation to experiment with depth and comprehensive research. Main research contents and conclusions are as followings:(1) In order to meet the steady demand and the transient current tracking demand for three-phase grid-side converters, a Neodymium Magnets new method is proposed for the inductance design. The designed inductance will be applied in the three-phase grid-connected inverter, which will put the foundation for the subsequent simulation and experiment.(2) According to the dynamic mathematical model of three-phase grid-connected inverters, using grid voltage orientation vector control, which realizes the decoupling control for the d-axis and q-axis currents and an adjustable power factor. At the same time, it is analyzed in detail how to select the switching table according to the active power error and the reactive power error.
On this basis, a novel direct power control is proposed based on the new switching table.(3) According to the characteristics of the three-phase grid-connected inverter, the current predictive control, predictive control based on the error function and direct power predictive control are applied to three-phase grid-connected inverters. Inductance on-line identification will be applied to current predictive control and direct power prediction control as the predictive control is sensitive to filter inductance parameter. Finally, three kinds of predictive controls are done with simulation and experiment.(4) In order to improve the reliability and lower the cost for three-phase grid-connected inverters, the control strategy without grid voltage sensors based on phase-locked loop (PLL) and virtual grid flux is proposed. The control strategy without grid voltage sensors is used in vector control and current predictive control and verified by simulated and experimental results.(5) For the multiple armature hybrid-excitation generator, a new control that the DC voltage can be switched in parallel or series is proposed and is verified by experimental results. The paper analyzes the current circulation loop and constructs the average state model when the grid-connected inverters are operated in parallel. The circulation currents are inhibited by controlling the operation time for zero vectors at every PWM cycle when the space vector http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets pulse width modulation (SVPWM) algorithm is used.(6) The whole experimental platform is constructed in order to do a variety of control strategies.(7) The control strategy of maximum wind power tracking is proposed based on the hybrid-excitation generator. The speed of the hybrid-excitation generator can be controlled by controlling the excitation voltage of the hybrid-excitation generator, which makes the wind turbine run at optimum tip speed ratio. Grid voltage orientation, voltage loop and current loop are used for three-phase grid-side inverters. Finally, the mode of the whole system is established in Matlab7.4 and the simulated results verify the control strategy.
Repetitive Control Research for Low-Frequency Linear Vibration Table System
Repetitive Control Research for Low-Frequency Linear Vibration Table System
Low-frequency linear vibration table is an important testing device to calibrate the error model of inertial systems and instruments. In order to provide acceleration inputs within the known accuracy for inertial systems and instruments, the low- frequency vibration table should be with lower acceleration distortion. However, disturbances existing in the low-frequency linear vibration table will make its acceleration distortion worse. Therefore, how to reject or eliminate the disturbances is a serious problem to be solved. For low-frequency linear vibration table driven by permanent magnet linear synchronous motor, the disturbance forces are mainly friction force and force ripple. Considering the operating mode of the table is reciprocating motion, thus the input signal of it is periodic, and thus the disturbance force is also periodic function. On the other hand, repetitive learning control strategy has "repeated in Neodymium Magnets learning" feature, which makes it very suitable for tracking periodic signals or suppress periodic disturbances. Thus, it is of great practical and theoretical significance to the research on the low-frequency linear vibration table based on the repetitive control.As a main participant, the author took part in and has completed 985 Subject Construction Project entitled“Low-frequency Linear Vibration Table”of Harbin Institute of Technology, and based on that, several repetitive control methods are proposed in this dissertation to improve the precision of low frequency linear vibration table. The main contents are as follows:First, we introduce the control system structure of the low-frequency linear vibration table. According to the required performance specifications, the model parameters of each module except for the controller’s are given. Based on that, the current loop controller, velocity loop controller and position loop controller are designed, respectively. A series of experiments is conducted to test each module of the realized low-frequency linear vibration table control system.
Moreover, the tracking error and acceleration distortion is tested. Experimental results are given to verify the effectiveness of the system design.Considering the reference input signal and disturbances of low-frequency linear vibration table system are periodic, a discrete-time repetitive control approach is proposed to improve the tracking performance of the system. First, the stability and the convergence performance of the tracking error of the discrete-time repetitive control system are analyzed, and based on this condition, a criteria is given to choose the parameter of the controller. http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets Then, the time-delay element of the discrete-time repetitive controller is in series with lead compensation; the tracking/rejecting performance of the resulting discrete-time repetitive control system is analyzed, and a criterion is given to choose the parameter of the lead compensation element.Considering that the system model exists parametric uncertainties and the friction force exists non-parametric uncertainties, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force. According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that the system model exist parameters uncertainty and the friction force exist non-parametric uncertainty, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force.
According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that there exist model parameter and non-parameter uncertainty, and unknown disturbances in low frequency linear vibration table, an adaptive repetitive learning control law is proposed based on fuzzy basis function network (FBFN). FBFN is used to estimate the system non-parametric uncertainties and unknown disturbances, which changes the identification problem from identifying the original non-parametric uncertainties and unknown disturbances to identifying the coefficients of FBFN. The adaptive component is used to the unknown parameters of system model and fuzzy rule. The adaptive repetitive learning control law designed by Lyapunov stability theory guarantees the system stability and the tracking performance.Considering the adaptive repetitive controller mentioned above containing many control parameters, it is tedious to obtain the suitable controller parameters by try and error method. Thus, a design method of the repetitive control system based on the integral sliding mode is proposed to reduce the controller parameters obtained by try and error method, http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets and compensate the uncertainty of the system. First, the linear motor driven system is extended to an uncertain system with mismatching uncertainties. The repetitive control system is obtained through introducing the repetitive controller and state feedback controller to the uncertain system. Then, the repetitive control system is converted to a time-delay system, and a sufficient condition of system stability is derived in terms of a linear matrix inequality (LMI), and based on this condition, the problem of designing the low-pass filter and the state feedback controller is converted to a nonlinear matrix inequality problem. By using generalized singular value minimization algorithm, an iterative algorithm is presented to calculate the larger cut-off angular frequency of a low-pass filter and the parameters of the state feedback controller.
Low-frequency linear vibration table is an important testing device to calibrate the error model of inertial systems and instruments. In order to provide acceleration inputs within the known accuracy for inertial systems and instruments, the low- frequency vibration table should be with lower acceleration distortion. However, disturbances existing in the low-frequency linear vibration table will make its acceleration distortion worse. Therefore, how to reject or eliminate the disturbances is a serious problem to be solved. For low-frequency linear vibration table driven by permanent magnet linear synchronous motor, the disturbance forces are mainly friction force and force ripple. Considering the operating mode of the table is reciprocating motion, thus the input signal of it is periodic, and thus the disturbance force is also periodic function. On the other hand, repetitive learning control strategy has "repeated in Neodymium Magnets learning" feature, which makes it very suitable for tracking periodic signals or suppress periodic disturbances. Thus, it is of great practical and theoretical significance to the research on the low-frequency linear vibration table based on the repetitive control.As a main participant, the author took part in and has completed 985 Subject Construction Project entitled“Low-frequency Linear Vibration Table”of Harbin Institute of Technology, and based on that, several repetitive control methods are proposed in this dissertation to improve the precision of low frequency linear vibration table. The main contents are as follows:First, we introduce the control system structure of the low-frequency linear vibration table. According to the required performance specifications, the model parameters of each module except for the controller’s are given. Based on that, the current loop controller, velocity loop controller and position loop controller are designed, respectively. A series of experiments is conducted to test each module of the realized low-frequency linear vibration table control system.
Moreover, the tracking error and acceleration distortion is tested. Experimental results are given to verify the effectiveness of the system design.Considering the reference input signal and disturbances of low-frequency linear vibration table system are periodic, a discrete-time repetitive control approach is proposed to improve the tracking performance of the system. First, the stability and the convergence performance of the tracking error of the discrete-time repetitive control system are analyzed, and based on this condition, a criteria is given to choose the parameter of the controller. http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets Then, the time-delay element of the discrete-time repetitive controller is in series with lead compensation; the tracking/rejecting performance of the resulting discrete-time repetitive control system is analyzed, and a criterion is given to choose the parameter of the lead compensation element.Considering that the system model exists parametric uncertainties and the friction force exists non-parametric uncertainties, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force. According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that the system model exist parameters uncertainty and the friction force exist non-parametric uncertainty, an adaptive repetitive learning control law is proposed based on function approximation technique. First, by using the function approximation technique, the non-parameter uncertainties of the friction force is transformed into the linear combination of orthogonal function. Then, the unknown parameters of system model and the linear combination are estimated based on the adaptive mechanism; the repetitive learning component is used to improve the tracking/rejection performance of the periodic input signal/disturbance force.
According to the Lyapunov stability theory, an adaptive repetitive learning control scheme that guarantees the stability and the convergence of position tracking error of the system is designed.Considering that there exist model parameter and non-parameter uncertainty, and unknown disturbances in low frequency linear vibration table, an adaptive repetitive learning control law is proposed based on fuzzy basis function network (FBFN). FBFN is used to estimate the system non-parametric uncertainties and unknown disturbances, which changes the identification problem from identifying the original non-parametric uncertainties and unknown disturbances to identifying the coefficients of FBFN. The adaptive component is used to the unknown parameters of system model and fuzzy rule. The adaptive repetitive learning control law designed by Lyapunov stability theory guarantees the system stability and the tracking performance.Considering the adaptive repetitive controller mentioned above containing many control parameters, it is tedious to obtain the suitable controller parameters by try and error method. Thus, a design method of the repetitive control system based on the integral sliding mode is proposed to reduce the controller parameters obtained by try and error method, http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets and compensate the uncertainty of the system. First, the linear motor driven system is extended to an uncertain system with mismatching uncertainties. The repetitive control system is obtained through introducing the repetitive controller and state feedback controller to the uncertain system. Then, the repetitive control system is converted to a time-delay system, and a sufficient condition of system stability is derived in terms of a linear matrix inequality (LMI), and based on this condition, the problem of designing the low-pass filter and the state feedback controller is converted to a nonlinear matrix inequality problem. By using generalized singular value minimization algorithm, an iterative algorithm is presented to calculate the larger cut-off angular frequency of a low-pass filter and the parameters of the state feedback controller.
Study on the Micro Electromagnetic Vibration Energy Harvester Based on MEMS Technology
Study on the Micro Electromagnetic Vibration Energy Harvester Based on MEMS Technology
The recent advances in microelectronics technology and the design of ultra low power VLSI systems have been making various electronic devices smaller, wireless, portable and low power consumption. Such advance has led to many new applications such as medical implants, embedded sensors and microsystems, wearable devices and wireless sensor networks. However, how to power these micro devices effectively is becoming a key question which limits their practical application. The power consumption of these devices is very low and even in the level ofμW. Meanwhile, they are often used in very bad environment inaccessible to mankind or completely embedded in the structures without any physical connection to the outside world. So they have very high requirements for the volume, Neodymium Magnets cost, lifetime and performance of power supply. The conventional power supplies of these devices are battery and electrical cable.
Battery has a short lifetime, contains a finite amount of chemical energy and is bulky compared to micro devices. And it is hardly possible to periodically replace the batteries for lots of wireless sensor nods. On the other hand, electrical cable limits the application of various embedded wireless sensors and microsystems. As a result, the conventional power supply can not satisfy their power requirements. Energy harvesting technology can convert light, heat and kinetic energy available in the sensor’s environment into electrical energy and substitute the conventional power supply for powering various micro devices. So they are attracting more and more attention from academic and industrial field.This dissertation mainly focuses on electromagnetic vibration energy harvester based on MEMS technology. A novel sandwiched electromagnetic vibration energy harvester with air channel is presented in this work; the energy harvester prototype is fabricated by silicon bulk micromachining and microelectroplating technique, and the performance of the prototype is measured and analyzed totally.
The main work and the conclusion of this dissertation are in the following:1. The physical model of the electromagnetic vibration energy harvester was build including the physical model of vibration harvesting system and that of energy conversion system. The dynamic response of vibration harvesting system under different vibration excitation was solved and used to analyze the influence of damping ratio and vibration frequency on the amplitude-frequency and phase-frequency characteristics. In the physical model of energy conversion system, the average power dissipated within the damper and the power delivered to the electrical domain was calculated and then used to analyze the relationship between output power and input vibration amplitude, resonant frequency, damping ratio and http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets so on. Some conclusions were drawn from the analysis of physical models, which can be used to resonantly design the electromagnetic vibration energy harvester.2. A micro electromagnetic vibration energy harvester based on MEMS technology was presented which includes an NdFeB permanent magnet, a planar spiral nickel spring on silicon and a double-layer copper coil. The nickel spring on silicon was fabricated by silicon bulk micromachining and microelectroplating technique. This fabrication method not only can overcome the disadvantage of low precision brought by conventional mechanical process technology, but also can overcome the disadvantage of high cost brought by silicon deep etching technology. Meanwhile, the gap between magnet and coil can be controlled precisely by using silicon wafer with different thickness.
The method of using microelectroplated nickel to fabricate planar spring and the design of spiral shape of spring’s beam are very helpful to decrease the natural frequency of vibration harvesting system. Structure static analysis, modal analysis and harmonic analysis of the magnet-spring system were carried out using finite element analysis software--ANSYS. The influence of structure parameters of the planar spring and the magnet on the vibration characteristics of the magnet-spring system was analyzed. Ansoft Maxwell software was used to simulate the electromagnetic characteristics of the energy conversion system and to analyze the relationship between output performance and the structure parameters of coil and the magnet. The optimized structure of the vibration energy harvester was obtained from the optimization results.3. A novel sandwiched electromagnetic vibration energy harvester with air channel was presented, which includes an up coil, a magnet-spring system and a bottom coil. Its sandwiched structure is clearly different with other published prototypes. The symmetrical arrangement of two coils can make the magnetic field be utilized sufficiently and the air channel in silicon frame can decrease the air damping efficiently, both of which can increase the energy conversion efficiency. Meanwhile, the up coil can protect the magnet-spring system from being harmed. The electromagnetic simulation results show that the output voltage of the sandwiched energy harvester is increased 61% comparing with that generated by the energy harvester with single coil.
The influence of the phase difference of induced voltage from up and bottom coil on the voltage generated in series coil was also analyzed.4. The electromagnetic vibration energy harvester prototypes were fabricated using MEMS micromachining technique. Microelectroplating technique and polishing technique of polyimide were used to fabricate double-layer copper coil. The planar nickel spring on silicon frame was fabricated using double-side photolithography, bulk silicon micromachining technique and microelectroplating technique. At last, the NdFeB permanent magnet, planar nickel spring and micro coil were assembled into different energy harvester prototypes.5. The output performance of the energy harvester prototype was measured completely. The testing results of the magnet-spring system show that the spring constant of the planar nickel spring is 145.6N/m and the natural frequency of the vibration system is 228.2Hz. The reason about the difference between the simulation results http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets and the tested results was given. The tested results also show that the input vibration acceleration has great influence on the resonant amplitude and resonant frequency. The electrical output performances of three different prototypes were tested. The maximal output voltage and output power of the prototype with single coil are 101mV and 19.5μW respectively, under the vibration excitation of 0.8g acceleration and 280.9Hz. The output voltage of the sealed sandwiched energy harvester prototype is 125mV which is increased 23.8% comparing with that of the prototype with single coil. The induced voltage of the sandwiched energy harvester prototype with air channel is 162.5mV which is increased 60.8% comparing with that of the prototype with single coil. The tested results show that the maximal output power of the sandwiched energy harvester prototype with air channel is 21.2μW. Meanwhile, the tested results also show that the nonlinear vibration behavior of the spring can increase the bandwidth of the amplitude-frequency curve of the output voltage of the prototype. So the nonlinear vibration of spring can be used to realize the wideband operation of energy harvester.
The recent advances in microelectronics technology and the design of ultra low power VLSI systems have been making various electronic devices smaller, wireless, portable and low power consumption. Such advance has led to many new applications such as medical implants, embedded sensors and microsystems, wearable devices and wireless sensor networks. However, how to power these micro devices effectively is becoming a key question which limits their practical application. The power consumption of these devices is very low and even in the level ofμW. Meanwhile, they are often used in very bad environment inaccessible to mankind or completely embedded in the structures without any physical connection to the outside world. So they have very high requirements for the volume, Neodymium Magnets cost, lifetime and performance of power supply. The conventional power supplies of these devices are battery and electrical cable.
Battery has a short lifetime, contains a finite amount of chemical energy and is bulky compared to micro devices. And it is hardly possible to periodically replace the batteries for lots of wireless sensor nods. On the other hand, electrical cable limits the application of various embedded wireless sensors and microsystems. As a result, the conventional power supply can not satisfy their power requirements. Energy harvesting technology can convert light, heat and kinetic energy available in the sensor’s environment into electrical energy and substitute the conventional power supply for powering various micro devices. So they are attracting more and more attention from academic and industrial field.This dissertation mainly focuses on electromagnetic vibration energy harvester based on MEMS technology. A novel sandwiched electromagnetic vibration energy harvester with air channel is presented in this work; the energy harvester prototype is fabricated by silicon bulk micromachining and microelectroplating technique, and the performance of the prototype is measured and analyzed totally.
The main work and the conclusion of this dissertation are in the following:1. The physical model of the electromagnetic vibration energy harvester was build including the physical model of vibration harvesting system and that of energy conversion system. The dynamic response of vibration harvesting system under different vibration excitation was solved and used to analyze the influence of damping ratio and vibration frequency on the amplitude-frequency and phase-frequency characteristics. In the physical model of energy conversion system, the average power dissipated within the damper and the power delivered to the electrical domain was calculated and then used to analyze the relationship between output power and input vibration amplitude, resonant frequency, damping ratio and http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets so on. Some conclusions were drawn from the analysis of physical models, which can be used to resonantly design the electromagnetic vibration energy harvester.2. A micro electromagnetic vibration energy harvester based on MEMS technology was presented which includes an NdFeB permanent magnet, a planar spiral nickel spring on silicon and a double-layer copper coil. The nickel spring on silicon was fabricated by silicon bulk micromachining and microelectroplating technique. This fabrication method not only can overcome the disadvantage of low precision brought by conventional mechanical process technology, but also can overcome the disadvantage of high cost brought by silicon deep etching technology. Meanwhile, the gap between magnet and coil can be controlled precisely by using silicon wafer with different thickness.
The method of using microelectroplated nickel to fabricate planar spring and the design of spiral shape of spring’s beam are very helpful to decrease the natural frequency of vibration harvesting system. Structure static analysis, modal analysis and harmonic analysis of the magnet-spring system were carried out using finite element analysis software--ANSYS. The influence of structure parameters of the planar spring and the magnet on the vibration characteristics of the magnet-spring system was analyzed. Ansoft Maxwell software was used to simulate the electromagnetic characteristics of the energy conversion system and to analyze the relationship between output performance and the structure parameters of coil and the magnet. The optimized structure of the vibration energy harvester was obtained from the optimization results.3. A novel sandwiched electromagnetic vibration energy harvester with air channel was presented, which includes an up coil, a magnet-spring system and a bottom coil. Its sandwiched structure is clearly different with other published prototypes. The symmetrical arrangement of two coils can make the magnetic field be utilized sufficiently and the air channel in silicon frame can decrease the air damping efficiently, both of which can increase the energy conversion efficiency. Meanwhile, the up coil can protect the magnet-spring system from being harmed. The electromagnetic simulation results show that the output voltage of the sandwiched energy harvester is increased 61% comparing with that generated by the energy harvester with single coil.
The influence of the phase difference of induced voltage from up and bottom coil on the voltage generated in series coil was also analyzed.4. The electromagnetic vibration energy harvester prototypes were fabricated using MEMS micromachining technique. Microelectroplating technique and polishing technique of polyimide were used to fabricate double-layer copper coil. The planar nickel spring on silicon frame was fabricated using double-side photolithography, bulk silicon micromachining technique and microelectroplating technique. At last, the NdFeB permanent magnet, planar nickel spring and micro coil were assembled into different energy harvester prototypes.5. The output performance of the energy harvester prototype was measured completely. The testing results of the magnet-spring system show that the spring constant of the planar nickel spring is 145.6N/m and the natural frequency of the vibration system is 228.2Hz. The reason about the difference between the simulation results http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets and the tested results was given. The tested results also show that the input vibration acceleration has great influence on the resonant amplitude and resonant frequency. The electrical output performances of three different prototypes were tested. The maximal output voltage and output power of the prototype with single coil are 101mV and 19.5μW respectively, under the vibration excitation of 0.8g acceleration and 280.9Hz. The output voltage of the sealed sandwiched energy harvester prototype is 125mV which is increased 23.8% comparing with that of the prototype with single coil. The induced voltage of the sandwiched energy harvester prototype with air channel is 162.5mV which is increased 60.8% comparing with that of the prototype with single coil. The tested results show that the maximal output power of the sandwiched energy harvester prototype with air channel is 21.2μW. Meanwhile, the tested results also show that the nonlinear vibration behavior of the spring can increase the bandwidth of the amplitude-frequency curve of the output voltage of the prototype. So the nonlinear vibration of spring can be used to realize the wideband operation of energy harvester.
Dynamic Modeling and Control of a 2-DOF Redundantly Actuated Parallel Robot
Dynamic Modeling and Control of a 2-DOF Redundantly Actuated Parallel Robot
In comparison with serial robots, parallel robots have very good performances in terms of rigidity, accuracy and ability to manipulate large loads. In order to avoid or reduce singularity, and optimize motor torques, actuation redundancy is introduced into parallel robots. However, due to the closed-loop existing in parallel robots, the motions of these mechanisms are rather complex. Meanwhile, it is hard to control parallel robots, because of the MIMO system with time-varying, strong coupling and nonlinear dynamic properties. In this paper, a 2-DOF redundantly actuated parallel robot was taken as the object of study. The study contents mostly included kinematic analysis, electromechanical coupling dynamic modeling, control system design, and experimental test.The effects of assembly Neodymium Magnets configuration on the velocity and acceleration performance were studied. All types of assembly configuration were found by the forward position analysis and the inverse position analysis. Then the velocity performance index and acceleration performance index were introduced into the performance analysis of the configuration. The Jacobian matrix and the Hessian matrix were established by adopting the influence coefficient matrix. According to the given velocity and acceleration performance index, the corresponding performance atlas was plotted. Considering the workspace analysis, the singular configuration, the velocity performance and the acceleration performance, the optimal type of assembly configuration was pointed out. So the blindness of mechanism design can be reduced and the efficiency of optimization can be raised.
And it is beneficial to realize high precision trajectory tracking control of parallel robots.Dynamic deals with the relationship between the input torque of motors and the displacements, velocities, and accelerations of the parts of the system. In order to develop an effective controller for optimal trajectory tracking performance, the dynamics of a mechanism must be thoroughly analyzed. The steps of establishing the electromechanical coupling dynamic model were as follows:Firstly, by using the Lagrange method we got three open-loop two-bar mechanisms, by loading constraints we got the dynamic model of the parallel mechanism. The modeling process was simplified and the practical performance of the models was enhanced by using the mature dynamic model of the open-loop two-bar mechanism. Secondly, the dynamic model of the permanent-magnet AC servomotor was formulated using the field orient control principle. Thirdly, two dynamic models were integrated via torque pass, so we got the electromechanical coupling dynamic model. Lastly, through dynamic analysis, we got the trajectory http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets tracking results of the end-effector, the angular displacement of the three active joints, and the motors’current.The nonlinear proportional integral differential (PID) is insensitive to the change of system parameters, and the diagonal recurrent neural network (DRNN) control has the nonlinear approach ability. So considering both of the advantages of the nonlinear PID and DRNN, we designed a new compound intelligent controller. Comparing the new compound intelligent controller with the traditional PID controller and the diagonal recurrent neural network self-tunning PID controller, we found that the new compound intelligent controller had the best performance not only for the circular trajectory with initial errors, but also for the symmetric trapezoidal trajectory.
The new compound intelligent controller overcomes deficiency of the traditional single controller, and has a good robustness, so it is helpful to improve the tracking performance.In order to deal with external disturbance, sliding mode control schemes were introduced into trajectory tracking control of the parallel robot. The terminal sliding mode control not only guarantees the existence of the sliding phase of the closed-loop system, but also guarantees that the tracking error converges to zero under limit time. In order to deal with modeling error and external disturbance, the neuro-sliding mode control was derived. The RBF neural networks were used to approximate the discontinuous part of control gain in a classical sliding mode controller. Through the numerical simulation, the effectiveness of the sliding mode control methods was verified.The experiments on the dynamic properties and trajectory tracking control of the 2-DOF redundantly actuated parallel robots were carried out. Tests of vibration and frequency characteristic were finished. The electromechanical coupling dynamic model was verified by the symmetric trapezoidal trajectory tracking control experiment. On the basis of traditional PID http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets controller, velocity and acceleration feed-forward control was introduced to improve the trajectory tracking performance.The work of this dissertation will lay a solid foundation for further application study of redundantly actuated parallel robots, and will give reference to theory and application study of other types of parallel robots. This will help parallel robots operate with high quality.
In comparison with serial robots, parallel robots have very good performances in terms of rigidity, accuracy and ability to manipulate large loads. In order to avoid or reduce singularity, and optimize motor torques, actuation redundancy is introduced into parallel robots. However, due to the closed-loop existing in parallel robots, the motions of these mechanisms are rather complex. Meanwhile, it is hard to control parallel robots, because of the MIMO system with time-varying, strong coupling and nonlinear dynamic properties. In this paper, a 2-DOF redundantly actuated parallel robot was taken as the object of study. The study contents mostly included kinematic analysis, electromechanical coupling dynamic modeling, control system design, and experimental test.The effects of assembly Neodymium Magnets configuration on the velocity and acceleration performance were studied. All types of assembly configuration were found by the forward position analysis and the inverse position analysis. Then the velocity performance index and acceleration performance index were introduced into the performance analysis of the configuration. The Jacobian matrix and the Hessian matrix were established by adopting the influence coefficient matrix. According to the given velocity and acceleration performance index, the corresponding performance atlas was plotted. Considering the workspace analysis, the singular configuration, the velocity performance and the acceleration performance, the optimal type of assembly configuration was pointed out. So the blindness of mechanism design can be reduced and the efficiency of optimization can be raised.
And it is beneficial to realize high precision trajectory tracking control of parallel robots.Dynamic deals with the relationship between the input torque of motors and the displacements, velocities, and accelerations of the parts of the system. In order to develop an effective controller for optimal trajectory tracking performance, the dynamics of a mechanism must be thoroughly analyzed. The steps of establishing the electromechanical coupling dynamic model were as follows:Firstly, by using the Lagrange method we got three open-loop two-bar mechanisms, by loading constraints we got the dynamic model of the parallel mechanism. The modeling process was simplified and the practical performance of the models was enhanced by using the mature dynamic model of the open-loop two-bar mechanism. Secondly, the dynamic model of the permanent-magnet AC servomotor was formulated using the field orient control principle. Thirdly, two dynamic models were integrated via torque pass, so we got the electromechanical coupling dynamic model. Lastly, through dynamic analysis, we got the trajectory http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets tracking results of the end-effector, the angular displacement of the three active joints, and the motors’current.The nonlinear proportional integral differential (PID) is insensitive to the change of system parameters, and the diagonal recurrent neural network (DRNN) control has the nonlinear approach ability. So considering both of the advantages of the nonlinear PID and DRNN, we designed a new compound intelligent controller. Comparing the new compound intelligent controller with the traditional PID controller and the diagonal recurrent neural network self-tunning PID controller, we found that the new compound intelligent controller had the best performance not only for the circular trajectory with initial errors, but also for the symmetric trapezoidal trajectory.
The new compound intelligent controller overcomes deficiency of the traditional single controller, and has a good robustness, so it is helpful to improve the tracking performance.In order to deal with external disturbance, sliding mode control schemes were introduced into trajectory tracking control of the parallel robot. The terminal sliding mode control not only guarantees the existence of the sliding phase of the closed-loop system, but also guarantees that the tracking error converges to zero under limit time. In order to deal with modeling error and external disturbance, the neuro-sliding mode control was derived. The RBF neural networks were used to approximate the discontinuous part of control gain in a classical sliding mode controller. Through the numerical simulation, the effectiveness of the sliding mode control methods was verified.The experiments on the dynamic properties and trajectory tracking control of the 2-DOF redundantly actuated parallel robots were carried out. Tests of vibration and frequency characteristic were finished. The electromechanical coupling dynamic model was verified by the symmetric trapezoidal trajectory tracking control experiment. On the basis of traditional PID http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets controller, velocity and acceleration feed-forward control was introduced to improve the trajectory tracking performance.The work of this dissertation will lay a solid foundation for further application study of redundantly actuated parallel robots, and will give reference to theory and application study of other types of parallel robots. This will help parallel robots operate with high quality.
Theoretical Analysis and Test Study on New Electro-mechanical Transformers Used in Electro-hydraulic Proportional Servo Valves
Theoretical Analysis and Test Study on New Electro-mechanical Transformers Used in Electro-hydraulic Proportional Servo Valves
Servo proportional components (including servo proportional valves and servo proportional pumps) are important hydraulic control components and widely used in every aspect of industrial and engineering automation. The ability to master the associated technology has a significant impact on national defense construction and equipment manufacturing. Currently, the technology is a holding back factor for our country to transform from a big manufacturing country to a manufacturing power. National long-term development plan, major projects are planning to adjust this technology as a key breakthrough. As the servo proportional component performance is largely determined Neodymium Magnets by the electrical-mechanical transformer performance, it has great significance for us to be in-depth study of electrical-mechanical transformer for national defense and equipment manufacturing industry. Being one aspect of the study of National Natural Science Foundation " Theories and Methods of New Concept Continuous Control on Electro-hydraulic Flow Rate and Direction " (50575156), this thesis focus on in-depth study of low-cost, high response, new structure of electrical- mechanical transformer and research methods for electrical-mechanical transformer. Proportional solenoids were researched theoretically. In order to take the advantage of high accuracy of finite element method (FEM) and advantage of rapid calculation ability of most simulation software, the FEM model of the key reluctance in proportional solenoid was established. Characteristic parameters of the FEM model were determined with FEM. By fitting the FEM calculation results, the formulas for calculating the key reluctance in proportional solenoid were obtained. The formulas were also validated with Simulation in MATLAB/SIMULINK and FEM software Ansoft.
This work laid the foundation for building the accurately proportional solenoid model in simulation software.A new scheme for electro-hydraulic proportional servo valves with on-off solenoids was proposed. A method of adaptive Feed Forward Compensator (AFFC) to correct static nonlinear characteristic of on-off solenoids is proposed based on close loop control. The settle time is shorten obviously by using Anti-Satuation Integral Control (ASIC) techniques, while the static error is held to zero. The principles of AFFC and ASIC are explained theoretically and tested in experiments. Moreover, we found that the transient time was even shorten when the gain of the close http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets feedback loop was increased in our scheme, The research results show that our scheme has the advantages of simply design and low price.In order to develop the fast response electro-mechanical transformer used to drive the pilot stage of large flow rate servo proportional valve, a novel structure of electro-mechanical transformer with shaped permanent magnet was proposed and its design principles were indicated. Magnetic circuit characteristics of the dedicated moving coil linear motor (MCLA) were studied with finite element method. The analysis indicated that MCLA’s driving force can be increased more than 7% by using shaped permanent magnet. A MCLA used to drive the pilot stage of large flow rate servo proportional valve was designed and the prototype was developed. The test system for small linear motor was built and the prototype was tested. The test results show that the performance of the prototype can meet the pilot driving requirement of fast response large flow rate servo proportional valve.A novel 2-degree-of-freedom electro-mechanical transformer (2-DOF EM) with two moving parts was proposed to meet the high speed response of electro-mechanical trans- former required by servo proportional valves.
The principle on which it decreased the response time of a servo proportional valve was explained. Several possible structures were introduced. The magnetic circuit of single-input dual-output EM (SIDO EM) was analyzed. Analysis indicated that SIDO EM can simultaneously drive the proportional valve spool and valve cover, and the valve opening is controlled. But the spool or valve cover cannot be controlled independently with SISO EM. The magnetic circuit of a hybrid two-input 2-DOF EM was analyzed, and its output characteristics in every case were derived with finite element method (FEM). Research results indicate that the 2-DOF EM can control the two linear moving parts simultaneously, drive them to move in the same or opposite direction independently. It can be used in the control of servo proportional valves and other equipments which have two linear moving parts.The application of proportional servo valve was studied. The starting of electro-hydraulic position servo system might cause the drop of the system pressure, actuator velocity fluctuation and hydraulic impact. The sudden drop of the pressure, if with more than one actuator in the system, would probably misact other actuators or even lead to grave accidents. Facing the problems, two solutions are proposed. One is to divide the position control procedure into a position control procedure and a velocity control procedure in which the maximum velocity of the actuator is restricted within the supply flow rate and the liquid compressibility. The other is to http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets adjust the flow rate at the servo valve by means of pressure difference of the chambers. These two methods are demonstrated theoretically and verified by digital simulation and experiments of an electro-hydraulic position servo system. It is finally proven that the sudden drop of the supply pressure and hydraulic impact during the starting of electro-hydraulic position servo system can be removed with the two new methods without influence upon the system response properties.
Servo proportional components (including servo proportional valves and servo proportional pumps) are important hydraulic control components and widely used in every aspect of industrial and engineering automation. The ability to master the associated technology has a significant impact on national defense construction and equipment manufacturing. Currently, the technology is a holding back factor for our country to transform from a big manufacturing country to a manufacturing power. National long-term development plan, major projects are planning to adjust this technology as a key breakthrough. As the servo proportional component performance is largely determined Neodymium Magnets by the electrical-mechanical transformer performance, it has great significance for us to be in-depth study of electrical-mechanical transformer for national defense and equipment manufacturing industry. Being one aspect of the study of National Natural Science Foundation " Theories and Methods of New Concept Continuous Control on Electro-hydraulic Flow Rate and Direction " (50575156), this thesis focus on in-depth study of low-cost, high response, new structure of electrical- mechanical transformer and research methods for electrical-mechanical transformer. Proportional solenoids were researched theoretically. In order to take the advantage of high accuracy of finite element method (FEM) and advantage of rapid calculation ability of most simulation software, the FEM model of the key reluctance in proportional solenoid was established. Characteristic parameters of the FEM model were determined with FEM. By fitting the FEM calculation results, the formulas for calculating the key reluctance in proportional solenoid were obtained. The formulas were also validated with Simulation in MATLAB/SIMULINK and FEM software Ansoft.
This work laid the foundation for building the accurately proportional solenoid model in simulation software.A new scheme for electro-hydraulic proportional servo valves with on-off solenoids was proposed. A method of adaptive Feed Forward Compensator (AFFC) to correct static nonlinear characteristic of on-off solenoids is proposed based on close loop control. The settle time is shorten obviously by using Anti-Satuation Integral Control (ASIC) techniques, while the static error is held to zero. The principles of AFFC and ASIC are explained theoretically and tested in experiments. Moreover, we found that the transient time was even shorten when the gain of the close http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets feedback loop was increased in our scheme, The research results show that our scheme has the advantages of simply design and low price.In order to develop the fast response electro-mechanical transformer used to drive the pilot stage of large flow rate servo proportional valve, a novel structure of electro-mechanical transformer with shaped permanent magnet was proposed and its design principles were indicated. Magnetic circuit characteristics of the dedicated moving coil linear motor (MCLA) were studied with finite element method. The analysis indicated that MCLA’s driving force can be increased more than 7% by using shaped permanent magnet. A MCLA used to drive the pilot stage of large flow rate servo proportional valve was designed and the prototype was developed. The test system for small linear motor was built and the prototype was tested. The test results show that the performance of the prototype can meet the pilot driving requirement of fast response large flow rate servo proportional valve.A novel 2-degree-of-freedom electro-mechanical transformer (2-DOF EM) with two moving parts was proposed to meet the high speed response of electro-mechanical trans- former required by servo proportional valves.
The principle on which it decreased the response time of a servo proportional valve was explained. Several possible structures were introduced. The magnetic circuit of single-input dual-output EM (SIDO EM) was analyzed. Analysis indicated that SIDO EM can simultaneously drive the proportional valve spool and valve cover, and the valve opening is controlled. But the spool or valve cover cannot be controlled independently with SISO EM. The magnetic circuit of a hybrid two-input 2-DOF EM was analyzed, and its output characteristics in every case were derived with finite element method (FEM). Research results indicate that the 2-DOF EM can control the two linear moving parts simultaneously, drive them to move in the same or opposite direction independently. It can be used in the control of servo proportional valves and other equipments which have two linear moving parts.The application of proportional servo valve was studied. The starting of electro-hydraulic position servo system might cause the drop of the system pressure, actuator velocity fluctuation and hydraulic impact. The sudden drop of the pressure, if with more than one actuator in the system, would probably misact other actuators or even lead to grave accidents. Facing the problems, two solutions are proposed. One is to divide the position control procedure into a position control procedure and a velocity control procedure in which the maximum velocity of the actuator is restricted within the supply flow rate and the liquid compressibility. The other is to http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets adjust the flow rate at the servo valve by means of pressure difference of the chambers. These two methods are demonstrated theoretically and verified by digital simulation and experiments of an electro-hydraulic position servo system. It is finally proven that the sudden drop of the supply pressure and hydraulic impact during the starting of electro-hydraulic position servo system can be removed with the two new methods without influence upon the system response properties.
2012年1月15日星期日
Research of Physical Targeting and Aggregation Behavior of the Paramagnetic Nanometer-Iron Nuclide(PNINs)
Research of Physical Targeting and Aggregation Behavior of the Paramagnetic Nanometer-Iron Nuclide(PNINs)
Objectives:To develop a new type of material-the paramagnetic nanometer-iron nuclides (PNINs) that can be used as both a source for targeted radiotherapy, and a carrier for targeted chemotherapy; to design an in-vitro system of rotating magnetic field as the guiding magnetic field to concentrate PNINs on the target area; to study theoretically and simulate numerically the transport properties and the targeting aggregation characteristics of the PNINs under the guiding magnetic field; to explore the physical target positioning system for targeted therapies of solid tumors with PNINs drugs, which could provide theoretical basis and technical parameters for clinical tumor therapy using PNINs.Methods:(1) The iron nanoparticles are prepared by chemical carbonyl method, and the Magnet lifter paramagnetic nanometer-iron nuclides (PNINs) are produced by irradiating the prepared iron nanoparticles with the pulsed-neutron reactor. (2)The intensities and gradient distributions are compared among the circular current magnetic field, the Helmholtz coil magnetic field, the cylindrical permanent magnetic field, the circular current magnetic field and the rotating magnetic field after adding magnetic materials. Theoretical models for the physical target positioning system of the PNINs in the static magnetic field (target) and in the rotating magnetic field (in vitro) are established and simulated numerically by using ANSYS software;
(3) Based on the force distribution on PNINs in the body, a theoretical model for PNINs in the target positioning system is established. Numerical simulation are carried out with MATHCAD procedure for the trajectory of PNINs carrying magnetic drugs in the rotating magnetic field; (4) The transport properties, accumulation characteristics and dynamic behavior of PNINs and drug-loaded PNIPs in the microvasculature under the guiding magnetic field are described, modelled and calculated.Results:(1) The radioactive nanometer-iron nuclides with average diameter less than 100nm are produced. The nanoparticles exhibite strong paramagnetism, radioactivity intensity and good magnetic delivery function and can be effectively positioned to the target area. (2) The magnetic field of the cylindrical permanent-magnet has the largest magnetic intensity and gradient among the three guiding magnetic fields. Addition of magnetic material into the cylindrical permanent-magnet can raise the magnetic field gradient and the aggregation of the PNINs within the target area, which is essential to targeted therapies. (3) The physical targeting system guided by the rotating magnetic field (in vitro) for the positioning of PNINs can avoid the injuries resulted from the establishment of the static magnetic field (target area). (4) The effects of the size of the magnetic drug particle, the PNINs content, the tumor depth, the http://www.999magnet.com/products/131-magnetic-lifter blood flow rate, the vessel diameter and other factors on the drug collection rate are obtained.Conclusions:PNINs and drug-loaded particles in target positioning system, including the in-vivo constant magnetic field and the in-vitro rotating magnetic field, can gather efficiently in the target area with excellent targeting ability. The effect of targeting aggregation can be evaluated quantitatively by calculating the collection rate of PNINs drugs and the coefficient of the capture cross section.
Objectives:To develop a new type of material-the paramagnetic nanometer-iron nuclides (PNINs) that can be used as both a source for targeted radiotherapy, and a carrier for targeted chemotherapy; to design an in-vitro system of rotating magnetic field as the guiding magnetic field to concentrate PNINs on the target area; to study theoretically and simulate numerically the transport properties and the targeting aggregation characteristics of the PNINs under the guiding magnetic field; to explore the physical target positioning system for targeted therapies of solid tumors with PNINs drugs, which could provide theoretical basis and technical parameters for clinical tumor therapy using PNINs.Methods:(1) The iron nanoparticles are prepared by chemical carbonyl method, and the Magnet lifter paramagnetic nanometer-iron nuclides (PNINs) are produced by irradiating the prepared iron nanoparticles with the pulsed-neutron reactor. (2)The intensities and gradient distributions are compared among the circular current magnetic field, the Helmholtz coil magnetic field, the cylindrical permanent magnetic field, the circular current magnetic field and the rotating magnetic field after adding magnetic materials. Theoretical models for the physical target positioning system of the PNINs in the static magnetic field (target) and in the rotating magnetic field (in vitro) are established and simulated numerically by using ANSYS software;
(3) Based on the force distribution on PNINs in the body, a theoretical model for PNINs in the target positioning system is established. Numerical simulation are carried out with MATHCAD procedure for the trajectory of PNINs carrying magnetic drugs in the rotating magnetic field; (4) The transport properties, accumulation characteristics and dynamic behavior of PNINs and drug-loaded PNIPs in the microvasculature under the guiding magnetic field are described, modelled and calculated.Results:(1) The radioactive nanometer-iron nuclides with average diameter less than 100nm are produced. The nanoparticles exhibite strong paramagnetism, radioactivity intensity and good magnetic delivery function and can be effectively positioned to the target area. (2) The magnetic field of the cylindrical permanent-magnet has the largest magnetic intensity and gradient among the three guiding magnetic fields. Addition of magnetic material into the cylindrical permanent-magnet can raise the magnetic field gradient and the aggregation of the PNINs within the target area, which is essential to targeted therapies. (3) The physical targeting system guided by the rotating magnetic field (in vitro) for the positioning of PNINs can avoid the injuries resulted from the establishment of the static magnetic field (target area). (4) The effects of the size of the magnetic drug particle, the PNINs content, the tumor depth, the http://www.999magnet.com/products/131-magnetic-lifter blood flow rate, the vessel diameter and other factors on the drug collection rate are obtained.Conclusions:PNINs and drug-loaded particles in target positioning system, including the in-vivo constant magnetic field and the in-vitro rotating magnetic field, can gather efficiently in the target area with excellent targeting ability. The effect of targeting aggregation can be evaluated quantitatively by calculating the collection rate of PNINs drugs and the coefficient of the capture cross section.
Experimental Investigations of Influence of Temperature Cycling and Lateral Moving Speed on Electromagnetic Forces in High-Temperature Superconductor Levitation Systems
Experimental Investigations of Influence of Temperature Cycling and Lateral Moving Speed on Electromagnetic Forces in High-Temperature Superconductor Levitation Systems
Owing to its higher upper critical magnetic field, higher critical current density and transition temperature above the temperature of liquid nitrogen, high temperature superconductor (HTS) shows some very important features in applications. The diamagnetic and flux pinning characteristics make high temperature superconducting levitation system has excellent loading capacity and novel passive stable characteristic. Thus the high temperature superconducting levitation system become an important branch of applications of superconductivity. The electromagnetic force characteristic researches on the typical superconducting levitation style, a superconductor and a permanent magnet (PM) levitation system, have become the basis of the superconducting levitating system operation design, Magnet lifter and a subject of considerable interest, which have been extensively investigated. This Ph. D. dissertation presents some experimental investigations of the static and dynamic electromagnetic force characteristics in the high temperature superconductor levitation system under some different temperature cyclings and lateral moving velocity conditions, some new phenomena and characteristics are found, and the results are explained; The frozen-image model is also modified to fit the experimental results of influences of lateral moving of permanent magnet on the electromagnetic forces.Firstly, the influences of different cooling temperature on the hysteretic curves of levitation force versus gap between the bulk HTS and the PM under zero-field cooling (ZFC) are described. It is found that with the decreasing of cooling temperature, there exists a crossing phenomenon on the hysteretic curves of levitation force. Even though the hysteresis loop area decreases with the decreasing of cooling temperature and the maximum levitation force of each hysteretic curves of different cooling temperature increase and saturate under lower cooling temperature condition, the crossing area and the gap of crossing point increase with the decreasing of cooling temperature.Secondly, the influences of some temperature cycling on the levitation force relaxation is described.
It is found that the levitation force continue to decrease when the temperature of superconductor is decreased continually from the initial cooling temperature during the relaxation, and it will increase with the increasing of temperature after the continual decreasing. According to these results, a temperature stabilization pretreatment method is presented. Another temperature cycling that increase the temperature from the initial cooling temperature under zero http://www.999magnet.com/products/131-magnetic-lifter magnetic field condition and then go back to the initial cooling temperature also under zero magnetic field condition will show a fixed ratio between the decreased levitation force ranges of increasing and decreasing processes if the target value of increasing process for different initial cooling temperature cases are the same.Finally, the effects of the initial cooling height (CH) and the lateral moving speed on the levitation force and the lateral force in the levitation system are described. The measurement results show that for some cooling height after the symmetrical movement (from the CH to levitation height) the effects of lateral movement and lateral moving velocity on the levitation force are remarkable. The levitation force will decrease for higher CH and increase for lower CH after the lateral movement. The hysteresis loop area of levitation force increase with the increasing of lateral moving velocity for higher CH, and the hysteresis loop area have nearly no change for lower CH. The hysteresis loop area of lateral force for all CH have nearly no change with the increasing of lateral moving velocity. The frozen-image method has also be modified to simulate the results of above, that the lateral moving speed has significant effect on levitation force-lateral displacement hysteresis loop curves.
Owing to its higher upper critical magnetic field, higher critical current density and transition temperature above the temperature of liquid nitrogen, high temperature superconductor (HTS) shows some very important features in applications. The diamagnetic and flux pinning characteristics make high temperature superconducting levitation system has excellent loading capacity and novel passive stable characteristic. Thus the high temperature superconducting levitation system become an important branch of applications of superconductivity. The electromagnetic force characteristic researches on the typical superconducting levitation style, a superconductor and a permanent magnet (PM) levitation system, have become the basis of the superconducting levitating system operation design, Magnet lifter and a subject of considerable interest, which have been extensively investigated. This Ph. D. dissertation presents some experimental investigations of the static and dynamic electromagnetic force characteristics in the high temperature superconductor levitation system under some different temperature cyclings and lateral moving velocity conditions, some new phenomena and characteristics are found, and the results are explained; The frozen-image model is also modified to fit the experimental results of influences of lateral moving of permanent magnet on the electromagnetic forces.Firstly, the influences of different cooling temperature on the hysteretic curves of levitation force versus gap between the bulk HTS and the PM under zero-field cooling (ZFC) are described. It is found that with the decreasing of cooling temperature, there exists a crossing phenomenon on the hysteretic curves of levitation force. Even though the hysteresis loop area decreases with the decreasing of cooling temperature and the maximum levitation force of each hysteretic curves of different cooling temperature increase and saturate under lower cooling temperature condition, the crossing area and the gap of crossing point increase with the decreasing of cooling temperature.Secondly, the influences of some temperature cycling on the levitation force relaxation is described.
It is found that the levitation force continue to decrease when the temperature of superconductor is decreased continually from the initial cooling temperature during the relaxation, and it will increase with the increasing of temperature after the continual decreasing. According to these results, a temperature stabilization pretreatment method is presented. Another temperature cycling that increase the temperature from the initial cooling temperature under zero http://www.999magnet.com/products/131-magnetic-lifter magnetic field condition and then go back to the initial cooling temperature also under zero magnetic field condition will show a fixed ratio between the decreased levitation force ranges of increasing and decreasing processes if the target value of increasing process for different initial cooling temperature cases are the same.Finally, the effects of the initial cooling height (CH) and the lateral moving speed on the levitation force and the lateral force in the levitation system are described. The measurement results show that for some cooling height after the symmetrical movement (from the CH to levitation height) the effects of lateral movement and lateral moving velocity on the levitation force are remarkable. The levitation force will decrease for higher CH and increase for lower CH after the lateral movement. The hysteresis loop area of levitation force increase with the increasing of lateral moving velocity for higher CH, and the hysteresis loop area have nearly no change for lower CH. The hysteresis loop area of lateral force for all CH have nearly no change with the increasing of lateral moving velocity. The frozen-image method has also be modified to simulate the results of above, that the lateral moving speed has significant effect on levitation force-lateral displacement hysteresis loop curves.
Study on Structural Dynamics Characteristics of a Lorentz Planar Motor
Study on Structural Dynamics Characteristics of a Lorentz Planar Motor
Lorentz planar motor is a novel permanent magnet planar driving system propelled by linear Lorentz force, which consists of three Lorentz linear motors (Y1、X and Y2). It can achieve 3 degree of freedom positioning, i.e. translation along the X and Y directions and rotation about Z axis, Rz. The positioning stage is drived directly by Lorentz planar motor. Some microvibrations from external or internal excitations will impact the positioning accuracy of the stage. Therefore, dynamic characteristic and normal vibration of Lorentz planar motor should be deeply researched. In the thesis, the Lorentz planar motor is our research object. Our research method is theoretical analysis, Magnet lifter numerical simulation and physical experiment. Some theories of structure dynamics, flexible mechanism and electromagnetic field are adopted. The normal electromagnetic parameters are identified using 3D finite element method and modal testing. The 3D electromagnetic finite element model, structural dynamic model and normal vibration model of Lorentz planar motor are achieved by numerical computing and physical experiment. Researches are focusing on the dynamic characteristic analysis and normal vibration transmission of the Lorentz planar motor. Contents and results as follows,Firstly, the 3D magnetic field in the airgap generated by permanent magnets and coils is derived by using the equivalent surface current method. The relations of sizes and positions of magnets and coils, surface magnetization current density and magnetic field of airgap are obtained. Magnetic flux linkage equations and mathematical model of Lorentz planar motor are established. Based on calculation and analysis of Lorentz forces, an electromagnetic dynamic model, which is ready for motion control in X, Y and Rz directions, is established. The normal vibration transmission between the stator and mover is illustrated. Normal vibration models of the stator and mover are built separately, which is used for obtaining the relations among structure deflections, electromagnetic forces and currents.Secondly, the normal electromagnetic stiffness is identified using 3D finite element method and modal testing.
The electromagnetic damping ratio is effectively identified by modal testings. According to the actual connections and constraints of Lorentz planar motor, structural dynamic finite element model of the planar motor system is established by adopting manually hexahedral mesh and loading equivalent normal electromagnetic springs. Based on structural finite element model, dynamic computation procedures are compiled and the structure dynamic characteristics are in-depth computed, including the normal frequencies, frequency response and transient response.Then, http://www.999magnet.com/products/131-magnetic-lifter in order to reveal some important parameters influencing on dynamic characteristics of Lorentz planar motor, we focus on analyzing the excitation current, Z-displacement and velocity in motion directions, which is a solid foundation for the motion control strategy and stuctural optimization of the Lorentz planar motor.Finally, a testing system of Lorentz planar motor has been set up, and the magnetic field in airgap and motor’s thrust constant by experiments are achieved. The distribution of airgap’s magnetic field by experiments verifies that 3D magnetic field simulation results are in good agreement with experimental results. The normal frequencies, model shape, frequency domain response and time domain response are obtained by modal testings using LMS system. Modal testing results verify that dynamic parameter identifications are accurate and structural finite element model is reasonable.In this dissertation, the dynamic characteristics of Lorentz planar motor are revealed, and the phenomenon of vibration transmission between stator and mover is clarified, and the methods of parameter identification of electromagnetic dynamics are proposed. These simulation models and methods will provide theoretical guidelines for mechanical structure design, optimization and control strategies, as well as the conclusions have been effective used in the research on the ultra-precision positioning stage.
Lorentz planar motor is a novel permanent magnet planar driving system propelled by linear Lorentz force, which consists of three Lorentz linear motors (Y1、X and Y2). It can achieve 3 degree of freedom positioning, i.e. translation along the X and Y directions and rotation about Z axis, Rz. The positioning stage is drived directly by Lorentz planar motor. Some microvibrations from external or internal excitations will impact the positioning accuracy of the stage. Therefore, dynamic characteristic and normal vibration of Lorentz planar motor should be deeply researched. In the thesis, the Lorentz planar motor is our research object. Our research method is theoretical analysis, Magnet lifter numerical simulation and physical experiment. Some theories of structure dynamics, flexible mechanism and electromagnetic field are adopted. The normal electromagnetic parameters are identified using 3D finite element method and modal testing. The 3D electromagnetic finite element model, structural dynamic model and normal vibration model of Lorentz planar motor are achieved by numerical computing and physical experiment. Researches are focusing on the dynamic characteristic analysis and normal vibration transmission of the Lorentz planar motor. Contents and results as follows,Firstly, the 3D magnetic field in the airgap generated by permanent magnets and coils is derived by using the equivalent surface current method. The relations of sizes and positions of magnets and coils, surface magnetization current density and magnetic field of airgap are obtained. Magnetic flux linkage equations and mathematical model of Lorentz planar motor are established. Based on calculation and analysis of Lorentz forces, an electromagnetic dynamic model, which is ready for motion control in X, Y and Rz directions, is established. The normal vibration transmission between the stator and mover is illustrated. Normal vibration models of the stator and mover are built separately, which is used for obtaining the relations among structure deflections, electromagnetic forces and currents.Secondly, the normal electromagnetic stiffness is identified using 3D finite element method and modal testing.
The electromagnetic damping ratio is effectively identified by modal testings. According to the actual connections and constraints of Lorentz planar motor, structural dynamic finite element model of the planar motor system is established by adopting manually hexahedral mesh and loading equivalent normal electromagnetic springs. Based on structural finite element model, dynamic computation procedures are compiled and the structure dynamic characteristics are in-depth computed, including the normal frequencies, frequency response and transient response.Then, http://www.999magnet.com/products/131-magnetic-lifter in order to reveal some important parameters influencing on dynamic characteristics of Lorentz planar motor, we focus on analyzing the excitation current, Z-displacement and velocity in motion directions, which is a solid foundation for the motion control strategy and stuctural optimization of the Lorentz planar motor.Finally, a testing system of Lorentz planar motor has been set up, and the magnetic field in airgap and motor’s thrust constant by experiments are achieved. The distribution of airgap’s magnetic field by experiments verifies that 3D magnetic field simulation results are in good agreement with experimental results. The normal frequencies, model shape, frequency domain response and time domain response are obtained by modal testings using LMS system. Modal testing results verify that dynamic parameter identifications are accurate and structural finite element model is reasonable.In this dissertation, the dynamic characteristics of Lorentz planar motor are revealed, and the phenomenon of vibration transmission between stator and mover is clarified, and the methods of parameter identification of electromagnetic dynamics are proposed. These simulation models and methods will provide theoretical guidelines for mechanical structure design, optimization and control strategies, as well as the conclusions have been effective used in the research on the ultra-precision positioning stage.
Research on HTS Maglev Continuous Pulsed Magnetic Traveling Wave Propulsion
Research on HTS Maglev Continuous Pulsed Magnetic Traveling Wave Propulsion
In the three types of electromagnetic launch, Reconnection gun combines the advantages of rail gun and coil gun, which can launch massive projectiles and achieve ultra-high speed. It is considered the best prospect type of electromagnetic launch. However, the levitation force provided by drive coils is interrelated with the amplitude of excitation current. When the drive coil excitation current is 0, the drive coil can not provide levitation force. So the assistant suspension device is need to ensure the stability suspended state of projectile, and don’t collide and rub with the drive coil. Superconducting Maglev electromagnetic launch technology has the characteristic of "great carrying capacity, a large suspension gap, friction-free, low power, low maintenance, safe and reliable, low pollution". It is an ideal method of launch. The core technologies of superconducting Maglev electromagnetic launch include magnetic levitation systems, propulsion systems and high power pulse power system.This paper firstly Magnet lifter analyzes the characteristics of three traditional permanent magnetic maglev rails. Halbach arrays rail could provide the highest surface magnetic field, levitation force and guidance force, but the internal structure is most unstable and hardest installation at the same time. So, the Horizontal Magnet rail is used widely at present. Combining the characteristics of magnetic field distribution of Halbach arrays, this paper designed a new type of magnetic levitation rail:advanced Halbach structure permanent magnetic maglev rail. This new type of levitation rail, not only retains the characteristics of Halbach structure to provide strong magnetic field, but also solved the problem of instability.In propulsion, aiming at the problem of the interval of two adjoining power excitation longer and effective acceleration time shorter in reconnection gun, this paper proposes a continuous pulsed magnetic traveling wave launch. It generates a continuous magnetic traveling wave in temporal and spatial. The projectile followed with the motion of magnetic traveling wave. The interval of excitation is shortened.
And the projectile could be quickly up to speed. From the principle of continuous pulsed magnetic traveling wave propulsion, the paper obtains two forms of driven coil layout suitable. The driven mode, requirement of drive current wave forms, requirement of pulse interface are discussed. The effect of continuous pulsed magnetic traveling wave propulsion is simulated and compared with the reconnection gun. Calculations show that continuous pulsed magnetic traveling wave propulsion can improve the emission rate, shorten the launch time, and increasing the emission efficiency. In the pulse power, capacitance energy storage has leakage current and can’t save energy with a long time; inductance energy storage should use breakers, and high voltage is easy to be produced during the energy releasing. Furthermore, the breakers are difficult to achieve great current and high http://www.999magnet.com/products/131-magnetic-lifter power. To solve these problems, this paper designs a modularization high-temperature superconductivity inductance pulse output circuit. This circuit uses superconducting inductive energy storage to increase the energy storage time and density, uses modular technology and pulse transformer to make up for the insufficient of breaker, and uses MOV to prevent over-voltage on the superconducting inductor. This article mainly discusses the output current waveform of a single module/multi-module. The Generator circuit of electromagnetic emission drive current is designed. And the circuit parameters of the matching problem are analyzed by simulation. Furthermore, the mutual inductance coupling among energy storage inductors in multi-module integration are analyzed and dealt with.Finally, the suspension system, propulsion system and pulse power system designed by this paper are assembled and simply experiment tested. The feasibility of HTS continuous pulse magnetic wave electromagnetic launch is verified.
In the three types of electromagnetic launch, Reconnection gun combines the advantages of rail gun and coil gun, which can launch massive projectiles and achieve ultra-high speed. It is considered the best prospect type of electromagnetic launch. However, the levitation force provided by drive coils is interrelated with the amplitude of excitation current. When the drive coil excitation current is 0, the drive coil can not provide levitation force. So the assistant suspension device is need to ensure the stability suspended state of projectile, and don’t collide and rub with the drive coil. Superconducting Maglev electromagnetic launch technology has the characteristic of "great carrying capacity, a large suspension gap, friction-free, low power, low maintenance, safe and reliable, low pollution". It is an ideal method of launch. The core technologies of superconducting Maglev electromagnetic launch include magnetic levitation systems, propulsion systems and high power pulse power system.This paper firstly Magnet lifter analyzes the characteristics of three traditional permanent magnetic maglev rails. Halbach arrays rail could provide the highest surface magnetic field, levitation force and guidance force, but the internal structure is most unstable and hardest installation at the same time. So, the Horizontal Magnet rail is used widely at present. Combining the characteristics of magnetic field distribution of Halbach arrays, this paper designed a new type of magnetic levitation rail:advanced Halbach structure permanent magnetic maglev rail. This new type of levitation rail, not only retains the characteristics of Halbach structure to provide strong magnetic field, but also solved the problem of instability.In propulsion, aiming at the problem of the interval of two adjoining power excitation longer and effective acceleration time shorter in reconnection gun, this paper proposes a continuous pulsed magnetic traveling wave launch. It generates a continuous magnetic traveling wave in temporal and spatial. The projectile followed with the motion of magnetic traveling wave. The interval of excitation is shortened.
And the projectile could be quickly up to speed. From the principle of continuous pulsed magnetic traveling wave propulsion, the paper obtains two forms of driven coil layout suitable. The driven mode, requirement of drive current wave forms, requirement of pulse interface are discussed. The effect of continuous pulsed magnetic traveling wave propulsion is simulated and compared with the reconnection gun. Calculations show that continuous pulsed magnetic traveling wave propulsion can improve the emission rate, shorten the launch time, and increasing the emission efficiency. In the pulse power, capacitance energy storage has leakage current and can’t save energy with a long time; inductance energy storage should use breakers, and high voltage is easy to be produced during the energy releasing. Furthermore, the breakers are difficult to achieve great current and high http://www.999magnet.com/products/131-magnetic-lifter power. To solve these problems, this paper designs a modularization high-temperature superconductivity inductance pulse output circuit. This circuit uses superconducting inductive energy storage to increase the energy storage time and density, uses modular technology and pulse transformer to make up for the insufficient of breaker, and uses MOV to prevent over-voltage on the superconducting inductor. This article mainly discusses the output current waveform of a single module/multi-module. The Generator circuit of electromagnetic emission drive current is designed. And the circuit parameters of the matching problem are analyzed by simulation. Furthermore, the mutual inductance coupling among energy storage inductors in multi-module integration are analyzed and dealt with.Finally, the suspension system, propulsion system and pulse power system designed by this paper are assembled and simply experiment tested. The feasibility of HTS continuous pulse magnetic wave electromagnetic launch is verified.
Study of Analysis, Design and Control on Novel Flux Switching Motor System
Study of Analysis, Design and Control on Novel Flux Switching Motor System
Flux Switching Motor (FSM) is a novel brushless double salient motor emerging in recent years. It has the same structure as SRM which has neither winding nor PM in the rotor. FSM has the advantages of rugged structure, easy manufacture and low cost, it is also suitable to operate at extreme high speed and adverse condition. The windings in FSM are electrified all the time as it works. Compared to SRM, FSM has higher copper-utilize ratio and require less kVA of the power converter because the excitation current component and armature current component has been separated absolutely. The vibration and noise of the motor are reduced by the unique operational electrified pattern, thus FSM has been seen as a good potential candidate drive system in the future. Flux weaken control can be easily achieved because the field current can be controlled when FSM is operated as Magnet lifter a generator.FSM has the advantages of low cost and simple control strategies because only the armature winding require controlled. It has high efficiency and very good speed-adjust performance which is very like traditional DC motors. FSM has found more and more applications in household appliance, power tools and automotive appliance.FSM is an electromagnetic appliance with complicated nonlinear characteristics. It has obvious edge and local saturation effect which is the same as other double salient motors. In addition, FSM generates electromagnetic torque depending on the closed-coupled field and armature winding.
As FSM works, all the windings in stator are electrified all the time, the DC magnetic field generated by field winding and the AC magnetic field generated by armature winding are closed coupled. Hence, the edge and saturation effect are more strategic with respect to the other double salient motors. FSM is a complicated electromagnetic appliance with unique nonlinear, variable structure and close coupled characteristics.The present research scope and depth which the experts and scholars deal with is very limited due to the short period during which FSM has been studied. In view of this, this paper studied FSM system with the emphasis of operation principle, mathematic model, performance analysis, electromagnetic parameters calculation, magnetic field analysis, dynamic simulation, machine design and control. A prototype motor was trial-manufactured to validate the theoretical analysis. The power converter and position detecting appliance of FSM was developed. The main contents of this paper are as follows:(1) Chapter 2 studied the operation principle, electrified pattern and electromagnetic characteristics of FSM, then illustrated the nonlinear, variable structure and close coupled characteristics. Based on Maxwell 2D, the magnetic field and electromagnetic parameters of FSM are calculated and analyzed. The work of this part provided a good reference to the knowledge of FSM.(2) http://www.999magnet.com/products/131-magnetic-lifter Normal nonlinear method which was used to analyze the double salient motors can not describe the unique nonlinear, variable structure and close coupled characteristics of FSM. In order to overcome the problems of simulation and modeling of FSM, this paper established the high rank continuous nonlinear inductance function of FSM. Based on this model and hybrid means of modeling, the Simulink model of FSM involving the machine and whole control system were established.
Then the numerical simulation were performed and the results were compared to that obtained by Time stepped Element Method (TSFE).(3) In chapter 5, the nonlinear variable structure equivalent magnetic circuit model was proposed which can describe the detailed poly phase coupling and nonlinear characteristics of FSM. The analytical expressions of permeability in the air gap and iron core are deduced. During the calculation, the iteration and convergence process was studied and a method to determine the iteration coefficients is proposed to save the calculation time. The work of this part provides a powerful tool for the electromagnetic calculation of FSM.(4) In chapter 6, a novel numerical solving method aiming to simulate the dynamic performance of FSM rapidly and accurately was proposed based on modified Forward Euler method. This method set up the status equations of FSM by matrix re-transforming and advanced the modified forward Euler equation to the FSM dynamic performance calculation which faced the difficulties of differential inversion. The method has the merits of simple process and rapidity calculation. At last, the method above was employed to calculate the dynamic performance of FSM. The calculation results were compared to that obtained by four order Runge-Kutta method and TSFE, respectively. The work of this part provided a new effective approach to the dynamic performance calculation of FSM.(5) In chapter 7, the starting performance of FSM was studied and a variety of strategies focused on reducing the dead zone of starting were discussed. Some conclusions were drawn. At last, the approach for solving the starting problem of FSM was given.(6) In chapter 7, the equation of universal output power which was directly related to motor dimensions was deduced and the method to determine the stack length and number of coils was given.
The iteration calculation process of machine design was proposed. The optical rotor position detecting appliance and power converter of FSM were designed and developed. The experiment was implemented to study the performance of the prototype motor.(7) In chapter 8, the cogging torque in PMFSM was studied particularly. The detailed structure and principle of PMFSM are different from traditional PM motors and the principle, characteristics of cogging torque in PMFSM are also very different from traditional PM motors. This paper proposed an analytical theory for analyzing and calculating the cogging torque in PMFSM. Based on this theory, the analytical model of cogging torque which was directly related to the design parameters of PMFSM was deduced and employed to study the approaches to reducing cogging toque in PMFSM. At last, the detailed approach for reducing cogging torque was given which has important instructive significance to engineering practice in designing high performance PMFSM. (8) In chapter 9, a novel Hybrid Excitation Flux Switching Motor (HEFSM) was proposed and studied. FSM with electrified excitation has drawbacks of high level field current and high copper loss which limit the efficiency increasing. PMFSM has very narrow speed-adjustment range as a result of the uncontrolled magnetic motive force in PM as a motor. Besides, it is hard to adjust the output voltage when PMFSM work as a generator. Aiming at the drawbacks of present patterns of FSM, this paper proposed a novel Hybrid Excitation Flux Switching Motor. In HEFSM, the PMs were housed in the stator at special way. The magnetic field were generated both by PMs and armature winding, the speed-adjustment range could be widened by this proposed structure. HEFSM combined the merits of FSM with electrified excitation and PMFSM. The work in this part explored a new research frontier for FSM.
Flux Switching Motor (FSM) is a novel brushless double salient motor emerging in recent years. It has the same structure as SRM which has neither winding nor PM in the rotor. FSM has the advantages of rugged structure, easy manufacture and low cost, it is also suitable to operate at extreme high speed and adverse condition. The windings in FSM are electrified all the time as it works. Compared to SRM, FSM has higher copper-utilize ratio and require less kVA of the power converter because the excitation current component and armature current component has been separated absolutely. The vibration and noise of the motor are reduced by the unique operational electrified pattern, thus FSM has been seen as a good potential candidate drive system in the future. Flux weaken control can be easily achieved because the field current can be controlled when FSM is operated as Magnet lifter a generator.FSM has the advantages of low cost and simple control strategies because only the armature winding require controlled. It has high efficiency and very good speed-adjust performance which is very like traditional DC motors. FSM has found more and more applications in household appliance, power tools and automotive appliance.FSM is an electromagnetic appliance with complicated nonlinear characteristics. It has obvious edge and local saturation effect which is the same as other double salient motors. In addition, FSM generates electromagnetic torque depending on the closed-coupled field and armature winding.
As FSM works, all the windings in stator are electrified all the time, the DC magnetic field generated by field winding and the AC magnetic field generated by armature winding are closed coupled. Hence, the edge and saturation effect are more strategic with respect to the other double salient motors. FSM is a complicated electromagnetic appliance with unique nonlinear, variable structure and close coupled characteristics.The present research scope and depth which the experts and scholars deal with is very limited due to the short period during which FSM has been studied. In view of this, this paper studied FSM system with the emphasis of operation principle, mathematic model, performance analysis, electromagnetic parameters calculation, magnetic field analysis, dynamic simulation, machine design and control. A prototype motor was trial-manufactured to validate the theoretical analysis. The power converter and position detecting appliance of FSM was developed. The main contents of this paper are as follows:(1) Chapter 2 studied the operation principle, electrified pattern and electromagnetic characteristics of FSM, then illustrated the nonlinear, variable structure and close coupled characteristics. Based on Maxwell 2D, the magnetic field and electromagnetic parameters of FSM are calculated and analyzed. The work of this part provided a good reference to the knowledge of FSM.(2) http://www.999magnet.com/products/131-magnetic-lifter Normal nonlinear method which was used to analyze the double salient motors can not describe the unique nonlinear, variable structure and close coupled characteristics of FSM. In order to overcome the problems of simulation and modeling of FSM, this paper established the high rank continuous nonlinear inductance function of FSM. Based on this model and hybrid means of modeling, the Simulink model of FSM involving the machine and whole control system were established.
Then the numerical simulation were performed and the results were compared to that obtained by Time stepped Element Method (TSFE).(3) In chapter 5, the nonlinear variable structure equivalent magnetic circuit model was proposed which can describe the detailed poly phase coupling and nonlinear characteristics of FSM. The analytical expressions of permeability in the air gap and iron core are deduced. During the calculation, the iteration and convergence process was studied and a method to determine the iteration coefficients is proposed to save the calculation time. The work of this part provides a powerful tool for the electromagnetic calculation of FSM.(4) In chapter 6, a novel numerical solving method aiming to simulate the dynamic performance of FSM rapidly and accurately was proposed based on modified Forward Euler method. This method set up the status equations of FSM by matrix re-transforming and advanced the modified forward Euler equation to the FSM dynamic performance calculation which faced the difficulties of differential inversion. The method has the merits of simple process and rapidity calculation. At last, the method above was employed to calculate the dynamic performance of FSM. The calculation results were compared to that obtained by four order Runge-Kutta method and TSFE, respectively. The work of this part provided a new effective approach to the dynamic performance calculation of FSM.(5) In chapter 7, the starting performance of FSM was studied and a variety of strategies focused on reducing the dead zone of starting were discussed. Some conclusions were drawn. At last, the approach for solving the starting problem of FSM was given.(6) In chapter 7, the equation of universal output power which was directly related to motor dimensions was deduced and the method to determine the stack length and number of coils was given.
The iteration calculation process of machine design was proposed. The optical rotor position detecting appliance and power converter of FSM were designed and developed. The experiment was implemented to study the performance of the prototype motor.(7) In chapter 8, the cogging torque in PMFSM was studied particularly. The detailed structure and principle of PMFSM are different from traditional PM motors and the principle, characteristics of cogging torque in PMFSM are also very different from traditional PM motors. This paper proposed an analytical theory for analyzing and calculating the cogging torque in PMFSM. Based on this theory, the analytical model of cogging torque which was directly related to the design parameters of PMFSM was deduced and employed to study the approaches to reducing cogging toque in PMFSM. At last, the detailed approach for reducing cogging torque was given which has important instructive significance to engineering practice in designing high performance PMFSM. (8) In chapter 9, a novel Hybrid Excitation Flux Switching Motor (HEFSM) was proposed and studied. FSM with electrified excitation has drawbacks of high level field current and high copper loss which limit the efficiency increasing. PMFSM has very narrow speed-adjustment range as a result of the uncontrolled magnetic motive force in PM as a motor. Besides, it is hard to adjust the output voltage when PMFSM work as a generator. Aiming at the drawbacks of present patterns of FSM, this paper proposed a novel Hybrid Excitation Flux Switching Motor. In HEFSM, the PMs were housed in the stator at special way. The magnetic field were generated both by PMs and armature winding, the speed-adjustment range could be widened by this proposed structure. HEFSM combined the merits of FSM with electrified excitation and PMFSM. The work in this part explored a new research frontier for FSM.
2012年1月13日星期五
Research on Magnetic Suspension Flywheel Electric Machine for Energy Storage and Control of Drive System
Research on Magnetic Suspension Flywheel Electric Machine for Energy Storage and Control of Drive System
Flywheel energy storage system is a kind of novel electromechanical energy conversion device with several advantages, including long-life, high efficiency, strong adaptablility and no pollution etc. There is extensive application foreground in mang fields, such as aerospace, distributed electricity generation, electric power peak adjustion, and electromotion vehicle so on. Flywheel energy storage technology is a kind of cross technology with several high and new technology, including magnetic suspension technology, high speed electric machine technology, vacuum technology, power electronics technology and composite material technology etc., and it is deemed to be one Magnet lifter of the most valuable energy storage technology, so, the relative study content is very abundant. The research task of this paper comes from the Key Science and Technology Research Project of Shenzhen City Government——Early Research of Distributed Self-determination Energy System, and the main study contents of this paper include three parts: magnetic suspension bearing, motor/generator for flywheel energy storage(flywheel electric machine for energy storage) and control of flywheel electric machine drive system for energy storage.Magnetic suspension bearing technology is one of the key technologies of flywheel energy storage. This project proposes full passive magnetic suspension bearing structure which consisits of axial permanent-magnet suspension bearing and radial passive electromotive magnetic suspension bearing to remove abrasion and lubrication of traditional bearing. Axial permanent-magnet bearing is used to support the mass of flywheel rotor, radial passive electromotive magnetic bearing is used to keep radial stable suspension of flywheel.
There are many delightful research achievements of passive electromotive magnetic bearing in linear-motion occasion, but the research of passive electromotive magnetic bearing is in initial starting stage in rotating occasion, and it is a difficult point of magnetic bearing field. This paper proposes a new stucture of passive electromotive magnetic bearing which inclues two parts: stator supplys repulsive magnetic field, and rotor selects single-layer 8-shape coil http://www.999magnet.com/products/131-magnetic-lifter structure or double-layer 8-shape coil structure. And then several contents which include characteristics of repulsive magnetic field, force of 8-shape coil, force of rotor, and stabilization of bearing etc., are studied with theoretical analysis scheme and finite element analysis(FEA) scheme. Finally, a prototype and a test device for radial passive electromotive magnetic bearing is designed to validate theory analysis and simulation study; this device can assemble rotor to implement high speed rotation, conveniently observe movement process of stator, and measure the relative data between departure length and force of stator.Flywheel electric machine for energy storage which is the carrier of energy between electrical energy and mechanical energy is another key part of flywheel energy storage. Ironless permanent magnet square-wave flywheel electric machine is selected in this paper to improve some characteristics of energy storage system, such as efficiency, integration level etc. This type of electric machine has no copper loss of rotor and no iron loss of stator, so, the main loss is winding eddy loss without load, and the main loss includes winding loss and rotor eddy loss with full load. Theory estimation calculation model is modeled to reduce winding eddy loss, and the winding eddy loss of a prototype is estimated with the proposed model, finally validated by experiment of free halt. The rotor eddy loss maily comes from armature reaction, and the field resolution scheme is proposed using equivalent current layer which includes inner layer and outer layer to get the distribution of armature reaction field; to reduce rotor eddy loss and obtain high efficiency, the principle of loss caused by space harmonics and time harmonics is analyzed in detail, then, a experimental scheme to measure rotor eddy loss by changing windage loss is propsed, and the experiment results compare with FEA calculation results to validate the proposed experiment scheme, furthermore, the reliability of FEA calculation is also demonstrated.During the charge period, ironless permanent magnet square-wave brushless electric machine is difficult to drive because the little phase-inductance causes large steady-state current ripple with PWM control scheme; furthermore, large phase-conversion current ripple will be produced while the motor/generator is driven by square-wave control scheme.
So, the large steady-state current ripple and large phase-conversion current ripple will increase the control difficulty. This paper proposes a novel control scheme including double-frequency PWM(pulse width modulation) square-wave control and DC voltage adjustion to reduce steady-state current ripple, and the proposed scheme is validated by Matlab simulation and experiment. Then, novel three-phase inverter and bus current detecting shceme which are to obtain all current information are proposed to reduce phase-conversion current ripple of square-wave motor, and the proposed scheme is also validated by Matlab simulation and experiment. During the discharge period, the output voltage decreases with the speed of electric machine, which increases the control http://www.999magnet.com/products/131-magnetic-lifter difficulty for discharge. So, a converter for discharge which includes a Boost circuit and a single-phase inverter circuit is presented to obtain stable and safety output, and the proposed scheme is also validated by Matlab simulation.Finally, a digital minimum drive system for electric machine drive of flywheel energy storage based on TMS320F2812 DSP is designed. To satisfy control requirement of flywheel energy storage system, this paper mainly introduces hardware design and software design, and experimental research of flywheel energy storage system prototype is implemented with the minimum system, then experimental results compare with simulation results to validate practicability of system control scheme.
Flywheel energy storage system is a kind of novel electromechanical energy conversion device with several advantages, including long-life, high efficiency, strong adaptablility and no pollution etc. There is extensive application foreground in mang fields, such as aerospace, distributed electricity generation, electric power peak adjustion, and electromotion vehicle so on. Flywheel energy storage technology is a kind of cross technology with several high and new technology, including magnetic suspension technology, high speed electric machine technology, vacuum technology, power electronics technology and composite material technology etc., and it is deemed to be one Magnet lifter of the most valuable energy storage technology, so, the relative study content is very abundant. The research task of this paper comes from the Key Science and Technology Research Project of Shenzhen City Government——Early Research of Distributed Self-determination Energy System, and the main study contents of this paper include three parts: magnetic suspension bearing, motor/generator for flywheel energy storage(flywheel electric machine for energy storage) and control of flywheel electric machine drive system for energy storage.Magnetic suspension bearing technology is one of the key technologies of flywheel energy storage. This project proposes full passive magnetic suspension bearing structure which consisits of axial permanent-magnet suspension bearing and radial passive electromotive magnetic suspension bearing to remove abrasion and lubrication of traditional bearing. Axial permanent-magnet bearing is used to support the mass of flywheel rotor, radial passive electromotive magnetic bearing is used to keep radial stable suspension of flywheel.
There are many delightful research achievements of passive electromotive magnetic bearing in linear-motion occasion, but the research of passive electromotive magnetic bearing is in initial starting stage in rotating occasion, and it is a difficult point of magnetic bearing field. This paper proposes a new stucture of passive electromotive magnetic bearing which inclues two parts: stator supplys repulsive magnetic field, and rotor selects single-layer 8-shape coil http://www.999magnet.com/products/131-magnetic-lifter structure or double-layer 8-shape coil structure. And then several contents which include characteristics of repulsive magnetic field, force of 8-shape coil, force of rotor, and stabilization of bearing etc., are studied with theoretical analysis scheme and finite element analysis(FEA) scheme. Finally, a prototype and a test device for radial passive electromotive magnetic bearing is designed to validate theory analysis and simulation study; this device can assemble rotor to implement high speed rotation, conveniently observe movement process of stator, and measure the relative data between departure length and force of stator.Flywheel electric machine for energy storage which is the carrier of energy between electrical energy and mechanical energy is another key part of flywheel energy storage. Ironless permanent magnet square-wave flywheel electric machine is selected in this paper to improve some characteristics of energy storage system, such as efficiency, integration level etc. This type of electric machine has no copper loss of rotor and no iron loss of stator, so, the main loss is winding eddy loss without load, and the main loss includes winding loss and rotor eddy loss with full load. Theory estimation calculation model is modeled to reduce winding eddy loss, and the winding eddy loss of a prototype is estimated with the proposed model, finally validated by experiment of free halt. The rotor eddy loss maily comes from armature reaction, and the field resolution scheme is proposed using equivalent current layer which includes inner layer and outer layer to get the distribution of armature reaction field; to reduce rotor eddy loss and obtain high efficiency, the principle of loss caused by space harmonics and time harmonics is analyzed in detail, then, a experimental scheme to measure rotor eddy loss by changing windage loss is propsed, and the experiment results compare with FEA calculation results to validate the proposed experiment scheme, furthermore, the reliability of FEA calculation is also demonstrated.During the charge period, ironless permanent magnet square-wave brushless electric machine is difficult to drive because the little phase-inductance causes large steady-state current ripple with PWM control scheme; furthermore, large phase-conversion current ripple will be produced while the motor/generator is driven by square-wave control scheme.
So, the large steady-state current ripple and large phase-conversion current ripple will increase the control difficulty. This paper proposes a novel control scheme including double-frequency PWM(pulse width modulation) square-wave control and DC voltage adjustion to reduce steady-state current ripple, and the proposed scheme is validated by Matlab simulation and experiment. Then, novel three-phase inverter and bus current detecting shceme which are to obtain all current information are proposed to reduce phase-conversion current ripple of square-wave motor, and the proposed scheme is also validated by Matlab simulation and experiment. During the discharge period, the output voltage decreases with the speed of electric machine, which increases the control http://www.999magnet.com/products/131-magnetic-lifter difficulty for discharge. So, a converter for discharge which includes a Boost circuit and a single-phase inverter circuit is presented to obtain stable and safety output, and the proposed scheme is also validated by Matlab simulation.Finally, a digital minimum drive system for electric machine drive of flywheel energy storage based on TMS320F2812 DSP is designed. To satisfy control requirement of flywheel energy storage system, this paper mainly introduces hardware design and software design, and experimental research of flywheel energy storage system prototype is implemented with the minimum system, then experimental results compare with simulation results to validate practicability of system control scheme.
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