题名:连续掺镱光子晶体光纤激光器理论和实验研究
作者:左伟丽
学位授予单位:郑州大学
关键词:掺镱光子晶体光纤激光器;;传输特性;;输出特性;;冷却
摘要:
光子晶体光纤可以实现大模场面积、内包层大数值孔径、高掺杂稀土乃至多芯设计,从而有效降低了光纤激光器高功率运转时的非线性效应和热效应,还能保持良好的光束质量,解决了常规光纤激光器存在的无法解决的问题,显示出了这个新生事物的广阔发展前景和应用市场。本文从理论和实验两方面对掺Yb3+光子晶体光纤激光器进行系统的研究。主要内容如下：
1.简单介绍了掺镱光子晶体光纤激光器的特点,接着对国外和国内掺yb3+光子晶体光纤激光器的研究进展、主要应用和发展方向进Strong magnets行了综述,最后概述了本文的研究内容。
2.简要阐述了掺Yb3+光子晶体光纤激光器的基本理论；描述了Yb3+离子的能级结构、光谱特性以及受激辐射的特点；对光子晶体光纤的导光机理以及折射率引导型光子晶体光纤的特性和优点进行了系统的归纳和阐述。
3.建立了掺Yb3+光子晶体光纤激光器的理论模型。首先从麦克斯韦方程组导出的波动方程推导出光在光纤中的传输特性,并根据推导出的结论,利用comsol软件模拟出了光波在传输过程中基模模式的分布；接着,根据速率方程理论推导出了光子晶体光纤激光器的功率传输方程,并用MATLAB进行了数值模拟,进一步探讨了激光和泵浦光的功率分布、阈值、增益介质的长度、斜效率、输出透过率以及泵浦方式对激光输出的影响。为实验的优化设计提供了理论上的依据。
4.对F-P腔掺Yb3+光子晶体光纤http://www.chinamagnets.biz/激光器进行了实验研究。获得了26.4W的激光输出,耦合效率为41.3%,斜率效率为44%。对实验结果和实验中影响激光器的因素进行了合理的分析,提出今后工作的构想和建议。
学位年度:2010
2012年1月31日星期二
静磁场影响机体微循环系统的初步机理研究
题名:静磁场影响机体微循环系统的初步机理研究
作者:闫一力
学位授予单位:第四军医大学
关键词:静磁场;;微循环;;有限元分析;;连续小波变换频谱分析
摘要:
磁场是否能治疗疾病?这个古老而又悬而未决的话题一直困扰科学界多年,依然没有定论;同时,随着磁疗技术和仪器在临床上的广泛应用,回答磁场是否会对人体产生不良影响这个问题就显得非常紧迫。
静磁场对机体微循环系统的影响研究作为磁场生物效应的一个重要分支,日益受到广泛重视。根据对国内外文献的回顾,本文综述了该领域复杂的研究现状,分析了该领域经常出现复杂矛盾和尚不明朗的实验结果的潜在原因。rare earth magnets通过建立磁场的计算机仿真模型,进一步进行磁场对动物和人体微循环的影响实验,采用激光多普勒技术和连续小波变换技术评估了磁场暴露后局部微循环的指标的改变情况,初步探讨了磁场对机体微循环系统影响的机理,以期对该领域的进一步研究提供新的方向。
主要工作概括如下:
一、首次利用Comsol Multiphysics 3.4软件系统模拟了钕铁硼型磁片及磁片组、螺线管型交变电磁场和脉冲电磁场的三维时空分布,很好的弥补了传统磁场生物效应实验中对电磁场的理论分析不够直观和形象的缺点。通过统计和数值分析方法对仿真结果与实际测量数据进行对比分析,证实模拟结果精确度高,可以作为对实测结果和理论分析的很好的补充。在计算精度要求不是很高的情况下,甚至可以代替理论分析进行计算,为一些不规则复杂磁场的分布问题提供了很好的解决方案。
二、采用上表面中心强度约为220mT的静磁场(较小尺寸)对正常小鼠耳廓微循环进行30min短时暴露,发现在暴露中期和暴露后期,该尺寸和强度的静磁场未对小鼠耳廓微循环的血流量产生明显影响。关于该强度和该部位的研究国内外未见报道。
三、采用了基于连续小波频谱http://www.chinamagnets.biz/分析的新技术来评估上表面中心强度约为220mT的静磁场(较大尺寸)30min短期暴露对正常青年甲襞微循环系统的影响。结果发现,在暴露中期,磁场可能会引起血管平滑肌肌源性活动、外周神经系统的活动和内皮相关的代谢活动的增强(P<0.05),而整体的血流量的均值没有显著性变化(P>0.05),仍然保持在基值附近。此外,撤掉磁场之后,静磁场暴露中期出现的血流的节律变化逐渐消失,说明该强度静磁场对人体微循环系统影响的延迟作用并不明显。首次结合电磁屏蔽技术和小波频谱分析对局部微血流的无创实时监控技术研究磁场对人体微循环的影响,同时首次通过活体实验验证了磁场可能会潜在地影响正常人体的微循环调控通路,为该领域的进一步深入研究提供新的评估手段和思路。
学位年度:2010
作者:闫一力
学位授予单位:第四军医大学
关键词:静磁场;;微循环;;有限元分析;;连续小波变换频谱分析
摘要:
磁场是否能治疗疾病?这个古老而又悬而未决的话题一直困扰科学界多年,依然没有定论;同时,随着磁疗技术和仪器在临床上的广泛应用,回答磁场是否会对人体产生不良影响这个问题就显得非常紧迫。
静磁场对机体微循环系统的影响研究作为磁场生物效应的一个重要分支,日益受到广泛重视。根据对国内外文献的回顾,本文综述了该领域复杂的研究现状,分析了该领域经常出现复杂矛盾和尚不明朗的实验结果的潜在原因。rare earth magnets通过建立磁场的计算机仿真模型,进一步进行磁场对动物和人体微循环的影响实验,采用激光多普勒技术和连续小波变换技术评估了磁场暴露后局部微循环的指标的改变情况,初步探讨了磁场对机体微循环系统影响的机理,以期对该领域的进一步研究提供新的方向。
主要工作概括如下:
一、首次利用Comsol Multiphysics 3.4软件系统模拟了钕铁硼型磁片及磁片组、螺线管型交变电磁场和脉冲电磁场的三维时空分布,很好的弥补了传统磁场生物效应实验中对电磁场的理论分析不够直观和形象的缺点。通过统计和数值分析方法对仿真结果与实际测量数据进行对比分析,证实模拟结果精确度高,可以作为对实测结果和理论分析的很好的补充。在计算精度要求不是很高的情况下,甚至可以代替理论分析进行计算,为一些不规则复杂磁场的分布问题提供了很好的解决方案。
二、采用上表面中心强度约为220mT的静磁场(较小尺寸)对正常小鼠耳廓微循环进行30min短时暴露,发现在暴露中期和暴露后期,该尺寸和强度的静磁场未对小鼠耳廓微循环的血流量产生明显影响。关于该强度和该部位的研究国内外未见报道。
三、采用了基于连续小波频谱http://www.chinamagnets.biz/分析的新技术来评估上表面中心强度约为220mT的静磁场(较大尺寸)30min短期暴露对正常青年甲襞微循环系统的影响。结果发现,在暴露中期,磁场可能会引起血管平滑肌肌源性活动、外周神经系统的活动和内皮相关的代谢活动的增强(P<0.05),而整体的血流量的均值没有显著性变化(P>0.05),仍然保持在基值附近。此外,撤掉磁场之后,静磁场暴露中期出现的血流的节律变化逐渐消失,说明该强度静磁场对人体微循环系统影响的延迟作用并不明显。首次结合电磁屏蔽技术和小波频谱分析对局部微血流的无创实时监控技术研究磁场对人体微循环的影响,同时首次通过活体实验验证了磁场可能会潜在地影响正常人体的微循环调控通路,为该领域的进一步深入研究提供新的评估手段和思路。
学位年度:2010
杏优新品种的花果管理技术研究
题名:杏优新品种的花果管理技术研究
作者:张春波
学位授予单位:中国农业科学院
关键词:杏;;优新品种;;花果管理
摘要:
本文以辽宁省果树科学研究所已选育或引进的极早熟品种‘骆驼黄杏’、极晚熟品种‘串枝红杏’及仁用杏新品种‘国仁’和‘丰仁’为试材,调查分析各品种的落花落果和果实发育动态规律,制定有效的保花保果技术措施,从而确定仁用杏的适宜采收期；通过对不同品种N、P、K肥料施用量及施用时期的研究,Strong magnets进一步确定杏专用复合肥的最适施用量及施用时期,为掌握该优新品种的栽培习性和进一步推广栽培,提供理论指导和科学依据。现将主要结果简述如下：
1、落花落果规律调查结果表明,杏不同品种落花落果均出现两次高峰,第一次高峰在终花期,第二次高峰在幼果形成期,分别出现在花后4～8d和22～25d。‘骆驼黄杏’分别于盛花后第4d和22d出现落花高峰和落果高峰；‘丰仁杏’‘国仁杏’‘串枝红杏’分别于盛花后6～7d和24～25d出现落果高峰和落花高峰。
2、花期喷施外源激素和营养元素对鲜食杏和仁用杏的坐果率的影响表明,鲜食杏(‘骆驼黄杏’‘串枝红杏’)以50mg/L赤霉素和1200倍稀土处理效果最佳,坐果率分别为19.9%和19.6%；而仁用杏(‘国仁’‘丰仁’)花期喷施0.3%的磷酸二氢钾溶液坐果率最高,坐果率分别为25.5%和21.9%。
3、果实发育规律动态调查发现,杏在整个发育过程中均出现两次生长高峰,分别为快速生长期和缓慢生长期。
4、仁用杏的适宜采收期的确定研究表明,仁用杏果实生长分二个时期,即果实迅速生长期和果实缓慢生长期,且第二个时期时间http://www.chinamagnets.biz/较长,历时63d,是核仁生长的关键时期；仁用杏出仁率调查,‘丰仁杏’和‘国仁杏’盛花后98d采收,出仁率分别为37.5%和31.8%,出仁率最高,明显高于其它采收时间,是采收的最佳时期。
5、杏专用肥施用量研究结果表明,各处理均以株施2.25kg的果实和叶片理化指标最高,‘骆驼黄杏’产量比株施1kg(对照)增产116.9%,且‘国仁杏’的杏仁蛋白质、脂肪含量最高,分别比对照高2.572%、3.349%,也明显高于其他施肥量处理。
6、杏专用肥适宜施肥时期研究结果表明,‘丰仁杏’春秋两次施肥(春1/3、秋2/3)明显高于春施、夏施和秋施处理。‘丰仁杏’春秋两次施肥叶片中的N、P2O5、K2O、Ca、Mg含量、果仁产量、杏仁蛋白质、脂肪含量分别为2.74%、0.435%、1.47%、1.89%、74mg/kg、87.2g、24.4%、53.2%。
学位年度:2010
作者:张春波
学位授予单位:中国农业科学院
关键词:杏;;优新品种;;花果管理
摘要:
本文以辽宁省果树科学研究所已选育或引进的极早熟品种‘骆驼黄杏’、极晚熟品种‘串枝红杏’及仁用杏新品种‘国仁’和‘丰仁’为试材,调查分析各品种的落花落果和果实发育动态规律,制定有效的保花保果技术措施,从而确定仁用杏的适宜采收期；通过对不同品种N、P、K肥料施用量及施用时期的研究,Strong magnets进一步确定杏专用复合肥的最适施用量及施用时期,为掌握该优新品种的栽培习性和进一步推广栽培,提供理论指导和科学依据。现将主要结果简述如下：
1、落花落果规律调查结果表明,杏不同品种落花落果均出现两次高峰,第一次高峰在终花期,第二次高峰在幼果形成期,分别出现在花后4～8d和22～25d。‘骆驼黄杏’分别于盛花后第4d和22d出现落花高峰和落果高峰；‘丰仁杏’‘国仁杏’‘串枝红杏’分别于盛花后6～7d和24～25d出现落果高峰和落花高峰。
2、花期喷施外源激素和营养元素对鲜食杏和仁用杏的坐果率的影响表明,鲜食杏(‘骆驼黄杏’‘串枝红杏’)以50mg/L赤霉素和1200倍稀土处理效果最佳,坐果率分别为19.9%和19.6%；而仁用杏(‘国仁’‘丰仁’)花期喷施0.3%的磷酸二氢钾溶液坐果率最高,坐果率分别为25.5%和21.9%。
3、果实发育规律动态调查发现,杏在整个发育过程中均出现两次生长高峰,分别为快速生长期和缓慢生长期。
4、仁用杏的适宜采收期的确定研究表明,仁用杏果实生长分二个时期,即果实迅速生长期和果实缓慢生长期,且第二个时期时间http://www.chinamagnets.biz/较长,历时63d,是核仁生长的关键时期；仁用杏出仁率调查,‘丰仁杏’和‘国仁杏’盛花后98d采收,出仁率分别为37.5%和31.8%,出仁率最高,明显高于其它采收时间,是采收的最佳时期。
5、杏专用肥施用量研究结果表明,各处理均以株施2.25kg的果实和叶片理化指标最高,‘骆驼黄杏’产量比株施1kg(对照)增产116.9%,且‘国仁杏’的杏仁蛋白质、脂肪含量最高,分别比对照高2.572%、3.349%,也明显高于其他施肥量处理。
6、杏专用肥适宜施肥时期研究结果表明,‘丰仁杏’春秋两次施肥(春1/3、秋2/3)明显高于春施、夏施和秋施处理。‘丰仁杏’春秋两次施肥叶片中的N、P2O5、K2O、Ca、Mg含量、果仁产量、杏仁蛋白质、脂肪含量分别为2.74%、0.435%、1.47%、1.89%、74mg/kg、87.2g、24.4%、53.2%。
学位年度:2010
2012年1月30日星期一
电接触材料可靠性研究
题名:电接触材料可靠性研究
作者:李彤辉
学位授予单位:天津大学
关键词:电接触;;气体腐蚀;;海水腐蚀;;腐蚀膜层;;腐蚀机制
摘要:
电接触是一门应用非常广泛的学科,随着科学技术的发展,对各种仪器设备的要求也就越来越高,电接触材料的可靠性也就越来rare earth magnets越重要。我国是一个污染比较严重的国家,又由于触点大多暴露于环境之中,因此环境污染是造成电接触故障的最主要原因之一。
本实验通过粉末冶金法制备出AgSnO_2、AgWC、AgSnO_2CeO_2三种电接触材料,并对三种材料分别进行SO_2气体腐蚀和模拟海水腐蚀的研究。对各种材料在不同环境下的腐蚀机制和可靠性进行了研究与探讨。
研究发现SO_2腐蚀条件下,AgWC作为触头材料的力学和电学性能俱佳;添加了CeO_2的AgSnO_2材料虽然使材料在导电性能上略有下降,但能显著提高材料的力学性能,抗熔焊性以及灭弧能力,更适合在高温及高负荷条件下使用。在湿度较大的环境下,由于Ag SnO_2CeO_2材料致密度相对较低,表面的水膜容易渗入到基体组织中去,造成更深度的腐蚀,因此耐蚀性较差,不适合使用。
在含SO_2的较高湿度的空气环境中, Ag具有一定的局部腐蚀倾向,蚀点处所形成的的腐蚀产物主要为硫酸盐。SO_2能够将原本在Ag表面生成的的富保护性的Ag_2O膜转化成多孔疏松缺乏保护性的腐蚀产物,这是SO_2对银有强烈破坏作用的主要原因.材料的腐蚀膜厚度随时间的延长逐渐增厚,但由于气体要通过产物膜层扩散到金属表面与金属化合,因此,随膜厚的增加膜层的增长速率在不断降低。
通过电化学测试发现AgWC在NaCl溶液中的耐蚀性最好,添加稀土氧化物CeO_2后AgSnO_2材料抵抗Cl-侵蚀的能力增大http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php,耐蚀性增强。由于受到溶液电导率以及含氧量的限制,三种材料的腐蚀率随着溶液浓度的升高而先增大后减小,在3%左右时达到最大值也就是说材料在海水中的腐蚀与其他浓度的溶液相比较是最为严重的。
学位年度:2010
作者:李彤辉
学位授予单位:天津大学
关键词:电接触;;气体腐蚀;;海水腐蚀;;腐蚀膜层;;腐蚀机制
摘要:
电接触是一门应用非常广泛的学科,随着科学技术的发展,对各种仪器设备的要求也就越来越高,电接触材料的可靠性也就越来rare earth magnets越重要。我国是一个污染比较严重的国家,又由于触点大多暴露于环境之中,因此环境污染是造成电接触故障的最主要原因之一。
本实验通过粉末冶金法制备出AgSnO_2、AgWC、AgSnO_2CeO_2三种电接触材料,并对三种材料分别进行SO_2气体腐蚀和模拟海水腐蚀的研究。对各种材料在不同环境下的腐蚀机制和可靠性进行了研究与探讨。
研究发现SO_2腐蚀条件下,AgWC作为触头材料的力学和电学性能俱佳;添加了CeO_2的AgSnO_2材料虽然使材料在导电性能上略有下降,但能显著提高材料的力学性能,抗熔焊性以及灭弧能力,更适合在高温及高负荷条件下使用。在湿度较大的环境下,由于Ag SnO_2CeO_2材料致密度相对较低,表面的水膜容易渗入到基体组织中去,造成更深度的腐蚀,因此耐蚀性较差,不适合使用。
在含SO_2的较高湿度的空气环境中, Ag具有一定的局部腐蚀倾向,蚀点处所形成的的腐蚀产物主要为硫酸盐。SO_2能够将原本在Ag表面生成的的富保护性的Ag_2O膜转化成多孔疏松缺乏保护性的腐蚀产物,这是SO_2对银有强烈破坏作用的主要原因.材料的腐蚀膜厚度随时间的延长逐渐增厚,但由于气体要通过产物膜层扩散到金属表面与金属化合,因此,随膜厚的增加膜层的增长速率在不断降低。
通过电化学测试发现AgWC在NaCl溶液中的耐蚀性最好,添加稀土氧化物CeO_2后AgSnO_2材料抵抗Cl-侵蚀的能力增大http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php,耐蚀性增强。由于受到溶液电导率以及含氧量的限制,三种材料的腐蚀率随着溶液浓度的升高而先增大后减小,在3%左右时达到最大值也就是说材料在海水中的腐蚀与其他浓度的溶液相比较是最为严重的。
学位年度:2010
双金属氢氧化物层板的调控制备及其电化学电容性质
题名:双金属氢氧化物层板的调控制备及其电化学电容性质
作者:蒋健伟
学位授予单位:南京航空航天大学
关键词:超级电容器;;双金属氢氧化物;;调控;;赝电容;;稳定性
摘要:
超级电容器具有高比功率、高比电容、高循环稳定性、低成本等优点,已广泛应用于航空航天、交通运输、电子通信等领域。双金属氢氧化物(LDHs)具有典型的类水滑石结构,能够提供较高比表面积形成双电层,且层板中过渡金属元素又可提供大量的电化学活性位来产生法拉第电容;其制备简单,成本低廉,故作为超级电Neodymium magnets容器电极材料极具发展潜力。本文以具有特殊层状结构的LDHs作为研究对象,调变其层板组成与结构,由此改善其电容性能与稳定性,具体内容如下:
(1)以甲醇、乙二醇、丙三醇为介质合成了Co-Al LDHs,获得更小更薄的LDHs纳米片。随着醇中羟基数目增加,其片层变小,性能却逐渐提高。乙二醇中制备的样品在1 A g-1电流密度下比容量达到354 F g-1。循环稳定性和其它电化学性能较水相中制备的有很大提高,丙三醇中制备的LDHs经过2000次充放电循环后容量没有衰减。
(2)通过对层板金属离子进行调变,制备了含不同金属离子的LDHs。对三价离子影响的考察发现,In(III)、Cr(III)均能够拓宽有效电位窗口,比Al(III)的具更好的循环稳定性与大电流容量保持率,但比容量不大;而Co-Al LDHs则具有较大的比容量。Ni-Al LDHs仅能在较小的电流密度下实现较大的比容量。
(3)以甘氨酸为模板导向剂,自组装合成了具有分级结构的LDHs,并对层板二价金属离子比例进行调配,得到兼有大孔和介http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php孔的分级孔道结构。合成中甘氨酸的加入能明显提高LDHs的比容量和大电流下容量的保持率。Co/Ni比为3:2的Co0.6Ni0.4-Al LDHs拥有最佳的结构与电化学性能,其在1 A g-1的放电电流下比容量达到了1207 F g-1。
(4)对普通Ni-Al LDHs在制备过程掺杂稀土La,得到具有结构稳定、性能优异的LDHs。其比容量在2000次大电流充放电循环后,仍能在1 A g-1充放电循环中迅速提高到近1000 F g-1,并在随后的近1800次循环中保持较缓慢的衰减速率;而未掺杂的Ni-Al LDHs在大电流充放循环后比容量衰减到了之前的30%。
学位年度:2010
作者:蒋健伟
学位授予单位:南京航空航天大学
关键词:超级电容器;;双金属氢氧化物;;调控;;赝电容;;稳定性
摘要:
超级电容器具有高比功率、高比电容、高循环稳定性、低成本等优点,已广泛应用于航空航天、交通运输、电子通信等领域。双金属氢氧化物(LDHs)具有典型的类水滑石结构,能够提供较高比表面积形成双电层,且层板中过渡金属元素又可提供大量的电化学活性位来产生法拉第电容;其制备简单,成本低廉,故作为超级电Neodymium magnets容器电极材料极具发展潜力。本文以具有特殊层状结构的LDHs作为研究对象,调变其层板组成与结构,由此改善其电容性能与稳定性,具体内容如下:
(1)以甲醇、乙二醇、丙三醇为介质合成了Co-Al LDHs,获得更小更薄的LDHs纳米片。随着醇中羟基数目增加,其片层变小,性能却逐渐提高。乙二醇中制备的样品在1 A g-1电流密度下比容量达到354 F g-1。循环稳定性和其它电化学性能较水相中制备的有很大提高,丙三醇中制备的LDHs经过2000次充放电循环后容量没有衰减。
(2)通过对层板金属离子进行调变,制备了含不同金属离子的LDHs。对三价离子影响的考察发现,In(III)、Cr(III)均能够拓宽有效电位窗口,比Al(III)的具更好的循环稳定性与大电流容量保持率,但比容量不大;而Co-Al LDHs则具有较大的比容量。Ni-Al LDHs仅能在较小的电流密度下实现较大的比容量。
(3)以甘氨酸为模板导向剂,自组装合成了具有分级结构的LDHs,并对层板二价金属离子比例进行调配,得到兼有大孔和介http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php孔的分级孔道结构。合成中甘氨酸的加入能明显提高LDHs的比容量和大电流下容量的保持率。Co/Ni比为3:2的Co0.6Ni0.4-Al LDHs拥有最佳的结构与电化学性能,其在1 A g-1的放电电流下比容量达到了1207 F g-1。
(4)对普通Ni-Al LDHs在制备过程掺杂稀土La,得到具有结构稳定、性能优异的LDHs。其比容量在2000次大电流充放电循环后,仍能在1 A g-1充放电循环中迅速提高到近1000 F g-1,并在随后的近1800次循环中保持较缓慢的衰减速率;而未掺杂的Ni-Al LDHs在大电流充放循环后比容量衰减到了之前的30%。
学位年度:2010
双金属氢氧化物层板的调控制备及其电化学电容性质
题名:双金属氢氧化物层板的调控制备及其电化学电容性质
作者:蒋健伟
学位授予单位:南京航空航天大学
关键词:超级电容器;;双金属氢氧化物;;调控;;赝电容;;稳定性
摘要:
超级电容器具有高比功率、高比电容、高循环稳定性、低成本等优点,已广泛应用于航空航天、交通运输、电子通信等领域。双金属氢氧化物(LDHs)具有典型的类水滑石结构,能够提供较高比表面积形成双电层,且层板中过渡金属元素又可提供大量的电化学活性位来产生法拉第电容;其制备简单,成本低廉,故作为超级电容器rare earth magnets电极材料极具发展潜力。本文以具有特殊层状结构的LDHs作为研究对象,调变其层板组成与结构,由此改善其电容性能与稳定性,具体内容如下:
(1)以甲醇、乙二醇、丙三醇为介质合成了Co-Al LDHs,获得更小更薄的LDHs纳米片。随着醇中羟基数目增加,其片层变小,性能却逐渐提高。乙二醇中制备的样品在1 A g-1电流密度下比容量达到354 F g-1。循环稳定性和其它电化学性能较水相中制备的有很大提高,丙三醇中制备的LDHs经过2000次充放电循环后容量没有衰减。
(2)通过对层板金属离子进行调变,制备了含不同金属离子的LDHs。对三价离子影响的考察发现,In(III)、Cr(III)均能够拓宽有效电位窗口,比Al(III)的具更好的循环稳定性与大电流容量保持率,但比容量不大;而Co-Al LDHs则具有较大的比容量。Ni-Al LDHs仅能在较小的电流密度下实现较大的比容量。
(3)以甘氨酸为模板导向剂,自组装合成了具有分级结构的LDHs,并对层板二价金属离子比例进行调配,得到兼有大孔和介孔的分级孔道结构。合成中甘氨酸的加入能明显提高LDHs的比容量和大电流下容量的保持率。Co/Ni比为3:2的Co0.6Ni0.4-Al LDHs拥有最佳的结构与电化学性能,其在1 A g-1的放电电流下比容量达到了1207 F g-1。
(4)对普通Ni-Al LDHs在制备http://www.chinamagnets.biz/过程掺杂稀土La,得到具有结构稳定、性能优异的LDHs。其比容量在2000次大电流充放电循环后,仍能在1 A g-1充放电循环中迅速提高到近1000 F g-1,并在随后的近1800次循环中保持较缓慢的衰减速率;而未掺杂的Ni-Al LDHs在大电流充放循环后比容量衰减到了之前的30%。
学位年度:2010
作者:蒋健伟
学位授予单位:南京航空航天大学
关键词:超级电容器;;双金属氢氧化物;;调控;;赝电容;;稳定性
摘要:
超级电容器具有高比功率、高比电容、高循环稳定性、低成本等优点,已广泛应用于航空航天、交通运输、电子通信等领域。双金属氢氧化物(LDHs)具有典型的类水滑石结构,能够提供较高比表面积形成双电层,且层板中过渡金属元素又可提供大量的电化学活性位来产生法拉第电容;其制备简单,成本低廉,故作为超级电容器rare earth magnets电极材料极具发展潜力。本文以具有特殊层状结构的LDHs作为研究对象,调变其层板组成与结构,由此改善其电容性能与稳定性,具体内容如下:
(1)以甲醇、乙二醇、丙三醇为介质合成了Co-Al LDHs,获得更小更薄的LDHs纳米片。随着醇中羟基数目增加,其片层变小,性能却逐渐提高。乙二醇中制备的样品在1 A g-1电流密度下比容量达到354 F g-1。循环稳定性和其它电化学性能较水相中制备的有很大提高,丙三醇中制备的LDHs经过2000次充放电循环后容量没有衰减。
(2)通过对层板金属离子进行调变,制备了含不同金属离子的LDHs。对三价离子影响的考察发现,In(III)、Cr(III)均能够拓宽有效电位窗口,比Al(III)的具更好的循环稳定性与大电流容量保持率,但比容量不大;而Co-Al LDHs则具有较大的比容量。Ni-Al LDHs仅能在较小的电流密度下实现较大的比容量。
(3)以甘氨酸为模板导向剂,自组装合成了具有分级结构的LDHs,并对层板二价金属离子比例进行调配,得到兼有大孔和介孔的分级孔道结构。合成中甘氨酸的加入能明显提高LDHs的比容量和大电流下容量的保持率。Co/Ni比为3:2的Co0.6Ni0.4-Al LDHs拥有最佳的结构与电化学性能,其在1 A g-1的放电电流下比容量达到了1207 F g-1。
(4)对普通Ni-Al LDHs在制备http://www.chinamagnets.biz/过程掺杂稀土La,得到具有结构稳定、性能优异的LDHs。其比容量在2000次大电流充放电循环后,仍能在1 A g-1充放电循环中迅速提高到近1000 F g-1,并在随后的近1800次循环中保持较缓慢的衰减速率;而未掺杂的Ni-Al LDHs在大电流充放循环后比容量衰减到了之前的30%。
学位年度:2010
模板法制备层状锰酸锂材料及其掺杂改性研究
题名:模板法制备层状锰酸锂材料及其掺杂改性研究
作者:周振华
学位授予单位:南京航空航天大学
关键词:层状锰酸锂;;模板法;;稀土元素掺杂;;电化学性能;;纳米材料
摘要:
锰酸锂材料由于具有资源丰富、价格低廉、对环境友好、耐过充放电、耐大电流放电和安全性能好等优点,被认为是最有前途的正极材料之一,尤其适合用作未来电动车动力电池的正极材料。在锰氧化物中可用作正极材料的有尖晶石型LiMn_2O_4和层状LiMnO2。但是尖晶石型LiMn_2O_4初始容量较低、循环性能差,而层状LiMn0_2理论容量高达285mAh/g,几乎是LiMn2O4的两倍,循环性能较好,引起来人们极大的Neodymium magnets兴趣,逐渐成为近年来的研究热点,是一种具有广阔发展前景的正极材料。
本文首先以商业级大孔径硅胶为模板,利用硅胶的多孔结构制备了具有纳米尺寸的LiMnO2正极材料,TEM透射电镜显示模板法制备的材料的颗粒尺寸在30—50nm之间,与硅胶孔径尺寸基本吻合。然后采用普通法制备了微米级LiMnO2材料。用循环充放电测试考察了产物的电化学性能,结果显示模板法制备的纳米尺寸LiMnO_2与微米级材料相比显示了更好的充放电性能和循环稳定性,但是两者放电比容量都较低。
为了更好提高材料的放电比容量和循环性能,在模板法的基础上分别掺杂不同的稀土元素Ce和La。XRD物相结果表明所制备的掺杂材料结晶度较好,纯度较高。颗粒尺寸也都在硅胶孔径范围内。充放电测试显示掺杂La或者Ce后,无论是材料的放电比容量和循环性能都有了较大幅度的提高。其中2%Ce掺杂的锰酸锂材料初次容量为108.6mAh/g,在30次循环后容量是98.8 mAh/g,容量保持率在90.9%。4%La掺杂的锰酸锂材料初次容量为113.5mAh/g,循环30次后其放电比容量是103mAh/g,容量保持率为90.7%。
在模板法单元掺杂的基础上尝试二元掺杂,以期能进一步提高材料的电化学性能。我们分别在2%Ce和4%La掺杂的基础上分别掺杂不同比例的Ni,充放电测试表明掺杂后材料的放电比容量都有一个稳步上升的过程,然后趋http://www.chinamagnets.biz/于稳定,其中LiMn_(0.90)Ni_(0.08)Ce_(0.02)O_2首次放电比容量是87.8mAh/g,循环30次后其放电比容量为132.4 mAh/g,容量保持率为150.7%。LiMn_(0.86)Ni_(0.10)La_(0.04)O_2首次放电比容量是106.1mAh/g,循环30次后其放电比容量为141.3mAh/g,容量保持率为133.2%。这也同时说明了掺杂元素在抑制结构相变,提高循环稳定性上发挥了关键作用。
学位年度:2010
作者:周振华
学位授予单位:南京航空航天大学
关键词:层状锰酸锂;;模板法;;稀土元素掺杂;;电化学性能;;纳米材料
摘要:
锰酸锂材料由于具有资源丰富、价格低廉、对环境友好、耐过充放电、耐大电流放电和安全性能好等优点,被认为是最有前途的正极材料之一,尤其适合用作未来电动车动力电池的正极材料。在锰氧化物中可用作正极材料的有尖晶石型LiMn_2O_4和层状LiMnO2。但是尖晶石型LiMn_2O_4初始容量较低、循环性能差,而层状LiMn0_2理论容量高达285mAh/g,几乎是LiMn2O4的两倍,循环性能较好,引起来人们极大的Neodymium magnets兴趣,逐渐成为近年来的研究热点,是一种具有广阔发展前景的正极材料。
本文首先以商业级大孔径硅胶为模板,利用硅胶的多孔结构制备了具有纳米尺寸的LiMnO2正极材料,TEM透射电镜显示模板法制备的材料的颗粒尺寸在30—50nm之间,与硅胶孔径尺寸基本吻合。然后采用普通法制备了微米级LiMnO2材料。用循环充放电测试考察了产物的电化学性能,结果显示模板法制备的纳米尺寸LiMnO_2与微米级材料相比显示了更好的充放电性能和循环稳定性,但是两者放电比容量都较低。
为了更好提高材料的放电比容量和循环性能,在模板法的基础上分别掺杂不同的稀土元素Ce和La。XRD物相结果表明所制备的掺杂材料结晶度较好,纯度较高。颗粒尺寸也都在硅胶孔径范围内。充放电测试显示掺杂La或者Ce后,无论是材料的放电比容量和循环性能都有了较大幅度的提高。其中2%Ce掺杂的锰酸锂材料初次容量为108.6mAh/g,在30次循环后容量是98.8 mAh/g,容量保持率在90.9%。4%La掺杂的锰酸锂材料初次容量为113.5mAh/g,循环30次后其放电比容量是103mAh/g,容量保持率为90.7%。
在模板法单元掺杂的基础上尝试二元掺杂,以期能进一步提高材料的电化学性能。我们分别在2%Ce和4%La掺杂的基础上分别掺杂不同比例的Ni,充放电测试表明掺杂后材料的放电比容量都有一个稳步上升的过程,然后趋http://www.chinamagnets.biz/于稳定,其中LiMn_(0.90)Ni_(0.08)Ce_(0.02)O_2首次放电比容量是87.8mAh/g,循环30次后其放电比容量为132.4 mAh/g,容量保持率为150.7%。LiMn_(0.86)Ni_(0.10)La_(0.04)O_2首次放电比容量是106.1mAh/g,循环30次后其放电比容量为141.3mAh/g,容量保持率为133.2%。这也同时说明了掺杂元素在抑制结构相变,提高循环稳定性上发挥了关键作用。
学位年度:2010
基于滑模变结构的永磁同步电动机矢量控制系统的研究
题名:基于滑模变结构的永磁同步电动机矢量控制系统的研究
作者:朱祥华
学位授予单位:哈尔滨理工大学
关键词:永磁同步电动机;;矢量控制;;滑模变结构组合控制;;空间电压矢量脉宽调制
摘要:
随着电力电子技术、微型计算机技术、稀土永磁材料和控制理论的飞速发展,永磁同步电动机在中小功率的运动控制系统中得到了广泛应用,尤其是在伺服传动领域,永磁同步电动机逐步取代直流电动机、步进电动机成为伺服驱动的发展方向。因此,研究以永磁同步电动机为执行电机、以数字信号处理器为核心器件、采用rare earth magnets矢量控制策略实现全数字式的永磁同步电动机系统具有十分重要的现实意义。
本文首先建立了永磁同步电动机的数学模型,深入研究了永磁同步电动机的矢量控制理论,并在此基础上讨论了永磁同步电动机的控制方案,经比较矢量控制的四种电流控制方法,确定了基于id = 0的矢量控制方案及其电流反馈控制系统结构,并分析了电流解耦的主要影响因素。最后从滑模变结构理论出发,针对永磁同步电动机矢量控制系统,设计了滑模变结构与PI的组合速度环控制器,克服了常规滑模控制器(VSC)在滑模面附近的高频颤动,提高了稳态精度。
随后利用Matlab软件建立了基于滑模变结构的永磁同步电动机矢量控制系统的仿真模型,并在此基础上进行了大量的仿真研究。同时结合实际系统,介绍了以TMS320F2812为控制核心的全数字化永磁同步电机控制系统的硬件和软件设计,对控制系统硬件和软件各部分的结构和功能作了详细阐述。此外,还利用所http://www.chinamagnets.biz/建立的实验平台进行了大量的实验研究。仿真及实验结果均表明本系统具有良好的动静态特性以及较高的精度。可以满足伺服控制的需要。
学位年度:2010
作者:朱祥华
学位授予单位:哈尔滨理工大学
关键词:永磁同步电动机;;矢量控制;;滑模变结构组合控制;;空间电压矢量脉宽调制
摘要:
随着电力电子技术、微型计算机技术、稀土永磁材料和控制理论的飞速发展,永磁同步电动机在中小功率的运动控制系统中得到了广泛应用,尤其是在伺服传动领域,永磁同步电动机逐步取代直流电动机、步进电动机成为伺服驱动的发展方向。因此,研究以永磁同步电动机为执行电机、以数字信号处理器为核心器件、采用rare earth magnets矢量控制策略实现全数字式的永磁同步电动机系统具有十分重要的现实意义。
本文首先建立了永磁同步电动机的数学模型,深入研究了永磁同步电动机的矢量控制理论,并在此基础上讨论了永磁同步电动机的控制方案,经比较矢量控制的四种电流控制方法,确定了基于id = 0的矢量控制方案及其电流反馈控制系统结构,并分析了电流解耦的主要影响因素。最后从滑模变结构理论出发,针对永磁同步电动机矢量控制系统,设计了滑模变结构与PI的组合速度环控制器,克服了常规滑模控制器(VSC)在滑模面附近的高频颤动,提高了稳态精度。
随后利用Matlab软件建立了基于滑模变结构的永磁同步电动机矢量控制系统的仿真模型,并在此基础上进行了大量的仿真研究。同时结合实际系统,介绍了以TMS320F2812为控制核心的全数字化永磁同步电机控制系统的硬件和软件设计,对控制系统硬件和软件各部分的结构和功能作了详细阐述。此外,还利用所http://www.chinamagnets.biz/建立的实验平台进行了大量的实验研究。仿真及实验结果均表明本系统具有良好的动静态特性以及较高的精度。可以满足伺服控制的需要。
学位年度:2010
2012年1月29日星期日
铜铝异种有色金属钎焊的性能试验研究
题名:铜铝异种有色金属钎焊的性能试验研究
作者:闫飞
学位授予单位:合肥工业大学
关键词:铜铝;;钎焊;;接头性能;;焊接缺陷
摘要:
本文概述了铜、铝合金的性能特点及其在工业领域中的应用前景,分析了铜铝异种金属焊接过程中的主要问题,阐述了能够应用于铜、铝合金焊接的各种焊接方法、工艺要素及相关研究现状,其中包括冷压焊、摩擦焊、扩散焊、爆Neodymium Magnets炸焊、电阻焊、激光焊、钎焊等,提出了有待进一步研究的相关问题。
本课题以铜铝异种金属构件潜在的工程应用为背景,试验选用钎焊方法将两者连接起来,并就相关的钎焊问题开展试验研究,内容包括对铜铝异种金属进行真空钎焊和火焰钎焊试验;选用Al-Si-Mg钎料去研究不同的工艺参数对真空钎焊接头性能的影响,并选用不同的钎料去研究钎料成分对火焰钎焊接头性能的影响;选用利用金相显微镜、显微硬度计、万能拉伸试验机、扫描电子显微镜、X射线衍射仪等试验测试手段,对焊接接头的微观组织结构、显微硬度、接头力学性能、接头区形貌特征及物相成份等进行分析;探讨铜铝及其合金焊接过程中产生宏观缺陷和微观缺陷的原因和预防措施。
研究结果表明:在工艺参数选择合适的情况下,钎焊可以得到表面成形良好的接头。钎焊温度,保温时间和钎料层厚度是影响真空钎焊接头质量的主要因素,而钎料成分和装配间隙是影响火焰钎焊接头质量的主要因素。火焰钎焊接头的钎缝中心区硬度明显高于两侧扩散区的硬度,进一步验证钎缝中有大量脆性相的生成。真空钎焊和扩散焊接头的强度相对偏低,而火焰钎焊的接头强度相对较高。接头拉伸断裂多发生在钎焊中心区,而且断裂面上有撕裂的痕迹,小部分呈现光亮带,可以推断断裂的方式http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets可能是韧脆混合断裂形貌。钎缝中的物相主要有α-Al固溶体,CuAl2,Al4Cu9等脆性相,脆性相的存在会严重削弱接头的强度,并导致焊缝中产生微裂纹。接头中常见的缺陷有脆性相、气孔、裂纹等。钎料中加入少量的稀土元素不仅可以细化钎缝中晶粒,而且可以弥散分布焊缝中的脆性相。焊前彻底清除焊件表面的氧化膜和油垢,加强对焊缝的保护等工艺措施,可以有效地减少焊缝中气孔和裂纹。
学位年度:2010
作者:闫飞
学位授予单位:合肥工业大学
关键词:铜铝;;钎焊;;接头性能;;焊接缺陷
摘要:
本文概述了铜、铝合金的性能特点及其在工业领域中的应用前景,分析了铜铝异种金属焊接过程中的主要问题,阐述了能够应用于铜、铝合金焊接的各种焊接方法、工艺要素及相关研究现状,其中包括冷压焊、摩擦焊、扩散焊、爆Neodymium Magnets炸焊、电阻焊、激光焊、钎焊等,提出了有待进一步研究的相关问题。
本课题以铜铝异种金属构件潜在的工程应用为背景,试验选用钎焊方法将两者连接起来,并就相关的钎焊问题开展试验研究,内容包括对铜铝异种金属进行真空钎焊和火焰钎焊试验;选用Al-Si-Mg钎料去研究不同的工艺参数对真空钎焊接头性能的影响,并选用不同的钎料去研究钎料成分对火焰钎焊接头性能的影响;选用利用金相显微镜、显微硬度计、万能拉伸试验机、扫描电子显微镜、X射线衍射仪等试验测试手段,对焊接接头的微观组织结构、显微硬度、接头力学性能、接头区形貌特征及物相成份等进行分析;探讨铜铝及其合金焊接过程中产生宏观缺陷和微观缺陷的原因和预防措施。
研究结果表明:在工艺参数选择合适的情况下,钎焊可以得到表面成形良好的接头。钎焊温度,保温时间和钎料层厚度是影响真空钎焊接头质量的主要因素,而钎料成分和装配间隙是影响火焰钎焊接头质量的主要因素。火焰钎焊接头的钎缝中心区硬度明显高于两侧扩散区的硬度,进一步验证钎缝中有大量脆性相的生成。真空钎焊和扩散焊接头的强度相对偏低,而火焰钎焊的接头强度相对较高。接头拉伸断裂多发生在钎焊中心区,而且断裂面上有撕裂的痕迹,小部分呈现光亮带,可以推断断裂的方式http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets可能是韧脆混合断裂形貌。钎缝中的物相主要有α-Al固溶体,CuAl2,Al4Cu9等脆性相,脆性相的存在会严重削弱接头的强度,并导致焊缝中产生微裂纹。接头中常见的缺陷有脆性相、气孔、裂纹等。钎料中加入少量的稀土元素不仅可以细化钎缝中晶粒,而且可以弥散分布焊缝中的脆性相。焊前彻底清除焊件表面的氧化膜和油垢,加强对焊缝的保护等工艺措施,可以有效地减少焊缝中气孔和裂纹。
学位年度:2010
Mg-Zn-RE-Zr合金的组织与性能研究
题名:Mg-Zn-RE-Zr合金的组织与性能研究
作者:张大华
学位授予单位:兰州理工大学
关键词:ZW21镁合金;;合金元素;;热处理;;组织;;力学性能
摘要:
镁合金是目前工业应用最轻质的金属材料,具有巨大的发展潜力,日益受到材料工作者的广泛青睐。成为继钢铁、铝之后第三大金属工程材料,被誉为“21世纪绿色工程材料”。然而普通镁合金的强度不高,传统的高强高韧镁合金一Neodymium Magnets般含有较高的稀土元素,这大大提高了其生产成本。因此,研究与开发低成本的高强高韧镁合金显得十分必要。本文以ZW21合金(2.0%Zn,1.0%Y,0.5%Nd,0.5%Sn,0.3%Zr和0.05%Ca)为基础,研究Zn、Y、Nd、Sn、Zr与Ca等合金元素对其组织及力学性能的影响,同时研究了热处理工艺对ZW21合金的组织及力学性能的影响。结果表明：
在ZW21合金中,各添加元素对合金的组织有着重要的影响。其中Zn、Y、Nd不同的加入量会使合金中组织形貌和相成分发生变化。Mg、Zn、RE(Y或者Nd)元素之间会形成三元二次相,合金中Zn/RE的值决定了组织中二次相的组成：当Zn/RE小于0.60时,二次相为H相；当Zn/RE为0.60～0.85时,二次相为H相+W相；当Zn/RE为0.85～2.05时,二次相为W相；当Zn/RE为2.05～5.00时,二次相为W相+I相。
ZW21合金铸态的抗拉强度为207MPa,伸长率为16.9%,硬度为52.8HV。ZW21合金铸态组织由α-Mg相和W相组成,在525℃固溶http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets
处理4小时后水淬,变为单一的α-Mg相,然后在250℃时效处理过程中析出W相。时效处理(250℃×24h)使ZW21合金的力学性能得到提高。其中抗拉强度、伸长率和硬度分别增加到243MPa、20.8%和58.7HV,与铸态相比,时效态合金的抗拉强度提高了17.4%,伸长率提高了23.1%,硬度提高了11.2%。
学位年度:2010
作者:张大华
学位授予单位:兰州理工大学
关键词:ZW21镁合金;;合金元素;;热处理;;组织;;力学性能
摘要:
镁合金是目前工业应用最轻质的金属材料,具有巨大的发展潜力,日益受到材料工作者的广泛青睐。成为继钢铁、铝之后第三大金属工程材料,被誉为“21世纪绿色工程材料”。然而普通镁合金的强度不高,传统的高强高韧镁合金一Neodymium Magnets般含有较高的稀土元素,这大大提高了其生产成本。因此,研究与开发低成本的高强高韧镁合金显得十分必要。本文以ZW21合金(2.0%Zn,1.0%Y,0.5%Nd,0.5%Sn,0.3%Zr和0.05%Ca)为基础,研究Zn、Y、Nd、Sn、Zr与Ca等合金元素对其组织及力学性能的影响,同时研究了热处理工艺对ZW21合金的组织及力学性能的影响。结果表明：
在ZW21合金中,各添加元素对合金的组织有着重要的影响。其中Zn、Y、Nd不同的加入量会使合金中组织形貌和相成分发生变化。Mg、Zn、RE(Y或者Nd)元素之间会形成三元二次相,合金中Zn/RE的值决定了组织中二次相的组成：当Zn/RE小于0.60时,二次相为H相；当Zn/RE为0.60～0.85时,二次相为H相+W相；当Zn/RE为0.85～2.05时,二次相为W相；当Zn/RE为2.05～5.00时,二次相为W相+I相。
ZW21合金铸态的抗拉强度为207MPa,伸长率为16.9%,硬度为52.8HV。ZW21合金铸态组织由α-Mg相和W相组成,在525℃固溶http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets
处理4小时后水淬,变为单一的α-Mg相,然后在250℃时效处理过程中析出W相。时效处理(250℃×24h)使ZW21合金的力学性能得到提高。其中抗拉强度、伸长率和硬度分别增加到243MPa、20.8%和58.7HV,与铸态相比,时效态合金的抗拉强度提高了17.4%,伸长率提高了23.1%,硬度提高了11.2%。
学位年度:2010
（La，R）（Fe，Co，Si）_（13）系列化合物的磁性和磁热效应
题名:（La，R）（Fe，Co，Si）_（13）系列化合物的磁性和磁热效应
作者:伊博乐
学位授予单位:内蒙古师范大学
关键词:磁制冷;;磁热效应;;磁相变;;磁熵变
摘要:
磁致冷作为一项高新绿色制冷技术,有望替代传统的蒸汽压缩制冷。NaZn_(13)型立方结构的La(Fe,Si)_(13)系列化合物及其衍生化合物由于具有大磁热效应,且价格低廉、环境友好,有望成为优良磁制冷材料。本文用X射线衍射、扫描电镜和磁性测量系统地研究了(La,R)(Fe,Co,Si)_(13)系列化合物的物相结构、磁性及其磁热效应。
本论文的主要研究结果如下:(1)XRD分析得出La_(1.1-x)Gd_xFe_(11.4)Si_(1.6) ( x=0, 0.05, 0.1, 0.15和0.2)系列化合物均由NaZn_(13)型立方结构(空间群Fm-3c)组成。居里温度随着Gd的增加分别从195 K (x=0)升高到198 K (x=0.2)。Gd替代La弱化了其居里温度附近的场致变磁转变,继而从一级相变转变为二级相变。化合物的热滞随Neodymium Magnets着Gd的增加有所减小。La_(1.1-x)Gd_xFe_(11.4)Si_(1.6)(x=0, 0.05, 0.1, 0.15和0.2)系列化合物在磁场变化为0 ~ 1.5 T下的最大磁熵变从14.1 Jkg~(-1)K~(-1)降到9.6 Jkg~(-1)K~(-1)。(2)为了调节居里温度,对LaGd_(0.1)Fe_(11.4)Si_(1.6) (x=0.1, 0.3, 0.5, 0.7和0.9)和La0.9Ce0.2Fe11.0Si2.0 (x=0, 0.2, 0.4和0.8)系列化合物添加了Co元素。由LaGd0.1Fe11.1Co0.3Si1.6化合物的扫描电镜照片分析得出,化合物主要由三相组成,分别为主相LaGd0.17Fe11.16Co0.43Si1.68 (灰色区域),小部份富铁相LaGd0.68Fe116.9Co3.77Si4.57(黑色区域)和富镧相LaGd0.12Fe0.96Co0.14Si1.06(白色区域)。用Co替代Fe以后使LaGd0.1Fe11.4-xCoxSi1.6和La0.9Ce0.2Fe11-xCoxSi2.0系列化合物的居里温度调到了室温附近。磁性测量表明,该系列化合物不存在热滞。磁场变化为0 ~ 1.5 T下,LaGd_(0.1)Fe_(11.4)Si_(1.6) (x=0.1, 0.3, 0.5, 0.7和0.9)和La0.9Ce0.2Fe11.0Si2.0 (x=0, 0.2, 0.4和0.8)系列化合物的最大磁熵变分别从13.8 Jkg~(-1)K~(-1)降到1.5 Jkg~(-1)K~(-1)以及从5.6 Jkg~(-1)K~(-1)降到2.7 Jkg~(-1)K~(-1)。等温磁熵变随Co含量的增加而减小。(3)研究了适当添加稀土元素Ce、Gd、Dy、Er对化合物LaR_(0.1)Fe_(11.4)Si_(1.6)的居里温度和磁热效应的影响。添加R=La、Ce、Gd、Dy和Er后该系列化合物http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets的居里温度分别为196, 190, 196, 191和194 K。其中添加Ce的化合物的磁熵变为最大,添加Er的化合物的磁熵变为最小。虽然如此,由于等温磁熵曲线的宽度,Ce替代化合物的相对制冷能力与其他化合物的相当。
学位年度:2010
作者:伊博乐
学位授予单位:内蒙古师范大学
关键词:磁制冷;;磁热效应;;磁相变;;磁熵变
摘要:
磁致冷作为一项高新绿色制冷技术,有望替代传统的蒸汽压缩制冷。NaZn_(13)型立方结构的La(Fe,Si)_(13)系列化合物及其衍生化合物由于具有大磁热效应,且价格低廉、环境友好,有望成为优良磁制冷材料。本文用X射线衍射、扫描电镜和磁性测量系统地研究了(La,R)(Fe,Co,Si)_(13)系列化合物的物相结构、磁性及其磁热效应。
本论文的主要研究结果如下:(1)XRD分析得出La_(1.1-x)Gd_xFe_(11.4)Si_(1.6) ( x=0, 0.05, 0.1, 0.15和0.2)系列化合物均由NaZn_(13)型立方结构(空间群Fm-3c)组成。居里温度随着Gd的增加分别从195 K (x=0)升高到198 K (x=0.2)。Gd替代La弱化了其居里温度附近的场致变磁转变,继而从一级相变转变为二级相变。化合物的热滞随Neodymium Magnets着Gd的增加有所减小。La_(1.1-x)Gd_xFe_(11.4)Si_(1.6)(x=0, 0.05, 0.1, 0.15和0.2)系列化合物在磁场变化为0 ~ 1.5 T下的最大磁熵变从14.1 Jkg~(-1)K~(-1)降到9.6 Jkg~(-1)K~(-1)。(2)为了调节居里温度,对LaGd_(0.1)Fe_(11.4)Si_(1.6) (x=0.1, 0.3, 0.5, 0.7和0.9)和La0.9Ce0.2Fe11.0Si2.0 (x=0, 0.2, 0.4和0.8)系列化合物添加了Co元素。由LaGd0.1Fe11.1Co0.3Si1.6化合物的扫描电镜照片分析得出,化合物主要由三相组成,分别为主相LaGd0.17Fe11.16Co0.43Si1.68 (灰色区域),小部份富铁相LaGd0.68Fe116.9Co3.77Si4.57(黑色区域)和富镧相LaGd0.12Fe0.96Co0.14Si1.06(白色区域)。用Co替代Fe以后使LaGd0.1Fe11.4-xCoxSi1.6和La0.9Ce0.2Fe11-xCoxSi2.0系列化合物的居里温度调到了室温附近。磁性测量表明,该系列化合物不存在热滞。磁场变化为0 ~ 1.5 T下,LaGd_(0.1)Fe_(11.4)Si_(1.6) (x=0.1, 0.3, 0.5, 0.7和0.9)和La0.9Ce0.2Fe11.0Si2.0 (x=0, 0.2, 0.4和0.8)系列化合物的最大磁熵变分别从13.8 Jkg~(-1)K~(-1)降到1.5 Jkg~(-1)K~(-1)以及从5.6 Jkg~(-1)K~(-1)降到2.7 Jkg~(-1)K~(-1)。等温磁熵变随Co含量的增加而减小。(3)研究了适当添加稀土元素Ce、Gd、Dy、Er对化合物LaR_(0.1)Fe_(11.4)Si_(1.6)的居里温度和磁热效应的影响。添加R=La、Ce、Gd、Dy和Er后该系列化合物http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets的居里温度分别为196, 190, 196, 191和194 K。其中添加Ce的化合物的磁熵变为最大,添加Er的化合物的磁熵变为最小。虽然如此,由于等温磁熵曲线的宽度,Ce替代化合物的相对制冷能力与其他化合物的相当。
学位年度:2010
冀北赤城花岗岩的岩石学、地球化学与锆石SHRIMP年代学
题名:冀北赤城花岗岩的岩石学、地球化学与锆石SHRIMP年代学
作者:刘胤
学位授予单位:成都理工大学
关键词:花岗岩;;岩石地球化学;;锆石SHRIMP U-Pb年龄;;赤城;;冀北
摘要:
冀北赤城花岗岩主要出露于赤城县城以北的马营、云州水库、独石口和镇宁堡等地,包括马营的红墩梁、云洲水库的舍身崖、独石口的冰山梁和镇宁堡的东沟楼等四个岩体。这些花岗岩体均呈岩珠状产出,为中深成至深成侵入岩,它们主要侵位于晚古生代―红旗营子群‖的黑云斜长片麻岩之中,局部侵位于样墩片麻岩,部分岩体则为侏罗系火山岩所覆盖而呈沉积接触关系。其中,红墩梁、舍身崖和东沟楼等岩体的出Neodymium Magnets露面积大小不等,为黑云二长花岗岩,具典型的花岗结构和块状构造,主要矿物成分有斜长石、钾长石、石英,次要矿物为黑云母。黑云二长花岗岩的地球化学特征显示其具较高的SiO_2含量(73.93 %～76.44 %)以及相对较低的Al__2O_3(11.56 %—12.95 %)、Na_2O (3.88 %—4.38 %)和K_2O含量(4.37 %—5.06 %),ΣREE相对较低(92.51 ppm—240.53 ppm),(La/Yb)N介于6.66与18.27之间,具明显的负Eu异常(δEu=0.15—0.38),Ce异常不明显。其fSm/Nd和εNd(t)分别为-0.31—-0.53和-13.25—-15.80,为起源于陆壳环境的钙碱性系列花岗岩类。冰山梁岩体的矿物成分有斜长石(40 %—45 %)、钾长石(30 %—35 %)、石英(10 %—15 %)和少量黑云母,在地球化学特征上,具有较低的SiO_2含量(66.31 %)以及相对较高的Al_2O_3(15.13 %)、Na_2O(4.40 %)和K_2O含量(5.51 %),ΣREE相对较高(373.95 ppm),(La/Yb)N为30.77,具不太明显的负Eu异常(δEu=0.78),Ce异常相对较明显(δCe=0.70)。其fSm/Nd和εNd(t)分别为-0.50和-12.18,为起源于陆壳环境的花岗闪长岩类。对于二长花岗岩类,马营的红墩梁岩体中的锆石具有明显的岩浆成因环带,Th/U比值为0.50～1.45,锆石SHRIMP U-Pb同位素数据表明其~(206)Pb/~(238)U平均年龄为143.9±2.2 Ma;东沟楼黑云二长花岗岩体中的锆石具有明显的岩浆成因环带,Th/U比值为0.61～0.96,锆石颗粒的SHRIMP U-Pb同位素分析数据表明其~(206)Pb/~(238)U平均年龄为138.0±2.2 Ma;云州水库的舍身崖岩体,Th/U比值为2.19,数据显示该岩体的年龄在136.0±3.3Ma左右。对于花岗闪长岩类,冰山梁岩体中的锆石也具明显的岩浆成因环带,Th/U比值较高,为1.18～2.73,锆石SHRIMP U-Pb同位素测年分析数据表明其~(206)Pb/~(238)U平均年龄为228.0±3.1 Ma。
根据获得的锆石SHRIMP年龄资料来看,以冰山粱岩体为代表的花岗闪长岩体的锆石SHRIMP U-Pb年龄为228 Ma,形成于印支期,而红墩粱、舍身崖和东沟楼等黑云二长花岗岩体的锆石SHRIMP年龄介于136Ma与144 Ma之间,平均值为143 Ma,明显形成于燕山期,这与前人认为该地区花岗岩体是海西期明显不同。
冀北赤城地区两期花岗岩体的存在,一方面暗示该地区先后经历了印支期和燕山期两次岩浆热事件,这对该地区的岩石—构造单元的大地构造属性等相关研究提供了岩石学和年代学的依据;一方面限定了冀北红旗营子群整http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets体推覆的最晚时间应该是在228Ma之前;另一方面结合华北克拉通中生代遭受的破坏,赤城地区花岗岩的存在和年代学的研究,结合对赤城花岗岩Sm-Nd同位素的研究,不仅说明了在中生代华北克拉通北缘中段地区的岩石圈减薄作用,还为华北克拉通中生代的破坏的具体时间提供了岩石学证据,从而限定了华北克拉通的破坏始于印支期,而在燕山期达到了高潮。
学位年度:2010
作者:刘胤
学位授予单位:成都理工大学
关键词:花岗岩;;岩石地球化学;;锆石SHRIMP U-Pb年龄;;赤城;;冀北
摘要:
冀北赤城花岗岩主要出露于赤城县城以北的马营、云州水库、独石口和镇宁堡等地,包括马营的红墩梁、云洲水库的舍身崖、独石口的冰山梁和镇宁堡的东沟楼等四个岩体。这些花岗岩体均呈岩珠状产出,为中深成至深成侵入岩,它们主要侵位于晚古生代―红旗营子群‖的黑云斜长片麻岩之中,局部侵位于样墩片麻岩,部分岩体则为侏罗系火山岩所覆盖而呈沉积接触关系。其中,红墩梁、舍身崖和东沟楼等岩体的出Neodymium Magnets露面积大小不等,为黑云二长花岗岩,具典型的花岗结构和块状构造,主要矿物成分有斜长石、钾长石、石英,次要矿物为黑云母。黑云二长花岗岩的地球化学特征显示其具较高的SiO_2含量(73.93 %～76.44 %)以及相对较低的Al__2O_3(11.56 %—12.95 %)、Na_2O (3.88 %—4.38 %)和K_2O含量(4.37 %—5.06 %),ΣREE相对较低(92.51 ppm—240.53 ppm),(La/Yb)N介于6.66与18.27之间,具明显的负Eu异常(δEu=0.15—0.38),Ce异常不明显。其fSm/Nd和εNd(t)分别为-0.31—-0.53和-13.25—-15.80,为起源于陆壳环境的钙碱性系列花岗岩类。冰山梁岩体的矿物成分有斜长石(40 %—45 %)、钾长石(30 %—35 %)、石英(10 %—15 %)和少量黑云母,在地球化学特征上,具有较低的SiO_2含量(66.31 %)以及相对较高的Al_2O_3(15.13 %)、Na_2O(4.40 %)和K_2O含量(5.51 %),ΣREE相对较高(373.95 ppm),(La/Yb)N为30.77,具不太明显的负Eu异常(δEu=0.78),Ce异常相对较明显(δCe=0.70)。其fSm/Nd和εNd(t)分别为-0.50和-12.18,为起源于陆壳环境的花岗闪长岩类。对于二长花岗岩类,马营的红墩梁岩体中的锆石具有明显的岩浆成因环带,Th/U比值为0.50～1.45,锆石SHRIMP U-Pb同位素数据表明其~(206)Pb/~(238)U平均年龄为143.9±2.2 Ma;东沟楼黑云二长花岗岩体中的锆石具有明显的岩浆成因环带,Th/U比值为0.61～0.96,锆石颗粒的SHRIMP U-Pb同位素分析数据表明其~(206)Pb/~(238)U平均年龄为138.0±2.2 Ma;云州水库的舍身崖岩体,Th/U比值为2.19,数据显示该岩体的年龄在136.0±3.3Ma左右。对于花岗闪长岩类,冰山梁岩体中的锆石也具明显的岩浆成因环带,Th/U比值较高,为1.18～2.73,锆石SHRIMP U-Pb同位素测年分析数据表明其~(206)Pb/~(238)U平均年龄为228.0±3.1 Ma。
根据获得的锆石SHRIMP年龄资料来看,以冰山粱岩体为代表的花岗闪长岩体的锆石SHRIMP U-Pb年龄为228 Ma,形成于印支期,而红墩粱、舍身崖和东沟楼等黑云二长花岗岩体的锆石SHRIMP年龄介于136Ma与144 Ma之间,平均值为143 Ma,明显形成于燕山期,这与前人认为该地区花岗岩体是海西期明显不同。
冀北赤城地区两期花岗岩体的存在,一方面暗示该地区先后经历了印支期和燕山期两次岩浆热事件,这对该地区的岩石—构造单元的大地构造属性等相关研究提供了岩石学和年代学的依据;一方面限定了冀北红旗营子群整http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets体推覆的最晚时间应该是在228Ma之前;另一方面结合华北克拉通中生代遭受的破坏,赤城地区花岗岩的存在和年代学的研究,结合对赤城花岗岩Sm-Nd同位素的研究,不仅说明了在中生代华北克拉通北缘中段地区的岩石圈减薄作用,还为华北克拉通中生代的破坏的具体时间提供了岩石学证据,从而限定了华北克拉通的破坏始于印支期,而在燕山期达到了高潮。
学位年度:2010
亚硒酸钠联合高压氧对颅脑损伤模型鼠细胞凋亡与病理形态的影响
题名:亚硒酸钠联合高压氧对颅脑损伤模型鼠细胞凋亡与病理形态的影响
作者:马懿
学位授予单位:遵义医学院
关键词:亚硒酸钠;;高压氧;;颅脑损伤;;细胞凋亡;;病理形态学
摘要:
目的：观察亚硒酸钠结合高压氧对颅脑损伤模型鼠的脑组织病理形态学与神经细胞凋亡的影响,分析急性脑创伤的病理和病理生理变化,初步探讨其作用机制,并为稀土元素硒在颅脑损伤方面的治疗提供一定的理论依据。方法：40只SD大鼠随机分为对照组、脑损伤组和治疗组,治疗组又分为(亚硒酸钠组、高压氧组、亚硒酸钠联合高压氧处理组)。亚硒酸钠提前一月进行喂养,然后应用Feeney改良自由落体颅脑损伤装Neodymium Magnets置,参照中度损伤模型的相应指标,建立大鼠闭合性颅脑损伤模型,最后以NSS再将损伤程度统一为中度颅脑损伤程度。涉及高压氧的组别伤后1h、24h、48h做高压氧治疗,各组均以72小时统一留取标本,分别测定脑组织含水量；石蜡切片HE染色光镜下观察大脑皮层以海马CA1区形态变化；TUNEL法检测各组大鼠大脑皮质凋亡细胞表达；免疫组化法检测各组大鼠大脑皮质与海马CA1区caspase-3细胞数的表达；电镜下观察各组大鼠大脑皮质与海马CA1区超微结果变化。数据采用SPSS13.0软件处理,统计处理组间比较采用。One-wayANOVA,相关性分析采用Spearman法。P<0.05为差异有显著性。结果：①脑含水量测定显示：脑损伤组和对照组大鼠比较,脑含水量明显增加(P<0.01)；治疗组与脑损伤组大鼠比较,脑含水量有不同程度的下降(P<0.05),其中联合处理组的下降幅度最多。②光镜下显示：脑损伤组和对照组比较,皮质与海马区胶质细胞显著增多；治疗组和脑损伤组比较,胶质细胞均有不同程度的减少,联合处理组减少最为明显。③细胞凋亡测定：空白组仅有极少数神经细胞呈TUNEL阳性。脑损伤组和对照组比较,皮质凋亡神经细胞数显著增多(P<0.01)；治疗组和脑损伤组比较,均有不同程度的减少(P<0.05),联合处理组减少最为明显(P<0.01)。④Caspase-3阳性细胞表达：空白组仅有极少数Caspase-3阳性细胞表达。脑损伤组和对照组比较,皮质和海马区阳性细胞http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets数显著增多(P<0.01)；治疗组和脑损伤组比较,均有不同程度的减少(P<0.05),联合处理组减少最为明显(P<0.01)。⑤电镜超微结构变化显示：脑损伤组和对照组比较,皮质与海马区细胞结构破坏严重；治疗组和脑损伤组比较,程度减轻,联合处理组最为明显。结论：①亚硒酸钠与高压氧处理均能不同程度的抑制颅脑损伤后引起的神经细胞凋亡。②联合处理组的效果优于两种单一的处理组,说明两种处理方法有协同治疗作用。③亚硒酸钠在颅脑损伤后的病理改变中有一定的保护性作用。
学位年度:2010
作者:马懿
学位授予单位:遵义医学院
关键词:亚硒酸钠;;高压氧;;颅脑损伤;;细胞凋亡;;病理形态学
摘要:
目的：观察亚硒酸钠结合高压氧对颅脑损伤模型鼠的脑组织病理形态学与神经细胞凋亡的影响,分析急性脑创伤的病理和病理生理变化,初步探讨其作用机制,并为稀土元素硒在颅脑损伤方面的治疗提供一定的理论依据。方法：40只SD大鼠随机分为对照组、脑损伤组和治疗组,治疗组又分为(亚硒酸钠组、高压氧组、亚硒酸钠联合高压氧处理组)。亚硒酸钠提前一月进行喂养,然后应用Feeney改良自由落体颅脑损伤装Neodymium Magnets置,参照中度损伤模型的相应指标,建立大鼠闭合性颅脑损伤模型,最后以NSS再将损伤程度统一为中度颅脑损伤程度。涉及高压氧的组别伤后1h、24h、48h做高压氧治疗,各组均以72小时统一留取标本,分别测定脑组织含水量；石蜡切片HE染色光镜下观察大脑皮层以海马CA1区形态变化；TUNEL法检测各组大鼠大脑皮质凋亡细胞表达；免疫组化法检测各组大鼠大脑皮质与海马CA1区caspase-3细胞数的表达；电镜下观察各组大鼠大脑皮质与海马CA1区超微结果变化。数据采用SPSS13.0软件处理,统计处理组间比较采用。One-wayANOVA,相关性分析采用Spearman法。P<0.05为差异有显著性。结果：①脑含水量测定显示：脑损伤组和对照组大鼠比较,脑含水量明显增加(P<0.01)；治疗组与脑损伤组大鼠比较,脑含水量有不同程度的下降(P<0.05),其中联合处理组的下降幅度最多。②光镜下显示：脑损伤组和对照组比较,皮质与海马区胶质细胞显著增多；治疗组和脑损伤组比较,胶质细胞均有不同程度的减少,联合处理组减少最为明显。③细胞凋亡测定：空白组仅有极少数神经细胞呈TUNEL阳性。脑损伤组和对照组比较,皮质凋亡神经细胞数显著增多(P<0.01)；治疗组和脑损伤组比较,均有不同程度的减少(P<0.05),联合处理组减少最为明显(P<0.01)。④Caspase-3阳性细胞表达：空白组仅有极少数Caspase-3阳性细胞表达。脑损伤组和对照组比较,皮质和海马区阳性细胞http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets数显著增多(P<0.01)；治疗组和脑损伤组比较,均有不同程度的减少(P<0.05),联合处理组减少最为明显(P<0.01)。⑤电镜超微结构变化显示：脑损伤组和对照组比较,皮质与海马区细胞结构破坏严重；治疗组和脑损伤组比较,程度减轻,联合处理组最为明显。结论：①亚硒酸钠与高压氧处理均能不同程度的抑制颅脑损伤后引起的神经细胞凋亡。②联合处理组的效果优于两种单一的处理组,说明两种处理方法有协同治疗作用。③亚硒酸钠在颅脑损伤后的病理改变中有一定的保护性作用。
学位年度:2010
层状钙钛矿型Bi_4Ti_3O_（12）铁电薄膜的择优取向生长与回线动力学标度
题名:层状钙钛矿型Bi_4Ti_3O_（12）铁电薄膜的择优取向生长与回线动力学标度
作者:李超
学位授予单位:青岛大学
关键词:Bi_4Ti_3O_(12);;薄膜;;原位外电场诱导;;取向生长;;铁电体;;回线动力学标度
摘要:
层状钙钛矿型铁电体Bi4Ti3O12的居里温度高,自发极化大，Ps靠近α轴。稀土掺杂的Bi4Ti3Oi2薄膜在金属电极上耐疲劳,是实现铁电存储器应用的最佳材料之一。人们希望能制备沿α轴(或近α轴)均匀取向生长(取向度超过95%)的Bi4Ti3Oi2基铁电薄膜,以便获得大的剩余极化。同时,为满足铁电存储器实用要求,很有必Neodymium Magnets要直接在金属电极上取向生长铁电薄膜。但是实验证明,要求钙钛矿型铁电薄膜在金属电极上均匀取向生长相当困难。
本论文在Bi4Ti3O12薄膜快速升温晶化时,通过原位外加电场诱导薄膜中晶粒取向成核,用sol-gel工艺直接在标准型(111)Pt/Ti/SiO2/Si(100)衬底上制备了高a/b轴择优取向的Bi4Ti3O12薄膜。较系统研究了外电场大小、升温速率及退火温度对Bi4Ti3O12薄膜择优取向生长的影响。结果表明,若铁电薄膜的居里温度高于其结晶温度,在薄膜晶化成核时,外电场的确可以有效地诱导晶粒取向成核,晶粒的自发极化倾向与外电场方向一致。在外电场2 kV,升温速率60℃/s,退火温度750℃时获得高a/b轴择优取向的Bi4Ti3O12薄膜,该薄膜电滞回线饱和,剩余极化2Pr值高达63μC·cm-2,由此估计其中沿a/b轴择优取向晶粒的体积分数约为62%。
对比研究了a/b轴择优取向和随机取向Bi4Ti3O12铁电薄膜的回线动力学标度。结果表明,a/b轴择优取向Bi4Ti3O12薄膜的回线面积<A>随外加电场的频率f和幅值E0的变化关系为：在低频段(外电场频率f＜1/τe时),标度关系为<A>∝f0.018E00.6；在高频段(外场频率f＞1/τe时),有标度关系<A>∝f-0.026E00.6。而随机取向Bi4Ti3O12薄膜的<A>随外加电场的变化关系在高频段和低频段可统一为<A>∝f-0.106E01.667。实验发现,a/b轴择优取向Bi4Ti3O12铁电薄膜的特征翻转时间τe随外电场幅值的增大而减小,回线饱和时其畴翻转特征时间为1.1 ms,而随机取向的薄膜中,在测试频率范围内无畴翻转的特征时间出现。两种不同取向薄膜标度关系的差异反映了a/b轴择优与随机取向薄膜中铁http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets电畴翻转的差异。与a/b轴择优取向Bi4Ti3O12薄膜相比,随机取向薄膜的回线面积<A>随频率f增大迅速减小,随外电场幅值E0的增大迅速增大。表明随机取向薄膜中铁电畴在极化翻转过程中消耗的能量小,翻转的速度慢。
学位年度:2010
作者:李超
学位授予单位:青岛大学
关键词:Bi_4Ti_3O_(12);;薄膜;;原位外电场诱导;;取向生长;;铁电体;;回线动力学标度
摘要:
层状钙钛矿型铁电体Bi4Ti3O12的居里温度高,自发极化大，Ps靠近α轴。稀土掺杂的Bi4Ti3Oi2薄膜在金属电极上耐疲劳,是实现铁电存储器应用的最佳材料之一。人们希望能制备沿α轴(或近α轴)均匀取向生长(取向度超过95%)的Bi4Ti3Oi2基铁电薄膜,以便获得大的剩余极化。同时,为满足铁电存储器实用要求,很有必Neodymium Magnets要直接在金属电极上取向生长铁电薄膜。但是实验证明,要求钙钛矿型铁电薄膜在金属电极上均匀取向生长相当困难。
本论文在Bi4Ti3O12薄膜快速升温晶化时,通过原位外加电场诱导薄膜中晶粒取向成核,用sol-gel工艺直接在标准型(111)Pt/Ti/SiO2/Si(100)衬底上制备了高a/b轴择优取向的Bi4Ti3O12薄膜。较系统研究了外电场大小、升温速率及退火温度对Bi4Ti3O12薄膜择优取向生长的影响。结果表明,若铁电薄膜的居里温度高于其结晶温度,在薄膜晶化成核时,外电场的确可以有效地诱导晶粒取向成核,晶粒的自发极化倾向与外电场方向一致。在外电场2 kV,升温速率60℃/s,退火温度750℃时获得高a/b轴择优取向的Bi4Ti3O12薄膜,该薄膜电滞回线饱和,剩余极化2Pr值高达63μC·cm-2,由此估计其中沿a/b轴择优取向晶粒的体积分数约为62%。
对比研究了a/b轴择优取向和随机取向Bi4Ti3O12铁电薄膜的回线动力学标度。结果表明,a/b轴择优取向Bi4Ti3O12薄膜的回线面积<A>随外加电场的频率f和幅值E0的变化关系为：在低频段(外电场频率f＜1/τe时),标度关系为<A>∝f0.018E00.6；在高频段(外场频率f＞1/τe时),有标度关系<A>∝f-0.026E00.6。而随机取向Bi4Ti3O12薄膜的<A>随外加电场的变化关系在高频段和低频段可统一为<A>∝f-0.106E01.667。实验发现,a/b轴择优取向Bi4Ti3O12铁电薄膜的特征翻转时间τe随外电场幅值的增大而减小,回线饱和时其畴翻转特征时间为1.1 ms,而随机取向的薄膜中,在测试频率范围内无畴翻转的特征时间出现。两种不同取向薄膜标度关系的差异反映了a/b轴择优与随机取向薄膜中铁http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets电畴翻转的差异。与a/b轴择优取向Bi4Ti3O12薄膜相比,随机取向薄膜的回线面积<A>随频率f增大迅速减小,随外电场幅值E0的增大迅速增大。表明随机取向薄膜中铁电畴在极化翻转过程中消耗的能量小,翻转的速度慢。
学位年度:2010
掺杂锶铁氧体的结构与磁性能研究
题名:掺杂锶铁氧体的结构与磁性能研究
作者:容胜忠
学位授予单位:华南理工大学
关键词:锶铁氧体;;La-Co掺杂;;La-Zn掺杂;;纳米添加剂;;磁性能
摘要:
由于原料价格便宜、优异的化学稳定性,高的磁晶各向异性等一系列优点,锶铁氧体在微波设备﹑磁光﹑高密度磁记录介质等方面得到广泛的应用。近年来,随着汽车、通讯、办公用品、消费品等产品的轻便化和节能化,高Neodymium Magnets性能永磁铁氧体材料正逐渐成为人们研究的热点。
本文在Y30H-2预烧料基础上,采用陶瓷法制备了La-Co、La-Zn掺杂的高性能M型锶铁氧体。采用X射线衍射仪(XRD)、配有EDS的扫描电镜(SEM)、MATEST-2010H永磁(稀土)磁性材料自动测量仪等测试方法,系统地研究了样品的结构和磁性能,同时研究了不同粒度CaCO_3、SiO_2、Al_2O_3添加对锶铁氧体结构和性能的影响。
XRD及SEM分析结果表明,样品Sr_(1-x)La_xFe_(12-x)Co_xO_(19) (x≤0.30)在1100℃~1215℃烧结时,La~(3+)和Co~(2+)已经完全掺杂进入锶铁氧体相中。随着La-Co含量的增大,样品的B_r和H_(cj)都是先增大后减小。在1170℃烧结时,剩磁Br在x=0.12取得极大值,与未掺杂La-Co的样品相比,剩磁B_r增加了2.28%。在1170℃烧结时,H_(cj)的增幅最大,在x=0.15获得极大值,与未掺杂La-Co的样品相比,内禀矫顽力Hcj增大了24.29%。研究结果表明,La-Co联合掺杂能显著提高样品的H_(cj)。在x=0.15,1170℃烧结90分钟,实验获得最佳磁性能为:B_r=411.9mT,H_(cb)=291.3kA/m,H_(cj)=332.9kA/m,(BH)_(max)=31.9kJ/m~3。
采用正交试验,确定了小料添加剂(CaCO_3,SiO_2,H_3BO_3,SrCO_3)的配比含量,在此基础上制备了La-Zn掺杂的M型锶铁氧体Sr_(1-x)La_xFe_(12-x)Zn_xO_(19)(x≤0.27)。采用XRD及SEM分析表明,样品在1155℃~1215℃烧结时,La~(3+)和Zn~(2+)已经完全掺杂进入锶铁氧体相中。随着La-Zn含量的增加,样品的Br先增大后减小,而Hcj先急剧降低,在x≥0.12后,Hcj缓慢降低。在1200℃烧结时,样品在x=0.09取得http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets极大值,相对无掺杂样品Br增加了2.27%,La-Zn掺杂能有效的提高锶铁氧体的Br,却显著降低了锶铁氧体的Hcj。而在x=0.09,1200℃烧结时,La-Zn掺杂锶铁氧体取得最优磁性能:Br=427.3mT,Hcb=184.0kA/m,Hcj=189.0kA/m,(BH)max=33.8kJ/m~3。
不同粒度的CaCO_3、SiO_2、Al_2O_3添加剂对锶铁氧体磁性能的影响不同。研究表明,纳米添加剂比微米添加剂对锶铁氧体的磁性能的影响有更显著的效果。
学位年度:2010
作者:容胜忠
学位授予单位:华南理工大学
关键词:锶铁氧体;;La-Co掺杂;;La-Zn掺杂;;纳米添加剂;;磁性能
摘要:
由于原料价格便宜、优异的化学稳定性,高的磁晶各向异性等一系列优点,锶铁氧体在微波设备﹑磁光﹑高密度磁记录介质等方面得到广泛的应用。近年来,随着汽车、通讯、办公用品、消费品等产品的轻便化和节能化,高Neodymium Magnets性能永磁铁氧体材料正逐渐成为人们研究的热点。
本文在Y30H-2预烧料基础上,采用陶瓷法制备了La-Co、La-Zn掺杂的高性能M型锶铁氧体。采用X射线衍射仪(XRD)、配有EDS的扫描电镜(SEM)、MATEST-2010H永磁(稀土)磁性材料自动测量仪等测试方法,系统地研究了样品的结构和磁性能,同时研究了不同粒度CaCO_3、SiO_2、Al_2O_3添加对锶铁氧体结构和性能的影响。
XRD及SEM分析结果表明,样品Sr_(1-x)La_xFe_(12-x)Co_xO_(19) (x≤0.30)在1100℃~1215℃烧结时,La~(3+)和Co~(2+)已经完全掺杂进入锶铁氧体相中。随着La-Co含量的增大,样品的B_r和H_(cj)都是先增大后减小。在1170℃烧结时,剩磁Br在x=0.12取得极大值,与未掺杂La-Co的样品相比,剩磁B_r增加了2.28%。在1170℃烧结时,H_(cj)的增幅最大,在x=0.15获得极大值,与未掺杂La-Co的样品相比,内禀矫顽力Hcj增大了24.29%。研究结果表明,La-Co联合掺杂能显著提高样品的H_(cj)。在x=0.15,1170℃烧结90分钟,实验获得最佳磁性能为:B_r=411.9mT,H_(cb)=291.3kA/m,H_(cj)=332.9kA/m,(BH)_(max)=31.9kJ/m~3。
采用正交试验,确定了小料添加剂(CaCO_3,SiO_2,H_3BO_3,SrCO_3)的配比含量,在此基础上制备了La-Zn掺杂的M型锶铁氧体Sr_(1-x)La_xFe_(12-x)Zn_xO_(19)(x≤0.27)。采用XRD及SEM分析表明,样品在1155℃~1215℃烧结时,La~(3+)和Zn~(2+)已经完全掺杂进入锶铁氧体相中。随着La-Zn含量的增加,样品的Br先增大后减小,而Hcj先急剧降低,在x≥0.12后,Hcj缓慢降低。在1200℃烧结时,样品在x=0.09取得http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets极大值,相对无掺杂样品Br增加了2.27%,La-Zn掺杂能有效的提高锶铁氧体的Br,却显著降低了锶铁氧体的Hcj。而在x=0.09,1200℃烧结时,La-Zn掺杂锶铁氧体取得最优磁性能:Br=427.3mT,Hcb=184.0kA/m,Hcj=189.0kA/m,(BH)max=33.8kJ/m~3。
不同粒度的CaCO_3、SiO_2、Al_2O_3添加剂对锶铁氧体磁性能的影响不同。研究表明,纳米添加剂比微米添加剂对锶铁氧体的磁性能的影响有更显著的效果。
学位年度:2010
二氧化钛光催化剂改性及光催化性能的研究
题名:二氧化钛光催化剂改性及光催化性能的研究
作者:田皓
学位授予单位:山东师范大学
关键词:二氧化钛;;杭锦2#土;;氟化锂掺杂;;锶掺杂;;光催化;;溶胶-凝胶法
摘要:
1972年,日本学者藤岛昭和本多健一在n型半导体TiO_2电极上发现了水的光电催化分解作用。以此为契机,开始了多相催化研究的新纪元。半导体光催化氧化技术是一种新型的现代水处理技术,由于它能广泛地利用天然能源-太Neodymium Magnets阳能,且对多种有机物有明显的降解效果,因此具有广阔的应用前景。
但是以TiO_2为典型代表的光催化剂在传统方法上的应用存在着量子效率低以及回收困难等缺点而限制其工业化的推广应用,因此国内外学者积极展开了对这方面的系统研究,其中包括TiO_2催化剂的表面修饰、固载、重金属沉积、复合半导体、掺杂稀土元素等技术。
本课题旨在开展对二氧化钛与杭锦2~#土的复合条件以及光催化降解亚甲基蓝的研究,探索其最佳制备工艺条件及降解有机物的一般规律,以期进一步充实光催化剂的负载技术以及有机污水治理方面的研究,为光催化剂的工业化推广运用补充血液。
本论文主要由以下六部分组成:
第一部分:系统回顾了光催化材料的发展状况及优点,全面阐述了纳米TiO_2光催化技术在应用、改性、制备、载体等方http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets面的研究情况。
第二部分:将原杭锦2~#土经过杭锦2~#土的前处理、杭锦2~#土的活化、水洗分酸、干燥粉碎四个步骤制成活性白土。通过XRD和FTIR对样品进行了表征。
第三部分:以钛酸丁酯和活化土为原料,采用溶胶-凝胶法制备了一系列TiO_2/杭锦2~#土复合光催化剂。用XRD、FTIR、BET、SEM、XPS和TG等分析方法对复合光催化剂的物相组成、晶相等物化性质进行了表征。
第四部分:采用溶胶-凝胶法掺杂LiF和Sr分别制备了LiF-TiO_2/杭锦2~#土和Sr-TiO_2/杭锦2~#土复合光催化剂。用XRD和FTIR对催化剂进行了表征。
第五部分:以亚甲基蓝水溶液为光降解体系,在紫外光照射下,利用不同条件下制备的样品作为光催化剂进行光催化降解,考察了不同制备条件下的样品的光催化性能,并探索出复合光催化剂的最佳制备条件。
第六部分:结论及展望。
学位年度:2010
作者:田皓
学位授予单位:山东师范大学
关键词:二氧化钛;;杭锦2#土;;氟化锂掺杂;;锶掺杂;;光催化;;溶胶-凝胶法
摘要:
1972年,日本学者藤岛昭和本多健一在n型半导体TiO_2电极上发现了水的光电催化分解作用。以此为契机,开始了多相催化研究的新纪元。半导体光催化氧化技术是一种新型的现代水处理技术,由于它能广泛地利用天然能源-太Neodymium Magnets阳能,且对多种有机物有明显的降解效果,因此具有广阔的应用前景。
但是以TiO_2为典型代表的光催化剂在传统方法上的应用存在着量子效率低以及回收困难等缺点而限制其工业化的推广应用,因此国内外学者积极展开了对这方面的系统研究,其中包括TiO_2催化剂的表面修饰、固载、重金属沉积、复合半导体、掺杂稀土元素等技术。
本课题旨在开展对二氧化钛与杭锦2~#土的复合条件以及光催化降解亚甲基蓝的研究,探索其最佳制备工艺条件及降解有机物的一般规律,以期进一步充实光催化剂的负载技术以及有机污水治理方面的研究,为光催化剂的工业化推广运用补充血液。
本论文主要由以下六部分组成:
第一部分:系统回顾了光催化材料的发展状况及优点,全面阐述了纳米TiO_2光催化技术在应用、改性、制备、载体等方http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets面的研究情况。
第二部分:将原杭锦2~#土经过杭锦2~#土的前处理、杭锦2~#土的活化、水洗分酸、干燥粉碎四个步骤制成活性白土。通过XRD和FTIR对样品进行了表征。
第三部分:以钛酸丁酯和活化土为原料,采用溶胶-凝胶法制备了一系列TiO_2/杭锦2~#土复合光催化剂。用XRD、FTIR、BET、SEM、XPS和TG等分析方法对复合光催化剂的物相组成、晶相等物化性质进行了表征。
第四部分:采用溶胶-凝胶法掺杂LiF和Sr分别制备了LiF-TiO_2/杭锦2~#土和Sr-TiO_2/杭锦2~#土复合光催化剂。用XRD和FTIR对催化剂进行了表征。
第五部分:以亚甲基蓝水溶液为光降解体系,在紫外光照射下,利用不同条件下制备的样品作为光催化剂进行光催化降解,考察了不同制备条件下的样品的光催化性能,并探索出复合光催化剂的最佳制备条件。
第六部分:结论及展望。
学位年度:2010
以开链冠醚型羧酸与含氮模板的混配自组装及其可调谐荧光性质研究
题名:以开链冠醚型羧酸与含氮模板的混配自组装及其可调谐荧光性质研究
作者:任淑奎
学位授予单位:山东师范大学
关键词:自组装;;开链冠醚;;水热合成;;含N模板;;可调谐发光;;刻蚀
摘要:
以配位作用为驱动力的有机-无机超分子配位化学是目前国际化学界最活跃、最前沿的研究领域之一,亦是合成新型有机-无机复合功能材料的最有效的途径之一。最近,人们在配位聚合物的研究上取得了重要的进展,合成和表征了许多具有一维、二维和三维网状结构的配位聚合物。本文合成了一系列结构新颖的开链冠醚桥联的羧酸类、氰基类及吡啶类配体,研究它们在水热及溶剂条件下与金属离子的自组Neodymium Magnets装化学。合成了37个新型的配位聚合物,并通过X-射线单晶衍射、红外、元素分析表征了它们的结构,测定了部分化合物的荧光、热重分析等性质。
一、合成了一系列单甘醇醚桥联的开链冠醚型羧酸,研究了它们在含氮模板存在下与Co(II)、Ni(II)和Pb(II)等金属的配位化学,合成了12个结构新颖的配位聚合物,并讨论了含氮模板、分子间弱作用力对合成的配位化合物结构的影响。
二、合成了一系列多甘醇醚桥联的开链冠醚型羧酸,研究了它们在含氮模板存在下与Mn(II)、Co(II)、Ni(II)和Pb(II)等金属的配位化学,合成了18个结构新颖的配位化合物,讨论了配体的配位构型、含氮模板及分子间弱作用力对合成的配位化合物结构的影响,并讨论了它们的固态荧光性质。
三、设计合成了以开链冠醚羧酸配体L6和4, 4’-联吡啶(4, 4’-bpy)混和体系的金属-有机超分子框架,该聚合物具有光致变色的性质。并首次采用刻蚀方法(以有机溶剂滤除4, 4’-联吡啶分子)得到了具有开放隧道的类冠醚配位聚合物,通过引入不同的稀土离子实现了双波段发光(同一激发波长)和双区域可调谐发光(http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets不同激发波长)。以L6和L8与1, 2-二(4-吡啶)乙烯(tdpe)和4, 4’-联吡啶(4, 4’-bpy)及金属离子分别自组装,也合成了可通过刻蚀方法得到具有开放隧道的类冠醚配位聚合物,并进行了初步研究。
四、合成了一系列开链冠醚桥联的氰基类及吡啶类配体,研究了它们与Ag(I)、Pd(II)、Hg(II)等金属的配位化学,合成了4个结构新颖的配位化合物,并讨论了溶剂分子对合成的配位化合物结构的影响。
我们设计合成了一系列开链冠醚桥联的羧酸类、氰基类及吡啶类配体,研究结果表明这些配体是构建结构新颖配位化合物的良好前体,它们与金属离子的自组装反应能够得到结构新颖,物化性质优良的配位化合物,为设计合成荧光材料及功能性材料奠定了实验基础。另外,得到的结构新颖的超分子组装体可通过刻蚀得到富氧隧道,为主客体化学的研究提供了条件。
学位年度:2010
作者:任淑奎
学位授予单位:山东师范大学
关键词:自组装;;开链冠醚;;水热合成;;含N模板;;可调谐发光;;刻蚀
摘要:
以配位作用为驱动力的有机-无机超分子配位化学是目前国际化学界最活跃、最前沿的研究领域之一,亦是合成新型有机-无机复合功能材料的最有效的途径之一。最近,人们在配位聚合物的研究上取得了重要的进展,合成和表征了许多具有一维、二维和三维网状结构的配位聚合物。本文合成了一系列结构新颖的开链冠醚桥联的羧酸类、氰基类及吡啶类配体,研究它们在水热及溶剂条件下与金属离子的自组Neodymium Magnets装化学。合成了37个新型的配位聚合物,并通过X-射线单晶衍射、红外、元素分析表征了它们的结构,测定了部分化合物的荧光、热重分析等性质。
一、合成了一系列单甘醇醚桥联的开链冠醚型羧酸,研究了它们在含氮模板存在下与Co(II)、Ni(II)和Pb(II)等金属的配位化学,合成了12个结构新颖的配位聚合物,并讨论了含氮模板、分子间弱作用力对合成的配位化合物结构的影响。
二、合成了一系列多甘醇醚桥联的开链冠醚型羧酸,研究了它们在含氮模板存在下与Mn(II)、Co(II)、Ni(II)和Pb(II)等金属的配位化学,合成了18个结构新颖的配位化合物,讨论了配体的配位构型、含氮模板及分子间弱作用力对合成的配位化合物结构的影响,并讨论了它们的固态荧光性质。
三、设计合成了以开链冠醚羧酸配体L6和4, 4’-联吡啶(4, 4’-bpy)混和体系的金属-有机超分子框架,该聚合物具有光致变色的性质。并首次采用刻蚀方法(以有机溶剂滤除4, 4’-联吡啶分子)得到了具有开放隧道的类冠醚配位聚合物,通过引入不同的稀土离子实现了双波段发光(同一激发波长)和双区域可调谐发光(http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets不同激发波长)。以L6和L8与1, 2-二(4-吡啶)乙烯(tdpe)和4, 4’-联吡啶(4, 4’-bpy)及金属离子分别自组装,也合成了可通过刻蚀方法得到具有开放隧道的类冠醚配位聚合物,并进行了初步研究。
四、合成了一系列开链冠醚桥联的氰基类及吡啶类配体,研究了它们与Ag(I)、Pd(II)、Hg(II)等金属的配位化学,合成了4个结构新颖的配位化合物,并讨论了溶剂分子对合成的配位化合物结构的影响。
我们设计合成了一系列开链冠醚桥联的羧酸类、氰基类及吡啶类配体,研究结果表明这些配体是构建结构新颖配位化合物的良好前体,它们与金属离子的自组装反应能够得到结构新颖,物化性质优良的配位化合物,为设计合成荧光材料及功能性材料奠定了实验基础。另外,得到的结构新颖的超分子组装体可通过刻蚀得到富氧隧道,为主客体化学的研究提供了条件。
学位年度:2010
2012年1月16日星期一
Research of Self-Reconfigurable Robot Based on Universal Joint Module
Research of Self-Reconfigurable Robot Based on Universal Joint Module
The modular self-reconfigurable (SR) robot system is composed of the standard modules, each of which can connect with or disconnect to the adjacent modules, communicate with each other and capable of locomotion and communication. Usually, a single module is not flexible enough to do too much by itself, but a collection of modules can remarkably strength the function of the system, as they can be organized as the most suitable geometric structure under the local environmental conditions to perform variety of tasks through changing the connection position and locative relations. Compared with the traditional robots, the modular self-reconfigurable robots can move in many kinds of ways and have http://www.999magnet.com/products/131-magnetic-lifter a lot of advantages, such as: modularization, self-deformation, self-replication, self-repairing. The SR robots can perform outstanding advantages in the unstructured environment, and have broad application prospects especially in the uncontrolled environment with variety of complicated tasks, such as: space exploration, emergency search and rescue, nuclear power plant maintenance. As the self-reconfigurable robots have great abilities in deformation and environmental adaptability, they have interested researchers all over the world. Therefore, researching in the SR robots system in time should play an important part both in theoretic and practicality, as the research can raise the level of the SR robot research of our country and make applying the SR robots in rescuing and space exploration early.The SR robots can perform outstanding advantages in the unstructured environment, and have broad application prospects especially in the uncontrolled environment with variety of complicated tasks, such as: space exploration, emergency search and rescue, nuclear power plant maintenance. As the self-reconfigurable robots have great abilities in deformation and environmental adaptability, they have interested researchers all over the world. Therefore, researching in the SR robots system in time should play an important part in advancingThe module is the elementary unit of the SR robot system. The function of the module directly determines the locomotion and reconfiguration abilities of the SR robots, and then influences the control system, reconfigurable algorithm and the motional complexity of the modular robot system. From the characteristics of the SR robots, a new design method has been proposed. Through analysis and comparison of the modules with different degrees of freedom configuration, we determined a new combination program of the shape and the DOF configuration. A new SR robot system, namely UBot, has been proposed, each of which is based on universal joint and has two rotational degrees of freedom. The UBot system can perform as both lattice-type and chain-type SR robot system. The UBot module has regular cubic shape and is composed of two L-type parts connected by a right angle shaft. Each module has two independent joints around the right angle shaft and four connecting surfaces. The active and passive hook-type connecting systems have been proposed, which can connect to or disconnect from the adjacent modules quickly and reliably.The mechanism has the function of self-lock and energy-saving, and mutually opposite polarity of the permanent magnets located on the surface of each connecting surface make pre-position for the connecting. The battery is embedded inside the module, and wireless communication technology has been employed. To solve the problem of the cable wound, the wires go through the center of the right angle shaft between two parts. The connecting mechanism and the module substrate have been connected with full contact connection, so the maintenance of the modules is more convenient.Through the deep analysis of the UBot module’characteristic, a topological description method based on correlation matrix has been proposed. The method fully describes the joint angles’states, the connecting relations and the location information of the modules. The configuration recognition method has been proposed based on the graph theory. The automatic matching of the new configuration and the configuration from database has been implemented through analysis and computation of the adjacency matrix and the connection orientation matrix of the configuration. Consequently, all the possible moving gaits can be mapped to the new configuration. The restrictions in the process of reconfiguration and deformation of the UBot self-reconfiguration system have been analysed. The hypothetical conditions of the reconfiguration and deformation have been proposed. According to the characteristic of the UBot module, a necessity criterion which can judge whether the configurations can be reconstructed between each other has been proposed. The criterion can remove a portion of configurations which can’t be deformed to each other, and avoid the meaningless operation of the deformation. This criterion can also be applied to other SR robot system the modules of which are cubic and only have rotational degrees of freedom. For the reconfiguration and deformation between the fixed configurations, a deformation planning method that makes the degree of the configuration similarity as the search-driven function has been proposed. The method Magnet lifter can find a deformation path which needs a relatively less steps within a reasonable time. The method has been used in the deformation from the quadruped configuration to the worm-like configuration and has been verified through the simulation. The locomotion of some typical configurations composed of UBot modules has been researched. The linear motion and rotary motion of the Omni-directional mobile cross configuration have been controlled in static gait planning, respectively. The motion control method of the static rolling locomotion and the dynamic rolling locomotion of the ring configuration has been proposed based on the theory of the floating four-bar linkage. The control method can be extended to control the locomotion of any ring configuration made of arbitrary modules. The dynamic rolling gait has been optimized and simulated. Through optimizing and simulating the dynamic rolling gait, the best combination of the ring angle and the deformation rate has been determined. Crawling gait and in-situ rotation gait of the quadruped configuration have been planned and have been verified through the result of simulation. Finally, the general motion planning function of the worm-configuration and the snake-like configuration composed of arbitrary number of modules has been proposed.The self-reconfigurable robot experiment has been established. The deformation experiment from three-limbed configuration to worm-like configuration and the coordinated movement experiment of cross configuration, ring configuration, quadruped configuration and single chain series-connection configuration have been completed. The results have proved that the UBot system has strong capabilities of reconfiguration and coordinated movement, and also verified the correctness of the proposed reconfiguration and coordinated motion planning. 更多还原
2012年1月13日星期五
Research on Recognition of Electromagnetic Noise and Vibration of Permanent Magnet Synchronous Machine
Research on Recognition of Electromagnetic Noise and Vibration of Permanent Magnet Synchronous Machine
It is well known that noise and vibration of permanent magnet synchronous machines (PMSM) are important targets used to estimate operation performance, which have also been difficult problems. Through the research on identification technique to noise and vibration source, the design scheme of PMSM is optimized or the maximum noise and vibration source is identified when it is working. So the useful method is adopted to decrease the noise and vibration. It is significant for improving the performance of machines, shortening development cycle and decreasing cost.As the innovation team project of LiaoNing province (2006T100), the effect on noise and vibration Neodymium Magnets source supplied by sine wave and inverter are researched, and the eigenfrequency of air gap magnetic field, normal electromagnetic force, noise and vibration are investigated. Some theoretical significances and practical values are obtained as follow:Firstly, the air gap magnetic field and normal electromagnetic force supplied by sine wave and inverter are analyzed. The regularity between inverter switching frequency and stator current harmonic frequency is summarized by experiments, and the expressions of air gap magnetic field frequency and inverter switching frequency is deduced by 3D motional magnetic field Finite Element Method (FEM) calculation and analysis. Then the regularity of pole-slot match effecting on normal electromagnetic force wave order is analyzed, and the analytical expressions of normal electromagnetic force wave order resulting from integral and fractional slot winding is obtained.
The analytical expressions of normal electromagnetic force wave order and frequency supplied by inverter is deduced.Secondly, the regularity of normal and tangential electromagnetic force effecting on electromagnetic noise and vibration of PMSM is investigated, and the program of electromagnetic noise calculation is compiled. The normal electromagnetic force is the main reason of noise and vibration by analysis, the vibration of PMSM is caused by cogging torque, but it has a little influence on noise. The electromagnetic noise calculation program is suitable for comparison of multi-schemes, and the calculation is accurate and timesaving. Then the effect on noise and vibration source due to eccentricity is analyzed, the expressions of normal electromagnetic force and eigenfrequency of noise and vibration under condition of static eccentricity and dynamic eccentricity.Thirdly, the transient acoustic field FEM of PMSM is investigated, and the experiment characteristic is analyzed. The spectrum of experimental stator current supplied by inverter is analyzed, and the time http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets current harmonic loaded in stator winding, so 3D motional magnetic field of PMSM supplied by inverter is calculated. Using normal electromagnetic force instead of air-gap flux density by the Maxwell’s Law, and then applied it on the surface of stator in order to calculating the transient acoustic field supplied by inverter. Because the air-gap magnetic field harmonic content depends on pole-slot match, which effects acoustic field peak frequency, so the effect of integral and fractional slot winding on air-gap magnetic field and 2D acoustic field are calculated and analyzed by FEM.Fourthly, through analysis for mechanism of noise and vibration and eigenfrequency expressions, the identification program for source of noise and vibration is compiled. The time domain signal of noise and vibration is analyzed by this, the noise and vibration source, which results in peak frequency of noise and vibration, can be identified. So the relevant method can be adopted to decrease the noise and vibration of PMSM.
It is well known that noise and vibration of permanent magnet synchronous machines (PMSM) are important targets used to estimate operation performance, which have also been difficult problems. Through the research on identification technique to noise and vibration source, the design scheme of PMSM is optimized or the maximum noise and vibration source is identified when it is working. So the useful method is adopted to decrease the noise and vibration. It is significant for improving the performance of machines, shortening development cycle and decreasing cost.As the innovation team project of LiaoNing province (2006T100), the effect on noise and vibration Neodymium Magnets source supplied by sine wave and inverter are researched, and the eigenfrequency of air gap magnetic field, normal electromagnetic force, noise and vibration are investigated. Some theoretical significances and practical values are obtained as follow:Firstly, the air gap magnetic field and normal electromagnetic force supplied by sine wave and inverter are analyzed. The regularity between inverter switching frequency and stator current harmonic frequency is summarized by experiments, and the expressions of air gap magnetic field frequency and inverter switching frequency is deduced by 3D motional magnetic field Finite Element Method (FEM) calculation and analysis. Then the regularity of pole-slot match effecting on normal electromagnetic force wave order is analyzed, and the analytical expressions of normal electromagnetic force wave order resulting from integral and fractional slot winding is obtained.
The analytical expressions of normal electromagnetic force wave order and frequency supplied by inverter is deduced.Secondly, the regularity of normal and tangential electromagnetic force effecting on electromagnetic noise and vibration of PMSM is investigated, and the program of electromagnetic noise calculation is compiled. The normal electromagnetic force is the main reason of noise and vibration by analysis, the vibration of PMSM is caused by cogging torque, but it has a little influence on noise. The electromagnetic noise calculation program is suitable for comparison of multi-schemes, and the calculation is accurate and timesaving. Then the effect on noise and vibration source due to eccentricity is analyzed, the expressions of normal electromagnetic force and eigenfrequency of noise and vibration under condition of static eccentricity and dynamic eccentricity.Thirdly, the transient acoustic field FEM of PMSM is investigated, and the experiment characteristic is analyzed. The spectrum of experimental stator current supplied by inverter is analyzed, and the time http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets current harmonic loaded in stator winding, so 3D motional magnetic field of PMSM supplied by inverter is calculated. Using normal electromagnetic force instead of air-gap flux density by the Maxwell’s Law, and then applied it on the surface of stator in order to calculating the transient acoustic field supplied by inverter. Because the air-gap magnetic field harmonic content depends on pole-slot match, which effects acoustic field peak frequency, so the effect of integral and fractional slot winding on air-gap magnetic field and 2D acoustic field are calculated and analyzed by FEM.Fourthly, through analysis for mechanism of noise and vibration and eigenfrequency expressions, the identification program for source of noise and vibration is compiled. The time domain signal of noise and vibration is analyzed by this, the noise and vibration source, which results in peak frequency of noise and vibration, can be identified. So the relevant method can be adopted to decrease the noise and vibration of PMSM.
Research on PM Ring Torque Motor and Its Control Strategy Used in Direct Drive NC Table
Research on PM Ring Torque Motor and Its Control Strategy Used in Direct Drive NC Table
Numerical control (NC) table is one of the most important assemblies in multiaxial linkage NC machine. It is acknowledged that the elastic distortion, friction, backlash , and any other problems resulting from mechanical drive chain are shown on the traditional drive NC table. The direct drive NC table not only resolves the above problems but also has many advantages, such as high torque, quick response ability, high position precision, and so on. In recent years, the direct drive NC table assembly is the research hot spot in multiaxial linkage high-grade NC machine field. Therefore, taking permanent magnet (PM) ring torque motor and its control strategy used in direct drive NC table as subjects, the key technologie of subjects is dicussed in this dissertation.To satisfy the drive motor requirements of low torque ripple and high torque density, used in the NC table, the similar pole and slot number outer-rotor PM ring torque motor with unequal teeth tips width and alternate winding is researched and Neodymium Magnets designed based on the design theory of multipolar fractional-slot motor. The structure of similar pole and slot number can increase the winding pitch coefficient, and reduce cogging torque ripple effectively with the reasonable combination of pole number and slot number. The alternate winding and unequal teeth tips width structure optimize the stator teeth flux linkage and winding coefficient, as a result, the torque density is increased. Furthermore, the influences of unequal teeth tips width and alternate winding structure on the harmonic torque and cogging torque are analyzed.In order to increase the output torque ability of table motor further, combining the special requirements of direct drive NC table mechanical structure, the dual-synchronous dual-rotor PM ring torque motor with series connection structure is researched. The new dual-rotor table motor structure with better ability of heat dissipation, resolves the heat dissipation problem of high torque table motor to some extent and increases the torque density.
And it also resolves the synchronous control and power distribution problems between the two independent motors of traditional double-drive mode.Based on dual-rotor PM ring torque motor structure characteristics, the generating rule of dual-rotor motor cogging torque is researched further. On the basis of this analysis, the reduction principle of dual-rotor motor cogging torque with phase-shifting technology is studied, and the reduction principle of cogging torque by combination of inner and outer slot notch width is also analysed. The optimal phase-shifting angle calculation formulas both in equal teeth tips motor and unequal teeth tips motor are obtained by analytic calculation method. And the dual-rotor PM ring torque methmatical model is also established.In the aspect of control strategy, aiming at the periodic input signal tracking problem of the PM ring torque motor, a plug-in type repetitive controller is designed. On this basis, in order to improve the robustness against load disturbances and parameter variations, the control method of repetitive control combining withμ(structured singular value) theory is researched. The robust repetitive control problem is transformed into H∞optimal control problem using linear fractional transformation(LFT). The D-K iteration is used to design the robust repetitive controller, which realized the stability, the robustness and improved the tracking precision of the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets servo system.In the end, the outer-rotor PM ring torque motor with unequal teeth tips width and alternate winding structure is produced, and the direct drive NC table combining reasonable mechanical structure design is also produced. Consequently, the many prototype experiments are completed, such as noload torque ripple experiment, load torque performance experiment. The table experiment system is established using digital signal processor TMS320LF2407A. The position tracking experiments are completed under the conditions of noload, load disturbance, and rotational inertia parameter variations repectively. All the experiments results prove that the motor design scheme and control strategy are reasonable and correct.
Numerical control (NC) table is one of the most important assemblies in multiaxial linkage NC machine. It is acknowledged that the elastic distortion, friction, backlash , and any other problems resulting from mechanical drive chain are shown on the traditional drive NC table. The direct drive NC table not only resolves the above problems but also has many advantages, such as high torque, quick response ability, high position precision, and so on. In recent years, the direct drive NC table assembly is the research hot spot in multiaxial linkage high-grade NC machine field. Therefore, taking permanent magnet (PM) ring torque motor and its control strategy used in direct drive NC table as subjects, the key technologie of subjects is dicussed in this dissertation.To satisfy the drive motor requirements of low torque ripple and high torque density, used in the NC table, the similar pole and slot number outer-rotor PM ring torque motor with unequal teeth tips width and alternate winding is researched and Neodymium Magnets designed based on the design theory of multipolar fractional-slot motor. The structure of similar pole and slot number can increase the winding pitch coefficient, and reduce cogging torque ripple effectively with the reasonable combination of pole number and slot number. The alternate winding and unequal teeth tips width structure optimize the stator teeth flux linkage and winding coefficient, as a result, the torque density is increased. Furthermore, the influences of unequal teeth tips width and alternate winding structure on the harmonic torque and cogging torque are analyzed.In order to increase the output torque ability of table motor further, combining the special requirements of direct drive NC table mechanical structure, the dual-synchronous dual-rotor PM ring torque motor with series connection structure is researched. The new dual-rotor table motor structure with better ability of heat dissipation, resolves the heat dissipation problem of high torque table motor to some extent and increases the torque density.
And it also resolves the synchronous control and power distribution problems between the two independent motors of traditional double-drive mode.Based on dual-rotor PM ring torque motor structure characteristics, the generating rule of dual-rotor motor cogging torque is researched further. On the basis of this analysis, the reduction principle of dual-rotor motor cogging torque with phase-shifting technology is studied, and the reduction principle of cogging torque by combination of inner and outer slot notch width is also analysed. The optimal phase-shifting angle calculation formulas both in equal teeth tips motor and unequal teeth tips motor are obtained by analytic calculation method. And the dual-rotor PM ring torque methmatical model is also established.In the aspect of control strategy, aiming at the periodic input signal tracking problem of the PM ring torque motor, a plug-in type repetitive controller is designed. On this basis, in order to improve the robustness against load disturbances and parameter variations, the control method of repetitive control combining withμ(structured singular value) theory is researched. The robust repetitive control problem is transformed into H∞optimal control problem using linear fractional transformation(LFT). The D-K iteration is used to design the robust repetitive controller, which realized the stability, the robustness and improved the tracking precision of the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets servo system.In the end, the outer-rotor PM ring torque motor with unequal teeth tips width and alternate winding structure is produced, and the direct drive NC table combining reasonable mechanical structure design is also produced. Consequently, the many prototype experiments are completed, such as noload torque ripple experiment, load torque performance experiment. The table experiment system is established using digital signal processor TMS320LF2407A. The position tracking experiments are completed under the conditions of noload, load disturbance, and rotational inertia parameter variations repectively. All the experiments results prove that the motor design scheme and control strategy are reasonable and correct.
Study of Dynamics Decoupling Control and Electrifying Strategy of Permanent Magnet Spherical Motor
Study of Dynamics Decoupling Control and Electrifying Strategy of Permanent Magnet Spherical Motor
One kind of Permanent Magnet Spherical Motor (PMSM) is proposed in this paper, and the mechanical structure of each part is discussed first. Dynamical modeling of PMSM is made, and model errors, including structured uncertainties and unstructured uncertainties, are analyzed. According to the fact that there exist lots of inter-axis nonlinear couplings in its dynamic model, dynamic decoupling algorithms based on fuzzy controllers is proposed. In order to eliminate the effects of inter-axis couplings in the dynamic model, the dynamic decoupling algorithm with neural network identifier and ANFIS is proposed then. The two proposed algorithms, in which Computed Torque Method (CTM) structure is employed, can eliminate the couplings and improve the static and dynamic performances of the control system. Simulations verify the effectiveness of the proposed algorithms.A Neodymium Magnets spherical planning based electrifying strategy of PMSM is proposed. First, the Finite Elements Method (FEM) is employed to obtain the static torque model of PMSM.
Then the region with stator coils shaded on Stator Spherical Surface is spherically planned and divided into four classes of sub-regions, which can be analytically expressed. All stator coils are labeled according to similar triangle principle. Finally, static torque model is employed and linear equations are solved to obtain the electrifying stator coils and the electrifying currents. PMSM can realize complex trajectory tracking operations under different algorithms with the proposed electrifying strategy applied. The simulations are made, and the effectiveness of the proposed electrifying strategy is verified.With regards to the inverse kinematics problem of PMSM, analytically solving methods are complicated relatively. Solving methods of inverse kinematics based on feed forward neural network and that based on Advanced Ant Colony Algorithm (AACA) is proposed separately. Through the study of training data, neural network can approach the inverse model. According to the learn effects of training data with L-M algorithm applied, the optimum structure of the neural network for the inverse kinematics problem is determined. The AACA is then proposed to solve the inverse kinematics problem. the advantages of AACA are verified, and the parameters’configurations of AACA are http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets discussed according to the solving effects.According to the mechanical structure of PMSM, each main part of hardware circuit are discussed, and the hardware experiment platform based on TMS320F2812 DSP is built. Through the detection of rotor’s position and bus current, the hardware platform can realize two closed-loops speed regulations with rapid start and stable operation.
One kind of Permanent Magnet Spherical Motor (PMSM) is proposed in this paper, and the mechanical structure of each part is discussed first. Dynamical modeling of PMSM is made, and model errors, including structured uncertainties and unstructured uncertainties, are analyzed. According to the fact that there exist lots of inter-axis nonlinear couplings in its dynamic model, dynamic decoupling algorithms based on fuzzy controllers is proposed. In order to eliminate the effects of inter-axis couplings in the dynamic model, the dynamic decoupling algorithm with neural network identifier and ANFIS is proposed then. The two proposed algorithms, in which Computed Torque Method (CTM) structure is employed, can eliminate the couplings and improve the static and dynamic performances of the control system. Simulations verify the effectiveness of the proposed algorithms.A Neodymium Magnets spherical planning based electrifying strategy of PMSM is proposed. First, the Finite Elements Method (FEM) is employed to obtain the static torque model of PMSM.
Then the region with stator coils shaded on Stator Spherical Surface is spherically planned and divided into four classes of sub-regions, which can be analytically expressed. All stator coils are labeled according to similar triangle principle. Finally, static torque model is employed and linear equations are solved to obtain the electrifying stator coils and the electrifying currents. PMSM can realize complex trajectory tracking operations under different algorithms with the proposed electrifying strategy applied. The simulations are made, and the effectiveness of the proposed electrifying strategy is verified.With regards to the inverse kinematics problem of PMSM, analytically solving methods are complicated relatively. Solving methods of inverse kinematics based on feed forward neural network and that based on Advanced Ant Colony Algorithm (AACA) is proposed separately. Through the study of training data, neural network can approach the inverse model. According to the learn effects of training data with L-M algorithm applied, the optimum structure of the neural network for the inverse kinematics problem is determined. The AACA is then proposed to solve the inverse kinematics problem. the advantages of AACA are verified, and the parameters’configurations of AACA are http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets discussed according to the solving effects.According to the mechanical structure of PMSM, each main part of hardware circuit are discussed, and the hardware experiment platform based on TMS320F2812 DSP is built. Through the detection of rotor’s position and bus current, the hardware platform can realize two closed-loops speed regulations with rapid start and stable operation.
Position Sensorless Control of Permanent Magnetic Bearingless Synchronous Motor Based on Grey Model
Position Sensorless Control of Permanent Magnetic Bearingless Synchronous Motor Based on Grey Model
The bearingless motor, which hybridizes the advantage of torque and magnetic bearings control, is one of the research fields of high and superhigh speed motor. It has been attacted extensive interesting in demestic and abroad. Because of the advantage of high reliability, easy to manufacture, and simple structure, the permanent magnetic bearingless synchronous motor is found to be applied successfully in many fields, for instance, the semiconductor and life science.Sensorless technology of permanent magnetic bearingless synchronous motor has the advantages of high reliability, low cost, short shaft length and small system size; it is suitable for high speed and high power operation, which can improve the dynamic performance of the system. It is difficult to measure the rotor position when the permanent magnetic bearingless synchronous motor works in high or super high speed. Then the Neodymium Magnets rotor position sensorless technology can be applied to get the position information. Until now, a lot of work has been done on the position sensorless technology; it is mainly concentrated on low speed. The main purpose of this dissertation is to study position sensorless technology.In this dissertation the principle of the permanent magnetic bearingless synchronous motor was stated firstly, then given the mathematical model of permanent magnetic bearingless synchronous motor and analyzes the rotor flux orientation vector control system accordingly. Based on the above points, the dissertation mainly studies on the grey model estimation and system identification estimation method.
The above two mathematical models are used to study on the principle of position estimation. The two sensorless control strategies both have the abilities to implemente the sensorless control, one is permanent magnetic bearingless synchronous motor based on grey model using analytic method and the other is permanent magnetic bearingless synchronous motor based grey model using identification method. However, both strategies are dependent on motor parameters. In the mean while the motor temperature and the magnetic saturation have an impact on the control quality online parameter identification can be a good solution to this problem. In this paper,the initial position of rotor can be obtained by detecting the current change rate of winding coil which is connected to DC pulse when the stator core to reach saturation and the stator windings inductance decreases. Detection of the initial rotor position based on the using of the grey model identification method combined with parameter identification of the establishment of permanent magnet synchronous motor without bearing parameter http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets identification online Sensorless control strategy. Then the principle is validated by the simulation in different speeds. The dissertations also modify these two methods to solve the problems during the simulation. After the simulation, the application of the position sensorless technology in the vector control of the permanent magnetic bearingless synchronous motor is coming true.According to the strategy of the position sensorless control proposed in this dissertation, the double DSP sensorless control system of permanent magnetic bearingless synchronous motor is designed which use DSP (TMS320LF2407A) as main control chip and use TMS320VC33 as assistant control chip.
The bearingless motor, which hybridizes the advantage of torque and magnetic bearings control, is one of the research fields of high and superhigh speed motor. It has been attacted extensive interesting in demestic and abroad. Because of the advantage of high reliability, easy to manufacture, and simple structure, the permanent magnetic bearingless synchronous motor is found to be applied successfully in many fields, for instance, the semiconductor and life science.Sensorless technology of permanent magnetic bearingless synchronous motor has the advantages of high reliability, low cost, short shaft length and small system size; it is suitable for high speed and high power operation, which can improve the dynamic performance of the system. It is difficult to measure the rotor position when the permanent magnetic bearingless synchronous motor works in high or super high speed. Then the Neodymium Magnets rotor position sensorless technology can be applied to get the position information. Until now, a lot of work has been done on the position sensorless technology; it is mainly concentrated on low speed. The main purpose of this dissertation is to study position sensorless technology.In this dissertation the principle of the permanent magnetic bearingless synchronous motor was stated firstly, then given the mathematical model of permanent magnetic bearingless synchronous motor and analyzes the rotor flux orientation vector control system accordingly. Based on the above points, the dissertation mainly studies on the grey model estimation and system identification estimation method.
The above two mathematical models are used to study on the principle of position estimation. The two sensorless control strategies both have the abilities to implemente the sensorless control, one is permanent magnetic bearingless synchronous motor based on grey model using analytic method and the other is permanent magnetic bearingless synchronous motor based grey model using identification method. However, both strategies are dependent on motor parameters. In the mean while the motor temperature and the magnetic saturation have an impact on the control quality online parameter identification can be a good solution to this problem. In this paper,the initial position of rotor can be obtained by detecting the current change rate of winding coil which is connected to DC pulse when the stator core to reach saturation and the stator windings inductance decreases. Detection of the initial rotor position based on the using of the grey model identification method combined with parameter identification of the establishment of permanent magnet synchronous motor without bearing parameter http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets identification online Sensorless control strategy. Then the principle is validated by the simulation in different speeds. The dissertations also modify these two methods to solve the problems during the simulation. After the simulation, the application of the position sensorless technology in the vector control of the permanent magnetic bearingless synchronous motor is coming true.According to the strategy of the position sensorless control proposed in this dissertation, the double DSP sensorless control system of permanent magnetic bearingless synchronous motor is designed which use DSP (TMS320LF2407A) as main control chip and use TMS320VC33 as assistant control chip.
Research and Design on a Permanent Magnet Electrical Machine Combined with a Magnetic Gear
Research and Design on a Permanent Magnet Electrical Machine Combined with a Magnetic Gear
A novel magnetic field modulation gearing transmits torque by magnetic force with high density and efficiency, and could be a potential substitute of a mechanical gearing if used in lustration, low temperature, high altitude environment etc. The development of high performance rare-earth permanent magnet material and its successful application in electrical machine, make it possible to provide more torque density and efficiency for a modern permanent magnet machine compared with for an induction motor.A permanent magnet electrical machine combined with a field modulation magnetic gear has been presented in this paper. The paper describes the fundamental structure of an outer rotor brushless PM motor is embedded into a novel magnetic gear. Merits of the permanent Neodymium Magnets magnet electrical machine and the novel magnetic gear are combined together for realizing a high toque low speed drive.
The research results application prospect is widespread, may be applied in the military domain (ship direct drive), the transportation (electric locomotive, electric automobile direct drive), the renewable energy development (wind power generation), the advanced manufacturing industry (machine tool direct drive) and so on.As one part of the national 863 program research project“Research on an efficient large torque direct-drive permanent magnet combined electrical machine system”(2007 AA05Z233),The text concentrates on the design of a permanent magnet electrical machine combined with a magnetic gear.This article around a permanent magnet electrical machine combined with a magnetic gear expands research, do the following tasks:1) Base upon the analytical approach of electromagnetic field as a starting point, in cylindrical coordinates find the analytical solution of Laplace’s equation in a certain annular region of the air gap. Combine the finite element method, solve overall field vector potentials in an electrical machine, and lay the foundation to calculate other physical quantities.2) Analyze deficiencies of mechanical gears and traditional magnetic gears, research magnetic field modulation magnetic gearing which is the key part of the combined electrical machine work. For the characteristic of the device with two layers of air gap, whose input rotor and output rotor turn reversely, extend numerical and analytical combined method of magnetic field calculation, and establish the corresponding program. Both in inner layer air gap and in outer layer air gap the magnetic field has many kinds of harmonic component existence, but the electromagnetic torque is nearly the sole fundamental wave ingredient, the calculation result by way of numerical and analytical combined method is consistent with the theoretical analysis.
3) After using the inner rotor’s space of the field modulation magnetic gear, considering processing, assembly and so on feasibility, has completed the electrical machinery topology innovation, i.e., designed the permanent magnet electrical machine combined with the novel magnetic gear. With the aid of the numerical and analytical combined method, has realized the magnetic field calculation under the condition that the inner rotor and the outer rotor rotate with free pace and different direction. Parameters of the induced electromotive force and the electromagnetic torque and so on of the novel motor have been calculated, and it is not difficult to catch the maximum value of cogging torque. Has designed a low speed big torque highly effective electrical machine combined with a novel magnetic gear according to certain target requests, and developed the prototype.4) The experiment has proven the union of a novel magnetic gear and a permanent magnet electrical machine in the structure innovation successfully. The electrical machine combined with a novel magnetic gear runs at a high torque density http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets with a stable movement effect. The high torque density, the high transmission efficiency and stable movement result of the magnetic gearing prototype are also obtained. The induced electromotive force and electromagnetic force of the combined electrical machine have obtained consistently with the analysis by the way of numerical and analytical combined method, which proves the proposed method is correct and effective in the multiple airgaps situation.The novel electrical machine combined with a magnetic gear has a compact structure, high torque density, high power factor and the protection ability when overloaded, suits in the low speed high torque direct drive system. The smooth movement of the novel electrical machine combined with a magnetic gear has been obtained, which proves the success of the structure and the design algorithm innovation, has increased the new way for the low speed high torque electrical machine design.
A novel magnetic field modulation gearing transmits torque by magnetic force with high density and efficiency, and could be a potential substitute of a mechanical gearing if used in lustration, low temperature, high altitude environment etc. The development of high performance rare-earth permanent magnet material and its successful application in electrical machine, make it possible to provide more torque density and efficiency for a modern permanent magnet machine compared with for an induction motor.A permanent magnet electrical machine combined with a field modulation magnetic gear has been presented in this paper. The paper describes the fundamental structure of an outer rotor brushless PM motor is embedded into a novel magnetic gear. Merits of the permanent Neodymium Magnets magnet electrical machine and the novel magnetic gear are combined together for realizing a high toque low speed drive.
The research results application prospect is widespread, may be applied in the military domain (ship direct drive), the transportation (electric locomotive, electric automobile direct drive), the renewable energy development (wind power generation), the advanced manufacturing industry (machine tool direct drive) and so on.As one part of the national 863 program research project“Research on an efficient large torque direct-drive permanent magnet combined electrical machine system”(2007 AA05Z233),The text concentrates on the design of a permanent magnet electrical machine combined with a magnetic gear.This article around a permanent magnet electrical machine combined with a magnetic gear expands research, do the following tasks:1) Base upon the analytical approach of electromagnetic field as a starting point, in cylindrical coordinates find the analytical solution of Laplace’s equation in a certain annular region of the air gap. Combine the finite element method, solve overall field vector potentials in an electrical machine, and lay the foundation to calculate other physical quantities.2) Analyze deficiencies of mechanical gears and traditional magnetic gears, research magnetic field modulation magnetic gearing which is the key part of the combined electrical machine work. For the characteristic of the device with two layers of air gap, whose input rotor and output rotor turn reversely, extend numerical and analytical combined method of magnetic field calculation, and establish the corresponding program. Both in inner layer air gap and in outer layer air gap the magnetic field has many kinds of harmonic component existence, but the electromagnetic torque is nearly the sole fundamental wave ingredient, the calculation result by way of numerical and analytical combined method is consistent with the theoretical analysis.
3) After using the inner rotor’s space of the field modulation magnetic gear, considering processing, assembly and so on feasibility, has completed the electrical machinery topology innovation, i.e., designed the permanent magnet electrical machine combined with the novel magnetic gear. With the aid of the numerical and analytical combined method, has realized the magnetic field calculation under the condition that the inner rotor and the outer rotor rotate with free pace and different direction. Parameters of the induced electromotive force and the electromagnetic torque and so on of the novel motor have been calculated, and it is not difficult to catch the maximum value of cogging torque. Has designed a low speed big torque highly effective electrical machine combined with a novel magnetic gear according to certain target requests, and developed the prototype.4) The experiment has proven the union of a novel magnetic gear and a permanent magnet electrical machine in the structure innovation successfully. The electrical machine combined with a novel magnetic gear runs at a high torque density http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets with a stable movement effect. The high torque density, the high transmission efficiency and stable movement result of the magnetic gearing prototype are also obtained. The induced electromotive force and electromagnetic force of the combined electrical machine have obtained consistently with the analysis by the way of numerical and analytical combined method, which proves the proposed method is correct and effective in the multiple airgaps situation.The novel electrical machine combined with a magnetic gear has a compact structure, high torque density, high power factor and the protection ability when overloaded, suits in the low speed high torque direct drive system. The smooth movement of the novel electrical machine combined with a magnetic gear has been obtained, which proves the success of the structure and the design algorithm innovation, has increased the new way for the low speed high torque electrical machine design.
2012年1月10日星期二
Spin Reorientation Transition and the Microwave Properties of Intermetallic Compounds of Nd(Fe1-xCox)10V2
Spin Reorientation Transition and the Microwave Properties of Intermetallic Compounds of Nd(Fe1-xCox)10V2
The property of traditional high frequency magnetic materials obeys the Snoek limit, thus it is hard to improve. This study is based on principle of the rare earth-3d intermetallic compounds particles with planar magnetocrystalline anisotropy can exceed the limitation of the Snoek limit. Under the common acting of a small in plane anisotropic field and a rather large out of plane anisotropic field, which can get a higher permeability without a badly descent of resonance frequency.Using the Vanadium as a stabilizing element, and using the Cobalt to substitute the iron, The ThMn12-type rare earth-3d intermetallic compounds of Nd(Fe1-xCox)10V2 were prepared by means of vacuum arc melting, subsequent vacuum annealing, then they were ball milling for 12 hours. The influence of the Neodymium Magnets substitution of Cobalt for iron on the structure and statistic magnetic properties of these compounds is investigated by X-ray powder diffraction and magnetic measurements. The paraffin composites were prepared by mixing paraffin with compounds particles and pressing into toroidal shape, so that the relative complex permeability of the composites has been measured in the range of 0.1-10 GHz. The mechanism of relative complex permeability affected by the change of anisotropy in high frequency has been discussed. The main research contents and results are shown as follows:(1) The structure of Nd(Fe1-xCox)10V2 compounds is a single phase with tetragonal ThMn12-type structure in a range of x=0-0.5. The lattice constants and unit-cell volume decrease monotonically with increasing of Co concentration, due to Cobalt atom radius is smaller than iron.(2)
The saturation magnetization of Nd(Fe1-xCox)10V2 compounds increase from 115 emu/g (x=0) to 122 emu/g (x=0.2) at first and then decrease to 96 emu/g (x=0.5) with increasing Co concentration while the coercivity of the compounds are decreasing firstly and then keep constant, then it increased abruptly. The easy magnitization direction of the compounds also changed with the Co content from c-axial (x=0) to a-b plane(x=0.2), and return to c-axial when x=0.5.(3) The Curie temperature (Tc) of Nd(Fe1-xCox)10V2 compounds increase monotonically from 570 K (x=0) to 676 K (x=0.4) with increasing of Co concentration, but it decreased to 662 K (x=0.5)when further increase the Co content. The decrease of interatomic distances and a preferential substitution of Co for Fe in regions where there is negative exchange could account for the strengthening of exchange interaction and thus for an enhancement of Tc,(4) The M-T curves show that the temperature of spin reorientation transition (SRT) ascent quickly with increasing the Co concentration:below the room temperature, the temperature of SRT increased from 120 K (x=0) to 280 K (x=0.4); Above the room temperature, there was no SRT when x=0, while the SRT appeared after Co enter the compounds, and its temperature increased with increasing of Co content till x=0.4, when x=0.5 the temperature of SRT decreased and the transition is different with before. It is account for the Co substitution weakens the anisotropy of Fe sublattice.(5) By the Mossbauer measurement, the V atom preferes to occupy the 8i sites. When Co atom substituted the Fe atom, the Co appeared to occupy the 8f and 8j sites, this is account for the 8f and 8j sites have smaller interatomic distances and this occupation made the system with low enthalpy. The Isomer Shift (IS) of 8i and 8j sites increased obviously while that of 8f sites was almost constant. The Quadrupole Splitting (QS) value changed abruptly in 8f sites between x=0 and x=0.15, as well as in 8i sits between x=0.4 and x=0.5, which means the transition of the easy magnetization direction exists in these ranges.(6) For the paraffin composites with 35 vol.% of Nd(Fe1-xCox)10V2, both of real and imagine part of the permittivity was almost constant in our measurement frequency range, and for different x, the value did not change a lot neither, however the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets complex permeability varied with the increasing of Co concentration, the real part of permeability at low frequency was 2.2 for x=0, and then it ascend to 3.2 for x=0.2, when x=0.5, it drops to 2.3; the imagine part of permeability has no resonance peak for x=0 and x=0.5, and the eddy current loss is the main loss, but there was a resonance peak for x=0.15-0.4, and the loss was caused by nature resonance, that is in respect that the permeability has a relationship with anisotropy, when anisotropy changed, the permeability would change too.(7) The absorbing properties of the Nd(Fe1-xCox)10V2 with plane anisotropy were much better than the ones with uniaxial anisotropy.
The property of traditional high frequency magnetic materials obeys the Snoek limit, thus it is hard to improve. This study is based on principle of the rare earth-3d intermetallic compounds particles with planar magnetocrystalline anisotropy can exceed the limitation of the Snoek limit. Under the common acting of a small in plane anisotropic field and a rather large out of plane anisotropic field, which can get a higher permeability without a badly descent of resonance frequency.Using the Vanadium as a stabilizing element, and using the Cobalt to substitute the iron, The ThMn12-type rare earth-3d intermetallic compounds of Nd(Fe1-xCox)10V2 were prepared by means of vacuum arc melting, subsequent vacuum annealing, then they were ball milling for 12 hours. The influence of the Neodymium Magnets substitution of Cobalt for iron on the structure and statistic magnetic properties of these compounds is investigated by X-ray powder diffraction and magnetic measurements. The paraffin composites were prepared by mixing paraffin with compounds particles and pressing into toroidal shape, so that the relative complex permeability of the composites has been measured in the range of 0.1-10 GHz. The mechanism of relative complex permeability affected by the change of anisotropy in high frequency has been discussed. The main research contents and results are shown as follows:(1) The structure of Nd(Fe1-xCox)10V2 compounds is a single phase with tetragonal ThMn12-type structure in a range of x=0-0.5. The lattice constants and unit-cell volume decrease monotonically with increasing of Co concentration, due to Cobalt atom radius is smaller than iron.(2)
The saturation magnetization of Nd(Fe1-xCox)10V2 compounds increase from 115 emu/g (x=0) to 122 emu/g (x=0.2) at first and then decrease to 96 emu/g (x=0.5) with increasing Co concentration while the coercivity of the compounds are decreasing firstly and then keep constant, then it increased abruptly. The easy magnitization direction of the compounds also changed with the Co content from c-axial (x=0) to a-b plane(x=0.2), and return to c-axial when x=0.5.(3) The Curie temperature (Tc) of Nd(Fe1-xCox)10V2 compounds increase monotonically from 570 K (x=0) to 676 K (x=0.4) with increasing of Co concentration, but it decreased to 662 K (x=0.5)when further increase the Co content. The decrease of interatomic distances and a preferential substitution of Co for Fe in regions where there is negative exchange could account for the strengthening of exchange interaction and thus for an enhancement of Tc,(4) The M-T curves show that the temperature of spin reorientation transition (SRT) ascent quickly with increasing the Co concentration:below the room temperature, the temperature of SRT increased from 120 K (x=0) to 280 K (x=0.4); Above the room temperature, there was no SRT when x=0, while the SRT appeared after Co enter the compounds, and its temperature increased with increasing of Co content till x=0.4, when x=0.5 the temperature of SRT decreased and the transition is different with before. It is account for the Co substitution weakens the anisotropy of Fe sublattice.(5) By the Mossbauer measurement, the V atom preferes to occupy the 8i sites. When Co atom substituted the Fe atom, the Co appeared to occupy the 8f and 8j sites, this is account for the 8f and 8j sites have smaller interatomic distances and this occupation made the system with low enthalpy. The Isomer Shift (IS) of 8i and 8j sites increased obviously while that of 8f sites was almost constant. The Quadrupole Splitting (QS) value changed abruptly in 8f sites between x=0 and x=0.15, as well as in 8i sits between x=0.4 and x=0.5, which means the transition of the easy magnetization direction exists in these ranges.(6) For the paraffin composites with 35 vol.% of Nd(Fe1-xCox)10V2, both of real and imagine part of the permittivity was almost constant in our measurement frequency range, and for different x, the value did not change a lot neither, however the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets complex permeability varied with the increasing of Co concentration, the real part of permeability at low frequency was 2.2 for x=0, and then it ascend to 3.2 for x=0.2, when x=0.5, it drops to 2.3; the imagine part of permeability has no resonance peak for x=0 and x=0.5, and the eddy current loss is the main loss, but there was a resonance peak for x=0.15-0.4, and the loss was caused by nature resonance, that is in respect that the permeability has a relationship with anisotropy, when anisotropy changed, the permeability would change too.(7) The absorbing properties of the Nd(Fe1-xCox)10V2 with plane anisotropy were much better than the ones with uniaxial anisotropy.
Metallogenic Model and Prospecting Potential in Dabaoshan Molybdenum Polymetallic Ore Deposit, North Guangdong Province
Metallogenic Model and Prospecting Potential in Dabaoshan Molybdenum Polymetallic Ore Deposit, North Guangdong Province
Dabaoshan polymetallic deposit is one of well-known deposits in China. Studies of the deposit have focused on geological characteristics, mineralizing conditions and mechanism, and metallogenic models. However, there are still some key issues unresolved, such as the ages of magmatism and mineralization, the relationship between the subdacite porphyry and granodiorite porphyry and their metallogenic implication, as well as genesis of copper polymetallic ore bodies occurred in the Donggangling Formation as stratiform to stratoid, which constrain to set up the metallogenic model and prospecting model. In this study, after the extensive field work and the results of zircon U-Pb and molybdenite Re-Os geochronology, petrographic study, whole-rock geochemistry, isotopic geochemistry Neodymium Magnets and fluid inclusion, we attempt to investigate the source and petrogenesis of the porphyries, source of ore and ore-bearing fluid evolvement, the ages of magmatism and mieralization, and geodynamic setting of this deposit. Furthermore, combining with the previous data of geology, geophysical and geochemical exploration, and remote sensing, we propose the metallogenic model and prospecting direction.
The main results and conclusions are summarized as the follows:The results of zircon U-Pb dating, combining with the intrusive-contact relationship of the porphyries, show that the magma crystallization ages of the subdacite porphyry and granodiorite porphyry are about 175 Ma, but the subdacite porphyry intruded a little early. The results of molybdenite Re-Os dating suggest that the ages of porphyry-type and skarn-type Mo deposits are about 165 Ma, which are consistent with a molybdenite Re-Os model age (164.7±3 Ma) for the stratiform Cu-Pb-Zn sulfide orebody. It implied that both Mo deposit and strataform Cu-Pb-Zn deposit in the ore district could be the products of same mineralization event.The petrochemical diagrams of Rb-Y+Nb and Rb/30-Hf-Ta×3 show that the two type porphyries both formed in post-collisional lithosphere extension. In addition, the ages of magmatism and mieralization are consistent with the other Mo polymetallic deposits in the Nanling Region. Combining with previous studies, we interpret the Daobaoshan ore deposit and the porphyries as related to emplacement in an extensional setting due to post-collisional lithosphere extension.The major elements geochemical data show that the subdacite porphyry and granodiorite porphyry both are high-K calc-alkaline rock, with the character of high SiO2, enrich in K2O and Na2O, high K2O/Na2O, peraluminous and moderate fractionation. These rocks have similar major element composition and geochemical parameters, and there is a good linear relationship between SiO2 and the other oxide, indicating that they were derived from http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets the same magma source. They are enriched in large ion lithophile elements (LILE, e.g., Rb, Th, U, La, Ce, Pb) and light rare earth elements (LREE; ((La/Yb)N=6.01-0.82), depleted in Sr, Ba and heavy rare earths (HREE). Combining with the whole-rock Sr and O isotopic data, we proposed that these rocks are between I-type and S-type granites (mixed with crust and mantle components), i.e., the deep material contained mantle components resulted in the partial melting in the deep crust, simultaneity occured the crustal contamination.The 818O values range from-4.42%o to 8.05‰andδD values from-56.1‰to-50.7‰in fluid inclusions from this deposit. On the basis of this data, we proposed that the ore-forming fluids were derived from mixed source of magmatic and meteoric waters. Furthermore, most of the 834S values of the sulfide ores from the deposit are from-2.00‰to 3.00‰, which is similar to magmatic sulphur. Most of lead isotope data fall on the magmatism-lead zone, indicating that the lead source of ores was related to the Yanshanian magmatisim.
These isotope data support a genetic relationship between the Dabaoshan polymetallic deposit (including porphyry-type and skarn-type Mo deposits and strataform Cu-Pb-Zn deposit) and the two type porphyries.Fluid inclusions data show that ore-forming temperatures range from 410℃-174℃, Mineralization occurs mainly in middle to low temperature phase, molybdenum mineralization could be divided into two phases:i.e.,320℃-240℃and 220℃-170℃. Ore-forming fluids are rich in halogens and alkali, belonging to CaCl2 (MgCl2)-NaCl-KCl-H2O fluid system. Fluid salinity and density vary from 2wt%-17wt% and 0.67-0.98g/cm3, respectively. Instantaneous homogeneous pressure of fluid inclusions range from 8.4×106-169.4×106Pa, the ore-forming pressure of Cu-Pb-Zn deposit and Mo-W deposit vary from 50×106-70×106Pa and 40×106-50x106Pa, respectively. The intrusive depth of porphyries and mineralization is approximately 1.5-4 km.During the post-collisional lithosphere extension setting that may have began as early as the Early Jurassic (190-180 Ma) in the Nanling Region, the NE-trending and near SN-trending faults acted as the main structural controls for the magmatism and mineral deposits in the North Guangdong Province. The secondary faults of the NE-trending fault and the intersections of its branches were the elementary conduits for magmatism and ore-bearing fluid. The secondary faults of the main fracture, folds and the interlayer fracture zone lead the ore-bearing fluid and provided ore-forming space.These mineralizations, Mo-W mineralization and Cu-Pb-Zn mineralization in relation to the granodiorite porphyry and subdacite porphyry, consist of the porphyry-skarn-type magmatic hydrothermal ore-forming system in the Dabaoshan ore district. The Dabaoshan deposit, associated with the polymetallic Mo deposits distributed in the early to middle the Yanshannian related to the mixed crust-mantle magmatism, formed in the similar lithosphere extension setting, and constituted a region ore-forming system (magmatic hydrothermal deposits).In the early Yanshanian (about 175 Ma) the subdacite porphyry intruded along the north-northwest-trending fault, the granodiorite porphyry was subsequently following.
The post-magmatic hydrothermal, rich in ore-forming materials, intruded into the interlayer fractured zone of the Donggangling Formation and formed the stratiform to stratoid skarn-type copper-lead-zinc deposits due to the metasomatism with carbonate rock, the later ore-bearing fluid formed vien-type copper deposit. Almost at the same time, the post-magmatic hydrothermal of the granodiorite porphyry reacting with carbonate rock in the Chuandu district formed the skarn-type Mo-W deposits, that reacting with clastic strata and the subdacite porphyry formed the porphyry-type Mo deposits along the contact zone. The ore-forming stage can be divided into the follows:skarn stage, molybdenum mineralization stage, copper and lead-zinc mineralization stage, chlorite-carbonate stage, supergene oxidation stage. The time of molybdenum, copper and lead-zinc mineralization stages was consistent with each other, maybe occured overlap.The district with the following conditions is favorable to form the Mo deposit, i.e., with the subdacite porphyry and granodiorite porphyry of the early http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets Yanshanian stage, carbonate rock and clastic rock, the wall-rocks were subjected to the hydrothermal alteration, mainly including the greisenization, sericitization, skarnization and grammatite-actinolitization; Combining with multiple faults intersection and associated with secondary faults, folds, interlayer fractured zone; With pyrite, molybdenite, scheelite, wolframite; In addition, with CSAMT low resistivity anomaly, weakly positive and negative magnetic anomalies, Mo-W and other elements geochemical anomalies.In the Dabaoshan ore district, the north-east area of the Dabaoshan porphyry-type Mo deposit in the north contact zone with the subdacite porphyry is a good exploration prospect; The Daobaoshan and Chuandu granodiorite porphyries were divided by the post-mineraliton fault, the faulted space is also one of the most important next exploring direction of Mo-W, as well as the deep space of known Mo ore body.
Dabaoshan polymetallic deposit is one of well-known deposits in China. Studies of the deposit have focused on geological characteristics, mineralizing conditions and mechanism, and metallogenic models. However, there are still some key issues unresolved, such as the ages of magmatism and mineralization, the relationship between the subdacite porphyry and granodiorite porphyry and their metallogenic implication, as well as genesis of copper polymetallic ore bodies occurred in the Donggangling Formation as stratiform to stratoid, which constrain to set up the metallogenic model and prospecting model. In this study, after the extensive field work and the results of zircon U-Pb and molybdenite Re-Os geochronology, petrographic study, whole-rock geochemistry, isotopic geochemistry Neodymium Magnets and fluid inclusion, we attempt to investigate the source and petrogenesis of the porphyries, source of ore and ore-bearing fluid evolvement, the ages of magmatism and mieralization, and geodynamic setting of this deposit. Furthermore, combining with the previous data of geology, geophysical and geochemical exploration, and remote sensing, we propose the metallogenic model and prospecting direction.
The main results and conclusions are summarized as the follows:The results of zircon U-Pb dating, combining with the intrusive-contact relationship of the porphyries, show that the magma crystallization ages of the subdacite porphyry and granodiorite porphyry are about 175 Ma, but the subdacite porphyry intruded a little early. The results of molybdenite Re-Os dating suggest that the ages of porphyry-type and skarn-type Mo deposits are about 165 Ma, which are consistent with a molybdenite Re-Os model age (164.7±3 Ma) for the stratiform Cu-Pb-Zn sulfide orebody. It implied that both Mo deposit and strataform Cu-Pb-Zn deposit in the ore district could be the products of same mineralization event.The petrochemical diagrams of Rb-Y+Nb and Rb/30-Hf-Ta×3 show that the two type porphyries both formed in post-collisional lithosphere extension. In addition, the ages of magmatism and mieralization are consistent with the other Mo polymetallic deposits in the Nanling Region. Combining with previous studies, we interpret the Daobaoshan ore deposit and the porphyries as related to emplacement in an extensional setting due to post-collisional lithosphere extension.The major elements geochemical data show that the subdacite porphyry and granodiorite porphyry both are high-K calc-alkaline rock, with the character of high SiO2, enrich in K2O and Na2O, high K2O/Na2O, peraluminous and moderate fractionation. These rocks have similar major element composition and geochemical parameters, and there is a good linear relationship between SiO2 and the other oxide, indicating that they were derived from http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets the same magma source. They are enriched in large ion lithophile elements (LILE, e.g., Rb, Th, U, La, Ce, Pb) and light rare earth elements (LREE; ((La/Yb)N=6.01-0.82), depleted in Sr, Ba and heavy rare earths (HREE). Combining with the whole-rock Sr and O isotopic data, we proposed that these rocks are between I-type and S-type granites (mixed with crust and mantle components), i.e., the deep material contained mantle components resulted in the partial melting in the deep crust, simultaneity occured the crustal contamination.The 818O values range from-4.42%o to 8.05‰andδD values from-56.1‰to-50.7‰in fluid inclusions from this deposit. On the basis of this data, we proposed that the ore-forming fluids were derived from mixed source of magmatic and meteoric waters. Furthermore, most of the 834S values of the sulfide ores from the deposit are from-2.00‰to 3.00‰, which is similar to magmatic sulphur. Most of lead isotope data fall on the magmatism-lead zone, indicating that the lead source of ores was related to the Yanshanian magmatisim.
These isotope data support a genetic relationship between the Dabaoshan polymetallic deposit (including porphyry-type and skarn-type Mo deposits and strataform Cu-Pb-Zn deposit) and the two type porphyries.Fluid inclusions data show that ore-forming temperatures range from 410℃-174℃, Mineralization occurs mainly in middle to low temperature phase, molybdenum mineralization could be divided into two phases:i.e.,320℃-240℃and 220℃-170℃. Ore-forming fluids are rich in halogens and alkali, belonging to CaCl2 (MgCl2)-NaCl-KCl-H2O fluid system. Fluid salinity and density vary from 2wt%-17wt% and 0.67-0.98g/cm3, respectively. Instantaneous homogeneous pressure of fluid inclusions range from 8.4×106-169.4×106Pa, the ore-forming pressure of Cu-Pb-Zn deposit and Mo-W deposit vary from 50×106-70×106Pa and 40×106-50x106Pa, respectively. The intrusive depth of porphyries and mineralization is approximately 1.5-4 km.During the post-collisional lithosphere extension setting that may have began as early as the Early Jurassic (190-180 Ma) in the Nanling Region, the NE-trending and near SN-trending faults acted as the main structural controls for the magmatism and mineral deposits in the North Guangdong Province. The secondary faults of the NE-trending fault and the intersections of its branches were the elementary conduits for magmatism and ore-bearing fluid. The secondary faults of the main fracture, folds and the interlayer fracture zone lead the ore-bearing fluid and provided ore-forming space.These mineralizations, Mo-W mineralization and Cu-Pb-Zn mineralization in relation to the granodiorite porphyry and subdacite porphyry, consist of the porphyry-skarn-type magmatic hydrothermal ore-forming system in the Dabaoshan ore district. The Dabaoshan deposit, associated with the polymetallic Mo deposits distributed in the early to middle the Yanshannian related to the mixed crust-mantle magmatism, formed in the similar lithosphere extension setting, and constituted a region ore-forming system (magmatic hydrothermal deposits).In the early Yanshanian (about 175 Ma) the subdacite porphyry intruded along the north-northwest-trending fault, the granodiorite porphyry was subsequently following.
The post-magmatic hydrothermal, rich in ore-forming materials, intruded into the interlayer fractured zone of the Donggangling Formation and formed the stratiform to stratoid skarn-type copper-lead-zinc deposits due to the metasomatism with carbonate rock, the later ore-bearing fluid formed vien-type copper deposit. Almost at the same time, the post-magmatic hydrothermal of the granodiorite porphyry reacting with carbonate rock in the Chuandu district formed the skarn-type Mo-W deposits, that reacting with clastic strata and the subdacite porphyry formed the porphyry-type Mo deposits along the contact zone. The ore-forming stage can be divided into the follows:skarn stage, molybdenum mineralization stage, copper and lead-zinc mineralization stage, chlorite-carbonate stage, supergene oxidation stage. The time of molybdenum, copper and lead-zinc mineralization stages was consistent with each other, maybe occured overlap.The district with the following conditions is favorable to form the Mo deposit, i.e., with the subdacite porphyry and granodiorite porphyry of the early http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets Yanshanian stage, carbonate rock and clastic rock, the wall-rocks were subjected to the hydrothermal alteration, mainly including the greisenization, sericitization, skarnization and grammatite-actinolitization; Combining with multiple faults intersection and associated with secondary faults, folds, interlayer fractured zone; With pyrite, molybdenite, scheelite, wolframite; In addition, with CSAMT low resistivity anomaly, weakly positive and negative magnetic anomalies, Mo-W and other elements geochemical anomalies.In the Dabaoshan ore district, the north-east area of the Dabaoshan porphyry-type Mo deposit in the north contact zone with the subdacite porphyry is a good exploration prospect; The Daobaoshan and Chuandu granodiorite porphyries were divided by the post-mineraliton fault, the faulted space is also one of the most important next exploring direction of Mo-W, as well as the deep space of known Mo ore body.
Sedimentary Response to the Late Caledonian-Early Hercynian Orogenesis, the North Qilian Orogen
Sedimentary Response to the Late Caledonian-Early Hercynian Orogenesis, the North Qilian Orogen
Orogen and basin are the best basic structural types on the surface of Earth. The Orogenic Sedimentology is a subject that organically contact with them. With the modern geological theory, the Orogen Sedimentology employs the regional stratigraphy, sedimentology, tectonics, geochemistry, and geophysics to reveal the formation and distribution of basin, composition and evolvement, to reconstruct the paleogeography, the ancient ocean, the ancient structure and the lithosphere dynamics. Sedimentary response to orogenesis, also named to basin-range interaction, is an important content in the Orogenic Sedimentary and Sedimentary Geology. Provenance of synorogenic basin and its variation with the time are important ways and means by which to reconstruct the orogenesis and evolvement of basin.The North Qilian Orogenic Belt (NQOB) is located in the northeastern margin Neodymium Magnets of the Tibetan Plateau. It succeeded the breakup of Rodinian Supercontinent, experiencing an evolution of rift in the early Cambrian and mature ocean in the late Cambrian-Ordovician, the active continent margin in the middle-late Ordovician, collision in Silurian-Devonian on the south margin of the North China Plate. The process of orogenesis and the attribute of synorogenic basin are still debated and the details of transfer of synorogenic basin is retain faintly. This paper studied the provenance of the terrigenous detrital rocks in Ordovician-Devonian by composition of fragment, sedimentary geochemistry and chronology of detrital zircon with the geological investigation in the field, which shed light on the several key scientific questions about tectonic evolution of orogen and synorogenic basin.Detrital zircons from the middle-late Ordovician were dated and show a wide age range from Archean to the early Paleozoic with prominent peak at around 2.5 Ga,1.6 Ga,1.0 Ga, and 0.47Ga. Combined the regional magmatic events, Archean and the early Proterozoic detritus mainly derived from the North China Craton (NC) to the north, whereas the Central Qilian Block (CQ) to the south likely provided the late Proterozoic grains.
The early Paleozoic ages are in consistent with the time of magmatic arc related to subduction of oceanic crust. Precambrian grains were restricted to the upper of section, with Paleozoic grains descending from bottom to upper of section, which reflect the initial collision between the CQ and NC. The two youngest zircons from the bottom of section suggest that the time of initial collision is located in the 467Ma-450Ma.Composition of detrital rocks in Silurian shows quartz to ascend from Sunan to Shihuigou, to Shuiquan and from lower to upper in the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets section. Along the trending of orogen, rock fragments gradually descend from Sunan to Shihuigou, to Shuiquan, however, metamorphic rock fragments display a reverse variation. And metamorphic rock fragments in the Shuiquan area is evidently more than that in the Sunan and Shihuigou areas. In Shuiquan section, metamorphic rock fragments gradually descend from lower to upper, whereas those in the Sunan and Shihuigou sections ascend from lower to upper. The volcanic and sedimentary rocks fragments exist largely in the Sunan and Shuiquan areas and absent in the Shuiquan area. The volcanic rocks fragments gradually descend and the sedimentary rocks fragments ascend from lower to upper in Sunan and Shuiquan sections. In all studied sections, the content of feldspar in the eastern part of orogen is consistent with that in the western part of orogen.Geochemical analyses for detrital rocks in Silurian show:①major elements in all samples usually lower than those of PAAS, indicating the low mature, except for mudstones in the Shuiquan area. Mudstones from Shuiquan area occupy the higher femic, k-feldspar and clay minerals contents, and lower SiO2 content, relative to those of sandstones. Samples from Sunan area show the descending SiO2 content and ascending femic composition from lower to upper of section, but the contents of K-feldspar and plagioclase are equivalent in the lower and upper of section. CaO2 contents of most samples linearly relative to CO2 contents of them, which suggest that CaO2 are contained mainly in the carbonate.②All samples from Sunan area and sandstones from Shuiquan area display the lower trace elements contents relative to PAAS in the Upper crust-normalized spider diagrams, whereas mudstones from Shuiquan area show the higher trace elements contents than those of PAAS. In the upper crust-normalized spider diagrams, all samples are depleted in Nb, Ta, and Sr elements. Samples from Sunan area and sandstones from Shuiquan are depleted in Rb, whereas mudstones from Shuiquan area are closed to the upper crust in Rb. The contents of Ni, Cr elements are enrichment with all samples from Sunan area and mudstones from Shuiquan area and are depleted with sandstones from Shuiquan area.
All of the samples display a right-inclined REE pattern after Chondrite-normalized. Rare earth elements (REE) of samples from the Hanxia Formation in Sunan area are similar to those of PAAS, with the lower contents of the Lujiaogou, Angzanggou, Qunnaogou Formation relative to PAAS. REE of samples from Shuiquan area show similar characters to maior elements and trace elements. REE of sandstones is lower than that of PAAS and REE of mudstones is higher than that of PAAS. All samples exhibit relatively strong negative Eu anomalies. These geochemical characteristics suggest the input of the felsic and mafic clast with minor granitic rocks into the eastern and wastern area. However, source of sediments in the eastern part underwent the weak chemical weathering and sedimentary recycle. Evidences combining tectonic discriminations and detrital zircon chronology suggest that sediments in the Sunan area were derived mainly from the metamorphic basement of CQ (1.6Ga,1.0Ga), the North Qilian Continental Arc (NQA) (0.45Ga), subducted complex (SC) (0.5-0.6Ga) and NC (2.5Ga), whereas sediments in Shuiquan area predominately came from the metamorphic basement of CQ and NC without the NQA. Combined the descending volcanic rocks fragments from lower to upper, alteration of provenance indicates that NQA was buried under the sediments from the two continents after the initial collision.The Middle-Lower Devonian Laojunshan Formation is a suite of molasse formed during the rapid uplift of the North Qilian Orogenic Belt (NQOB).41 sandstones have be sampled from the Sunan and Minle sections in the western sector and the Gulang and Jingyuan sections in the eastern sector of the NQOB belt. Geochemical analyses of those samples indicated:①the MgO+Fe2O3T and Al2O3/SiO2 values are higher, and K20/Na2O ratios are lower in the western sector than those in the eastern sector.②All of them are depleted in Nb and Ta elements. The samples from the western sector are depleted in Rb element and enriched with Sc, Co, Ni, V, and Cr elements in the Upper Crust-normalized patterns. However, those from the eastern sector are depleted in Sr without enrichments of Sc, Co, Ni, V, and Cr.③All of the samples display a right-inclined REE pattern after Chondrite-normalized. But LaN/YbN and Eu/Eu* ratios of the samples from the western sector are lower than those of the samples from the eastern sector. These geochemical characteristics suggest the prominent input of mafic clast with minor granitic rocks into the Sunan area, felsic clast into the Gulang and Jingyuan area, both mafic and felsic clast into the Minle area. The angular shapes of gravels imply that these ill-sorted sediments were deposited near their sources without recycling.
Geochemical features above also demonstrated that no major chemical weathering occurred for the western provenance, but deposits in the eastern sector resulted from low or middle degree chemical weathering. Evidences combining tectonic discriminations and detrital zircon chronology revealed that sediments in the Sunan area were derived mainly from NQA (0.5-0.4Ga) and SC (0.5-0.6Ga), while sediments in the Minle, Gulang, and Jingyuan areas were derived not only from NQA (0.5-0.4Ga) and SC (0.5-0.6Ga) but also from the basement of the metamorphic basement of CQ (1.6Ga、1.OGa) and NC (2.5Ga).The Upper Devonian Shaliushui Formation had recorded the end of the orogeny. Samples from the studied section located in the Shaliushui, Jingyuan County, contain major quartz and minor fragments and feldspar. All samples are depleted in Nb, Ta, and Sr elements and negative Eu anomalies. Geochemical data show that source underwent the middle chemical weathering and sediments did not undergo sedimentary recycle. Sediments were derived mainly from the felsic and mafic rocks, with minor granitic rocks. The tectonic discriminations and detrital zircon http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets chronology revealed that sediments in the Upper Devonian were derived from NQA (0.5-0.4Ga) exhumed, and the metamorphic basement of CQ (1.6Ga、1.0Ga), SC (0.5-0.6Ga) and NC(2.5Ga) engulfed into orogen.Provenance and its alteration with the time can draw the following conclusion:1. The Late Ordovician detrital zircon chronology suggest that sediments in the eastern part of NQOB maily derived from the North Qilian Arc, no from the continental block at the two side of basin. However, until the late of Late Ordovician, a large of sediments from the two continental block, the Central Qilian Block to the south and the North China Plate to the north, were filled in the basin and buried the North Qilian Arc, which resulted into the decreasing sediments from the North Qilian Arc and the increasing sedioments from the two continental block with the time going. Integrated the outcrop of the Lujiaogou Formation, the Tianzhu Formation should be as sedimentary record of the initial collision.2. The composition, geochemistry and chronology of detrital rocks in Silurian show that provenance of eastern basin maily came from the Central Qilian Block and North China Plate and sediments underwent the chemical weathering and sedimentary recycle, whereas sediments without the chemical weathering and sedimentary recycle in the western basin mainly derived from the North Qilian Arc, the Central Qilian Block and North China Plate.3. The composition, geochemistry and chronology of detrital rocks in Devonian show that sediments from the Laojunshan Fromation in the western basin mainly derived from the North Qilian Arc without the chemical weathering, with no sediments from the continental block, and sediments did not undergo the sedimentary recycle.
However, sediments deposited in the eastern part of basin mainly came from the North Qilian Arc, the Central Qilian Block and North China Plate, with the chemical weathering and sedimentary recycle. Provenance of the Upper Dovonian Shaliushui Formation inherited that of the Laojunshan Formation in the eastern basin. Sediments mainly were supplied by the North Qilian Arc, the Central Qilian Block and North China Plate engulfed into the orogenic belt.4. The detrital zircons with U-Pb ages of 8-10 Ga occur in the Ordovician-Devonian sediments, which indicated that the source of them, the Central Qilian block, similar to the Yangtze Plate and dissimilar to the North China Plate on the basis of sedimentology.5. The initial collision between the Central Qilian block and North China Plate happened in the Middle-Late Ordovician (467-450 Ma) at the eastern part of orogen, Wuweu area. This event resulted in the collisional conglomerate (the Tianzhu and Gulang Formation) and the unconformity between the middle and late Ordovician, named the Gulang Movement. The sequent collision occurred at the Sunan area in the Early Silurian and formed the Lujiaogou Formation conglomerate. Thus collision between the Central Qilian Block and North China Plate show that the orogeny of NQOB was diachronous in the trending direction from east to west.6. The provenance of the lower and middle Devonian Laojunshan Formation and the distributions of Silurian-Devonian jointly suggest that the orogeny of NQOB was diachronous in the trending direction and the eastern sector had stronger tectonic intensity compared to the western sector, which resulted into the Late Devonian collapse in the eastern part of orogen7. The synorogenic basin in the North Qilian-Hexi Corridor belt had transferred from the Early-middle Ordovician retroarc basin to the Late Ordovician remnant retroarc basin, to Silurian-Devonian foreland basin and the remnant retroarc basin and foreland basin indeed coexisted in the Late Ordovician-Early Silurian.
Orogen and basin are the best basic structural types on the surface of Earth. The Orogenic Sedimentology is a subject that organically contact with them. With the modern geological theory, the Orogen Sedimentology employs the regional stratigraphy, sedimentology, tectonics, geochemistry, and geophysics to reveal the formation and distribution of basin, composition and evolvement, to reconstruct the paleogeography, the ancient ocean, the ancient structure and the lithosphere dynamics. Sedimentary response to orogenesis, also named to basin-range interaction, is an important content in the Orogenic Sedimentary and Sedimentary Geology. Provenance of synorogenic basin and its variation with the time are important ways and means by which to reconstruct the orogenesis and evolvement of basin.The North Qilian Orogenic Belt (NQOB) is located in the northeastern margin Neodymium Magnets of the Tibetan Plateau. It succeeded the breakup of Rodinian Supercontinent, experiencing an evolution of rift in the early Cambrian and mature ocean in the late Cambrian-Ordovician, the active continent margin in the middle-late Ordovician, collision in Silurian-Devonian on the south margin of the North China Plate. The process of orogenesis and the attribute of synorogenic basin are still debated and the details of transfer of synorogenic basin is retain faintly. This paper studied the provenance of the terrigenous detrital rocks in Ordovician-Devonian by composition of fragment, sedimentary geochemistry and chronology of detrital zircon with the geological investigation in the field, which shed light on the several key scientific questions about tectonic evolution of orogen and synorogenic basin.Detrital zircons from the middle-late Ordovician were dated and show a wide age range from Archean to the early Paleozoic with prominent peak at around 2.5 Ga,1.6 Ga,1.0 Ga, and 0.47Ga. Combined the regional magmatic events, Archean and the early Proterozoic detritus mainly derived from the North China Craton (NC) to the north, whereas the Central Qilian Block (CQ) to the south likely provided the late Proterozoic grains.
The early Paleozoic ages are in consistent with the time of magmatic arc related to subduction of oceanic crust. Precambrian grains were restricted to the upper of section, with Paleozoic grains descending from bottom to upper of section, which reflect the initial collision between the CQ and NC. The two youngest zircons from the bottom of section suggest that the time of initial collision is located in the 467Ma-450Ma.Composition of detrital rocks in Silurian shows quartz to ascend from Sunan to Shihuigou, to Shuiquan and from lower to upper in the http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets section. Along the trending of orogen, rock fragments gradually descend from Sunan to Shihuigou, to Shuiquan, however, metamorphic rock fragments display a reverse variation. And metamorphic rock fragments in the Shuiquan area is evidently more than that in the Sunan and Shihuigou areas. In Shuiquan section, metamorphic rock fragments gradually descend from lower to upper, whereas those in the Sunan and Shihuigou sections ascend from lower to upper. The volcanic and sedimentary rocks fragments exist largely in the Sunan and Shuiquan areas and absent in the Shuiquan area. The volcanic rocks fragments gradually descend and the sedimentary rocks fragments ascend from lower to upper in Sunan and Shuiquan sections. In all studied sections, the content of feldspar in the eastern part of orogen is consistent with that in the western part of orogen.Geochemical analyses for detrital rocks in Silurian show:①major elements in all samples usually lower than those of PAAS, indicating the low mature, except for mudstones in the Shuiquan area. Mudstones from Shuiquan area occupy the higher femic, k-feldspar and clay minerals contents, and lower SiO2 content, relative to those of sandstones. Samples from Sunan area show the descending SiO2 content and ascending femic composition from lower to upper of section, but the contents of K-feldspar and plagioclase are equivalent in the lower and upper of section. CaO2 contents of most samples linearly relative to CO2 contents of them, which suggest that CaO2 are contained mainly in the carbonate.②All samples from Sunan area and sandstones from Shuiquan area display the lower trace elements contents relative to PAAS in the Upper crust-normalized spider diagrams, whereas mudstones from Shuiquan area show the higher trace elements contents than those of PAAS. In the upper crust-normalized spider diagrams, all samples are depleted in Nb, Ta, and Sr elements. Samples from Sunan area and sandstones from Shuiquan are depleted in Rb, whereas mudstones from Shuiquan area are closed to the upper crust in Rb. The contents of Ni, Cr elements are enrichment with all samples from Sunan area and mudstones from Shuiquan area and are depleted with sandstones from Shuiquan area.
All of the samples display a right-inclined REE pattern after Chondrite-normalized. Rare earth elements (REE) of samples from the Hanxia Formation in Sunan area are similar to those of PAAS, with the lower contents of the Lujiaogou, Angzanggou, Qunnaogou Formation relative to PAAS. REE of samples from Shuiquan area show similar characters to maior elements and trace elements. REE of sandstones is lower than that of PAAS and REE of mudstones is higher than that of PAAS. All samples exhibit relatively strong negative Eu anomalies. These geochemical characteristics suggest the input of the felsic and mafic clast with minor granitic rocks into the eastern and wastern area. However, source of sediments in the eastern part underwent the weak chemical weathering and sedimentary recycle. Evidences combining tectonic discriminations and detrital zircon chronology suggest that sediments in the Sunan area were derived mainly from the metamorphic basement of CQ (1.6Ga,1.0Ga), the North Qilian Continental Arc (NQA) (0.45Ga), subducted complex (SC) (0.5-0.6Ga) and NC (2.5Ga), whereas sediments in Shuiquan area predominately came from the metamorphic basement of CQ and NC without the NQA. Combined the descending volcanic rocks fragments from lower to upper, alteration of provenance indicates that NQA was buried under the sediments from the two continents after the initial collision.The Middle-Lower Devonian Laojunshan Formation is a suite of molasse formed during the rapid uplift of the North Qilian Orogenic Belt (NQOB).41 sandstones have be sampled from the Sunan and Minle sections in the western sector and the Gulang and Jingyuan sections in the eastern sector of the NQOB belt. Geochemical analyses of those samples indicated:①the MgO+Fe2O3T and Al2O3/SiO2 values are higher, and K20/Na2O ratios are lower in the western sector than those in the eastern sector.②All of them are depleted in Nb and Ta elements. The samples from the western sector are depleted in Rb element and enriched with Sc, Co, Ni, V, and Cr elements in the Upper Crust-normalized patterns. However, those from the eastern sector are depleted in Sr without enrichments of Sc, Co, Ni, V, and Cr.③All of the samples display a right-inclined REE pattern after Chondrite-normalized. But LaN/YbN and Eu/Eu* ratios of the samples from the western sector are lower than those of the samples from the eastern sector. These geochemical characteristics suggest the prominent input of mafic clast with minor granitic rocks into the Sunan area, felsic clast into the Gulang and Jingyuan area, both mafic and felsic clast into the Minle area. The angular shapes of gravels imply that these ill-sorted sediments were deposited near their sources without recycling.
Geochemical features above also demonstrated that no major chemical weathering occurred for the western provenance, but deposits in the eastern sector resulted from low or middle degree chemical weathering. Evidences combining tectonic discriminations and detrital zircon chronology revealed that sediments in the Sunan area were derived mainly from NQA (0.5-0.4Ga) and SC (0.5-0.6Ga), while sediments in the Minle, Gulang, and Jingyuan areas were derived not only from NQA (0.5-0.4Ga) and SC (0.5-0.6Ga) but also from the basement of the metamorphic basement of CQ (1.6Ga、1.OGa) and NC (2.5Ga).The Upper Devonian Shaliushui Formation had recorded the end of the orogeny. Samples from the studied section located in the Shaliushui, Jingyuan County, contain major quartz and minor fragments and feldspar. All samples are depleted in Nb, Ta, and Sr elements and negative Eu anomalies. Geochemical data show that source underwent the middle chemical weathering and sediments did not undergo sedimentary recycle. Sediments were derived mainly from the felsic and mafic rocks, with minor granitic rocks. The tectonic discriminations and detrital zircon http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets chronology revealed that sediments in the Upper Devonian were derived from NQA (0.5-0.4Ga) exhumed, and the metamorphic basement of CQ (1.6Ga、1.0Ga), SC (0.5-0.6Ga) and NC(2.5Ga) engulfed into orogen.Provenance and its alteration with the time can draw the following conclusion:1. The Late Ordovician detrital zircon chronology suggest that sediments in the eastern part of NQOB maily derived from the North Qilian Arc, no from the continental block at the two side of basin. However, until the late of Late Ordovician, a large of sediments from the two continental block, the Central Qilian Block to the south and the North China Plate to the north, were filled in the basin and buried the North Qilian Arc, which resulted into the decreasing sediments from the North Qilian Arc and the increasing sedioments from the two continental block with the time going. Integrated the outcrop of the Lujiaogou Formation, the Tianzhu Formation should be as sedimentary record of the initial collision.2. The composition, geochemistry and chronology of detrital rocks in Silurian show that provenance of eastern basin maily came from the Central Qilian Block and North China Plate and sediments underwent the chemical weathering and sedimentary recycle, whereas sediments without the chemical weathering and sedimentary recycle in the western basin mainly derived from the North Qilian Arc, the Central Qilian Block and North China Plate.3. The composition, geochemistry and chronology of detrital rocks in Devonian show that sediments from the Laojunshan Fromation in the western basin mainly derived from the North Qilian Arc without the chemical weathering, with no sediments from the continental block, and sediments did not undergo the sedimentary recycle.
However, sediments deposited in the eastern part of basin mainly came from the North Qilian Arc, the Central Qilian Block and North China Plate, with the chemical weathering and sedimentary recycle. Provenance of the Upper Dovonian Shaliushui Formation inherited that of the Laojunshan Formation in the eastern basin. Sediments mainly were supplied by the North Qilian Arc, the Central Qilian Block and North China Plate engulfed into the orogenic belt.4. The detrital zircons with U-Pb ages of 8-10 Ga occur in the Ordovician-Devonian sediments, which indicated that the source of them, the Central Qilian block, similar to the Yangtze Plate and dissimilar to the North China Plate on the basis of sedimentology.5. The initial collision between the Central Qilian block and North China Plate happened in the Middle-Late Ordovician (467-450 Ma) at the eastern part of orogen, Wuweu area. This event resulted in the collisional conglomerate (the Tianzhu and Gulang Formation) and the unconformity between the middle and late Ordovician, named the Gulang Movement. The sequent collision occurred at the Sunan area in the Early Silurian and formed the Lujiaogou Formation conglomerate. Thus collision between the Central Qilian Block and North China Plate show that the orogeny of NQOB was diachronous in the trending direction from east to west.6. The provenance of the lower and middle Devonian Laojunshan Formation and the distributions of Silurian-Devonian jointly suggest that the orogeny of NQOB was diachronous in the trending direction and the eastern sector had stronger tectonic intensity compared to the western sector, which resulted into the Late Devonian collapse in the eastern part of orogen7. The synorogenic basin in the North Qilian-Hexi Corridor belt had transferred from the Early-middle Ordovician retroarc basin to the Late Ordovician remnant retroarc basin, to Silurian-Devonian foreland basin and the remnant retroarc basin and foreland basin indeed coexisted in the Late Ordovician-Early Silurian.
2012年1月5日星期四
Research on the Digital Servo System for the Permanent Magnet Synchronous Motor
Research on the Digital Servo System for the Permanent Magnet Synchronous Motor
High performance AC servo systems, widely used in various areas, are demanded with the development of modern industrialization. AC servo systems have advantages over DC servo systems, so it is very important to develop high performance and high reliability AC servo control systems.In this paper, the control method of the permanent magnet rare earth magnets synchronous motor(PMSM) and its mathematic model are fully studied. The working principles of PMSM and close-loop control methods of PMSM current、speed and position are detailly discussed based on the PMSM mathematical models in the different reference frames. Then the position servo system is simulated by MATLAB/SIMULINK.
The control method is proved correct by the simulation result. Moreover the thesis presents a high-frequency signal injection method to observe rotor position based on Permanent Magnet Synchronous Motor models. The simulation results show it is adjusting and effective to estimate rotor position.It’s proved successful on PMSM’s servo control http://www.chinamagnets.biz/ based on the Digital Signal Processor(DSP) chip TMS320F2812, including current、speed and position control. The experimental results prove that this servo system has very wide range of regulating speed and has good dynamic and static behaviors .Moreover some functions of servo system are accomplished. So, the servo system can meet the demand of high control performance.
High performance AC servo systems, widely used in various areas, are demanded with the development of modern industrialization. AC servo systems have advantages over DC servo systems, so it is very important to develop high performance and high reliability AC servo control systems.In this paper, the control method of the permanent magnet rare earth magnets synchronous motor(PMSM) and its mathematic model are fully studied. The working principles of PMSM and close-loop control methods of PMSM current、speed and position are detailly discussed based on the PMSM mathematical models in the different reference frames. Then the position servo system is simulated by MATLAB/SIMULINK.
The control method is proved correct by the simulation result. Moreover the thesis presents a high-frequency signal injection method to observe rotor position based on Permanent Magnet Synchronous Motor models. The simulation results show it is adjusting and effective to estimate rotor position.It’s proved successful on PMSM’s servo control http://www.chinamagnets.biz/ based on the Digital Signal Processor(DSP) chip TMS320F2812, including current、speed and position control. The experimental results prove that this servo system has very wide range of regulating speed and has good dynamic and static behaviors .Moreover some functions of servo system are accomplished. So, the servo system can meet the demand of high control performance.
2012年1月3日星期二
新疆库鲁克塔格地区新元古代—早寒武世火山岩地质—地球化学特征及其构造意义
题名:新疆库鲁克塔格地区新元古代—早寒武世火山岩地质—地球化学特征及其构造意义
作者:展新忠
学位授予单位:新疆大学
关键词:库鲁克塔格;;新元古代-早寒武世;;火山岩;;岩石学;;地球化学;;构造演化;;Rodinia超大陆
摘要:
本文着重从岩石学、地球化学角度对库鲁克塔格地区新元古代-早寒武世火山岩进行系统的讨论，同时对火山岩的形成环境、成因、源区性质及形成时代进行了探讨和全面认识。借助地球化学数据的分析和对比研究为该区前寒武纪地质演化、Rodinia超大陆的裂解过程研究提供重要依据。
通过对库鲁克塔格地区新元古代-早寒武世火山岩的岩石学、岩石地球化学、稀土元素和微量元素地球化学特征的系统研究，并结合区域地质资料，取得了以下结论：
本区新元古代-早寒武世火山岩均形Neodymium Magnets成于伸展的大地构造背景下，可能为大陆裂谷环境；其成因与地幔柱的上涌有关，源区具有石榴子石二辉橄榄岩稳定区、石榴子石二辉橄榄岩向尖晶石二辉橄榄岩稳定区过度的性质。其形成时，大陆地壳开始减薄，处于拉张裂解状态，正是Rodinia超级古大陆裂解作用在本区的表现，是本区Rodinia超级古大陆裂解事件的岩石记录，是塔http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets里木运动的重要佐证，它们可能是Rodinia超级古大陆裂解作用的深部地球动力学的库鲁克塔格地区的地表响应，是古亚洲洋开启的前兆标志。因此，对本区新元古代火山岩进行研究，对揭示本区古陆块构造演化具有重要的地质意义。
学位年度:2010
作者:展新忠
学位授予单位:新疆大学
关键词:库鲁克塔格;;新元古代-早寒武世;;火山岩;;岩石学;;地球化学;;构造演化;;Rodinia超大陆
摘要:
本文着重从岩石学、地球化学角度对库鲁克塔格地区新元古代-早寒武世火山岩进行系统的讨论，同时对火山岩的形成环境、成因、源区性质及形成时代进行了探讨和全面认识。借助地球化学数据的分析和对比研究为该区前寒武纪地质演化、Rodinia超大陆的裂解过程研究提供重要依据。
通过对库鲁克塔格地区新元古代-早寒武世火山岩的岩石学、岩石地球化学、稀土元素和微量元素地球化学特征的系统研究，并结合区域地质资料，取得了以下结论：
本区新元古代-早寒武世火山岩均形Neodymium Magnets成于伸展的大地构造背景下，可能为大陆裂谷环境；其成因与地幔柱的上涌有关，源区具有石榴子石二辉橄榄岩稳定区、石榴子石二辉橄榄岩向尖晶石二辉橄榄岩稳定区过度的性质。其形成时，大陆地壳开始减薄，处于拉张裂解状态，正是Rodinia超级古大陆裂解作用在本区的表现，是本区Rodinia超级古大陆裂解事件的岩石记录，是塔http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets里木运动的重要佐证，它们可能是Rodinia超级古大陆裂解作用的深部地球动力学的库鲁克塔格地区的地表响应，是古亚洲洋开启的前兆标志。因此，对本区新元古代火山岩进行研究，对揭示本区古陆块构造演化具有重要的地质意义。
学位年度:2010
向家坝水电站施工期通航问题研究
题名:向家坝水电站施工期通航问题研究
作者:金瑞
学位授予单位:重庆交通大学
关键词:通航条件;;施工导流;;翻坝转运;;转运码头
摘要:
金沙江腹地矿产资源丰富,铁矿石和稀土储量位居全国前列,磷矿资源亦较丰富,沿线的攀枝花市是全国著名的钢铁工业基地,内河航道在腹地资源开发和经济发展过程中发挥重要作用。向家坝水电站是金沙江下游河段规划的最末一个梯级,电站河段河床地势复杂,滩险众多,水面比降大,河道宽窄相间,电站施工导流期未设置临时船闸,电站下段又受横江河口的顶托,该航段的滩险情况、水流条件及泥沙冲於Neodymium Magnets变化情况极其复杂。为保证客货运输畅通,保证电站建设顺利进行,在整个向家坝水电站可行性研究阶段,必须开展电站施工期通航研究工作。
本文主要从向家坝水电站施工期导流及通航方式、一期施工导流期对航道的影响及通航条件、二期施工断航期翻坝转运条件、库区转运码头的通航条件等方面,采用二维水流数学模型的计算方式,模拟并研http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets究了各个阶段的通航条件,为确保电站建设期间的航运畅通及航运安全提供技术支持。
从已经完成并投入使用的工程来看,该项目的研究已经取得了良好的效果,成功地解决了施工一期碍航问题,翻坝转运运行良好,航道畅通,没有发生一起海损事故,产生了明显的社会效益和经济效益。本文的研究成果可供类似的电站施工期通航问题研究参照。
学位年度:2010
作者:金瑞
学位授予单位:重庆交通大学
关键词:通航条件;;施工导流;;翻坝转运;;转运码头
摘要:
金沙江腹地矿产资源丰富,铁矿石和稀土储量位居全国前列,磷矿资源亦较丰富,沿线的攀枝花市是全国著名的钢铁工业基地,内河航道在腹地资源开发和经济发展过程中发挥重要作用。向家坝水电站是金沙江下游河段规划的最末一个梯级,电站河段河床地势复杂,滩险众多,水面比降大,河道宽窄相间,电站施工导流期未设置临时船闸,电站下段又受横江河口的顶托,该航段的滩险情况、水流条件及泥沙冲於Neodymium Magnets变化情况极其复杂。为保证客货运输畅通,保证电站建设顺利进行,在整个向家坝水电站可行性研究阶段,必须开展电站施工期通航研究工作。
本文主要从向家坝水电站施工期导流及通航方式、一期施工导流期对航道的影响及通航条件、二期施工断航期翻坝转运条件、库区转运码头的通航条件等方面,采用二维水流数学模型的计算方式,模拟并研http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets究了各个阶段的通航条件,为确保电站建设期间的航运畅通及航运安全提供技术支持。
从已经完成并投入使用的工程来看,该项目的研究已经取得了良好的效果,成功地解决了施工一期碍航问题,翻坝转运运行良好,航道畅通,没有发生一起海损事故,产生了明显的社会效益和经济效益。本文的研究成果可供类似的电站施工期通航问题研究参照。
学位年度:2010
铁掺杂氧化锆固体电解质结构及性能研究
题名:铁掺杂氧化锆固体电解质结构及性能研究
作者:胡涛
学位授予单位:武汉理工大学
关键词:掺杂氧化锆;;固体电解质;;电导率;;电子电导
摘要:
氧化锆固体电解质具有高的离子电导率、良好的结构稳定性,成为固体燃料电池及冶金定氧传感器用固体电解质的首选材料。然而纯氧化锆固体电解质的晶型随着温度的变化是不稳定的,必须向氧化锆固体电解质中添加各种稳定剂。在冶金生产和高温冶金物理化学研究中应用最广的固体电解质就是以氧化锆为基体,掺杂一定量的二价或者三价氧化物(如CaO、MgO、Y2O3和其他稀土氧化物)烧结制成的代位固溶体高温固体电解质。
本文以MgO和Fe2O3共同作为稳定Magnetic lifter剂掺入氧化锆中,采用固相反应法制备了铁镁共掺杂氧化锆固体电解质。通过XRD、SEM及交流阻抗分析等测试手段和技术对制备样品进行了结构表征和性能测试,重点讨论了氧化铁的掺入对氧化镁稳定氧化锆固体电解质的相组成、微观结构及电性能的影响规律。
XRD测试结果表明氧化铁单独掺杂氧化锆中并不起稳定剂作用,但是与MgO共掺杂后对MgO稳定作用起催化剂作用,促进了其在较少掺入量、较低温度下产生较多的立方相。因此,为了获得预期相组成固体电解质,必须综合协调好氧化铁、氧化镁掺入量与烧结温度的关系。通过SEM测试结果发现一个有趣的现象,掺杂氧化铁的样品发现了特殊的网格状晶形,并且网格状晶形的含量与氧化铁的掺入量具有明显依赖关系。同时氧化铁在适宜的掺入量下能够促进氧化锆固体电解质体系的致密性。
利用交流阻抗谱技术研究了不同组分、不同烧结温度下系列样品的导电性,系统深入的探讨了氧化铁对固体电解质的http://www.999magnet.com/products/131-magnetic-lifter电导特性的影响。研究结果表明,氧化铁的掺入改变了体系的电导特性,增加了体系的电子电导比例,并考察了体系的电导率、离子电导活化能与氧化铁掺入量的关系。
用注射成型技术制备了MgO部分稳定氧化锆固体电解质锆管,并组装成套钢液快速定氧传感器,并在鞍钢和华西钢厂进行了现场定氧测试。
学位年度:2010
作者:胡涛
学位授予单位:武汉理工大学
关键词:掺杂氧化锆;;固体电解质;;电导率;;电子电导
摘要:
氧化锆固体电解质具有高的离子电导率、良好的结构稳定性,成为固体燃料电池及冶金定氧传感器用固体电解质的首选材料。然而纯氧化锆固体电解质的晶型随着温度的变化是不稳定的,必须向氧化锆固体电解质中添加各种稳定剂。在冶金生产和高温冶金物理化学研究中应用最广的固体电解质就是以氧化锆为基体,掺杂一定量的二价或者三价氧化物(如CaO、MgO、Y2O3和其他稀土氧化物)烧结制成的代位固溶体高温固体电解质。
本文以MgO和Fe2O3共同作为稳定Magnetic lifter剂掺入氧化锆中,采用固相反应法制备了铁镁共掺杂氧化锆固体电解质。通过XRD、SEM及交流阻抗分析等测试手段和技术对制备样品进行了结构表征和性能测试,重点讨论了氧化铁的掺入对氧化镁稳定氧化锆固体电解质的相组成、微观结构及电性能的影响规律。
XRD测试结果表明氧化铁单独掺杂氧化锆中并不起稳定剂作用,但是与MgO共掺杂后对MgO稳定作用起催化剂作用,促进了其在较少掺入量、较低温度下产生较多的立方相。因此,为了获得预期相组成固体电解质,必须综合协调好氧化铁、氧化镁掺入量与烧结温度的关系。通过SEM测试结果发现一个有趣的现象,掺杂氧化铁的样品发现了特殊的网格状晶形,并且网格状晶形的含量与氧化铁的掺入量具有明显依赖关系。同时氧化铁在适宜的掺入量下能够促进氧化锆固体电解质体系的致密性。
利用交流阻抗谱技术研究了不同组分、不同烧结温度下系列样品的导电性,系统深入的探讨了氧化铁对固体电解质的http://www.999magnet.com/products/131-magnetic-lifter电导特性的影响。研究结果表明,氧化铁的掺入改变了体系的电导特性,增加了体系的电子电导比例,并考察了体系的电导率、离子电导活化能与氧化铁掺入量的关系。
用注射成型技术制备了MgO部分稳定氧化锆固体电解质锆管,并组装成套钢液快速定氧传感器,并在鞍钢和华西钢厂进行了现场定氧测试。
学位年度:2010
Ir-Eu双金属配合物的激发态动力学研究
题名:Ir-Eu双金属配合物的激发态动力学研究
作者:邢亚东
学位授予单位:内蒙古大学
关键词:Ir-Eu双金属配合物;;时间分辨光谱;;传能途径;;量子产率
摘要:
稀土离子具有丰富的能级和4f电子,这使其具有独特的性质,主要应用在发光方面。过渡金属d轨道能级的电子跃迁特性,使过渡金属配合物成为一类很好的“天线”基团。d-f复合配合物可以将激发窗口延伸至可见区,因此在生物检测中有着广泛的应用前景。但是,由于d-f复合物在受到光激发后,不同的激发态能级之间的相互作用Magnetic lifter和传能途径较为复杂,因此研究此类配合物的激发态动力学是很有意义的。
本文合成和表征了两个含有不同桥联配体的IrⅢ-EuⅢ双金属配合物{[(dfqpy)2Ir(μ-phen3f)]3EuCl}C12,{[(dfppy)2Ir(μ-phen5f)]3EuCl}Cl2研究结果表明,两配合物之间的桥联配体的改变导致了,三重态能级和激发态能量传递速率的细微改变,但是两个配合物的总的发光量子产率却有很大区别。通过时间分辨光谱结合Matlab Global-fitting拟合和理论计算的方法,给出了在该体系中能量传递速率常数及能量http://www.999magnet.com/products/131-magnetic-lifter传递效率,两双金属配合物的能量传递效率都很高,都能很好的敏化EuⅢ,使其发射Eu的特征红光,量子产率却有很大的差距,这主要原因应该归于Eu离子的激发态能量的非辐射弛豫。
学位年度:2010
作者:邢亚东
学位授予单位:内蒙古大学
关键词:Ir-Eu双金属配合物;;时间分辨光谱;;传能途径;;量子产率
摘要:
稀土离子具有丰富的能级和4f电子,这使其具有独特的性质,主要应用在发光方面。过渡金属d轨道能级的电子跃迁特性,使过渡金属配合物成为一类很好的“天线”基团。d-f复合配合物可以将激发窗口延伸至可见区,因此在生物检测中有着广泛的应用前景。但是,由于d-f复合物在受到光激发后,不同的激发态能级之间的相互作用Magnetic lifter和传能途径较为复杂,因此研究此类配合物的激发态动力学是很有意义的。
本文合成和表征了两个含有不同桥联配体的IrⅢ-EuⅢ双金属配合物{[(dfqpy)2Ir(μ-phen3f)]3EuCl}C12,{[(dfppy)2Ir(μ-phen5f)]3EuCl}Cl2研究结果表明,两配合物之间的桥联配体的改变导致了,三重态能级和激发态能量传递速率的细微改变,但是两个配合物的总的发光量子产率却有很大区别。通过时间分辨光谱结合Matlab Global-fitting拟合和理论计算的方法,给出了在该体系中能量传递速率常数及能量http://www.999magnet.com/products/131-magnetic-lifter传递效率,两双金属配合物的能量传递效率都很高,都能很好的敏化EuⅢ,使其发射Eu的特征红光,量子产率却有很大的差距,这主要原因应该归于Eu离子的激发态能量的非辐射弛豫。
学位年度:2010
含氮、氧、硫配体构筑的配位聚合物的合成与结构
题名:含氮、氧、硫配体构筑的配位聚合物的合成与结构
作者:杨微
学位授予单位:内蒙古大学
关键词:水热合成;;配位聚合物;;晶体结构;;拓扑
摘要:
本文以设计合成配位聚合物为目标,选用羧酸(1,3,4-噻二唑-2,5-二硫代乙酸(H2btc)、2,2’-联毗啶-3,3’-二甲酸-1,1’-氮氧化物(H2bpdado)和5-硝基间苯二甲酸(O2N-bdc))为构筑单元,通过辅助配体(1,1’-(1,4-丁烷)二(咪唑)(bbi))的调节,与稀土、过渡金属离子反应。采用溶剂热法和水热法合成了4个具有二维、三维结构的配合Magnetic lifter物,测定其单晶结构并对其进行红外光谱分析、X-射线单晶衍射和差热-热重分析表征。配合物的分子式如下：
{Zn(bpdado)(bbi)·H2O}n 1
{Ni2(O2N-bdc)2(bbi)3(H2O)2·2H2O}n 2
{[Ni2(O2N-bdc)2(bbi)2H2O]·4H2O}n 3
[Nd2(btc)3(H2O)5]n 4
配合物1是由2,2’-联吡啶-3,3’-二甲酸-1,1’-氮氧化物和1,1’-(1,4-丁烷)二(咪唑)配体合成的具有8.995×13.502 A2孔洞的二维层状配位聚合物。配合物2和3均为5-硝基间苯二甲酸和1,1’-(1,4-丁烷)二(咪唑)配体合成的三维配位聚合物。配合物4是由柔性配体1,3,4-噻二唑-2,5-二硫代乙酸合成的具有三维结构http://www.999magnet.com/products/131-magnetic-lifter的配位聚合物。配合物4中存在S…S弱作用归因于1,3,4-噻二唑-2,5-二硫代乙酸配体的柔性。
拓扑分析表明,配合物1具有4-连接的(4,4)拓扑结构,配合物2和3具有5-连接的(44,66)拓扑结构,配合物4具有6,8-连接的(37·47·5)(38·48·55·67)拓扑结构。
学位年度:2010
作者:杨微
学位授予单位:内蒙古大学
关键词:水热合成;;配位聚合物;;晶体结构;;拓扑
摘要:
本文以设计合成配位聚合物为目标,选用羧酸(1,3,4-噻二唑-2,5-二硫代乙酸(H2btc)、2,2’-联毗啶-3,3’-二甲酸-1,1’-氮氧化物(H2bpdado)和5-硝基间苯二甲酸(O2N-bdc))为构筑单元,通过辅助配体(1,1’-(1,4-丁烷)二(咪唑)(bbi))的调节,与稀土、过渡金属离子反应。采用溶剂热法和水热法合成了4个具有二维、三维结构的配合Magnetic lifter物,测定其单晶结构并对其进行红外光谱分析、X-射线单晶衍射和差热-热重分析表征。配合物的分子式如下：
{Zn(bpdado)(bbi)·H2O}n 1
{Ni2(O2N-bdc)2(bbi)3(H2O)2·2H2O}n 2
{[Ni2(O2N-bdc)2(bbi)2H2O]·4H2O}n 3
[Nd2(btc)3(H2O)5]n 4
配合物1是由2,2’-联吡啶-3,3’-二甲酸-1,1’-氮氧化物和1,1’-(1,4-丁烷)二(咪唑)配体合成的具有8.995×13.502 A2孔洞的二维层状配位聚合物。配合物2和3均为5-硝基间苯二甲酸和1,1’-(1,4-丁烷)二(咪唑)配体合成的三维配位聚合物。配合物4是由柔性配体1,3,4-噻二唑-2,5-二硫代乙酸合成的具有三维结构http://www.999magnet.com/products/131-magnetic-lifter的配位聚合物。配合物4中存在S…S弱作用归因于1,3,4-噻二唑-2,5-二硫代乙酸配体的柔性。
拓扑分析表明,配合物1具有4-连接的(4,4)拓扑结构,配合物2和3具有5-连接的(44,66)拓扑结构,配合物4具有6,8-连接的(37·47·5)(38·48·55·67)拓扑结构。
学位年度:2010
核壳两亲型聚合物膜电极的构建及其对GOD直接电子转移的促进作用
题名:核壳两亲型聚合物膜电极的构建及其对GOD直接电子转移的促进作用
作者:曹霞
学位授予单位:苏州大学
关键词:核壳两亲型聚合物;;直接电子转移;;葡萄糖氧化酶;;磷钼杂多酸;;修饰电极
摘要:
高分子聚合物因其独特的结构和功能性,作为修饰材料在电化学传感器中得到了广泛的研究和应用。本文将一种具有憎水性核和疏水性壳的两亲性阳离子聚合物微球( Hydrophilic PDMAEMA-protonated corona and hydrophobic polystyrene core,简称PDS)修饰至电极表面,利用其良好的固载能力及生物相容(及相溶)性能,形成稳定性好、导电能力强的聚合物膜修饰电极,考察该聚合物膜对生物酶(GOD)以及无机催化物种(杂多酸)修饰电极性能的影响。旨在探讨和开发此类核壳结构两亲性聚合物在修饰电Magnetic lifter极及生物传感器中的应用。
论文的主要工作及研究结果如下:
第一部分,考察和优化了聚合物膜的成膜条件。通过浸泡的方法将PDS修饰到GC电极上,考察浸泡时间和PDS固含量的影响,得到最优化成膜条件为:浸泡时间10min,PDS固含量0.1056g/mL。通过扫描电镜、循环伏安法等技术研究PDS膜在电极表面形貌和修饰电极的导电性能及稳定性。结果表明,铁氰化钾在PDS膜电极上的氧化还原峰电流明显增大,且△Ep减小,可逆性比裸电极好,说明PDS膜可以促进电极的电子传导能力。
第二部分,将GOD固定在经PDS修饰的玻碳电极(PDS/GC)上,制成GOD/PDS/GC电极。通过扫描电镜(SEM)对其表面形貌表征,结果表明,PDS能将GOD牢固地固定在玻碳电极表面,且GOD在电极表面分布均匀。采用循环伏安法(CV)考察了修饰电极上GOD的电化学行为和电催化性质。其循环伏安曲线上显示出一对可逆的氧化还原峰;在100mV/s扫速下,其式量电位E0为- 0.447 V(vs. SCE,pH 6.24);GOD在PDS/GC电极表面电子转移的表观速率常数k为3.9s-1;根据式量电位E0随缓冲溶液pH值的变化关系,确知GOD发生的直接电化学反应遵从(2e+2H+)机理。表明电极表面的PDS能改变GOD活性中心的微环境,促进GOD与电极之间的直接电子传递。此外,实验结果显示,电极表面的GOD对溶液中的O2有很强的电催化还原作用,在O2饱和体系中,GOD的还原峰峰电流的降低程度与溶http://www.999magnet.com/products/131-magnetic-lifter液中葡萄糖浓度有线性关系,线性范围为0~8mM。总之,PDS不仅具有良好的生物相容性,而且能促使GOD在电极表面发生直接电子转移作用。因此,PDS有望可以作为第三代酶生物传感器中良好的固定酶材料。
第三部分,通过分子间静电作用将Keggin结构磷钼杂多酸(H3PMoO40. xH2O,简称PMo12)吸附在PDS/玻碳电极(PDS/GC)上,制备得到PMo12/PDS膜电极。采用循环伏安技术考察了PDS对PMo12在电极表面的电化学性质以及对杂多酸修饰电极稳定性的影响。实验结果证实,该修饰电极在0.5mol/LH2SO4溶液中的CV曲线上,出现了归属于PMo12的3对可逆氧化还原峰,并且其氧化还原峰电流明显大于单独PMo12修饰电极。该修饰电极对NO2-、IO3-、BrO3-具有很好的电催化还原作用,说明PDS是一种良好的修饰电极聚合物膜材料,这为无机催化活性物种在电极表面的修饰提供了很好的途径。
学位年度:2010
作者:曹霞
学位授予单位:苏州大学
关键词:核壳两亲型聚合物;;直接电子转移;;葡萄糖氧化酶;;磷钼杂多酸;;修饰电极
摘要:
高分子聚合物因其独特的结构和功能性,作为修饰材料在电化学传感器中得到了广泛的研究和应用。本文将一种具有憎水性核和疏水性壳的两亲性阳离子聚合物微球( Hydrophilic PDMAEMA-protonated corona and hydrophobic polystyrene core,简称PDS)修饰至电极表面,利用其良好的固载能力及生物相容(及相溶)性能,形成稳定性好、导电能力强的聚合物膜修饰电极,考察该聚合物膜对生物酶(GOD)以及无机催化物种(杂多酸)修饰电极性能的影响。旨在探讨和开发此类核壳结构两亲性聚合物在修饰电Magnetic lifter极及生物传感器中的应用。
论文的主要工作及研究结果如下:
第一部分,考察和优化了聚合物膜的成膜条件。通过浸泡的方法将PDS修饰到GC电极上,考察浸泡时间和PDS固含量的影响,得到最优化成膜条件为:浸泡时间10min,PDS固含量0.1056g/mL。通过扫描电镜、循环伏安法等技术研究PDS膜在电极表面形貌和修饰电极的导电性能及稳定性。结果表明,铁氰化钾在PDS膜电极上的氧化还原峰电流明显增大,且△Ep减小,可逆性比裸电极好,说明PDS膜可以促进电极的电子传导能力。
第二部分,将GOD固定在经PDS修饰的玻碳电极(PDS/GC)上,制成GOD/PDS/GC电极。通过扫描电镜(SEM)对其表面形貌表征,结果表明,PDS能将GOD牢固地固定在玻碳电极表面,且GOD在电极表面分布均匀。采用循环伏安法(CV)考察了修饰电极上GOD的电化学行为和电催化性质。其循环伏安曲线上显示出一对可逆的氧化还原峰;在100mV/s扫速下,其式量电位E0为- 0.447 V(vs. SCE,pH 6.24);GOD在PDS/GC电极表面电子转移的表观速率常数k为3.9s-1;根据式量电位E0随缓冲溶液pH值的变化关系,确知GOD发生的直接电化学反应遵从(2e+2H+)机理。表明电极表面的PDS能改变GOD活性中心的微环境,促进GOD与电极之间的直接电子传递。此外,实验结果显示,电极表面的GOD对溶液中的O2有很强的电催化还原作用,在O2饱和体系中,GOD的还原峰峰电流的降低程度与溶http://www.999magnet.com/products/131-magnetic-lifter液中葡萄糖浓度有线性关系,线性范围为0~8mM。总之,PDS不仅具有良好的生物相容性,而且能促使GOD在电极表面发生直接电子转移作用。因此,PDS有望可以作为第三代酶生物传感器中良好的固定酶材料。
第三部分,通过分子间静电作用将Keggin结构磷钼杂多酸(H3PMoO40. xH2O,简称PMo12)吸附在PDS/玻碳电极(PDS/GC)上,制备得到PMo12/PDS膜电极。采用循环伏安技术考察了PDS对PMo12在电极表面的电化学性质以及对杂多酸修饰电极稳定性的影响。实验结果证实,该修饰电极在0.5mol/LH2SO4溶液中的CV曲线上,出现了归属于PMo12的3对可逆氧化还原峰,并且其氧化还原峰电流明显大于单独PMo12修饰电极。该修饰电极对NO2-、IO3-、BrO3-具有很好的电催化还原作用,说明PDS是一种良好的修饰电极聚合物膜材料,这为无机催化活性物种在电极表面的修饰提供了很好的途径。
学位年度:2010
BaBPO_5中Sm~（2+）还原与稳定性研究
题名:BaBPO_5中Sm~（2+）还原与稳定性研究
作者:赵婉雪
学位授予单位:苏州大学
关键词:硼磷酸钡;;稀土离子;;Sm~(2+);;发光;;X射线辐照还原
摘要:
自从稀土离子中Sm~(2+)的掺杂材料实现了室温的永久光谱烧孔现象(PSHB),便引起了人们广泛的研究兴趣。通常,Sm离子在基质中稳定的价态是三价,必须把Sm~(3+)还原为Sm~(2+)离子。最常用的制备方法是在还原气氛下烧结制备材料。另外,Sm~(3+)在X射线或高密度飞秒激光辐射下也可以实现Sm~(3+)的还原。这两种还Neodymium magnets原方法,各有优势,通过对比两种方法还原后样品的发光性能以及稳定性,可为PSHB材料制备选定还原手段提供数据上的支持。
本课题采用BaBPO5作为研究基质,在基质中掺杂Sm~(3+)离子,实验采用高温固相反应法合成样品,通过高温还原气氛(H2 /He)煅烧和X射线照射法实现Sm~(3+)至Sm~(2+)的还原,表征BaBPO5基质中Sm~(2+)离子发光性能,对样品进行光漂白效果和热稳定性测试,研究两种不同的还原机理和稳定性。
论文第二章为实验部分,通过高温固相法合成BaBPO5样品。介绍了本课题所采用的一系列测试方法,如X射线粉末衍射测试,扫描电子显微镜形貌分析,红外吸收光谱,激发和发射光谱,发光衰减等等。
论文第三章研究了Sm~(3+)的两种还原方法,并对其进行了发光表征。常温下制备的Sm掺杂BaBPO5得到的样品为三价。文章制备Ba1-xSmxBPO5 (x=0-0.1, 0-10%)样品,分析了Sm~(3+)离子的发光特征和发光猝灭。采用高温还原气氛(H2 /He)煅烧和X射线照射法还原Sm~(2+)离子。实验发现,两种方法均可有效地实现在BaBPO5基质中Sm~(3+)→Sm~(2+)的还原,而发光和衰减测试效果表明:利用两种方法得到的Sm~(2+)具有不同的发光特性。
第四章对Sm~(2+)的光漂白效应和热稳定性进行了研究。在488 nm的Ar+激光照射下,两种方法得到的Sm~(2+)的发光强度均降低,即均具有光漂白作用,但X射线辐照还原的5D0→7F0跃迁发光强度在120 min内衰减了52%,而H2还原后的样品只减弱到了初始强度的10%左右。因此,在BaBPO5之中Sm~(2+)的发光和稳定性强烈地依赖于其制备方法。
在第五章中,论文通过热释光和光诱http://www.chinamagnets.biz/导吸收测试分析探讨了Sm~(2+)的还原机理。在氢气还原气氛下,Sm~(2+)的还原过程较为简单,多来自于BBP基质的本征缺陷存在,例如:由于B和O挥发形成的空位缺陷(VB)”’,和(Vo)···以及离子置换形成的缺陷(PB)···。而X射线辐照还原后,样品的缺陷更加丰富而且不稳定,BaBPO5在空气中烧结,Sm是以Sm~(3+)离子的形式进入基质晶格,然后在X射线的辐照下还原为Sm~(2+)离子。
虽然Sm~(2+)离子掺杂硼磷酸盐发光的探索越来越受到关注,但直至目前,据本人了解,还仍然没有利用X射线方法实现BaBPO5中Sm~(2+)离子还原的报道,本课题不但实现了X射线和H2气氛下的Sm~(2+)离子的还原,更深入探讨了还原机理,为这一领域做出贡献。
学位年度:2010
作者:赵婉雪
学位授予单位:苏州大学
关键词:硼磷酸钡;;稀土离子;;Sm~(2+);;发光;;X射线辐照还原
摘要:
自从稀土离子中Sm~(2+)的掺杂材料实现了室温的永久光谱烧孔现象(PSHB),便引起了人们广泛的研究兴趣。通常,Sm离子在基质中稳定的价态是三价,必须把Sm~(3+)还原为Sm~(2+)离子。最常用的制备方法是在还原气氛下烧结制备材料。另外,Sm~(3+)在X射线或高密度飞秒激光辐射下也可以实现Sm~(3+)的还原。这两种还Neodymium magnets原方法,各有优势,通过对比两种方法还原后样品的发光性能以及稳定性,可为PSHB材料制备选定还原手段提供数据上的支持。
本课题采用BaBPO5作为研究基质,在基质中掺杂Sm~(3+)离子,实验采用高温固相反应法合成样品,通过高温还原气氛(H2 /He)煅烧和X射线照射法实现Sm~(3+)至Sm~(2+)的还原,表征BaBPO5基质中Sm~(2+)离子发光性能,对样品进行光漂白效果和热稳定性测试,研究两种不同的还原机理和稳定性。
论文第二章为实验部分,通过高温固相法合成BaBPO5样品。介绍了本课题所采用的一系列测试方法,如X射线粉末衍射测试,扫描电子显微镜形貌分析,红外吸收光谱,激发和发射光谱,发光衰减等等。
论文第三章研究了Sm~(3+)的两种还原方法,并对其进行了发光表征。常温下制备的Sm掺杂BaBPO5得到的样品为三价。文章制备Ba1-xSmxBPO5 (x=0-0.1, 0-10%)样品,分析了Sm~(3+)离子的发光特征和发光猝灭。采用高温还原气氛(H2 /He)煅烧和X射线照射法还原Sm~(2+)离子。实验发现,两种方法均可有效地实现在BaBPO5基质中Sm~(3+)→Sm~(2+)的还原,而发光和衰减测试效果表明:利用两种方法得到的Sm~(2+)具有不同的发光特性。
第四章对Sm~(2+)的光漂白效应和热稳定性进行了研究。在488 nm的Ar+激光照射下,两种方法得到的Sm~(2+)的发光强度均降低,即均具有光漂白作用,但X射线辐照还原的5D0→7F0跃迁发光强度在120 min内衰减了52%,而H2还原后的样品只减弱到了初始强度的10%左右。因此,在BaBPO5之中Sm~(2+)的发光和稳定性强烈地依赖于其制备方法。
在第五章中,论文通过热释光和光诱http://www.chinamagnets.biz/导吸收测试分析探讨了Sm~(2+)的还原机理。在氢气还原气氛下,Sm~(2+)的还原过程较为简单,多来自于BBP基质的本征缺陷存在,例如:由于B和O挥发形成的空位缺陷(VB)”’,和(Vo)···以及离子置换形成的缺陷(PB)···。而X射线辐照还原后,样品的缺陷更加丰富而且不稳定,BaBPO5在空气中烧结,Sm是以Sm~(3+)离子的形式进入基质晶格,然后在X射线的辐照下还原为Sm~(2+)离子。
虽然Sm~(2+)离子掺杂硼磷酸盐发光的探索越来越受到关注,但直至目前,据本人了解,还仍然没有利用X射线方法实现BaBPO5中Sm~(2+)离子还原的报道,本课题不但实现了X射线和H2气氛下的Sm~(2+)离子的还原,更深入探讨了还原机理,为这一领域做出贡献。
学位年度:2010
基于分子印迹分离纯化绿原酸与荧光仿生识别技术研究
题名:基于分子印迹分离纯化绿原酸与荧光仿生识别技术研究
作者:顾晓红
学位授予单位:苏州大学
关键词:分子印迹;;绿原酸;;分离纯化;;三聚氰胺;;仿生识别检测
摘要:
分子印迹技术是从仿生角度,采用人工方法制备对模板分子具有专一性结合作用的聚合物的技术。分子印迹聚合物在分离提纯、免疫分析、酶模拟以及生物模拟传感器等许多方面显示出广泛的应用前景。
本论文对两种新型分子印迹聚合物,即绿原酸磁性印迹聚合微球(MIPMs)和三聚氰胺荧光仿生识别聚合物膜的制备方法及吸附性能进行了较认真的系统的研究,并获得了良好的结果。论文的主要内容如下:
(1)对分子印迹技术的基本原理、Neodymium magnets方法和应用做了比较全面的综述,对分子印迹技术未来的发展趋势进行了分析和展望。
(2)选用自制的Fe3O4纳米粒为磁性组分,绿原酸为模板分子,甲基丙烯酸为功能单体,三羟甲基丙烷三丙烯酸酯为交联剂,采用水包油包水多重乳液悬浮聚合法制备了MIPMs。采用透射电子显微镜、红外光谱、热重分析、振动样品磁强计对其形态、大小、组成和磁性能进行了表征。优化了MIPMs的制备、洗脱和吸附条件;采用静态平衡吸附实验研究了MIPMs的吸附性能,发现其对模板分子表现出较好的特异性吸附,进一步的Scatchard分析表明其存在两类不同类型的结合位点。考察了MIPMs的吸附动力学性质和再生性能。最后,将MIPMs实际应用于金银花提取液中绿原酸活性成分的分离纯化,对中药复杂体系中有效组分的分离纯化具有潜在的应用前景。
(3)首先在相转移催化剂聚乙二醇600的存在下,以固体氢氧化钾为碱性试剂合成了α取代的具有可聚合双键的β-二酮配体,而后同甲基丙烯酸和模板分子三聚氰胺一起与稀土金属铕配位,形成具有可聚合端基双键、性能优良的铕多元配位复合物荧光载体。然后,将该荧光载体与聚合单体苯乙烯在热引发下共聚形成荧光性能的分子探针粘稠液,涂布于经过硅烷化处理的玻片上,制成三聚氰胺荧光仿生识别膜,其对三聚氰胺具有一定的仿生识别和检测功能。采用紫外光谱、红外光谱、核磁共振氢谱、热重分http://www.chinamagnets.biz/析、荧光光谱等对所制备的新型β-二酮配体、铕多元配位复合物和荧光仿生识别膜进行了一系列分析与表征。优化了荧光仿生识别膜的制备方法,经模板分子的洗脱和再吸附,研究其对三聚氰胺的分析特性及应用。本试验充分利用了分子印迹技术,并于荧光分析相结合,大大提高了对三聚氰胺的检测能力,方法简单,操作方便,敏感性好、适应性广、成本低,易于推广和普及。
学位年度:2010
作者:顾晓红
学位授予单位:苏州大学
关键词:分子印迹;;绿原酸;;分离纯化;;三聚氰胺;;仿生识别检测
摘要:
分子印迹技术是从仿生角度,采用人工方法制备对模板分子具有专一性结合作用的聚合物的技术。分子印迹聚合物在分离提纯、免疫分析、酶模拟以及生物模拟传感器等许多方面显示出广泛的应用前景。
本论文对两种新型分子印迹聚合物,即绿原酸磁性印迹聚合微球(MIPMs)和三聚氰胺荧光仿生识别聚合物膜的制备方法及吸附性能进行了较认真的系统的研究,并获得了良好的结果。论文的主要内容如下:
(1)对分子印迹技术的基本原理、Neodymium magnets方法和应用做了比较全面的综述,对分子印迹技术未来的发展趋势进行了分析和展望。
(2)选用自制的Fe3O4纳米粒为磁性组分,绿原酸为模板分子,甲基丙烯酸为功能单体,三羟甲基丙烷三丙烯酸酯为交联剂,采用水包油包水多重乳液悬浮聚合法制备了MIPMs。采用透射电子显微镜、红外光谱、热重分析、振动样品磁强计对其形态、大小、组成和磁性能进行了表征。优化了MIPMs的制备、洗脱和吸附条件;采用静态平衡吸附实验研究了MIPMs的吸附性能,发现其对模板分子表现出较好的特异性吸附,进一步的Scatchard分析表明其存在两类不同类型的结合位点。考察了MIPMs的吸附动力学性质和再生性能。最后,将MIPMs实际应用于金银花提取液中绿原酸活性成分的分离纯化,对中药复杂体系中有效组分的分离纯化具有潜在的应用前景。
(3)首先在相转移催化剂聚乙二醇600的存在下,以固体氢氧化钾为碱性试剂合成了α取代的具有可聚合双键的β-二酮配体,而后同甲基丙烯酸和模板分子三聚氰胺一起与稀土金属铕配位,形成具有可聚合端基双键、性能优良的铕多元配位复合物荧光载体。然后,将该荧光载体与聚合单体苯乙烯在热引发下共聚形成荧光性能的分子探针粘稠液,涂布于经过硅烷化处理的玻片上,制成三聚氰胺荧光仿生识别膜,其对三聚氰胺具有一定的仿生识别和检测功能。采用紫外光谱、红外光谱、核磁共振氢谱、热重分http://www.chinamagnets.biz/析、荧光光谱等对所制备的新型β-二酮配体、铕多元配位复合物和荧光仿生识别膜进行了一系列分析与表征。优化了荧光仿生识别膜的制备方法,经模板分子的洗脱和再吸附,研究其对三聚氰胺的分析特性及应用。本试验充分利用了分子印迹技术,并于荧光分析相结合,大大提高了对三聚氰胺的检测能力,方法简单,操作方便,敏感性好、适应性广、成本低,易于推广和普及。
学位年度:2010
2012年1月2日星期一
Fe（Cu）掺杂Ge（Si）基稀磁半导体薄膜的结构及磁性研究
题名:Fe（Cu）掺杂Ge（Si）基稀磁半导体薄膜的结构及磁性研究
作者:高卫霞
学位授予单位:河北师范大学
关键词:磁性半导体;;离子注入;;磁畴;;输运性质;;霍尔效应
摘要:
在当今信息高速发展的时代,信息传输和存储仍然是通过传统的方法—分别控制电子的电荷和电子的自旋来实现。随着人们对信息量需求的日益增大,传统的半导体和铁磁体独立工作带来的不足,越来越凸显出来,集电子的电荷和自旋于一体的稀释磁性半导体材料已成为当前最令人感兴趣的研究领域。稀释磁性半导体由于过渡Magnetic lifter族或稀土族磁性元素的掺入,使得该类材料与传统的半导体相比,出现了许多奇异特性,具备良好的应用前景。
Mn掺杂Ⅳ族基稀磁半导体的理论研究和实验进展都已取得了可喜成果,但是关于其磁性起源和具体器件的应用还有待更进一步的研究。本工作选取了过渡族元素Fe和Cu,对Si/Ge基半导体掺杂,具体工作如下:
1.用磁控溅射法在Si基底上制备了Fe掺杂Ge1-xFex系列薄膜,基底温度为473 K,经873 K真空后退火20 min得到样品。X射线衍射(XRD)结构检测显示所有样品具有Ge的立方结构,没有发现其他杂质相。样品中的Fe主要以Fe2+离子形式存在,同时含有少量的Fe0;Ge元素主要以Ge0形式存在于样品,含有少量的Ge-O键和Ge-Fe键。Fe掺杂浓度为11.3%样品中有Fe3+离子存在。磁性测量显示样品在低温下具有弱的铁磁性,居里温度约为300 K,铁磁性来源于随机分布的磁性Fe原子。
2.用金属蒸发真空弧和考夫曼离子注入技术,在n-Si(100)基片中共注入Fe、N离子,制备Fe、N共掺的Si(Fe,N)薄膜样品。X射线衍射(XRD)结构分析表明,离子注入没有改变基底的立方晶格结构,也没有形成其他杂质第二相。X射线吸收精细结构(XAFS)表明低注入剂量样品中Fe离子处于替代位,高剂量注入样品中有FeSi2化合物形成。磁力显微镜(MFM)观察到磁畴结构,磁性测量显示低注入剂量(2.0×1016 cm-2)样品有最大磁矩约0.46μB/Fe,原位退火和后退火都减弱了样品的铁磁性。Hall测量显示样品是n型传导,饱和磁化强度随着电子载流子浓度的增大而减小。样品的磁性不依赖于载流子,而是http://www.999magnet.com/products/131-magnetic-lifter来源于处于替代位的Fe磁性原子。
3.用金属蒸发真空弧离子注入技术,在n-Si(100)基片中注入Cu离子得到Si:Cu薄膜。X射线衍射(XRD)测量显示不同剂量的Cu离子注入后样品均由单晶Si变为多晶Si晶格结构,同时有Cu间隙、Si间隙和Si空位等缺陷形成,但是没有发现其他杂质相。常注入态样品中,Cu以Cu+离子形式存在,经N2气氛围快速热退火后,有少部分Cu2+离子出现。Hall效应测量表明Cu+离子注入使得Si母体由n型传导变为p型。磁性测量显示样品具有室温铁磁性,该磁性来源于空穴载流子传递的Cu+离子与Si空位间的铁磁相互作用。
学位年度:2010
作者:高卫霞
学位授予单位:河北师范大学
关键词:磁性半导体;;离子注入;;磁畴;;输运性质;;霍尔效应
摘要:
在当今信息高速发展的时代,信息传输和存储仍然是通过传统的方法—分别控制电子的电荷和电子的自旋来实现。随着人们对信息量需求的日益增大,传统的半导体和铁磁体独立工作带来的不足,越来越凸显出来,集电子的电荷和自旋于一体的稀释磁性半导体材料已成为当前最令人感兴趣的研究领域。稀释磁性半导体由于过渡Magnetic lifter族或稀土族磁性元素的掺入,使得该类材料与传统的半导体相比,出现了许多奇异特性,具备良好的应用前景。
Mn掺杂Ⅳ族基稀磁半导体的理论研究和实验进展都已取得了可喜成果,但是关于其磁性起源和具体器件的应用还有待更进一步的研究。本工作选取了过渡族元素Fe和Cu,对Si/Ge基半导体掺杂,具体工作如下:
1.用磁控溅射法在Si基底上制备了Fe掺杂Ge1-xFex系列薄膜,基底温度为473 K,经873 K真空后退火20 min得到样品。X射线衍射(XRD)结构检测显示所有样品具有Ge的立方结构,没有发现其他杂质相。样品中的Fe主要以Fe2+离子形式存在,同时含有少量的Fe0;Ge元素主要以Ge0形式存在于样品,含有少量的Ge-O键和Ge-Fe键。Fe掺杂浓度为11.3%样品中有Fe3+离子存在。磁性测量显示样品在低温下具有弱的铁磁性,居里温度约为300 K,铁磁性来源于随机分布的磁性Fe原子。
2.用金属蒸发真空弧和考夫曼离子注入技术,在n-Si(100)基片中共注入Fe、N离子,制备Fe、N共掺的Si(Fe,N)薄膜样品。X射线衍射(XRD)结构分析表明,离子注入没有改变基底的立方晶格结构,也没有形成其他杂质第二相。X射线吸收精细结构(XAFS)表明低注入剂量样品中Fe离子处于替代位,高剂量注入样品中有FeSi2化合物形成。磁力显微镜(MFM)观察到磁畴结构,磁性测量显示低注入剂量(2.0×1016 cm-2)样品有最大磁矩约0.46μB/Fe,原位退火和后退火都减弱了样品的铁磁性。Hall测量显示样品是n型传导,饱和磁化强度随着电子载流子浓度的增大而减小。样品的磁性不依赖于载流子,而是http://www.999magnet.com/products/131-magnetic-lifter来源于处于替代位的Fe磁性原子。
3.用金属蒸发真空弧离子注入技术,在n-Si(100)基片中注入Cu离子得到Si:Cu薄膜。X射线衍射(XRD)测量显示不同剂量的Cu离子注入后样品均由单晶Si变为多晶Si晶格结构,同时有Cu间隙、Si间隙和Si空位等缺陷形成,但是没有发现其他杂质相。常注入态样品中,Cu以Cu+离子形式存在,经N2气氛围快速热退火后,有少部分Cu2+离子出现。Hall效应测量表明Cu+离子注入使得Si母体由n型传导变为p型。磁性测量显示样品具有室温铁磁性,该磁性来源于空穴载流子传递的Cu+离子与Si空位间的铁磁相互作用。
学位年度:2010
复合钙钛矿锰氧化物的制备与磁电特性的研究
题名:复合钙钛矿锰氧化物的制备与磁电特性的研究
作者:范素丽
学位授予单位:河北师范大学
关键词:钙钛矿锰氧化物;;低场磁电阻效应;;复合系统;;隧穿效应
摘要:
近年来,在形如R1-xAxMnO3(R是稀土元素,A是二价阳离子)的锰基钙钛矿多晶材料中的颗粒边界效应引起人们极大的研究兴趣。早期人们在这类材料中发现庞磁电阻效应(CMR),但CMR仅仅出现在居里温度(Tc)附近狭窄的温度范围,而且需要几个特斯拉的高磁场才可以实现,因而限制了它的应用。最近,人们发现在锰基钙钛矿多晶材料中颗粒边界效应强烈地影响其物理性能,最吸引人的特征就是在较低的磁场下就可以获得很高的磁电阻,而且低场磁电阻(LFMR)出现在整个绝缘体金属转变温度(Tp)以下宽的温度范围。一般认为,这种低场磁电阻是由于载流子通过颗粒边界的能量势垒发生自旋极化隧穿Neodymium Magnets而引起的。颗粒边界的无序结构是载流子能量势垒的主要原因,因此对颗粒边界进行优化处理可以改善这类磁电阻,最有效的方法就是引入第二相形成锰基钙钛矿颗粒复合材料。本论文主要以钙钛矿锰氧化物La_(0.67)Sr_(0.33)MnO_3 (LSMO)颗粒体系为研究对象,通过在其颗粒边界引入不同性质的第二相材料对颗粒边界进行改性,并对复合体系的电、磁输运行为进行研究,从而为提高低场磁电阻效应提供实验和理论基础。主要研究结果包括如下几方面:
1.用溶胶凝胶法制备出单相的La_(0.67)Sr_(0.33)MnO_3、Pr0.67Ca0.33MnO3(PCMO)、Sm_(0.67)Ca_(0.33)MnO_3(SCMO),研究了它们的结构、磁性能及电输运。
2.将单相的La_(0.67)Sr_(0.33)MnO_3、Pr0.67Ca0.33MnO3按一定的比例混合、研磨、压片,在合适的温度下进行烧结,得到两相共存的复合锰氧化物(1-x)La_(0.67)Sr_(0.33)MnO_3 /xPr0.67Ca0.33MnO3(LSMO/PCMO)。随着PCMO含量增加,LSMO/PCMO复合样品的磁化强度显著降低,在PCMO电荷有序附近及其以下温区存在较强的磁耦合;复合体系的导电性下降,电阻率增大,电阻率峰值ρTp向低温移动,金属绝缘体的转变峰宽变窄;在低温下样品的低场磁电阻有所提高、高场磁电阻增http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets大很多;由于颗粒间的隧穿效应样品存在低温电阻率极小值现象。
3.按同样的方法得到两相共存的复合锰氧化物(1-x)La_(0.67)Sr_(0.33)MnO_3 /xSm67Ca0.33MnO3(LSMO/SCMO)。LSMO/SCMO复合样品存在两个磁转变温度,随着SCMO含量增加,样品的磁性降低,复合样品LSMO与SCMO颗粒间存在磁耦合;LSMO颗粒周围的SCMO颗粒增多,使其相邻间的交换作用减弱,复合体系的导电性下降,电阻率增大,电阻率峰值ρTp向低温移动,金属绝缘体的转变峰宽变窄。
学位年度:2010
作者:范素丽
学位授予单位:河北师范大学
关键词:钙钛矿锰氧化物;;低场磁电阻效应;;复合系统;;隧穿效应
摘要:
近年来,在形如R1-xAxMnO3(R是稀土元素,A是二价阳离子)的锰基钙钛矿多晶材料中的颗粒边界效应引起人们极大的研究兴趣。早期人们在这类材料中发现庞磁电阻效应(CMR),但CMR仅仅出现在居里温度(Tc)附近狭窄的温度范围,而且需要几个特斯拉的高磁场才可以实现,因而限制了它的应用。最近,人们发现在锰基钙钛矿多晶材料中颗粒边界效应强烈地影响其物理性能,最吸引人的特征就是在较低的磁场下就可以获得很高的磁电阻,而且低场磁电阻(LFMR)出现在整个绝缘体金属转变温度(Tp)以下宽的温度范围。一般认为,这种低场磁电阻是由于载流子通过颗粒边界的能量势垒发生自旋极化隧穿Neodymium Magnets而引起的。颗粒边界的无序结构是载流子能量势垒的主要原因,因此对颗粒边界进行优化处理可以改善这类磁电阻,最有效的方法就是引入第二相形成锰基钙钛矿颗粒复合材料。本论文主要以钙钛矿锰氧化物La_(0.67)Sr_(0.33)MnO_3 (LSMO)颗粒体系为研究对象,通过在其颗粒边界引入不同性质的第二相材料对颗粒边界进行改性,并对复合体系的电、磁输运行为进行研究,从而为提高低场磁电阻效应提供实验和理论基础。主要研究结果包括如下几方面:
1.用溶胶凝胶法制备出单相的La_(0.67)Sr_(0.33)MnO_3、Pr0.67Ca0.33MnO3(PCMO)、Sm_(0.67)Ca_(0.33)MnO_3(SCMO),研究了它们的结构、磁性能及电输运。
2.将单相的La_(0.67)Sr_(0.33)MnO_3、Pr0.67Ca0.33MnO3按一定的比例混合、研磨、压片,在合适的温度下进行烧结,得到两相共存的复合锰氧化物(1-x)La_(0.67)Sr_(0.33)MnO_3 /xPr0.67Ca0.33MnO3(LSMO/PCMO)。随着PCMO含量增加,LSMO/PCMO复合样品的磁化强度显著降低,在PCMO电荷有序附近及其以下温区存在较强的磁耦合;复合体系的导电性下降,电阻率增大,电阻率峰值ρTp向低温移动,金属绝缘体的转变峰宽变窄;在低温下样品的低场磁电阻有所提高、高场磁电阻增http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets大很多;由于颗粒间的隧穿效应样品存在低温电阻率极小值现象。
3.按同样的方法得到两相共存的复合锰氧化物(1-x)La_(0.67)Sr_(0.33)MnO_3 /xSm67Ca0.33MnO3(LSMO/SCMO)。LSMO/SCMO复合样品存在两个磁转变温度,随着SCMO含量增加,样品的磁性降低,复合样品LSMO与SCMO颗粒间存在磁耦合;LSMO颗粒周围的SCMO颗粒增多,使其相邻间的交换作用减弱,复合体系的导电性下降,电阻率增大,电阻率峰值ρTp向低温移动,金属绝缘体的转变峰宽变窄。
学位年度:2010
Nd和Te掺杂对双相复合材料La_（0.6）Sr_（0.1）MnO_3结构和磁性的影响
题名:Nd和Te掺杂对双相复合材料La_（0.6）Sr_（0.1）MnO_3结构和磁性的影响
作者:李岩峰
学位授予单位:河北师范大学
关键词:钙钛矿结构;;有效离子半径;;掺杂;;居里温度
摘要:
在过去的十几年间,由于具有潜在的应用前景,人们对ABO3型掺杂钙钛矿锰氧化物R1-xMxMnO3 (R是稀土元素,M为二价碱土元素)的磁性和输运性质进行了大量研究。其中R和M在A位,Mn在B位。对于这些材料的磁输运性质,可以应用电子在Mn3+-O2?-Mn4+离子之间传导的双交换机制进行解释。针对A1-xMnO3型掺杂钙钛矿锰氧化物研究中存在的物理问题,我们研究组提出了A1-xBO3型钙钛矿材料中Neodymium Magnets空位问题的物理模型,认为在钙钛矿结构中,由于AO间距约为BO间距的2倍,即A位间隙明显大于B位间隙,在制备样品的高温热处理过程中,离子应优先占据间隙较大的A位;A型离子的不足,应由B型离子补足;如果有空位,应该存在于B位,而不是在A位;B位空位的含量应与样品的制备条件有关。
名义成分为La0.6Sr0.1MnO3的锰氧化物显然属于A1-xBO3型钙钛矿材料,实际为含有钙钛矿相和少量Mn3O4的双相复合材料。在本论文中,我们研究了Nd和Te掺杂对这种双相复合材料结构和磁性的影响,探讨了钙钛矿相A位平均离子半径和掺杂离子的半径与Mn3O4相含量的关系。
1、在名义成分为La0.6Sr0.1MnO3的双相复合材料中掺杂Nd,利用固相反应法制备了名义成分为La0.6-xNdxSr0.1MnO3(x=0.0,0.1,0.2,0.3,0.4)的粉体样品。使用X射线衍射仪测量了室温下样品的衍射谱,发现所制备样品都是双相复合材料,主相为钙钛矿相,次相为Mn3O4相,并且Mn3O4相含量随着Nd掺杂量x的增加而减少。x为0.0和0.1的两个样品具有菱面体结构,属于R 3c空间群,一个晶胞中包含6组ABO3离子。x≥0.2的样品为正交结构,空间群为Pbnm,一个晶胞中包含4组ABO3离子。利用X’Pert HighScore Plus软件进行衍射谱逐峰拟合,发现Mn3O4相与钙钛矿相主衍射峰强度的比值随着Nd含量x的增加逐渐减小。通过晶体缺陷理论解释了这一有趣的现象:在名义成分为La0.6Sr0.1MnO3的材料中,由于Mn离子含量比La和Sr离子含量之和多30%,并且Mn2+离子的有效半径显著小于La3+和Sr2+离子,导致一部分Mn以Mn2+离子的形式进入钙钛矿相的A位,另一部分Mn形成Mn3O4次相。因为Nd3+有效离子半径比La3+和Sr2+离子都小,随着Nd对La的替代,钙钛矿相的A位平均离子半径逐渐减小,致使晶胞体积减小,进入A位的Mn2+离子含量增加,从而导致形成http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets的Mn3O4相含量就会逐渐减少。在0.05T的外磁场下,测量了样品的磁化强度随温度变化的(σ-T)曲线。随着温度的增加,样品都经历了由铁磁性到顺磁性的转变过程。随着x的增加转变区域向低温移动。另外,居里温度随着Mn-O-Mn键角Θ的减小而降低。
2、在名义成分为La0.6Sr0.1MnO3的双相复合材料中掺杂Te,利用溶胶-凝胶法制备了名义成分为La0.6Sr0.1TexMnO3(x=0.00,0.05,0.10,0.15,0.20)的系列样品,最高烧结温度为1473K。发现煅烧温度低于1273K时,样品中存在含Te的次相,经1473K煅烧后,几乎全部的Te离子和一部分Mn离子挥发了。
XRD谱表明,经1073和1273K烧结后,掺Te的样品都含有钙钛矿相、Mn3O4相和含有Te的第三相。然而,经1473K烧结后,样品只含有钙钛矿相和Mn3O4两相。利用X’Pert HighScore Plus软件获得了衍射峰强度,计算了经1073,1273和1473K热处理后的样品中第三相和Mn3O4相的主衍射峰强度I3和IM分别与钙钛矿相的主衍射峰强度IP的比值。IM/IP的值几乎不变,而对于经1073和1273K烧结后的样品,随着Te掺杂量的增加,I3/IP的值显著增加。但是经1473 K烧结后的样品I3/IP的值变为0。使用X射线能量散射谱仪对样品La0.6Sr0.1Te0.2MnO3中的Te元素含量进行了测试。经1273 K烧结后的样品中有很明显的Te元素峰。而经1473K烧结后的样品中没有发现Te元素的峰。另外,经1473K烧结后与烧结前相比,Mn与La的含量比值有所减小。利用估算不同化合价离子数目比的量子力学模型估算了La0.6Sr0.1TexMnO3材料中Te3+离子的含量,发现各样品中Te3+离子的含量都小于1%。利用Rietveld精修对XRD衍射数据进行了拟合。发现晶胞体积V,Mn–O键长d,Mn–O–Mn键角Θ都没有明显的变化。磁性研究表明,样品的居里温度也没有明显的变化。所有这些分析结果表明,几乎所有的Te离子和一部分Mn离子在1473K的样品烧结过程中挥发了。
学位年度:2010
作者:李岩峰
学位授予单位:河北师范大学
关键词:钙钛矿结构;;有效离子半径;;掺杂;;居里温度
摘要:
在过去的十几年间,由于具有潜在的应用前景,人们对ABO3型掺杂钙钛矿锰氧化物R1-xMxMnO3 (R是稀土元素,M为二价碱土元素)的磁性和输运性质进行了大量研究。其中R和M在A位,Mn在B位。对于这些材料的磁输运性质,可以应用电子在Mn3+-O2?-Mn4+离子之间传导的双交换机制进行解释。针对A1-xMnO3型掺杂钙钛矿锰氧化物研究中存在的物理问题,我们研究组提出了A1-xBO3型钙钛矿材料中Neodymium Magnets空位问题的物理模型,认为在钙钛矿结构中,由于AO间距约为BO间距的2倍,即A位间隙明显大于B位间隙,在制备样品的高温热处理过程中,离子应优先占据间隙较大的A位;A型离子的不足,应由B型离子补足;如果有空位,应该存在于B位,而不是在A位;B位空位的含量应与样品的制备条件有关。
名义成分为La0.6Sr0.1MnO3的锰氧化物显然属于A1-xBO3型钙钛矿材料,实际为含有钙钛矿相和少量Mn3O4的双相复合材料。在本论文中,我们研究了Nd和Te掺杂对这种双相复合材料结构和磁性的影响,探讨了钙钛矿相A位平均离子半径和掺杂离子的半径与Mn3O4相含量的关系。
1、在名义成分为La0.6Sr0.1MnO3的双相复合材料中掺杂Nd,利用固相反应法制备了名义成分为La0.6-xNdxSr0.1MnO3(x=0.0,0.1,0.2,0.3,0.4)的粉体样品。使用X射线衍射仪测量了室温下样品的衍射谱,发现所制备样品都是双相复合材料,主相为钙钛矿相,次相为Mn3O4相,并且Mn3O4相含量随着Nd掺杂量x的增加而减少。x为0.0和0.1的两个样品具有菱面体结构,属于R 3c空间群,一个晶胞中包含6组ABO3离子。x≥0.2的样品为正交结构,空间群为Pbnm,一个晶胞中包含4组ABO3离子。利用X’Pert HighScore Plus软件进行衍射谱逐峰拟合,发现Mn3O4相与钙钛矿相主衍射峰强度的比值随着Nd含量x的增加逐渐减小。通过晶体缺陷理论解释了这一有趣的现象:在名义成分为La0.6Sr0.1MnO3的材料中,由于Mn离子含量比La和Sr离子含量之和多30%,并且Mn2+离子的有效半径显著小于La3+和Sr2+离子,导致一部分Mn以Mn2+离子的形式进入钙钛矿相的A位,另一部分Mn形成Mn3O4次相。因为Nd3+有效离子半径比La3+和Sr2+离子都小,随着Nd对La的替代,钙钛矿相的A位平均离子半径逐渐减小,致使晶胞体积减小,进入A位的Mn2+离子含量增加,从而导致形成http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets的Mn3O4相含量就会逐渐减少。在0.05T的外磁场下,测量了样品的磁化强度随温度变化的(σ-T)曲线。随着温度的增加,样品都经历了由铁磁性到顺磁性的转变过程。随着x的增加转变区域向低温移动。另外,居里温度随着Mn-O-Mn键角Θ的减小而降低。
2、在名义成分为La0.6Sr0.1MnO3的双相复合材料中掺杂Te,利用溶胶-凝胶法制备了名义成分为La0.6Sr0.1TexMnO3(x=0.00,0.05,0.10,0.15,0.20)的系列样品,最高烧结温度为1473K。发现煅烧温度低于1273K时,样品中存在含Te的次相,经1473K煅烧后,几乎全部的Te离子和一部分Mn离子挥发了。
XRD谱表明,经1073和1273K烧结后,掺Te的样品都含有钙钛矿相、Mn3O4相和含有Te的第三相。然而,经1473K烧结后,样品只含有钙钛矿相和Mn3O4两相。利用X’Pert HighScore Plus软件获得了衍射峰强度,计算了经1073,1273和1473K热处理后的样品中第三相和Mn3O4相的主衍射峰强度I3和IM分别与钙钛矿相的主衍射峰强度IP的比值。IM/IP的值几乎不变,而对于经1073和1273K烧结后的样品,随着Te掺杂量的增加,I3/IP的值显著增加。但是经1473 K烧结后的样品I3/IP的值变为0。使用X射线能量散射谱仪对样品La0.6Sr0.1Te0.2MnO3中的Te元素含量进行了测试。经1273 K烧结后的样品中有很明显的Te元素峰。而经1473K烧结后的样品中没有发现Te元素的峰。另外,经1473K烧结后与烧结前相比,Mn与La的含量比值有所减小。利用估算不同化合价离子数目比的量子力学模型估算了La0.6Sr0.1TexMnO3材料中Te3+离子的含量,发现各样品中Te3+离子的含量都小于1%。利用Rietveld精修对XRD衍射数据进行了拟合。发现晶胞体积V,Mn–O键长d,Mn–O–Mn键角Θ都没有明显的变化。磁性研究表明,样品的居里温度也没有明显的变化。所有这些分析结果表明,几乎所有的Te离子和一部分Mn离子在1473K的样品烧结过程中挥发了。
学位年度:2010
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