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针对振动摩擦焊接机在焊接过程中的外激振力幅值确定较为困难的问题,对振动摩擦焊接机中的电磁振动原理、电磁力计算、电磁力仿真分析等方面进行研究,对静态进程模式下正余弦信号与电磁力之间关系进行归纳,提出一种基于MATLAB的电磁振动仿真分析方法。结合电磁振动学和牛顿运动学方法综合建立简化的电磁力理论推导,借用MATLAB分析正弦和余弦对电磁力的影响规律,利用振动摩擦焊接试验台对所建立的电磁力理论推导方法进行实验验证。研究结果表明,当输入正弦信号,时间为0.002 5s时,电磁力最大值为400N;当输入余弦信号,时间为0.002 6s时,电磁力最大值为556.080 0N,从而为振动摩擦焊接机的外激振力及其频率确定提供了依据。 相似文献
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应用麦克斯韦理论和狭义相对论的基本原理,对运动方向平行于分界面的匀速运动导体-介质周期结构进行了研究,分析推导了相关的电磁散射和电磁力表达式,并通过数值计算绘制了电磁力随有关参量变化的曲线.这些结果可以应用于一大类与电磁相互作用有关的连续运动部件,如微电子机械系统中的传感器和执行器. 相似文献
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研究目的：对一种两自由度的压电-电磁复合能量收集器进行发电性能研究。创新要点：建立了一种两自由度压电-电磁复合能量收集器发电性能的数学模型,该数学模型可以评估两自由度压电-电磁复合能量收集器中压电元件、电磁元件以及系统总输出功率。研究方法：对一种两自由度的压电-电磁复合能量收集器进行数学建模,并实验验证数学模型的正确性。基于实验测试得到的系统参数值,理论研究压电元件和电磁元件的机电耦合系数对不同能量收集器发电性能的影响关系,并对几种能量收集器的发电能力进行对比分析。重要结论：对于非强耦合（弱或中间耦合）的两自由度机电转换器,复合能量收集器（压电＋电磁）具有比单一能量收集器（压电或电磁）更高的发电能力。 相似文献
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研究目的:对一种两自由度的压电-电磁复合能量收集器进行发电性能研究。创新要点:建立了一种两自由度压电-电磁复合能量收集器发电性能的数学模型,该数学模型可以评估两自由度压电-电磁复合能量收集器中压电元件、电磁元件以及系统总输出功率。研究方法:对一种两自由度的压电-电磁复合能量收集器进行数学建模,并实验验证数学模型的正确性。基于实验测试得到的系统参数值,理论研究压电元件和电磁元件的机电耦合系数对不同能量收集器发电性能的影响关系,并对几种能量收集器的发电能力进行对比分析。重要结论:对于非强耦合(弱或中间耦合)的两自由度机电转换器,复合能量收集器(压电+电磁)具有比单一能量收集器(压电或电磁)更高的发电能力。 相似文献
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介绍了金刚石在合成过程中的液压系统以及液压系统的工作时序，提出了以STD工控机为控制核心的控制系统；通过工控机对整个系统进行检测，由触发板驱动SCR，使对合成块的输出电压维持恒定；利用触发板驱动SCR，使SCR的输出电压能调节副泵的转速，使之能够满足金刚石在保压阶段对压力的要求；在系统设计的最后，对活塞和锤头之间的绝缘性进行了硬件设计。 相似文献
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针对两个传统电磁阻尼演示实验的存在的问题(现象不明显、成功率低),改变思路,设计新的一个实验方案,效果极佳且同时可以演示电磁驱动现象。 相似文献
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在物理教学课堂中创设多元实验情境，是落实学生核心素养的重要途径.本文以“涡流、电磁阻尼和电磁驱动”教学设计为例，详细阐述了如何落实核心素养的整个教学思路和设计意图，并展示了课程实施的详细过程. 相似文献
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不平衡电磁力是影响大型水轮发电机组安全、稳定运行的重要因素之一 .对五强溪 4 #机组的不平衡电磁力及电磁刚度进行了计算 ,解决了工程上的实际问题 相似文献
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针对无线通信系统中的电磁与微波技术,提出将教学和实验实践划分为从内到外五个层次,包括:电磁传播层、电磁散射层、天线层、射频电路层、系统级参数层。对这些分层所包含的电磁与微波技术的基本概念、理论、实验实践进行了总结,给出了分层课程设计和内容规划。提出按年级进行分层培养的方案,并设计了包含基础课程类、仿真实践类、测量实践类各栏目的微波学堂网(wbxt.buaa.edu.cn)。 相似文献
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对传统金属管式楞次定律演示器提出两种改进方案,自制两套实验器材,可以方便地演示涡流、电磁阻尼、电磁驱动等多种电磁感应现象,实验效果直观明显,实验功能更加齐全. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献