共查询到20条相似文献，搜索用时 203 毫秒
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利用D'Alembert-Lagrange微分变分原理和等时变分,推出了速度空间和加速度空间的微分变分原理,在坐标空间微分变分原理的基础上,建立了坐标空间的三种基本动力学方程形式,实现了微分变分原理的统一.举例说明应用. 相似文献
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为了进一步寻求动力学系统的守恒律,文章基于微分变分原理研究相空间中非完整力学系统的守恒律.首先从非保守系统的Hamilton原理出发,建立了相空间中非完整非保守系统的微分变分原理;其次,通过引进广义变分,给出了此微分变分原理在无限小变换下的不变性条件;最后,导出了相空间中非完整非保守力学系统的守恒律.文末举例说明结果的应用. 相似文献
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线性互补问题的解与变分不等式问题的解是等价的.基于变分不等式H-S定理给出了一般线性互补问题解的存在性定理.并证明了当矩阵M为对角占优矩阵时,对于可行的线性互补问题解是存在的. 相似文献
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El-Nabulsi在研究非保守系统的动力学建模时,提出了三种类分数阶变分方法,即：基于Riemann-Liouville分数阶积分的变分问题,基于按指数律拓展的分数阶积分的变分问题和基于按周期函数律拓展的分数阶积分的变分问题。将上述三种El-Nabulsi动力学模型拓展到Birkhoff系统,建立了El-Nabulsi-Pfaff变分问题,导出了El-Nabulsi-Pfaff-Birkhoff-d’Alembert原理和El-Nabulsi-Birkhoff方程。文末,举例说明结果的应用。 相似文献
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何时剑 《荆门职业技术学院学报》2005,20(6):18-20
给出了由声场的微分方程及边界条件导出的变分原理、广义变分原理以及由变分原理导出的有限元公式．通过对三个有代表意义的一维声场试验数据的比较分析，验证了上述变分原理及有限元公式的正确性． 相似文献
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将单调F-互补问题转化成单调F-变分不等式问题,利用解强单调F-变分不等式作为子问题,构造了一种不动点迭代算法,并证明了算法的收敛性. 相似文献
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变分原理在《结构化学》获《物质结构》中是很重要的内容，但在部分教材中介绍的不够完整。本文用实例说明选择试探变分函数不仅要符合品优条件，还要与所考虑体系有相同的边界条件。 相似文献
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任晓 《涪陵师范学院学报》2005,21(5):53-55
本文介绍了自反Banach空间中一类非线性混合似变分不等式，利用极大极小不等式和辅助变分原理技术，给出了这类非线性混合似变分不等式解的存在性与唯一性的新证法。 相似文献
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陈开勋 《临沂师范学院学报》2010,32(3):55-61
对于凸多面锥上的广义线性互补问题,借助二次规划问题将其等价地转化为一个仿射变分不等式问题,然后借助变分不等式问题的误差界讨论,给出了凸多面锥上的广义线性互补问题的绝对误差界估计． 相似文献
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在自反的Banach空间中,借助辅助原理,利用FKKM定理,研究了一类随机双线性型变分不等式随机解的存在性和唯一性.把一般的双线性型变分不等式问题经过随机化方法推广成随机双线性型变分不等式问题,所得的结果为近期一些工作的推广和发展. 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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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 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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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 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