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研究了一类二阶非线性泛函微分方程解的振动性质.在一定条件下,应用分类讨论和分析的方法,建立了一个新的振动性定理,推广和改进了已知的结果. 相似文献
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非均匀弦自由振动的求解 总被引：1，自引：0，他引：1
利用分离变量法得到了由两段密度不同的均匀弦所组成的非均匀弦自由振动问题的一般解表达式,讨论了满足特定条件的解析解,进而提出了求解这类非均匀弦自由振动问题的一般思路和方法. 相似文献
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利用分析的方法和不动点原理,研究了一类不稳定的二阶非线性中立型差分方程,给出了该类方程有界解振动的一个充要条件及非振动解趋向于零的一个充分条件,对已有文献中某些结果进行了推广和改进. 相似文献
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李龙图 《湘潭师范学院学报(社会科学版)》1990,(6)
本文讨论一阶中立型线性微分差分方程其中,给出了方程(1)非振动解存在的类型,得到了方程(1)存在A_K型非振动解的充要条件和存在A_o型非振动解的充分条件. 相似文献
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讨论了一类脉冲中立型时滞抛物偏微分方程组的振动性质,运用脉冲微分不等式和积分的方法,获得了其所有解振动的一些充分条件. 相似文献
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《常熟理工学院学报》2015,(4)
利用分析的方法和不动点原理,研究了一类不稳定的二阶多时滞中立型差分方程,给出了该类方程有界解振动的一个充分条件及非振动解趋向于常数的充分或充要条件,并对已有文献中某些结果进行了推广和改进. 相似文献
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讨论方程的振动性,其中б为两正奇数之比,建立了此方程所有解振动的一个充分条件及所有有界解振动的一个充分条件. 相似文献
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二阶非线性脉冲微分方程的振动性 总被引：2，自引：0，他引：2
吴红叶 《广东技术师范学院学报》2005,(6):79-82
利用R iccati变换、函数平均法和辅助函数,讨论了一类带脉冲二阶非线性时脉冲微分方程解的振动性,并得到了这类方程所有解振动的一组充分条件. 相似文献
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本文研究了一类具有连续偏差变元带中立项的双曲偏泛函微分方程解的H-振动性,给出了判别解H-振动的充分条件.这里H是Rm中单位向量. 相似文献
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讨论了一类具有连续偏差变元的二阶中立型方程,得到了该类方程一切解振动和一切可微解导数振动的充分条件,所得结果推广了以往的相应结果. 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