利用V函数研究非线性系统解的稳定性

该文用李雅普诺夫(Liapunov)的第二方法分析了一类三阶非线性微分系统(x) ψ(x)f((x)) g((x)) h(x)=0(1)零解的稳定性.在常系数线性系统的李雅普诺夫函数的基础上,通过变换找到该系统的等价线性系统,采用线性类比的方法构造出合适的李雅普诺夫函数,从而得出了这个系统的零解是渐近稳定的一组充分条件.     

基于李雅普诺夫函数的零解稳定性

考虑二阶线性系统的零解的稳定性,本文导出了二阶线性系统的李雅普诺夫函数的构造,讨论对于选取不同的李雅普诺夫函数对判断系统的零解稳定性结论的影响,并得到对于不同的李雅普诺夫函数在判断二阶线性系统的零解的稳定性结论上是一致的。     

一类四阶非线性系统零解的稳定性

该文在四阶常系数线性系统李雅普诺夫函数的基础上,运用"线性类比法"构造出一类四阶非线性系统的李雅普诺夫函数,并得出该系统的零解稳定性的一个充分条件.     

一类非线性自治系统的稳定性

在线性系统李雅普诺夫函数的基础上,运用"类比法"讨论了一类四阶非线性系统李雅普诺夫函数的构造,并给出了该系统平凡解稳定的充分条件.     

一类三阶非线性系统的全局渐近稳定性

本文利用能量度量算法构造了三阶非线性系统(x...) a(x¨) b(x.) f(x)＝0(其中f(0)＝0)的李雅普诺夫函数,从而研究了它零解的全局渐近稳定性.     

Lyapunov函数的构造及应用

微分方程解的稳定性研究中最为常用的是李雅普诺夫第二法(直接法),利用这种方法研究系统的解的稳定性,其关键就是构造李雅普诺夫函数,即V函数.本文目的在于分析、总结系统稳定性的李雅普诺夫第二法的相关理论,以及如何借助李雅普诺夫函数来判断系统的稳定性.在Lotka-Voltera模型和流行病模型(SIR模型和SI模型)中,通过构造李雅普诺夫函数(一个与ln有关的函数),并借助李雅普诺夫函数及导数的符号特征,直接判断系统模型在平衡状态下的稳定性.     

一类三阶非线性系统的零解稳定性

利用类比法构造了一类三阶非线性系统的李雅普诺夫函数,得出了该系统零解稳定的充分条件,解决了相当广泛的一类三阶非线性系统的零解稳定性问题。     

一类四阶非线性系统的全局渐近稳定性

运用构造李雅普诺夫函数的方法,研究了一类四阶非线性系统的全局渐近稳定性,给出了该系统零解全局渐近稳定的充分条件。     

一类三阶非线性系统的李雅普诺夫函数的构造

本文用能量度量算法构造了一类三阶非线性系统的李雅普诺夫函数,从而研究了它们零解的全局渐近稳定性．     

一类五阶线性系统李雅普诺夫函数的构造

本文首先导出五维 数线性系统的李雅普诺夫函数公式，并在此基础上，分析一类五阶线性系统的李雅普若夫函数的构造。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

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?     

只要努力,不要后悔

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.     

浅谈移民问题

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.     

Sister Carrie, an Adherent of Desires

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.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

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.