拟线性抛物型方程在第三边值条件下的极大值原理

文章以线性抛物型方程的弱极值原理和强极值原理为主要工具,讨论了拟线性抛物型方程β（tu）=Δu＋（fx,t,u）解的泛函V（x,）t=g（u）ut＋h（u）和β（tu）=Δu＋（fu）解的含梯度泛函P（x,t,u,u）k=塄u2＋2Z（）tF（u）（F＇=）f,在第三边值条件下的极大值原理。     

基于泛函变分的求解振动方程的迭代方法

结合变分法与拉氏乘子法，构造含拉氏乘子的迭代泛函，由泛函极值条件确定拉氏乘子给出求解振动方程的迭代格式。通过算例说明了该方法实现的具体步骤，其结果同时表明这种方法对于求解振动方程既有效又简便。     

一类拟线性薛定谔方程的正解

考虑一类拟线性薛定谔方程的正解,由于该类方程所对应泛函不能定义在常用空间H1（RN）上并且嵌入是非紧的,这也导致了很难直接求解.因此利用变量变换在H1（RN）的径向空间上考虑方程的解,从而可以利用山路引理和极值原理证明所研究方程存在正解.     

力学拉格朗日函数的推广

前言 力学中最速降落线问题的提出,促成数学变分学的建立。而变分法又成为研究物理学各部门的有力工具。力学中首先利用泛函极值概念表述力学基本定律,建立了哈密顿原理或最小作用量原理,导出拉格朗日函数和方程。爱因斯坦把经典力学中相对原理推广为一切物理现象必须服从的相对性原理,结合光速不变性事实,建立了适用于高速运动的力学,并由引力场的最小作用原理导出引力场方程。德布罗意遵循最小作用量原理和费马原理相似思想,论     

略论物理学中积分形式的变分原理的应用及意义

略论物理学中积分形式的变分原理的应用及意义李淑侠１前言在物理学中，泛西取极值的问题被称为变分原理．变分原理还有等价的表述，即最小作用量原理；作用量取极小值。其变分为零．能描述轨道“优越性”的轨道泛函被称为作用量．最小作用量原理所考虑的作用量Ｓ是由整条...     

分部积分公式推广之研究

对分部积分作归纳推广,并应用到一些积分类型、级数类型和泛函极值类型中去,使这些问题演算得更加轻巧,特别是应用到级数类型,不仅找到了级数求和与改变收敛的新方法,而且顺便得到了分析上极有用的两个公式（马克劳林级数和泰勒级数）的新推导,应用到求泛函极值类型,顺便得到了分部积分各项与泛函极值的边界条件之间的联系,再通过工程实例说明泛函极值边界条件的分类办法.     

一类抛物方程的弱比较原理

研究了一类半线性热方程弱解的弱比较原理,所得到的结果推广了已有线性抛物方程的有关的极值理论.     

欧拉—拉格朗日方程的推广

变分法是处理泛函极值的一种数学方法,欧拉—拉格朗日方程是基于变分法得到的,该方程在除数学外的很多其他领域有着广泛的运用.如果能将欧拉—拉格朗日方程的应用范围进一步扩大,即条件减弱或者放松限制条件,就可以使已有的结论更完善.本文运用变分法,得到更普遍适用的欧拉—拉格朗日方程.     

椭圆型偏微分方程边值问题与变分问题的等价性

文章给出了流体稳定运动中椭圆型偏微分方程的一般边值问题,从两个方面证明了椭圆型方程的边值问题等价于一个泛函变分的极值问题。一方面证明函数类C0中使泛函E(H)达到极小函数H m是边值问题的解,另一方面证明若有一个函数H m满足边值问题,则H m一定是E(H)在C0中的极小函数。     

一类超线性p-Laplace方程基态解的存在性

本文讨论一类超线性p-Laplace方程。利用Ekeland变分原理,讨论f(x,u)在超线性的条件下,方程所对应的Euler-Lagrange泛函I满足引理的条件,从而得到泛函的Cerami序列,进一步证明此泛函的Cerami序列有界,最后证明有界的Cerami序列有强收敛的子列,且收敛于方程的一个基态解。     

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?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

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…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.