有机合成中氢解反应的研究

氢解反应是有机合成中的一个重要反应,通过脱卤氢解、脱苄氢解、开环氢解、脱硫氢解、重氮盐氢解、醛酮氢解等,广泛应用于有机合成.     

不定方程x^2＋y^2＋z^2=2（xy＋yz＋xz）的解及其性质

从方程自身的特征出发,研究解的特性,引入方程的同组解、邻解、奇解与非奇解、互质解的概念,得出方程最简单的解和互质解谱树图,导出一系列解的性质的结论,且可由方程的最简单的解和互质解谱树图求出方程全部解的结果。     

整合分数阶修正的等宽波动方程的所有单行波解的分类

利用多项式的完全判别法,构建了整合分数阶修正的等宽波动方程的所有单行波解的分类.基于所提出的方法,获得了许多新的精确解,这些解包括双曲函数解、三角函数解、有理函数解、隐式解和雅克比椭圆函数解.     

上、下解与拟上下解的存在性

利用上、下解与拟上下解方法讨论常微分方程问题时,文献均是假设上、下解与拟上下解是存在的,进而讨论方程的解.给出一阶常微分方程初值问题的上、下解与拟上下解的存在性定理,为利用上、下解与拟上下解方法讨论一阶常微分方程初值问题提供充分的依据.     

KdV-mKdV方程的新行波解

研究了KdV-mKdV方程的行波解求解的问题,利用双曲函数法和新的G展开法,获得了该方程的含有多个任意参数的新的行波解,分别为三角函数解、双曲函数解、有理函数解和指数函数解,扩大了该类方程的解的范围。     

Yu-Toda-Sasa-Fukuyama方程的对称、约化和精确解

利用经典李群法得到了YTSF方程的对称、约化,通过解约化方程得到了该方程的一些精确解,其中包括双曲函数解、三角函数解、有理函数解、Jacobi椭圆函数解等.     

Variant Boussinesq方程组的精确解

F-展开法是近年提出的求非线性偏微分方程的精确解的一种简单而有效的方法.本文运用改进的F-展开法寻求Variant Boussinesq方程组的行波解,得到了该方程组多种类型的精确解,包括Jacobi椭圆函数解、孤立波解、三角函数解和有理函数解.     

Linear Programming图解法建模研讨

对仅有两个变量的Linear Programming,通过图解法求最优解。建立了数学模型并求得了最优解。从图解法可以直观地看出,仅有两个变量的Linear Programming的解有唯一最优解、无穷多个最优解、无界解和无可行解四种情况．若其有最优解,则必定会在其顶点上得到;若在多个顶点上得到最优解,则其有无穷多个最优解。     

形变映射法构造非线性Boussinesq方程的行波解

利用变形映射法 ,建立Boussinesq方程与三次非线性Klein -Gordon(NKG)方程一类特殊类型解的代数变换关系。根据该关系以及NKG方程的已知解 ,获得Boussinesq方程系统丰富的显式精确行波解 ,包括孤波解、周期波解、雅可比椭圆函数解和其他精确解     

高考数学解答题的题型与解读

一、高考数学解答题的基本题型认真分析近几年各省市高考数学试题,虽略有差别,但总体上高考卷五至六个解答题的模式基本不变,分别为三角函数与平面向量型解答题、立体几何型解答题、概率型解答题、函数与不等式型解答题、解析几何型解答题、数列型解答题.这是高考数学的重头戏.这部分内容包含的知识容量大、解题方法多、综合能力要求高,它们突出了中学数学的主要思想和     

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!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.