二阶非线性差分方程的振动性

考虑方程△(bn△un) ∑i=1^mainfi(un,△un)=0,n=0,1,...(1)的振动性，获得了其解振动的几个充分条件。     

二阶半线性迟滞差分方程的振动准则

利用文献[1]中构造序列的方法,研究了二阶半线性迟滞差分方程△(rn|△un|α-1△un)+Pn|un-1|α-1un-1=0,n=0,1,2…的振动性,得到了该方程的一些新的振动准则;其中实数α≥1,l为非负整数,序列{rn}∞n=0为正实数序列,序列{pn}∞n=0为非负实数序列且存在一正子序列,并且Rn=n-1∑i=0 ri-1/α→∞(n→∞).     

一类时滞差分方程解的振动性和渐进性

讨论了一类二阶时滞差分方程△(αn(△Yn)σ)+qnf(yrη△1)g(△yn)=0解的振动性和渐进性.借助于方程系数的讨论,通过构造函数序列,用反证法给出当σ=奇数/奇数时方程解振动的充分条件和当σ=偶数/奇数时方程解的渐进性质.     

正项级数比值判别法的极限形式的推广

针对比值判别法的极限形limx→∞un+1/un=q=1的不定情形,对比值判别法的极限形式进行推广,通过limx→∞(un/un+1)n=r可判定当比值判别法的极限形式中limx→∞(un+1/un)=q=1时,一些正项级数的敛散性.     

二阶超线性差分方程的有界振动(英文)

讨论了一类超线性差分方程△2 xn =∑mi=1pi(n)xαin-ki　　 (αi >1) ( )的振动性 ,获得了有界振动的充分条件     

具多滞量脉冲时滞差分方程解的振动性与非振动性

讨论具有多个滞量的脉冲时滞差分方程△x(n) + ∑mi=1pi(n)x(n-li) =0 ,n≥ 0 ,n≠nkx(nk + 1) -x(nk) =bkx(nk) ,k=1,2 ,3,…给出了方程解的振动与非振动的充分条件 ,有关振动性的结论同样适用于不带脉冲扰动条件的差分方程     

一类非线性中立型差分方程的振动性和非振动性

考虑下列非线性中立型差分方程 △(x_n-p_nx_(n-k))+f(n,x_(n-1))=0, n=0,1,2…… 建立了当P_n-1振动且通常的发散条件sum from n=0 to ∝(f(n,c))=∝对c>0不成立时,上述方程所有解振动和非振动的解存在的几个新的充分性条件。     

Schrdinger方程的一个高精度差分格式

用含参数的差分方程逼近微分方程的方法 ,构造了Schr dinger方程的一个三层高精度隐式差分格式 :112τ(32 un + 1j+ 1-2unj+ 1+ 12 un-1j+ 1) + 56τ(32 un+ 1j -2unj+ 12 un -1j ) + 112τ(32 un + 1j-1-2unj-1+ 12un-1j-1) =iun + 1j+ 1-2un + 1j +un + 1j-1h2 ,其截断误差阶可达到O (τ2 +h4) 并用Miller定理证明了其稳定性 ,数值例子表明该格式是有效的     

波动图象应用题解导引

本文就应用波动图象,判定质点的振动方向,分析波动在传播过程中的隐含条件,谈波动图象的应用.一、判定质点振动方向由波的图象和波的传播方向确定某时刻质点振动方向的方法一般有两种:(1)微平移法——沿波的方向平移波形图.即平移微小量△x=v△t,此时的波形为经△t时刻的波形,看该质点此时的位置、确定振动方向.     

具多滞量脉冲时滞差分方程解的振动性与非振动性

讨论具有多个滞量的脉冲时滞差分方程{△x（n） ∑i=1^mpi(n)x(n-li)=0,n≥0,n≠nk x（nk 1)-x(nk)=bkx(nk),k=1,2,3,…给出了方程解的振动与非振动的充分条件,有关振动性的结论同样适用于不带脉冲扰动条件的差分方程。     

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.