共查询到20条相似文献，搜索用时 62 毫秒
1.
研究四阶奇异两参数常微分方程周期边值问题{u^（4）（t）-βu″（t）＋au（t）=f（t,u）（T（t）））,t∈[0,1]u^（i）（0）=u^（i）（1）,i=0,1,2,3}正解的存在性和多重性．当允许f（t,u）在u=0在u=c（c〉0）处同时奇异时,可用锥上的不动点指数理论证明该问题多个正解的存在性． 相似文献
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王彩华 《赤峰学院学报(自然科学版)》2010,26(3):14-16
本文利用锥上的不动点定理研究了下列奇异非线性二阶三点边值方程组{-u″=f（t,v）, t∈（0,1） -v″=g（t,u）,t∈（0,1） u′（0）=v′（0）=0,u（1）=αu′（η）,v（1）=αv′（η）其中η∈（0,1）,α〈0在某些较弱条件下正解的存在性． 相似文献
3.
郭建敏 《雁北师范学院学报》2008,24(1)
利用关于锥拉伸锥压缩的Krasnoselskii不动点定理,讨论了非线性奇异三阶两点边值问题{u^m（t）＋λa（t）f（u（t））=0,0〈t〈1 u（1）=u′（1）=u″（0）=0正解的存在性,得到上述边值问题至少存在两个正解的λ的区间,其中λ是一个正常数。 相似文献
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文章借助锥不动点定理证明了带混合两点边值条件的二阶微分方程（u^n＋m^2u＋f（t,u）=0, 0〈t〈1 au（0）-βu′（0）=0,γu（1）＋ δu′（1）=0） 正解的存在性。 相似文献
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孙艳梅 《商丘师范学院学报》2008,24(6):23-27
用不动点定理,研究半无穷区间边值问题{u″＋a（t）f（u）＋b（t）g（u）=0,0〈t〈∞,u（0）=∞,u′（∞）=0的多个正解的存在性． 相似文献
6.
薛妮娜 《山东教育学院学报》2007,22(1):105-109
本文利用Krasnosel′skiis不动点定理讨论了下面的三阶两点奇异边值问题u(t) λa(t)f(t,u(t))=0,00为参数。 相似文献
7.
何希萍 《甘肃广播电视大学学报》2013,(3):1-5
利用不动点定理研究了一类三阶边值问题,u^m（t）=＋a（t）f（u（t））=0,0〈t〈1,u（0）=0,u（1）-au（η）=b正解的存在性及不存在性。在适当的假设下,证明了当f为超线性时,此问题对于足够小的b有一个正解,对于足够大的b没有正解。当f为次线性时,此问题对于所有b〉0有一个正解。 相似文献
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讨论Banach空间中微分方程u（ 4）（t）-2ku＂（t）＋k2“（t）=λf（t,u（t））在边值条件u＇（o）=u＇（1）=u（＂＇）（0）=u（＂＇）（1）=θ下正解的存在性.通过构造一个特殊的锥,证明了上述边值问题正解的存在性和不存在性,最后给出一个例子说明主要结果. 相似文献
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讨论带有延滞项的奇异三点边值问题:u″(t)+f(t,u(t-τ))=0,t∈(0,1)\τu(t)=η(t),t∈u(1)=βu(α)(1)正解的存在性,其中f变号且可能在t=0,t=1,u=0处奇异,文章的最后给出了这个定理的具体应用. 相似文献
10.
运用格林函数性质和不动点指数理论,研究了非线性微分方程u″（t）＋a（t）f（t,u（t））=0四点边值问题正解的存在性. 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
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. 相似文献
12.
Richard Denner 《海外英语》2007,(4):14-15
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. 相似文献
13.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 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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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 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