共查询到20条相似文献，搜索用时 593 毫秒
1.
首先研究如下类型的边值问题：y″=f（t,y,y′）（a〈t〈b）、py（a）-qy（b）=a,ry＇（a）-sy＇（b）=B的微分不等式与解的存在性，然后，利用所得的结果，研究二阶拟线性微分方程的边值问题{εy″=f（t,y）y＇＋g（t,y）、y（a）=y（b）,ry＇（a）-sy＇（b）=B的奇异摄动现象。 相似文献
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首先利用微分不等式研究如下类型的周期边值问题{y＇＇=f（t,y,y＇）,0〈t〈l y（0）=y（t）,y＇（0）=y＇（l）.的微分不等式与解的存在性,并在一定条件下把解延拓成为微分方程在无穷时间区N-Y-N期解,然后利用所得结果讨论奇异摄动现象． 相似文献
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研究如下形式的三阶微分方程的n点边值问题{y′′′=f（t,y,y′,y″）,a〈t〈b y（a）=A,y′（a）=B,h[y′（t1）,y′（t2）,…y′（tn-2）,y′（b）]=0的微分不等式与解的存在性,这里a〈t1〈t2〈…〈tn-2〈b.然后利用所得到的结果，研究带有正的小参数ε的n点边镇问题{εy′′′=f（t,y,y′,ε）y″＋g（t,y,y′,ε）,a〈t〈b y（a）=A,y′（a）=B,y′（b）-^N-2∑i=1piy′（ti）=c的奇异摄动，这里常数P1，P2，…，pn-2〉0． 相似文献
4.
研究在强稳定条件下的具有两个小参数的二阶微分方程的边值问题
{εy″=f（t,y,y′,ε,μ）,a〈t〈b
y（a,ε,μ）=A（ε,μ）,y（b,ε,μ）=B（ε,μ）
的奇异摄动现象． 相似文献
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研究带有转向点的奇摄动非线性边值问题{εy″=f（t,y,y,′ε,μ）（a〈t〈b）、y（a,ε,μ）=A（ε,μ）,y（b,ε,μ）=B（ε,μ） 的解的存在性与渐近性质，以及摄动解关于退化解的误差估计． 相似文献
6.
陈福松 《宁德师专学报(自然科学版)》2008,20(4):341-344
研究如下形式的三阶半线性微分方程的周期性边值问题{ y＇=f（t,y,y＇（,0〈t〈l y（0）=y（l）,y＇（0）=y＇（l）,y″（0）=y″（l）的微分不等式理论与解的存在性,并在（t,y,y’）是周期为l（y,y’看作是固定的）的周期函数的条件下,通过[0,l]上的解的周期延拓,得到周期解的存在定理． 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
9.
本文运用打靶法讨论二阶差分方程边值问题
｛△^2y（t-1）=f（t,y（t）,△y（t））,t∈{a＋1,…,b-1},
y（a）=A,y（b）=^n∑i=1aiy（§i）
解的存在性,其中f：{a＋1,…,b-1}×（-∞,＋∞）×（-∞,＋∞）→R连续,有界且满足Lipschitz条件,a,b∈Z,§i∈{a＋1,…,b-1},i=1,2,…,n,n≤b-a-1是一个固定的自然数。 相似文献
10.
张英 《雁北师范学院学报》2008,24(6)
运用Avery—Henderson锥上的不动点定理,讨论了时间模上的二阶非线性动力学方程3-点边值问题{y^△ （t）＋a（t）f（y（t））=O,t∈[t1,t3] T,y^△（t1）=0,y（t3）=βy（t2）至少有两个正解的存在性．其中T是一个时间模,0≤t1〈t2〈t3,0〈β〈1． 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