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1.
本文研究微分积分方程奇摄动边值问题(t,y,J,ε);y(0,ε)=y(1,ε)=0;0<ε《1;其中J=(t,ε)+(t,s,y(s,ε),ε)ds,α=1或t。首先利用边界层函数法构造了这个问题解关于的形成渐近展开,然后证明该问题解的局部存在唯一性以及所构造渐近级数的一致有效性。  相似文献   

2.
研究如下形式的三阶非线性微分方程的周期性边值 {y′″=f(t,y,y′,y″),a〈t〈b, y(a)=y(b),y′(a)=y′(b),y″(a)=y″(b). 的微分不等式与解的存在性,并在上下解及Nagumo条件下,得到了解的存在性定理.  相似文献   

3.
摘要:利用Lery—Schauder不动点定理讨论了当m是一切自然数,G是一般的增算子时二阶边值问题((G(y))’+p(t)y^m)’+q(t)f(t,y)=p’y^m,0〈t〈1,y(0)=0,y(1)=b0〉0解的存在性.  相似文献   

4.
研究含慢变量非线性方程组初值问题:x‘=g(t,x,y), εy〃=h(t,x,y, μy’)当ε=O(μ^2)时的初始层性质,通过压缩映射证明了摄动解的存在,得到了解的一致有效的渐近展开式。  相似文献   

5.
二次奇摄动问题解的渐近估计   总被引:5,自引:0,他引:5  
研究了二次奇摄动问题εy″=p(t,y)y′2 +g(t,y) ,0 相似文献   

6.
利用匹配渐近展开法,讨论了一类二阶非线性奇摄动问题εy″+yy'+xy+y^2=0,x∈(0,1),y(0)=α,y(1)=β,通过匹配方程的内层解、外部解及边界层解,得出解的层性态与边界条件的关系,并给出了解的渐近表示.  相似文献   

7.
考虑如下Caputo分数阶差分方程△C^v y(t)=-f(t+v-1,y(t+v-1))在非局部条件y(v-3)=φ(y),△y(v+6)=ψ(y),△^2y(v-3)=λ(y)下的边值问题(BVP),其中t∈[0,b],f:[v-2,v-1,…,v+b]Nv-2×R→R,f为连续函数,φ,ψ,λ∈C([v-3,v+b])→R,2〈v≤3。利用Banach压缩映射定理和Brouwer不动点定理得到此边值问题解存在的充分条件。  相似文献   

8.
先从理论上研究了超二次奇摄动Robin问题εy“=h(t,y)f(y’),t∈[0,L],y(0,ε)-py'(0,ε)=A(ε),y(L,ε) qy'(L,ε)=B(ε),然后给出了这一问题解的估计,并证明了解的渐近性.最后,将这一理论用于解决液体遇竖直固器壁平面时,表面高度的问题.  相似文献   

9.
本文研究奇摄动积分微分方程的Robin边值问题 εy″=f(t,Ty,y,y′,ε), α(ε)y(0)—b(ε)y′(0)=A(ε),c(ε)y(1)+d(ε)y′(1)=B(ε),其中T是定义在C[0,1]上的一个积分算子。文中用微分不等式方法证明了解的存在性,构造出解的渐近展式并给出了余项的一致有效估计.最后把所得结果用于研究奇摄动四阶边值问题. εx~((4))=f(t,x,x″,x,ε), x(0)=φ(ε),x(1)=φ(ε), α(ε)x″(0)—b(ε)x(0)= A(ε),c(ε)x″(1)+d(ε)x(1)=B(ε).  相似文献   

10.
利用稳定性理论,分析了非线性非自治奇摄动方程εy″=y-ty′-(y′)^4,t∈(-1,1) Robin问题边界值对解的渐近性态的影响,得出了边界层存在的位置与渐近解存在的条件.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

19.
20.
<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has  相似文献   

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