二次奇摄动问题解的渐近估计

研究了二次奇摄动问题εy″=p(t,y)y′2 +g(t,y) ,0 相似文献   

修正的Kurramoto—Sivashinsky方程的周期行波分支

本文研究具有色散项μu_(xxx)的修正的Kunamoto—Sivashnsky(以下简称mks)方程,该方程具有重要的物理应用价值。本文证明了对任意波速c>0,存在μ=2~(1/2)c+μ_2ε~2+O(ε~3),0<ε<<1,使得mks方程有一个周期行波解。     

气体动力学方程组整体解的存在性

一维均熵多方气体动力学方程组v_t+u_x=0,u_t+[p(v))_x=0,是准线性双曲型守恒律组的典型方程,这里P(v)=K~2v~(-γ),T. Nishida就γ=1的情形解决了初值问题整体解的存在性,把它推广到-1<γ≤0的情形,在气体动力学中,重要的是1<γ<3的情形。T.Nishida与J.A.Smoller证明了对给定的初值,存在ε_0>0充分小,使当1<γ<1+2ε_0时,初值问题存在整体解,本文推广文[4]的结果,解除对ε_0>0充分小的限制,允许1<γ≤3。     

一类奇摄动无穷边值问题解的渐近性质

本文讨论二阶非线性边值问题εy″=f(t,y,y′),0相似文献   

扰动KdV方程解的先验估计

对于带微扰的KdV方程u_t+6uu_x+u_xx=εR(u),(ε＞0),在初值u₀(x)∈C∞(-∞,+∞),当|x|→∞时指数衰减的条件下,分别构造出带两种不同扰动项的KdV方程的扰动孤立波解满足的能量关系式,并运用能量分析方法对扰动的孤立波解进行先验估计,得到如下结论：(1)R(u)=δ(εt)u, δ(s)∈C［0,+∞),δ(0)=0,时,解在-∞＜x＜+∞,0≤εt≤T内一致有界;(2)R(u)=-Δ(εt)u_xxx,Δ(0)=0,Δ(s)∈C¹［0,+∞), 解在-∞＜x＜+∞,0≤εt≤T,0≤ε≤ε₁内一致有界。     

三维空间中半线性波方程整体解的渐近性

研究三维空间中半线性波方程utt-△u=εf(u ,ε) ,　t >0 ,u(0 ,x ,ε) =u0 (x ,ε) ,ut(0 ,x ,ε) =u1 (x ,ε) ,(其中 x∈R3 ,u是一个实值未知函数 ,△ =∑3i =1 2 x2 i,ε充分小且 0 <｜ε｜≤ε0 1,)整体解的渐近性 ,得到了在C2 空间中时间T =∞时形式近似解的合理性及适定性 .这一结果描述了形式整体解的渐近行为     

半线性奇摄动边值问题的定性分析

本文在相平面上对半线性奇摄动边值问题 s(d~2x)/(dt~2)=h(x),x(0)=A=A,x(1)=B,0<ε<<1的解的存在性和个数以及极限解进行了定性分析,并对时间进行了渐近估计,从而发展了[1]和[2]中的结果     

奇摄动非线性系统的边界层与内过渡层性质

本文对非线性向量边值问题εy″=f(x,y,y′),-10,在适当的假设下,证明其解的一些分量呈边界层性态,而另一些分量呈内单调过渡层性态。     

扩散占优的2&#215;2双曲平衡律奇异松弛极限及其应用

研究一般扩散占优的2&#215;2双曲平衡律系统奇异松弛极限，用补偿紧性方法，在松弛时间τ比扩散系数ε趋于零快时，即τ=o（ε），ε→0时，得到其解的整体存在性一般框架：如果上述系统的解存在对ε一致的先验L∞估计，则其解序列收敛于上述系统的对应平衡状态解。并将这一框架应用于一些具有非齐次项和松弛项的重要非线性系统，如有非齐次项和松弛项的二次流、LeRoux系统、非线性弹性系统和交通扩展流等。     

非线性微分方程组初边值问题的奇摄动

本文利用微分不等式理论研究了非线性微分方程组初边值问题:εy′=f(t,y,ε),00为小参数,y、f、A和B为n推向量函数。在适当的条件下证明了解的存在,求得解及其任意阶的一致有效渐近展开式,并对余项做出了估计。     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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