含双参数边界条件的二阶三点边值问题解的存在性

运用Schauder不动点定理及上下解方法研究一类带有双参数边界条件的二阶三点边值问题{u″(t)+f(t,u)=0,t∈(0,1),u(0)-au(η)=λ_1,u(1)-bu(η)=λ_2解的存在性和不存在性,分别获得了使该问题存在解、存在正解、无解时λ_1,λ_2的取值区间.     

奇摄动Volterra型积分微分方程非线性边值问题的渐近估计

利用上下解方法给出了形如：δu″=f(t,u,Tu，ε)，g(u(0)，u(1))=0，h(u(0),u(1),u′(0)，u′(1))=0的边值问题解的存在性和渐近估计．     

推广的反应扩散方程的不变集和精确解

利用屈长征,Estevez提出的推广的不变集S_1={u:u_x=(1/x)F(u) зF(u)[exp(n-1)~n∫(1/F(z))dz]}求推广的反应扩散方程u_x=A(u)u_(xx) B(u)u_x~2 C(u)u_x D(u)的精确解,给出了推广的方程的一些特殊解,丰富了推广的方程的解.     

非齐次A—调和型方程很弱解的正则性

讨论了Rn(n≥3)中有界区域Ω上二阶非齐次拟线性椭圆型方程-divA(x,u)=B(x,u).当A(x,u)满足控制增长条件和单调不等式,B(x,u)满足控制增长条件|B(x,u)|≤C＇|u|P-1时,其很弱解u(x)∈W1,rloc(Ω)的正则性,其中max{1,p-1}＜r＜p,p为自然的Sobolev空间指数.文中采用Hodge分解的方法建立试验函数,借助Hlder不等式、Poincaré不等式及Young不等式对方程的很弱解得到了逆Hlder不等式,从而改进了其很弱解偏微商的可积性,使其成为经典意义下的弱解.     

一类非线性反应扩散方程解的Blow-up问题

利用极值原理研究一类具有混合边界条件的反应扩散方程ut= (a(u) u) +f (u) g(x) ,　　在 D× (0 ,T)内 ,u =0 ,在Γ1 × (0 ,T)上 , u n=0 ,　在Γ2 × (0 ,T)上 ;Γ1 ∪Γ2 = D,u(x,0 ) =u0 (x)≥ 0 , 0 ,　　　　在 D 内 .解的 Blow- up问题 ,给出了整体解不存在的一个定理 ,并得到了 Blow- up时间 T* 的上界 .     

一类二阶微分方程三点边值问题对称解的存在性

讨论了边值问题-un=w(t)f(t,u(t)),u(1)u'(0)-u'(1)=u(1/2).当w(t),f(t,u)满足适当的条件时,根据Leggett-WilJiams三解定理,得到了这类边值问题三解存在的充分条件,改进了相关文献的结论.     

(2+1)维拟线性热方程的不变集和精确解

目的研究带有反应项的(2 1)拟线性热方程ut=A(u)(uxx Nx-1ux) B(u)(uyy N-1yuy) C(u)u2x D(u)u2y Q(u)的精确解问题。方法运用推广的不变集E0={u:ux=vxF(u),uy=vyF(u)}求(2 1)维拟线性热方程的精确解。结果给出(2 1)维拟线性热方程的一些特殊解。结论此方法是(1 1)维拟线性热方程的推广。     

一类半线性热方程耦合系统的整体解

研究一类半线性热方程耦合系统带Dirichlet边界条件的问题 ,ut =vα1 uα2 (△u+u) ,　vt=uβ1 vβ2 (△v+v) ,　u =v Ω =0 ,u(x,0 ) =u0 (x) ,　v(x ,0 ) =v0 (x) (x∈Ω ,t>0 ) ,用正则化和上下解方法证明了该系统解的局部存在性 ,同时讨论了整体解的存在性 .     

带形区域上半线性椭圆方程的L~p分歧问题

本文证明了带形区域Ω上的半线性椭圆型方程λ△u(z)+u(z)=f(z,u),u(z)∈H_0~1(Ω),λ<0 (*)非平凡解的存在性及L~p分歧结果:当p∈[1,+∞)时,(0,0)为方程(*)在L′(Ω)中的分歧解;当p=+∞时,方程(*)在O处不发生L′分歧现象。     

四阶二点边值问题解的存在性

文章研究了u(4)(t)=f(t,u,u′,u″,u)t∈[0,1]u(0)=u′(0)=u″(1)=u(1)=0解的存在性问题.其中f∶[0,1]×R4→R连续,我们得到了至少存在一个解.     

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     

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

正~~     

Brief Introduction to “Journal of Jilin University( Science Edition) ”

<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