一类带非线性源的拟线性抛物方程解的熄灭问题

研究了形如ut=Δpu+λ|u|q-2u的拟线性抛物方程在RN(N≥2)中有界空间上的解的熄灭问题,利用上下解方法得到两类在有限时间内解熄灭的结果.     

拟线性抛物方程的熄灭问题

本文对拟线性抛物方程的混合问题定义了上、下解,推出比较定理,从而为这类方程判断解的熄灭与否提供了一种可行方法.     

半线性抛物型方程的熄灭问题

本文讨论半线性抛物型方程u_t-Lu=εf(u)的熄灭问题,并给出方程的解在有限时间内发生熄灭和全局存在的条件.     

一类非线性抛物型方程解的性质

Chia-ven Pao在大量文章中利用上下解的方法研究拟线性抛物型方程及初始边界条件的解的性质。但在他的研究的方程中,系数都是与u和u_x无关的函数。本文想讨论关于如下问题的解的性质     

带时滞的退化半线性抛物方程的熄灭

考虑带时滞的退化半线性抛物方程的熄灭问题．利用正则化方法和上下解技巧,我们得到了上述问题经典解的存在惟一性,同时还证明了存在一个临界长度α＊使得上述问题的解α〈α＊时整体存在,而当α〉α＊时在有限时间内熄灭．进而我们还得到关于临界长度α＊的一个简单估计．     

一类伪抛物方程的非线性扰动

非线性伪抛物方程和一些重要的物理过程有着密切的关系,研究了一类伪抛物方程△（u＋δu/δt）-δu/δt-f（x,tu）=F（x,t,u,δu/δxi）初边值问题的非线性扰动问题。首先在Hilbert空间中建立了强制不等式,利用同胚方法和抽象的反函数定理,得到了半线性伪抛物方程初边值问题解的存在性和惟一性定理。在此基础上,讨论了对应的非线性扰动。通过构造相应的紧算子,利用同伦对算子进行估计并利用Schauder不动点定理,给出了非线性扰动问题解的存在定理。     

拟线性抛物型方程边值问题时间周期解

研究一类拟线性抛物型方程的边值问题。首先引入时间周期的H lder连续函数空间CT2 σ(Ω)和函数,在已知函数的某些假设条件下,利用上下解方法和Leray-Schauder不动点定理证明了边值问题有满足j(x)≤u(x,t)≤j(x)的时间周期解u(x,t)∈C2T σ(Ω)。由函数F的定义推断出所研究的边值问题时间周期解的存在性。     

二阶拟线性抛物型方程极大值原理的一个简单应用

应用拟线性抛物型方程βt(u)=Δu+f(x,t,u)解的泛函V(x,t)=g(u)ut+h(u)在第一边值问题中极大值原理来研究解的爆破的问题.     

变系数多孔介质单相流方程弱解的存在性

主要研究变系数多孔介质单相流方程弱解的存在性。首先建立与原方程等价的拟抛物方程的Dirichlet问题,然后利用粘性法构造其逼近方程,并通过上下解方法证明拟抛物方程粘性解的存在性,最后利用能量方法得到拟抛物方程的粘性解是其弱解,证明了变系数多孔介质单相流方程弱解的存在性。     

非线性拟抛物方程解的熄灭

本文采用特征函数法与积分估计法研究两类非线性拟抛物方程的初边值问题解的熄灭问题,分别给出了其古典解与广义解熄灭的两种较为广泛的充分条件.     

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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