时标上一类具有多时滞的中立型动力方程的振动性

考虑时标上具有多时滞中立型动力方程(x(t)-p(t)x(t-τ(t)))~Δ+m∑i=1q_i(t)f_i(x(t-σ_i))=0的振动性,获得了该方程振动解存在的充分条件.     

高阶非线性中立型方程的振动定理

研究了一类具有连续分布滞量的高阶非线性中立型方程a(t)ψ(x(t))[x(t) ∑mi=1ci(t)x(τi(t))](n-1)′ ∫baf(t,ξ,x(g(t,ξ)))dσ(ξ)=0解的振动性,运用数学分析方法和技巧及方程各阶导数的符号关系,在2种不同情形下得到了该类方程新的振动准则.     

时间轴上非线性中文型微分方程的振动准则

考虑时间轴上非线性中立型微分方程(x(t)-p(t)x(t-σ))Δ=f(t,x(t),x(t-τ(t)))的振动性,获得了该方程所有解振动的充要条件.     

高阶非线性中立型方程的振动定理

研究了一类具有连续分布滞量的高阶非线性中立型方程{a(t)[x(t)+m∑i=1ci(t)x(iτ(t))](n-1)}′+b∫af(t,,ξx(g(t,ξ)))dσ(ξ)=0的振动性,利用R iccati变换并运用分析方法和技巧,得到了该类方程新的振动准则,所得结论推广和改进了已知文献的部分结果.     

高阶非线性中立型方程的振动定理

研究了一类具连续分布滞量的高阶非线性中立型方程{a(t)[x(t) m∑i=1 ci(t)x(τi(t))](n-1)}' ∫baq(t,ξ)f(x(g(t,ξ)))dσ(ξ)=0的振动性,利用一般的Riccati变换和完全平方技术,通过引进参数函数H(t,s),并在减弱H(t,s)的条件下,获得了方程更一般性的振动准则,所得结论改进并推广了已知文献中的部分结果.     

一类非线性中立型时滞差分方程的振动性

研究了一类非线性中立型时滞差分方程Δ(x(n)-p(n)g(x(n-τ)))-q(n)h(x(n-δ))=0解的振动性.其中:p(n),q(n)是实数序列,g,h∈c(R,R),τ>0,δ≥0.通过建立与某个线性中立型差分方程的联系导出了一个较简单的振动准则.     

一类线性偏微分方程的相似解

研究方程((e)u)/((e)t)=xpΔu, (x,t)∈R2×(0, ∞)的具有形式u(x,t)=(t 1)λw(ξ)的相似解的存在惟一性及渐近性质,这里0≤p<2,λ∈R,ξ=(xβ)/((t 1)α),α>0,β=α(2-p).     

具正负系数的二阶中立型微分方程的振动性

研究了下列具有正负系数和多个变时滞的二阶非线性中立型微分方程{A(t)[x(t)+P(t)x(τ(t))]′}′+∑mi=1[Qi(t)fi(x(σi(t)))-∑kj=1Rij(t)gij(x(δij(t)))]=0,t≥t0的振动性.通过引入参数函数与Riccati变换,获得了该方程振动性的一些判别准则.这些结果改进并推广了已有文献中的相关结果.     

一类二阶非线性中立型时标动态方程的振动性

主要利用时标理论的知识及广义Riccati技巧,(给出了二阶非线性中立型时标动态方程r(t)((y(t)+p(t)y("(t)))Δ)γ)Δ+f(t,y(δ(t)))=0,当γ为不可约正奇数的商时的新振动准则.     

时间模上一类二阶非线性中立型泛函动态方程的振荡性

为了进一步发展和完善时间模上动态方程的振荡理论,研究了时间模上一类二阶非线性中立型变时滞的动态方程[a(t)|y~Δ(t)|~(α-1)y~Δ(t)]~Δ+q(t)|x(δ(t))|~(β-1)x(δ(t))=0的振荡性(这里y(t)=x(t)+p(t)x(τ(t));α0,β0为实常数),得到该方程振荡的一些新准则,推广并改进了一些已有的结果.     

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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