具连续变量的二阶时滞差分方程的振动性

研究一类具有连续变量的二阶时滞差分方程△2τx(t)=p(t)x(t-σ)t≥t0＞0和△2τx(t)=m∑i=1Pi(t)x(t-σi),t≥t0＞0的解的振动性,给出了其有界解振动的几个充分条件.     

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.     

具有多变时滞中立型微分方程的振动性

讨论具有多变时滞的中立型微分方程[x(t)-r(t)x(t-τ)]’+p(t)x(t-σ1)-q0(t)x(t-σ2)+Σmi=1qi(t)x(t-γi(t))=0,得到方程所有解振动的一个充分条件.     

二阶线性中立型时滞微分方程非振动解的存在性

研究具正负系数的二阶线性中立型时滞微分方程d2dt2 [x(t) p(t) x(t-τ) ] Q1 (t) x(t-σ1 ) - Q2 (t) x(t-σ2 ) =0 ,得到了该方程存在非振动解的充分性条件     

具振动系数的中立型时滞微分方程解的渐近性

考虑具有振动系数的中立型时滞微分方程[x(t) p(t)x(t-τ(t))] Q(t)x(t-σ）＝0，t大 于等于0，其中p,Q属于C（[0,∞),R),τ属于（0，∞），σ属于[0,∞）Q（t)最终不恒为零。记Q＋（t)=max(0,Q(t)},Q-(t)＝－min{0,Q(t)}.获得了该方程的每一个解或者振动或者趋于零的一个新的充分条件。     

具有连续变量的中立型差分方程的振动准则

研究了一类具有连续变量的中立型差分方程△τ(x(t)-px(t-τ)) q(t)mⅡi=1|x(t-σi)|αisgnx(t-σi)=0的振动性,建立了该方程振动的几个充分条件.     

一类一阶中立型时滞微分方程解的振动性

考虑一阶中立型时滞微分方程d/dt[x(t) p(t)x(t-τ)] f(t,x(t-σ))=0,其中p∈C([t0,∞),R),q∈C([t0,∞),R ),τ,σ∈R ,f(t,x)是定义在[t0, ∞)×R上的连续函数,讨论了上述方程的解的振动性,得出了该方程的一切解振动的充分条件。     

二阶连续变量线性脉冲时滞差分方程的振动性

研究了具有连续变量的脉冲时滞差分方程 {△τ^2x(t) ∑^i=1^npi(t)x(t-σi)=0,t≠tk,x(tk^ )-x(tk)=bkx(tk),t=tk,的振动性，其中σ＞0；τ＞0，pi∈（R^ ，R^ ),(i=1,2,…,n)，得到了该方程所有解振动的两个充分条件。     

一阶非线性中立型微分方程振动的充分必要条件

本文考虑非线性中立型微分方程d/dt[x(t)-P(t)x(ι-τ)] Q(t),multiply from i=1 to (?)[x(t-σ_1)]~αsignx(t-σ_1)=0当P(t)=1时,我们获得了如上方程一切有界解振动的充分必要条件,而不要求公设integral from n=(?) to ∞(Q(s)ds=∞)     

一类脉冲时滞双曲型方程解的振动性

利用Robin特征值方法，对如下的脉冲时滞方程{uu(x，t)=a(t)△u(x，t) b(t)△u(x，t-δ)，-h(x，t)u(x，t-σ)-q(x，t)f[u(x，t-ρ)]，t≠tk，u(x，tk^ -u(x，tk^ )=cku(x，tk)，k=1，2，3，…，ut(x，tk^ )-ut(x，tk^ )=ckut(x，tk)，k=1，2，3…的振动性进行了讨论，并得到了方程振动的充分条件。     

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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