高阶非线性中立型微分方程的周期解

利用重合度理论,研究高阶非线性中立型泛函微分方程[x(t)+cx(t-τ)](n)+f(x(t))x’(t)+g(x(t-σ))=p(t)的周期解的存在性,给出了该方程存在周期解的充分性定理,推广了已有的结果.     

一类二阶非线性中立型泛函微分方程周期解

利用重合度理论,研究了一类二阶非线性中立型泛函微分方程[x(t)+cx(t-τ)]"+f(t,x(t),x'(t))+g(t,x(t-γ(t)))=p(t)的周期解的存在性,得到了周期解存在的充分条件.     

二阶中立型微分方程的周期解

应用Krasnoselskii不动点理论,研究了一类二阶中立型微分方程[x(t)+Σni=1cix(t-τi)]″=a(t)x(t)-f(t,x(t-σ(t)))周期解的存在性。     

一类二阶中立型Rayleigh方程周期解的存在性

利用Mawhin重合度拓展定理,研究了一类二阶中立型Rayleigh方程[x(t)+ni=1"cix(t-τi)]'=f(x'(t))+g(x(t-γ(t))+p(t)周期解的存在性,给出了该方程存在周期解的充分性定理。     

一类高阶Rayleigh型方程周期解的存在性

本文利用重合度理论研究一类高阶Rayleigh型方程x(n)(t)+f(x’(t))+g(x(t-τ(t)))=p(t)周期解的存在性,获得了其2π-周期解存在性的若干结论。     

具有变系数的高阶中立型微分方程正解的存在性

利用Banach压缩映象原理给出了具有变系数p(t)的2n+1阶中立型微分方程 [x(t)-p(t)x(t-τ)](2n+1)+f(t,x(t-τ1(t)),…,x(t-τm(t)))=0正解存在的几个充分条件.     

一类二阶多时滞泛函微分方程多个周期解的存在性

利用重合度理论获得了二阶多时滞泛函微分方程xw(t)+f(t,x(t-τ1(t),x(t-τ2(t)))(x'(t))n+f(x(t))·x'(t)+a(t)x2(t-τ3(t))+b(t)x(t-τ3(t))=p(t)(n≥2)多个周期解的存在性,得到了这类方程至少存在2个周期解的结论.     

一类时滞Liénard型方程的周期解

采用更精确的先验估计,利用Mawhin的延拓定理,研究具有周期扰动的n维时滞Li啨nard型方程¨x(t)+ddtgradF(x)+gradG(x(t-τ))=p(t),获得此方程至少存在一个2π周期解的充分条件.     

一类二阶中立型泛函微分方程周期解的存在性

利用重合度理论,研究一类二阶中立型泛函微分方程(x(t)-cx(t-σ))″ g(t,x(t-τ(t)))=p(t)的周期解的存在性,得到了周期解存在的新的结果.     

一类三阶时滞Duffing型方程周期解的存在唯一性

利用重合度理论,研究一类三阶时滞Duffing泛函微分方程x(t)+∑2i=1[aix(i)(t)+bix(i)(t-τi)]+cx(t)+g1(t,x(t))+g2(t,x(t-τ(t)))=e(t)的T-周期解问题,获得了该方程T-周期解存在性和唯一性的若干新结果.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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