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。     

具有脉冲的时滞方程x′（t）=r（t）1—ex（t—x）／1λe^x（t—τ）的解的渐近分析

考虑具有脉冲的时滞方程x′(t) =r(t) 1-ex(t-τ)1+λex(t-τ) ,t≥t0 ,t≠tk,k=1,2 ,… ,x(t+ k) -x(tk) =bkx(tk) ,k =1,2 ,… ,( )其中τ >0 ,λ>0 ,r(t)∈C([t0 ,+∞ ) ,R+ ) ,bk>- 1且 {tk}满足t0 相似文献   

一类具有脉冲的时滞微分方程的全局吸引性

考虑具有脉冲的时滞微分方程:N′(t)=r(t)N(t)1-N(t-τ)1-λN(t-τ),　t≥0,t≠tk,k∈N,lnN(t+k)-lnN(tk)=bklnN(tk),　k∈N,( )其中,τ>0,λ∈(0,1),r∈C([0,+∞),R+),bk>-1,且{tk}满足0相似文献   

一类二阶非线性脉冲常微分方程振动的充分条件

用黎卡堤变换研究如下二阶非线性脉冲微分方程{x(tk^ )=x(tk),r(tk)x′(tk^4)=r(tk)x′(tk^-)-gk(x(tk)),k=1,2,3…,^(r(t)x′(t))′ f(t,x)=0,t≠tk,得到了两个判断方程振动的充分条件．     

无穷区间上二阶脉冲积微分方程的解

利用锥理论和单调迭代技巧，得到了Banach空间中无穷区间上二阶脉冲积微分方程初值问题{x″=f(t,x,x′,Tx),t≥0,t≠tk,；△x|t=tk=Ik(x∈（tk））,；△x′|t=tk=Ik(x′（tk）），；x(0)=x0,x′(x)x0^n的解存在的充分条件。     

二阶脉冲微分方程的解的渐近性态

研究得到二阶脉冲微分方程{p(t)x'(t)' a(t)x(t)=0,t≥t0,t≠tk,k＝1,2,… x(tk^ )=gk(x(tk)),x'(tk^ )=hk(x'(tk)),k=1,2…的解有界或趋于零的充分条件。     

具连续变量线性脉冲时滞差分方程的振动性

研究具连续变量的脉冲时滞差分方程{y(t)-y(t-τ） m∑j=1pj(t)y(t-σj）=0,t≠tk,y(tk^ )-y(tk)=bky(tk),k=1,2,…得到了方程所有解振动的若干充分性条件。}     

具连续变量的脉冲多时滞差分方程的振动性

研究了如下具有连续变量的脉冲时滞差分方程x(t)-x(t-τ)+∑i=1 m pi(t)x(t-σi)=0,t≥0, t≠tk x(t+k)-x(tk)=bkx(tk),k=1,2,…通过构造辅助函数,得到了方程解振动的两个充分条件,推广和改进了已有文献中的某些结果.     

一类具脉冲时滞微分方程解的渐近性

本文考虑脉冲时滞微分方程{x＇（t）＋a（t）x（t）＋f（t,x（t-τ））=0,1≥0,t≠tk, x（t＇k）-x（tk）=bkx（tk）,k∈N,获得了方程每一解x（t）满足limt→∞x（t）=0的充分条件．     

具有脉冲的积分微分系统解的稳定性

主要利用分段连续的李雅普诺夫函数来给出脉冲积分微分系统{dx/dt=Ax(t) ∫0^1C（t,s)x(s)ds,t≠tk Δx=Ik（x），t=tk，k=1，2，…零解稳定性的充要条件。     

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.     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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