一类时滞脉冲微分方程概周期解的存在性

利用普通型二分性和不动点原理,研究了时滞脉冲微分方程x′=A(t)x+f(t,x(t-τ)),t≠t k△x(t)=B kx(t)+I k(x(t)),t=t k,k∈Z的概周期解,得到了系统存在概周期解的一组充分条件.     

一类具有逐段常变量微分方程的渐近概周期解

通过构造差分方程的渐近概周期序列解,讨论了具有逐段常变量的微分方程x（t）=ax（t）＋bx（[t]）＋F（t,x）的渐近概周期解的存在性．     

一类中立型积分微分方程概周期解的存在性和唯一性

考虑具连续时滞和离散时滞的中立型积分微分方程d/dt[x（t）＋^q∑j=1 ej（t）x（t-δj（t））]=A（t）x（t）＋^t∫-∞C（t,s）x（s）ds＋^p∑i=1gi（t,x（t-τi（t）））＋b（t）概周期解的存在性和唯一性问题．利用线性系统指数型二分性理论和压缩映射原理,获得了保证中立型系统概周期解存在性和唯一性的一组充分条件,推广了相关文献的主要结果．     

中立型Voherra积分微分方程概周期解的存在唯一性

研究了中立型Volterra积分微分方程x’（t）=A（t）z（t）＋∫-∞^t C（t,s）g（s,x（s））ds＋∫-∞^t B（t,s）x’（s）ds＋f（t,x（t））的概周期解的存在性及唯一性问题．利用不动点方法,得到了一些关于该方程的概周期解的存在性及唯一性的新结果．     

二阶中立型含逐段常变量微分方程的概周期解

讨论二阶中立型含逐段常变量泛函微分方程d²/dt ² ( x ( t)+0- p(s) x ( t+s)ds) =qx( 2[（t+1）/2] ) + g( t, x ( t),x[t] ) 的概周期解问题. 利用不动点方法及对差分方程构造概周期解, 获得了概周期解存在的充分条件.     

高维非自治系统概周期解的存在性和指数型渐进稳定

考虑高维非自治系统.x=A(t,x)x+g(t,x)的概周期解的存在性和稳定性,通过引进实对称有界正定矩阵,利用指数型二分性和稳定性有关理论得到了上述系统在一定的条件下存在着唯一指数型渐进稳定的概周期解,得到了新结果.     

一类二阶迭代微分方程的周期解

研究一类二阶迭代泛函微分方程x（t）＋g（x（x（t）））=f（t,x（t）,x（t））的周期解的存在性,通过使用不等式技巧,获得了该系统周期解的界的更精确的先验估计,从而利用重合度理论建立了在同类条件下这类系统周期解存在的最优存在性判据,改进了相应文献中的结论．     

二阶混合型脉冲积微分方程初值问题

利用上下解方法和单调迭代技术研究定义在无界域上的脉冲积微分方程的初值问题｛x″=f(t,x,Tx,Sx),t≠tκ,(κ=1,2…），t∈J，△x|t=tκ=Iκ（x(tκ）），（κ=1,2,…），△x′|t=tκ=～↑Iκ（x′（tκ）），（κ=1,2,…），x(α）=x0,x′（α）=x0^*,建立了该问题的解的存在性定理。     

一类具偏差变元的p-Laplacian泛函中立型微分方程周期解的存在性

运用迭舍度理论和分析的技巧,研究一类具偏差变元形如（φp（x（t）-cx（t-σ）＂）＂＋g（t,x（t-τ（t）））=p（t）的中立型p-Laplacian微分方程,并得到了其周期解存在的充分条件．     

含n个滞量的微分差分方程周期解的存在性

通过构造多元函数,定性分析一个耦合自治常微分方程组周期解的存在性,研究含多个滞量的微分差分方程x′（t）=F（x（t）,x（t-τ1）,x（t-τ2）,...,x（t-τn））和x′（t）=F（x（t）,x（t-τ）,x（t-2τ）,…,x（t-nτ））周期解的存在性问题,获得系统存在非平凡振动周期解的一组充分条件,推广和改进了文献[3～5]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.     

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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