时滞细胞神经网络模型的全局吸引性和全局指数稳定性

借助于Liapunov第二方法 ,对具有时滞的细胞神经网络系统x′i(t) =-Cixi(t) ∑nj=1aijfj(xj(t) ) ∑nj=1bijfj(xj(t-τj) ) Ii,　i=1,2 ,… ,n ,在非线性神经元激励函数满足Lipschitz连续的条件下 ,研究了这类模型全局吸引和平衡点全局指数稳定的问题 ,获得了易于验证的充分条件     

含时滞的Hopfield网络模型的全局指数稳定性

本文研究了具有变时滞的细胞神经网络系统·xi(t)=-cixi(t) n∑j=1αijfj(xj(t)) n∑j=1bijfj(xj(t-τj)) Ii,i=1,2,…,n.在非线性神经激励函数是Lipschitz条件下,通过引入Lyapunov函数,用不等式等方法,得到了该系统的平衡点是全局指数稳定的条件.     

变连接权时滞细胞神经网络的概周期解

利用不动点理论和微分不等式分析等方法，研究了具有变连接权的时滞细胞神经网络dxi（t）/dt=-cixi（t）＋∑j=1^nαij（t）fi（xi（t））＋∑j=1^nbij（t）fj（xj（t-τ（t）））＋li（t）的概周期解的存在性和全局吸引性，推广和改进了相关文献的结果，扩大了神经网络的设计范围．     

二阶线性非自治时滞微分方程的稳定性

研究了非自治时滞微分方程x′i(t) ∑2j= 1aij(t)xj(hij(t))= 0,t≥0,i= 1,2平衡点(x1,x2)T = (0,0)T 的稳定性,应用Liapunov 泛函方法得到该系统稳定性的条件.这些检验方程对于进一步研究数值方法中的稳定性提供了理论基础.     

一类具变滞的微分方程的稳定性

本文利用Lyapunov泛函及不等式,研究了一类变时滞线性中立型泛函微分方程[x（t）-m∑i=1aix（t-τi）]＇=bx（t）＋n∑j=1＋cjx（t-δj（t））的稳定性,并得到其零解渐进稳定性的充分条件．     

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．     

时滞细胞神经网络模型的渐近性态分析

对具有时滞的神经网络模型xi(t)=-Cixi(t) ∑j=1^n aijfj(xj(t)) ∑j=1^n bijfj(xj(t-τj)) Ii,i=1,2,…,n,在非线性神经元激励函数满足Lipachitz连续的条件下通过构造适当的泛函，研究了这类模型的渐近性态，获得了这类模型全局吸引和平衡点的全局指数稳定易于验证的充分条件．     

具有多偏差变元二阶中立型方程周期解问题

利用重合度理论,讨论了含有变时滞的一类二阶中立型泛函微分方程：d^2/dt^2[x（t）-kx（t-τ（t））]＋∑i=0^m αi（t）f（x（t））,x（t-μi（t）））＋∑i=0^m βi（t）g（x（t-γi（t）））=p（t）周期解存在性问题,得到了周期解存在的充分条件．     

具有离散时滞的非自治扩散的N种群竞争模型

1模型与概念文献[1]给出了如下具有时滞的Lotka-Voltrra竞争模型x(t)=x(t)(r1-ax(t-τ)-by(t))y(t)=y(t)(r2-cx(t)-dy(t))本文将上述模型推广到非自治的N种群竞争扩散模型进行讨论.考虑如下形式的模型x·i(t)=xi(t)(ri(t)-aii(t)xi(t-τ)-∑nj=1,j≠iaij(t)xj(t))x·n(t)=xn(t)     

一类P—Laplace方程解的有界性研究

研究二阶微分方程（Фp（x^1））^1＋x^2n＋1＋∑^2nj=0x^jpj（t）=0,n≥1,x∈（-∞,∞）解的有界性。     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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