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.     

变时滞细胞神经网络模型的全局指数稳定性

研究了具有变时滞的细胞神经网络系统nx.i（t）=-cixi（t）＋∑nj=1aijfj（xj（t））＋∑nj=1bijfj（xj（t-τj（t）））＋Ii,i=1,2,…,n.在非线性神经激励函数满足Lipschitz条件下,借助于推广的Halanay时滞微分不等式等方法,得到了该系统的平衡点是全局指数稳定的条件.     

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     

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．     

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.     

Hopfield型时滞神经网络模型的K-稳定性

研究具有时滞的Hopfield型神经网络模型｛Cidui(t)/dt=-ui(t)/Ri n↑∑↑j=1～↑Tijfi(uj(t-τ）） Ii，ui（s）=ψi(s),s∈[-τ，0],i=1,2,…，n平衡点的K－全局渐近稳定性与K－全局指数稳定性，通过使用不等式分析技巧和微分方程性质，得到了这类模型K－稳定性的易于验证的时滞相关充分条件，并举例验证其有效性。     

多时滞一阶非线性微分方程组的振动性及其应用

讨论多时滞一阶非线性微分方程组dxi(t)/dt mΣj=1aij(t)fij(xj(t-τj(t)))=0,i=1,2,…,m. 的所有解振动的充分条件.同时我们也得到了多时滞LOGISTIC方程组dNi(t)/dt=Ni(t)[ai-mΣj=1bijNj(t-τj)],i=1,2,…,m.的所有正解关于它的平衡点振动的充分条件.     

一类复杂动力学网络的滑模控制混沌同步

滑模控制作为一种重要的鲁棒控制策略,得到广泛的应用,运用滑模控制实现多个具有相互关联的混沌系统的同步问题还鲜有报道。本文利用滑模控制方法研究了一类复杂动力学网络的同步控制问题,该系统的驱动系统为i=Cxi+1+f(xi+1),n=g(x1,x2,…,xn),而响应系统为j i=Cxj i+1+f(xj i+1),j n=g(xj1,xj2,…,xj n)+ξj+uj,结果表明选取适当的滑模面和控制律,该混沌系统是同步的。文章基于Lyapunov稳定性理论,设计了网络滑模面以及控制输入,如果选取适当的可调参数,可得到V·<0,从而在滑模控制方法下多个混沌系统构成的复杂动力学网络是混沌同步的,仿真算例说明了该方法的有效性。     

线性模型下分布函数的估计

利用辅助信息,针对线性模型yi=βxi xi^yεi,εi i.i.d,Fεi=0,给出了总体分布函数的估计量：F（t)=1/N[∑j∈iΔ(t-yi) ∑j∈,1/n∑j∈Δ（t-β^*xi-xi^yuj)],uj=(yj-β^*xj)/xjy^*,j∈s,改进了Chambers-Dunstan的结果。     

广义时延神经网络的渐近稳定性

讨论如下带有时延的广义神经网络模型(dxi)/(dt)=Gi(xi)[bi(xi)-∑nj=1cijdj(xj(t-τj))], i=1,2,...,n,其中,τj＞0为第j个神经元的时延,cij表示第j个神经元在t-τj时刻的输出对第i个神经元的影响强度,t∈I=[t0,∞),x∈Rn.利用Lyapunov函数及推广的Halanay微分不等式,研究了该模型的渐近稳定性,给出了系统指数稳定的几个充分条件及相应的Lyapunov指数.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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