时滞随机系统的时滞相关稳定性

将自由权矩阵思想推广到一类时滞随机系统中,研究了其时滞相关稳定性问题.通过构造新的Lyapunov函数,引入适当的自由权矩阵,推导出系统渐近稳定的时滞相关的充分条件.所得结果完全基于线性矩阵不等式的形式给出,不需要对原系统模型进行变换.数值算例说明了方法的可行性.     

区间时变时滞广义系统的稳定性分析

研究了区间时变时滞广义系统的稳定性问题.通过构造新的Lyapunov泛函,使用时滞分割和自由权矩阵方法,以严格线性矩阵不等式形式给出了使得系统正则、无脉冲且稳定的时滞相关型稳定性新判据.数值实例表明了结果的有效性和较小保守性.     

一类不确定时滞大系统的分散鲁棒镇定

主要研究了一类控制输入时滞和关联时滞均为时变时滞的不确定时滞大系统的分散鲁棒镇定问题.基于不确定项的表达形式,分别利用Riccati矩阵不等式方法和线性矩阵不等式方法,给出了其可分散状态反馈镇定的充分条件,最后通过一组数值算例证明了这种方法的有效性.     

多时滞中立型系统时滞相关稳定性分析

讨论多时滞中立型系统的时滞相关稳定性.首先考虑了二维时滞中立型系统时滞相关稳定条件.通过引入自由权矩阵,描述了Leibniz-Newtow公式中各项间的关系.以线性矩阵不等式的形式给出了时滞相关稳定条件.数值例子说明所得结论比已有结果具有较小的保守性.最后将这一标准推广到多时滞中立型系统.     

具有时变时滞大系统的新的稳定性条件

应用矩阵的相似变换原理和矩阵指数特性,通过估计微分方程的解,导出了一类具有时变时滞的大系统的时滞无关稳定性条件.其结论仅需时滞具有正数界,克服了已有文献结论中的对时滞的苛刻的约束条件,并给出了一个数值实例,实例仿真结果表明,所得结果优于现有文献的结果.参10.     

状态滞后区间系统的鲁棒H∞控制

研究了系统矩阵、时滞矩阵和输入矩阵均含有不确定性的状态滞后区间矩阵系统的H∞鲁棒控制问题.利用区间矩阵定义的等价形式使其结构化,运用矩阵不等式给出了时滞区间控制系统H∞鲁棒镇定的充分条件,并根据所给充分条件解一个代数R iccati方程,从而得到H∞鲁棒镇定控制律.     

一类不确定时滞系统的稳定性条件

在系统不确定矩阵的范数有一定限制的情况下,利用比较定理及矩阵范数与测度的有关性质,给出了一般不确定时滞系统及对称组合不确定时滞系统的稳定性条件.在对称组合系统的情形下,还给出了时滞相关型的稳定条件.     

常时滞细胞神经网络稳定性分析

该文研究了一类常时滞细胞神经网络的稳定性.构造Lyapunov-Krasovskii函数和线性矩阵不等式(LMI)对此类问题进行了探讨,并得出稳定性判据.所得判据提供了一些参数来适当地弥补了反馈矩阵与时滞反馈矩阵之间的平衡关系.而且所得的判据与时滞无关,推广了以前文献中出现的结果且具有更少的限制.数值仿真说明了该文所介绍的方法的有效性.     

一类含离散与分布时滞的奇异系统的鲁棒稳定性

讨论了一类含离散与分布时滞的不确定奇异系统的时滞相关鲁棒稳定性.基于Lyapunov稳定性理论, 利用线性矩阵不等式处理方法, 通过在Lyapunov-Krasovskii泛函的导数中适当地引入一些自由矩阵, 获得了系统时滞相关鲁棒稳定充分条件.数值例子表明所得结果是有效的.     

一种改进的动态矩阵控制算法

提出一种动态矩阵控制算法的改进算法,并用该算法对具有大时滞的系统进行研究.通过仿真试验与常规动态矩阵算法控制进行了比较,结果表明改进的动态矩阵控制算法在大时滞系统控制中具有较好的控制效果.     

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     

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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