一类具有非线性传染率的SIS传染病接种模型的研究

研究了一类具有非线性传染率的SIS传染病接种模型的全局稳定的动力学行为,找到了疾病存在与否的阈值——基本再生数R_0。当R_0≤1时,疾病消逝;当R_01时,疾病流行。同时,利用Lyapunov-LaSalle不变集原理,证明了无病平衡点和地方病平衡点的全局渐近稳定性。     

具有饱和发生率与混合控制策略的SEIQR模型的全局动力学（英文）

建立了一个具有饱和接触率和混合控制策略的SEIQR传染病模型,从理论和数值模拟方面分析了模型的稳定性.首先,得到了疾病灭绝与否的阈值——基本再生数R_0;其次,当R_01时,利用LaSalle不变集原理证明了无病平衡点是全局渐近稳定的,疾病最终消亡.当R_01时,根据Routh-Hurwitz判据定理证明了地方病平衡点局部渐近稳定;然后,当R_01时,运用周期轨道稳定性理论和第二加性复合矩阵证明了地方病平衡点全局渐近稳定,疾病持续存在;最后,利用计算机仿真,进一步证实理论分析的正确性.     

一类具有常数输入率的结核病模型稳定性分析

研究了一类具有接种仓室和潜伏仓室的结核病模型,得到了结核病灭绝与否的阈值——基本再生数R0,并运用Liapunov函数,中心流行理论、La Salle不变集原理证明了当R0≤1时,此模型存在唯一的无病平衡点E0,且无病平衡点全局渐近稳定;当R01且无限接近于1时,地方病平衡点E*局部渐近稳定;当R01时,地方病平衡点E*全局渐近稳定.且用数值模拟进一步证明了无病平衡点和地方病平衡点稳定性.     

潜伏类和移出类具有传染性的SEIR模型的渐近性分析

研究了一类潜伏类和移出类均具有传染力的SEIR传染病模型,得到了疾病流行与否的阈值:基本再生数R_0.运用Liapunov函数方法,证明了当R_01时,无病平衡点E_0全局渐近稳定,疾病最终消失;利用Hurwitz判据定理,证明了当R_01时,E_0不稳定,地方病平衡点E*局部渐近稳定;当因病死亡率和剔除率为零时,地方病平衡点E*全局渐近稳定,疾病持续存在.最后,进行了计算机数值模拟来进一步验证理论结果的正确性.     

一类具有接种和治疗的传染病模型动力学分析

假设被接种者获得的免疫会逐渐丧失,建立了一类具有接种和治疗的传染病模型,并对模型的稳定性进行了分析.通过构造Lyapunov函数以及利用判据和Lasalle不变原理,研究了模型的无病平衡点和地方病平衡点的稳定性,并找出影响传染病是否流行的阈值R_0.结论表明模型始终存在一个无病平衡点,且它在R_01时全局渐近稳定;R_01时还存在一个地方病平衡点,且它是全局渐近稳定的.     

具有饱和接触率与混合控制策略的SIQR模型的动力学分析

考虑接种、隔离和剔除混合控制策略,建立了一个具有饱和接触率的SIQR传染病模型,从理论分析和数值模拟方面研究了该模型的全局稳定性.首先,通过计算得到了疾病灭绝与否的阈值—基本再生数R₀和平衡点存在的条件;其次,当R₀<1时,利用Liapunov函数证明了无病平衡点P₀是全局渐近稳定的;然后,当R₀>1时,运用Dulac函数证明了地方病平衡点P^*是全局渐近稳定的;最后,利用计算机仿真,进一步证实理论分析的正确性.     

一类带有隔离的百日咳SIQR2 R1 S传染病模型

考虑带有隔离且具有非线性发生率的百日咳传染病模型,确定了疾病是否流行的阈值,利用Lyapunov函数、La Salle不变集原理和Routh-Hurwitz判据对模型进行分析,当R0≤1时,百日咳传染病模型的无病平衡点全局渐近稳定;当R_0 1时,无病平衡点不稳定,且模型还存在唯一的地方病平衡点,进一步讨论了在特殊情况下地方病平衡点的局部稳定性和一般情况下Hopf分支产生的条件.     

一类流行性出血热模型的全局稳定性

建立和分析了一类流行性出血热传播模型,定义了模型的基本再生数R_0,并利用Routh-Hurwitz判据、Lyapunov函数、LaSalle不变集原理和合作系统理论,讨论了模型平衡点的局部和全局渐近稳定性.结果表明:当R_01时,模型仅存在唯一的无病平衡点,且无病平衡点是全局渐近稳定的;当R_01时,无病平衡点不稳定,模型还存在地方病平衡点,且地方病平衡点全局渐近稳定.     

一类离散型结核病模型的全局稳定性

本文研究了一类离散型结核病模型.利用求再生矩阵谱半径的方法,计算得到模型的基本再生数R_0.运用差分方程相关理论,证明了模型解的正性和有界性.通过构造适当的Lyapunov函数,证明了R_0=1是决定疾病消失或者持续的阈值.当基本再生数R_01时,无病平衡点是全局渐近稳定的;当基本再生数R_01时,地方病平衡点是全局渐近稳定的.     

一类具有垂直传染的非线性发生率的SIS传染病模型的稳定性分析

讨论了一类具有垂直传染的非线性发生率的SIS传染病模型,得到了阈值R_0。并讨论了当R_0≤1时,无病平衡点是全局渐近稳定的,而当R_01时,地方病平衡点是全局渐近稳定的。     

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     

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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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has