一类具有传染病捕食与被捕食模型的稳定性

考虑了带有时滞和比率依赖且在捕食者中有传染病的捕食与被捕食模型,通过分析模型在灭绝平衡点,无病平衡点,共存平衡点相应的特征方程,利用微分方程理论,讨论了模型在平衡点的局部稳定性,并用数值模拟验证结果.     

一类捕食者有病的捕食-被捕食的SIS模型

建立了一类捕食者有病的捕食-被捕食的SIS模型,并讨论了系统平衡点的稳定性,得到了无病平衡点和地方病平衡点稳定的条件.     

一类具有收获率的捕食-被捕食模型的渐近性

讨论了一类具有收获率的捕食-被捕食模型.利用代数方程得到了该模型存在平衡点的充分条件,应用Hurwitz判别法则及特征方程给出了该模型的平衡点局部渐近稳定的充分条件.最后通过实例说明所得结论的可实现性.     

一类具有Beddington-DeAngelis功能反应函数的捕食被捕食模型Hopf分岔分析

建立了一类具有Beddington-DeAngelis功能反应函数的捕食-被捕食模型,分析了其平衡点的稳定性,得到其平衡点稳定的条件.选择时滞t作为分岔参数,得到了其发生Hopf分岔的临界值,并通过数值模拟验证了理论分析的正确性.     

带有多时滞疾病的捕食被捕食系统的稳定性

建立并分析了一个具有多时滞的疾病在食饵和捕食者中都染病的捕食被捕食模型.首先得到了边界平衡点及正平衡点存在的条件,然后利用特征根法得到含有多时滞的非线性特征方程,通过讨论得到平衡点局部渐近稳定的充分条件,研究了各平衡点是否可以出现Hopf分支现象.数值模拟也验证了理论分析.     

害鼠治理中一类在食饵中具有不育控制的捕食与被捕食模型

研究了一类食饵中具有不育控制的捕食与被捕食模型,讨论了模型解的有界性及零平衡点和正平衡点的局部稳定性,通过构造适当的Lyapunov函数并运用La Salle’s不变原理,证明了正平衡点的全局稳定性.     

具有多时滞影响的阶段结构捕食-被捕食模型研究

研究一个捕食者与被捕食者均有时滞影响的且捕食者只捕食幼年食饵的捕食-被捕食模型,通过构造适当的Lyapunov泛函,讨论了该模型的正平衡点与非负边界平衡点的渐进稳定性,从而得到了该生态模型的永久持续生存与灭绝的充分性条件。     

一类具有功能性反应的捕食离散模型的稳定性

给出了一类具有功能性反应的捕食被捕食离散模型正平衡点的存在条件,利用代数中特征值判别法得到正平衡点局部稳定的充分条件,通过构造适当的L iapunov函数,讨论了正平衡点的全局稳定性.     

具有收获率的Kolmogorov捕食-被捕食模型

研究了具有收获率的Kolmogorov捕食-被捕食模型,讨论了该模型正平衡点的性态,验证了解的有界性,得到了模型惟一正平衡点是全局渐近稳定的.     

带有时滞的捕食与被捕食系统的稳定性和分支

研究了一类带有时滞的捕食与被捕食系统.利用特征方程分析了系统平衡点的稳定性,得到了平衡点局部稳定的充分条件.通过选择适当的参数,当时滞取得一些数值时,系统将会产生Hopf分支.     

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