一类商环的结构

通过构造同构映射，讨论了商环Ｉ「ｘ」／（ｎ＋ｘ＾２）及Ｉｘ／（ａｘ＾２＋ｂｘ＋ｃ）的结构及主要性质，从而推广了文「１」的主要结论。     

方程x＋f（x）x＋g（x）=0零解的全局渐近稳定性

本文讨论了Ｌｉｅｎａｒｄ方程ｘ＋ｆ（ｘ）ｘ＋ｇ（ｘ）＝０的零解的全局渐近稳定性，所得结果包含了文「１－４」的主要结果。     

Lurie型鲁棒控制系统的绝对稳定性

在实数Ｒ上一切闭区间组成的集合和区间矩阵的集中中引进了代数运算，讨论了Ｌｕｒｉｅ型直接鲁棒控制系统ｘ＝Ｇ「Ｂ，Ｃ」ｘ＋Ｇ「Ｒ，Ｓ」ｆ（σ）；σ＝ｃ＾Ｔｘ，ｆ（．）∈Ｋ「０，∞」和间接鲁棒控制系统ｘ＝Ｇ「Ｂ，Ｃ」ｘ＋Ｇ「Ｒ，Ｓ」ｆ（σ）；σ＝ｃ＾Ｔｘ－．ｆ（．）∈Ｋ「０，∞」display structure     

包围个奇点的广义Lienard系统极限环的个数

研究广义Ｌｉｅｎａｒｄ系统ｘ＋（ｆ（ｘ）＋ｋ（ｘ）ｘ）ｘ＋ｇ（ｘ）＝０,获得了包围多个奇点的极限环唯一性和唯二性三个充分条件,推广和改进了文「１」的主要结果。     

具有分段常自变元的时滞微分方程解的振动性

考虑方程（ａ）（ｘ（ｔ）－ｃｘ（ｔ－２「ｔ＋１）／２」））’＋ｐ（ｔ）ｘ（ｔ）－２「（ｔ＋１）／２」）＋ｑ（ｔ）ｘ（２「（ｔ＋１）／２」＝０解的振动性和方程（ｂ）（ｘ（ｔ）－ｃｘ（ｔ－τ））’＝ａ（ｔ）ｘ（ｔ）＋ｂ（ｔ）ｘ「ｔ－ｋ」）解的非振动性,得到方程（ａ）的解振动的充分条件和方程（ｂ）的解非振动的充分条件。     

捕食者种群具有常投放率的Ⅱ类功能性反应模型的定性分析

文「１」讨论了捕食者种群具有常收获率的Ⅱ类功能性反应模型，证明了此系统存在正平衡点时，在第一象限必全局不稳定，如果将常收获率改为常投放率，这时的数学模型变成｛ｘ＝ｘ（ａ－βｙ／１＋ωｘ） ｙ＝ｙ（－ｂ＋γｘ／１＋ωｘ）＋Ｋ。系统①中所有系数均任意正常数。     

多项式的特征

设ｆ「ｘ１，ｘ２，…，ｘｎ」是ｆ（ｘ）的ｎ－１阶差商。不需要任何解析的假设，我们给出方程ｆ「ｘ１，ｘ２，…，ｘｎ」＝ｈ（ｘ１＋ｘ２＋…＋ｘｎ）的一般解，解决了１９９２年Ｂａｉｌｅｙ提出的问题，另外，我们也给出两个其他多项式特征。     

两个关于某一二次微分系统的极限环个数的猜想的等价性

Ｊ．Ｗ．Ｗ雷恩教授猜想二次微分系统：ｘ＝－ｙ＋δｘ＋ｌｘ＾２＋ｍｘｙ，ｙ＝ｘ（１＋ｘ）在条件ｌ〉０，ｍ〉２，δ〈０之下最多只能有两个极限环，但无法证明。要本文证明了他的猜想和作者文「２」中的一个猜想是等价的。     

一多项式系统的极限环

讨论了系统ｄｘ／ｄｔ＝－ｙ（１＋ｙ）＾ａ＋ｄ·Ｘ＾ａ＋ｘ＾ａ＋１＋ｄｘ＾２ｙ ｄｙ／ｄｔ＝ｘ＾２（１＋ａｘ＋ｙ）的极限环。彻底解决了该系统极限环存在的个数和分布问题。讨论的结果包含了文「１」。（α为正的奇数）。     

二阶超前微分方程的振动性

建立了二阶超前微分方程「１／ａ（ｔ）ｘ‘（ｔ）」’＋ｐ（ｔ）ｘｃ（ｔ）＋ｑ（ｔ０ｘ（σ（ｔ））＝０的若干新的振动准则。     

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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