一类Riccati方程解法的研究及推广

研究一类Riccati方程的可积性，给出其解法.通过变量求异方法，构造Riccati方程新变量的Bernoulli微分方程，间接求解Riccati方程.结果：对于无法表达成显式形式的Riccati方程给出隐式解以及给出隐式解存在的条件.将具体无法表达成显式形式的Riccati方程的求解，推广为一类Riccati方程求解的形式.     

Riccati方程的广义反射函数与周期解

为了解决Riccati方程的周期解与稳定性,提出了通过Riccati方程的广义反射函数来寻找其Poincaré映射的方法。结果表明:从微分系统的广义反射函数角度出发,得到了Riccati方程具有线性广义反射函数的条件,从而推出了Riccati方程的线性广义反射函数,得到了Riccati方程的Poincaré映射,以及Riccati方程有周期解的条件与稳定性。由于通过广义反射函数寻找Poincaré映射比较简单可行,所以,Riccati方程的周期解与稳定性的研究成果对其它微分系统的研究也具有指导作用。     

Riccati方程及其幂级数解法

通过定理2和定理3，建立了Riccati方程和二阶齐线性微分方程的关系，并利用二阶齐线性微分方程的幂级数解表示相应Riccati方程的解。     

Riccati微分方程解的探讨

Riccati微分方程是一类几乎没有初等解的简单的微分方程。但当其系数满足某些特殊条件时,原Riccati微分方程是有初等解的。本文主要依据Liuville提出的特解变换化Riccati微分方程为Bernoulli方程,进而求得原方程的通解的思想,从Riccati微分方程的系数特征、相互间的关系出发,通过归纳、总结,得出一系列Riccati微分方程的特解的求解方法;并与特解变换相联系,使之成为解某些特殊Riccati微分方程的效手段;同时对Liuville所提出的特解变换进行推导、延伸,从而求得某些特殊Riccati微分方程的更多的通解表达式。     

推广的Riccati方程可积的若干充分条件

非线性的Riccati方程y二P（X）y‘＋Q（X）y＋R（X）（1）是由研究声学的威尼斯的JacopoFranceseoRiccati｛A爵（1676～1754）首先引进的,这之后数学家D．Bernoulli和J．Liouville等先后进行了研究。我国数学家秦元勋曾于1979年探讨了它是否具有周期与稳定解的问题。鉴于Riccati方程在一般情形下不具有初等可积的条件,至今还有许多人在研究它,Riccati方程之所以受到重视,是因为它可用于帮助求解二阶常微分方程。文献【川中给出了Riccati方程具有初等解的5个充分条件,本文将在此基础之上,将其结论进行推广,研究形如y一月（x）…     

关于Riccati方程的一个结论

给出周期系数Riccati方程存在周期解的一个充分条件,该条件涵盖了Riccati方程存在周期解的两个经典定理. 还给出了Riccati方程周期解不存在的一个充分条件. 举实例说明它们具有更广的适用性.     

一类有初等函数解的Riccati方程

本文利用广义的Bessel方程及其解给出了一类有初等函数解的Riccati方程．     

某些黎卡蒂(Riccati)方程的解

Riccati方程的解一般是不能用初等函数给出的.本文给出了一般的Riccati方程几个重要的性质,若已知Riccati方程特解,则利用变量变换可将其化为可求解的微分方程,进而得到它的通解.     

偶数阶中立型差分方程的振动性

研究了偶数阶非线性中立型差分方程△^m-1(αn△(xn pnxιn)) f(n,xgn)=0的振动性，通过对其最终正解作Riccati变换，得到相应的Riccati型差分不等式，并由此得到若干个该方程所有解的振动准则。     

二维Klein-Gordon-Zakharov方程的显示精确解

利用Riccati方程的形式解,采用齐次平衡法的思想求二维Klein-Gordon-Zakharov方程的显示精确解.借助Maple的符号计算功能,得到了二维Klein-Gordon-Zakharov方程的孤波解、周期解和有理解,并给出了其孤波解的数值模拟图形.     

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.     

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