中立型线性微分—差分方程的稳定性

应用Ｌｉａｐｕｎｏｖ泛函法研究了［ｘ（ｔ）－Σｋｉ＝１Ａｉｘ（ｔ－τｉ）］′＝－Ｂ０ｘ（ｔ）－Σｋｉ＝１Ｂｉｘ（ｔ－τｉ）中立型微分－差分方程的稳定性，其中ｘ∈Ｒｎ，Ｂ０，Ａｉ，Ｂｉ（ｉ＝１，２，…，ｋ）皆为ｎ×ｎ阶实常阵，τｉ∈（０，＋∞）（ｉ＝１，２，…，ｋ）．得到了该方程平衡态稳定性的几个充分判据     

一类对称函数不等式的加强,推广及应用

ＥＫ（ｘ）,Ｅｋ（１－ｘ）和Ｅｋ（１＋ｘ）分别表示ｘ１,…,ｘｎ;１－ｘ１,…,１－ｘｎ和１＋ｘ１,…,１＋ｘｎ的第ｋ个初等对称函数,借助控制不等式理论中强和推广了关于对称函数的一类不等式的结论,主要结果为：１）（Ｃ＾ｋｎ－１）＾ｒ,ｓ＾ｒｋａ≤Ｅｋ（ｓ－ｘ＾ａ）－λＥ＾ｒｋ（Ｘ＾ａ）≤（Ｃ＾ｋｎ）ｓ＾ｒｈａ（（１－１／ｎ＾ａ）＾ｋｒ－λ（１／ｎ＾ａ）＾ｋｒ）,其中ｎ≥３,Ｘｉ〉０,ｉ＝１,…,ｎ     

关于高阶泛函边值问题的一个比较定理

考虑泛函边值问题：ｘ（ｎ）－ｎｉ＝１Ａｉ（ｔ，ｘ，ｘ，…，ｘ（ｎ－１）ｘ（ｉ－１）＝ｆ（ｔ，ｘ，ｘ，…，ｘ（ｎ－１））（０≤ｔ≤１），Ｂ（ｘ，ｘ，…，ｘ（ｎ－１））＝ξ．在适当条件下，利用Ｂｏｒｓｕｋ定理证明了上述问题的可解性蕴含于边值问题“ｘ（ｎ）－ｎｉ＝１Ｐｉ（ｔ）ｘ（ｉ－１）＝０，Ｂ（ｘ，ｘ，…，ｘ（ｎ－１））＝ξ”解的唯一性．     

时间序列引出的数学问题(Ⅱ)

Ｘ′＝（ｘ１，ｘ２…，ｘｎ），问在∑ｎｉ＝１ｘ２ｉ≤１条件下，ａ３＝∑ｎ－２ｉ＝１ｘｉｘｉ＋２，ａ５＝∑ｎ－１ｉ＝１ｘｉｘｉ＋１，当Ｘ取遍∑ｎｉ＝１ｘ２ｉ≤１上的点，（ａ３，ａ５）在平面上构成怎样的图形？该文对ｎ＝４给出解析解     

多滞量具有正负系数的一阶中立型时滞微分方程的稳定性

本文考虑一阶中立型时滞微分方程（１）：［ｘ（ｔ）＋Σ＾ｎ１ｉ＝１ｃｉ（ｔ）ｘ（ｔ－ｒｉ）］＾１＋Σ＾ｎ２ｋ＝１ｐｋ（ｔ）ｘ（ｔ－τｋ）－Σ＾ｎ３ｊ＝１ｑｉ（ｔ）ｘ（ｔ－σｊ）＝０的稳定性。这里ｐｋ（ｔ），ｑｉ（ｔ）∈Ｃ（［ｔ０，＋∞），Ｒ），γｉ，τｋ，σｊ均为非负实数，我们建立了此方程的一个稳定性结果，较文献［６］讨论得更广泛，所得结论更深刻。     

时间序列引出的数学问题（三）

若Ｘ′＝（ｘ１,ｘ２,…,ｘｎ）,问在ｎｉ＝１ｘ２ｉ≤１条件下,ａ３＝ｎ－２ｉ＝１ｘｉｘｉ＋２,ａ５＝ｎ－１ｉ＝１ｘｉｘｉ＋１,当ｘ取遍ｎｉ＝１ｘ２ｉ≤１的点,（ａ３,ａ５）在平面上构成怎样的图形．该文对ｎ＝５给出解析解．     

Lobesgue型函数的精确阶

给出λｎ（ｘ）＝ｎ／∑／ｋ＝１｜ｚ－ｘｈ｜＾ｚ｜ｌｋ（ｘ）｜＾ｔ和它的更广泛形式∧ｎ（ｘ）＝ｊｎ／∑／ｈ＝ｉｎ｜ｘ－ｘｋ｜＾ｓ｜ｌｋ（ｘ）｜＾ｔ的精确阶，它们分别是１／ｎ＾ｉ－１，其中，ｓ，ｔ是满足ｓ≥ｔ≥１的固定实数，１≥ｉｎ≥ｊｎ≥ｎ，ｍｎ＝ｊｎ＝ｉｎ＋１。     

关于高阶泛函数值问题的一个比较定理

考虑泛函边值问题：ｘ＾（ｎ）－ｎ／∑／ｉ＝１Ａｉ（ｔ，，ｘ，ｘ′，…，ｘ＾（ｎ－１））ｘ＾（ｉ－１）＝ｆ（ｔ，ｘ，ｘ′，…，ｘ＾（ｎ－１）（０≤ｔ≤１），Ｂ（ｘ，ｘ′，…，ｘ＾（ｎ－１）＝ξ。在适当条件下，利用Ｂｏｒｓｕｋ定理主明了上述问题的可解性蕴含于边值问题：ｘ＾（ｎ）－ｎ／∑／Ｐｉ（ｔ）ｘ＾（ｉ－１）＝０，Ｂ（ｘ，ｘ′，…，ｘ＾（ｎ－１）＝ξ”解的唯一性。     

实对称矩阵逆特征值问题的可解条件

该文考察以下２个逆特征值问题（１）问题（ＳＡ）；设Ａ＝（ａｉｊ）为ｎ阶实对称矩阵，其主对角元ａｉｊ＝０，ｉ＝２，．．．．ｎ，给定时角矩阵Ａ＝ｄｉａｇ（λ１，λ２，．．．．λｎ）∈Ｒ＾ｎ×ｎ，求一实时对角矩阵Ｘ＝ｄｉａｇ（ｘ１，ｘ２，．．．．ｘｎ）∈Ｒ＾ｎ×ｎ，使λ（Ａ＋Ｘ）＝λ（Ａ），（Ⅱ）问题（ＳＭ）：设Ａ（ａｉｊ）为ｎ阶实时对称矩阵，其主对角元ａｉｊ＝１，ｉ＝１，２，．．．．ｎ。给定对角矩阵Ａ     

一类非线性泛函边值问题

考虑形如“ｘ（ ｎ） － ∑ｎｉ＝１Ａｉ（ｔ） ｘ（ｉ－ １） ＝ ｆ（ｔ,ｘ,ｘ′,…,ｘ（ ｎ－ １）） 　（０ ≤ｔ≤１） ,Ｂ（ ｘ,ｘ′,…,ｘ（ ｎ － １）） ＝０”的非线性泛函边值问题,利用基于度理论的不动点定理,给出了上述边值问题有解的某些充分条件．     

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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