局部对称空间中的紧致极小子流形

研究了局部对称的黎曼流形N^n＋p中的紧致极小子流形M^n,推广了这类子流形中已有的结果,得到了与子流形的第二基本形式模长的平方口有关的Pinching定理。     

局部对称空间中伪脐子流形的Pinching定理

研究了2个嵌套空间中子流形,对于局部对称空间中的常曲率黎曼子流形以及常曲率黎曼子流形中具有平行平均曲率向量的紧致伪脐子流形,给出了这种伪脐子流形是全脐子流形的两个充分条件.     

局部对称共形平坦黎曼流形中的伪脐子流形

研究了局部对称共形平坦黎曼流形中具有平行中曲率向量的紧致伪脐子流形,得到了这类子流形的两个内蕴刚性定理,从而推广了文献[1]中的结果。     

局部对称黎曼流形中极小子流形的截面曲率的pinching问题

讨论了局部对称黎曼流形中的紧致极小子流形,得到了这类子流子形有关截面曲率的一个pinching定理,推广了Y.S.T的球面中紧致极小子流形的有关截面曲率的pinching条件.     

局部对称共形平坦黎曼流形的极小子流形

设Ｍ是局部对称共形平坦黎曼流形的紧致极小子流形。Ｋｃ和Ｑ分别是Ｍ上每点截面曲率和Ｒｉｃｃｉ曲率的下确界，Ｒ是Ｍ的数量曲率。本文利用三种内在量Ｋｃ，Ｑ和Ｒ所满足的适当关系，刻划了这种子流形是全测地子流形的充分条件。     

局部对称空间中关于截面曲率的一个刚性定理

设Nn p是截面曲率K满足12<δ≤KN≤1的n p维局部对称完备黎曼流形,M是N的具有平行平均曲率向量的n维紧致子流形,我们讨论这类子流形,得到其关于截面曲率拼挤定理,将常曲率空间中的类似问题推广到局部对称空间。     

局部对称空间中具有平行中曲率向量的子流形

研究了局部对称黎曼流形中具有平行中曲率向量的子流形,给出了一个与子流形的截面曲率、平均曲率及余维数有关的夹挤定理。     

局部对称空间中的紧致极小子流形的Ricci曲率

设N^m＋p是截面曲率KN满足1/2〈δ≤KN≤1的n＋p维局部对称空间完备的δ-Pinching黎曼流形,M^n是N^m＋p中的紧致极小子流形。讨论了这类子流形关于Ricci曲率的pinching问题。     

局部对称空间中关于第二基本形式模长平方的一个刚性定理

设N^n＋p是截面曲率KN满足1／2〈δ≤KN≤1的n＋p维局部对称完备黎曼流形，M^n是N^n＋p的具有平行平均曲率向量的n维紧致子流形，我们讨论这类子流形，得到其关于第二基本形式模长的平方、及余维数减小的刚性定理，将常曲率空间中的类似问题推广到局部对称空间。     

局部对称空间中的极小子流形

Yau研究了常曲率空间中的紧致极小子流形,获得一个与Simons不等式类似的结果,该文将类似问题推广到局部对称空间中,得到了相关结论.     

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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