S3到CP4中的等变极小浸入

研究复射影空间CP4中常曲率的等变极小3维球面S3=SU（2）,结果表明这种浸入若不是弱Lagrangian浸入,则其截面曲率C≤1。     

具非负曲率的完备非紧黎曼流形

将三维欧式空间旋转抛物面顶点的定义推广到一般的非负曲率完备非紧黎曼流形上,利用Perelman G证明Cheeger-Gromoll核心猜想的几何方法,讨论了具非负曲率的完备非紧黎曼流形M上的核心S的结构, 证明了如果由核心出发的法测地线均为射线,则或者S退化为一点,或者M=Rk×N,其中N是紧致的具非负曲率的黎曼流形.特别地,如果核心的维数仅比流形的维数低一维,可以证明其法测地线均为射线,从而有M=Rn-1×S.     

复投影空间的正曲率Kaehler子流形

复投影空间的各种流子形在近年内讨论得较多。本文只涉及具有正曲率的Kaehler子流形。在这方面,已有邱成桐和K.0giue的结果。 设P_(n p)(C)是具有Fubini—Study度量的复n p维投影空间,它的常全纯截面曲率c=1。设M_n是P_(n p)(C)的复n维紧致Kaehler子流形。分别以K、H、S表示M_n的截面曲率、全纯截面曲率和Ricci曲率。 〔1〕的结果是:     

S~3到CP~4中的常曲率等变极小浸入

研究常曲率的3维球面S3到复射影空间CP4中的等变极小浸入,研究结果表明这种浸入只能是弱Lagrangian浸入,从而是全测地的。     

具有Ricci曲率平行空间中2-调和超曲面

以Nn+1表示其截面曲率KN满足条件a≤KN≤b的n+1维单连通完备Riem ann流形,且Ricci曲率平行,Mn是Nn+1中的2-调和超曲面,本文给出这类超曲面关于其第二基本形式模长平方S的积分不等式及刚性定理。     

S3到CP4中的常曲率等变极小浸入

研究常曲率的3维球面 S3到复射影空间 CP4中的等变极小浸入，研究结果表明这种浸入只能是弱Lagrangian浸入，从而是全测地的。     

单位球面低维子流形的Pinching定理

设M是n p维单位球面S~(n p)的n维紧致子流形,n=2,3,4;M具有平行平均曲率向量,若M的第二基本形式长度的平方S≤(2/3)n处处成立,则M是全脐点的或Veronese曲面。     

球面中的紧致极小子流形

<正>对于球面中的紧致极小子流形,一个基本的问题是它具有什么样的性质?S.T.Yau在[1]中从截面曲率的角度,讨论了这个问题,N.Ejiri[2]从Ricci曲率的角度研究了这种子流形,得出:“设M是一浸入在n+p维球面S~(n+p)中的n维单连通紧致定向的极小子流形,且其浸入是满的,如果n≥4,且M的Ricci曲率≥n-2,则M或是全     

Kropina度量的一些射影性质及曲率性质

讨论Kropina度量的射影性质及曲率性质,得到:Kropina度量成为Douglas度量当且仅当β是闭的1形式.计算Kropina度量的S曲率并得到其具有几乎迷向S曲率及常S曲率的条件.     

关于拟常曲率空间中具有常平均曲率超曲面

设(Nn 1,g)是n 1维单连通完备的黎曼流形,其黎曼曲率张量取如下形式KABCD=a(gACgBD-gADgBC) b(gACλBλD gBDλAλC-gADλBλC-gBCλAλD), ∑gABλAλB=1,称Nn 1为拟常曲率空间.本文讨论了这类空间中具有常平均曲率的紧致超曲面,给出了关于其第二基本形式模长平方S的积分不等式.     

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