关于半对称度量联络(Ⅰ)

n维光滑流形M~n,其上给定一光滑线性管络V,其挠率T(X Y)=▽_AY ▽_YX-[XY]满足关系式T(XY)=π(Y)X-π(X)Y (1) 这里X,Y分别为M~n上两任意光滑切向量场,而π是指定的光滑(?)形式,这种联络称为半对称的。此外M~n上给予一黎曼结构(M~ng),自然诱导出黎曼联络,无挠率。如果上述半对你联络▽又是度量的,即▽g=0,那么称▽为半对称度量联络。在M~m上存在两     

关于半对称度量循环联络

对黎曼流形上的半对称度量循环联络引进截面曲率和迷向的概念,证明了黎曼流形M~n(n>2)容有迷向半对称度量循环联络的充要条件是M~n为共形平坦的,讨论了半对称度量循环联络在子流形上的诱导,得到半对称度量循环联络在子流形上的诱导亦是半对称度量循环联络。     

黎曼流形上半对称度量联络的一些性质

讨论了黎曼流形上半对称度量联络与黎曼联络之间的关系,得到了它们有相同射影曲率张量的充要条件,而且证明了黎曼流形上的半对称度量联络是迷向的,当且仅当它是射影平坦的,这可以认为是贝尔特拉米定理的推广。     

容有S-共圆联络的黎曼流形的几个性质

Stavre P.(1982)给出了容有S-共圆联络的黎曼流形上联络D与黎曼联络■的变换关系.本文在此基础上进一步得出了容有S-共圆联络的黎曼流形的几个性质.     

正定矩阵流形上的Jacobi场

讨论了正定矩阵流形D(n)的几何结构.新定义其上的黎曼度量,给出了流形 D(n)上的黎曼联络和黎曼曲率张量.从微分几何的角度,研究流形 D(n)上的Jacobi场,进而考虑测地线的收敛性,并举例说明结果.      

具有1/4对称度量联络的黎曼流形的超曲面

定义两种特殊的１／４对称度量联络,证明了这些联络在黎曼流形的超曲面上的诱导联络仍然是１／４对称度量联络,给出了关于这些联络的Ｇａｕｓｓ,Ｗｅｉｎｇａｒｔｅｎ公式和Ｇａｕｓｓ,Ｃｏｄａｚｚｉ方程,同时也得到了具有这些联络的黎曼流形超曲面的某些性质。     

关于黎曼流形的曲率张量

在Contact黎曼流形上讨论了关于联络↓Δ^-的截面曲率及相关的几个等价条件，并在此基础上给出了联络↓Δ^-的曲率张量与数量曲率的公式．证明了在Contact黎曼流形(M．η．g)上，Bocher型曲率张量是Gauge变换的不变量当且仅当对应的Contact-Riemanian结构是可积的．     

半对称度量联络的一些性质

讨论了黎曼流形上半对称度量联络与黎曼联络张量之间的关系,令半对称度量联络的特征张量和黎曼联络的度量张量成比例,则张量之间的关系简化,进而得到了一些新的性质。     

拟常曲率黎曼流形中的法联络平坦子流形

研究了拟常曲率黎曼流形中的法联络平坦子流形，将常曲率黎曼流形中B.Y.Chen和M.Okumura关于数量曲率和截面曲率关系之间一个著名不等式推广到环绕空间是拟常曲率黎曼流形的情形，作为应用，简捷地将M.Okumura的两个重要结果推广到这种环绕空间中法联络是平坦的子流形上去。     

常数量曲率黎曼度量之共形形变

本文考查光滑黎曼流形(M^n,g)(n≥2)的共形形变．证明了如下结论：存在共形于度量g的黎曼度量g^-使得g^-的曲率R^-等于一个事先给定的函数K．     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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