具非负曲率完备非紧黎曼流形的闭测地线

Kingenberg证明了任意紧致黎曼流形上都存在闭测地线,Yau提出是否能够证明紧致黎曼流形上有无穷多条闭测地线.由著名的Cheeger-Gromoll的核心结构的思想,任意的具非负曲率完备非紧的黎曼流形与它的核心是同伦等价的.因此可以考虑具非负曲率完备非紧的黎曼流形闭测地线存在性和分布性问题.本文证明了当核心的余维数是奇数且具非负曲率的完备非紧的黎曼流形上存在有无穷多条闭测地线;并由此讨论了紧致的非单连通黎曼流形上无穷多的闭测地线存在性问题.     

非负曲率的完备黎曼流形上的平行射线

讨论了具非负典率的完备非紧黎曼流形M上平行射线的性质,证明了此时两平行射线对应于M上的同一个Busemann函数.同时证明了具完全平行性质的非负曲率的完备非紧黎曼流形M=Rk×S,其中S为核心.     

关于黎曼几何若干问题

总结了完备黎曼流形上完备的无共轭点测地线所隐含的几何性质、完备非紧具非负曲率黎曼流形的几何结构、完备非紧具非负Ricci曲率黎曼流形的几何拓扑性质以及完备非紧黎曼流形上的Busemann函数所隐含的几何拓扑性质,并提出了一些未解决的问题．     

具非负曲率的黎曼流形

利用沿测地线的Ｊａｃｏｂｉ场和指标形式，证明了具非负曲率的完备２维黎曼流形Ｍ＾２如果没有共轭点，必等距于Ｒ＾２。     

具非负Ricci曲率的流形

讨论了具非负Ricci曲率的完备Riemann流形上的无共轭点测地线的性质,证明了单连通具拟正Ricci曲率的三维完备非紧Riemann流形的第一Betti数b1≤n—3。     

具非负曲率的完备黎曼流形上核心的性质

讨论了具非负曲率的完备非紧黎曼流形上的核心的结构,证明了如果核心是惟一的,那么核心将退化为极点.     

具非负Ricci曲率的完备非紧黎曼流形

几何学研究的一个中心问题是曲率与拓朴性质之间的关系.本文讨论了具非负Ricci曲率的完备非紧黎曼流形的体积增长与其拓扑性质之间的关系.通过对测地球内的由球心点出发的最短测地线集合的测度与非最短测地线的测度的比较分析,根据距离函数临界点理论所隐含的拓扑性质,在大体积增长的情况下,得到流形拓扑的有限性.     

局部对称空间上的闭测地线

讨论了曲率定号的完备黎曼流形上的平行向量场与Jacobi场之间的关系；证明了紧致的偶数维具非负曲率的非单连通局部对称空间上存在无穷多条长度一样的闭测地线．     

完备黎曼流形上的Jacobi场

证明了在具非负曲率完备黎曼流形上，沿无共轭点测地线的正常平行向量场必为Ｊａ－ｃｏｂｉ场．     

只有一个B－函数的完备非紧具非负曲率流形

证明了只有一个Ｂ－函数的完备非紧具非负曲率之黎曼流形与Ｒ＾ｎ微分同胚。     

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