局部对称伪黎曼流形中2-调和类空子流形的刚性

局部对称伪黎曼流形中2-调和类空子流形的刚性性质被研究。通过活动标架法和Hopf原理,证明了这类子流形在常平均曲率或者紧致的情况下是极大的,得出两个刚性定理,改进了相关结果。     

黎曼流形上Fritz John必要最优性条件

在黎曼流形上给出了Lipschitz函数的广义方向导数和广义梯度的概念,利用黎曼流形局部上与欧氏空间开集微分同胚的性质以及切映射和余切映射导出了广义梯度的性质和运算法则,证明了定义在黎曼流形上的函数取得极小值的必要条件是广义梯度包含零元素,并利用这些性质给出了黎曼流形上数学规划问题的Fritz John型最优性条件.     

局部对称伪黎曼流形中的2-调和类空子流形

本文研究了完备连通的局部对称伪黎曼流形中的2-调和类空子流形,应用Green散度定理,得到了这类子流形广义的J.Simons型积分不等式及某些内蕴刚性定理,推广了已有的结果。     

黎曼几何学思想的渊源 ——几何、物理与哲学的视角

将几何、物理与哲学作为一个整体来考察,探究黎曼几何学思想的渊源。以空间概念的历史为切入点,分析梳理赫尔巴特哲学方法论对黎曼几何学构想的影响;揭示高斯的几何学思想与黎曼几何学的内在关联;从经典力学的Lagrange方程出发,通过变分方法,揭示了物理学与几何学之间的内在联系。     

黎曼流形上的刘维尔定理

通过研究完备的、Ricci曲率非负的黎曼流形上的次调和函数的性质,给出了Yau的关于黎曼流形上的刘维尔定理的另一证明.     

高斯的内蕴微分几何与非欧几何

目的分析与研究高斯关于非欧几何的研究和内蕴微分几何思想之间的联系。方法文献分析研究和数学史比较研究。结果总结分析了高斯建立的内蕴微分几何的思想和渊源,揭示了其与非欧几何学的内在联系。结论高斯于1827年发表的《关于曲面的一般研究》,一方面奠定了内蕴微分几何的基础,同时也以其独特的“高斯风格”将自己的非欧几何研究揭示于众。     

基于黎曼流形上的非可微规划问题的必要最优性条件

针对黎曼流形上的非可微数学规划问题,在黎曼流形上分别给出了Lipschitz函数的广义方向导数和广义梯度的概念.利用黎曼流形局部与欧氏空间开集微分同胚的性质,把定义在线性空间上的广义方向导数和广义梯度的性质和运算法则通过切映射传递到流形的切空间上去.在此基础上,利用Ekeland变分原理,推导出基于黎曼流形上具有等式和不等式约束的数学规划问题的必要最优性条件.     

伪黎曼空间型的2-调和类空子流形

研究伪黎曼空间型的2-调和类空子流形, 通过计算, 获得了这种子流形上一个Simons型积分不等式. 对该子流形进行一定限制, 使其成为极大类空子流形, 再利用Simons型积分不等式, 分别讨论了外围空间伪黎曼空间型截面曲率为正、负或零时子流形的各种性质, 得到了一系列结果.     

蒙日和高斯微分几何思想的比较研究

目的系统探讨和分析蒙日几何学派和高斯几何学派的微分几何思想。方法历史分析、比较研究和文献考证。结果曲面可以用立体的边界与孤立的二维薄膜两种方式验证。前者是制图工程师看待曲面的方式,属于蒙日几何学派的观点;后者是测地员考虑方式,属于高斯几何学派的观点。结论蒙日几何学派和高斯几何学派相辅相成,推动了微分几何的发展。     

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.     

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