广义极分解的扰动等式

研究m×n(m≥n)且秩为r的复矩阵A的广义极分解A=QH,其中Q为m×n次酉矩阵,H为n×n半正定矩阵;利用奇异值分解的方法,给出了在任意酉不变范数下Q和H的扰动等式.     

(次) 酉极因子扰动界的一些注记

设A是m×n复矩阵,分解式A=QH称为A的广义极分解,如果Q是m×n次酉矩阵和H是n×n半正定的Hermite矩阵.本文改进了以往的(次)酉极因子的扰动界.     

M-P逆在加法扰动下半正定极因子的扰动界

设A∈Cmr×n,~A∈Cmr×n,则A+∈Crn×m,~A+∈Cnr×m.A+和~A+的广义极分解分别是A+=QH与~A+=~Q~H,其中H与~H为n×m次酉矩阵,利用奇异值分解的方法,给出了Moore-Penrose广义逆矩阵A+在酉不变范数‖.‖下半正定极因子的扰动界.     

M—P逆在加法扰动下半正定极因子的扰动界

设A∈Cm×nr,(A)∈Cm×nr,则A+∈Cn×mr ,(A)+∈Cn×mr.A+和A+的广义极分解分别是A+=QH与(A)+=(QH),其中H与(H)为n×m次酉矩阵,利用奇异值分解的方法,给出了Moore-Penrose广义逆矩阵A+在酉不变范数‖·‖下半正定极因子的扰动界.     

半正定极因子在酉不变范数下的绝对与相对扰动界

设A=QH是矩阵ACm×n的极分解,其中Q*Q=I,I为n阶单位矩阵,H为n阶Hermite半正定矩阵.给出了任意扰动下Hermite半正定极因子在酉不变范数下的绝对与相对扰动界.对于满秩矩阵,绝对与相对扰动界具有最优性质.     

矩阵乘积与数值域性质的推广

设A为一个n×n矩阵,σ(A),W(A)分别表示A的谱集和数值域.若对任意n×n酉矩阵U有σ(AU)■W(A)W(U),那么A为数乘半正定矩阵,从而改进和推广了一些相关的结果.     

关于完全正矩阵分解指数的注记

一个n×n阶的元素非负矩阵A称为双非负的,若A还是半正定矩阵,A称为完全正矩阵,如果A可以分解成 A=BB′,其中矩阵B为某个非负的n×m矩阵,m为某个自然数.这种所有可能的最小的自然数m称为矩阵A的分解指数(或称为A的CP-秩).1994年,Drew,Johnson 以及Loewy等人提出著名的DJL-猜想:对于任意一个n阶完全正矩阵A,有:CP-rank(A)≤[(n2)/(4)].本文证明了在n=5以及n=6时的特殊情形下此猜想成立.     

复矩阵的对称满秩分解

在矩阵的正交三角分解、奇异值分解的基础上,给出了复矩阵的Hermite标准形的求解方法,得到了将复矩阵分解为一个酉矩阵和Hermite半正定矩阵的乘积,以及分解为满秩矩阵与幂等矩阵之乘积的方法.证明了复方阵可分解为一个复对称矩阵与一个复对称满秩矩阵之积.进一步给出了复满秩阵分解为两个Hermite酉矩阵与正定阵之积的方法.     

实对称半正定矩阵的三角(LLT)分解

设A为n阶实对称半正定矩阵,若存在一个对角线上元素全为非负的下三角阵L,使A=LLT,称为对A的三角分解.本文讨论了实对称半正定矩阵的三角分解的存在性以及这种分解的唯一性的充要条件,最后给出了实对称半正定矩阵的三角分解的一种算法.     

关于计算M—P逆的一种直接法的注记

计算一个m×n(m≥n)矩阵A的M—P广义逆A~ 的一类直接方法,是将A进行正交化分解: A=QU,其中Q是m×r矩阵且Q~*Q=Ⅰ,U是r×n上梯形阵,这里r是矩阵A的秩。则A~ =U~ Q~(?)。当     

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