一类初等算子的范数

目的讨论B(H)上初等算子Δ(X)=AXB CX的范数。探求‖Δ‖=‖A‖‖B‖ ‖C‖(A,B,C≠0)成立的充要条件和‖Δ‖的下界。方法以正规极大数值域这一复数域上的紧凸子集为媒介,根据其定义及初等算子范数的性质推导。结果‖Δ‖=‖A‖‖B‖ ‖C‖(A,B,C≠0)成立的充要条件是‖A*C‖=‖A‖‖C‖且WN(A*C)∩WN(B)≠。并求出‖Δ‖≥supλ∈WN(B)‖‖B‖A -λC‖。结论得到有关初等算子Δ范数上界的一个充要条件,找到了初等算子Δ范数的下界。并且得到初等算子范数的一些推论。     

Bloch空间上的广义Cesaro算子的本性模

H（B）是单位球B上的全纯函数的全体,对g∈H（B）,讨论了Bloch空间上的广义Cesàro算子Tg的本性模估计.利用上极限,给出了‖Tg‖e,B→B的表示.此处‖Tg‖e,B→B表示Bloch空间上的广义Cesàro算子的本性模.     

关于Fourier部分和算子范数上下界的新估值

研究Fourier算子Sn的范数‖Sn‖=1π∫π-π|sin2n 1/2t/2sint/2|dt.已知‖Sn‖具有表达式‖ Sn‖=4/π2 log n A n,其中A n表示与n相关且对n一致有界的数列.至今最好的估计是Rivlin给出的:‖Sn‖≤4/π2 log n 3,通过进一步精细的估计证明了4/π2 log n 1《‖Sn‖《4/π2 log n 2,从而给出了关于一致有界量An的上下界的一个新估计.     

对称自正交相似矩阵反问题的最小二乘解

通过给出对称自正交相似矩阵的表示定理,研究了如下对称自正交相似矩阵反问题:问题Ⅰ:己知X、B∈Rn×m,Jn×n为全体n阶对称自正交相似矩阵的集合,n=2k.求A∈Jn×n,使得‖AX-B‖=min.问题Ⅱ:已知A*∈Rn×n,SE是问题Ⅰ的解集.求∈SE,使得‖A*-‖=infA∈SE‖A*-A‖.给出了问题Ⅰ的解的通式及问题Ⅱ的惟一解的表达式.     

关于亚正规算子的Hilbert-Schmidt范数不等式

设H为可分无限维Hilbert空间,(T_1,T_2)和(S_1~*,S_2~*)分别为H上重交换的亚正规算子对及次正规算子对,则对任X∈B(H),不等式‖T_1XS_1+T_2XS_2‖_2≥‖T_1~*XS_1~*+T_2~*XS_2~*‖_2都成立;若T,S~*为亚正规算子且‖T‖~2-T~*T为迹类算子,则不等式‖TX-XS‖_2≥‖T~*-XS~*‖_2对任意X∈B(H)都成立。     

算子代数上保持高维数值域的映射

令B （H）是复Hilbert空间H上所有有界线性算子组成的代数,k是一个正整数且满足kk（A）表示算子A∈B （H）的k-维数值域。假设φ：B （H）→B （H）是满射。文章证明了φ满足W_k（AB-ξBA）=W_k(φ（A）φ（B）-ξφ（B）φ（A）)（ξ为不等于±1的复数）对所有A,B∈B （H）成立当且仅当存在酉算子U∈B （H）以及常数η∈{-1,1}使得φ（A）=ηUAU*对所有A∈B （H）成立;φ满足W_k（BA*B）=W_k(φ（B）φ（A）*φ（B）)对任意A,B∈B （H）成立当且仅当或者存在酉算子U:H→H使得φ（A）=UAU*对所有A∈B（H）成立,或者存在共轭酉算子U:H→H使得φ（A）=UA*U*对所有A∈B（H）成立。     

自伴算子的几个重要范数不等式

R．Nakamoto证明了范数不等式‖e^iH-I‖≤‖H‖对于任意的H∈B(H）是自伴算子都成立．该文给出了它的另一种证明，同时应用算子分解和函数演算，证明了复Hilbert空间上的自伴算子的几个重要范数不等式。     

自伴算子空间上保持Jordan积范数的映射

设H是复数域C上的Hilbert空间且dimH≥2,Bs(H)是H上所有自伴算子全体。设Φ是Bs(H)上的双射,如果Φ满足对任意A,B∈Bs(H),都有‖Φ(A)Φ(B)+Φ(B)Φ(A)‖=‖AB+BA‖,则存在一个酉算子或反酉算子U和泛函h:B(H)→{1,-1}使得对任意X∈B(H),有Φ(X)=h(X)UXU*。     

关于算子矩阵的谱补问题

设H-和H为可分复Hilbert空间，对定义在Hilbert空间 上的缺项算子补矩阵M（A，B，C，X），其中A∈B（H-），B∈B（H），C∈B（H，H-）给定。当三元算子对（A，B，C）满足一定条件时，X取遍B（H-，H）中算子时，利用构选算子的方法，给出算子补矩阵M（A，B，C，X）的谱之交的结果以及其谱配置结果。     

线性流形上一类双结构矩阵反问题的最小二乘解

设 J=[-0In I0n]In是n阶单位辛矩阵,若A∈C2n×2n满足AHA=I2n,AHJA=J,则称A为辛酉矩阵,所有2n阶辛酉阵的全体记为SUC2n×2n.令S={A∈SUC2n×2n|‖AY-Z‖=min,Y, Z∈C2n×p},本文考虑如下问题:问题Ⅰ给定X,B∈C2n×m,求A∈S使f(A)=‖AX-B‖=min.问题Ⅱ给定～A∈C22n×2n,求～A∈SE使得‖～A-～A‖=infA∈SE‖～A-A‖,其中SE是问题Ⅰ的解集合.本文给出了解集SE的通式及逼近解～A的表示式和一些有关的结果,并给出了相应的数值算法.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the