次Hermite矩阵的次正定性

若ｎ阶次Ｈｅｒｍｉｔｅ矩阵Ａ，对任意非零向量Ｘ＇＝（ｘ＿１，ｘ＿２，…ｘ＿ｎ）∈Ｒ￣ｎ，有ＡＸ＞０，则称次Ｈｅｒｍｉｔｅ矩阵Ａ是次正定的．给出了判定次Ｈｅｒｍｉｔｅ矩阵次正定的几个充要条件：定理ｎ阶次Ｈｅｒｍｉｔｅ矩阵Ａ是次正定的，当且仅当下列条件之一成立：（ｌ）Ｈｅｒｍｉｔｅ矩阵ＪＡ是正定的；（２）存在ｎ阶可逆复矩阵Ｐ，使ＡＰ＝Ｊ；（３）次Ｈｅｒｍｉｔｅ矩阵Ａ的４ｋ阶，４ｋ十互阶下次主子式为正，４ｋ＋２阶，４ｋ＋３阶下次主子式为负；（４）存在ｎ阶可逆复矩阵Ｐ，使其中λ＿ｉ＞０，ｉ＝１，２，…，ｎ。     

关于矩阵迹的几个不等式

设Γ＿１为对角线元素按减序排列的非负对角形矩阵，Ｕ＿１是酉矩阵，ｉ＝１，２，…，ｍ，则有当Ａ＿１，Ａ＿２．…，Ａ＿ｍ为半正定Ｈｅｒｍｉｔｅ矩阵时，有其中Γ＿１＝ｄｉａｇ（σ＿１（Ａ＿１），σ＿２（Ａ＿ｉ）．……σ．（Ａ＿ｉ））．ｉ＝１，２．…，ｍ。     

A′da′m循环图

若对任意的与ｎ互素的整数λ，都有〈λｊ＿１，λｊ＿ｒ，…，λｊ＿ｒ〉＝〈ｊ＿１，ｊ＿２，…，λ＿ｒ〉，则称循环图Ｃ＿ｎ〈ｊ＿１，ｊ＿２，…，ｊ＿ｒ〉为Ａ′ｄａ′ｍ循环图。本文给出了一个循环图Ｃ＿ｎ〈ｊ＿１，ｊ＿２，…ｊ＿ｅ〉为Ａ′ｄａ′ｍ循环图的充要条件以及ｎ阶Ａ′ｄａ′ｍ循环图的个数的计算公式。     

关于图B（m,n）的优美性

证明了：当ｍ≡１或２（ｍｏｄ４）时，Ｂ（ｍ，ｎ）＝Ｃ＿ｍ∪Ｐ＿ｎ是优美图，其中Ｃ＿ｍ＝Ａ＿１Ａ＿２…Ａ＿ｍＡ＿１，Ｐ＿ｎ＝Ａ＿１Ｂ＿１Ｂ＿２…Ｂ＿ｎ（ｍ≥３，ｎ＞０）。     

矩阵的一个定理和线性方程组解的结构

设Ａ∈Ｍ＿（ｍ×ｎ）（Ｆ），则存在ｍ阶可逆矩阵Ｐ和ｎ阶可逆矩阵Ｑ，使其中ｒ＝Ｒ（Ａ）；本文还讨论了一般线性方程组Ａ＿（ｍｎ）Ｘ＿（ｎ１）＝ｂ＿（ｍ１）的可解性及解的结构与矩阵Ｐ，Ｑ之间的关系。     

一道数学竞赛题的推广

记Ｂ是由１，２，…，ｎ的循环排列组成的集合，Ａ＿３（ｎ）＝ｍａｘｍｉｎ（ａ＿（ｉ＋１）＋ａ＿（ｉ＋２）＋ａ＿（ｉ＋３）），其中ｉ＝０，１，２，…．ｎ－１，ａ＿（ｎ＋１）＝ａ＿１，ａ＿（ｎ＋２）＝ａ＿２；ａｉ取１．２，…，ｎ中的任意值，ｉ＝１，２，…，ｎ．本文讨论了Ａ＿３（ｎ）的上界：除ｎ＝３，５．６外，当３｜ｎ－１时，Ａ３（ｎ）≤　；当３｜ｎ时，Ａ３（ｎ）≤　；当３｜ｎ＋１时．Ａ＿３（ｎ）≤．     

分块矩阵的初等变换和合同变换

分块矩阵的初等变换和合同变换江佑民（抚州师专数学系）投Ａ是数域Ｆ上，ｎ×ｎ的矩阵，将Ａ分成分块矩阵，并设Ａ的行的分法与列的分法一致，其中，Ａ＿（ｉｊ）为Ｆ上，ｎ＿ｉ×ｎ＿ｊ矩阵，ｎ＿１＋ｎ＿２十…＋ｎ＿ｓ＝ｎ。定义下面的变换称为分块矩阵的初等变换。１...     

圈Cn的道路多项式

道路多项式Ｐ＿ｋ（λ）是上，下对角线元素为１，其余位置元素为０的ｋ阶方阵的特征多项式，ｋ≥１和Ｐ＿０（λ）＝１。若Ｐ＿ｋ（Ａ）≥０，ｋ＝０，１，２，…，则说ｎ阶方阵Ａ是道路正矩阵。当图的邻接矩阵是道路正矩阵时，则称这个图是道路正图。该文给出了圈Ｃ＿ｎ的邻接矩阵的道路多项式计算公式。证明它是道路正图。     

n维Oppenheim不等式及其应用

设ａ＿ｉ（ｉ＝１，２，３）为三角形ΔＡ＿１Ａ＿２Ａ＿３的边长，Ｓ为ΔＡ＿１Ａ＿２Ａ＿３的面积，λ＿ｊ（ｊ＝１，２，３）为任一组正数．作者将Ｏｐｌｓｏｎｂｅｉｍ三角形不等式推广到ｎ维欧氏空间Ｅ￣ｎ中的ｎ维单形，从而获得了ｎ维单形的Ｏｐｐｅｎｂｅｉｍ不等式这里Ｖ是ｎ维单形Ａ＿１Ａ＿２…Ａ＿（ｎ＋１）的体积，Ｖ＿ｉ为顶点Ａ＿ｉ所对之侧面的面积，λ＿ｉ为任意一组正数．     

环的交换性的两点注记

讨论半素环和有单位元环的交换性，用较初等的方法证明如下两个定理，并利用这两个定理对近期的一些结果作了推广。定理１．１环Ｒ为无零因子环，ｍ和ｎ为给定自然数且ｍ＞ｎ．若有ｘ￣ｍ－ｘ￣ｎ∈Ｚ（Ｒ），则Ｒ可换。定理２．２环Ｒ有单位元，ｍ，ｎ为正整数。设（Ⅰ）设ｍ＿ｉ，ｎ＿ｉ（ｉ＝１，２…，ｋ）为非负整数，满足：且存在ｉ，ｊ使ｉ＞ｊ而ｍ＿ｉｎ＿ｊ≠０．若Ｒ为ｌ－扭自由的，且都有：则Ｒ可换。（Ⅱ）若有，其中ｍ＿１＋ｍ＿２＝ｍ，ｎ＿１＋ｎ＿２＝ｎ，ｍ＿１，ｍ＿２，ｎ＿１，ｎ＿２为自然数，且Ｒ为ｈ－扭自由的，则Ｒ可换。     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

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