使用.net实现P2P应用

Peer-to-Peer(P2P)网络被喻为第三代网络,采用的是点对点分散式网络架,它不需要服务器的中转,使 用户与用户之间的连接更加方便、直接．net是微软公司近年来推出的新的软件开发平台,能简单、方便地构 造P2P应用．本文介绍了如何使用．net实现P2P应用的方法．     

从一个案例看电子数据库的版权保护*

电子数据库的版权保护的问题是目前计算机技术版权保护中的一个热点，本文通过一个软件版权纠纷的案例，讨论了其中存在的问题，即在现阶段，末有专门保护数据库法律的情况下，可否把电子数据库与程序一起纳入软件程序的范围的问题，并提出实施方法建议。     

三棒串接Nd∶YAG激光谐振腔的稳定性研究

采用激光谐振腔的矩阵理论分析了三棒串接的Nd∶YAG激光器的稳定特性 ,给出了对称放置的平行平面腔稳定区范围 .结果表明 ,合理选择棒的位置及工作参数 ,可提高激光器的输出功率 .另外 ,三根棒的热效应不相同会缩小激光器的稳定区范围 .设计了三棒串接的激光器 ,获得了 970W的输出功率 .     

突发性泥沙灾害危险性快速区划方法

突发性泥沙灾害危险性区划是防灾减灾工作的重要依据．针对传统区划方法存在周期长、成本高、地域性强、对数据完备性要求高等问题，本文基于快速评估思想提出了突发性泥沙灾害危险性的快速区划方法．该方法在确定区划原则、形式、单元、指标的基础上，通过参照系建立、参照组匹配、邻域估测及邻域合并等步骤进行区域泥沙灾害危险度的判定和区划．本文提出的方法具有快速、高效、实用的特点，且在一定程度上能够弥补因资料不足而带来的区划困难，能够更好地服务于防灾减灾工作．     

INTERPOLATED FINITE ELEMENT METHODS FOR SECOND ORDER HYPERBOLIC EQUATIONS AND THEIR GLOBAL SUPERCONVERGENCE

We develop the interpolated finite element method to solve second-order hy-perbolic equations. The standard linear finite element solution is used to generate a newsolution by quadratic interpolation over adjacent elements. We prove that this interpo-lated finite element solution has superconvergence. This method can easily be applied togenerating more accurate gradient either locally or globally, depending on the applications.This method is also completely vectorizable and parallelizable to take the advantages ofmodern computer structures. Several numerical examples are presented to confirm ourtheoretical analysis.     

RELIABILITY BOUNDS IN NWUE CLASS WITH KNOWN MEAN AND VARIANCE

Let. F∈NWUE with known mean and variance. In this note a simple sharplower bound of F=1-F(t) is given.     

NEUMANN SERIES SOLUTION TO A NEUTRON TRANSPORT EQUATION OF SLAB GEOMETRY

This paper deals with the solution to an energy, dependent stationary neutrontransport equation of slab geometry. In L~p space, the equation is converted into an equiva-lent integral equation. By the study of the corresponding integral operator and its spectralradius, results of Neumann series solution are obtained, and an easy-verified condition thatthe transport equation has a nonnegative solution is given.     

A FURTHER GENERALIZATION OF JUNG''''S THEOREM

Let G be a graph of order n. We define the distance between two vertices u andv in G, denoted by d(u, v), as the minimum value of the lengths of all u-v paths. We writeσ_k(G)=min{∑_i=1~k d(v_i)|{v_1, v_2,…, v_k} is an independent set in G} and NC2(G)=min {|N(u)∪N(v)| | d(u, v)=2}. We denote by ω(G) the number of components of agraph G. A graph G is called 1-tough if ω(G\S)≤|S| for every subset S of V(G) withω(G\S)>l. By c(G) we denote the length of the longest cycle in G; in particular, G iscalled a Hamiltonian graph if c(G)=n. H.A. Jung proved that every 1-tough graphwith order n≥11 and σ2≥n-4 is Hamiltonian. We generalize it further as follows: ifG is a 1-tough graph and σ3(G)≥n, then c(G)≥min {n,2NC2(G)+4}. Thus, theconjecture of D. Bauer, G. Fan and H.J. Veldman in [2] is completely solved.     

线性代数教学内容改革的研究与实践

针对当前线性代数教材在教学内容及内容编排上存在的问题,提出了改进方案,并在教学过程中进行了实践。     

基质组成对MgO-Al2O3质浇注料性能的影响

研究基质组成对MgO-Al2O3质浇注料热震稳定性和抗渣性能的影响.结果表明,随着α-Al2O3含量的增加,MgO-Al2O3质浇注料1600℃×3 h抗折强度逐渐降低,α-Al2O3质量分数大于15%后抗折强度明显增大;α-Al2O3加入量为10%～15%时浇注料具有最佳的热震稳定性;随着α-Al2O3含量的增加,浇注料渗透指数明显减小,侵蚀指数逐渐增大.MgO-Al2O3质浇注料的性能主要与基质的组成和显微结构相关.