特殊非负矩阵对的指数

文章主要考虑了特殊非负矩阵对的本原指数，其中与该负矩阵对相应的图包含两个圈．我们给出了该本原指数的界并且对其对应双色图的极图进行了刻画．     

虚拟世界与艺术呈现的困境

虚拟世界是由人工智能、计算机图形学、人机接口技术、传感器技术和高度并行的实时计算技术等集成起来所生成的模拟世界。在当代社会,虚拟世界形成一个人类交流信息、知识、思想和情感的新型模式已深刻地影响并主导了人类生活。在这一境遇中,传统艺术观念受到前所未有的挑战,尤其是艺术精神的引申意义受到质疑和艺术的“乌托邦”色彩被淡化,导致艺术呈现走入困境。     

红色旅游发展模式探讨

美国、法国、德国等发达国家将历史传统教育置于亲身参与背景下,收到了很好的效果,积累了丰富的经验,提供了很好的借鉴。以革命纪念地、纪念物为载体的“红色旅游”是爱国主义教育、历史教育的重要组成部分,注重参与、体验的构建,“寓教于乐”,很可能是目前红色旅游的一个具有很大潜力的发展模式。     

语言实验室安装前的准备及竣工后的验收

安装前的准备工作和竣工后的验收工作是影响语言实验室正常运行的两个重要因素．文章针对上述两点进行阐述．     

计算学科中的实验体系

本文讨论了计算学科中的实验体系,阐述了建立实验体系的框架,进入实验规划和实施方案和内容,讨论了实验改革和创新的思路,以及建立软件实验、虚拟实验的探索和建立移动实验室的构想。     

Ruin Probability with Variable Premium Rate and Disturbed by Diffusion in a Markovian Environment

We consider a risk model with a premium rate which varies with the level of free reserves. In this model, the occurrence of claims is described by a Cox process with Markov intensity process, and the influence of stochastic factors is considered by adding a diffusion process. The integro-differential equation for the ruin probability is derived by a infinitesimal method.     

Newton's Easy Quadratures ``Omitted for the Sake of Brevity'

In the 1687 Principia, Newton gave a solution to the direct problem (given the orbit and center of force, find the central force) for a conic-section with a focal center of force (answer: a reciprocal square force) and for a spiral orbit with a polar center of force (answer: a reciprocal cube force). He did not, however, give solutions for the two corresponding inverse problems (given the force and center of force, find the orbit). He gave a cryptic solution to the inverse problem of a reciprocal cube force, but offered no solution for the reciprocal square force. Some take this omission as an indication that Newton could not solve the reciprocal square, for, they ask, why else would he not select this important problem? Others claim that ``it is child's play' for him, as evidenced by his 1671 catalogue of quadratures (tables of integrals). The answer to that question is obscured for all who attempt to work through Newton's published solution of the reciprocal cube force because it is done in the synthetic geometric style of the 1687 Principia rather than in the analytic algebraic style that Newton employed until 1671. In response to a request from David Gregory in 1694, however, Newton produced an analytic version of the body of the proof, but one which still had a geometric conclusion. Newton's charge is to find both ``the orbit' and ``the time in orbit.' In the determination of the dependence of the time on orbital position, t(r), Newton evaluated an integral of the form ∫dx/x <sup>n</sup> to calculate a finite algebraic equation for the area swept out as a function of the radius, but he did not write out the analytic expression for time t = t(r), even though he knew that the time t is proportional to that area. In the determination of the orbit, θ (r), Newton obtained an integral of the form ∫dx/√(1−x<sup>2</sup>) for the area that is proportional to the angle θ, an integral he had shown in his 1669 On Analysis by Infinite Equations to be equal to the arcsin(x). Since the solution must therefore contain a transcendental function, he knew that a finite algebraic solution for θ=θ(r) did not exist for ``the orbit' as it had for ``the time in orbit.' In contrast to these two solutions for the inverse cube force, however, it is not possible in the inverse square solution to generate a finite algebraic expression for either ``the orbit' or ``the time in orbit.' In fact, in Lemma 28, Newton offers a demonstration that the area of an ellipse cannot be given by a finite equation. I claim that the limitation of Lemma 28 forces Newton to reject the inverse square force as an example and to choose instead the reciprocal cube force as his example in Proposition 41. (Received August 14, 2002) Published online March 26, 2003 Communicated by G. Smith     

磁放大器原理及执行器故障分析

论述了磁放大器的工作原理和特点 ,介绍了磁放大器在执行器中的应用 ,对执行器的两种常见故障作了分析     

组合数学的游戏起源

数学家对游戏问题的思考与解答，促进了数学的产生与发展，组合数学许多研究方向的产生，就直接来源于一些经典的数学游戏，同时游戏也丰富了组合数学的研究方法与内容。     

杨氏模量测量的一个程序设计

本文通过用计算机对杨氏模量测量的程序设计，说明微机不仅可以迅速完成数据处理工作，还可以判断实验结果，从而更好地探索实验规律。