开普勒定律的数学解释及现代证明

牛顿和开普勒关于行星运动的数学解释是科学史上极其重要的两大成就.牛顿对开普勒定律的解释,虽然包含了许多微积分的基本思想,其推理还是用的相似三角形和几何学[1].这里,我们可以给出一个现代的证明方法来解释牛顿的推算.     

随机弱大数定律和随机强大数定律的充要条件

本文讨论随机大数定律，得到随机变量序列分别服从随机弱大数定律和随机强大数定律的充要条件。     

随机环境中马氏链的大数定律和强大数定律

本文主要研究了单无限马氏环境中马氏链的几类特殊函数的大数定律及强大数定律,并且给出了加于链和过程特殊样本函数上的充分条件.     

模糊随机变量的大数定律

给出模糊随机变量的Chebyshev不等式,在此基础上证明模糊随机变量的Chebyshev大数定律,并将经典的XИHЧИH大数定律推广到模糊随机变量。     

ψ—混合序列的大数定律

本文讨论了ψ－混合序列的Ｍａｒｃｉｎｋｉｅｗｉｃｚ强，弱大数定律，其条件不同于已往文献，推广了（３）、（４）、（９）中的结果。     

Newton—Riemann时空中的动力学（Ⅱ）

讨论了Newton-Riemann时空中运动的相对性及运动方程的协变性,N－R时空中Newton力学与广义相对论的某些关系及其异同。     

非Newton流体的物质点法模拟研究

准确模拟非Newton流体的运动特性具有重要的工程意义.物质点法作为一种相对新兴的粒子型算法,其结合了Lagrange算法和Euler算法的双重优势,已广泛有效地应用于各个工程领域.基于物质点法,结合人工状态方程,分析了两种非Newton流体(cross流体和幂律流体)在平板Poiseuille流和Couette流情况下的流动特性.结果表明:对Newton流体,物质点模拟结果与理论值一致;对非Newton流体,物质点法可准确模拟其剪切稀化和剪切稠化现象.表明了物质点法在模拟非Newton流体流动问题时的适用性,拓展了物质点法的应用范围.     

喷涂于运动边界上液体薄膜射流的流变效应

采用非Newton流体的二阶流体模型分析了相对高温的液体熔体薄膜由模口喷出并涂于运动的固体膜上. 讨论了由自由面上温度梯度驱动的非Newton液体薄膜的热毛细流动, 考虑热毛细流动的流变效应. 分析是基于润滑理论近似和摄动理论近似. 得到了液体高度方程和非Newton液体薄膜的热流体力学过程描述, 具体求解了弱流变流体效应的情况.     

基于概念图的大数定律教学

介绍概念图的内涵及其基本理论,并将其应用于概率论中关于＂大数定律＂的教学过程,通过学生小组合作制作概念图,以及师生合作完善概念图,来帮助学生理清脉络、加深理解,教学实践效果良好.     

一个加强的强大数定律

本文旨在给出概率论中的一个加强的强大数定律 ,并采用“子序列方法”予以证明 .一般地说 ,子序列方法旨在将一个子序列证明 (相对地说比较容易 )的结果扩张到整个序列上去 .定理　设 { Xn,n≥ 1 }为一随机变量序列 ,令Sn =∑nj=1Xj (1 )　若诸 Xj不相关 ,且满足σ2 (Xn) =O(nθ)　　 (θ≥ 0 ) (2 )　则对任意满足α >3 2θ4(3 )　的正数 α,有Sn -E(Sn)nα → 0　 (n→∞ ) .　　　 a.e. (4)　　　证明　不失一般性 ,我们可以假设对每个 j,E(Xj) =0 ,则有E(S2n) =∑nj=1E(X2j) (5 )　注意到 (2 )式有E(S2n)≤ O(n1 θ) . (6)　…     

分配格与模格的另一二条件等价定义

针对分配格与模格的格等式定义问题,得知了二条件是定义分配格与模格的最少条件,并进一步证明了Sholander's basis是定义分配格的最短最少变量格等式,最后又从分配格和模格的基本定义出发给出了新的分配格的二条件和三条件等价定义等式及模格的二条件与三条件等价定义等式.     

A Glivenko-Cantelli Theorem and Strong Laws for L-Statistics

We prove a weighted Glivenko-Cantelli theorem and apply it to study the rate of convergence in the strong law for L-statistics.     

双曲守恒律的几种新数值方法的比较研究

本文就一维线性双曲方程的光滑和间断两种初值问题的求解,对双曲守恒律的三种新数值方法,即,WENO方法、间断Galerkin方法和全局复合方法,进行了数值比较实验,在精度、计算速度等方面的比较上,对这三个方法有了一个较详细的了解,得到了一些有用的结论。     

A Note on the Uniform Laws for Dependent Processes Via Coupling

In this note we investigate the coupling of a class of dependent sequences with an independent one having the same marginal distributions. This method is then used to prove that a uniform law of averages for this class holds if a similar law holds for the associated independent sequence.     

Existence of Multivariate Max-Universal Laws

If suitably normalized maxima of an i.i.d. sample converge in distribution, the limiting distribution is known to be max-infinitely divisible and the common distribution of the sample is said to belong to its domain of attraction. We prove the existence of max-universal distributions belonging to the domain of attraction of every max-infinitely divisible law. The proof follows in the spirit of corresponding results for normalized sums of i.i.d. random variables originated by Doeblin and shows that necessarily the sampling size has to be rapidly increasing. Restricting the growth rate of the sampling size, we prove that one necessarily deals with max-semistable distributions and their domains of attraction. 2000 Mathematics subject classification Primary—60G70 Secondary—60E99, 60F05     

Classification of Local Conservation Laws of Maxwell's Equations

A complete and explicit classification of all independent local conservation laws of Maxwell's equations in four dimensional Minkowski space is given. Besides the elementary linear conservation laws, and the well-known quadratic conservation laws associated to the conserved stress-energy and zilch tensors, there are also chiral quadratic conservation laws which are associated to a new conserved tensor. The chiral conservation laws possess odd parity under the electric–magnetic duality transformation of Maxwell's equations, in contrast to the even parity of the stress-energy and zilch conservation laws. The main result of the classification establishes that every local conservation law of Maxwell's equations is equivalent to a linear combination of the elementary conservation laws, the stress-energy and zilch conservation laws, the chiral conservation laws, and their higher order extensions obtained by replacing the electromagnetic field tensor by its repeated Lie derivatives with respect to the conformal Killing vectors on Minkowski space. The classification is based on spinorial methods and provides a direct, unified characterization of the conservation laws in terms of Killing spinors.     

A Minimality Property for Entropic Solutions to Scalar Conservation Laws in 1 + 1 Dimensions

The Second Law of Thermodynamics asserts that the physical entropy of an adiabatic system is an increasing function in time. In this paper we will study a more stringent version of this law, according to which entropy should not only increase in time, but the rate of increase is optimal in absolute value among all possible evolutions. We will establish this property in the framework of non-linear scalar hyperbolic conservation law with strictly convex fluxes.     

Group-Invariant Solutions and Conservation Laws of One-Dimensional Nonlinear Wave Equation

Based on classical Lie symmetry method, the one-dimensional nonlinear wave equation is investigated. By using four-dimensional subalgebras of the equation, the invariant groups and commutator table are constructed. Furthermore, optimal system of the equation is obtained, and the exact solutions can be gained by solving reduced equations. Finally, a complete derivation of the conservation law is given by using conservation multipliers.     

A Note on Semilocal Reciprocity Laws on Curves

The aim of this work is to offer a definition of the Contou-Carrère symbol associated with a closed point of an algebraic curve and with a local ring of dimension zero, first, and then with a semilocal ring of dimension zero, from the commutator of a certain central extension. When the curve is complete, we deduce the reciprocity law in both cases. Moreover, we give some applications to the residues, and obtain explicit relations between the classic residue and the Witt residue.

Communicated by C. Pedrini.     

Gaussian Chaos Laws on Banach Function Spaces

We give a characterization of Gaussian chaos laws on Banach function spaces which do not contain ℓ _∞ ⁿ 's uniformly. The result is applied to describe the convergence in law of U-processes with sample paths in certain Banach function spaces. __________ Published in Lietuvos Matematikos Rinkinys, Vol. 45, No. 4, pp. 553–566, October–December, 2005.