一类脉冲微分系统有界变差解对参数的连续依赖性

文[6]讨论了比已有结果更弱的假设条件下,固定时刻一阶脉冲微分系统与Kurzweil广义常微．分方程的关系,本文在此基础之上,建立了此类脉冲微分系统有界变差解对参数的连续依赖性定理．     

介子理论核力常数的下限

运用变分法导出由Yukawa势决定的核力常数所满足的超越不等式,由此确定核力常数大于1.     

外表设计及其案例研究（Ⅲ）

本篇给出了在外表设计方法的比较中关于八个案例［２］的一些数据结果。并对在外表设计的比较过程中所发现的一些问题进行了探讨。     

The electrical conductivity of doped oligo[aromatic diimidoselenide]

DC electrical conductivity of oligo[aromatic diimidoselenide] is studied in the temperature range 300-500 K after doping. The dopants used are I₂, FeCl₃, ZnCl₂, NaClO₄ and CuSO₄. Doping is done by mixing with 10% of the dopant, and by chemical doping. The DC electrical conductivity of the two types of doped materials is measured, compared and results interpreted. A trend of high DC electrical conductivity in the case of chemical doping especially with I₂ has been noticed. A conduction of 10⁻⁷ S cm⁻¹ is obtained at ambient or higher temperatures. This is related to a charge transfer complex formation between the oligomers and I₂. The complexation is confirmed from the electronic spectra of the chemically doped materials which showed a decrease in the π-π^* energy absorption bands and an increase in the n-π^* energy absorption bands.     

The present value of resources with large discount rates

This paper describes a method to detect limit cycles for optimal control problems in the plain. The procedure includes two steps. First, the solution paths are analytically studied for large discount rates. Second, we demonstrate by means of computer simulations how the dynamics found can be traced back to small discount rates. We apply this method to two specific examples from resource management: a taxation problem and an exploited system of predator-prey interaction which show that the limit cycles may grow as the discount rates decrease. The principle that small discount rates are more conservative than large ones is therefore questionable. The relation of our results to theorems in optimal growth theory is also discussed. This paper is part of a research project on “Cyclical Resource Management” financially supported by the German Science Foundation (DFG).     

On the stability in terms of two measures for perturbed impulsive integro-differential equations

This paper establishes several stability criteria for perturbed impulsive integro-differential equations with fixed moments of impulsive effect. By using a new comparison theorem, which connects the solutions of perturbed system and the unperturbed one, some sufficient conditions for the stability in terms of two measures are obtained for the perturbed system while unperturbed one dissatisfied which because of the effect of the perturbed terms.     

Numerical simulation of shock wave focusing over parabolic reflectors

The problem of a plane shock wave that propagates in an air media and then is reflected from a parabolic concave reflector and focuses at some region is considered. The shock focusing can greatly magnify the pressure and the temperature. The purpose of this study is to numerically simulate the shock focusing process of the reflection of shock waves from the parabolic reflectors with different depths and to analyze their associated flow fields in detail. The present solver developed is to solve the Euler equations using an improved, implicit, upwind Total Variation Diminishing scheme in a finite-volume approach. The effects of reflectors with different depths and of the incident shock Mach numbers on shock focusing are investigated. The real-gas effect is taken into account through a proper correction of the specific heat ratio of air, when high temperature occurs due to shock focusing.     

三价原子的非相对论能级结构理论

本文以原子结构的拉卡方法为基础,从三价原子的拉卡基出发,反复利用三个角动量耦合的基本关系以及3j、6j、9j符号的性质,具体推导了(n1 l1)(n2 l2)(n3l3)和(n1 l1)2(n3l3)组态下三价原子非相对论哈密顿矩阵元的计算式,除径向部分用Slater-Condon径向积分表示以外,完成了所有的角向积分与自旋求和;简要举例说明了如何利用该矩阵元计算式推导三价原子非相对论谱项能量表达式以及利用变分原理确定其中的Slater-Condon径向积分,从而求出具体的谱项能量数值.可以说,本文已建立起三价原子非相对论性能级结构的一般理论.     

Zeros of Bernoulli-type functions and best approximations

The zero sets of (D+a)ⁿg(t) with in the (t,a)-plane are investigated for and .The results are used to determine entire interpolations to functions , which give representations for the best approximation and best one-sided approximation from the class of functions of exponential type η>0 to .