交流示波极谱法中if～E曲线的研究(Ⅰ)——求取if～E曲线的仪器装置

本文报道求取i_f～E曲线的一种双电解池差分装置。通过扣除交流示波极谱法总电流中双电层充电电流i_c,测量法拉第电流对工作电极电位的曲线(即i_t～E曲线),可提高灵敏度。     

非线性介质表面任意阶谐波的反射和透射

本文详细分析了线性介质与非线性介质界面任意阶谐波的反射和折射定律;导出了反射波和透射波的精确表达式;对泵浦波正入射(垂直于界面入射)时,满足相位匹配的场进行了深入的讨论。     

Weakly Nonlinear Oscillatory Waves with Multi-phases in Ideal Incompressible Fluid

In this paper, we apply the technique of weakly nonlinear geometric optics to study weakly nonlinear oscillatory waves with multi-phases in d-dimensional ideal incompressible fluid for d ≥ 2. Precisely, we give a rigorous asymptotic expansion for the solution of the oscillatory initial value problem to the ideal incompressible Euler equations. Generally, this problem is not well posed. However, the coherence assumption and small divisor property imposed on the phases functions lead to a compatibility condition for the solvability of profile equations from which we can determine every profile.     

Elastoplastic analysis of cylindrically orthotropic composite lamina with a circular hole under uniform pressure

This paper presents the standard parametric representation of the Tsai-Hill yieldcriterion in a state of plane stress and the equations governing the stress distribution in acylindrically orthotropic composite lamina with a circular hole under uniform pressure forthe three cases: (a) elastic state.(b) limit state and (c) elastoplastic state. The formulasfor the yield pressure and the limit pressure have been obtained.     

海洋内波研究现状简介

Ⅰ.引言内波是发生在稳定层化流体中的一种波动,其最大振幅在流体内部,频率介于惯性频率f与浮性频率N之间。在海洋中由于海水的层化,内波是很普遍的现象。它具有很强的随机性,时空尺度分布在相当宽的范围内,典型地有:振幅为几米至几十米乃至百米;水平波长为百米至几十公里;铅垂波长为几十米至几公里;周期为几分钟至几十小时。因而海洋内波是很容易观测到的。      

Numerical simulations of the nonlinear propagation of femtosecond optical pulses in gases

A two-dimensional axisymmetric model of the propagation of intense femtosecond laser pulses through dispersion-free transparent media is described. The effects of diffraction, nonlinear Kerr effect (instantaneous and retarded) and multiphoton ionisation are included. Numerical results concerning air and other gases are discussed. In particular, time self-compression of femtosecond pulses is predicted. Stable self-guided pulses are simulated, in agreement with recent experimental observations. Received: 19 June 1998 / Received in final form: 14 January 1999     

平面波在任意磁化方向旋磁媒质中传播时的极化特性

在铁氧体基片平面电路和发射天线中必须研究平面波在任意磁化方向旋磁媒质中的传播。这时平面波的特征波为ＴＥ波,其磁通密度、磁场、电通密度、电场的极化是不相同的,磁场的极化方向为左、右椭圆极化。     

Yamabe不变量与在非紧流形上预定纯量曲率

我们得到关于Ｙａｍａｂｅ不变量的某些条件,使得非紧流形通过共形形变后,纯量曲率为常数．     

变质量完整力学系统的Lie对称与守恒量

研究变质量完整系统的Lie对称和守恒量。利用常微分方程在无限小变换下的不变性建立系统Lie对称的确定方程。给出结构方程和守恒量。举例说明结果的应用。     

一个二流体系统中非线性水波的Hamilton描述

讨论了一个二流体系统中非线性水波的Hamilton描述,该系统由水平固壁之上的两层常密度不可压无粘流体组成,上表面为自由面.文中将速度势函数展开成垂向坐标的幂级数,在浅水长波的假定下,取下层流体的“动厚度”与上层流体的“折合动厚度”为广义位移、界面上和自由面上的速度势为广义动量,根据Hamilton原理并运用Legendre变换导出该系统的Hamilton正则方程,从而将单层流体情形的结果推广到分层流体的情形.