有限温度下三分裂的三种模式比较

用一个球到多个球重叠到分离的几何形状来描述裂片相互以120°方向形变(品字型),相互沿一条直线的拉长三体形变,以及先非对称后对称的级联三分裂的形变过程。方便比较只用了一个形变参数。基于液滴模型计算了表面能和库仑能,加入了新生碎片之间的核势,局域壳效应的壳能,给出三种三分裂模式的形变势能比较。考虑热核的各种温度效应,计算了在有限温度下这三种模式的位垒穿透概率,给出高温核位垒高度下降甚至位垒消失,定性给出三分裂的最可能的裂变方式。 关键词：     

冲击压缩后热传导的理论研究

 冲击压缩后的界面温度和界面附近的温度历史用Cattaneo热传导理论作了计算，并与Fourier热传导理论的结果作了比较。分析了热弛豫时间常数对界面温度的影响。     

关于抽象强阻尼波方程的指数稳定性

本文研究了Ｂａｎａｃｈ空间中的抽象强阻尼波方程ｕｔ＋ａＡｕｔ＋Ａｕ＝０的解析性与指数稳定性，其中Ａ为扇形算子，ａ＞０．该方程的指数稳定性曾被Ｍａｓｓａｔ，Ｐ．不加证明地引用．然而本文通过一个反例说明该方程不一定指数稳定，并且给出了指数稳定的充要条件．本文的结果表明，只有当阻尼系数ａ适当大时，该方程才指数稳定．     

热电效应和热电偶

 热电效应是热电温度测量的基础。该效应是德国医生塞贝克于1821年发现的,因此也称塞贝克效应。本文首先介绍塞贝克效应是如何发现的,然后在说明热电温度计的基本原理的基础上,简单介绍热电偶的基本结构、种类、用途以及今后的发展。     

具p-Laplacian算子型奇异边值问题正解的存在性

讨论了一类具pLaplacian算子型奇异边值问题(Φp (x′))′+α(t)f(x(t))=0,x(0)-βx′(0)=0,x(1)+δx′(1)=0 正解的存在性，其中Φp (x)=|x|p-2x,p>1. 通过使用不动点指数定理，在适当的条件下，建立了这类边值问题存在一个和多个正解的充分条件. 这些结果能被用来研究椭圆边值问题径向对称解的存在性.     

GLOBAL EXPONENTIAL STABILITY IN HOPFIELD AND BIDIRECTIONAL ASSOCIATIVE MEMORY NEURAL NETWORKS WITH TIME DELAYS

Without assuming the boundedness, strict monotonicity and differentiability of the activation functions, the authors utilize the Lyapunov functional method to analyze the global convergence of some delayed models. For the Hopfield neural network with time delays, a new sufficient condition ensuring the existence, uniqueness and global exponential stability of the equilibrium point is derived. This criterion concerning the signs of entries in the connection matrix imposes constraints on the feedback matrix independently of the delay parameters. From a new viewpoint, the bidirectional associative memory neural network with time delays is investigated and a new global exponential stability result is given.     

小波变换在信号奇异性检测中的应用

本文利用Marr小波变换探测信号的奇异性，得到了奇异点的位置和阶数a，以及相应的平滑因子σ和幅度k，推导出了σ满足的方程．对h(t)=l1—｜0．5-t｜^λ,λ＜2，进行了数值计算，相对误差都在1％以内．达到了比较好的效果．     

黎曼流形上不变集的分形维数估计

本文利用整体Lyapunov指数给出了光滑黎曼流形上C1-映射不变集的分形维数的上界.     

无界区域R~1上的KDV型方程的指数吸引子

本文研究了无界区域R~1上的KDV型方程,运用带权空间构造一类紧算子和算子分解的方法,得到了该方程在无界区域R~1上拥有一个指数吸引子。     

Electromagnetic Instabilities Excited by Electron Temperature Anisotropy

One-dimensional particle-in-cell simulations are performed to investigate the nonlinear evolution of electromagnetic instabilities excited by the electron temperature anisotropy in homogeneous plasmas with different parameters. The results show that the electron temperature anisotropy can excite the two right-hand electromagnetic instabilities, one has the frequency higher than Ωe, the other is the whistler instability with larger amplitude, and its frequency is below Ωe. Their dispersion relations are consistent with the prediction from the cold plasma theory. In the initial growth stage (prediction from linear theory), the frequency of the dominant mode (the mode whose amplitude is large enough) of the whistler wave almost does not change, but in the saturation stage the situation is different. In the case that the ratio of electron plasma frequency to cyclotron frequency is larger than 1, the frequency of the dominant mode of the whistler wave driRs from high to low continuously. However, for the case of the ratio smaller than 1, besides the original dominant mode of the whistler wave whose frequency is about 2.6ωe, another dominant mode whose frequency is about 1.55ωe also begins to be excited at definite time, and its amplitude increases with time until it exceeds the original dominant mode.