C60与硅烯环加成反应机理的理论研究

用半经验AM1法研究了C     

Beam dynamics simulations of the injector for a compact THz source

Terahertz radiation has broad application prospects due to its ability to penetrate deep into many organic materials without the damage caused by ionizing radiations. A free electron laser （FEL）-based THz source is the best choice to produce high-power radiation. In this paper, a 14 MeV injector is introduced for generating high-quality beam for FEL, is composed of an EC-ITC RF gun, compensating coils and a travelling-wave structure. Beam dynamics simulations have been done with ASTRA code to verify the design and to optimize parameters. Simulations of the operating mode at 6 MeV have also been executed.     

自旋极化电子碰撞谱仪的研制进展

与电子自旋相关的效应在散射过程中起着十分重要的作用，但却常常被较强的库仑相互作用所淹没，使得以自然电子为探针的散射实验很难对其进行直接观测。以极化电子作为探针，研制极化电子碰撞谱仪，将为开展自旋相关效应的实验研究奠定基础。本简述了极化电子与原子分子碰撞研究的意义，并介绍了清华大学物理系极化物理实验室自行开发的GaAs极化电子源及基于该极化电子源的碰撞谱仪的研制情况。     

CONSTRUCTING UNIFORM DESIGNS WITH TWO- OR THREE-LEVEL

When the number of runs is large, to search for uniform designs in the sense of low-discrepancy is an NP hard problem. The number of runs of most of the available uniform designs is small (≤50). In this article, the authors employ a kind of the so-called Hamming distance method to construct uniform designs with two- or three-level such that some resulting uniform designs have a large number of runs. Several infinite classes for the existence of uniform designs with the same Hamming distances between any distinct rows are also obtained simultaneously. Two measures of uniformity, the centered L2-discrepancy (CD, for short) and wrap-around L2-discrepancy (WD, for short), are employed.     

全平面上零级Dirichlet级数的增长性

在较一般的指数条件下,研究了全平面上零级Dirichlet级数的增长性,得到了一些新的结果.     

能量耗散技术探索液态物质结构的新进展

本文介绍了近期用能量耗散方法探索液态物质结构及其动力学行为的新进展。其中液态物质包括了金属及其合金的熔融态，以及高分子聚合物的溶液和熔融态。该方向的研究工作虽才开始，但已显示出能量耗散技术的广阔应用前景。     

极限疑难

在■的定义中不可缺少的任意小正数■必须具有(0,1/n)的性质,但(0,1/n)=φ(空集)。在(x)=+∞的定义中不可缺少的任意大正数G必须具有(n,+∞)的性质。而(n,+∞)=φ。因而在极限定义中不可缺少的任意小正数(?)或任意大正数G具有矛盾的性质,一方面是(0,+∞)中的元素,另一方面又是空集的元素,即不是(0,+∞)中的元素,构成极限疑难。     

齐权方程及其解法

一般教科书中都讲了一类可化为变量可分离的微分方程即齐次方程.如果将齐次函数概念推广,就得到另一类可化为变量可分离的方程即本文将要介绍的齐权方程.