硼中子俘获治疗实验装置射频功率源系统

中国科学院高能物理研究所建造了一台基于加速器的硼中子俘获治疗（BNCT）实验装置。射频功率源系统为352.2 MHz射频四极加速器（RFQ）提供高频功率,使束流离开RFQ时,其能量达到3.5 MeV。BNCT射频功率源系统主要包括速调管功率源、数字低电平控制系统、射频传输系统。本文介绍了BNCT射频功率源系统,主要包括物理需求、系统组成、关键设备、安装和调试。目前该装置已进行动物实验,加速器打靶束流功率4.3 kW,加速器射频功率源系统运行稳定。     

小阻尼转子系统动力学的本征解

本文把小阻尼转子系统的动力学方程化为一种新形式，用摄动法展开该方程，导致一个反对称矩阵的广义本征值问题，因此获得了高精度的本征解。文中给出了一个简例。     

混凝土核安全壳干缩应力的计算

提出内约束干缩应力和外约束干缩应力的概念,利用混凝土的蠕变理论,建立了考虑施工过程的有限元计算模型,编制了电算程序,计算了秦山核安全壳在施工过程中的干缩应力。     

HAMILTONIAN SYSTEM AND SIMPLETIC GEOMETRY IN MECHANICS OF COMPOSITE MATERIALS (Ⅰ)——FUNDAMENTAL THEORY

For the first time, Hamiltonian system used in dynamics is introduced to formulate statics and Hamdtonian equation is derived corresponding to the original governing equation, which enables separation of variables to work and eigen function to be obtained for the boundary problem. Consequently, analytical and semi-analytical solutions can be got. The method is especially suitable to solve rectangular plane problem and spatial prism in elastic mechanics. The paper presents a new idea to solve partially differential equation in solid mechanics. The flexural problem and phane stress problem of laminated plate are studied in detail.     

一类基于Hamilton体系的半解析法

利用偏微分方程在Hamilton体系中的表示和二类变量变分原理,结合有限元法,提出一类基于Hamilton体系的半解析法。本文以二阶非齐次椭圆型方程为例,给出了这类半解析法中的一种的有限元列式和算例,与解析解、Ritz法、有限条法和有限元法的结果比较表明,此法具有较高的精度,还可求解其它其些偏微分方程,有一定的普遍意义。     

一维热传导方程有限元解的计算准则

用有限元法求解热传导方程经常会得到振荡或超界的结果,这个重要问题一直没得到很好的解决。我们提出时间单调性和空间单调性的概念,推导和证明了获得合理解答的计算准则。对一维问题,推出关于△t/△x~2的上下界公式,并详细讨论了时间单调性,空间单调性及其与△t/△x~2的关系。最后把本文的计算准则与传统的特征值法作了比较。     

RFQ加速器中二极模稳定杆作用机理的研究

RFQ加速器中的二极模场给束流施加一个偏转力,导致束流损失在机器上.因此,必须采取降低二极模场的措施.人们提出采用二极模稳定杆使二极模频率远离四极工作模.在一台RFQ冷模上开展的实验研究中,发现了一些与二极模稳定杆作用机理相关的新现象,本文报告这些实验结果,并对其进行分析解释.根据这些结果,提出,利用非对称性地插入二极模稳定杆,可以降低非对称RFQ腔体中的二极模场分量.     

CSNS H^- ion source test stand

The Penning surface plasma source is adopted as the China Spallation Neutron Source (CSNS) H^- ion source. The designed energy and beam current of the source are 50 keV and 20 mA, respectively, with a normalized root mean square (norm. rms.) emittance of 0.2 πmm·mrad. The construction of a H^- ion source test stand has been completed, and the commissioning of the source is in progress. Stable H^- ion beams with energy of 50 keV and current up to 50 mA are attained. Emittance measurement for the H^- beam is being prepared.     

HAMILTONIAN SYSTEM AND SIMPLETIC GEOMETRY IN MECHANICS OF COMPOSITE MATERIALS (Ⅱ)——PLANE STRESS PROBLEM

Fundamental theory presented in Part (Ⅰ) is used to analyze anisotropic plane stress problems. First we construct the generalized variational principle to enter Hamiltonian system and get Hamiltonian differential operator matrix, then we solve eigen problem; finally, we present the process of obtaining analytical solutions and semi-analytical solutions for anisotropic plane stress porblems on rectangular area.