动能弹侵彻机场跑道的参数敏感性分析

为研究倾角、着速、攻角、靶体材料等因素对动能弹侵彻响应的影响,采用正交试验方法设计了数值试验和4参数3水平的正交表,进行了侵彻过程中的参数敏感性分析。经过对参数的研究,得到了影响动能弹侵彻动力学响应的主要因素。研究表明：着速和倾角对弹体减速度影响较大;影响剩余速度的主要因素是着速、倾角、基层强度;倾角和攻角对弹体的偏转影响较大。     

含裂纹弹性结构对声散射作用研究

研究了含裂纹的弹性结构对声的散射作用.应用分配形有限元和边界元相结合的方法于含裂纹的结构声相互作用问题.利用二级分形有限元方法对含裂纹结构进行离散,这将使得自由度大为减少;使用边界元方法计算外域散射声场,这将自动满足无限远辐射边界条件.数值结果初步表明:(1)随着裂纹深度的增加,结构声耦合系统的共振频率将下降;(2)裂纹附近的声场所受的影响更为明显.     

硫酸溶液中铅阳极膜研究的几个问题（三）

硫酸溶液中铅阳极膜研究的几个问题（三）①柳厚田＊王群洲周伟舫（复旦大学化学系上海２００４３３）蔡文斌（固体表面物理化学国家重点实验室厦门大学化系系厦门３６１００５）１阳极硫酸铅膜阴极还原为金属铅的液膜机理［１］奇怪的是，对铅蓄电池充电时的基本过程的机...     

1-(2-吡啶基)-2-氮杂-1,3-丁二烯的合成与应用

以2-吡啶甲醛为起始原料制备1-(2-吡啶基)-2-氮杂-1,3-丁二烯(2),然后与烯烃、炔烃发生Diels-Alder反应分别得到6-(2-吡啶基)-2-哌啶酮和6-(2-吡啶基)-二氢-2-吡啶酮.用2,3-二氯-5,6-二氰基-1,4-苯醌(DDQ)氧化6-(2-吡啶基)-二氢-2-吡啶酮得到6-(2-吡啶基)-2-吡啶酮,最后用三氯氧磷处理得到联吡啶类化合物.     

NONLINEAR DYNAMIC ANALYSIS OF FLEXIBLE MULTIBODY SYSTEM

The nonlinear dynamic equations of a multibody system composed of ?exible beams are derived by using the Lagrange multiplier method. The nonlinear Euler beam theory with inclusion of axial deformation e?ect is employed and its deformation ?eld is …     

Uranium/plutonium and uranium/neptunium separation by the Purex process using hydroxyurea

Hydroxyurea dissolved in nitric acid can strip plutonium and neptunium from tri-butyl phosphate efficiently and has little influence on the uranium distribution between the two phases. Simulating the 1B contactor of the Purex process by hydroxyurea with nitric acid solution as a stripping agent, the separation factors of uranium/plutonium and uranium/neptunium can reach values as high as 4.7·10⁴ and 260, respectively. This indicates that hydroxyurea is a promising salt free agent for uranium/plutonium and uranium/neptunium separations.     

县域耕地需求预测方法探讨

讨论了《县级土地利用总体规划编制规程》耕地需求量预测方法在应用中所存在的问题提出了改进方法，并以郑县土地利用总体规划为例双明该方法是有效的．     

Boundary element method for model analysis of 2-D composite structure

The boundary element method is used for the modal analysis of free vibration of 2-D composite structures in this paper. Since the particular solution method is used to treat the terms of body forces (inertial forces) in the equation of motion, only static fundamental solutions are needed in solving the problem. For an isotropic cantilever beam, the numerical results obtained by using the BEM presented in this paper are in good agreement, with, those of using FEM or other BEM, but this BEM can also be used to analyze problems for anisotropic materials. For simply supported composite laminated beams, the comparisons of the numerical reslts obtained by this method with the analytical results obtained by 1-D laminated beam theory indicate that if the ratio of length/thickness is greater than 20, the results of the two methods are in good agreement, but if the ratio of length/thickness is less than 20, big errors will occur for 1-D laminated beam theory.     

各向异性体对瞬态SH波散射问题的边界元方法

本文利用Fourier变换和加权残数法建立了正交各向异性体反平面瞬态波散射问题的边界积分方程,构造了在边界上能满足波动方程的边界元函数,它比常用的二次元和高次元具有较好的适应性。数值结果表明利用该形函数计算高频情形下的散射问题具有很高的精度。     

物理实验中的不确定度及其在声速测量过程的应用

本文对物理实验中的不确定度进行了比较系统的介绍,并将其应用到声速测量这个典型的物理实验当中,显示出不确定度在物理实验的数据处理中的重要性。