二维平板可压缩边界层的二次稳定性分析

本文在二维可压缩边界层中应用Floquet分析,建立了控制次谐波稳定性的方程组,研究在二维可压缩边界层转捩过程中二维有限振幅的T-S波对三维线性小扰动的作用,并计算了来流马赫数对次谐波的产生和发展情况的影响,从中可以看出二维和三维扰动波相互作用对二维可压缩流动边界层的发展过程所产生的影响.     

EFFECT OF ADSORPTION ON THE VISCOSITY OF DILUTE POLYMER SOLUTION*

Careful measurements of the dilute solution viscosities of polyethylene glycol and polyvinylalcohol in water were carried out. The reduced viscosities of both polymer solutions plot upward curves atextremely dilute concentration levels similar to the phenomena observed for many polymer solutions in theearly 1950's. Upon observation of the changes of the flow times of pure water in and the wall surfacewettability of the viscometer after measuring solution viscosity, a view was formed that the observed viscosityabnormality at extremely dilute concentration regions is solely due to the effect of adsorption of polymerchains onto the wall surface of viscometer. A theory of adsorption effect based on the Langmuir isothermswas proposed and a mathematical analysis for data treatment was performed. The theory could adequatelydescribe the existing viscosity data. It seems necessary to correct the viscosity result of dilute polymersolutions measured by glass capillary viscometer by taking into account the effect of adsorption in all cases.     

Vibration analysis of a rod with complex boundary conditions

This paper deals with the forced longitudinal vibration of a rod carrying a concentrated mass and supported by a spring at one end. The vibration of the rod is excited by the motion of the support point at the other end. Since the boundary conditions of the problem are complex and it is necessary to consider the damping, we determine only the steady state periodic solution. First the linear system is analysed; then the material nonlinearity is considered and the approximate analytic solution of nonlinear partial differential equation with nonlinear boundary conditions is obtained by the perturbation method.     

多工作曲线-全谱交直流电弧发射光谱法测定地质样品中的铅含量

在分析仪器测定中,当元素含量变化较大时,部分低含量和高含量的样品很难得到理想的测定结果。通过使用多条工作曲线来扩大元素测定的动态范围,对地质样品中不同含量的铅进行了测定,结果表明,方法的相对标准偏差均小于10%,用多工作曲线法测得的铅含量与推荐值更接近。待测样品含量首先由第一条灵敏度高的曲线进行测定,若测定浓度大于该曲线的转换值,则由第二条灵敏度较低的工作曲线进行测定。转换值的设定要充分考虑工作曲线的衔接问题,设定的转换值浓度应该在衔接的两条工作曲线上都处于线性部分。使用多工作曲线法,设定合理的转换值,可以同时获得高、低含量样品的理想测定结果。     

光学合成孔径系统的光束控制

本文给出真空中光学合成孔径系统光束控制的物理模型。计算机数值模拟结果与理论分析吻合。另外，对孔径的活塞型和倾斜型误差的影响也进行了探讨。     

RADIATION-INDUCED DEFECTS IN RADIATION HARD AND SOFT OXIDES

The point defects of P_b and E′ in radiation hard and soft Si-SiO₂ samples were examined using electron spin resonance (ESR). The experimental results showed that these defects were correlated with the ways of oxidation process, the dosage of ⁶⁰Co radiation and the radiation bias field. Besides, the ΔH (peak of peak) of P_b and E′ indicated that P_b is the defect with slow electron spin relaxation time while E′ is the defect with fast electron spin relaxation time. Finally, the experimental results are explained qualitatively.     

用X射线衍射法研究铁基非晶材料的结构

本文用Ｘ射线衍射法针对铁基非晶材料，研究了析出晶粒的结晶度、析出α－Ｆｅ微晶尺寸、高频损耗等参数与退火温度之间的关系，得到了使铁基非晶材料高频损耗达最小值的重要结构参数范围，为机制研究和工艺控制提供了十分有用的信息．     

广播电视传播效果的模型研究

在传播学理论中,传播效果的模型研究是一个十分重要的问题.本文首次应用线性结构方程式模型研究了广播电视在亚运会宣传报导中的传播效果,将传播研究方法提高到一个新的水平. 一、引言 为了研究在亚运会前和亚运会期间广播电视的宣传效果,1990年秋由首都八个新闻单位发起并组织了全国范围的“亚运会广播电视宣传效果调查”.在数据处理的最后阶段,我们试图围绕对“亚运会的态度”、“通过新闻媒介报道的收获”(以下分别简称 “态度”和“收获”)、“广播电视接触行为”、“社会参与程度”以及“文化教育水平”等因素,构造一个能反映传播效果…