压电复合材料中正n边形孔边裂纹的反平面问题研究

本文基于Cauchy积分理论和Schwarz-Christoffel(SC)变换技术,针对压电复合材料中带一条裂纹的正n边形孔口缺陷的反平面断裂力学进行了探究.假设满足电不可通边界条件,利用Cauchy积分公式和留数定理,获得了任意正n边形裂尖处应力和电位移两个场强度因子以及全能量释放率的封闭形式的显式解.当正n边形边...     

Light transmission in porous silicon dioxide filled with liquids of different refractive indices

Optical transmission at 532 nm from nonabsorbing disordered porous silicon dioxide has been studied experimentally. The transmission behaviors can be adjusted by filling the pores with liquids of different refractive indics, which are analyzed based on the theory of diffusion in a weak scattering regime. In our experiment, the transmission coefficient changes from a value less than 1% to one that is greater than 75%, that is, the opaque sample becomes transparent, which means that the transport mean free path of light within the material has been effectively adjusted. In addition, this method is a useful nondestructive method to derive the refractive index of an unknown bulk porous material.     

用整体思想求解数学问题的若干形式

整体思想是一种重要的解题思想,是思维深刻性的体现,根据问题的不同特点,可以展现出多种思考模式.本文介绍整体思想求解数学问题的若干形式.     

美国物理教育研究动向

物理教育研究(PER)在美国已经发展成物理学研究的一个新分支,正在对物理教学改革产生实质性的影响.其研究领域中新的课程、教学方法及资源的设计与开发对我国的物理教育研究及课程和教学改革具有重要的借鉴意义.     

双量子阱中光子辅助电子自旋隧穿

采用单电子有效质量近似理论, Floquet理论和传递矩阵方法, 对包含时间周期场的双量子阱中单电子的自旋隧穿特性进行了研究, 对InP/InAs半导体材料进行了数值计算. 重点研究了Rashba型和Dresselhaus型自旋轨道耦合、量子阱结构以及偏压对电子隧穿的影响. 这些结果可以为设计和调控半导体自旋电子器件提供一定的理论依据. 关键词： 光子辅助隧穿 隧穿概率 量子阱     

模态分析和有限元法结合识别机械结构结合面动力学参数的研究

本文探讨了一种将实验模态分析和有限元法相结合，识别机械结构结合面动力学参数的新方法，以解决大型复杂机装拆不例，难于用实验方法识别部件间结合面动力学参数的问题。用些方法识别了一台遥臂钻床的接触度和接触阻尼。     

THE STUDY ON A KIND OF CONTROL SYSTEM WITH NONLINEAR PARABOLIC DISTRIBUTED PARAMETERS

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅａｃｔｉｖｉｔｉｅｓｓｕｃｈａｓｔｈｅａｅｒｏｓｐａｃｅｅｎｇｉｎｅｅｒｉｎｇｈｅａｔｐｒｏｔｅｃｔｉｏｎ[1,2 ],ｔｈｅｌａｒｇｅ＿ｓｃａｌｅｃｏｎｃｒｅｔｅｐｏｕｒｉｎｇ ,ｔｈｅｃｈｅｍｉｃａｌｐｒｏｄｕｃｔｉｏｎ ,ｔｈｅｐｏｗｄｅｒｍｅｔａｌｌｕｒｇｙａｎｄｔｈｅｆｉｒｅｓａｆｅｔｙｅｎｇｉｎｅｅｒｉｎｇ[3,4],ｔｈｅｒｅｉｓｏｎｅｋｉｎｄｏｆｎｏｎｌｉｎｅａｒｐａｒａｂｏｌｉｃｄｉｓｔｒｉｂｕｔｅｄｐａｒａｍｅｔｅｒｃｏｎｔｒｏｌｓｙｓｔｅｍｗｉｔｈｍｏｖｉ…     

Numerical study of shock diffraction in dusty gases

ＮＵＭＥＲＩＣＡＬＳＴＵＤＹＯＦＳＨＯＣＫＤＩＦＦＲＡＣＴＩＯＮＩＮＤＵＳＴＹＧＡＳＥＳＷｕＱｉｎｇ－ｓｏｎ（吴清松）ＺｈｕＨｏｎｇ（朱红）ＸｕＹａｎ－ｈｏｕ（徐燕侯）（ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙｏｆＣｈｉｎａ,...     

Control of transpiration cooling system and its characteristics

This paper gives the mathematical model of three-dimensional transpiration cooling control system in heat shield.Generally,it.a non-linear control system on variable-domain mixed up with both distributed and concentrated parameters.This paper points out that the thermal and ablative problems of the shield can be solved solely with the coolant flow only under one-dimensional incompressible or steady condition.In regard to the surface ablating problem of the thermal shield,the control schemes of the system,including its simplified condition and the characteristics of one-dimensional point control is suggested here.Solutions of the equilibrium state are given with or without phase change as far as the coolant is concerned.     

金刚石膜微结构的慢正电子束测量研究

The microstructure of diamond films was studied by slow positron beam and Raman spectroscopy. For the Raman spectroscopy experiment on diamond films, a high fraction of the sp3 hybridized bond was detected in samples. Positron annihilation spectra analysis further illuminated that the concentration and types of defects were different in each sample. S-E curves of all samples showed that diamond crystal structures had obvious variation in each sample. These results indicated that positron annihilation spectroscopy was an effective means to measure microstructure of diamond films.