Displacement wave of the blood vessel —A mechanical model

According to clinical observations and model experiment, we have developed a theoretical model and obtained its mathematical equations to investigate the displacement wave of the blood vessel. The waveform and its occurrence criterion have been obtained by using perturbation theory and numerical method. The present study suggests that the displacement wave is associated with the blood velocity waveform and the machanical behaviour of the blood vessel, but not with the pressure waveform. The clinical criterion is in agreement with the observations.     

Study on Combined Method Based on 3-D ESPI

The finite element method (FEM),whether the calculation is accurate or not,depends closely on object boundary condition.If the three dimensional displacement of the object obtained in experiment is regarded as its boundary condition,a new method combining the results of experiment and calculation,called combined method (CM),is formed.The combined method possess advantages of experiment and calculation.It can correct calculation and improve the accuracy of FEM.Accordingly it has more practicability.In this paper,the three dimensional displacement fields of a typical beam loaded at three points are tested by using 3-D electric speckle pattern interferometry (ESPI).Using the experimental results as boundary condition the whole three-dimensional displacement fields can be calculated by FEM.The beam′s three-dimensional displacement fields obtained by FEM agree very well with those obtained by experiment.This proves that the combined method is effective and practicable.     

自动显微图像处理系统的研制

为实现病理切片的自动检测研制了一套显微图像处理系统。该系统由三目照相生物显微镜、ＣＣＤ摄像机和带图像处理卡的个人计算机组成。本文介绍显微镜的自动调焦、自动搜索及状态分析判断等系统驱动功能的原理和设计，最后给出该系统临床应用的部分结果     

An unusual solvent effect in the cuprate displacement reaction of indolizidin-5-yl-methyl p-toluenesulfonate: stereoselective synthesis of indolizidine alkaloids

An unusual solvent effect in the cuprate displacement reaction of indolizidin-5-yl-methyl p-toluenesulfonate with dialkyl cuprates, derived from an alkyllithium and Grignard reagents, during the synthesis of indolizidine alkaloids 167B and 209D is described.     

留数定理在拓扑相变中的应用

留数定理是高校物理专业必修课程数学物理方法中的一个重要定理.传统教学中关于该定理的讲授着重于数学公式的推导和数学思想的传达,而对于其在具体物理问题上的应用鲜有涉及.本文以一维Su-Schrieffer-Heeger模型的拓扑相变问题为例,阐明了如何利用留数定理解析得到二阶位移量的表达式并用该物理量表征拓扑相变.在讲授留数定理的教学过程中引入具体物理问题的分析实例,可以使学生更深刻地理解数学定理中的物理内涵.     

自然弯扭梁的非线性分析

研究了两端边界均为完全约束的自然弯扭梁在小应变，大位移和大转动情况下的非线性性质，并考虑了横向剪切变形和扭转翘曲变形的影响，分析中还包括了拉伸，弯曲和扭转的各种弹性耦合。由最小势能原理可以导出所给问题的平衡方程。这里欧拉角可以用来表示任意大的转动。该方法还可方便地推广到其他各种不完全约束边界的情况。此外，利用上述结果还可以得到该梁在小位移理论中的基本方程和有关公式。     

具有自由边的复合材料层合板的解析解

从三维弹性力学基本方程出发,通过假设自由边的边界位移函数,建立了正交异性层合板的状态方程,给出了对边自由,对边简支矩形板的解析解.此解满足层合板的基本方程和层间连续条件.用本文的方法比较容易处理层合板的自由边.算例表明,数值结果具有较高的精度.     

傅里叶变换投影栅线法测量大物体的变形

本文利用傅里叶变换投影栅线技术对大物体的离面变形进行了测量，分析了大物体的尺寸给测量过程带来的主要矛盾，讨论了方法的灵敏度和精度，用计算机数值模拟技术给出了大尺寸引起的频率变化所带来的误差。结果表明，傅里叶变换投影栅线技术可以用于大尺寸物体离面变形的精确测量。     

功能梯度压电材料反平面裂纹问题

基于三维弹性理论和压电理论，导出了材料系数在横观各向同性平面内梯度分布的压电体的状态方程，进而对材料系数指数函数规律分布的半无限大压电体中的反平面裂纹问题进行了求解，利用Fourier变换给出了半无限大压电体中位移，应力，电势及电位移的解析表达式，并求得了裂纹尖端的应力强度因子和电位移强度因子，分析了不同的非均匀材料系数及几何尺寸对它们的影响。     

The displacement discontinuity method in the analysis of open cracks

The application of the displacement discontinuity numerical technique to the solution of some problems of fracture mechanics is demonstrated in the hypothesis of homogeneous and elastic material. The fracture is supposed to be free from traction and is represented by a set of constant displacement discontinuity elements, except for two parabolic elements, located at each crack tip, in order to simulate the singularity of the solution near the crack tips. On the basis of the stress and displacement field determined by the displacement discontinuity method, the stress intensity factors for mode I and II are computed according to the method of the displacements. Three examples are provided to verify the validity of the formulation.

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Sommario Lo scopo del presente lavore è di illustrare l'applicazione del metodo numerico della Displacement Discontinuity alla soluzione di alcuni problemi di meccanica della frattura, nell'ipotesi di materiale omogeneo ed elastico. La frattura è supposta aperta ed è rappresentata da una linea di elementi a discontinuità di spostamento costante, con l'eccezione di due speciali elementi parabolici, ubicati agli apici, al fine di simulare la singolarita' del campo tensionale. Sulla base del campo degli sforzi e degli spostamenti cosi determinati, vengono ricavati i fattori di concentrazione degli sforzi in modo I e II mediante il metodo degli spostamenti. Vengono inoltre riportati tre esempi di calcolo, effettuati al fine di verificare la validità del procedimento proposto.