以Euler梁为波导耦合的超声发射换能器与接收换能器输入—输出理论分析

应力波因子技术是近几年发展起来的评估复合材料损伤的新技术，本文讨论了该技术应用于梁类构件时超声发射换能器与超声接收换能器输入－输出的理论分析问题。通过引入简化假设首先建立起问题的方程，然后借助于多重积分变换方法获得了发射换能器与接收换能器输入－输出关系的频域显式表达式。以此为基础进一步应用解析方法和快速傅里叶变换（ＦＦＴ）数值方法对接收换能器的时域输出特征进行了理论分析和数值计算。根据本文的分析与计算，最后得出了一些有益的结论     

Photon scanning tunneling microscope,now and in the future

The concept of photon tunneling and the principle of the photon scanning tunneling microscope (PSTM) are described. The history of the PSTM and its development in China are reviewed. The principal problem in the recent development of the PSTM, together with its solution, is discussed. The distinguishing features and the future of the PSTM are described.     

PVTt法气体流量标准装置中标定时间的确定

PVTt法气体流量标准装置是测量气体质量流量的一种高精度标准装置,通过测量装置中标准容器内充气前后的气体压力、温度来确定流过被检表的气体实际质量流量值.该气动系统中的充气过程是热力变化和传热变化的复杂过程.该文运用热力学、气体动力学中喷管及激波理论,研究了标定时间理论值的计算,并进行了实例分析.研究表明启动段时间对测量精度影响甚微,而充气过程中的多变指数n及控制元件(喷管)的选用对测量精度影响较大.     

High-resolution wide-field surface plasmon microscopy

This paper describes the application of a Köhler illuminated high‐resolution wide‐field microscope using surface plasmons to provide the image contrast. The response of the microscope to a grating structure in both the Fourier and the image planes is presented to demonstrate image formation by surface waves. The effect of spatial filtering in the back focal (Fourier) plane to enhance image constrast is described. We also discuss how the surface wave contrast mechanism affects the imaging performance of the microscope and discuss factors that can be expected to lead to even greater improvements in lateral resolution and sensitivity.     

KSpaceNavigator as a tool for computer-assisted sample tilting in high-resolution imaging, tomography and defect analysis

This article describes a novel software tool, the KSpaceNavigator, which combines sample stage and crystallographic coordinates in a control sphere. It also provides simulated kinematic diffraction spot patterns, Kikuchi line patterns and a unit cell view in real time, thus allowing intuitive and transparent navigation in reciprocal space. By the overlay of experimental data with the simulations and some interactive alignment algorithms, zone axis orientations of the sample can be accessed quickly and with great ease. The software can be configured to work with any double-tilt or tilt–rotation stage and overcomes nonlinearities in existing goniometers by lookup tables. A subroutine for matching the polyhedral shape of a nanoparticle assists with 3D analysis and modeling. The new possibilities are demonstrated with the case of a faceted BaTiO₃ nanoparticle, which is tilted into three low-index zone axes using the piezo-controlled TEAM stage, and with a multiply twinned tetrahedral Ge precipitate in Al, which is tilted into four equivalent zone axes using a conventional double-tilt stage. Applications to other experimental scenarios are also outlined.     

SLAM无损检测技术的研究

本文分析了声波对有损耗样品板的透射规律，得到了透射率|W|^2的公式。对于两类样品板，通过数值计算得到了它们的响应曲线|W|^2θ，通过调节入射角θ1得到|W|^2的最大值。所做工作有利于提高SLAM的检测灵敏度。     

镀铬对光刻胶全息光栅掩模槽形的影响

为了研究镀铬对光刻胶光栅掩模槽形的影响,分析了铬膜反射引起的沿垂直光刻胶表面的驻波效应。分析表明驻波效应的对比度为0.28,不能忽略。将镀铬基底与普通的玻璃基底的掩模槽形对比,发现明显的不同。槽形模拟表明这种不同是由于驻波效应引起的。驻波效应会使掩模形成阶梯结构,且阶梯高度差正好为驻波波节间距离。     

UG应用技法

通过使用UG规律曲线和自由曲面建立的命令，一步一步掌握UG高级建模方法。     

基于双压驱动的恒流斩波系统的设计

恒流斩波电路中，步进电机的驱动电压高，绕组回路阻抗低，电流上升较快。单一的恒流驱动电路在低频时绕组电流上升过快，容易导致低频过冲振荡现象。为避免振荡，本文采用双压驱动与恒流斩波驱动相结合：低速运行时采用低电压供电，低频过冲振荡小，转动平稳；高速运行时采用高电压供电，高频输出扭矩大，不易堵转。     

THEORETICAL ANALYSIS AND EXPERIMENTAL VERIFICATION ON TERNARY-WAVES METHOD TO COMPILE ACCELERATED SPECTRA

The equivalent damage calculation formulae of fatigue crack formation and growth are established. In order tocompile the fatigue crack formation and growth accelerated load spectra, the main wave shapes and load sequence of theactual load spectrum are kept constant, and the carrier waves are cut off. And secondary waves are put together into newsecondary waves to shorten the test time according to the equivalent damage calculation formulae respectively. Then bythe fatigue cumulative damage calculation of the fatigue crack formation and growth accelerated load spectra, the onecorresponding to the bigger damage is determined as the fatigue accelerated test load spectrum. Therefore in the test process, the fatigue accelerated test spectrum may be applied till fatigue failure, the engineering fatigue crack length of full-scale structure need not be inspected, and the fatigue crack formation accelerated load spectrum need not be transferredinto the fatigue crack growth accelerated load spectrum. Finally, it