用参考物体全息法测量位移矢量方向

本文提出了一种测量物体位移矢量方向的方法一参考物体全息法，该方法将一个参考物体置于被测物体的一侧，然后在一张干版上记录两个双曝光全息图：一个是受到干版位移调制的被测物体和参考物体的双曝光全息图，一个是被测物体的非调制干涉图。前者用于测量位移矢量的方向，后者用于测量被测体位移的数值场。文中主要介绍了参考物体全息法测量位移矢量方向的原理。文后给出了实验结果。     

偏振多通道相机研测二维热形变场

研制了偏振多通道相机，并采用该相机进行激光散斑照相，对高温动态热形变场进行了研测，拍摄一张散斑图可得到物体在热形变过程中各瞬志热形变场的二维信息。通过滤波技术可再现各瞬时热形变场的分布情况及其变化情况。     

电子错位散斑条纹特性的实验研究

通过位移位相存在的真实性实验和位移梯度的解相关实验，证实电子错位散斑干涉术的条纹是由物体变形所引起的位移位相和位移导数位相及由位移和位移导数共同决定的附加位相之和的余弦条纹。这种余弦条纹的质量和对比度与位移、位移导数及滤波光孔的直径有关。     

论激光散斑干涉法分离面内位移和法向位移

在面内位移的研究中，物体表面的散斑图由透镜的象平面上的底片进行记录，通过变形前后的两次曝光，得到散斑干涉图。散斑干涉图通过富里叶滤波产生一组等值线，其大小和方向表征了物体平面内位移的大小和方向，但是这里忽略了物体的法向位移在象平面上所引起的变化量。     

数字全息干涉位移场分离研究

提出了一种基于窗口傅里叶脊的离面与面内位移分 离方法,应用于数字全息的多分量干涉相位场 分离。首先,物光束对称照射待测物体, 参考光束直接照射CCD靶面,由CCD相机记录物体变形前后的两幅离轴数字全息图;然后,采 用菲涅尔衍射积分法再现物体变形前后的复物光场,再由两幅复物光场共轭相 乘构建干涉场,利用幅度区分准则和窗口傅里叶变换处理复干涉场,通过窗口傅里叶脊值的 搜索,提取不 同灵敏度矢量物光对应的干涉相位分量;再对干涉相位场进行简单数值运算,将面内与离面 位移场分离出 来。最后,对周边固定、点加载、绕轴向旋转的Al制圆盘三维位移场进行实际测量。实验结 果验证了本文方法的有效性。     

视觉注意机制的运动方向异常检测方法

针对传统运动方向异常检测方法需要人工参与、智能化较低等缺点,提出了一种新的基于视觉注意机制的运动方向异常检测方法。该方法通过合成源图像的空间导数图与时间导数图获得运动边缘,求取沿空间各方位分布的运动方向特征图。在此基础上,利用所提出的基于运动区域面积的归一化方法对得到的每一幅特征图按照显著性高低分别赋予不同的权重,完成不同运动方向特征的相互竞争。最后融合经过归一化处理的特征图以得到最终的运动显著图。该显著图中运动方向具有显著性的物体得到有效突出,达到了存在多个运动物体的情况时,运动方向上具有显著性的物体能够更加有效、智能地检测出来的目的。     

偏振剪切相机直接测量曲率和扭率

本文提出一种新的剪切相机,它可同时记录三个或四个错位的像。用相干光照明该剪切干涉系统可直接测量试件的二阶位移导数。     

斜光轴剪切散斑干涉法

本文提出了斜光轴剪切散斑干涉法。利用该方法可以单独地,直接获得物体离面位移的各项导数,避免了因分离各项导数而引入的误差,从而使得剪切散斑干涉法的应用更加简便,精确。同时为位移导数的分离提供了新的途径。     

采用多准直光束测量六自由度微位移新方法

为实现星载三线阵CCD相机的相机参数在轨测量,提出了一种六自由度微位移测量方法。高亮度LED输出光被准直并耦合到输入光纤。输出光纤末端固定在可移动的被测物体上。光纤输出由多个光纤准直器（ 4）准直,并由系统固定部分中的多个区域阵列的CCD相机（ 4）捕获。根据CCD图像中光点的位置变化来求解被测物体的六自由度位移。为了验证系统模型和六自由度位移计算程序,对该方法进行了理论分析和仿真。结果表明:当平移位移小于100 m且旋转位移小于6'时,典型的4准直测量系统求解误差小于10-5 m和10-4'。并且,当准直器的光斑位置的两个坐标方向上添加-0.5~0.5 m的随机量时,平移误差和旋转误差的3分别为0.9 m和0.012'。     

偏振扫描相机测量二维动态热形变场

提出了利用偏振扫描相机进行激光散斑照相，研测了物体的二维热形变场。全部动态过程的信息可记录在同一张散斑图上，且在全场滤波时可连续再现热形变物体的二维变形信息。     

旋转孔径锥镜剪切白光散斑照相法

利用旋转孔径技术和锥镜剪切技术进行白光散斑剪切照相，检测动态位移导数场。     

含Rashba自旋轨道耦合二维电子气结构中电子反常位移及自旋分离

研究了含Rashba自旋轨道耦合的磁电调制半导体二维电子气中弹道电子的反常位移 （Goos-H?nchen位移,即GH位移）。计算中发现,通过调节结构的各个参数包括入射角、磁场强度和Rashba自旋轨道耦合系数,可以有效地调控GH位移,并且在一定条件下可以为负。电子的GH位移和自旋极化态有密切关系,这个自旋相关的位移可以用来分离不同自旋极化的电子束。基于这种现象,提出了一种利用GH位移在半导体2DEG中分离不同自旋极化电子的方法。     

Experimental and theoretical study of semi-active friction tendons

For purposes of mitigating vibrations, a Semi-Active Friction Tendon (SAFT), which consists of a semi-active friction damper and an auxiliary spring that are linked to the structure by a cable, is studied experimentally, numerically and analytically. Two semi-active control laws are implemented, one is based on velocity-feedback (denoted as SQDCL) and the other is based on force-feedback (denoted as SPCL); the passive control case is also studied for comparison. From the assessment of system displacement and hysteretic behaviour of SAFTs two main conclusions are drawn. First, the effectiveness of the optimized passive-control case can always be improved by using semi-active control with any of the studied control laws. Second, the SPCL is more effective for large displacements, while the SQDCL is more advantageous for very small displacements. Moreover, closed-form expressions for the dissipated energy are derived for the three cases under consideration. These expressions can be used in preliminary design of SAFTs to compare with other alternatives, to decide between passive and semi-active control, and to choose the more suitable control law.     

Single-mode optical fibre tapers for self-aligned beam expansion

We demonstrate that optical fibre tapers can be utilised as a new means for achieving self-aligned beam expansion in single-mode fibres. These devices, which have a standard single-mode geometry at one end and gradually increase to a core size in the order of 100 ?m at the other end, have greatly reduced sensitivities to lateral and axial displacements and an excess coupling loss between two tapers of less than 0.1 dB.     

Double Beams to Measure Three-dimensional Rigid Body Displacements

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Kinematics of the Beating Heart

We introduce a new approach to the quantification of myocardial strain. It utilizes the theoretical frame work of kinematics and can thus account for the large time-varying displacements present in the intact beating heart. For arbitrary small segments of myocardium, we show how these displacements can be described completely by a rotation tensor and a stretch tensor. We demonstrate the physiologic meaning of this analysis in an anesthetized dog. An epicardial region was seen to exhibit a local twist quantified by the rotation tensor and a segmental shortening quantified by the stretch tensor.     

Lattice dynamics in wide band gap materials based superlattices

Lattice dynamics calculations in zinc blende group III nitrides superlattices were carried out assuming the existence of interface regions with variable thickness. The acoustic frequencies were observed to remain practically unchanged for all values of interface thickness from one to three monolayers. The dispersion relation, Raman spectrum and the atomic displacements of optical modes were found to be greatly affected by interfacing. Several Raman peaks shift toward the center position of the spectrum with increasing interface thickness. As a consequence, some of the Raman frequencies become quasi-coincident giving rise to highly prominent structures in the middle range spectrum. Effects of localization of atomic displacements at the interface regions are shown.     

微加工悬臂梁在横向冲击下的响应分析

分析了微加工悬臂梁在横向冲击下的响应．将悬臂梁看作一个质量分布参数系统,利用模态叠加法计算悬臂梁在冲击下的位移和应力分布,并根据位移和应力的最大值判断悬臂梁可能的失效模式,从而为MEMS器件的可靠性设计提供依据．     

Exponential Fourier densities on S2 and optimal estimation and detection for directional processes

Two classes of probability densities, the exponential Fourier densities and the exponential trigonometric densities, are introduced on the unit sphere, as well as four kinds of displacements. In general, neither class is closed under the operation of taking conditional distributions with respect to any of the displacements. A combined usage of both classes is required to study the estimation and detection models obtained from various combinations of the displacements. The merits and disadvantages of each model are discussed. Recursive formulas for the conditional densities and the likelihood ratios are derived for many of the models. The additive measurement noise case is also considered in detail. An error criterion for direction estimation is presented with respect to which the optimal estimates can be easily computed from the probability distribution. A deficiency of the models and techniques developed in this paper is that random driving terms are disallowed in the signal processes.     

Interpolation using the discrete sine transform with increased accuracy

The accuracy of interpolation using the discrete sine transform can be greatly improved by mapping the sequence to one which satisfies zero boundary point conditions. The accuracy may be increased if the mapped sequence also satisfies the boundary requirements for second-order derivatives.<>