智能测量系统中测量结果的自动计量支持

系统地探讨了智能测量系统中计量保证的一些紧迫问题，即表述（选择、评估、检定和报告）计量特性；最终测量结果不确定度的自动在线评定（称为测量结果的自动计量支持MAS）；自动计量支持手段的校准测试以及集成测量软件环境的具体实现方法。也提出了智能测量系统的实际定义，并给出其通用功能模块结构。     

逆向反射镜光度测量

为了正确评价逆向反射镜的加工质量与使用效果，且将二者有机地统一起来，本文提出应根据测试目的来选择合适的光度测量方法，并进一步分析了不同测试目的将导致测量装置的组成、几何条件（距离，孔径角，工作姿态等）、光度条件（光源色温、稳定性与均匀性，接收器线性、灵敏度与光谱修正等）、测量参数（反光强度系数、逆反射系数、逆亮度系数等）等各不相同。     

高温超导器件用于物理特性测量

美国量子设计公司、HTS-110公司和美国超导公司共同开发出一台仪器，该仪器装有由、高温超导（HTS）线制成的电磁线圈，用于测量材料的基本物理特性。     

主动测量信息处理的智能化

本文提出了一种对被测变量测量值所需信息进行了智能化处理方法，在线辨识出表征传感器滞后特性的时间常数Ｔｍ，再利用校正（补偿）的方法减少或消除滞后特性的影响，以减少或消除动态误差，使测量与控制融为一体，实现主动测量技术的全盘自动化。     

GTEM室内场强分布的计算分析

本文深入研究了近年来在电磁兼容测量及场强测量中广泛应用的吉赫横电磁室（ＧＴＥＭ），讨论了室内场分布的计算机算法，给出了６ｍ室的计算与测量实例。计算结果与测量结果符合较好。     

测量不确定度实际应用讲座（二）：测量不确定度的评定方法

本文依据BIPM，IEC，IFCC，ISO，IUPAC，IUPAP，OIML七个国际组织于1993年制定并于1995年修订的“测量不确定度表达指南（GuidetotheExpressionofUncertaintyinMeasarement）”，对测量不确定度的计算和表达方法作一介绍。1．常用术语与定义测量不确定度（uncertaintyofmeasarement）：与测量结果相关联的参数，表征合理地赋予被测量值的分散性。标准不确定度（standarduncertainty）：用标准偏差估计值表示的不确定度。A类标准不确定度（typeAstandarduncertainty）或标准不确定度的A类计算方法（typeAevaluationofstandard…     

激光多普勒技术与直线度测量

在三坐标测量机（ＣＭＭ）及精密加工机床等设备的高精度测量中，主轴及导轨的直线度、水平或竖直偏摆角的测量是相当重要的。在过去，这类机器的直线度的测量，大部实现起来比较困难，或者精度很低且费时。这里我们将介绍一种直线度测量的新方法，采用双光束系统的激光多普勒测量仪（简称ＬＤＤＭ），通过测量每一点的偏摆角，并按一定的准则计算出直线度。下面将分别简述有关的原理、精度及与其它测量方法相比较的优越性．由于这种测量技术可以对位移和角度进行同时测量，使得直线度实现了在线测量，这就为三维坐标测量仪器的精度拟合及代替线性编码器进行位置和直线性的标定提供了简易高效的新方法．     

激光自动跟踪空间坐标测量系统的发展（二）

DevelopmentofLaserAutomaticTracingSpaceCoordinateMeasurementSystem(2)WangJia;LuGang（上接1997年17卷第3期第39页）3多站激光跟踪测量系统3．1多边注的四站三自由度测量系统3.1.1四站三自由度测量系统1991年，日本O．Nakamura建立了采用多边法的四站三自由度测量系统。所谓多边法（multi-lateration）是用多台激光干涉仪共同跟踪一个反射器，计算坐标时只利用测量得到的长度改变量信息，而不用角度信息。对比前边的球坐标测量法，它有如下优点：（1）由于利用方向角的测量值来计算三自由度坐标。因此，球坐标测量法的测量精度随…     

电子计数式转速表设计中存在的问题及改进方案

一、存在的问题 目前，工程中使用的绝大多数手持电子计数式转速表在前面板上都设有存储显示按键“MEMORY”。该键的功能是，在一个测量过程结束后，第一次按下该键．转速表显示本次测量过程中自动存储的最后测量值“LA”（“LA”与对应的数值交替出现）；第二次按下该键，转速表显示本次测量过程中自动存储的最大测量值“UP”（“UP”与对应的数值交替出现）；第三次按下该键，转速表显示本次测量过程中自动存储的最小测量值“DN”（“DN”与对应的数值交替出现）。     

改进大孔径测量设备的新方法

在机械加工生产过程及现场，一般常用内径千分尺、内径表测量孔径。由于测量设备受测量力结构和加工工件装夹及加工设备多种因素的直接影响，造成测量数据不可靠。如我厂衍星磨加工，椭圆度锥度≤0．05mm，孔径深度230mm箱体，加工设备磨头与孔径内边缘最大间距40mm，磨头端面与孔径端面距离为170mm（图1）。选用内径表测量受空间限制，使用内径千分尺测量随意性大，测量准确度低，因此我们针对上述问题研制了杆式内径百分表，其结构见示意图（图对。使用此表可进行直接测量，解决上述测量不准确等问题。1．杆式内征百分表的结构和使用原理…     

Phase retrieval in digital speckle pattern interferometry by use of a smoothed space-frequency distribution

We evaluate the use of a smoothed space-frequency distribution (SSFD) to retrieve optical phase maps in digital speckle pattern interferometry (DSPI). The performance of this method is tested by use of computer-simulated DSPI fringes. Phase gradients are found along a pixel path from a single DSPI image, and the phase map is finally determined by integration. This technique does not need the application of a phase unwrapping algorithm or the introduction of carrier fringes in the interferometer. It is shown that a Wigner-Ville distribution with a smoothing Gaussian kernel gives more-accurate results than methods based on the continuous wavelet transform. We also discuss the influence of filtering on smoothing of the DSPI fringes and some additional limitations that emerge when this technique is applied. The performance of the SSFD method for processing experimental data is then illustrated.     

Speckle interferometry for analysing anisotropic thermal expansion—application to specimens and components

This paper describes a non-destructive optical technique, digital speckle pattern interferometry (DSPI), that has been developed particularly for strain analysis and has proved well suited for thermal deformation measurement. Fibre-reinforced composites with both metal and polymer matrices have been analysed by DSPI to determine their thermal expansion behaviour as a function of direction and temperature. Complete series of measurements can be performed quickly and without any restriction on the specimen shape. Engineering components including composite structures have been the subject of investigation. Besides quantitative results, real-time observation provides basic information for materials understanding.     

Noise reduction in digital speckle pattern interferometry using bidimensional empirical mode decomposition

We propose a bidimensional empirical mode decomposition (BEMD) method to reduce speckle noise in digital speckle pattern interferometry (DSPI) fringes. The BEMD method is based on a sifting process that decomposes the DSPI fringes in a finite set of subimages represented by high and low frequency oscillations, which are named modes. The sifting process assigns the high frequency information to the first modes, so that it is possible to discriminate speckle noise from fringe information, which is contained in the remaining modes. The proposed method is a fully data-driven technique, therefore neither fixed basis functions nor operator intervention are required. The performance of the BEMD method to denoise DSPI fringes is analyzed using computer-simulated data, and the results are also compared with those obtained by means of a previously developed one-dimensional empirical mode decomposition approach. An application of the proposed BEMD method to denoise experimental fringes is also presented.     

利用水下散射场测量橡胶弹性模量的方法研究

橡胶是减振降噪的主要材料之一,对其材料性能的掌握是进行结构设计的前提,针对中高频率下橡胶材料弹性模量测量标准的空白,提出一种新的测量方法。在自由场条件下,通过测量橡胶球的散射声场,计算散射场的勒让德展开系数,建立反演模型,求解橡胶球的声学参数,再根据材料参数之间的转换关系来获得弹性模量。实验结果表明,所测橡胶球的动态弹性模量在中高频上的变化规律与已知的结论一致,目标的反演散射声场与测量的散射声场符合较好。     

Effect of particle packing structure on the elastic modulus of wet powder compacts analyzed by persistent homology

This study applies persistent homology (PH) to the structural analysis of wet powder compacts to clarify the effect of packing structure on the elastic modulus, and proposes an equation for the relationship between saturation and elastic modulus based on the index of structural homogeneity. The relationship between the saturation and the elastic modulus was experimentally obtained by compression tests of wet powder compacts. The elastic modulus decreased linearly with increasing saturation, but the slope was different depending on the packing structure of compacts which were made from high purity alumina with different particle size distributions. PH was applied to the packing structure of particles of different diameters calculated by DEM simulation to evaluate the packing structure. The features of each packing structure were extracted by PH, and the index of structural homogeneity was obtained. A new empirical equation is proposed which can predict the relationship between the elastic modulus and the saturation considering structural homogeneity, specific surface area, surface tension, and porosity as the main factors affecting the elastic modulus in the partially saturated state. These results indicate that PH analysis is effective to evaluate the packing structure and that this method may predict the mechanical properties of wet powder compacts.     

Inclusion interaction and effective material properties in a particle-filled composite material system

This work presents a methodology implementing random packing of spheres combined with commercial finite element method (FEM) software to optimize the material properties, such as Young’s modulus, Poisson’s ratio, and coefficient of thermal expansion (CTE) of two-phase materials used in electronic packaging. The methodology includes an implementation of a numerical algorithm of random packing of spheres and a technique for creating conformal FEM mesh of a large aggregate of particles embedded in a medium. We explored the random packing of spheres with different diameters using particle generation algorithms coded in MATLAB. The FEM meshes were generated using software MATLAB and TETGEN. After importing the databases of the nodes and elements into commercial FEM software ANSYS, the composite materials with spherical fillers and the polymer matrix were modeled using ANSYS. The effective Young’s modulus, Poisson’s ratio, and CTE along different axes were calculated using ANSYS by applying proper loading and boundary conditions. It was found that the composite material was virtually isotropic. The Young’s modulus and Poisson’s ratio calculated by FEM models were compared to a number of analytical solutions in the literature. For low volume fraction of filler content, the FEM results and analytical solutions agree well. However, for high volume fraction of filler content, there is some discrepancy between FEM and analytical models and also among the analytical models themselves. The discrepancy is attributed to the multi-body interaction effect of the filler particles when they are getting close.     

Nondestructive Techniques for Studying Fracture Processes in Concrete

Some laboratory nondestructive evaluation techniques have been invaluable in studying fracture processes in concrete. Several nondestructive evaluation methods including acoustic emission (AE), computer vision, digital speckle pattern interferometry (DSPI), and X-ray microtomography (XMT) were used to examine the fracture behavior of concrete in tension and compression. Acoustic emission testing was used in an attempt to characterize the fracture properties of individual microcracks. As the specimens were loaded, AE waveform data was recorded, and analyzed for source location and source characterization. While DSPI analysis is limited to the specimen surface, the resolution is detailed such that microcracks on the order of 0.25 μm can be detected. Computer vision is a very useful method to measure crack openings for multiple crack development. It also can be used in conjunction with a hydraulic testing machine, which often generates vibration problem for some sensitive techniques. Crack patterns in cement-based materials under various material compositions and testing conditions are examined. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of a preconditioned conjugate-gradient algorithm for weighted least-squares unwrapping of digital speckle-pattern interferometry phase maps

Inasmuch as current fringe analysis techniques used in digital speckle-pattern interferometry (DSPI) yield a phase map modulo 2pi, phase unwrapping is the final step of any data evaluation process. The performance of a recently published algorithm used to unwrap DSPI phase maps is investigated. The algorithm is based on a least-squares minimization technique that is solvable by the discrete cosine transform. When phase inconsistencies are present, they are handled by exclusion of invalid pixels from the unwrapping process through the assignment of zero-valued weights. Then the weighted unwrapping problem is solved in an iterative manner by a preconditioned conjugate-gradient method. The evaluation is carried out with computer-simulated DSPI phase maps, an approach that permits the generation of phase fields without inconsistencies, which are then used to calculate phase deviations as a function of the iteration number. Real data are also used to illustrate the performance of the algorithm.     

压入法测定金属材料的杨氏模量

综述了无破坏法测定金属杨氏是的测定原理、测定方法和测定仪器并对这种测定方法进行了误差分析。     

中高频段下的粘弹性材料声学参数测量

为了实现粘弹性材料在高频段上的声学参数测量,提出一种自由场测量方法,通过测量目标的水下散射声场指向性,计算目标散射场声压的前几阶勒让德系数,建立以目标的材料声学参数为变量的数学模型,并运用遗传算法进行参数反演.仿真结果表明以铝球的杨氏模量(E)为例,不存在声场误差的情况下反演精度可达0.0014%,铝球散射场的实验数据也提供了较高的参数反演精度.将此方法应用于中高频段上某种成分的粘弹性材料参数测量,成功地获取了其在此频段上的声学参数.提高目标散射场的测量精度有利于目标材料反演精度的提高.此方法避免了对声压相位的测量,减少了影响精度的因素.