测量误差理论与术语定义的发展与变化

阐述了测量误差理论的发展历程与发展方向,回顾了与误差理论和数据处理相关的国家计量技术规范跟随国际计量技术规范发展的过程,分析了国家计量技术规范中主要误差术语定义的变化情况和变化趋势。术语定义的变化表明：术语变化的趋势更具有严密的科学性、逻辑性和可操作性。     

Sphere mass center determination by velocity modulation

This paper presents a new technique, called velocity modulation, for measuring the mass center location of a sphere, improving upon the accuracy of previous methods by at least a factor of 4. The sphere is rolled down a set of parallel rails. The offset of the sphere’s mass center with respect to its geometric center modulates the sphere’s velocity at the rolling frequency, which is detected by a series of differential optical shadow sensors. The measured times that the sphere crosses the sensors is compared with a simplified mechanics model in order to recover the sphere’s mass center location. The precision of the technique is demonstrated by the repeatability of independent measurements in one plane of a 50.8 mm (2 in.) stainless steel gage sphere. The best standard deviation achieved is 145 nm (95% confidence interval = 227 nm).     

液体闪烁核活度计量仪

本文描述用液体闪烁计数法直接测定α、β发射体溶液放射性活度的计量仪器。该仪器包括三个光电倍增管的符合探测器和三个输出计数道;以三重对两重符合计数率之比(TDCR)为猝灭参数,通过外推效率曲线至TDCR=1直接得到核素的活度。该仪器用于放射性活度绝对测量至少有两个突出的优点:1.精确度较高,对~3H、~(63)Ni和~(14)C等多种β、α核素其总测量不确定度(3σ)在0.5—1.5％;2.操作简便,测量迅速。     

Distortions induced in turbine blades by hot forging and cooling

Geometrical distortions of hot forged thin components are one of the main causes that force process designers to work with significant allowances. Their identification in the early stages of process design would permit changing the process parameters in order to compensate them during cooling after the hot forging process.This paper presents a novel approach to evaluate geometrical distortions of hot forged components characterized by complex and thin geometrical features, such as turbine blades. A thermo-mechanical–metallurgical model of both the forging and cooling phases is developed, in order to investigate the effects of different cooling rates after forging on the component final geometry and then to choose those cooling parameters that assure minimal distortions. The developed models are calibrated through extensive experimental campaigns, involving both laboratory experiments and on-field measurements during industrial productions. Thermal boundary conditions are identified through on-field measurements of blade surface temperatures, while material behaviour regarding flow stress determination and phase transformation-related parameters is obtained through compression and tensile tests with a dilatometer aid, all carried out in the range of temperatures of interest for the forging and the cooling phases.     

Quantification of tool wear using white light interferometry and three-dimensional computational metrology

Although several wear modes can result from machining, the most common tend to be what are referred to as flank wear and crater wear. Flank wear can be easily measured directly from images of a worn cutting tool, and this is the typical method used to quantify the condition of a tool. On the other hand, crater wear is difficult to quantify, and thus has typically been treated in a qualitative manner. The inability to characterize and compare the two wear modes in a quantitative way is an increasingly important problem as the precision of machining operations improves and cutting moves almost exclusively to the nose radius of cutting tools. This paper introduces a new approach to this problem by proposing a technique to quantify both wear modes for direct comparison. The technique measures the volumetric wear loss in the two regions by comparing three-dimensional wear data obtained by white light interferometry with ideal representations of unworn cutting tools. The resulting wear measurements are compared and related to changes in the cutting process, specifically increases in cutting forces and changes in the topography of machined surfaces.     

Results of the NIST National Ball Plate Round Robin

This report examines the results of the ball plate round robin administered by NIST. The round robin was part of an effort to assess the current state of industry practices for measurements made using coordinate measuring machines. Measurements of a two-dimensional ball plate (240 mm by 240 mm) on 41 coordinate measuring machines were collected and analyzed. Typically, the deviations of the reported X and Y coordinates from the calibrated values were within ± 5 μm, with some coordinate deviations exceeding 20.0 μm. One of the most significant observations from these data was that over 75 % of the participants failed to correctly estimate their measurement error on one or more of the ball plate spheres.     

几何量测量标准建标的几个问题

就几何量测试标准建标，不确定度评定，重复性，稳定性，验证实验及实例进行论述。     

Fundamental physical constants and systems of units for physical quantities

Fundamental questions of contemporary metrology connected with redefinition of the basic units of physical quantities are discussed. Some new definitions of the kilogram, ampere, Kelvin, and mole are suggested and their consequences are analysed. The possibility of fixing some fundamental physical constants at the level of accuracy contemporary for 2011 is considered. Alongside the practical system of units, use of a fundamental (theoretical) system is proposed. The importance is noted of considering possible variations of physical constants for a fundamental system of units, whereas in practical metrology these variations are not currently essential. __________ Translated from Izmeritel’naya Tekhnika, No. 1, pp. 3–7, January, 2007.     

半导体激光器特性对衍射测量影响的理论分析

半导体激光器发出的是一束发散的椭圆形高斯光束，并具有温度依赖性。本文以细丝衍射测量系统为例，讨论半导体激光器上述特性对测量精度的影响，并提出消除这些影响的方法。     

A Genetic-Based Vision System for Cross-Functional Integration in Flexible Manufacturing: A Tutorial and Application

Machine vision has the potential to significantly impact both quality and productivity in automated manufacturing, due to its versatility, flexibility, and relative speed. Unfortunately, algorithmic development has not kept pace with advances in vision hardware technology, particularly in the areas of analysis and decision making. In this article, a tutorial is presented that explains how a genetic algorithm can be applied to vision systems for shape analysis and quality assessment. The control parameters for the algorithm are optimized by conducting experiments of Taguchi's approach to parameter design. The main objective behind this algorithm is to explain an application of the vision system that uses upstream design data of machined parts of different types for downstream metrology and quality decision making in the environment of flexible manufacturing. The part types used for demonstration are restricted to planar polygonal profiles generated by projecting 3D objects onto a 2D inspection plane. The input to the system is a set of boundary features of the part being analyzed, and the outputs from the system include the estimators of size, orientation, position, and out-of-profile error of the part. The system can analyze machined parts of different types without modifying software programs and parameter settings, which makes it generic and flexible, and is inherently suitable for on-line implementation in FMS environments.