长度计量技术浅析

长度计量在工业生产、日常生活中应用广泛,对技术的发展和进步作用巨大。文章介绍了长度计量技术的意义、任务、相关的原理和测量基础,阐述了常用的长度计量技术。     

小议现阶段长度计量技术

长度计量在工业生产、日常生活中应用广泛。对技术的发展和进步作用巨大。文章介绍了长度计量技术的意义、任务、相关的原理和测量基础,阐述了常用的长度计量技术。     

米定义的演变和发展

0引言几何量测量泛指与长度国际单位制(SI)米(m)有关的一切量,包括端度、量仪、角度平度、粗糙度、工程测量等。而狭义的长度计量是指距离测量,也是其他物理量计量的基础,许多物理量是通过长度计量来实现的。随着近代工业生产力的发展进步,长度计量在各不同阶段得到了迅速发展和应用,也是历史上最早发展起来的计量技术之一。我国历史     

长度计量概述

长度计量是生产实践中最常遇的被测量之一,是计量技术的重要组成部分。主要任务是研究和确定长度单位的定义,建立和保存长度计量基准,开展长度检定、校准和测试,,以确保量值的统一、准确、可靠。本文就长度计量研究过程主要涉及的研究内容:长度单位,长度基准,及长度计量中不可忽视的误差项做一具体介绍。     

航空工业北京长城计量测试技术研究所大尺寸实验室

正航空工业北京长城计量测试技术研究所大尺寸实验室是集科研、产品研发、计量、型号、测试于一体的综合性实验室,专业从事国防科技工业测量领域中大尺寸测量技术、大尺寸测量设备校准和应用技术研究。大尺寸实验室的科研项目包括:1)开展大尺寸测量系统研究,满足大尺寸测量系统和设备的量值传递和溯源需求,开展大尺寸测量系统和设备的静态和动态校准技术研究,建立和逐步完善大尺寸长度、角度和坐标的国防最高计量标     

高端测长仪器设计原则在步距规校准仪设计中的应用

制造和测量过程的不断迭代是提升产品性能的关键,目前高端仪器自主研发能力不足使我国高端制造业的发展受到了制约.长度计量仪器是保障制造业量值溯源准确性的重要基础之一,本文以步距规校准装置的研制过程为例,介绍阿贝原则、最小变形原则、最短测量链原则在高端长度计量仪器设计中的具体应用,为高端长度计量仪器的研制提供技术借鉴,推动我...     

计量与物理应用技术及能源计量国际研讨会将在京举行

本刊讯为了加强现代计量与物理应用技术的国际、国内交流与合作，促进国内此领域基础理论及其应用技术的研究，中国计量科学研究院、中国科学院物理研究所、中国计量协会和发展中国家计量技术与产品信息网联合主办的“计量与物理应用技术及能源计量国际研讨会”将于8月19日至23日在北京举行。本次研讨会的研讨内容主要有：计量和物理学内容，包括国家计量标准的发展趋势、时间频率测量、量子基准的研究、高低频与微波测量、光学测量、电磁兼容与电磁保护、热工、长度测量；现代纳米技术的研究、超导技术、磁性测量的研究和应用、激光物理测…     

NIST:长度测量服务

正美国国家标准与技术研究院(NIST)物理测量实验室(PML)半导体和长度测量部的测量服务项目,专注于几微米至一米的测量,实现长度量值传递,提供促进美国创新、工业竞争力的测量、标准和基础的技术服务。NIST维护和开发先进的干涉系统,用于将基于频率的SI长度单位复现传递到实物上。推动三坐标机的技术发展、开发用来定量评价三坐标机特性的方法,通过引领和参与活动,对于国际和国内长度计量提供积极支持。     

633 nm激光波长基准/副基准比对

对中国计量科学研究院、中国计量测试技术研究院和长城计量测试技术研究所的633 nm127I2饱和吸收稳定激光波长基准、副基准进行了比对,这是首次进行的国内长度基准的比对.比对实验的内容包括频率稳定度测量、频差测量和相关的位移参数测量等.给出了以国际计量局BIPM C1为参考的比对结果.     

浅谈量块的周期检定和检定周期

量块是由两个互相平行的测量面之间的距离来确定其长度的高精度量具,其长度为计量器具的长度标准。通过量块可以进行长度的量值传递,又可以作为计量标准器对长度计量测试仪器、量具、量规等进行检定,还可以直接测量和调整精密机床的夹具、刀具在加工中的定位尺寸或对精密机械零件尺寸的测量。所以量块对长度计量单位的统一和量值传递的准确可靠都起着重要的作用。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。