对《校准厚度片测量不确定度评定》一文的探讨

对《校准厚度片测量不确定度评定》一文评定方法中直接测量法与比较测量法的区分,数显电感测微仪示值误差的选用,通过有效自由度评定扩展不确定度的方法进行了探讨。     

(0～100)mm数显千分尺示值误差测量结果的不确定度评定

本文介绍了(0~100)mm数显千分尺示值误差测量结果的不确定度评定方法。     

电线电缆绝缘厚度测量不确定度的评定

对电线电缆绝缘厚度的测量进行了测量不确定度评定。通过对测量不确定度有主要影响的3个分量即读数的分散性、仪器的最大允许示值误差和环境温度影响的不确定度评定得出了标准不确定度依次为:0.00234mm、0.00231mm、0.00032mm;合成标准不确定度为0.0033mm。     

电子数显指示表示值误差测量结果的不确定度评定

本文介绍了用全自动光栅式指示表检定仪检定数显指示表示值误差测量结果的不确定度评定方法。     

数显测高仪示值误差的测量不确定度评定

针对数显测高仪各校准点示值误差的校准方法,给出了示值误差的测量模型,并以某校准点为例,对该校准点示值误差的合成标准不确定度和扩展不确定度进行了评定。     

游标卡尺示值误差的测量不确定度分析与线性拟合

正一、引言由于JJG30-2012《通用卡尺检定规程》中并没有给出游标卡尺示值误差的测量不确定度来源分析和计算方法示例,检定员在日常工作中使用起来非常不方便。因此,本文举例分析游标卡尺示值误差的测量不确定度来源,同时给出具体的计算过程,并且通过分析游标卡尺各段示值误差的测量不确定度,利用线性回归方程,对该测量不确定度进行了线性拟合,给出了整个测量范围内测量不确定度的函数表达式。     

覆层厚度测量仪示值误差测量不确定度评定

该文旨在规范覆层厚度测量仪测量不确定度分析与评定工作,确保测量不确定度评定结果的准确可靠。该文运用国际通用不确定度评定方法,建立测量模型,对以标准厚度片作为标准器校准覆层厚度测量仪示值误差进行了测量不确定度评定,并分析其不确定度分量,以期为广大测量人员提供不确定度分析参考依据。     

超声波测厚仪示值误差测量不确定度评定

本文旨在规范超声波测厚仪示值误差测量不确定度分析与评定工作,确保测量不确定度评定结果的准确可靠。运用国际通用不确定度评定方法,建立测量模型,对以标准厚度块作为标准器校准超声波测厚仪示值误差进行了测量不确定度评定,并分析其不确定度分量的各个来源。     

机械公法线千分尺示值误差测量不确定度的线性拟合

由于JJG 82—2010《公法线千分尺》中没有机械公法线千分尺示值误差测量不确定度的分析,所给的不确定度分析也没有线性拟合,故文章通过分析机械公法线千分尺各段示值误差的测量不确定度,利用回归方程,对该测量不确定度进行了线性拟合,给出了整个测量范围内测量不确定度的函数式,便于使用者应用。     

镜片测度表示值误差的测量不确定度评定

本文介绍了镜片测度表的用途与原理,运用测量不确定度评定与表示方法,对镜片测度表示值误差的测量值的不确定度进行了评定,详细分析了测量过程中的各分量对示值误差的影响,最后得出测量值的扩展不确定度。     

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.     

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.     

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.     

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)。