余氯比色计法与DPD分光法测定水中余氯的比较研究

本文对N,N-二乙基-1,4-苯二胺(DPD)光度法和余氯比色计法测定余氯进行比对研究。文中DPD分光法采用余氯标准溶液建立标准曲线,余氯比色计法采用仪器内置曲线。DPD分光法操作相对繁琐,更适用于实验室各类送检水样的定量测量。余氯比色计检测水中余氯,则是现场快速检测的有效手段。     

滤光光电比色计吸光度测量结果的不确定度评定

本文介绍了滤光光电比色计吸光度测量结果的不确定度评定的一种方法.     

余氯测定仪的校准

介绍HI系列比色法余氯测定仪的校准方法,提出了须校准项目及其技术要求,并对示值误差测量值的不确定度进行了分析评定,得出示值误差测量值的不确定度为0.03 mg/L,k=2。     

ASTM D1500色度计校准结果的不确定度评定

ASTM D1500色度计主要用来测量各种润滑油、煤油、柴油、石油蜡等大多数石油产品的颜色。参考罗维朋比色计的校准方法对ASTM D1500色度计的校准方法进行了研究。并对校准结果进行测量不确定度评定。     

DPD滴定法测定水中余氯的不确定度评定

对DPD滴定法测定水中余氯进行了不确定度评定。对标准物质、样品称量、溶液定容体积、滴定体积等引入的不确定度分量进行了分析和量化,计算了合成不确定度及扩展不确定度。     

混响室法测量吸声系数的不确定度评价

通过对材料吸声系数混响室法测量分析,确定了该类方法测量结果不确定度的来源。对不确定度构成分量进一步分析,结果表明吸声系数的测量不确定度主要由混响时间测量的不确定度所决定,混响室体积、试件尺寸和声速测量的不确定度对吸声系数测量结果的不确定度贡献很小。混响时间测量结果的不确定度主要取决于混响室声场扩散程度,而测量装置本身引入的不确定度贡献较小。     

测量不确定度在实验室中的应用

测量不确定度,是近年来对测量结果的误差表述。论述了测量不确定度的分类,哪些场合需进行不确定度分析,影响不确定度的因素,及测量不确定度的评定实例。     

声校准器测量结果的不确定度评定

本文依据JJG176-2005《声校准器》检定规程,找出对声校准器测量准确性影响的不确定度因素,确定声校准器测量准确性与不确定度来源之间的关系。用适当的方法确定各不确定度来源的不确定度,根据《测量不确定度表示指南》,测量不确定度传播定律,计算出被测声校准器的测量不确定度。     

二等砝码折算质量修正值测量不确定度评定

本文首先确定被检砝码 (二等砝码 )量的特性 ,找出对被检砝码测量准确性影响的不确定度因素 (来源 ) ,确定被检砝码测量准确性与不确定度来源之间的关系。其次用适当的方法确定各不确定度来源的不确定度。最后根据《测量不确定度表示指南》 ,测量不确定度传播定律 ,计算出被检砝码的测量不确定度。     

浅谈测量不确定度及在评判测量系统能力中的应用

文章详细阐述了测量不确定度的定义、测量不确定度的计算方法及步骤、测量不确定与测量能力的关系,以"三坐标测量光孔和螺纹孔位置度"为例,具体讲述了测量不确定度和测量能力的计算方法及如何利用测量不确定度评价测量系统适用性的方法.     

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)。