LPG加气机检定仪的校准及不确定度评定

论述了LPG加气机检定仪的校准依据、方法、设备和程序，并进行了测量不确度评定。实验结果表明：影响加气机检定仪校准结果的不确定因素主要包括LPG液体温度、压力、平衡蒸气压、瞬时流量、加气机检定仪的分辨力、温度补偿以及压力补偿。此外，通过测量结果的不确定度评定亦表明：基于称重法的LPG流量标准装置的设计原理正确，测量准确度高，完全可满足加气机检定仪的检定和校准要求。     

LPG加气机检定仪的检定

本文简要论述了LPG加气机检定仪的检定技术法规、加气机检定仪组成、技术要求和计量性能要求,并且叙述了加气机检定仪的检定程序。     

液化天然气加气机流量示值误差的测量不确定度评定

作为加气机测量结果的一个重要技术指标,有必要对液化天然气加气机流量测量结果的不确定度进行分析评定,本文依据JJG 1114—2015《液化天然气加气机》检定规程,介绍了对液化天然气加气机流量示值误差测量的不确定评定过程。     

液化石油气(LPG)加气机检定中需注意的问题

目前上海、辽宁等地的液化石油气(LPG)加气机(以下简称LPG加气机)地方检定规程,对测试流量点的确定均参照燃油加油机。由于LPG与汽油、柴油等成品油的物理性质有很大区别,所以,参照燃油加油机的检定方法对LPG加气机进行检定会存在诸多问题。以容积法为例,对有可能出现的问题分析如下:     

压缩天然气（CNG）加气机检定结果不确定度评定

在生态文明的大背景下,作为清洁能源的天然气广泛应用于汽车燃料中,为汽车充装天然气的CNG加气机已全面应用于CNG加气站。随着云南省加气机数量越来越多,云南省计量院为了适应社会需要,建立了压缩天然气加气机检定装置项目。建立该项社会公用计量标准目的意义是为了加强强检计量器具的管理,保障压缩天然气（CNG）加气机量值传递的一致性、准确性,保护经营者和消费者的合法利益,确保计量法在压缩天然气加气机领域的贯彻实施。该文依据JJG996-2012《压缩天然气加气机检定规程》结合现场数据,对加气机各个不确定度分量进行分析,最终确定压缩天然气加气机测量结果的不确定度。     

液化天然气(LNG)加气机测量不确定度评定

LNG作为工业生产中一种重要的能源,发挥着越来越重要的作用。在过程中对于LNG的计量也越发具有意义。依照JJG1114—2015《液化天然气加气机检定规程》的要求,结合计量测试值,对加气机各个不确定度分量进行分析,最终确定LNG加气机不确定评定结果。     

降低发动机试验稳态压力测量不确定度方法研究

为降低系统不确定度,分析试验台稳态压力测量系统的各不确定度来源,对降低稳态压力测量系统不确定度的重要因素进行分析并提出相应改进方法。采用压力传感器现场校准方法降低测量系统与检定系统差异引入不确定度,采用三次样条插值法对压力传感器进行温度补偿降低工作环境温度对压力传感器影响引入不确定度。经验证,两种改进方法有效降低了系统的不确定度,该改进方法在其他型号发动机试验以及相关组合件试验中具有重要的推广和应用价值。     

液化石油气加气机示值误差测量结果的不确定度评定

本文根据国家计量检定规程JJG 997-2005《液化石油气加气机检定规程》分析在检定中各误差分量的构成,对示值误差测量结果的不确定度进行评定.     

液化石油气加气机的检定与不确定度评定

简要介绍了液化石油气加气机的检定方法，论述了液化石油气加气机检定中测量不确定度评定方法及具体的计算程序。     

加气机现存问题的调研检测及解决方案

介绍了LPG和CNG加气机的工作原理,并依据对加气机的检测结果,分析了加气机计量检定中存在的问题,并提出了解决问题的相应措施。     

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.     

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.     

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.     

可燃气体检测报警器测量结果的不确定度评定

本文详细介绍了可燃气体检测报警器示值误差测量结果的不确定度评定方法。     

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)。     

心电图机电压测量示值误差测量值的不确定度评定

本文介绍了心电图机电压测量示值误差测量值的不确定度评定与表示方法。     

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.