倒角测量仪示值误差校准方法研究

在没有检定方法可参照的情况下,通过深入研究倒角测量仪的结构、测量原理及功能,结合对多种同类型百分表检定的经验,利用国内常用的全自动指示表检定仪,研究并得出其示值误差校准的一种新方法。对实现其校准过程的透彻分析帮助检定人员充分理解进口指示表与国内指示表在技术要求上存在的差异,为检定人员提供了一种全新思路。     

厚度指示表校准方法

厚度指示表作为一种常用计量器具,在实际校准过程中由于没有国家校准规范,给工作带来不便。本文根据实践经验提出了厚度指示表的校准项目及方法,基本满足厚度指示表校准的需求。     

浅析压力校验仪的选择

压力表的校准是通过压力发生器产生压力,压力校验仪作为压力的指示值,来对被检表进行计量校准的过程,但是目前很多技术人员在进行压力设备建标时,压力校验仪的选取不是非常清楚,该文通过举例说明,压力校验仪的选取规则。     

指示表检定仪示值误差校准新方法探究及实践

全自动光栅指示表检定仪已成为目前市场上校准指示类量具的主流产品,然而,以量块为标准器的校准方法很难满足这类仪器校准的需要。本文给出了一种基于高精度长度计的仪器示值误差校准方法,通过试验及不确定评估验证了方法的可行性。     

指示量具校准结果不确定度评定

分析指示表误差来源,对指示表校准结果不确定度进行了评定。     

大量程数显千分表示值误差测量方法讨论

正JJG34-2008《指示表(指针式、数显式)检定规程》适用于量程不大于10mm的数显指示表;JJG379-2009《大量程百分表检定规程》只能针对百分表进行测量;GB/T18761-2007《电子数显指示表》适用于分辨力为0.001mm、测量范围上限为30mm的电子数显指示表。这就意味着行程为50mm甚至150mm的大量程数显千分表的示值误差没有有效的溯源方法。笔者根据自身经验,参考相关文献,针对大量程千分表示值误差的校准方法与     

长度计量基础知识讲座(二十三)

<正>第二十三讲指示类量具检定仪1概述指示类量具检定仪是用于检定或校准指示表(千分表和百分表)、杠杆表和内径表的示值误差和回程误差的计量标准器具。通常使用的指示     

无线压力采集仪校准装置研究

无线压力采集仪使用环境温度与常规测量仪表存在较大差异。为解决无线压力采集仪在不同温度下的压力校准需求,设计了无线压力采集仪校准装置。该装置采用了三段控温的干式恒温炉以及自动压力调节,实现了各温度下的压力自动校准。试验结果表明:该装置功能及测量不确定度满足现有无线压力采集仪的校准对装置的要求,可应用于无线压力采集仪的校准。     

关于表面温度计校准方法的优化和研究

表温度计主要用于测量、指示物体表面或具备一定温度的环境内某重要部件的表面温度,对产品加工及后期质量有着至关重要的作用。但在JJF 1409—2013《表面温度计校准规范》中对表面温度计校准操作要求比较模糊,因此表面温度计的测温准确度始终是个难题。通过本课题的设计研究,对测温原理研究及测温装置设计,较为有效地减小表面温度计校准过程中测温间隙与压力所带来的不确定度,从而提高了表面温度计对温度进行监测的数据准确度,同时通过各项试验,对表面温度计校准规范的校准方法中较为模糊的地方进行量化,规范了表面温度计校准操作程序,提高了工作效率。     

模拟油井校准系统原理及应用

为保证存储式油井测压器在高温高压高冲击的实际环境中测试的精度,根据新概念动态测试理论,研制模拟油井校准系统。该系统能模拟石油井下高温高压的测试环境,并在该环境下对测压器进行动态校准,从而避免了实验环境与校准环境不同引起的精度差异。模拟油井校准系统可提供静压力为0MPa～50MPa(表压);承受的脉冲压力峰值为0MPa～150MP(a表压);工作温度为25℃～200℃。     

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.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

卧式金属罐容量的测量结果不确定度

本文根据多年的实践检定经验 ,参照JJF1 0 59- 1 999《测量不确定度评定与表示》以及《测量不确定度表达 1 0讲》 ,对卧式金属罐容量的测量结果不确定度进行了评定。     

盐酸浓度不确定度的评估

通过对盐酸浓度标定的过程分析，找出影响结果的各个分量，进行不确定度的评定，按照计量技术规范给出标准的表示法。     

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.     

Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials

An analysis of anisotropy of the properties of a Bi₂Se_0.3Te_2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied.