共查询到20条相似文献,搜索用时 328 毫秒
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通过建立测量模型,分析了0.01级气体活塞式压力计计量标准主要不确定度分量,并进行评定,给出0.01级气体活塞式压力计计量标准的合成标准不确定度和扩展不确定度。 相似文献
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通协分析计算影响活塞式压力计表示值误差的不确定度分量,并进行有效合成,最后计算出活塞式压力计示值误差的扩展不确定度,并给出使用要求的结论。 相似文献
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介绍0.02级标准活塞式压力计检定0.05级活塞式压力计示值误差测量结果不确定度的评定方法。 相似文献
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本文依据JJG59-2007<活塞式压力计>检定规程对0.05级活塞式压力计进行不确定度评定. 相似文献
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本文根据国家计量技术规范JJF1059-1999<测量不确定度评定与表示>、国家计量检定规程JJG 59-2007<活塞式压力计>并结合实际工作经验,对0.05级活塞式压力计活塞有效面积测量结果不确定度进行评定. 相似文献
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提出了一种微小表压力(差压)测量的新方法。采用1台活塞式压力计和1台精密的数字压力计,通过关断阀连接高低压端的特殊连接方式实现微小表压力(差压)测量,解决了活塞式压力计由于受其下限值的限制而不能实现微小压力测量的问题。利用数字压力计较好的短期稳定性以及活塞式压力计较低的不确定度,可以实现1~10kPa微小表压(差压)的校准,其校准结果的扩展不确定度为U=2.2Pa(k=2)。 相似文献
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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. 相似文献
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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. 相似文献
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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)。 相似文献
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Liebert A Wabnitz H Grosenick D Möller M Macdonald R Rinneberg H 《Applied optics》2003,42(28):5785-5792
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. 相似文献
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