共查询到20条相似文献,搜索用时 78 毫秒
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由于可燃性气体并非由单一气体构成,因此,对于检定可燃气体报警器用何种标准气体作为检定介质,是我们需要探讨的问题。JJG693—2004《可燃气体检测报警器》计量检定规程规定,检定可燃气体报警器使用的标准气体是异丁烷和丙烷,但使用这两种气体对可燃气体报警器进行检定,会给一些生产企业带来不便。在此,我们拟通过可燃性气体的等热值特性,解决选择多种标准气体作为可燃气体报警器检定介质的难题。 相似文献
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特种气体是由两大类气体组成的。一类为单元高纯气体,另一类为混合气体。对于单元高纯气体,根据现已收集到的文献,汇总起来共有227种,可分成五个类别。 相似文献
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要保持有毒和有危险性气体用超净气体系统的可靠性在半导体制造业中,使用的气体处理系统可分为三类:自燃/可燃、腐蚀性/毒性和惰性。当系统中的杂质与工艺气体相结合时,常常会出现问题。自燃气体,如硅烷(SiH4),当它暴露在室内空气中时,可以发生爆炸反应。它... 相似文献
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半导体用气大多是可燃性、腐蚀性极强的气体。一些带有剩余的毒性、腐蚀性或可燃性气体的钢瓶,由于长期存放或被忽视,加之气候影响而被腐蚀。腐蚀严重者会出现泄漏。可燃性气体的泄漏,能引起爆炸和火灾。毒性气体的泄漏,会给人的健康、生命造成很大的危害。因此,已严重腐蚀的钢瓶中的剩余气体如不及时排放掉,将是严重的危害隐患。 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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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。 相似文献