共查询到19条相似文献,搜索用时 78 毫秒
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不同来源的水三相点容器的比对 总被引:1,自引:0,他引:1
本文介绍了水三相点在开尔文热力学温度和ITS-90国际温标中的重要地位.重点介绍了麦克劳式水三相点容器内冰套的冻制方法及水三相点的复现.同时,NIM与ISOTECH同种结构的水三相点容器进行比对.比对结果表明,不同来源的水三相点容器复现的水三相点值在±0.04mK范围内一致. 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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环境对水三相点温度的影响 总被引:3,自引:0,他引:3
本文通过实验研究了环境对水三相点温度的影响。实验结果表明 ,当环境温度为 2 0 5℃ ,环境热辐射引起所测量的水三相点值偏高约 0 1 4~ 0 1 7mK ;热辐射对水三相点温度的影响随着热辐射强度的增强而增大 ;在高精度复现、准确测量水三相点时 ,用黑布罩住温度计及水三相点容器口 ,可以消除环境热辐射的影响。 相似文献
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2 0 0 2年 1 1月由国际计量局组织的水三相点瓶的国际关键比对 (简称CCT -K7) ,中国计量科学研究院研制出新型结构的水三相点瓶。本文详细介绍了新型水三相点瓶 ,并将其与国家基准水三相点瓶进行了比对。同时 ,给出了比对结果。 相似文献
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In 2005, the National Institutes of Standards and Technology (NIST) and Fluke’s Hart Scientific Division initiated a study
to validate the isotopic correction algorithm applied to the realization temperature of triple point of water (TPW) cells.
Additionally, the study quantified the impact of water sample impurities on the TPW cell realization temperature. For this
study, eight TPW cells containing water of the same nominal isotopic concentration as Vienna Standard Mean Ocean Water (VSMOW)
were used. Five of the cells were manufactured with fused-quartz envelopes and the remaining three with borosilicate envelopes.
One TPW cell of each type was uniquely designed so that water samples could be periodically removed to analyze the isotopic
composition and to monitor any changes in water purity with time and thereby correlate changes in composition with changes
in realization temperature. The borosilicate TPW cells gave an average drift of −13 μK · yr−1 and the more stable fused-quartz TPW cells gave an average drift of −2 μK · yr−1. 相似文献
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X. K. Yan C. F. Ma Z. Zhang H. L. Wu P. Qiu Y. L. Feng J. T. Zhang Y. N. Duan 《International Journal of Thermophysics》2008,29(3):815-824
As the triple point of water is of great importance for the International Temperature Scale of 1990 (ITS-90) and for the definition
of the unit of thermodynamic temperature, its long-term stability has attracted a great deal of attention. In a study of long-term
stability, a mystery has been uncovered. Some triple-point-of-water cells remain stable for many decades, while others decrease
with increasing age of the cells, which is called long-term drift. To investigate this mystery, we used cells with different
manufacture dates ranging from 1974 to 2002 and compared their analyses, which were done in 1984 and 2003. Using the same
model of long-term drift as that used by Hill, the long-term drift rates of the two data sets are –4.7 μK·year−1 and –9.2 μK·year−1, respectively. One is consistent with the observed depression of about –4 μK·year−1 measured by Hill, whereas the other differs greatly from Hill’s result. In addition, corresponding factors influencing long-term
drift are discussed in this paper. 相似文献
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过冷水滴碰撞导线表面结冰机理的实验研究 总被引:5,自引:0,他引:5
导线覆冰是一种随机发生的自然现象,曾对电网的安全构成严重危害.目前人们对过冷水滴碰撞导线结冰过程机理认识尚不太清楚.文中对过冷水滴碰撞导线表面结冰机理进行了实验研究,通过对单一过冷水滴碰撞圆柱金属表面冻结的动态行为进行高速拍摄,揭示了该结冰过程形态特征,并从大量实验数据中分析得到了过冷水滴分别以2.2m/s和4.3m/s的速度撞击不锈钢、紫铜、铝等表面瞬时结冰边界条件的统计数据.同时还对过冷水滴流量从0.6滴/s到2.2滴/s,环境温度从-2℃~-8℃时导线覆冰增长动态过程影像及形态变化进行了研究和归纳分析. 相似文献
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X. K. Yan J. T. Zhang Y. L. Wang C. F. Ma Y. N. Duan 《International Journal of Thermophysics》2008,29(1):104-111
An investigation into the effects of isotopic composition on the triple point temperature of water has been carried out at
the National Institute of Metrology (NIM), China, since redefinition of the kelvin with respect to Vienna Standard Mean Ocean
Water (V-SMOW) was officially proposed by the Consultative Committee for Thermometry (CCT) in 2005. In this paper, a comparison
of four cells with isotopic analyses and relevant results corrected for isotopic composition, employing the isotope correction
algorithm recommended by the CCT, is described. The results indicate that, after application of the corrections, the maximum
temperature difference between the cells drops from 0.10 mK to 0.02 mK and that these cells are in good agreement within 0.02 mK.
Also, temperature deviations arising from isotopic variations fall in the range from −55.9 μK to + 40.7 μK. We consider that
the distillation temperature and degassing time of the production procedure lead to isotopic variations. 相似文献