Realization of the triple point of carbon dioxide evaluated by the ITS-90
Realization of the triple point of carbon dioxide evaluated by the ITS-90
复制标题
DOI：
10.1088/1681-7575/ab451e
复制
发表时间：
2020-02-01
期刊：
影响因子：
2.4
通讯作者：
Nakano, Tohru
中科院分区：
文献类型：
--
作者：
Kawamura, Yasuki;Matsumoto, Nobuhiro;Nakano, Tohru
我们使用带有5个胶囊型标准铂电阻温度计（SPRT）的绝热量热计对1990年国际温标（ITS-90）的二级参考点之一的二氧化碳（CO2）三相点进行了精确的温度测量。杂质分析表明，CO2样品的纯度为99.99937%。在实现三相点之前的热处理过程减小了CO2三相点的熔化曲线的宽度，并且增加了熔化曲线相对于熔化分数F的倒数的线性。我们通过外推热处理过程后获得的六条熔融曲线确定了CO2在液相线点的三相点温度。本文测得CO_2的三相点温度为216.59090K0.36mK（k = 1）。这一结果表明，CO2三相点有可能作为ITS-90的固定点来替代汞三相点。
We performed a precise temperature measurement of the triple point of carbon dioxide (CO2), which is one of the secondary reference points of the International Temperature Scale of 1990 (ITS-90), using an adiabatic calorimeter with five capsule-type standard platinum resistance thermometers (SPRTs). Impurity analyses showed that the purity of the CO2 sample was 99.999 37%. A thermal treatment process before the realization of the triple point reduced the width of the melting curve of the triple point of CO2 and increased the linearity of the melting curves with respect to the inverse of the melting fraction F. We determined the triple-point temperature of CO2 at the liquidus point by extrapolating the six melting curves obtained after the thermal treatment process. The triple-point temperature of CO2 measured in this work is 216.590 90 K 0.36 mK (k = 1). This result indicates that the triple point of CO2 can potentially be used as a fixed point based on the ITS-90 to replace the triple point of mercury.