液氮冻制冰套法对水三相点温度的影响

介绍了液氮作为冷却剂在水三相点容器内冻制冰套的方法。利用该方法同时在两个不同真空度的水三相点容器内分别冻制冰套。通过实验，研究了此方法对所复现的水三相点温度的影响。实验结果表明：冻制过程中产生的应力以及开始生成的小冰晶引起水三相点温度偏低；并且，其对水三相点温度的影响随着水三相点容器内真空度的降低而增大。随着应力慢慢消除，小冰晶逐渐长大为大冰晶，所复现的水三相点值逐渐回升并趋于稳定。因此，为了高精度复现和准确测量水三相点，采用该冻制方法时，必须将冰套老化至少5天以后，才可以消除其对水三相点温度的影响。

Effect of Liquid-nitrogen Freezing Method of Preparation of Ice Mantle on the Triple-point Temperature of Water

A method of preparation of ice mantle in triple point of water (TPW) cell by means of liquid-nitrogen as coolant is described. The mantles are simultaneously formed in the two TPW cells of different vacuums, respectively, and the experimental investigation of effect of the freezing method on the realized triple point temperature of water is carried out. Experimental results show that the introduction of strains in ice and formation of fine ice crystals during preparation of the mantle resulted in the observed temperature decrease. Additionally, the effect increased with the decrease of vacuum in the cell. As the stresses are gradually relieved and the fine ice crystals slowly converted into bigger ice crystals, the realized temperature increased to a certain extent and then has a tendency to keep constant. Therefore, in order to precisely realize and measure the TPW, it is required that the mantles must be aged at least 5 days to make the effect eliminated.