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零点和水的三相点的关系有一段历史,可以简单地敍述如下:1927年以前,零点的定义是在一个大气压下,水和冰平衡时的溫度,而假設水和冰体系里完全沒有空气。根据这样約定义,水的三相点(冰和水在水的蒸气压下的平衡溫度)是0.0075℃。实际上,在一个大气压的空气下,冰和水的体系里不可能沒有空气,而空气在水中的存在就会降跃零点。这就会使零点随溶入水中的空气的多寡而变化。因此,1927年国际度量衡会議拟出一个新的零点定义:“零点是細小的純冰和在一个大气压下被空气所飽和的純水成平衡时的溫度。”这个零点是肯定值,沒有1927年以前的零点的毛病。根据这个定义,黄子卿等直接測出水的三相点的溫
There is a history of the relationship between the zero point and the three-phase point of water, and can be briefly described as follows: Before 1927, the zero point was defined as the temperature at equilibrium of water and ice at one atmosphere and assuming there was absolutely no air in the water and ice system . According to this definition, the triple point of water (the equilibrium temperature of ice and water at the vapor pressure of water) is 0.0075 ° C. In fact, under one atmosphere of air, there can be no air without ice or water, and the presence of air in water can drop by zero. This will change the zero with the amount of air dissolved into the water. Therefore, the International Metrology Conference of 1927 proposed a new zero point definition: “The zero point is the temperature at which the fine pure ice equilibrates with the pure water saturated with air at an atmospheric pressure.” This zero is a positive value, without the 1927 Zero points before the problems. According to this definition, Huang Ziqing directly measure the temperature of the water’s three-phase point