一、引言虽然约瑟夫森效应取代标准电池作为电动势的参考基准,实际上在世界上正常地实现约瑟夫森效应标准的研究所不到10个。甚至在这些研究所中标准电池也用在两次约瑟夫森效应测量之间保存电动势标准并用来同其它研究所进行电动势比较。现在一次约瑟夫森效应测量的典型过程是 I. INTRODUCTION Although the Josephson effect replaces a standard battery as a reference for electromotive force, less than 10 studies have been conducted that actually implement the Josephson effect standard in the world. Even standard cells in these institutes are used to preserve the electromotive force standard between two Josephson effect measurements and to compare electromotive force with other research institutes. A typical Josephson effect measurement is now a typical process