Part II—Explicit-Constant Definitions for the Kilogram and for the Mole

摘要

The proposals for the new SI recommended by the CIPM involve using the fundamental constants h, e, and NA as three of the reference constants that would take fixed values in the new SI. The details of the proposed changes to the definitions of the units are explained in greater detail in reference 1. The overall effect of the changes will be to reduce the uncertainty with which almost all of the fundamental constants of physics are known by more than an order of magnitude, as shown in the table of uncertainties to the right.' In the new SI proposed by the CIPM, the unit of mass, in addition to all the other SI units, will be referenced to a true invari-ant of nature rather than a prototype artifact whose mass is known to be varying, perhaps by more than a part in 107 since it was adopted over a century ago.