1875年“米制公约”签署时,计量仅仅是以长度和质量为研究对象,上世纪20年代,计量工作扩展到对电学计量单位和计量标准的研究,至60年代,电离辐射被纳入其研究范围,至90年代,化学又成为计量研究新的领域。一个多世纪后的今天,科学技术、工业贸易、人类文明的发展速度和进步程度 When the Metering Convention of 1875 was signed, the measurement was only based on length and quality. In the 1920s, the measurement work was extended to the study of the electrical measurement units and measurement standards. By the 1960s, ionizing radiation was included in the scope of its study By the 1990s, chemistry has become a new area of ​​metrology research. More than a century later, the speed and progress of science and technology, industrial trade and the development of human civilization