The SI - Fundamentally better
国际单位制（SI）—根本性飞跃
国际单位制（SI）是被世界各国普遍采用的单位制，适用于所有的测量应用。SI的目标之一是为测量提供长期稳定的基础，但它本身并非一成不变，SI一直是一个既注重实际又不断发展的动态体系，不断运用最新科技成果完成自身的变革。
2018年11月，国际计量大会在凡尔赛召开。大会通过了SI自1960年创立以来最重大的变革。这使SI重新构建在我们当前对自然法则的最高认知上，同时消除了SI与基于实物原器的定义之间的关联。“以量子现象建立基准”的测量新方法是此次变革的原动力，它使SI发生了根本变革。
2018年11月通过的SI变革，将于《米制公约》签署的周年纪念日，即2019年5月20日“世界计量日”起正式生效。此次变革对未来的影响深远，我们一直高度重视，以确保在变革生效之际，新定义与现行定义是兼容的。除了要求极高的用户外，其他用户将不会注意到此次变革引起的变化，但变革确实意味着：最终，溯源性的建立方式可能会发生改变。与此同时，协调全球测量仪器运行的工作也在不断推进中，它将确保贸易界、工业界和消费者使用任何重量、长度及其它量时，不会感受到与变革前存在任何不同。
新定义“运用自然法则建立测量规则”，将原子和量子尺度的测量与宏观层面的测量关联起来，实现了“米制”的共同夙愿——为全球测量提供普遍适用的基础。新定义还为未来的测量创新奠定了基础，使秒、米、安培和开尔文定义利用原子和量子现象不断提高准确度水平，达到人类观测能力的极限。
“The SI – Fundamentally better”
The International System of Units (SI) is the accepted set of units for all applications of measurement worldwide. Although one of its aims is to provide the basis for measurements that are stable over long periods of time, it has always been a practical and dynamic system that has changed to exploit the latest scientific advances.
In November 2018, the General Conference on Weights and Measures met in Versailles and agreed one of the most significant sets of changes to the SI since its inception in 1960. These were to base it on our best understanding of the laws of nature and to eliminate the link between the SI and definitions based on physical artefacts. The changes build on the results of research into new measurement methods that use quantum phenomena as the basis for standards that are fundamental.
These changes were agreed in November 2018 and come into force on May 20th 2019, a date chosen because it is the anniversary of the signature of the Metre Convention, celebrated by World Metrology Day. Whilst the future impact of the changes will be far reaching, great attention has been paid to ensure that the new definitions will be compatible with the current ones at the time the change is implemented. The changes will not be noticeable to any but the most demanding users, but, they do mean that there may be changes in the way that traceability is ultimately established. The global work to harmonize the operation of instruments used to make measurements will continue to ensure that trade, industry and consumers will not notice any difference to the weights, lengths and other measures they use.
The new definitions use ‘the rules of nature to create the rules of measurement’, linking measurements at the atomic and quantum scales to those at the macroscopic level. They achieve a collective ambition for the “metric system” which has been to provide universality of access to the agreed basis for worldwide measurements. They will provide the basis for future innovations in measurements that will allow the definitions of the second, the metre, the ampere and the kelvin to take advantage of atomic and quantum phenomena to achieve levels of accuracy limited only by our capacity to observe them.