國際單位制（SI）—根本性飛躍

國際單位制（SI）是被世界各國普遍采用的單位制，適用于所有的測量應用。SI的目標之一是為測量提供長期穩定的基礎，但它本身并非一成不變，SI一直是一個既注重實際又不斷發展的動態體系，不斷運用最新科技成果完成自身的變革。

2018年11月，國際計量大會在凡爾賽召開。大會通過了SI自1960年創立以來最重大的變革。這使SI重新構建在我們當前對自然法則的最高認知上，同時消除了SI與基于實物原器的定義之間的關聯。“以量子現象建立基準”的測量新方法是此次變革的原動力，它使SI發生了根本變革。

创盈 2018年11月通過的SI變革，將于《米制公約》簽署的周年紀念日，即2019年5月20日“世界計量日”起正式生效。此次變革對未來的影響深遠，我們一直高度重視，以確保在變革生效之際，新定義與現行定義是兼容的。除了要求極高的用戶外，其他用戶將不會注意到此次變革引起的變化，但變革確實意味著：最終，溯源性的建立方式可能會發生改變。與此同時，協調全球測量儀器運行的工作也在不斷推進中，它將確保貿易界、工業界和消費者使用任何重量、長度及其它量時，不會感受到與變革前存在任何不同。

新定義“運用自然法則建立測量規則”，將原子和量子尺度的測量與宏觀層面的測量關聯起來，實現了“米制”的共同夙愿——為全球測量提供普遍適用的基礎。新定義還為未來的測量創新奠定了基礎，使秒、米、安培和開爾文定義利用原子和量子現象不斷提高準確度水平，達到人類觀測能力的極限。

“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. 

创盈 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. 

创盈 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.

创盈 文章來源：中國計量網

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