SI base unit referenced to the values of the fundamental constants, namely the Planck constant ("h"), the electron charge ("e"), the Boltzmann constant ("k"), and the Avogadro constant ("N"). This approach was approved in 2018, only after measurements of these constants were achieved with sufficient accuracy. SI base unit The International System of Units (SI) defines seven units of measure as a basic set from which all other SI units can be derived. The SI base units and their physical quantities are the meter for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin
Khai Si Khai Si Khai Si () is a sub-district ("tambon") in Mueang Bueng Kan District, in Bueng Kan Province, northeastern Thailand. As of 2012, it had a population of 5,294 people. It lies on Highway 212 and the Mekong River and border with Laos, west of Bueng Kan and east of Ho Kham. The sub-district was created in 1979, when nine administrative villages were split from Nong Sawang sub-district (then still named Nong Kheng) to form the new sub-district. The sub-district is divided into 10 administrative villages ("muban"). The sub-district municipality Khai Si is the local government unit responsible for the