Becquerel Becquerel The becquerel (; symbol: Bq) is the SI derived unit of radioactivity. One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The becquerel is therefore equivalent to an inverse second, s. The becquerel is named after Henri Becquerel, who shared a Nobel Prize in Physics with Pierre and Marie Curie in 1903 for their work in discovering radioactivity. As with every International System of Units (SI) unit named for a person, the first letter of its symbol is uppercase (Bq). However, when an SI unit is spelled out
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