Specific activity Specific activity Specific activity is the activity per quantity of a radionuclide and is a physical property of that radionuclide. Activity is a quantity related to radioactivity. The SI unit of activity is the becquerel (Bq), equal to one reciprocal second. The becquerel is defined as the number of radioactive transformations per second that occur in a particular radioactive isotope. Its related non-SI unit equivalent is the Curie (Ci) which is transformations per second. Since the probability of radioactive decay for a given radionuclide is a fixed physical quantity (with some slight exceptions, see changing decay rates), the number of
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