ODM2 Units Type Controlled Vocabulary ODM2 Working Group A vocabulary for describing the type of the Unit or the more general quantity that the Unit represents. Specific radioactivity Specific activity is the activity per mass quantity of a radionuclide and is a physical property of that radionuclide. [Wikipedia: https://en.wikipedia.org/wiki/Specific_activity] Quantum Mechanics CUAHSI http://dbpedia.org/page/Specific_activity