ra.di.o.ac.tiv.i.ty
n.(名词)Spontaneous emission of radiation, either directly from unstable atomic nuclei or as a consequence of a nuclear reaction.自动放射:自动地发出辐射,直接源于不稳定的原子核或是作为核反应的结果The radiation, including alpha particles, nucleons, electrons, and gamma rays, emitted by a radioactive substance.辐射:由一种放射性物质发出的辐射,包括α粒子、原子核、电子、和γ射线