alpha particle

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++ˈalpha ˌparticle noun [countable] technical  an atomic particle consisting of two protons and two neutrons that is sent out by some radioactive substances α粒子，阿尔法粒子〔包含两个质子和两个中子，由某些放射性物质释放〕

ˈalpha ˌparticle nounChineseSyllable  

alpha particle
ˈalpha ˌparticle noun [countable] technical
an ATOMIC PARTICLE consisting of two protons and two neutrons that is sent out by some radioactive substances

alpha particleBrE /ˈælfə pɑːtɪkl/ 🔊NAmE /ˈælfə pɑːrtɪkl/ 🔊 noun (specialist) the nucleus of a helium atom; a particle with a positive electrical charge, that is produced in a nuclear reaction * α 粒子