| 释义 |
甲种粒子jiǎzhǒng lìzǐ某些放射性物质衰变时放射出来的氦原子核,由两个中子和两个质子构成,质量为氢原子的四倍,速度每秒可达两万公里,带正电荷。穿透力不大,能伤害动物的皮肤。{alpha particle; positive charged particle given off by certain radioactive substances, which consists of two protons and two neutrons (a helium nucleus) and is converted into an atom of helium by the acquisition of two electrons, its mass being four times that of an atom of hydrogen with a speed of 20,000 kilometres per second and having little piercing power but harmful to the skin of animals;}也叫also阿尔法粒子{ɑ'ěrfǎ lìzǐ}。 |