In some kinds of beta decay, a nuclide loses surplus positive charge by emitting a positron (in the same event, a proton becomes a neutron, and neutrinos are also given off).

• 以某种贝它衰减，一个核素靠发出一个正电子失去剩余正电荷(在相同的事件中，一个质子变成一个中子，而且也发射微中子)。