中文翻译与英英解释

【原子能】半衰期〔放射性同位素分裂[从生物体中排出]一半量的时间〔也作 half life 或 half life period〕〕。

the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)
同义词：half life,

Half-life (t?) is the time required for a quantity to fall to half its value as measured at the beginning of the time period. In physics, it is typically used to describe a property of radioactive decay, but may be used to describe any quantity which follows an exponential decay.

例句与用法

It has a half-life of about 41/2 billion years .
它的半衰期大约为45亿年。

The half-life of francium is 22 minutes .
钫的半衰期是22分钟。

Evolutionists have recently learned that groups of species also have what might be called a half-life .
进化论者最近发现生物属种也具有一种可以称为半死亡期的时期。