Some occur naturally because they have long half-lives .

有些存在于自然界中，是因为它们的半衰期很长。

It is common knowledge that irradiated cats have 18 half-lives .

众所周知，辐射猫有18个半衰期。（猫有九命，辐射猫即18个半条命。）

DDCM can give accurate theoretical half-lives for various decays of nuclei in a unified framework.

DDCM基于微观真实的核势和库仑势，可以在统一的框架下计算原子核的各种衰变模式的半衰期。

The washout period lasted at least five half-lives of the psychotropic medications taken by the patient before the study to ensure complete clearance from the body.

根据患者服用过的精神药物的不同，洗脱期持续至少5个半衰期。研究确保药物完全排除体外。