Alpha particles are these helium nuclei, and they are the result of radioactive decay.

阿尔法粒子是氦核，它们是放射性衰变的产物。

麻省理工公开课 - 固态化学导论课程节选

Suppose we've got some sort of radioactive atom, which has a certain chance of decaying.

假定我们有某种放射性原子,它们以一定的几率衰变

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And there are various forces that play in the nucleus that will dictate when this will be stable and when it won't be.They isolated it, but it decays very quickly on the order of microseconds Lifetime on the order of microseconds.

在原子核中有很多种力,都会产生作用，当条件是稳定的,还有当它不是的时候，它们提取出来，但是它会以微秒的速度衰变,生命只有几微秒长。

麻省理工公开课 - 固态化学导论课程节选