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

And there he was able to identify the alpha particle as the helium nucleus.

他证实了,阿尔法粒子就是氦核。

麻省理工公开课 - 固态化学导论课程节选

So, all that's left is the helium nucleus, two protons, two neutrons.

仅留下氦核，两个质子，两个中子。

麻省理工公开课 - 固态化学导论课程节选

We have a helium nucleus and one electron.

我们有一个氦核和一个电子。

麻省理工公开课 - 固态化学导论课程节选