Of the hydrogen nuclei, 26 out of every million were deuterium.
在氢原子核中,百万分之 26 个是氘。
What Happens If – Verge Science
In the starts, fusion occurs when hydrogen nuclei fuse to form helium.
一开始,聚变发生在氢核聚变形成氦时。
英语百科
Hydrogen atom
A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the elemental (baryonic) mass of the universe.