原子质量数

锶的放射性同位素（原子质量数为），存在于核爆炸的原子尘中，能象钙一样被吸收到骨中。

A radioactive isotope of strontium ( with the mass number 90 ) that is present in the fallout from nuclear explosions ; can be assimilated like calcium into bones .

铀的同位素，原子质量数为，能进行持续的连锁反应。

A uranium isotope with mass number 235 ; capable of sustaining chain reactions .

具有放射性的钴的同位素，原子质量数为，一种能量极高的伽马放射源，用于放射疗法。

A radioactive isotope of cobalt with mass number 60 ; a source of exceptionally intense gamma rays ; used in radiation therapy .

最后系统地研究了Pb和Ni这两条同位素链的共振态性质，发现两条同位素链的单粒子共振态能量都随原子核质量数的增加而减小。

We have investigated in details the properties of the or Pb and Ni isotopes , and found that the energies and widths of the resonant states decrease with the increasing of the nuclear mass number for the two chains .