half-life radioactive的意思|示意

A naturally radioactive carbon isotope with atomic mass 4 and half-life 5,780 years, used in determining the age of ancient organic, geologic, or archaeological specimens.

一种碳的天然放射性同位素，原子量为4，半衰期为5，780年，用于测定古代生物标本，地质标本或考古遗迹的标本的年代。

Radioactive iodine in food is of immediate concern, but it has a relatively short half-life and will naturally decay over a short time frame.

食品中的放射性碘直接引起人们的关注，但是它的半衰期相对较短并将在短时间内自然衰变。

When common cobalt (59Co) absorbs a neutron the result is 60Co, which is radioactive and has a half-life of more than five years.

当普通钴（59Co）吸收了一个中子后生成的是相对原子量60的钴。钴60有放射性且半衰期超过五年。

Most famously, uranium-238 decays into lead-206 with a half life of 4.5 billion years, though radioactive rubidium and samarium are also useful for dating things billions of years old.

最为有名的就是铀- 238衰变为铅- 206的半衰期为45亿年，当然放射性铷和钐也同样对测算几十亿年前的物体的年龄很有用。

A radioactive transuranic element in the actinide series, artificially produced in trace amounts. Its longest-lived isotope is No255 with a half-life of3 minutes. Atomic number102.

锘在锕类元素中的一种放射性超铀元素，人工微量制造，其最长寿命的同位素是锘255，其。

Radioactive iodine has a half-life of eight days and decays naturally within weeks.

放射性碘的半衰期为八天，几周内自然衰变。