1、It had been used for practical ends, to identify elements and to unravel radioactive decay chains.
已將其用于實踐的目的，去鑒別元素和闡明放射性衰變系。

2、Helium is the by product of millennia of radioactive decay from the elements thorium and uranium.
氦是釷和鈾元素數(shù)千年放射性衰變的副產(chǎn)品。

3、The point of the experiment is that radioactive decay is a quantum process.
這項實驗的關鍵因素在于放射性衰變是一個量子過程。

radioactive decay翻譯