isotope exchange rate

例句：

1. 1. The researchersused a technique to measure the isotopes in the sample.
   研究人员使用了一种技术来测量样本中的同位素。
2. 2.The isotopes were found to be different from those in the surrounding environment.
   发现这些同位素与周围环境的不同。
3. 3.The isotopes were used to study the behavior of the molecules.
   这些同位素被用来研究分子的行为。