| 1. | The rate at which radioactive elements disintegrate varies from one element to another .
放射性元素的衰变速度随元素种类的不同而不同。 |
| 2. | The decomposition of a radioactive element is the simplest example of a true first order reaction .
放射性元素的衰变是真正一级反应最简单的实例。 |
| 3. | Petrographically and mineralogically similar rocks quite often have different concentrations of radioactive elements .
岩石学矿物学上类似的岩石，其放射性元素丰度却往往有所不同。 |
| 4. | " in recognition of their synthesis of new radioactive elements
合成了新的放射性元素 |
| 5. | Radium and uranium are radioactive elements
镭和铀是放射性元素 |
| 6. | A naturally occurring or artificially produced radioactive element
放射性元素自然产生或人为制造的放射性元素 |
| 7. | Inorganic chemicals ; organic or inorganic compounds of rare - earth metals , of radioactive elements or of isotopes
无机化学品；稀土金属，放射性元素及其同位素之有机及无机化合物 |
| 8. | Inorganic chemicals ; organic or inorganic compounds of rare - earth metals , of radioactive elements or of isotopes
无机化学品；稀土金属，放射性元素及其同位素之有机及无机化合物 |
| 9. | I shall now speak to you of the experiments which have led us to obtain by transmutation new radioactive elements
我现在跟诸位讲讲那些使我们通过蜕变法获得新的放射性元素的实验。 |
| 10. | Geological dates are usually obtained by using the rates of decay of various radioactive elements found in minerals
人们通常用矿物中所发现的各种放射性元素的衰变率来计算地质年代。 |
