n.镤(放射性化学元素)

Protactinium is a naturally occurring element with the atomic number 91.
钍是自然界中存在的一种元素，原子序数为91。
It was discovered by German chemist Hahn and Strassmann in 1917.
1917年，德国化学家哈恩和斯特拉斯曼首次发现了它。
Its radioactivity makes protactinium useful in various applications, particularly in nuclear reactors.
钍的放射性使其在各种应用中有用，特别是在核反应堆中。
Protactinium has a silvery-gray appearance and is highly radioactive.
钍呈现出银灰色，且具有高度放射性。
The half-life of protactinium-231, a common isotope, is about 32,760 years.
常见同位素钍-231的半衰期约为32,760年。
Due to its scarcity, protactinium is not found in large quantities in the Earth's crust.
由于其稀有性，地壳中找不到大量钍。
Its isotopes have been used as tracers in geology and hydrology studies.
钍的同位素被用于地质学和水文学的研究中作为示踪剂。
The decay of protactinium contributes to the formation of uranium.
钍的衰变有助于铀的形成。
Scientists study protactinium to better understand the processes in the early stages of nucleosynthesis.
科学家研究钍以更好地理解核合成初期的过程。
Although rare, protactinium can be extracted from phosphate rock for nuclear fuel applications.
尽管稀有，但可以通过磷灰石提取钍用于核燃料应用。