At low temperatures the difference in population of atoms between two energy levels, which is the basis of maser action, is greater.

在低温下，作为脉塞作用基础的两个能级之间原子数的差别较大。

youdao

At low temperatures, the difference in population of atoms between two energy levels, which is the basis of maser action, is greater.

在低温下，作为微波激射作用基础的两个能级之间原子数的差别较大。

youdao