sodium doublet lines

例句：

1. 1.The sodium doublet lines in the spectrum are used to identify different elements.
   在光谱中识别不同元素的钠双线。
2. 2. Scientists have been able to observe sodium doublet lines in space.
   科学家已经能够在太空中观察到钠双线。
3. 3. The sodium doublet lines in the spectrum are used to determine the temperature of the object.
   光谱中的钠双线被用来测定物体的温度。