infrared portion的用法和样例：
例句
- The range of the spectrum in which heat is radiated mostly lies within the infrared portion.
辐射热的光谱段大部分落在红外区。 - This expansion causes changes in the character of the emission over time, resulting in the time delay between the infrared and sub-millimetre flares.
这种膨胀导致了辐射的性质随着时间变化，结果就是红外波段和亚毫米波段的闪耀时延。
