1. The rarefaction of natural resources has become a global concern.
自然资源的开采已经成为全球关注的问题。

2. Infrared rarefaction is a technique commonly used in thermal imaging.
红外稀释是热成像中常用的技术。

3. The rarefaction of the sugar solution resulted in a decrease in sweetness.
糖溶液的稀释导致了甜味的降低。

4. The rarefaction of air molecules in the vacuum chamber was necessary for the experiment.
实验中，真空室内的气体分子的稀疏是必要的。