Shielding is the term that's used, it brings up a certain image in our mind, and even though that's not precisely what's going on, it's a very good way to visualize what we're trying to think about here.

它带给我们一个确定的画面，虽然那不够精确，但当我们尝试去考虑它的时候,它确实是一种很好,的形象化的方式。

麻省理工公开课 - 化学原理课程节选