It would have had a hard time getting through the shields and it didn't have any distance.

几乎没法穿过盾牌,也没有远程杀伤力

耶鲁公开课 - 古希腊历史简介课程节选

Now, that's a very important point, because why in the world would you give a shield of the kind I am describing, for a man to defend himself, if you imagine him standing by himself anywhere, if you imagine him any distance from the rest of the guys fighting alongside of him.

这点非常关键,那就是到底为什么要将,这样一种盾牌,给士兵们使用,想象一下这个场景,这个士兵在战场的某个角落孤军奋战,与其它友军士兵相隔甚远

耶鲁公开课 - 古希腊历史简介课程节选

So, basically what we're saying is if we take any shell that's at some distance away from the nucleus, we can think about what the probability is of finding an electron at that radius, and that's the definition we gave to the radial probability distribution.

本质上我们说的就是,如果我们在距离原子核,某处取一个壳层，我们可以考虑在这个半径处,发现电子的概率，这就是我们给出的,径向概率密度的定义。

麻省理工公开课 - 化学原理课程节选