And some of them might be spinning clockwise, in which case, according to the right-hand rule we would consider them spin-down.

而另一些电子则是在顺时针自旋，在这种情况下，根据右手定理,我们会以为它是在向下转。

麻省理工公开课 - 固态化学导论课程节选

So what that means is that we're limited in any atom to having two electrons per orbital, right, because for any orbital we can either have a spin up electron, a spin down electron, or both.

这意味着在一个原子内,每个轨道上可以有两个电子，对吧，因为对任何轨道,我们可以有自旋向上或者自选向下或者两者都有。

麻省理工公开课 - 化学原理课程节选