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

Real life for both humans and animals involved cases where the reinforcement doesn't happen all the time but actually happens according to different schedules.

在现实中，人类和动物,并不总是不停的得到强化,但实际上强化则是根据不同的时程出现的。

耶鲁公开课 - 心理学导论课程节选

And fixed versus variable speaks to whether you give a reward on a fixed schedule, every fifth time, or variable, sometimes on the third time, sometimes on the seventh time, and so on.

固定与变化则是相对于,你是否根据固定时程给予奖励而言的，每五次就给予奖励，或者是变化的，有时候在第三次上给予奖励，有时候则在第七次上给予奖励。

耶鲁公开课 - 心理学导论课程节选