Although the case is reminiscent of episodes from the Cold War, Russia hailed the exchange as a positive development.

VOA: standard.2010.07.09

So, for example, for the chlorine case, we would say that the electron affinity for chlorine is actually positive 349 kilojoules per mole.

比如，以氯为例，我们可以说氯的电子亲和能,应该等于正的，349，千焦每摩尔。

麻省理工公开课 - 化学原理课程节选

And we saw that in fact in this case delta S of mixing, we calculated it, saw that it is positive.

实际上如果我们计算气体混合过程中,熵的变化，我们会发现这个量是正的。

麻省理工公开课 - 热力学与动力学课程节选

You might say that optimists are people who think that for everybody in every case, in every circumstance, the total is always positive.

乐观主义者认为,任何人在任何情况下，在任何环境里，等式结果永远是正数。

耶鲁公开课 - 死亡课程节选

Often a good thing to start with is to put the lowest ionization energy atom in the middle, and if you don't have charge separation then go with that structure, but if you do find you have a lot of separation, such as the case in negative 2, positive 2, and minus 1, then you want to say wait a second, this is really bad in terms of formal charge, let me go ahead and see what other options I have here.

通常一开始把电离能最低的原子,放在中心位置就很好了，如果你发现电荷没有分开,那么这个结构就没问题了，但是如果你发现有很多分开的电荷，比如这种情况，有负二，正二和负一，那么你会想要说等一下，从形式电荷来看这很不好，让我去看看其它可能的选择。

麻省理工公开课 - 化学原理课程节选

So if delta v is negative, in this case delta v is negative, OK, delta v is negative, pressure is a positive number, negative times negative is positive, work is greater than zero.

也就是当活塞,压缩气体的时候，做的功是正的，按照这一规定,我们需要在这里，加上一个负号，这是习惯规定。

麻省理工公开课 - 热力学与动力学课程节选