Researchers say they observed shortages in the brain's reward system in patients with A.D.H.D.

VOA: special.2009.09.29

And if you work out the energetics as we've gone with thermochemistry, dH you discover there's a huge negative delta H.

如果你计算能量变化,就像在化学热力学中所作的一样，你会发现很大的负的。

麻省理工公开课 - 热力学与动力学课程节选

So, for example, down here I wrote that it was n 2 and that it was h 2, but when I re-wrote the molecules up here, you saw that it's an h h single bond where it's a nitrogen-nitrogen triple bond.

比如，在这下面我写的是氮分子2,而这个是氢分子，但我在上面把这些分子的形式改写了，大家可以看到,这是一个氢与氢之间的单键，含一个氮与氮之间的三键。

麻省理工公开课 - 化学原理课程节选

Sixty-five thousand H-1Bs are awarded each year to graduates with a bachelor's degree.

VOA: special.2009.07.02

So, I just want to write a few examples down with a few values for delta u or delta H or delta S, and see whether we can get any clues from what we see.

我先写一些例子,例子包含一些内能，自由焓和熵的变化数值，然后看从中,我们能不能得到一些启示。

麻省理工公开课 - 热力学与动力学课程节选

In a .h file, it's generally the names of functions other people wrote.

在头文件里,只有一些函数名。

哈佛公开课 - 计算机科学课程节选

This is a painter called Frans Hals, H-A-L-S.

这是画家法兰斯·霍斯的作品

耶鲁公开课 - 欧洲文明课程节选

So, we see that the two h atoms separate have a certain energy that's lower than when the electron's not with the atom.

那么，我们看到两个分开的氢原子所具有的能量,比原子中没有电子时更低。

麻省理工公开课 - 化学原理课程节选

C H 3 So any time you see c h 3 here, remember that that's methyl and that's going to be a terminal group.

因此一旦你看到，记得这就是甲基,而且只能在结构的末端。

麻省理工公开课 - 化学原理课程节选

So I show that here, so in green, you have what's called a carboxcylic acid group, a c o o h, which gets converted by s o c l 2 to a c double bond o c l or an acid chloride.

我在这里用绿色表示，我们所说的羧酸族化合物，碳，氧，氧，氢，它被亚硫酰氯转化为,一个碳氧双键与碳氯单键组成的酰氯。

麻省理工公开课 - 化学原理课程节选

H2 So the simplest case we can think of is with h 2 where we have two unpaired electrons, each in a 1 s orbital of a separate h atom.

最容易想到的例子是2,我们有两个未配对电子，每个都在一个分开的1s轨道上。

麻省理工公开课 - 化学原理课程节选

Unfortunately, this is also call the Rydberg constant, so it's a little bit confusing. But really it means h the Rydberg constant divided by h, and that's equal to 3 .

不幸的是，它也叫Rydberg常数，所以这可能会有点混淆,但它表示Rydberg常数除以。

麻省理工公开课 - 化学原理课程节选

So if you're working with cyanide in the lab as potassium cyanide or sodium cyanide, those are what are called p h s's, it's a rating for different kinds of chemicals.

因此如果你在实验室中,需要用到氰化物，比如氰化钾或者氰化钠，这就是所谓的，“P，H，S“,这是化学药品有害程度的一个级别。

麻省理工公开课 - 化学原理课程节选

So it has a bond, there's no bond in h e 2.

所以在He2里没有键。

麻省理工公开课 - 化学原理课程节选

In some sense, that's one reason to associate this as a kind of energy, H just like mechanical energy u or enthalpy H, it's the minimum free energy state that is the equilibrium state under the relevant conditions.

在某种意义下，这是我们把这些物理量称为能量的原因，就像机械能U和自由焓，具有最小自由能的状态在特定的条件下,就是平衡态。

麻省理工公开课 - 热力学与动力学课程节选

The more important thing that I want you to notice when you're looking at this wave equation for a 1 s h atom, is the fact that if you look at the angular component of the wave function, you'll notice that it's a constant.

我要你们注意的,更重要的一点是,当你们看到,这个氢原子1s轨道方程的时候，如果你们看,波函数，的角向部分，你们会发现它是一个常数。

麻省理工公开课 - 化学原理课程节选