What we define as zero is the enthalpy of every element in its natural state at room temperature and ambient pressure.

我们将零点定义为每种元素,在室温和正常大气压下,在其自然状态下的焓。

麻省理工公开课 - 热力学与动力学课程节选

So, actually I want you to go ahead in your notes and circle that zero point and write "not a node."

在你们笔记上把这个零点圈出来,在旁边写上“不是节点“,它不是节点“

麻省理工公开课 - 化学原理课程节选

You know, if you want to measure the potential energy of something in a gravitational field, you have to define the zero somewhere, right, because it's arbitrary. You can set it anywhere you want. It's the same with enthalpy.

你知道，如果你想测量重力场,中某种东西的势能，你需要，在某处定义一个零点，对吧？,因为势能的值是任意的,你可以把它设定在。

麻省理工公开课 - 热力学与动力学课程节选

So what we do is we pick an origin, call it zero, we put some markers there to measure distance, and we say this guy is sitting at 1,2,3,4,5.

我们现在选择一个原点,称其为零点,我们做一些标记来测量距离,这个点在五个单位长度的地方

耶鲁公开课 - 基础物理课程节选

t the new deal, s over , by the unemployment is down to close to zero by the middle of the War.

如果不是新政，If，it，wasn’,萧条结束，it’,失业率也降低到接近零点,在二战中的时候。

斯坦福公开课 - 经济学课程节选

It's much more relevant to set our zero point energy as the separation of a bond in terms of talking about the reactions that we'll usually be dealing with here.

更好的是把零点能定在,键断裂的时刻,在讨论化学反应的时候,而我们以后将经常遇到化学反应。

麻省理工公开课 - 化学原理课程节选

I want to point out that the zero energy is defined as when you have a naked proton -- where the electron has popped out -- that's what we've defined as zero energy up to this point when we're talking about single atoms.

我想指出，这里零点能的定义,是当我们只有一个裸露的质子,而没有电子时-,到目前为止对零点能一直采用这样的定义,当我们在讨论单个原子时。

麻省理工公开课 - 化学原理课程节选

So that's why we have this zero point here, and just to point out again and again and again, it's not a radial node, it's just a point where we're starting our graph, because we're multiplying it by r equals zero.

这就是为什么在这里有个零点，我需要再三强调，这不是径向零点，他只是我们画图的起始处，因为我们用ｒ等于０乘以它。

麻省理工公开课 - 化学原理课程节选

And what you see is that at zero, you start at zero.

你们看在零点处，它是零。

麻省理工公开课 - 化学原理课程节选

So I said before when we were talking about single atoms, we always define the zero energy as when an electron was actually ejected, but now, when we talk about chemical reactions taking place, it's very, very rare that we're actually going to be talking about anything that gets to this point here.

我之前说过，当我们讨论单个原子的时候，我们总是把零点能,定在电子被发射出去以后，但是现在，当我们讨论化学反应发生的时候，非常非常罕见出现，确实达到,这种程度的情况。

麻省理工公开课 - 化学原理课程节选

If that's all it knows, then in that scenario there is no building or anything else; it continues a trajectory both forward in time and backward in time, and it says that whatever seconds, one second before you set your clock to 0, it would've been on the ground.

如果是这样,在那种模式下,没有楼房或者别的什么,物体的运动轨迹可以沿时间可以向后延伸,也可以向前延伸,不管时间取什么值,在零点前一秒时,物体就在地面上

耶鲁公开课 - 基础物理课程节选