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AIDS researchers say they still have much work to do on a vaccine against H.I.V.
VOA: special.2009.09.30
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It turns out after you do all the math, H it turns out to be delta H equals zero.
要等你做完所有的计算之后，才能知道结果，结果证明Δ
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H And, by the way, if you do this for the hydrogen, H it ought to come out the same.
顺便说一句，如果是，或者如果是。
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When we increase the potential between the 2 electrodes that we have in the tube -- we actually split the h 2 into the individual hydrogen atoms, and not only do that, but also excite the atoms.
当我们增大两个电极之间电压,我们有-我们可以把氢气2,分解成单个的氢原子，不仅这样，还能激发原子。
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How do we go from that experiment to H the terms that we're trying to get, these slopes.
我们怎样从实验得到我们想要的量？,记住，我们想要得到Δ
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I want to then do, I need to find the square root b squared plus h squared, right?
我接下来要求b的平方和h的平方,的和的平方根对不对？
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But how do we get to 1861 and that secession crisis with Alexander H. Stephens delivering this Cornerstone Speech, declaring that, "Hey folks, it's all about slavery and its preservation?"
但事情怎么会演变到1861年那样,乃至之后的分离危机,亚历山大为何能在这篇演讲中,宣称,"嘿,伙计们,今天我要讲的是奴隶制和对其保护"
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So, the first thing we do is put two electrons between h and c, and then two electrons between c and n.
那么，我们先在氢和碳之间放两个电子，然后在碳和氮之间再放两个电子。
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H- *H + e-> H-* And, clearly, we can't do both.
到一个电子生成*,但我们发现我们不能同时做到两个。
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Do we calculate, you know, delta S, delta u, delta H?
是否要计算熵的变化，内能的变化，自由焓的变化？
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And so we can actually think about how do we calculate what the dissociation energy should be for h 2, so let's go ahead and do this.
因此，我们其实可以想到应该如何计算,氢分子的离解能，那么我们开始做一下吧。
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So it helps us predict, will we see this, for example, h 2, which we're going to be about to do, we'll see is stabilized because it has more bonding than anti-bonding.
这帮助我们预测，我们等会会看到，比如H2O，我们等会要讲到，我们会看到它更稳定是,因为成键比反键更多。
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And the last thing we can think about is how do we name this n h bond, and again, we just name it based on it symmetry.
最后我们要讨论的是,如何命名这个NH键，同样，我们基于它的对称性命名它。
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All right, so now let's see how we execute it, and do the calculations that allow us to calculate this. So, one, what's delta H in step one?
好，现在我们看看怎样操作它，怎样进行计算，第一步,步骤I的ΔH是多少？
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So we know that we can relate to z effective to the actual energy level of each of those orbitals, and we can do that using this equation here where it's negative z effective squared r h over n squared, we're going to see that again and again.
我们知道我们可以将有效电荷量与,每个轨道的实际能级联系起来，我们可以使用方程去解它,乘以RH除以n的平方,它等于负的有效电荷量的平方,我们将会一次又一次的看到它。
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And I picked looking at methane so we could see if there are other factors that we're not considering, that we need to maybe tweak our model a little bit, and I think we'll find that we do if we take a look at a polyatomic molecule, methane, CH4 so c h 4.
我选择甲烷这个例子，我们可以看到,如果有一些我们没有考虑到的因素，我们需要修改一下我们的模型，我们看一看,甲烷CH4这个多原子分子，就会知道这一点，甲烷。
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