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The nucleus contains rope-like strands of DNA that carry the information.
VOA: special.2010.03.23
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And the way that we'll do this is starting with talking about the discovery of the electron and the nucleus here.
在这之后,我们就可以通过,经典力学来描述一个原子。
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We are talking about probability, but what we're saying is that most probable radius is further away from the nucleus.
我们说的是概率，也就是说它的最可能半径,离原子核更远。
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If dark matter particles exist, scientists say, they should be able to observe a small amount of light given off when they hit the nucleus of a xenon atom.
VOA: special.2009.07.21
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We cannot do anything about protons, they are buried in the nucleus, but we can add or subtract electrons.
我们不能改变质子，它们埋藏在原子核内，但是我们能够增加或减少电子。
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"All genes are encoded by DNA and the DNA is present in the chromosomes in the cell nucleus and telomeres, they are the ends of the chromosomes and they have an important function to protect the chromosomes and maintain the integrity of the chromosomes."
VOA: special.2009.10.07
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One of the most obvious things about a red blood cell is it doesn't have nucleus, it has no nucleus.
红细胞最为明显的不同就是,它是无核的,它没有细胞核
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And then the potential energy, the energy is stored here due to the coulombic force of attraction between the electron and the nucleus.
然后说势能,位能其实就是,由电子和原子核之间的库仑引力而形成的能量。
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It was a classical model, right, so we could say the electron is exactly this far away from the nucleus.
这是个经典模型，对吧，我们说电子离,原子核就是这么远。
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So the probability of having an electron at the nucleus in terms of probability per volume is very, very high.
在单位体积内发现,一个电子的概率非常非常大。
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Because what it tells is that we can figure out exactly what the radius of an electron and a nucleus are in a hydrogen atom.
我们可以,准确的算出,氢原子中,电子。
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So I will take into account it that there is some contribution of both the nucleus and the electron.
所以我将考虑,那是原子核与电子,共同作用的结果。
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So, what we're looking at here is the force when we have two charged particles, one positive one negative -- here, the nucleus and an electron.
我们现在研究的是,一正一负俩个带电粒子之间的,作用力-在这里。
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But luckily for us, there's a classical equation of motion that will, in fact, describe how the electron and nucleus change position or change their radius as a function of time.
但幸运的是，有一个,经典方程描述了电子和核子,位置或者它们直接的距离是,如何随时间变化的。
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But what's important is not where that most probable radius is when we're talking about the z effective it feels, what's more important is how close the electron actually can get the nucleus.
但重要的不是,最可能半径,当我们谈论它感到的有效电荷量的时候，更重要的是,电子实际上。
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How far you are away from the nucleus in terms of a radius, they don't depend at all on those two angles, theta they're independent of theta phi and they're independent of phi.
只和离核子的距离，也就是半径有关，它们和,另外两个角度无关，它们不决定于,也不决定于。
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So if you have some charge in the nucleus, but you also have repulsion with another electron, the net attractive charge that a given electron going to feel is actually less than that total charge in the nucleus.
所以如果在原子核中，有一些电荷但是你也有来自，另一个电子的排斥力,那么一个给定电子的,吸引电荷感觉到的事实上,小于原子核中的总电荷。
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So, if I kind of circle where the probability gets somewhat substantial here, you can see we're much closer to the nucleus at the s orbital than we are for the p, then when we are for the d.
我把概率,很大的地方圈出来，你们可以看到在ｓ轨道上,比ｐ轨道更接近原子核，最远是ｄ轨道。
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So if you think of a shell, you can actually just think of an egg shell, that's probably the easiest way to think of it, where the yolk, if you really maybe make it a lot smaller might be the nucleus.
可以把它想成，个蛋壳，这也许是，最简单的思考办法,蛋黄如果，缩小非常多倍的话,就可以想象成核子。
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So what this means is that unlike s orbitals, they don't have the exact same shape at any radius from the nucleus.
这意味着和ｓ轨道不同，它们在离原子核不同距离处的形状不是完全一样的。
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I said what hold the bonds together, what holds two atoms together is the attractive force we have between each electron and the other nucleus.
我说过什么将它们结合在一起，将两个原子结合在一起的是一个吸引力,其中一个原子中的电子与另一个原子中的原子核之间。
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Because we know as we go to infinity, even though the density gets smaller and smaller and smaller, we still have electron density very far away from the nucleus.
因为我们知道即使到了无穷远处，尽管电子密度会变得非常非常非常小，但我们仍然有一定的电子密度，无论离原子核多远。
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Many steroid hormones act because they bind to cellulars - to receptors that are deep within the cell, often inside the nucleus.
许多类固醇激素能够起效是因为,其与存在于细胞内部的受体相结合,这类受体通常在细胞核内
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You can start from one nucleus and go to the next nucleus, and there are no zero planes, no nodes, nothing.
你可以从一个核出发,看向另一个核，中间没有零平面，没有节点，什么也没有。
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And when we do that we can see this curve, this probability curve, where we have a maximum probability of finding the electron this far away from the nucleus.
当我们这样做时，我们可以看到这个曲线，这个概率分布曲线，这里有发现,电子的最大概率。
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If, in fact, a gold nucleus was this size here, we would need to use another lecture hall in order to find a place to put this nucleus right here.
那么这个实验就太诡异了，所以我们决定,把距离压缩一下，我们要考虑到这一点。
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We are expecting to see that it decreases because it's feeling a stronger pull, all the electrons are being pulled in closer to the nucleus, so that atomic size is going to get smaller.
我们将看到它是减小的,因为电子会感受到越来越强的吸引力，所有的电子将会被原子核拉得越来越近，所以原子半径将越来越小。
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We can not do that with quantum mechanics, the more true picture is the best we can get to is talk about what the probability is of finding the electron at any given nucleus.
在量子力学里我们不这样做，我们能得到的更加真实的图像,是关于在某处,找到电子的概率。
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And the reason that they're the least sheilded is because they can get closest to the nucleus, so we can think of them as not getting blocked by a bunch of other electron, because there's some probability that they can actually work their way all the way in to the nucleus.
它们最不容易被屏蔽的原因,是因为他们可以更加接近原子，所以我们可以认为它们,最不容易被其它原子阻挡住，因为它们有一定的概率,离原子核非常近。
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So, what you see is near the nucleus, the density is the strongest, the dots are closest together.
你看在核子附近，密度非常高，这些点非常密。
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