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We turned another corner around the central plaza area and the density of people is even greater over here.
VOA: standard.2010.01.14
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So, one way we could look at it is by looking at this density dot diagram, where the density of the dots correlates to the probability density.
其中一个理解它的方法,就是通过看这个密度点图，这里点的密度,和概率密度想关联的。
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So we can see if we look at the probability density plot, we can see there's a place where the probability density of is actually going to be zero.
就能看到,有些地方，找到一个电子的,概率密度,我们可以考虑。
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The study is said to be the first to examine in detail measurements of bone strength instead of bone density.
VOA: special.2009.03.10
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And then he says the tetrachloride will be volatile, 9 and it will have a density of 1.9.
他说四氯化物具有不稳定性，密度是1。
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This mixing is a product of the oceans' density and buoyancy.
VOA: special.2011.06.22
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You make the volume infinitely large, the density of the gas infinitely small.
密度无限小，气体分子之间的相互作用。
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How is anyone going to give you a density of anything?
你怎样获得任意物体的密度
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You've probably seen agar plates, if you smear a solution that's contaminated with bacteria on it, then that bacteria will grow on this agar rich medium and you'll get many, many copies of the bacteria that you've smeared at low density onto the plate.
你们大概见过琼脂培养基,如果将有细菌的溶液涂抹在培养基上,细菌就会在富含琼脂的培养基上生长,你会得到许多许多细菌,即使你只涂抹了低浓度溶液
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So the fact is those lab animals have a hard-wired preference for foods that are high in fat and high in sugar, primarily because of the energy density that those foods bring to one, and then the variety is important because you get a mix of nutrients.
事实上 实验动物对高脂肪高糖的食物,有着强烈的偏爱,而这种爱基于,该类食物能给我们提供高能量,多样性很重要,因为你能摄取多种营养
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And when we take the wave function and square it, that's going to be equal to the probability density of finding an electron at some point in your atom.
当我们把波函数平方时，就等于在某处,找到一个电子的概率密度。
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Probability density of finding an electron within that molecule in some given volume.
在分子内某空间找到,一个电子的概率密度。
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And he predicts the density of the oxide of the yet undiscovered element.
他预测这个还未被发现的元素的,氧化物的密度。
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So, this is about a quarter of the density of steel.
所以镁的密度是贴的四分之一。
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So, again we can use these probability density plots, which are just a plot of psi squared, where the density of the dots is proportional to the density, the probability density, at that point.
同样的我们可以利用这些概率密度图，这是psi的平方的图，这里面点的密度，正比于概率密度。
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It's one of the only compounds, there's only I think three, where the density actually goes down when it freezes.
它是我见过的，唯一一个，在降温时密度下降的化合物。
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So you can think about how these 2 things combined are going to be electronegativity, which is a measure of how much an atom wants to pull electron density away from another atom.
因此你可以想象出,这两样性质合起来就是电负性，也就是一个度量，关于一个原子,有多希望把另一个原子的电子密度拉过来的。
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Think of anything else with the density goes down when it freezes, and think about where we would be if that wasn't the case.
想想有没有其他的物质,在降温时密度会变大，再想想如果不是这种情况,我们将会怎么样。
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So again if we look at this in terms of its physical interpretation or probability density, what we need to do is square the wave function.
如果我们从物理意义或者,概率密度的角度来看这个问题，我们需要把波函数平方。
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So it's just a measure of how much does one given atom want to pull away electron density from, let's say, an adjacent atom.
因此，它就是度量一个给定原子有多么,想把电子密度拉过来，可以说，从相邻的一个原子那里。
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So again, we can think about the probability density in terms of squaring the wave function.
同样的，我们可以把,波函数平方考虑概率密度。
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So, what we're going to define is just let's just capture 90% of that electron density.
所以，我们所定义的,只包括百分之九十的电子密度。
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So, the quantum mechanical interpretation is that we can, in fact, have probability density here and probability density there, without having any probability of having the electron in the space between.
量子力学给出的解释是，实际上，我们可以在这有概率密度，在这里有概率密度,但在两个之间没有。
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This should make sense because if something has a low ionization energy, that means it's not very electronegative, which means it's going to be a lot happier giving up electron density, which is essentially what you're doing -- when you're forming covalent bonds is you're sharing some of your electron density.
这应该是合理的,因为如果某物的电离能很低，这也就意味着它的电负性也不高，那么它就会更愿意,放弃一定的电子密度，而本质上这正是你在,形成共价键时所需要做的,分享你的一些电子密度。
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Think of it as a probability density plot.
把它看成是一个概率密度图。
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So, what we can do to actually get a probability instead of a probability density that we're talking about is to take the wave function squared, which we know is probability density, and multiply it by the volume of that very, very thin spherical shell that we're talking about at distance r.
我们能得到一个概率,而不是概率密度的方法,就是取波函数的平方，也就是概率密度，然后把它乘以一个在ｒ处的,非常非常小的,壳层体积。
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So, for example, we have this average level, and then it can go high where we have the peak, or it can go very low. We can also discuss sound waves, so again it's just the periodic variation of some property -- in this case we're talking about density, so we have high density areas and low density areas.
例如这是平均位置，在峰的位置水位高，在谷水位低，我们也可以,讨论声波它也是某种,量的周期变化，在这里我们,讨论的是密度,我们有高密度区和低密度区。
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6 It's got a density of about 1.76 at room temperature.
在室温下密度是1。
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We can graph out what this is where we're graphing the radial probability density as a function of the radius.
我们可以，画出它来,这是径向概率密度,作为半径的一个函数图。
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So for example, that might have a formal charge of negative 1, because to some extent it has gained that much electron density that it now has a formal charge that's negative.
比如，可能它的形式电荷为负一，因为在一定程度上它得到了这么多的共用电子密度,那么它现在就有了负的形式电荷。
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