In August,American Secretary of State Hillary Clinton promised more than seventeen million dollars to fight sexual violence in the D.R.C.

VOA: special.2009.10.24

You can take a derivative of the derivative and you can get the acceleration vector, will be d^2r over dt^2, and you can also write it as dv over dt.

你可以对导数再求一次导,你就可以得到加速度矢量,也就是 d^2 r / dt^2,你也可以写成 dv / dt

耶鲁公开课 - 基础物理课程节选

The most important result from last time was that if you took this r, and you took two derivatives of this to find the acceleration, d^2 r over dt^2, try to do this in your head.

上节课最重要的结论,就是如果你把 r 写成这样,对 r 求两次导就能得到加速度,d^2 r / dt^2,心算一下

耶鲁公开课 - 基础物理课程节选

The American Food and Drug Administration says R.F.I.D.tags act like an electronic safety net to make it easier to catch counterfeits.

VOA: special.2010.03.01

So if we want to talk about the volume of that, we just talk about the surface area, which is 4 pi r squared, and we multiply that by the thickness d r.

如果我们要讨论它的体积，我们要用的是表面面积，也就是４πｒ的平方，乘以厚度ｄｒ

麻省理工公开课 - 化学原理课程节选

We talked with Jamaica Corker, on her cell phone, at the Population Services International office in the D.R.C.

VOA: special.2010.05.03

There was a huge old insurrection called the Fronde, f-r-o-n-d-e.

有一起被称为投石党运动的起义

耶鲁公开课 - 欧洲文明课程节选

A list of American colleges and universities that offer financial aid to foreign students can be found at edupass.org -- e-d-u-p-a-s-s dot o-r-g.

VOA: special.2009.02.05

We're saying the probability of from the nucleus in some very thin shell that we describe by d r.

某一非常薄的壳层dr内,一个原子的概率,你想一个壳层时。

麻省理工公开课 - 化学原理课程节选

The D.A.R. would not permit Anderson to perform in the concert hall because she was black.

VOA: special.2009.01.25

r And what that is the probability of finding an electron in some shell where we define the thickness as d r, some distance, r, from the nucleus.

在某个位置为,厚度为dr的壳层内,找到原子,的概率，我们来考虑下我们这里所说的。

麻省理工公开课 - 化学原理课程节选

And this one, I was skiing out in Salt Lake City and the name of a building out there was Reid with R-E-I-D and it sounded good at the time."

VOA: special.2009.07.06

a perfectly spherical shell dr at some distance, thickness, d r, dr we talk about it as 4 pi r squared d r, so we just multiply that by the probability density.

在某个地方的完美球型壳层,厚度，我们把它叫做4πr平方，我们仅仅是把它,乘以概率密度。

麻省理工公开课 - 化学原理课程节选

Additional Home Secretary D.R.S.Chaudhary told a news conference Sunday authorities and citizens need to be vigilant, especially in five eastern states.

VOA: standard.2009.06.21

So, we can do that by using this equation, which is for s orbitals is going to be equal to dr 4 pi r squared times the wave function squared, d r.

用这个方程,对于s轨道，径向概率分布,4πr的平方,乘以波函数的平方,这很容易理解。

麻省理工公开课 - 化学原理课程节选

"And,the President's budget for 2009 in the recovery act had the largest increase for R&D that we have seen in recent years."

VOA: standard.2009.08.31