Some of their work involved X-rays produced by particle accelerators, devices that bring atomic particles into high energies.

VOA: special.2009.12.08

I will draw the famous picture of some particle moving and it's here at t of some value of x.

我会画某个质点运动的,经典图像,这是某个x值对应的时间t

耶鲁公开课 - 基础物理课程节选

You're only given the particle has acceleration a, and you are asked to find out what is x?

你只知道质点的加速度为a,你需要求出x是多少

耶鲁公开课 - 基础物理课程节选

There is no way that you could irradiate a crystal of nickel with a single beam of x-rays and get that circular ring pattern if the electron beam were behaving as a particle beam only.

没有什么其他的途径,可以让镍晶体发射,单束X光来,继而得到环状图案,如果电子束,是以粒子束形式出现的。

麻省理工公开课 - 固态化学导论课程节选

Then, I gave you one other very important example of a particle moving in the x-y plane.

下面我再拿一个重要的例子,质点在 x-y 平面内的运动

耶鲁公开课 - 基础物理课程节选

So what I've said so far is, a particle moving in time from point to point can be represented by a graph, x versus t.

到目前为止,我说过,一个质点随时间的连续运动,可以用一幅x-t图来表示

耶鲁公开课 - 基础物理课程节选

Our picture now is going to be some particle that's traveling in the x-y plane.

我们现在的情景是在 x-y 平面内,运动的质点

耶鲁公开课 - 基础物理课程节选

We said, "Let's take, for the simplest case that we can possibly imagine, namely a particle moving in one dimension along the x-axis with a constant acceleration a.

我们说过,"考虑我们可以想象的最简单的情况,即质点在一维空间运动,沿着 x 轴且保持恒定加速度 a

耶鲁公开课 - 基础物理课程节选

And that's the following. Let's take a particle that is moving in the x-y plane, so that at one instance-- sorry, let me change this graph-- is here--oh, this is bad.

接下来,我们来看一个物体,在 x-y 平面内运动,在这个例子中,对不起,我要重画一下这个图,在这里,这画得不好

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For example, suppose you use vertical motion and you use y instead of x; and a would be g or -g; that's a particle falling down under the affect of gravity.

例如,假设在竖直运动中,你用 y 来代替 x,那么 a 就是 g 或者 -g,这就是一个受重力作用下落的质点

耶鲁公开课 - 基础物理课程节选

So, the question we are going to ask is the following, "If I tell you that a particle has a constant acceleration a, can you tell me what the position x is?"

接下来要问的问题就是,如果我说某质点加速度恒为a,你能告诉我它的位移x是多少吗

耶鲁公开课 - 基础物理课程节选

If you are describing a particle with location R, the vector we use typically to locate a particle, R then R is just i times x + j times y, because you all know that's x and that's y.

如果你要描述一个位移为 R 的质点,这个矢量一般用表示质点 R 的位移,R 可表示为 i ? x + j ? y,显然你们都知道这段是 x,那段是 y

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