The Dow Jones Industrial Average closed down five points today end at session of 15,440.

今天，道琼斯工业平均指数下跌5点，报收15,440点。

Finally, we explained why a pipe with one closed end can’t have even-numbered harmonics.

最后， 我们解释了为什么一端封闭的管道不能有偶数次谐波。

But a pipe with one closed end and one open end works a little differently.

但长笛一端封闭另一端敞开 它以不同的方式工作。

First, the closed end of the pipe will be a node, because the air molecules aren't oscillating there.

首先，双簧管的封闭端将是一个结，因为 空气分子不会在那里振荡。

Finally, we explained why a pipe with one closed end can't have even-numbered harmonics.

最后，我们解释了为什么长笛不带尖头的声音 闭合双谐波。

But because of the physics of standing waves, instruments that have pipes with one closed end won't create the even-numbered harmonics at all.

但是由于驻波的物理特性，具有一端封闭管道的乐器根本不会产生偶数谐波。

The same thing holds true for air in a pipe: a closed end will invert the wave, while an open end won't.

与开放端不同，封闭端反射波浪。

The same thing holds true for air in a pipe: a closed end will invert the wave, while an open end won’t.

管道中的空气也是如此：封闭端会反转波浪， 而开口端不会。

And between those peaks, as well as at any closed ends of the pipe, are areas where molecules don't move at all; those are the nodes.

在那些峰顶和声门的任何封闭端之间， 分子不移动的区域是节点。

And between those peaks, as well as at any closed ends of the pipe, are areas where molecules don’t move at all; those are the nodes.

在这些峰之间， 以及管道的任何封闭端， 都是分子根本不移动的区域； 这些是节点。

Before the end of 2022, the MTA will have to decide whether it wants to continue with the open gangway designs, or go back to closed ended trains.

在 2022 年底之前，MTA 将不得不决定是继续采用开放式舷梯设计，还是回到封闭式列车。

We discussed harmonics, and how to find the frequency of a standing wave on a string with two fixed ends, a pipe with two open ends, and a pipe with one closed end.

我们讨论了谐波，以及如何找到两端固定的弦、两端开口的管子和封闭端的管子上的驻波频率。

Here, standing waves need a separate set of equations, for a couple of reasons: First, the closed end of the pipe will be a node, because the air molecules aren’t oscillating there.

在这里，驻波需要一组单独的方程式， 原因如下：首先，管道的封闭端将是一个节点， 因为空气分子不会在那里振荡。

The doors of the house, wide open from dawn until bedtime, were closed during siesta time under the pretext that the sun heated up the bedrooms and in the end they were closed for good.

房子的门从黎明一直开到睡觉，在午睡时间关闭， 借口是太阳晒热了卧室， 最后它们永远关闭了。