A hydrogen explosion had also occurred earlier at reactor 2. That brings the number of crippled units to four of the plant's six reactors.

2号反应堆此前也发生过氢气爆炸，这意味着核电站6个反应堆中受损数量升至4个。

youdao

For the crew of a spacecraft ramping up to light speed, interstellar space would appear highly compressed, thereby increasing the number of hydrogen atoms hitting the craft.

对宇宙飞船的船员来说，速度升高到光速，宇宙空间将被高度压缩，因此增加了撞击飞船的氢原子数量。

youdao

Any simple alcohol is composed of a number of carbon and hydrogen atoms (like a hydrocarbon such as petrol) together with a single oxygen atom.

任何一种简单醇类都是有大量的碳分子和氢分子(如同碳氢化合物，譬如汽油)以及单个氧原子组成。

youdao

If you look on the Periodic Table this is 598 atomic hydrogen. And, sure enough, there is 13.598, which is this number here in electron volts.

如果你查找元素周期表上的氢原子,毫无疑问，它的电离能就是13。,这个数值也是电子伏的值。

麻省理工公开课 - 固态化学导论课程节选

So if we're talking about the fourth excited state, and we talk instead about principle quantum numbers, what principle quantum number corresponds to the fourth excited state of a hydrogen atom.

如果我们说的是,第四激发态，我们用,主量子数来描述，哪个主量子数对应了,氢原子的第四激发态？

麻省理工公开课 - 化学原理课程节选

And, that gives you a number for the fluorine, minus 0.29. Now, if you do the same for the hydrogen, you'll come up with the same number.

然后给出F的数字，负的0。29，如果同样的用H来计算，你会得到一样的答案。

麻省理工公开课 - 固态化学导论课程节选

Any simple alcohol is composed of a number of carbon and hydrogen atoms (like a hydrocarbon such as petrol) together with a single oxygen atom.

ECONOMIST: Advanced biofuels

To liberate the hydrogen, Virginia Tech scientists separated a number of enzymes from their native microorganisms to create a customized enzyme cocktail that does not occur in nature.

FORBES: Could Hydrogen Breakthrough Revive The Fuel-Cell Car?

The third selling point: Hydrogen could, in principle, deliver energy independence to every nation because it can be derived using any number of sources-including oil, natural gas, nuclear fission, coal, hydroelectric power and wind.

FORBES: Companies, People, Ideas