And alpha is something that we can measure at distant places in the universe and thereby back in time by looking at these atomic spectral lines.

我们可以在宇宙里遥远的地方测量阿尔法常数，从而通过研究这些原子光谱线回到过去。

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Physicists have no trouble using, on the one hand, picoseconds (trillionths of a second) or even femtoseconds (quadrillionths of a second) to discuss time at the atomic scale.

在讨论原子级别时间的时候，物理学家用起皮秒（百万兆分之一秒）甚至飞秒（千万亿分之一秒）来都没任何不便。 这是一方面。

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At the US Naval Observatory in Washington, its newest atomic clock is getting a climate-controlled room of its own for the first time.

在位于华盛顿的美国海军天文台，这里最新的原子钟首次得到了一个拥有空调的专用房间。

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At the same time, Mister Oppenheimer became chairman of the advisory committee to the United States Atomic Energy Commission.

VOA: special.2009.06.14

For example, in terms of the atomic theory of matter, at the time at the turn of the Century, the understanding was that atoms were the most basic constituent of matter, meaning you couldn't break atoms up into anything smaller - that was it, you're done.

例如在原子理论中,在19，20世纪之交的时候,人们认为原子是,组成物质的最基本粒子,也就是说你不能,把原子再分割了,就这样了。

麻省理工公开课 - 化学原理课程节选

Jerrold Zacharias at the Massachusetts Institute of Technology developed a practical atomic clock around the same time that Louis Essen and John Parry established the first atomic clock at the National Physical Laboratory in Teddington, west of London.

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Iraq maintains that it no longer has any such programmes, although one senior Iraqi official has all but admitted that the country came close to building an atomic bomb in 1991, at the time of the Gulf war.

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Tokyo radiation levels are not hazardous to human health at this time following radiation leaks at the Fukushima nuclear power plant, the International Atomic Energy Chief Yukiya Amano told reporters Wednesday.

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