The likely source is not atmospheric pollutants, but lab accidents.
其污染源不是空气污染物,而属于实验室偶然事件。
Say you drop a thermometer and it shatters, he says.
比如你把一个温度计丢掉地面上,里面的水银散开了,坎普森博士说,
A couple of blobs of mercury fall through the floorboards and evaporate slowly over theyears. Some of that mercury is then deposited.
几滴水银落在地板上,随着时间,慢慢蒸发在空气中,其中一些会沉积。
Unlike the atmospheric junk, which simply encrusts the surface, mercury seeps intomicroscopic flaws in the cylinders surfaces created by the polishing process.
和仅仅落在圆柱表面的空气污染物不同,水银会渗进圆柱体在擦磨过程中表面留下的微小缺陷里。
Once it gets in, it s in there for good. You can t remove it, says Dr Cumpson.
只要水银渗进去了,它就会永远留在圆柱体里了。你根本无法去除,坎普森博士说。
The missing Planck
被人遗忘的普朗克
It is problems like thisand the fact that the world s kilograms are changing in mass atdifferent ratesthat are behind a push to bring the kilogram into line with the rest of the SI,and to define it purely with reference to natural constants.
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