We look at soil chemistry—for example, how much nitrogen or magnesium there is in the soil in one spot—and we compare it with the chemistry of the soil a short distance away.

我们会观察土壤的化学性质——比如某个地方的土壤里有多少氮或者镁——然后与附近土壤的化学性质作比较。

youdao

The use of nitrogen will depend on the solder paste flux chemistry.

是否使用氮气取决于焊锡膏焊剂的化学特性。

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There are many ways such as physics, chemistry, ion exchange, man-made wet land and biology etc. wastewater nitrogen removal. The biological way is used widely now.

近年来污水脱氮主要有以下几种基本方法：物理法、化学法、离子交换法、人工湿地法及生物法，生物法是目前应用最广泛的方法。

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Over the 140 years of the new time series, this nitrogen component of river chemistry is seen to climb relentlessly.

BBC: Thames archive reveals long nitrate rise

Bacteria evolved the necessary chemistry to "fix" nitrogen from the air, about two billion years ago.

BBC: Leaving our mark: Fossils of the future

The fact that people have used industrial chemistry to short-circuit the nitrogen cycle, by making fertilisers out of nitrogen in the air at a rate which greatly exceeds what natural systems can manage, has real environmental effects.

ECONOMIST: The global environment