| D007854 |
Lead |
A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.2, symbol Pb. |
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| D002849 |
Chromatography, Gas |
Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix. |
Chromatography, Gas-Liquid,Gas Chromatography,Chromatographies, Gas,Chromatographies, Gas-Liquid,Chromatography, Gas Liquid,Gas Chromatographies,Gas-Liquid Chromatographies,Gas-Liquid Chromatography |
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| D005740 |
Gases |
The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed) |
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| D000397 |
Air Pollution |
The presence of contaminants or pollutant substances in the air (AIR POLLUTANTS) that interfere with human health or welfare, or produce other harmful environmental effects. The substances may include GASES; PARTICULATE MATTER; or volatile ORGANIC CHEMICALS. |
Air Quality,Air Pollutions,Pollution, Air |
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| D012494 |
Sampling Studies |
Studies in which a number of subjects are selected from all subjects in a defined population. Conclusions based on sample results may be attributed only to the population sampled. |
Probability Sample,Probability Samples,Sample, Probability,Samples, Probability,Sampling Study,Studies, Sampling,Study, Sampling |
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