In a gas mask designed to guard against a biological threat, a very fine particulate filter is useful.

预防生物威胁时，优良的微粒过滤器对防毒面具非常有用。

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It contains a fine filter to exclude particles of dust or dirt which may have found their way into the tank.

它包括一个细滤器，用来滤除可能混入油箱中的灰尘或脏物。

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Ro - reverse osmosis pretreatment process for activated carbon and fine filter.

反渗透预处理工艺主要为活性炭和精滤。

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In humans the vocal tract acts as a filter on the sound from the source, and the "source-filter theory" held that the separate, fine control of the vocal tract to be the product of a long evolution in the development of the subtleties of speech.

BBC: Helium-huffing gibbons 'sing with soprano technique'