An in-service valve suffering from Dezincification has a white powdery substance or mineral stains on its exterior surface.

使用中的阀门如果遭遇脱锌侵蚀，会在阀门外表产生白色粉末或矿物污点。

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A letter containing a powdery substance is believed to be the source of the anthrax becteria that showed up as a skin rash on an NBC employee.

一封带有粉状物质的信件被确定为炭疽热细菌的来源，因为一位NBC雇员已经由此得了皮炎。

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The physical attributes of an in-service valve with Dezincification includes a white powdery substance or mineral stains on its exterior surface.

使用中的阀门出现失锌想象时的物理特征包括：在外表面出现白色粉末或矿物污点。

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The letter contained a "threatening note and powdery substance, " said Lieutenant Dan Nichols, a spokesman for the Capitol Police.

BBC: Senate employees on Capitol Hill

On September 25, the woman had contact with a letter or package with a white powdery substance and began experiencing symptoms of cutaneous anthrax three days later.

CNN: Cutaneous anthrax most common, most survived

The powdery lignin, once separated from the cellulose, is a very useful substance in its own right.

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