A new conception, average powder density defined as the powder quantity clad on unit area of substrate surface has been put for ward.

提出了粉末分布密度这一新概念，即同步送粉激光熔覆时基体单位面积上分布的覆层粉末质量。

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Mr. Weimer of Phantom Fireworks in Youngstown, Ohio, said that his company believes that the quantity of powder in the fireworks wouldn't have been nearly sufficient to produce the Boston blasts.

WSJ: Boston Bombing Suspects Roused by Jihadist Thought