He says they actually use dental floss to slowly saw away at the metal, adding tooth powder to increase the friction.

但是犯人们总能找到办法弄到。现在他们用牙线慢慢钜金属，抹上牙粉增加摩擦力。

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The friction factor between two tooth surfaces of instrument gears during one meshing process is imitatively measured in this paper under the condition of ultra-low-speed.

本文在极低速情况下，模拟测定了仪表齿轮在一齿啮合过程中两齿轮齿面间摩擦系数的变化情况。

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As one of these components, friction modifier plays an important function for removing the dirt and colored substance attached to the surface of tooth.

磨擦剂作为牙膏的组分之一，在其中起着重要的作用，它能有效的除去附着在牙齿表面的污垢和有色物质。

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