The increase of the cavity volume makes partial materials realize the air impact, the unbroken parts of which enter into the grinding zone and become fine powder after many times of impact.

容积腔增大，使部分物料实现了空中打击，其未破碎部分经过多次打击后进入研磨区形成细粉。

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They are the cavity radiometer and the water flow power meter for laser power measurement, the cone calorimeter and the volume-absorbing calorimeter for laser energy measurement.

有测量激光功率的空腔型辐射计和流水式功率计、测量激光能量的锥型能量计和体吸收型能量计。

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As the joint surfaces suddenly separate, there is no more fluid available to fill the increasing joint volume, so a cavity is formed and that event is what is associated with the sound.

当关节接合处突然分开，液体无法流入不断增大的关节真空处，因此形成了一个气泡，这就是响声的来源。

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