Note that the compression ratios shown above reflect the expansion ratio, which is the ratio of the combustion chamber volumes when the piston is at Bottom dead centre and Top dead centre.

请注意，压缩比上述反映膨胀率，这是燃烧室的量的比例时，活塞的下死顶死中心，中心会显示。

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Thin, circular, steel bands fit into grooves around the piston to seal the bottom of the combustion chamber.

把薄的，圆形的，钢圈放进活塞周围的凹槽以密封燃烧室的底部。

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To avoid these two kinds of noise, the paper gived some requirements to the internal structure design of shock absorber, such as piston valve system, bottom valve system, piston rod etc.

为降低或消除这两种减振器噪声，提出了对减振器内部结构如活塞阀系统、底阀系统以及活塞杆等的设计要求。

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Mr. McPheeters's weekend ended early, when he busted a piston on Saturday, sending his snowmobile to the bottom of the lake.

WSJ: Snowmobile Riders Race Over Water on Minnesota Lakes