A part that operates by sliding, as the U-shaped section of tube on a trombone that is moved to produce various tones.

型滑管：靠滑动操作的部分，如长号上u型的管子部分，拉动它可以产生各种声调。

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The results show that the local heat transfer at the front part of the drop-shaped tube is similar to round tube, but apparent difference appears behind the detachment point.

结果表明：滴形管束局部换热规律在前端大圆部分与圆管管束相似，但在脱体点以后差别较大；

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Though the Astor's bolsters stand alone, most designers still use the tube-shaped cushions as part of a pillow mix.

WSJ: Bolster Cushions Win Best Supporting Rolls