Fully enclosed, no seams, no cavity, no hot and cold bridge.

全封闭、无接缝、无空腔，没有冷热桥产生。

youdao

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。

youdao

Benign tumors, soft tissue shadow with no clear bone destruction, but often with enlarged sinus cavity.

良肿瘤有腔内软组织影，但骨破坏不明显，亦常有窦腔扩大。

youdao

An attempt to make contact with the trapped miners was unsuccessful Friday, when a microphone lowered into a narrow hole drilled into a mine cavity detected no sounds.

CNN: Camera lowered into mine cavity shows 'survivable space'

"By that I mean try to imagine creating a cavity inside your mouth without any air bubbles and by letting in no air through your lips or throat -- it's basically impossible at sea level because the air pressure outside your mouth pushes the air pocket closed, " he said.

CNN: Training for civilian space travel is no picnic, Garriott says