vacuum arc真空电弧vacuumn.真空；真空吸尘器；空白adj.产生（利用）真空的v.用吸尘器打扫vacuum solidification真空固化vacuum preconcentrator真空预浓缩器vacuum pressing method真空预压法vacuum-tight housing真空罩vacuum tube multimeter电子管万用表vacuum forming machine真空成型机vacuum contact machine真空接触器vacuum-tube detector真空管检波器vacuum deposited layer真空沉积层vacuum well dewatering真空井点降水