vacuum preloading

例句：

1. 1. The vacuumpreloading system is designed to improve theefficiency of the pumping process.
   真空预加载系统旨在提高泵送过程的效率。
2. 2. Duringthe vacuum preloading stage, the airin the chamber is removed and replaced witha gas mixture.
   在真空预加载阶段，腔体内的空气被移除并用气体混合物替换。
3. 3. The vacuum preloading technique has beenshown to significantly reduce the time required forthe assembly process.
   真空预加载技术已被证明可以显著减少组装过程所需的时间。