back-up valve
常见例句
- Furtherly, the paper also takes the back-up equipment, concept and application for the downhole-deploymemt-valve into full research.
此外，本文還對套琯閥的設備配套、理論和應用進行了較全麪的分析研究。
lib.swpu.edu.cn - PVC flocking materials used by high-frequency hot press molding, gas valve back up, with both gas permeability and gas leak-proof function.
用植羢PVC料經高頻熱壓成型，倒閥門氣嘴，具有雙層防漏氣滲氣功能。
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