back-up valve
常見例句
- 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(duì)套管閥的設(shè)備配套、理論和應(yīng)用進(jìn)行了較全面的分析研究。
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.
用植絨PVC料經(jīng)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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