n.喘氣者;廉價香煙
Gas Drainage Technology with Upward Hole Installed Gasper Casing Pipe in Dynamic Pressure District of Sublevel Caving Faces 放頂煤工作面仰斜鉆孔安設(shè)透氣套管抽放動壓區(qū)瓦斯
gasper air ventilation 乘客個人通風(fēng)裝置