Nirogen ( forms ) about four fifths of the atmosphere 氮气占大气层组成部分的五分之四
2.
Simple unfired pressure vessels designed to contain air or nirogen . part 4 : aluminium alloy pressure vessels designed for air braking equipment and auxiliary penumatic equipment for railway rolling stock 设计用于装空气或氮气的不用火加热的一般压力容器.第4部分:用于铁路运输车辆空气制动设备和辐助气动设备的铝合金压力容器