天然材料改性
natural materials modification
9F级天然气-蒸汽联合循环机组
9F class gas-steam combined cycle unit
复合材料天线框架
the framework of composite antenna
复配天然抗氧化剂
natural antioxidant compound
高级天然色羊毛地毯
natural colour super woollen carpet
航空航天材料
aerospace material
materials of aviation and aerospace
粗骨料级配
gradation of coarse aggregate