A、鋁 B、鐵 C、銅 D、鋅
A、制造的缺陷 B、換熱銅管腐蝕出現(xiàn)裂紋、穿孔和破損 C、凝汽器管子和管板的固接不良 D、固接處嚴(yán)密性遭到破壞
A、樹(shù)脂呈淺綠色為陽(yáng)樹(shù)脂,樹(shù)脂不變色為陰樹(shù)脂 B、樹(shù)脂呈淺綠色為陰樹(shù)脂,樹(shù)脂不變色為陽(yáng)樹(shù)脂 C、樹(shù)脂呈淺綠色為陽(yáng)樹(shù)脂,樹(shù)脂深綠為陰樹(shù)脂 D、樹(shù)脂呈深綠為陽(yáng)樹(shù)脂,樹(shù)脂淺綠為陰樹(shù)脂