A.B/2hg≤φB.B/2hg>φC.B/hg>φD.b/2hg=φ
A.磨料磨損B.機(jī)械磨損C.腐蝕磨損D.化學(xué)磨損
A.抗磨作用B.清潔分散作用C.助燃作用D.降低了燃油表面張力