A.18°~22° B.15°~18° C.22°~25°
A.A=K(1/d-1/D) B.A=K(lg1/d-lg1/D) C.A=K(d-1/2-D-1/2)
A.均勻性系數(shù) B.特征粒徑 C.比例系數(shù)