A.0.3±0.04 B.0.25±0.03 C.0.36±0.04 D.0.45±0.04
A.YBJ-35 B.YPB-10 C.YPB-30 D.YBJ-10
A.s=0.04d2 B.s=0.785d2 C.s=4×0.315d2 D.s=0.215d2