单项选择题
A.70% B.85% C.90% D.100%
A.标准孔板 B.标准喷嘴 C.文丘里管 D.1/4圆喷嘴
A.径距为50~750mm内,孔板比β为0.22~0.80 B.径距50~750mm内,孔板比β为0.10~0.75 C.径距50~1000mm内,孔板比β为0.22~0.80 D.径距50~1000mm内,孔板比β为0.10~0.75