dual map对偶图dualadj.双重的；成双的n.双数dual explosive charge双元炸药装药dual ball check valve双球止逆阀dual-bore drill rod双孔钻杆Dual-level priority双优先级dual-purpose column两用柱dual governance model双重治理模式Dual-mode resonator双模谐振器Dual-Buck converter双Buck变换dual-primary system双主用系统dual-purpose cattle乳肉兼用牛