fixed distance double line

parallel double suspender

1000 kV insulator string

500kV rod composite string insulator

insulator string

parallel attack＝ parallel method＝parallel fire suppression

double blind double dummy

Double blind double dummy randomized controlled clinical trial

Double Chambers and Double Layers

Double chambers double layers floating bed

Double columns and double FIDs

Double frequency pulsation double vertical ring high gradient magnetic separator

double lift double cylinder jacquard

double -peak double -wavelength method

double pole double throw

double side double arc welding

double stack two-valve double outlet hydrant

double stem and double layer

double tube double swivel barrel

double tube double tube-plate heat exchanger