coincidence rangefinder
重合测距仪

• duant
• ducon
• duct
• ductility
• ductiny
• dull dullness
• dummy
• dummy load
• dumper
• dumper mirror
• dumping
• dumpy level
• duo-binary system
• duodeno-fiberscope
• duodiode
• duojdecimal
• duolaser
• duple
• duplex
• duplicate
• duplicate test
• duplicating film
• duplication
• durability
• duralumin