parametron
(1)参数器
(2)参数激发子
(3)参变管
(4)参变元

• dual frequency dye laser
• dual-grating spectrography
• dualism
• duality
• dual lattice
• dual lens
• dual mode coding
• dual-polarization
• dual-polarization laser
• dual-polarization oscillation
• dual-polarized ring laser
• dual-seatter laser velocimeter
• dual-trace oscillograph
• duant
• ducon
• duct
• ductility
• ductiny
• dull dullness
• dummy
• dummy load
• dumper
• dumper mirror
• dumping
• dumpy level