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

• double helical gear
• double helical tooth
• double-heterostructure
• double-heterostructure injection laser
• double-humped
• double-humped wave
• double image
• double image micrometer
• double image ocular
• double image prism
• double image range finder
• double integral
• double layer
• double lens magnifier
• doublem\-beam spectrophotometer
• double mirror
• double-pass monochromator
• double pass planar dye laser amplifier
• double-pass spectrometer
• double-pivoted type
• double prism field glass
• double protractor
• double-pulsed flash lamp
• double-pulsed time
• double pulse excitation