refractive null corrector
折射零值校正器

• physiological photometer
• physiology
• physioptial
• physi-optics
• pic
• pickoff
• pickoff couple
• pick-off diode
• pick-off gear
• pickoff unit
• pick-up
• pick-up camera
• pick-up head lenses
• pick-up system
• pick-up tube
• piclear unit
• picling
• picnometer
• pico
• picosecond
• picosecond light pulse
• picosecond pulse
• pictorial display
• pictorial holography
• pictorial infrared photography