billion
(1)千兆，十亿，109(美、法)
(2)兆兆，万亿，1012(英，德)

• ultrasound holography
• ultrathing microscope
• ultrathin laser
• ultra trace
• ultraviolet
• ultraviolet absorbing filters
• ultraviolet absorption spectrometry
• ultraviolet and visible spectrophotometer
• ultraviolet astronomical photometry
• ultraviolet band
• ultraviolet bandpass filter
• ultraviolet catastrophe
• ultraviolet curing equipment
• ultraviolet cutoff
• ultraviolet detection
• ultraviolet dosimeter
• ultraviolet-emitting source
• ultraviolet impulse optics
• ultraviolet-induced
• ultraviolet injury
• ultraviolet lamp
• ultraviolet laser
• ultraviolet lenses
• ultraviolet light
• ultraviolet light sources