refracting power
(1)折射率
(2)折射本领，折光能力

• sight vane alidade
• sigmoidoscope
• sign
• signal
• signal averager
• signal beam
• signal-carrying laser beam
• signal conversion
• signal distortion noise
• signal entropy
• signal flow
• signal-generating image tube
• signal generator
• signaling
• signal-integrating
• signal intensity
• signal lamp
• signal level
• signal light
• signal marker light
• signal plate
• signal processing
• signal-to-background ratio
• signal-to-noise ratio
• signal transition