radiant flux [surface] density
辐[射]通量[面]密度

• final reading
• final stage
• final vacuum
• final value theorem
• finder
• finder aperture
• finder circle
• finder frame
• finder screen
• finder telescope
• fine
• fine adjustment
• fine balance
• fine-collimation apparatus
• fine data channel
• fine definition
• fine detail
• fine dotted line
• fine etching
• fine-focusing knob
• fine grain
• fine grain developer
• fine-grained
• fine grating
• fine grinding wheel