{TAIL ~ The projection} of electron beams that are transmitted by the slot apertures and strike the fluorescent screen can be made straight by boring slot apertures in {HEAD ~ advance} that are curved in the direction opposite the curvature of the electron beam projection 
{ TAIL ~ The projection } of electron beams that are transmitted by the slot apertures and strike the fluorescent screen can be made straight by boring slot apertures in { HEAD ~ advance } that are curved in the direction opposite the curvature of the electron beam projection
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