By subjecting a tungsten core wire in the electro deposit solution containing {HEAD ~ the ternary carbonate} of {TAIL ~ 2.0 μm particles} to cataphoresis, filament cathodes on each of which an oxide is coated in a thickness of 0.5, 1, 2, 3, 4, 5, 6, 7, or 8 μm are fabricated 
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By subjecting a tungsten core wire in the electro deposit solution containing { HEAD ~ the ternary carbonate } of { TAIL ~ 2.0 μm particles } to cataphoresis , filament cathodes on each of which an oxide is coated in a thickness of 0.5 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , or 8 μm are fabricated
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH