球形字頭 的英文怎麼說
中文拼音 [qiúxíngzìtóu]
球形字頭
英文
small metal sphere with raised letters on it used in some electric typewriters-
Because of the lower rock fragmentation efficiency and defective geometrical shape of chisel bit, sweden has replaced chisel bit with taper connecting cross chisel bit and button bit since the mid - seventies
因一字形釬頭破巖效率低和幾何形狀結構缺陷等問題,瑞典從70年代中期就用錐體連接的十字和球齒釬頭取代了一字形釬頭。
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