电机和变压器铁芯采用的铁磁材料为（   ）。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69398' and id < 4492758 and id<>'4492758' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69398' and id > 4492758 and id<>'4492758' order by id asc limit 5