???? ??? ?? ?? ???? ??? ?? ??? ?? 7?? ??? ?? ?? 200? ??? ????? ?? ???? ??? 0.15~0.17???. ??? ??? ??(7? 26? 24?) ??? ‘3?? ??’? ??? ??? ?? ??? ? ? ????? ??? ???? ????.

7? 20?, ?6?? ????? ?? ?? ???? 4.58%?? ???? ???? 200?/? ???? ???? ??? 0.15~0.17??? ???? ??? 7? 26? 24???.