... = 2( a,+b,)h+ (2a,+2b, +27 r*l)h+ 2( 2(a,+b,)l+ 7r.l') = 2( 21,5 + 93) .24 + (2. 21,5 + 2. 93 + 27 x 11,5) .24 + + 2( 2 (21 ,5+ 93).11,5 +71.11,5') = 18 824 ,11 (mm') = 0,018 82 m' Vay: At = 16,5/(14.0,018 82) ... 14 W/m'.°C ST = 2( a,+b|)h+ (2a,+2b| +27 r*l)h+ 2( 2(a,+bi)l + 7r.l') = 2( 21,5 + 93) .24 + (2. 21,5 + 2. 93 + 27 r.l 1,5) .24 + + 2( 2 (21 ,5+ 93).l 1,5 + 71.11,5') = 18 824 ,11 (mm') = 0,018 82 m' Vay: At =13,48/(14.0,018 82) ... thep chiT U: Thep s 221 2 122 116 115 Vdt 45° _2R1 R2,5 7_^ CM O 2R0,4 "nr-R.1 T 4^ i J00,8_ J26_ 130 La thep chu' T: Thep s 221 2 42 ^ •"I- 00 CD 4,01 rj R4 _ ^C - ^! 2j 88-0 02 27/ 72 t Gia dau cuon...