dfrac (1)(32) ;-|||-D.1;

dfrac (1)(2)-|||-○ D.1

dfrac (1)(2)-|||-D.1

dfrac (1)(2) C. -1 D.1

sqrt (2) C. dfrac (sqrt {2)}(2) D.1

(B) dfrac (11)(32) . (C) dfrac (1)(2) . (D) dfrac (3)(8) .

产生污垢后,总传热系数为=dfrac (1)(dfrac {d)({d)_(1)(d)_(1)}+(R)_(5)dfrac ({d)_(1)}({d)_(1)}

dfrac (1)(7)-|||-C dfrac (1)(15)-|||-D dfrac (1)(3)

dfrac (1)(2)-|||-C dfrac (1)(6)-|||-D . dfrac (1)(36)

(B) =2, =dfrac (1)(3).-|||-(C) =1, =dfrac (1)(2). (D) =1, =-dfrac (1)(3),求指导本题解题

-dfrac (1)(pi )-|||-D. dfrac (1)(pi )