A.R1>(R2+R3) B.R1<(R2+R3) C.R1=(R2+R3) D.無法比較
A.恒溫傳熱和穩(wěn)態(tài)變溫傳熱; B.導熱給熱和熱交換; C.氣化、冷凝與冷卻; D.傳導傳熱、對流傳熱與輻射傳熱