鸣-0。 鸣心 △S= 0=0-s 18 ∮ T QR  =  B A R I T Q ( ) +  A B R II T Q ( ) =0  B A R I T Q ( ) -  B A R II T Q ( ) =0  B A R I T Q ( ) =  B A R II T Q ( ) ΔS≡ B A R I T Q ( ) =  B A R II T Q ( ) =  B A dS