Phase I:no phase change(no solidification) Tissue (organ) OT O'T T。 =d 8t Ox2 Cooling bath Initial:T(x,0)=T -L≤x≤L -L OL Boundary: OT =0 xx-o 8x x=L -0Phase I: no phase change (no solidification) ( ) Boundary: 0 Initial: ( ,0) 0 2 2 e x L x i T T k h x T x T T x T L x L x T t T                      Cooling bath Te x -L 0 L Tissue (organ)