  Extensive calculations on isoscaling behavior with the sequential-decay model
gemini are performed for the medium-to-heavy nuclei in the mass range A =
60-120 at excitation energies up to 3 MeV/nucleon. The comparison between the
products after the first-step decay and the ones after the entire-steps decay
demonstrates that there exists a strong sequential decay effect on the final
isoscaling parameters and the apparent temperature. Results show that the
apparent symmetry energy coefficient $\gamma_{app}$ does not reflect the
initial symmetry energy coefficient $C_{sym}$ embedded in the mass calculation
in the present GEMINI model.
