  The fusion-fission process accompanied by neutron emission is studied in the
superheavy-mass region on the basis of the fluctuation-dissipation model
combined with a statistical model. The calculation of the trajectory or the
shape evolution in the deformation space of the nucleus with neutron emission
is performed. Each process (quasi-fission, fusion-fission, and deep
quasi-fission processes) has a characteristic travelling time from the point of
contact of colliding nuclei to the scission point. These dynamical aspects of
the whole process are discussed in terms of the pre-scission neutron
multiplicity, which depends on the time spent on each process. We have
presented the details of the characteristics of our model calculation in the
reactions $^{48}$Ca+$^{208}$Pb and $^{48}$Ca+$^{244}$Pu, and shown how the
structure of the distribution of pre-scission neutron multiplicity depends on
the incident energy.
