  A numerical method to solve the TDHFB equations by using a hybrid basis of
the two-dimensional harmonic oscillator eigenfunctions and one-dimensional
Lagrange mesh with the Gogny effective interaction is applied to the head-on
collisions of the superfluid nuclei ${}^{20}$O's. Taking the energies around
the barrier top energy, the trajectories, pairing energies, and numbers of
transferred nucleons are displayed. Their dependence on the relative gauge
angle at the initial time is studied by taking typical sample points of the
gauge angle. It turned out that the functional form of the flux of the neutrons
across a section plane is proportional to the sine of the two times of the
gauge angle.
