  Following a recent rapid communications[Phys.Rev.C85,021302(R) (2012)], we
present more details on the investigation of the relativistic symmetry by use
of the similarity renormalization group. By comparing the contributions of the
different components in the diagonal Dirac Hamiltonian to the pseudospin
splitting, we have found that two components of the dynamical term make similar
influence on the pseudospin symmetry. The same case also appears in the
spin-orbit interactions. Further, we have checked the influences of every term
on the pseudospin splitting and their correlations with the potential
parameters for all the available pseudospin partners. The result shows that the
spin-orbit interactions always play a role in favor of the pseudospin symmetry,
and whether the pseudospin symmetry is improved or destroyed by the dynamical
term relating the shape of the potential as well as the quantum numbers of the
state. The cause why the pseudospin symmetry becomes better for the levels
closer to the continuum is disclosed.
