  A Skyrme-type momentum-dependent nucleon-nucleon force distinguishing isospin
effect is parameterized and further implemented in the Lanzhou Quantum
Molecular Dynamics (LQMD) model for the first time, which leads to a splitting
of nucleon effective mass in nuclear matter. Based on the isospin- and
momentum-dependent transport model, we investigate the influence of
momentum-dependent symmetry potential on several isospin-sensitive observables
in heavy-ion collisions. It is found that symmetry potentials with and without
the momentum dependence but corresponding to the same density dependence of the
symmetry energy result in different distributions of the observables. The
mid-rapidity neutron/proton ratios at high transverse momenta and the
excitation functions of the total $\pi^{-}/\pi^{+}$ and $K^{0}/K^{+}$ yields
are particularly sensitive to the momentum dependence of the symmetry
potential.
