  The excitation functions of proton elastic scattering on $^{12}$C and
$^{14,15}$O nuclei at the energies near the proton-emission threshold are
calculated using the Skyrme Hartree-Fock (SHF) in continuum approach. For each
excitation function, the first resonance is identified as the $s$-state
resonance of the mean-field theory. For $^{15}$O, whose ground-state spin is
nonzero, the $s$-state resonance splits into two resonances via the spin-spin
component of the optical potential. With a slight adjustment of the strength of
central potential, which is obtained from the SHF in continuum approach, the
excitation functions of proton elastic scattering for the three nuclei can be
explained with high accuracy. The proposed framework can provide a practical
method to explain nuclear scattering at the energies near the proton-emission
threshold with minimal experimental input.
