  We study the RH neutrino properties from the low energy neutrino data in the
seesaw mechanism. Reonance behavior is found for the right-handed (RH) mixing
angle as a function of light neutrino mass ratios in two favored region of the
solar neutrino problem and, at the resonance point, the two corresponding RH
Majorana neutrino masses are degenerate. This phenomenon is similar with that
in the matter-enhanced conversion of neutrinos. The physical significance it
infers for the electron neutrino mass and other neutrino parameters is
discussed.
