based on the assumption that the electrostatic charges on the surface of sheep leukocytes arise from the dissociation of ionogenic groups , together with the presence of divalent cation ( or trivalent cation ) in the suspending medium of low ionic strength ( or high ionic strength ) , the non-linear poisson-boltzmann equation for cell interaction with a solid surface with constant potential ( or constant charge ) is numerically solved in this paper .
C0007448
divalent cation
C0007447
cation