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The spin wave dispersion relation for the grain-surface-layer region is calculated by assuming that the anisotropy constant Ks and the anisotropy field Hs in the gain-surface-layer region are different from the other region. In comparison with the manifold of the grain-interior, the resonance region, for the grain-surface-layer region is much broader than that for the grain-interior. The high field and the low field effective linewidths are given respectively: ΔHeff=2χ+s"Vsf(H)(Hi-ω/γ-S)2/Ms and ΔHeff=2[χ+s"Vsf(H)+χ+b"(1-Vs)](Hi-ω/γ-S)2/Ms, by setting χ+i= χ+b(1-Vs)+χ+sVs, where χ+i is the intrinsic susceptibility, χ+b, Vb=1-Vs, χ+s and Vs denote the susceptibility and the volume fraction respectively for the grain-interior and the grain-surface-layer region. The dependence of ΔHeff on the grain size, porosity, temperature, Ms and H, as well as the field shift S vs. H are explained with this model. The value of Ks≈-2×105 erg/cm3 is estimated by fitting data for YIG and NiZn ferrite. An additional basic channel of energy transfer from the rf field via spin wave system of the grain-surface-layer region to the lattice is suggested for polycrystals.