Oblique colisional effects of dust acoustic waves on nonlinear coefficients C_1N of rightward traveling KdV solitons for (a) T_i(e) taking with n_2d(1d) = 0.1, n_i(1d) = 0.4, Z = 0.04, T_1d(i) = 10^–5, T_2d(i) = 10^–4, v_phξ = 0.045, v_phη = 0.045, M_1d(2d) = 150, θ = 45° and U₀ = 0.09; (b) Z taking with κ_e = 2, T_i(e) = 0.1, and the remaining parameters are the same as those in Fig. 1(a).