Λ0(φ,k)=F(φ,1−k2)K(1−k2)+2πK(k)Z(φ,1−k2)=2π(1−k2)sinφcosφΔ(RF(0,1−k2,1)+k23Δ2RJ(0,1−k2,1,1−k2Δ2));Δ2=1−(1−k2)sin2φ