UV (the upper panel) and X-ray (the lower panel) monochromatic luminosities (in units of erg s⁻¹ Hz⁻¹) of quasars varying with redshifts. The luminosities were obtained from the measured fluxes assuming a standard ΛCDM cosmological model with H₀ = 70 km s⁻¹ Mpc⁻¹ and Ω_M = 0.3. The log L_UV(X) approximately linearly increases with log(1 + z) within the range of redshifts where the statistical quantity of sample is sufficient. The dashed red lines are the optimal linear fits, and k_UV(X) are the corresponding slopes.