For a sample of 411 type II QSOs with redshifts less then 0.3, we use the Balmer decrements to do the reddening correction of the [O III] luminosities and then derive the intrinsic [O III] luminosity function. We find that the host reddening correction of the [O III] 5007 luminosity for type II QSOs cannot be neglected. The median Balmer decrement of Hα/Hβ=4.0 corresponds to an extinction of 0.94 mag for the [O III] 5007 line, which is consistent with the result derived from the median Hβ/Hγ. Comparing the intrinsic luminosity function of type II QSOs with that of type I QSOs, we find that the upper limit of the type II QSO’s fraction in the total QSOs is 80% for type II QSOs with z < 0.3 and 8.6⩽log (L[O III]/L⊙)⩽9.4.
A novel method for the determination of nucleic acid at nanogram levels was developed based on the measurement of resonance
light scattering (RLS) signals of 3,3′-dichlorobenzidine (DCB). In the Britton-Robinson buffer (pH 2.21), the weak light scattering
of DCB was greatly enhanced by addition of calf thymus DNA (ctDNA), the maximum RLS peak is at 346 nm and the enhanced intensity
of RLS is in proportion to the concentration of ctDNA. The linear range is 0.05–5 μg mL−1 for ctDNA, and the detection limit is 14 ng mL−1 (3σ). DNA in synthetic samples was analyzed with satisfactory results. 相似文献
This paper investigates the maximum principle for viscosity solutions of fully nonlinear, second order parabolic, possibly degenerate partial differential equations. Using this maximum principle the anthor prove that viscosity solutions of initial and bo unoary value problem for parabolic equations are unique. 相似文献
In this work, ZnO particles with different morphologies were successfully prepared by a simple solution route at low temperature. The products were characterized by SEM, EDS, XRD, TEM, HRTEM, SAED, TG–DTA and UV–Vis DRS. To further understand the formation processes of these ZnO particles, XRD analyses of the intermediates and concentration measurements of Zn(II) remaining in the reaction solution were made at regular intervals throughout the reactions. A possible formation mechanism is discussed. Photocatalytic activity of the as-prepared ZnO powders, evaluated by degradation of pentachlorophenol under UV irradiation, is found to be closely related to the particle morphology. 相似文献