A new photon kinetic-measurement based on the kinetics of electron-hole pairs in photodegradation of textile wastewater using the UV-H_2O_(2FS)-TiO_2 process

Actual textile wastewater and synthesized wastewater containing various textile dyes were photocatalytic degraded by the UVH2O2Fs-TiO2 process in an aimular-flow photocatalytic reactor. In this process, a photon kinetic-measure was adopted to obtain constant rates of dyes decomposition. It was theorized that, by illumination at different UV frequencies, the electrons within the semiconductor were excited from the valence band to the conduction band, yielding the formation of electron-hole pairs which are the pre-requisites for photocatalysis. CPT （critical photonic time） exposure required to cause 90% of vibrations between the double and single bonds along the molecular chain of the dyes to be oxidized, was taken to measure the photocatalytic activities. The CPTs varied with the frequencies of the UV spectral areas. The derivatization of CPT from the first-order kinetic law was presented.

Effect of Heat-treatment on Crystalline Phase and UV Absorption of 60CeO_2-40TiO_2 Thin Films by Magnetron Sputtering

60CeO2-40TiO2 thin films were deposited on soda-lime silicate glass substrates by R.F. magnetron sputtering. The effects of heat-treatment on the UV-absorption of the thin films were studied on the 60CeO2-40TiO2 thin film with the largest UV cut-off wavelength. The sample films with CeO2：TiO2=60：40 were heated at 773 K, 873 K, 973 K for 30 min. These films are characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and X-ray photoelectron spectroscopy and spectrometer （XPS）. XRD analysis proves that the addition of TiO2 to CeO2 changed the crystalline state of CeO2. But the UV absorption effect of CeO2-TiO2 films with CeO2 crystallite phase is inferior to that of the amorphous phase CeO2-TiO2 films. XPS analysis also indicates that the amorphous phase CeO2-TiO2 films have the most Ce3＋ content in these films. Amorphous phase and crystalline phase of the CeO2-TiO2 films have different effects on UV absorption of the thin films.

产生高功率UV光硼酸盐晶体的可靠性改进

All solid state UV lasers have been in demand for various industrial and medical applications because of the convenient operation procedure and cost effectiveness as alternative to corrosive gas based excimer laser.The performance of such lasers seems to depend on the capability and reliability of UV frequency converter.In the third decade,CsLiB 6O 10 (CLBO)and Gd xY 1 x Ca 4O(BO 3) 3 (GdYCOB)were developed by the authors group.CLBO is the most effective nonlinear optical crystal to generate high power fourth and fifth harmonics of Nd∶YAG laser.GdYCOB is the first material which can achieve noncritical phase matching (NCPM) condition for THG of Nd∶YAG laser.The NCPM condition is advantageous owing to its large angular acceptance and the elimination of walk off between fundamental and harmonic lights.On the other hand,reliability is very importmat for actual application of these crystals.Here,we will present about techniques to improve durability of NLO crystals for high power UV light generation.For instance,we found that removal of surface polishing compound by means of ion beam etching can imrpove surface durability of CLBO.Also,we will discussed about photo induced damages in GdYCOB and its solution.