Visible-light-driven N-doped TiO 2 was prepared by a simple sol-gel process using nitric acid not only as the acid catalyst of the sol-gel reaction but also as the source of nitrogen. The photocatalytic performance of the N-doped TiO 2 was investigated by using FTIR spectroscopy to monitor the degradation of trichloroethylene (TCE) during UV and visible irradiation. The photocatalytic degradation of TCE was well-reproduced several times. The activity of Ti-O-N species was supported experimentally. The N-doped TiO 2 was found to be responsive to visible light and was stable during repeated runs and maintained the nitrogen species and its activity for at least four months.
Degradation of three chlorinated ethenes, trichloroethylene, trans-1,2-dichloroethylene and cis-1,2-dichloroethylene, by UV-light irradiatedTiO2catalyst prepared by the sol-gel method in dry air at ambient temperature have been examined by using FTIR measurement. The chlorinated ethenes rapidly decomposed to produce dichloroacethyl chloride, CO, HCl, andCOCL2. For trans- and cis-1,2-DCE systems isomerization to each other is found to be the first step of the degradation. The C = C bond of the chlorinated ethenes interacts directly withTiO2site and, consequently, the degradation results in several products on the catalyst surface in these systems.
Abstract— The resolution and image quality of small‐screen CRTs have been analyzed. The resolution is primarily determined by the size of the luminous spot, which is determined both by the electron gun and by the size of phosphor particles. Image quality on phosphor screens is controlled by the packing density of the phosphor particles and by the number of layers of phosphor particles in the screen. We have developed a phosphor screen with 1.5 layers of phosphor particles in which packing voids have been minimized by the use of dusting techniques. The new phosphor screen used in a 0.5‐in. CRT is capable of displaying sharp SVGA images (1000 × 800 pixels) that are comparable in quality with the images on 13‐in. CRTs.
The fluorescence excitation and emission spectra of xerogels containing 1,2-bis(9-acetoxy-lO-anthryl)ethane (AAEA) encapsulated into -0-Si -0networks, prepared by the sol-gel processing of tetraethyl orthosilicate (TEOS), have been observed at room temperature. AAEA encapsulated in a xerogel pore showed photochromic behaviour in its fluorescence spectra, indicating excited-state conformational relaxation from the trans to the gauche form by photoexcitation. Differences in the water-TEOS mixture ratio in the starting solution led to different photochromic behaviour in the xerogel state. A rise and decay of fluorescence intensities were observed in water-rich specimens. The diameter of the pores of the prepared xerogel was estimated at > 20 A.
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