Authors: Jian Hua Chen, Mao Sheng Yao, Xiao Lin Wang, Juan Juan Feng
Abstract: This paper has systematically investigated the effects of 13 metal ion dopants on the photoreactivity and UV adsorption of TiO2 nanoparticle. The pure and ion-doped TiO2 nanoparticles were prepared using so-gel method. The absorption spectra of the TiO2 nanoparticles were obtained using UV-Visible spectrometer. The wavelength of the absorption edge of TiO2 was calculated using the tangent method. In general, different doping ion types were observed to exhibit different effects on the absorption spectra and photoreactivity of TiO2 nanoparticles. Ion concentrations were also shown to play a important role in the photoreactivity of the catalyst except Ag+, La3+, Zn2+ ions. Results reveal that red shift occurred to all ion-doped TiO2 nanoparticles with absorption edge ranging from 426 nm to 437 nm under optimal ion concentrations. Photocatalysis was shown to be inversely proportional to the amount of red shift of the absorption edge of implanted TiO2. Among the ions investigated, Ni-doped TiO2 nanoparticles have shown highest photoreactivity at the ion concentration 6.04×1017cm-3. The research results may provide references about enhancing the photoreactivity of TiO2 nanoparticles by applying metal ion doping.
2722
Authors: Gaurang Patel, M.B. Sureshkumar, Purvi Patel
Abstract: The transmittance, absorbance, and reflectance of PMMA/TiO2 composites, in different weight percentage of TiO2, prepared by a solution cast technique are investigated. The Optical transmission and UV-VIS absorption spectra have been recorded in the wavelength range 200nm-800nm for different compositions of TiO2 doped PMMA polyfilms. The absorption coefficient, optical (Direct/Indirect) energy gap, Refractive index, Optical Dielectric constant, Constant B, ratio of carrier concentration to the effective mass have been evaluated. The effects of doping percentage of TiO2 on these parameters have been discussed and behaviors of all parameters are investigated.
3249
Authors: Li Zhang, You Nian Liu, Min Jie Zhou, Jian Hui Yan
Abstract: Oxygen generation from halate solution under ultraviolet irradiation was studied. The results show that with regard to KBrO3, KIO3, and KClO3 solution containing 9mmol of halate ions, and the average rates of oxygen formation were 14.1, 10.2 and 2.5 mmol, respectively in the first 3 hours. The rates and amount of oxygen formation increased with increasing halate concentration. The oxygen evolved from the oxidation of water by the excited radical (XO3 ) formed from UV absorption of XO3− ions, resulting in the reduction of halate ions to halide ions
377
Authors: Hai Lang Ju, Zong Liang Mao
Abstract: LiNbO3 is an important crystal which has piezoelectric, ferroelectric and electro-optical functions. It has a wide range of applications. Transmission and reflection spectrum of the LiNbO3 samples on the infrared-visible-ultraviolet light have been measured.The wavelength range is 200nm-2000nm. The transmission and reflection spectrum. The absorption coefficient was calculated by transmission and reflection spectrum. The absorption coefficient of the three samples increased slightly in the beginning of the scanning. Then there was a sudden change upward near 8.4*1014 Hz. Forbidden band Eg was obtained from absorption spectrum. The Eg of the three samples were obtained as 3.996ev,3.407ev and 3.425ev respectively. Forbidden band of LiNbO3 crystals was decreased as the iron doped.
87
Authors: Qiang Wang, Ling Na Sun, Chang Wen Hu, Chuan Bao Cao
Abstract: With the continuous development of Electronic Warfare Technology (ECM) and new requirements of military modernization, stealthy technology played an important role in military equipment. Mechanism of new stealthy continues to be broken through and numbers of successful developments of new types of stealthy materials are put into use. New stealthy materials are the basis and key of stealthy technology and their developments are promoted by the improvements of detection and guidance of military technology. The studies of new stealthy functional nano-materials are analyzed and the stealthy mechanism of functional materials is introduced. The research progress, classification, preparation methods and the radar absorption mechanism of stealthy for new stealthy functional nano-materials are discussed. The new stealthy functional nano-materials are compared with the traditional radar absorption materials. The development trend and application prospects of stealthy functional nano-materials are also estimated.
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