Papers by Author: Yun Ping Di

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Authors: Li Hua Xu, Fang Lian, Li Chen, Yun Ping Di, Ming Liu, Wen Xia, Bin Xu, Yun Yao
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Authors: Yun Ping Di, Wen Li Zhang, Li Hua Xu, Chang An Wang, Ren Bin Shi
Abstract: The uniform and transparent nano-crystalline thin films of pure and co-doped with Fe3+/Sn4+ titanium dioxide photo-catalysts were prepared via sol-gel dip-coating process, and were loaded firmly on the surface of glass substrates. The structure and surface morphology of films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). In particular, the photo-catalytic activity of films was measured by ultraviolet-visible (UV-VIS) spectrophotometer. Methyl orange was used as a model compound to study the photo-catalytic activity of films. The effects of the concentrations of doping ions and the number of layers on photo-catalytic degradation of methyl orange solutions were investigated. Experimental results showed clearly that the co-doping of iron and tin ions exhibited a synergistic effect, which increased significantly the photo-catalytic activity of titanium dioxide. Especially, the photo-catalytic activity of nano-crystalline titanium dioxide thin films co-doped with 0.1 mol%Fe3+ and 11.41mol%Sn4+ was 2.0 times higher than that of those un-doped for photo-degradation of methyl orange solutions under the 125W self-ballasted fluorescent high-pressure mercury lamp irradiation.
1956
Authors: Ming Liu, Li Hua Xu, Xiao Meng Zhang, Hong Shun Hao, Yun Ping Di
Abstract: In this paper, the research mainly focused on utilization of iron ore tailing of Panzhihua region. Based on the analysis of its components, Carbothermal Reduction Nitridation (CRN) method was selected to synthesize eco-friendly composite material. Different additives were tried to improve the property of the samples. The influence of different sintering temperature, holding time and contents of additives were taken into account, and orthogonal design was employed to obtain the optimal parameters. It indicated that only when the temperature was 1450°C and the holding time was 5 hours, the samples with the bulk density of 3.42g/cm3 was obtained. The phase and surface morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the phases of the product were Fe3Si and TiC0.3N0.7. The research provided a novel recycling process for ore tailings.
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Authors: Li Hua Xu, Xiao Meng Zhang, Fang Lian, Yun Ping Di, Huan Wang, Ming Liu, Ti Zhuang Wang, Wen Chao Li
Abstract: SiAlON family matrix materials have been fabricated from nonmetallic mine. The process of Carbothermal Reduction and Nitridation (CRN) is selected on the basis of raw rocks containing various Si/Al ratios. Thermodynamic analysis of Si-Al-O-N system at different sintering temperatures indicates once the temperature is above 1673 K, a series of chemical reactions occur in sequence, SiO2, SiO, Si2N2O, SiO2+Al2O3, mullite, X-SiAlON, O′-SiAlON, β-SiAlON, SiAlON- polytypiods and Si3N4+AlN. Moreover, most of the reactions are exothermal and are promoted by further heating. The adding or in-situ formed SiC can reduce mullite and Al2O3 to produce O′- or β-SiAlON, and its reaction is surprisingly endothermic and is inhibited when further heated. Also, atmosphere is essential to affect the sintering process. Either raising N2 partial pressures or reducing CO partial pressures can accelerate CRN progress. Correspondingly, phase content and microstructure of the product converted from nonmetallic ore are in detail investigated via X-ray diffraction (XRD) and scanning electron microscopy (SEM).
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