Papers by Author: Pei Xin Zhang

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Authors: Xiang Zhong Ren, Pei Xin Zhang, Jian Hong Liu, Qian Ling Zhang
Abstract: Ag/polypyrrole(PPy) composite nanoparticles within 100 to 150nm diameter were successfully synthesized. Fourier transform infrared spectroscopy(FTIR) and X-ray diffraction patterns(XRD) data suggested that the nanoparticles were composed of Ag and PPy. An amperometric glucose biosensor was fabricated by adsorbing of glucose oxidase(GOx) to an Ag/PPy nanoparticle-ethyl cellulose composite material modified platinum electrode. The biosensor exhibited a super highly sensitive response to the analyte with a detection limit of 1.0×10-7mol/L. Moreover, the biosensor showed quick current response. The effects of some factors, such as working voltage, pH value , mensuration temperature and mass ratio of Ag/PPy nanoparticles to ethyl cellulose, were also studied.
Authors: Xiang Zhong Ren, Li Zhang, Ying Kai Jiang, Pei Xin Zhang, Jian Hong Liu, Qian Ling Zhang
Abstract: AgCl@polypyrrole(PPy) nanocomposites were synthesized through in situ chemical oxidation polymerization by using poly(vinylpyrrolidane) (PVP) as dispersant, and some Au colloid were prepared by using KBH4 as reductant and sodium citrate as stabilizer, then the Au nanoparticles-AgCl@PPy hybrid material was formed by physical chemical reaction. Fourier transform infrared spectrometer (FTIR) and electron dispersive spectrometer (EDS) data suggested that the hybrid material were composed of Au, AgCl and PPy. An amperometric glucose biosensor was fabricated by adsorbing glucose oxidase (GOx) to an Au nanoparticles-AgCl@PPy hybrid material modified platinum electrode. The biosensor exhibited a super highly sensitive response to H2O2.
Authors: Pei Xin Zhang, Mu Chong Lin, Qiu Hua Yuan, Zhen Zhen Fan, Xiang Zhong Ren, Dong Yun Zhang
Abstract: With the acetates of nickel, manganese and cobalt as raw materials and lithium hydroxide as precipitation agent, the precursor Ni1 / 3 Co1 / 3 Mn1 / 3 (OH) 2 was first prepared by chemical coprecipitation method, which was then mixed and ballmilled with certain stoichiometric ratios of LiOH∙H2O, and ultimately obtained LiCo1/3Mn1/3Ni1/3O2 after calcination process. Single-factor experiment method, in conjunction with XRD, SEM, and charge-discharge test, was utilized to study the influence of various factors, including the dispersion way of precursor, pH value of reaction solution, and the content of ballmilling lithium on the electrochemical properties of LiCo1/3Mn1/3Ni1/3O2. The results indicated that: (1) the material dispersed by ultrasonic treatment revealed excellent cycling performance, its ratio of capacity fading decreased at least 34.1% compared to those without ultrasonic process; (2) the optimum conditions of fabricating LiCo1/3Mn1/3Ni1/3O2 may be summarized as the treatment of ultrasonic dispersion, suitable pH value (12~13) and stoichiometric ratio (1.0) of ballmilling lithium.
Authors: Pei Xin Zhang, Li Gao, Qiu Hua Yuan, Hai Lin Peng, Xiang Zhong Ren, Dong Yun Zhang
Abstract: The glass-ceramics of MgO-Al2O3-SiO2 system were prepared by sintering technology. The crystallization process of MgO-Al2O3-SiO2 glass-ceramics was investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM), and other techniques; the discussion of breaking strength, thermal expansion coefficient and relevant properties at different sintering temperatures was also presented. The results show that: (1) The main crystalline phase isα-cordierite at different sintering temperatures, and the samples show high flexural strength and low thermal expansion coefficient; (2) with the increase of sintering temperature, the content of crystal phase increases, while the thermal expansion coefficient decreases evidently, the flexural strength and tightness density rise up first, then go down.
Authors: Qian Qian Hou, Pei Xin Zhang, Ming Fang Zhang, Zheng Wu Lu, Xiang Zhong Ren
Abstract: Compared with traditional lighting, LED has many unparalleled advantages, and is considered to be the most promising green light which may be able to substitute incandescent and fluorescent lamps. The requirement of LED's luminous efficiency grows with its increasingly application in the lighting field. This paper summarizes the development of gaining approaches of Power-type WLED and their respective advantages and disadvantages; analyses several effective programs which can improve luminous efficiency, including changing substrate materials as to enhance the heat-release performance as well as the impact of chip structure design, the packaging materials and technology or other factors; proposes a new LED packaging material- inorganic fluorescent glass, which is expected to simplify the packaging process greatly, at last, there is an expectation of High-power WLED in future application.
Authors: Qiu Hua Yuan, Pei Xin Zhang, Li Gao, Hai Lin Peng, Xiang Zhong Ren, Dong Yun Zhang
Abstract: The crystallization behavior of MgO-Al2O3-SiO2 glass-ceramics by sol-gel technology was investigated by using x-ray diffraction (XRD), differential thermal analysis (DTA), Scanning electron microscopy (SEM). The results showed that: (1)α-cordierite phase was precipitated when the green body was calcined at 1050°C, and α-cordierite of high purity and stability could be formed at 1100°C; (2) Adding an appropriate amount of low melting point glass powder into the green body may provide liquid-phase environment during the sintering process, which will help enhance the tightness density of glass-ceramic, and thus improve its flexural strength.
Authors: Dong Yun Zhang, Li Zhang, Pei Xin Zhang, Mu Chong Lin, Xiao Qian Huang, Xiang Zhong Ren, Qi Ming Xu
Abstract: In order to improve the electrochemical performance of LiFePO4, Li0.99Nb0.01FePO4/C composite materials were synthesized with citric acid coating and Nb2O5 doping. The physical chemistry and electrochemical performances of Li0.99Nb0.01FePO4/C were investigated by X-Ray diffraction (XRD) and Transmission electron microscope (TEM). The results show that Li0.99Nb0.01FePO4/C has smooth charge-discharge voltage platform, with first capacity of 151.6 mAh•g-1 (0.1C) and no obvious capacity fading after 16 cycles. The materials have favorable high rate discharge performances, with the first capacity of 131.6 mAh•g-1 at 0.5C, 119.8 mAh•g-1 at 1.0C and 106.2 mAh•g-1 at 2.0C. Equivalent circuits analysis shows that the impedance, especially electrode reaction resistance of Li0.99Nb0.01FePO4/C are significantly reduced compared with the pure LiFePO4 and this helps to improve the electric conductivity, discharge capacity and cycle performance. The diffusion coefficient of Li+ in Li0.99Nb0.01FePO4/C is 2.51×10-12 cm2•s-1 increased two orders of magnitude in comparison with the pure LiFePO4. Carbon-coating makes a more remarkable contribution to lithium diffusion than Nb5+ ion doping.
Authors: Hai Yang Li, Zhong Kuang Luo, Hong Hua Cai, Jian Hong Liu, Pei Xin Zhang, Xun Liang, Xiang Zhong Ren
Abstract: TiO2 coatings on ceramic substrate were prepared using TiOSO4 and silica sol. Coatings were then heat-treated respectively at 300°C, 400°C or 500°C for 30mins. Degradation of the solution of chlorinated methane by UV light and TiO2 coating were investigated. It can be concluded from the results that the coating with composition of 80wt%TiO2-20wt%SiO2 heated at 500°C display better degradation effect than the other coatings. As the initial concentration of chloromethane goes up, the degradation rate increases; while as the degree of substitution by chlorine goes up, the catalytic effects decreases.
Authors: Xin Min Wang, Bo Liu, Hong Hua Cai, Zhong Kuang Luo, Xiang Zhong Ren, Jian Hong Liu, Pei Xin Zhang, Fang Wang
Abstract: WO3 sol was prepared through the sol-gel process. Ethanol, acetone and SiO2 sol were added to the WO3 sol. The WO3 thin films on glass substrate were obtained with the hybrid sol by the dip-coating technique, and then were heat-treated at different temperatures for a certain time. X-ray diffractometer and scanning electron microscope were used to characterize the crystal structure and surface morphology of these coatings. Visible light transmittance changes of the thin films irradiated under UV light were measured with UV spectrometer. The experimental results demonstrated that photochromic effect, hardness and uniformity of thin films were improved when the thin films are obtained with the hybrid sol.
Authors: Xiang Zhong Ren, Xi Li, Pei Xin Zhang, Jian Hong Liu, Qian Ling Zhang
Abstract: LiFePO4/PPy composites with different content of polypyrrole (PPy) were prepared by chemical oxidation reactions. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the LiFePO4/PPy composite. The results showed that doped PPy did not destroy the olivine structure of LiFePO4 but decreased the intensity of the diffraction peaks, and PPy was found on the surface of LiFePO4 particles. PPy could remarkably increase the conductivity of the composite and improve the electrochemical performance of LiFePO4. The sample with 2.5 % (wt). PPy possessed a high initial discharge capacity of 144.5mAh/g at 0.1C. The results of both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) proved good cycle performances of the samples doped by PPy.
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