The Experts below are selected from a list of 25515 Experts worldwide ranked by ideXlab platform
Songqin Liu - One of the best experts on this subject based on the ideXlab platform.
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mediator free phenol sensor based on titania sol gel encapsulation matrix for immobilization of tyrosinase by a Vapor Deposition Method
Biosensors and Bioelectronics, 2003Co-Authors: Songqin LiuAbstract:A novel amperometric phenol sensor was constructed by immobilizing tyrosinase in a titania sol–gel matrix. The tyrosinase entrapped sol–gel film was obtained with a Vapor Deposition Method, which simplified the traditional sol–gel process and avoided the shrinkage and cracking of conventional sol–gel-derived glasses. This matrix provided a microenvironment for retaining the native structure and activity of the entrapped enzyme and a very low mass transport barrier to the enzyme substrates. Phenol could be oxidized by dissolving oxygen in presence of immobilized tyrosinase to form a detectable product, which was determined at −150 mV without any mediator. The phenol sensor exhibited a fast response (less than 5 s) and sensitivity as high as 103 μA/mM, which resulted from the porous structure and high enzyme loading of the sol–gel matrix. The linear range for phenol determination was from 1.2×10−7 to 2.6×10−4 M with a detection limit of 1.0×10−7 M. The apparent Michaelis–Menten constant of the encapsulated tyrosinase was calculated to be (0.29±0.02) mM. The stability of the biosensor was also evaluated.
Changqing Sun - One of the best experts on this subject based on the ideXlab platform.
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a new amperometric sensor for the determination of bromate iodate and hydrogen peroxide based on titania sol gel matrix for immobilization of cobalt substituted keggin type cobalttungstate anion by Vapor Deposition Method
Sensors and Actuators B-chemical, 2005Co-Authors: Changqing SunAbstract:Abstract A new amperometric sensor was fabricated based on the immobilization of complex of Na 2 H 6 CoW 11 Co(H 2 O)O 39 ·14H 2 O (CoW 11 Co) and poly(4-vinylpyridine) (PVP) in a TiO 2 sol–gel matrix by Vapor Deposition Method. The preparation process simplified the traditional sol–gel process and prevented the cracking of conventional sol–gel derived glasses. The electrochemical behavior of the new amperometric sensor was studied in detail by cyclic voltammetry, and three reversible two-electron redox waves were observed in acidic aqueous solution in the potential range of −0.1 to −0.7 V. The sensor displays good electrocatalytic activity toward the reduction of bromate, iodate and hydrogen peroxide in acidic aqueous solution and the catalytic mechanisms were also discussed. The catalysis of the sensor towards bromate and iodate was systematically studied by amperometric Method. The Method gave a linear range from 2.0 × 10 −5 to 4.4 × 10 −3 M and a detection limit of 5.0 × 10 −6 M for BrO 3 − and 2.0 × 10 −6 to 2.8 × 10 −4 and 8.0 × 10 −7 M for IO 3 − , respectively. In addition, the sensor has some distinct advantages over the traditional polyoxometalate sensor, such as simple preparation process, fast response and long-term stability.
Cheol Jin Lee - One of the best experts on this subject based on the ideXlab platform.
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Single-Crystalline ZnO Microtubes Formed by Coalescence of ZnO Nanowires Using a Simple Metal-Vapor Deposition Method
Chemistry of Materials, 2005Co-Authors: Jong Seok Jeong, Jeong Yong Lee, Jung Hee Cho, Han Jong Suh, Cheol Jin LeeAbstract:Single-crystalline ZnO microtubes were synthesized by a simple metal-Vapor Deposition Method. The ZnO microtubes, which had outer diameters in the range of 0.3−2 μm and wall thickness in the range of 100−500 nm, indicated a faceted hexagonal shape. In addition, it was found that there were many incomplete ZnO microtubes, which indicate the morphology assembled with several nanowires at the tip part of the microtubes and prismatic tubular morphology at the bottom part of the microtubes. It is suggested that the ZnO microtubes were formed by the coalescence of ZnO nanowires due to a high reaction temperature of 950 °C and optimized oxygen supplement when ZnO nanowires were grown on a large ZnO grain. We discuss the growth mechanism of the ZnO microtubes in detail.
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Synthesis of high-purity GaP nanowires using a Vapor Deposition Method
Chemical Physics Letters, 2002Co-Authors: Seung Chul Lyu, Ye Zhang, Hyun Ruh, H. J. Lee, Cheol Jin LeeAbstract:Abstract High-purity gallium phosphide (GaP) nanowires were successfully synthesized on the nickel monoxide (NiO) or the cobalt monoxide (CoO) catalyzed alumina substrate by a simple Vapor Deposition Method. To synthesize the high-purity GaP nanowires, the mixture source of gallium (Ga) and GaP powder was directly Vaporized in the range of 850–1000 °C for 60 min under argon ambient. The diameter of GaP nanowires was about 38–105 nm and the length was up to several hundreds of micrometers. The GaP nanowires have a single-crystalline zinc blend structure and reveal the core-shell structure, which consists of the GaP core and the GaPO4/Ga2O3 outer layers. We demonstrate that the mixture of Ga/GaP is an ideal source for the high-yield GaP nanowires.
Xian Luo - One of the best experts on this subject based on the ideXlab platform.
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Grain-scale growth simulation of SiC film with the Chemical Vapor Deposition Method
Computational Materials Science, 2012Co-Authors: Cuixia Liu, Yanqing Yang, Xian LuoAbstract:Abstract Grain-scale growth of SiC film prepared by the Chemical Vapor Deposition Method is simulated with finite difference Method in two-dimensional scale. The morphology and crystallographic texture of SiC film, such as evolution of grain size, surface roughness, grain boundary evolution and contribution of various crystal planes, are analyzed with growth-rate parameter. The results show that the Deposition temperature affects growth-rate parameter. With the increase of SiC thickness, SiC grain becomes thicker and bigger. Surface of SiC film becomes more and more rough. When the value of growth-rate parameter is 1.95, the surface of SiC film seems to be a “flat roof shape”. SiC crystal is mainly composed of {1 1 1} plane, {1 1 0} plane and {1 0 0} plane. 〈1 1 0〉 orientation is preferential orientation. When the value of growth-rate parameter is 6.28, the surface of SiC film seems to be a “sharp roof shape”. SiC crystal is totally composed of {1 1 1} plane. 〈1 0 0〉 orientation is preferential orientation. Those preferential orientations are mainly controlled by crystal structure.
Ye Zhang - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of ZnO nanocrystals with novel hierarchical structures via atmosphere pressure physical Vapor Deposition Method
Journal of Crystal Growth, 2006Co-Authors: Youguo Yan, Ye Zhang, Guowen Meng, Lide ZhangAbstract:The search for hierarchically organized ZnO nanocrystals have been intense in recent years, due to both fundamental interest in nanocrystal growth subjects and their potential applications as components for building nanodetectors, optoelectronic, vacuum microelectronic, and spintronic nanodevices. We reported the first observation of a variety of novel nanostructures, such as nanocandle arrays, wine-bottle-shaped rod arrays, nanorivet arrays, periodic diamond-string and needle arrays, nanofern and needle arrays, tooth-shaped belt, spinal-shaped nanostructures and bamboo-shaped nanorod via an atmosphere pressure physical Vapor Deposition Method. The unique feature of our Method is atmosphere chamber pressure, which can induce chaos and fluctuation of source Vapor and facilities multiply growth mechanisms to have competing dominating effects on the crystal growth of ZnO. The SEM and photoluminescence spectra confirm that those nanostructured ZnO crystals possess satisfactory structural and optical qualities.
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low temperature growth of zno nanowire array by a simple physical Vapor Deposition Method
Chemistry of Materials, 2003Co-Authors: Ye ZhangAbstract:Well-aligned single-crystalline wurzite zinc oxide (ZnO) nanowire array was successfully fabricated on an Al2O3 substrate by a simple physical Vapor-Deposition Method at a low temperature of 450 °C. The diameter and growth rate of ZnO nanowires increased as a function of growth temperature. TEM observation showed that the ZnO nanowires were synthesized along the c-axial direction of the hexagonal crystal structure. We demonstrate that ZnO nanowires followed the self-catalyzed growth mechanism on the ZnO nuclei. Besides high-quality ZnO nanowires, sometimes a fascinating hierarchically ordered ZnO structure was also observed.
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Synthesis of high-purity GaP nanowires using a Vapor Deposition Method
Chemical Physics Letters, 2002Co-Authors: Seung Chul Lyu, Ye Zhang, Hyun Ruh, H. J. Lee, Cheol Jin LeeAbstract:Abstract High-purity gallium phosphide (GaP) nanowires were successfully synthesized on the nickel monoxide (NiO) or the cobalt monoxide (CoO) catalyzed alumina substrate by a simple Vapor Deposition Method. To synthesize the high-purity GaP nanowires, the mixture source of gallium (Ga) and GaP powder was directly Vaporized in the range of 850–1000 °C for 60 min under argon ambient. The diameter of GaP nanowires was about 38–105 nm and the length was up to several hundreds of micrometers. The GaP nanowires have a single-crystalline zinc blend structure and reveal the core-shell structure, which consists of the GaP core and the GaPO4/Ga2O3 outer layers. We demonstrate that the mixture of Ga/GaP is an ideal source for the high-yield GaP nanowires.
