Papers by Author: Qiang Li

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Authors: Chang Tian Huan, Jin Feng Xia, Dan Yu Jiang, Qiang Li
Abstract: This paper compares the low-temperature aging performance of 5Y-TZP and 8Y-TZP by coprecipitation and solid-phase synthesis methods in the steam. Analysis the weight changes of samples using analytical balance, and the sample surface microstructure and phase changes with SEM, XRD. The results show that the content of Y2O3 and synthesis method all affect the aging properties of zirconia ceramics; solid-phase synthesis of 8Y-TZP has the best anti-aging performance.
435
Authors: Cai Xia Li, Peng Fei Zhu, Dan Yu Jiang, Qing Lv, Qiang Li
Abstract: LBL (layer by layer) fabrication was based on the electrostatic attraction between the nanosheets host partial with electric charges and external object with opposite charges. By changing the property of the object, level defects can also be introduced, so that the nano-films with remarkable physica-chemical properties can be prepared. Tantalum oxide and cobalt oxide nano-films materials were made via LBL self-assembly technology in this work
1696
Authors: Jing Chu, Dan Yu Jiang, Na Zhang, Min Zhang, Qiang Li
Abstract: Nano-structured Barium Titanate (BaTiO3) was prepared by a hydrothermal method with the reaction between metatitanic acid and an alkaline solution of Ba(OH)2•8H2O. The morphology of as-obtained powders of BaTiO3 was determined by Scanning Electron Microscope, which revealed that well-dispersed nanoparticles were successfully synthesized. The phase composition was analyzed by X-ray diffraction, which shows that cubic phase of Barium Titanate was prepared. The optimal reaction conditions were discussed in detail.
311
Authors: Li Li, Cheng Zhang, Tao Feng, Hai Feng Xu, Qiang Li
Abstract: Eu2+ Doped Ca-α-SiAlON phosphor have been synthesized from SiO2, Al2O3, CaCO3, Eu(NO3)3,carbon powders by carbothermal reduction–nitridation (CRN). Using X-ray Diffractometer (XRD) and fluorescent spectrophotometer, the influences of the phase content of the sintered samples after different soaking time at 1390°C and their luminescence properties were studied. The pure Ca-α-SiAlON:Eu2+ were prepared at processing temperatures of 1390°C in a holding time of 8 h. Ca-α-SiAlON:Eu2+ had high adsorption in the UV–visible spectral region. Two bands were observed in the emission spectrum centered at about 459 and 545 nm exited at 290nm. And two excitation bands located at about 297nm, 300-400nm were observed in the excitation spectrum with monitored at emission wavelength of 469nm or 550nm respectively. The morphology of the samples was examined via SEM, TEM. Ca/Eu co-doped α-SiAlON powders had hollow sphere morphology and it is composed of large numbers of very fine particles of around 30 to 70 nm in diameter. Elemental distribution was investigated using an EDS attached to a scanning electron microscopy (SEM). The sintered sample has a composition commonly seen for α-SiAlON.
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Authors: Li Li, Cheng Zhang, Dan Yu Jiang, Na Zhang, Cai Xia Li, Qiang Li
Abstract: Eu2+ doped b-SiAlON (z = 1, 3, 4) phosphor were synthesized by carbothermal reduction- nitridation (CRN) using precursors powder as materials. The precursors powder prepared by sol-gel method using the SiO2, AlCl3×6H2O, Eu(NO3)3, ammonia water, carbon powders as starting materials. The CRN reaction proceeded at 1380°C for 6 h in an N2 atmosphere. Eu2+ doped b-SiAlON (z = 1, 3, 4) had high adsorption in the UV-visible spectral region. While z = 1, one bands were observed in the emission spectrum centered at about 425 nm monitored at 282 nm. The excitation bands centered at about 282 nm. While z = 3, one bands were observed in the emission spectrum centered at about 425 nm monitored at 282 nm. The excitation bands centered at about 282 nm. While z = 3, the emission spectra exhibit one bands with maxima at about 419 nm under 280 nm excitation. The excitation bands centered at about 280 nm. While z = 4, the emission spectrum centered at about 419 nm monitored at 280 nm. The excitation bands centered at about 280 nm. In this work, luminescence properties of Eu2+ doped b-SiAlON (z = 1, 3, 4) are independent of z value. It is possible related to the low synthesis temperature.
320
Authors: Jing Meng, Dan Yu Jiang, Qiang Li
Abstract: Scintillators are ideal candidates used in detectors for X-ray ,γ-ray and high energy ray , and have been widely applied in nuclear medicine , high energy physics ,geologic survey , security inspection and material flaw detection. The high density of HfO2 is an attractive compound for host lattice activated by rare earth for applications as scintillating materials. This paper reported the synthesis of Eu3+ doped HfO2 nanopowders by chemical self-combustion method at low temperature. Analytical grade Eu(NO3)3 and high pure HfOCl2 were used as raw materials. The requisite amount of urea and glycine as the mixed fuel were added to the mixed solution. A little EDTA was used as a complexant. The mixed solution was dried at 200°C, and fired at 450°C. The powders synthesized by self-combustion were then calcined at 800°C to profit the crystal growth and improve the luminescent properties. XRD, TEM were employed to analyze the phase composition and the characteristics of as-obtained powders. The TEM images display typical nano-structured morphology of Eu3+ doped HfO2. Analysis of XRD indicates that Eu3+ doped HfO2 nanopowders are cubic phase. The excitation and emission spectra were analyzed by the fluorescence photometer. There are two peaks in emission spectra .One is at 595nm, and another is at 614nm. The luminescent properties also reveal the structure of cubic phase.
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Authors: Xiao Xu, Li Mei Cao, Dan Yu Jiang, Qiang Li
Abstract: The luminescent properties of SrAl2O4 based materials were studied systematically, which emit long persisting phosphorescence with high brightness and show greater chemical stability than the traditional ZnS:Cu,Co phosphor. In order to obtain the better dispersed powders, SrAl2O4:Eu2+, Dy3+ was synthesized by a dipping process. The as-received samples are yellow-green in color and display better dispersion than those synthesized by the co-deposition method. The optimized conditions of this dipping process were explored. The luminescent properties and the crystal structure were studied in detail.
381
Authors: Li Mei Cao, Wen Bo Bu, Chuan Ai Ren, Xiao Xu, Qiang Li
Abstract: Zn2SiO4:Mn2+ was synthesized via a dipping method. Stoichiometric high pure SiO2 was put into the solution of zinc nitrate and manganese nitrate. The mixture was milled while being heated until the water was vaporized completely. The as-received mixture was added into the ethanol, and dispersed well, then the mixture was milled and heated to remove the ethanol thoroughly by evaporation. The precursor were dried for several hours at 60°C, and annealed in a reducing atmosphere of active carbon at 1000°C for 4 h. As-prepared powders of Zn2SiO4:Mn2+ was tested by XRD and SEM. Its luminescent properties were characterized by excitation and emission spectra. The results are compared with those of Zn2SiO4:Mn2+ prepared by a general solid state reaction.
375
Authors: Jing Chu, Yu Lin Li, Bing Xu, Na Zhang, Qiang Li
Abstract: Niobium oxide thin films were successfully synthesized starting from niobate nanosheets. The microstructure of as-prepared nanosheets was observed by TEM. The morphology of niobate thin films was investigated by SEM. The phase structure was determined by XRD. The transmittance spectra of as-obtained niobium oxide thin films were measured, and the optical properties were studied. The influences of different thickness on optical properties were also analyzed. As-prepared niobium thin films were treated by being heated at different temperature. The effects of soaking temperature on the structure and optical properties of niobium oxide thin films were discussed in detail.
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Authors: Jin Feng Xia, Zhan Lian Liu, Qiang Li, Dan Yu Jiang
Abstract: It is important to accurately determine the MgO content in MgO-ZrO2 powders. The measurement method for MgO content in MgO-ZrO2 powders was studied. Afterwards, the prepared powders were characterized by XRD and SEM technologies. The results show that the MgO-ZrO2 powders obtain different solid-solubility, crystal structure and particle size at different magnesia molar concentrations and different calcinations temperature.
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