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Electrochemical performance of a nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material for lithium-ion batteries under different cut-off voltages

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International Journal of Minerals,Metallurgy and Materials 2017年第3期24卷 342-351页

作者： Kai-lin Cheng Dao-bin Mu Bo-rong Wu Lei Wang Ying Jiang Rui Wang Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081China Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100081 China

A spherical-like Ni0.6Co0.2Mn0.2(OH)2precursor was tuned homogeneously to synthesize LiNi0.6Co0.2Mn0.2O2as a cathode material for lithium-ion batteries. The effects of calcination temperature on the crystal structure, morphology, and the electrochemical performance of the as-prepared LiNi0.6Co0.2Mn0.2O2were investigated in detail. The as-prepared material was characterized by x-ray diffraction, scanning electron microscopy, laser particle size analysis, charge–discharge tests, and cyclic voltammetry measurements. The results show that the spherical-like LiNi0.6Co0.2Mn0.2O2material obtained by calcination at 900°C displayed the most significant layered structure among samples calcined at various temperatures, with a particle size of approximately 10 μm. It delivered an initial discharge capacity of 189.2 mAh•g−1at 0.2C with a capacity retention of 94.0% after 100 cycles between 2.7 and 4.3 V. The as-prepared cathode material also exhibited good rate performance, with a discharge capacity of 119.6 mAh•g−1at 5C. Furthermore, within the cut-off voltage ranges from 2.7 to 4.3, 4.4, and 4.5 V, the initial discharge capacities of the calcined samples were 170.7, 180.9, and 192.8 mAh•g−1, respectively, at a rate of 1C. The corresponding retentions were 86.8%, 80.3%, and 74.4% after 200 cycles, respectively. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

关键词： Calcination Cathodes Cobalt Crystal structure Cyclic voltammetry Electric batteries Electric discharges Electrochemical properties Electrodes Ions Lithium Lithium alloys Lithium compounds Manganese Nickel Particle size Particle size analysis Scanning electron microscopy Secondary batteries x ray diffraction

Enhanced near infrared emission in water-soluble NdF_3 nanocrystals by Ba^(2+) doping

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Chinese Optics Letters 2012年第2期10卷 68-70页

作者：樊婷张勤远姜中宏 MOE Key Laboratory of Special Functional Materials and Institute of Optical Communication Materials South China University of Technology

A simple and efficient method for the synthesis of water-soluble NdF3 and NdF3：Ba^2＋ nanocrystals under hydrothermal conditions is established. The method involves the coating of the nanocrystals with a layer of hydrophilic polymer polyvinylpyrrolidone （PVP）. The as-prepared products are characterized by powder x-ray diffraction, field emission scanning electronic microscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy. The PVP coating transforms the nanocrystals into a biocompatible material and improves the fluorescence intensity of NdF3 in the near infrared （NIR） region. The morphology of the nanoparticles changes, whereas the fluorescence intensity of NdF3 in the NIR region increases when a small amount of Ba^2＋ is doped into the NdF3/PVP nanoparticles.

关键词： Biological materials Coatings Fluorescence Fourier transform infrared spectroscopy Nanocrystals Nanoparticles Photoluminescence spectroscopy x ray diffraction

Effects of Rapid Cycle Annealing Temperature on TbFe Magnetostrictive Films

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Chinese Physics Letters 2004年第8期21卷 1624-1627页

作者：蒋洪川张金平张万里彭斌张文旭杨仕清张怀武 CollegeofMicroelectronicsandSolidStateElectronics UniversityofElectronicScienceandTechnologyofChinaChengdu610054

The effects of annealing temperature on TbFe films prepared by dc magnetron sputtering were discussed. x-ray diffraction patterns indicate that these polycrystalline films consisting mainly of α-Fe and TbFe2 lave phase with grain sizes less than 25nm can be obtained by a rapid cycle annealing process. Grain sizes can be controlled by varying annealing temperatures. Film hysteresis loop studies show that annealing treatment can improve TbFe film in-plane soft magnetic performances. Magnetic domain structures explored by a magnetic force microscopy show that in the as-deposited films, maze domain structures exist, hence it possesses perpendicular anisotropy and larger anisotropic constant Ku. No domains are observed when annealing temperature is lower than 400 degrees C. However, maze domain structures appear again when annealing temperature is higher than 400 degrees C. Two maxima of magnetostrictive coefficients are obtained at annealing temperatures of 300 degrees C and 500 degrees C in the presence of a 40kA.m−1 external magnetic field.

关键词： x ray diffraction

Growth of a-Plane InN Film and Its THz Emission

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Chinese Physics Letters 2014年第7期31卷 160-163页

作者：王光兵赵国忠郑显通王平陈广荣新王新强 State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of Physics Peking University Beijing 100871 Collaborative Innovation Center of Quantum Matter Beijing 100871 Department of Physics Capital Normal University Beijing 100048

We report the growth of a-plane InN on an r-plane sapphire substrate by plasma-assisted molecular-beam epitaxy. It is found that the a-plane InN is successfully grown by using a CaN buffer layer, which has been confirmed by reflection high-energy electron diffraction, x-ray diffraction and Raman scattering measurements. The Hall effect measurement shows that the electron mobility of the as-grown a-plane InN is about 406 cm^2/V·s with a residual electron concentration of 5.7 × 10^18 cm^-3. THz emission from the a-plane InN film is also studied, where it is found that the emission amplitude is inversely proportional to the conductivity.

关键词： x ray diffraction

Small d-spacing WSi_2/Si multilayers for x-ray monochromators

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Chinese Optics Letters 2012年第12期10卷 87-90页

作者：黄秋实李浩川朱京涛王占山唐永建 Key Laboratory of Advanced Micro-structural Materials Ministry of EducationInstitute of Precision Optical EngineeringPhysics DepartmentTongji University Research Center of Laser Fusion Chinese Academy of Engineering Physics

A WSi2/Si multilayer, with 300 bi-layers and a 2.18-nm d-spacing, is designed for x-ray monochroma- tor application. The nmltilayer is deposited using direct current magnetron sputtering technology. The reflectivity of the 1st-order Bragg peak measured at E = 8.05 keV is 38%, and the angular resolution （△θ/θ） is less than 1.0%. Fitting results of the reflectivity curve indicate a layer thickness drift of 1.6%, mainly accounting for the broadening of the Bragg peaks. The layer morphology is further characterized by transmission electron microscopy, and a well-ordered multilayer structure with sharp interfaces is observed from the substrate to the surface. The material combination of WSi2/Si is a promising candidate for the fabrication of a high-resolution nmltilayer monochromator in the hard x-ray region.

关键词： Curve fitting Interfaces (materials) Monochromators Reflection Silicon Transmission electron microscopy x ray diffraction x rays

Growth and optical properties of Cr^(3+)-doped CdWO_4 single crystals

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Chinese Optics Letters 2012年第4期10卷 51-54页

作者：万云涛胡皓阳夏海平张约品江浩川陈红兵 Key laboratory of Photo-Electronic Materials Ningbo University Faculty of Material Science and Chemical Engineering Ningbo University

A high-quality Cr 3＋：CdWO4 single crystal at a size of approximatelyΦ25×80 mm is grown using the Bridgman method with CdO,WO3,and Cr2O3 as raw materials and their molar ratio of 100：100：*** temperature gradient of solid-liquid interface at growth is approximately 50？C/cm and the growth rate is 0.05 mm/*** x-ray diffraction（xRD）,absorption,excitation,and emission spectra of different parts of the as-grown and O2-annealed crystals are *** strong broad optical absorption bands of about 472 and 708 nm are observed,and they are associated with the transitions 4 A2→ 4 T1 and 4 A2→ 4 *** weak 4 T2→ 2 E transition（the R-line）at 632 nm is also *** crystal-field parameter Dq and the Racah parameters B and C are estimated to be 1 412.4,776.8,and 3 427.6 cm？ 1,respectively,according to the absorption spectra and crystal-splitting theory.A broadband fluorescence at about 1 000 nm due to 4 T2→ 4 A2 transition is produced by exciting the samples at 675 *** being annealed in an O2 atmosphere,the crystals become more transparent,while the effective light absorption of Cr 3＋ ions is evidently enhanced and the emission intensity is also strengthened due to the reduction of oxygen vacancies in the CdWO4 crystal after annealing.

关键词： Annealing Cadmium compounds Emission spectroscopy Light absorption Optical properties Single crystals x ray diffraction

Optical property of nanocomposite of mesoporous silica thin films incorporated with gold nanoparticles

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Chinese Optics Letters 2011年第3期9卷 69-72页

作者：方靖岳张学骜秦石乔常胜利 College of Optoelectric Science and Technology National University of Defense Technology College of Science National University of Defense Technology

Amino-functionalized mesoporous silica thin films （MTFs） are produced using surface active agent F127,and then gold nanoparticles are introduced into the pore channels to prepare the Au/SiO 2 *** assembling the gold,the amino-functionalized MTF undergoes some shrinkage but remains a periodic structure as demonstrated by x-ray diffraction （xRD） *** nanocomposite shows an acute characteristic diffraction peak assigned to （111） plane of the face-centered-cubic structure of gold,indicating that gold nanoparticles crystallize well and grow in a preferred orientation in the pore *** surface plasma resonance （SPR） absorption peak near 570 nm undergoes a red-shift accompanied by a strengthening of intensity when HAuCl 4 is used to react with the amino groups on the internal pore surfaces for 4,6,and 8 *** simulative results are consistent with the experimental ones shows that the absorption property of the Au/SiO 2 nanocomposite is influenced by the dipping time,which affects the size and volume fraction of embedded gold nanoparticles.

关键词： Absorption diffraction Gold Mesoporous materials Nanocomposites Nanoparticles Optical properties Silica Surface active agents Thin films x ray diffraction

Mechanical and electrical properties of Pd-Ru system doped with Zr, Mo, Y

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Rare Metals 2012年第5期31卷 434-437页

作者： HU Jieqiong xIE Ming YANG Youcai ZHANG Jiming LIU Manmen State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals Kunming Institute of Precious Metals Kunming 650106 China

The effect of Zr, Mo, Y dopant on mechanical and electrical properties of Pd-Ru binary alloy was investigated in this work. The alloys were prepared in a vacuum high-frequency melting furnace. x-ray diffraction and metallographic microscope were employed to detect the microstructures of alloys. Electric bridge and eddy current conductive instrument were employed to test the electrical resistivity, and the mechanical properties of alloys were tested by AG-x100KN-type tensile testing machine. The results show that adding rare metal elements into Pd-Ru system could refine the structure effectively and increase the melting point, density, tensile strength, and hardness of alloy, but the elongation and electrical conductivity of alloy decrease. © The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2012.

关键词： Alloys Bridge circuits Doping (additives) Eddy current testing Electric conductivity Materials testing apparatus Mechanical properties Molybdenum Palladium Solid solutions Tensile testing x ray diffraction Zirconium

Preparation and photoluminescence of TiO_2/PS composite system

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Chinese Optics Letters 2010年第6期8卷 618-620页

作者：吕小毅侯军伟向梅贾振红钟福如 School of Electronic and Information Engineering Xi'an Jiaotong University School of Materials Science and Engineering Tongji University School of Chemistry and Chemical Engineering Xinjiang University College of Information Science and Engineering Xinjiang University

A TiO2/porous silicon(PS) composite system is prepared by chemical vapor *** crystal form with anatase phase of the samples is evaluated by x-ray diffraction and ultraviolet-visible(UV-vis) absorbance spectra,and the morphology with microsphere of TiO2particles is characterized by scanning electron *** composite system formed by this technique gives a broad blue luminescence and the mechanism of photoluminescence with TiO2/PS is also discussed.

关键词： Photoluminescence Porous silicon Titanium dioxide x ray diffraction