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Chinese Physics B 2014年第12期23卷 390-397页

作者：周树兰赵显江向平韩晓东 department of Material Science and Engineering Jingdezhen Ceramics Institute State Key Laboratory of Crystal Material Institute of Crystal Material Shandong University

The electronic structures, Born effective charges（BECs）, and full phonon dispersions of cubic, tetragonal, orthorhombic, and rhombohedral K0.5Na0.5Nb O3 are investigated by the first principles method based on density functional *** hybridized states of Nb 4d and O 2p states are observed in the valence band, showing the formation of a strong Nb–O covalent bond which should be responsible for the displacement of Nb and O atoms. The abnormally large BECs of Nb and O indicate the possibility of phase instability induced by the off-center displacement of Nb and O atoms. The phonon dispersions reveal that the ferroelectric instability of K0.5Na0.5Nb O3 is dominated by Nb and O displacements with significant Na characteristics. In addition to the ferroelectric instability, there is also rotational instability coming from the oxygen octahedra rotation around one axis. Moreover, the Γ phonon properties of orthorhombic KNb O3, Na Nb O3, and K0.5Na0.5Nb O3 are also studied in detail.

关键词： Born effective charge phonon dispersion density functional theory(DFT) phase instability of K0.5Na0.5NbO3

Structural and electrical transport properties of a rare earth double perovskite oxide:Ba_2ErNbO_6

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Journal of Rare Earths 2014年第4期32卷 334-342页

作者： Rajesh Mukherjee Binita Ghosh Sujoy Saha Chandrahas Bharti T.P.Sinha department of Physics Ramananda College department of Physics Bose Institute Sensor and Actuator Division CSIR-Central Glass and Ceramic Research Institute

The double perovskite oxide barium erbium niobate, Ba2ErNbO6 （BEN） was synthesized by solid state reaction technique. Rietveld refinement of the X-ray diffraction pattern of the sample showed cubic （Fm3m） phase at room temperature. Fourier trans-form infrared spectrum showed two primary phonon modes of the sample at around 387 and 600 cm-1. Raman spectrum of the sam-ple taken at 488 nm excitation wavelength showed four primary strong peaks at 106, 382, 747 and 814 cm-1. Lorentzian lines with 10 bands were used to fit the Raman spectrum. A group theoretical study was performed to assign all the Raman modes. Impedance spectroscopy was applied to investigate the ac electrical conductivity of BEN in a temperature range from 303 to 673 K and in a fre-quency range from 100 Hz-1 MHz. The dielectric relaxation mechanism was discussed in the frame work of permittivity, conduc-tivity, modulus and impedance formalisms. The complex plane plot of the impedance data was modeled by an equivalent circuit con-sisting of two serially connected R-CPE units, （one for the grain and the other for the grain boundary）, each containing a resistor （R） and a constant phase element （CPE）. The R-CPE units were used to incorporate the non-ideal character of the polarization phenome-non instead of an ideal capacitive behaviour. The relaxation time corresponding to dielectric loss was found to obey the Arrhenius law with activation energy of 0.85 eV. The frequency dependent conductivity spectra followed the Jonscher power law. The Cole-Cole model was used to investigate the dielectric relaxation mechanism in the sample.

关键词： perovskites Rietveld refinement Raman spectroscopy impedance spectroscopy rare earths

Cofiring behavior of NiCuZn ferrite/PMN ferroelectrics di-layer composites

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中国有色金属学会会刊：英文版 2005年第2期15卷 225-228页

作者：缪春林周济岳振星李龙土 State Key Laboratory of New ceramics and Fine Processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

The cofiring compatibility between ferrite and relaxor ferroelectrics materials is the key issue in the production of multilayer chip LC filters. The cofiring behavior, interfacial microstructure and diffusion of di-layer composites of NiCuZn ferrite/PMN relaxor ferroelectrics are studied. In order to analyze the matching condition of thermodynamic properties between ferrite and relaxor ferroelectric ceramics, TMA is performed on PMN ferroelectrics and NiCuZn ferrite with certain percentage of Bi2O3, respectively. EDS results demonstrate that serious element diffusions exist at the interface, which is in accordance with the phase analysis based on XRD patterns.

关键词：纤维化性质镍铜锌铁素体 PMN铁电复合材料多层界面

LiMn_(2)O_(4) Microspheres:Synthesis,Characterization and Use As a Cathode in Lithium Ion Batteries

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Nano Research 2010年第10期3卷 733-737页

作者： Xiaoling Xiao Jun Lu Yadong Li department of Chemistry and State Key Laboratory of New ceramics and Fine Processing Tsinghua UniversityBeijing 100084China

Solid and hollow microspheres of LiMn_(2)O_(4) have been synthesized by lithiating MnCO_(3) solid microspheres and MnO_(2) hollow microspheres,*** LiMn_(2)O_(4) solid microspheres and hollow microspheres had a similar size of about 1.5μm,and the shell thickness of the hollow microspheres was only 100 *** used as a cathode material in lithium ion batteries,the hollow microspheres exhibited better rate capability than the solid ***,the tap density of the LiMn_(2)O_(4) solid microspheres(1.0 g/cm^(3))was about four times that of the hollow microspheres(0.27 g/cm^(3)).The results show that controlling the particle size of LiMn_(2)O_(4) is very important in terms of its practical application as a cathode material,and LiMn_(2)O_(4) with moderate particle size may afford acceptable values of both rate capability and tap density.

关键词： Cathode LiMn_(2)O_(4)microspheres tap density rate capability particle size

3D printed titanium scaffolds with ordered TiO2 nanotubular surface and mesoporous bioactive glass for bone repair

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Progress in Natural Science:Materials International 2020年第4期30卷 502-509页

作者： Pengyu Zhao Yaqin Liu Tian Li Yanling Zhou Sander Leeflang Lei Chen Chengtie Wu Jie Zhou Zhiguang Huan State Key Laboratory of High Performance ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences department of Biomechanical Engineering Delft University of Technology

Titanium alloy scaffolds have recently gained substantial interest for the treatment of critical-size bone defect,particularly along with the maturity of the 3D printing technology that is capable of turning scaffold design ideas into real implants. As titanium alloys lack surface osteogenic activity, for improved biological performance of such scaffolds, surface modification is necessary. Various coating materials and coating methods have been explored. In this study, we developed a unique surface modification method to provide the surface of 3D printed titanium scaffolds with nano-sized structure and bioactive agent. Uniform, ordered TiO2nanotube arrays were formed by applying two-step anodization, and then mesoporous bioactive glass（MBG） was loaded into nanotubes. The results of in vitro immersion testing showed that bioactive ions, i.e., Si and Ca ions, could be steadily and continuously released from MBG into basal medium. The assessment of the responses of h BMSCs confirmed that the surface-modified scaffolds supported the adhesion and proliferation of h BMSCs, indicating good surface cytocompatibility. The developed method of combining surface nanostructure and bioactive agent could be used as a new strategy to improve the osteogenic activity of 3D printed titanium alloy scaffolds.

关键词： Titanium Scaffold Mesoporous bioactive glass Nanotube Anodization

Preparation, Morphology Transformation and Magnetic Behavior of Co3O4 Nano-Leaves

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Chinese Physics Letters 2010年第12期27卷 196-198页

作者：孟令镕陈伟孟陈晋平周和平彭卿 State Key Laboratory of New ceramics and Fine Processing Department of Chemistry and Department of Materials Science and Engineering Tsinghua University Beijing 100084 department of Physics Peking University Beijing 100871

A series of cubic phase Co3O4 nano-leaves were prepared via a combined approach of solution reaction and calcination. According to x-ray diffraction and electron microscopy, we find that the Co3 04 grain size increases with calcination temperature. This can induce many gaps in the products. M-T and M-H magnetization measurements reveal the typical antiferromagnetie behavior of nano-leaves. The effective moments of the samples prepared at 300, 400 and 500℃ are 5.6, 5.8 and 5.7μB per formula unit （FU）, respectively, larger than the bulk value of 4.14 μB/FU.

关键词： Leaves Microscopy Measurement

Development of Deformation-Semisolid-Casting (D-SSC) Process and Applications to Some Aluminum Alloys

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Journal of Materials Science & Technology 2008年第1期24卷 12-16页

作者： Tatsuo Sato department of Metallurgy and ceramics Science Tokyo Institute of Technology 2-12-1O-okayamaMeguro-kuTokyoJapan

Recent advances in the semisolid casting technologies are introduced for aluminum *** advantages of the rheocast and thixocast methods to fabricate alloys with refined spheroidizedα-Al particles are described. The deformation-semisolid-casting （D-SSC） process developed by the author＇s group is *** D-SSC process is extremely effective to produce microstructures of refined intermetallic compound particles as well as the spheroidizedα-Al particles in the Al-Si based alloys containing highly concentrated *** the D-SSC processed Al-Si-Cu alloy high elongation of about 20% was achieved even contained concentrated impurity of *** D-SSC process is also useful to produce wrought aluminum alloys with microstructures of refinedα-Al particles.

关键词： Semisolid casting Rheocast Thixocast Aluminum alloys Intermetallic compound

An HREM Study on Structural Defects in Y-deficient YBCO Superconductor

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Chinese Science Bulletin 1994年第16期39卷 1343-1346页

作者：刘茜温树林严东生方明虎焦正宽张其瑞 The State Key Laboratory on High Performance ceramics and Superfine Microstructure Shanghai Institute of Ceramics Academia Sinica Shanghai 200050 PRC department of Physics Zhejiang University Hangzhou 310027 PRC

The great practical application possibilities of high T_c superconductors make Y-123 oxides an attractive topic of research. The wide investigation on the 123 family original compositions has revealed the influence of substitution and stoichiometry on superconductivity, owing to the chemical disturbances in the nanometre scale or even at the atomic level to render a local structure change in A,B, or O sites in the perovskite framework. All 123 family members (T_c≈90 K) reported hitherto possess an orthorhombic crystal structure, with Cu-O chains and Cu-O planes being responsible for the superconducting characteristics.

关键词： Y1xBa2Cu3O7-y structural defect pinning.

Antibacterial Activity of Silicate Bioceramics

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Journal of Wuhan University of Technology(Materials Science) 2011年第2期26卷 227-231页

作者：扈盛常江 department of Physical Education Huazhong Normal University Biomaterials and Tissue Engineering Research Center Shanghai Institute of Ceramics

Four kinds of pure silicate ceramic particles,CaSiO3,Ca3SiO5,bredigite and akermanite were prepared and their bactericidal effects were systematically *** phase compositions of these silicate ceramics were characterized by *** ionic concentration measurement revealed that the Calcium （Ca） ion concentration were relatively higher in Ca3SiO5 and bredigite,and much lower in CaSiO3 and ***,the pH values of the four silicate ceramics extracts showed a positive correlation with the particle ***,by decreasing the particle size,higher Ca ion concentrations can be achieved,leading to the increase of aqueous pH value as *** summary,all of the four silicate ceramics tested in our study showed antibacterial effect in a dose-dependent ***,the order of their antibacterial activity against *** from strong to weak is Ca3SiO5,bredigite,CaSiO3 and akermanite.

关键词： silicate ceramics antibacterial activity specific surface area aqueous pH ionic concentration

Effects of silicon addition on optical properties of mould flux with iron oxide and estimation of apparent thermal conductivity of flux

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Journal of Iron and Steel Research International 2019年第4期26卷 365-373页

作者： Rie Endo Yo Kan Takashi Watanabe Miyuki Hayashi Masahiro Susa department of Materials Science and Engineering Tokyo Institute of TechnologyTokyo 152-8552Japan department of Metallurgy and ceramics Science Tokyo Institute of TechnologyTokyo 152-8552Japan

Mould flux with high absorptivity had been obtained in the reduction process of mould flux by *** further utilisation of the mould flux with high absorptivity,the effect of silicon addition on the optical property has been *** synthesised mould flux powder with iron oxide was melted with the addition of silicon powder at 1703 K followed by quenching,thus forming a glassy *** 5-30-min reduction,the samples exhibited black opaque ***,the samples that were reduced for 45-60 min had a bluish grey *** iron-based particles dispersed in the samples were micrometre order in *** determine the effect of iron particles on the optical properties of the sample,extinction,scattering and absorption efficiencies were calculated according to Mie *** showed that both scattering on the iron particle and absorption by iron effectively increase the extinction efficiency in the mould ***,the silicon particle in the flux has large scattering *** black opaque colour is contributed by the existence of silicon and iron *** apparent thermal conductivity was calculated for the solid *** also indicated that the entire glassy mould flux would effectively work for mild cooling in a continuous casting process owing to high absorptivity and small thermal conductivity.

关键词： Mould flux Reduction Iron oxide Thermal conductivity Optical property