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Fibre Optical Parametric Amplification in Defect Bragg Fibres with Zero Dispersion Slow Light Effect

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Chinese Physics Letters 2008年第5期25卷 1713-1716页

作者：肖礼张巍黄翊东彭江得赵红杨克武 department of Electronic Engineering Tsinghua University Beijing 100084 Beijing glass Research-Institute Beijing 100-062

Nonlinearity enhancement by slow light effect and strong light confinement in defect Bragg fibres is demonstrated and anMysed in applications of fibre optical parametric amplifiers. Broadband low group velocity and zero dispersion as well as the strong light confinement by band gap enhances the nonlinear coefficient up to more than one order than the conventional high nonlinear fibres. Moreover, the zero dispersion wavelength of coupled core mode can be designed arbitrarily, under which the phase-matching bandwidth of the nonlinear process can be extended.

关键词： supernova explosion proto-neutron star shock wave

Structure evolution and thermal stability of La_2O_3-doped mullite fibers via sol-gel method

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Journal of Rare Earths 2012年第2期30卷 175-180页

作者：王炜翁端吴晓东 State Key Laboratory of New ceramics&Fine Process Department of Materials Science and EngineeringTsinghua University The Second Artillery NCO Academy of PLA

The lanthana-doped mullite fibers were prepared via a sol-gel method from the aluminum isopropoxide-aluminum nitrate-tetraethyl orthosilicate system. The structure evolution and thermal stability of the mullite fibers were investigated by means of X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectroscopy, differential scanning calorimetry （DSC）, scanning electron microscopy （SEM） and trans-mission electron microscopy （TEM）. The results showed that the fibers obtained after calcination at 1000℃ was in the form of Al2O3-rich mullite, which tended to transform to stoichiometric mullite with the lanthana content increasing. The lattice parameter a exhibited a decline trend with the lanthana content increasing, while b showed an upward tendency. Correspondingly, the redshift of Si-O-Si bond from 1255 to 1245 cm-1 was observed. The grain growth was inhibited for the doped fibers, among which the 5% La2O3-doped sample presented a mini-mum crystallite size （17.2 nm） after calcination at 1000 ℃ for 1 h.

关键词： mullite fibers lanthana doping phase transformation grain growth rare earths

Magnetoelectric and converse magnetoelectric responses in Tb_xDy_(1-x)Fe_(2-y) alloy & Pb(Mg_(1/3)Nb_(2/3))_(1-x)Ti_xO_3 crystal laminated composites

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Chinese Science Bulletin 2008年第14期53卷 2129-2134页

作者： JIA YanMin LUO HaoSu OR Siu Wing WANG YaoJin CHAN Helen L W State Key Laboratory of High Performance ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 201800 China department of Applied Physics The Hong Kong Polytechnic University Hong Kong China

Measured results of magnetoelectric (ME) and converse magnetoelectric (CME) effects of TbxDy1-xFe2-y/ Pb(Mg1/3Nb2/3)(1-x)TixO3/TbxDy1-xFe2-y (TD/PMNT/TD) and PMNT/TD/PMNT laminated composites are pre- sented. ME effect was determined by measuring laminate voltage output under a Helmholtz-gener- ated AC field biased by a DC field (0―1 kOe) (1 Oe = 79.58 A/m). The CME effect was measured by re- cording the voltage induced in a solenoid encompassing the ME sample while exposed to a DC bias field and PMNT layer driven by a 10 V AC source. The ME and CME responses in the two laminated structure are linear. The highest values of ME coefficients in TD/PMNT/TD and PMNT/TD/PMNT com- posites are 384 mV/Oe and 158 mV/Oe, respectively, while the highest values of CME coefficients in the two composites are 118 mG/V and 162 mG/V (1 G=10-4 T), respectively.

关键词：磁电效应压电性复合材料合金晶体结构

Phase Diagram Prediction of the Al_2O_3-SiO_2-La_2O_3 System

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Journal of Materials Science & Technology 1999年第5期15卷 439-443页

作者： Lin LI and Zhujun TANG(department of Materials Science & Engineering, Shanghai University, Shanghai 200072, China) To whom correspondence should be addressedE-mail: liling@*** Weiying SUN and Peiling WANG(Shanghai Institute of ceramics, Chi department of Materials Science and Engineering Shanghai University Shanghai 200072 China Shanghai Institute of ceramics Chinese Academy of Sciences Shanghai 200050 China

Rare earth oxide systems Al2O3-La2O3 and SiO2-La2O3 were thermodynamically assessed and optimized with the substitution model. The obtained model parameters and Gibbs free energy of tine compounds and pure components ... 详细信息

关键词： SiO Al La

An abnormal displacement change during holding period in nanoindentation tests on zirconia dental ceramic

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Journal of Advanced ceramics 2016年第2期5卷 153-158页

作者： Lixian ZHANG Longquan SHAO Lei LI Danyu JIANG department of Prosthodontics the First Hospital of Yunnan Province Kunming 650000 China department of Stomatology Nanfang Hospital Southern Medical University Guangzhou 510515 China Analysis and Testing Center for Inorganic Materials the State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Shanghai 200050 China

An abnormal displacement change observed during the holding period in nanoindentation tests on a zirconia dental ceramic was reported in this paper. It was found that, at the initial stage of the holding period, the measured displacement versus time curves were similar in shape with the typical indentation creep curve reported in previous studies. As the holding lasted for long time, however, an evident reduction in displacement was observed for tests with high loading rate, implying that another unknown process, which might result in a decrease in displacement, would co-exist with creep during holding period. Elastic recovery was suggested to be one of the possible sources for such a displacement reduction. An empirical method was also proposed to eliminate the effect of this displacement reduction on the determination of hardness and Young's modulus.

关键词： zirconia nanoindentation displacement elastic recovery

Characterization of low-purity clays for geopolymer binder formulation

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International Journal of Minerals,Metallurgy and Materials 2014年第6期21卷 609-619页

作者： Nasser Y.Mostafa Q.Mohsen A.El-maghraby Materials and Corrosion Lab (MCL) Department of Chemistry Faculty of Science Taif University department of Chemistry Faculty of Science Suez Canal University Refractory & ceramics department National Research CenterDokki 12622 Cairo Egypt

The production of geopolymer binders from low-purity clays was investigated. Three low-purity clays were calcined at 750℃ for 4 h. The calcined clays were chemically activated by the alkaline solutions of NaOH and Na2SiO3. The compressive strength was measured as a function of curing time at room temperature and 85℃. The results were compared with those of a pure kaolin sample. An amorphous aluminosilicate polymer was formed in all binders at both processing temperatures. The results show that, the mechanical properties depend on the type and amount of active aluminum silicates in the starting clay material, the impurities, and the processing temperature.

关键词： geopolymers microstructure X-ray diffraction compressive strength clay

Effect of SiO_2 addition on the dielectric properties and microstructure of BaTiO_3-based ceramics in reducing sintering

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International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 124-127页

作者： Ying-chieh Lee Wei-hua Lu Su-hei Wang Chai-wei Lin department of Material Engineering Pingtung University of Technology ＆ Science China Taipei Electronic ceramics Research Center Yageo Kaohsiung 811 China Taipei

The effect of SiO2 doping on the sintering behavior, microstructure, and dielectric properties of BaTiO3-based ceramics has been investigated. Silica was added to the BaTiO3-based powder prepared by the solid state method with 0.075mol%, 0.15mol%, and 0.3mol%, respectively. The SiO2-doped BaTiO3-based ceramic with high density and uniform grain size were obtained, which were sintered in reducing atmosphere. A scanning electron microscope, X-ray diffraction, and LCR meter were used to determine the microstructure as well as the dielectric properties. SiO2 can form a liquid phase belonging to the ternary system of BaO-TiO2-SiO2, leading to the formation of BaTiO3 ceramics with high density at a lower sintering temperature. The SiO2-doped BaTiO3-based ceramics can be sintered to a theoretical density higher than 95% at 1220℃ with a soaking time of 2 h. The dielectric constants of the sample with 0.15mol% SiO2 addition sintered at 1220℃ is about 9000. Doping with a small amount of silica can improve the sintering and dielectric properties of BaTiO3-based ceramics.

关键词： barium titanate multilayer ceramic capacitor (MLCC) reducing atmosphere dielectric properties

Improvement on the Luminescence Property of Y, Sb Co-doped PbWO_4 Single Crystal

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High Technology Letters 2001年第2期7卷 87-88页

作者：杨春晖 Shi Pengfei Chen Gang department of Applied Chemistry Harbin Institute of Tecnology Beijing glass Research Institute

The effect of Y and Sb co-doping on the luminescence property of PbWO 4 crystals has been investigated. Compared with undoped PbWO4, the transmittance and emission peak intensity of Y∶Sb∶PbWO 4 crystals were obviously improved. In addition, its transmittance cutoff wavelength and emission peak shifted to the shorter one. The mechanism of effect of Y and Sb on the transmittance spectra was briefly discussed. The light yield of Y∶Sb∶PbWO 4 crystals was 25p.e./MeV, which was two times of that of undoped PbWO 4. Our experiments showed that Y and Sb co-doping was a selectable method to improve the luminescence property of PbWO 4.

关键词： Y∶Sb∶PbWO4 crystal Transmittance Exicted-emission spectra Light yield

Facile Synthesis of Long,Straight and Uniform Copper Nanowires via a Solvothermal Method

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稀有金属材料与工程 2006年第A3期35卷 644-645页

作者： Chunfu Lin Hong Lin Ning Wang Xing Zhang Jun Yang Jianbo Li Xiaozhan Yang State Key Lab of New ceramics ＆ Fine Processing Department of Materials Science ＆ Engineering Tsinghua University Beijing 100084 China

Copper nanowires were facilely prepared via a solvothermal *** this method,cetyitrimethylammonium bromide (CTAB) was used as a soft template,copper nitrate was an inorganic precursor,and absolute ethanol served as a reducing agent as well as a solvent.X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the as-prepared copper *** as-prepared copper nanowires are fairly uniform and *** majority of them are longer than 100μm and some even longer than 200μ***,most nanowires are quite *** addition, The mechanism of the growth process of copper nanowires was discussed.

关键词： copper nanowires solvothermal method template