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Recent progress in single chip white light-emitting diodes with the InGaN underlying layer

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 445-448页

作者： WANG XiaoLi, WANG XiaoHui, JIA HaiQiang, XING ZhiGang & CHEN Hong beijing National Laboratory of condensed {2., institute of physics, chinese academy of sciences, beijing 100080, china beijing National Laboratory of condensed {2. Institute of Physics Chinese Academy of Sciences Beijing China

Tremendous progress has been achieved in white light-emitting diodes (LEDs). To further improve the quality of white light and simplify the fabrication process, a single chip white-light LED with the InGaN underlying layer (UL) was studied and fabricated. The turn-on voltage of this type of LED was 2.7 V, and the spectrum at a forward bias current of 2. mA was comprised of blue (443 nm) and yellow (563 nm) lights. The intensity ratio of blue to yellow light was almost constant with the in- creasing injection current in a certain scope, most important for the solid state illumination. The useful life test showed the light output level remained at a 90% light output level at the driving current of 40 mA after 300 h, meanwhile, the UV and blue LEDs combined with phosphor reached a 2.% value after 144 h within 300 h.

关键词： GaN InGaN white light LED MOCVD

Containerless solidification of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(2..5) glass-forming alloy in drop tube

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chinese Science Bulletin 2002年第20期47卷 1700-1703页

作者： LI Gong, SUN Liling & WANG WenkuiCollege of Material sciences and Engineering, Yanshan University, Qinhuangdao 066004, china {2. for condensed matter physics, institute of physics, chinese academy of sciences, beijing 100080, china National Microgravit Coll. of Mat. Sci. and Engineering Yanshan University Qinhuangdao 066004 China center for condensed {2. physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China National Microgravity Laboratory Chinese Academy of Sciences Beijing 100080 China

Droplets of Zr41Ti14Cu12.5Ni10Be2..5 glass forming alloys with different sizes are solidified in a drop tube containerless processing. Glass transition behavior, crystallization kinetics, and the phase evolution during annealing of the Zr41Ti14Cu12.5Ni10Be2..5 glassy spheres are investigated. The experimental results indicate that the apparent activation energy of the glass transition (Eg=435.5 kJ/mol), and the activation energy of the main crystallization reaction (Ep1 = 2.9.6 kJ/mol) are obviously different from those of bulk glass samples prepared by water quenched (Eg=559.1 kJ/mol and Ep1=192.5 kJ/mol). The difference is discussed in the view point of the atomic configuration of the liquid state of the metallic glass and nucleation mechanism.

关键词： ZrTiCuNiBe alloy containerless processing activation energy drop tube.

A 3.9 V polyanion-type cathode material for Li-ion batteries

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Progress in Natural Science:Materials International 2011年第3期21卷 211-215页

作者： Lei LIU,Bin ZHANG,Xue-jie HUANG beijing National Laboratory for condensed {2. physics, institute of physics,chinese academy of sciences,beijing,100190,china beijing National Laboratory for condensed {2. physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China

Monoclinic phase LiFeSO4F was synthesized by a simple fast solid state reaction from the mixture of FeSO4·7H2. and LiF pulverized by high energy ball milling.m-LiFeSO4F was confirmed by GITT measurement to be a 3.9 V polyanion-type cathode materials for Li-ion *** electrochemical activity can be enhanced by addition of carbon.A discharge capacity of 105 mA·h/g (70%of theoretical value) was achieved for a m-LiFeSO4F/CNT *** separation behavior during lithium extraction and insertion was observed by ex-situ XRD test.

关键词： LiFeSO4F polyanion cathode Li-ion battery

Magnetic Field Effects on Quantum-Dot Spin Valves

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Communications in Theoretical physics 2009年第3期51卷 555-562页

作者： GAO Jin-Hua,~1 SUN Qing-Feng,~1 and XIE Xin-Cheng~(1,2.1 beijing National Lab for condensed {2. physics and institute of physics, chinese academy of sciences,beijing 100080, china2.Department of physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA beijing National Lab for condensed {2. physics and institute of physics Chinese Academy of Sciences Beijing 100080 China Department of physics Oklahoma State University Stillwater Oklahoma 74078 USA

We study the magnetic field effects on the spin-polarized transport of the quantum dot (QD) spin valve inthe sequential tunneling regime. A set of generalized master equation is derived. Based on that, we discuss the collinearand noncollinear magnetic field effects, respectively. In the collinear magnetic field case, we find that the Zeeman splittingcan induce a negative differential conductance (NDC), which is quite different from the one found in previous *** has a critical polarization in the parallel arrangement and will disappear in the antiparallel configuration. In thenoncollinear magnetic field case, the current shows two plateaus and their angular dependence is analyzed. Althoughsometimes the two current plateaus have similar angular dependence, their mechanisms are different. Our formalism isalso suitable for calculating the transport in magnetic molecules, in which the spin splitting is induced not by a magneticGeld but by the intrinsic magnetization.

关键词： spin value spintronics quantum dot

High-pressure synthesis and properties of CeO_2.ZrO_2.solid solution

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chinese Science Bulletin 2001年第10期46卷 801-806页

作者： XU Dapeng, WANG Quanyong, LU Zhe, LIU Zhiguo, ZHANG Gongmu & SU Wenhui1. Department of physics, Jilin University, Changchun 13002. china 2. International {2. for Materials physics, chinese academy of sciences, Shenyang 110015, china 3. {2. for condensed matter and Radiation physics, china {2. of Advanced Science and Technology (World Laboratory),{12., china Department of physics Jilin University Changchun China International center for Materials physics Chinese Academy of Sciences Shenyang China center for condensed {2. and Radiation physics China Center of Advanced Science and Technology (World Laboratory) Beijing China

Using nanoparticles of CeO2.and ZrO2.prepared by the chemical precipitation method as starting materials, the single-phase cubic Ce0.5Zr0.5O2.solid solution (c-Ce0.5Z0.5O2. has been synthesized under 3.1 GPa at 1073 K for the first time. The structure of the c-Ce0.5Zr0.5O2.has not been changed before and after annealing at 773 K for 1 h. Only an unknown EPR signal (g =1.990) has been observed in the c-Ce0.5Zr0.5O2.and not varied after annealing at 773 K for 1 h, which exhibited that there exists no Ce3+ in the c-Ce0.5Zr0.5O2.and the Ce4+ has not been reduced into Ce3+ after annealing. The transport mechanism is ionic for the c-Ce0.5Zr0.5O2. The bulk conductivity (a =1.2.10-5 S/cm at 82. K, σ=2.1 ×10-3 S/cm at 112. K) is the same as that of CeO2. but smaller than that of Y2.3-stabilized ZrO2. A marked curvature at T = 82. K has been observed in the Arrhenius plot of the bulk conductivity. The activation energy below 82. K is lower than that above 82. K, and the reason has been discussed.

关键词： CeO2.ZrO2 nanocrystalline high-pressure and -temperature solid-state reaction solid solution.

Studies of Structure Evolution of Nanostructured Hf_(11)Ni_(89) Alloy

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Journal of Materials Science & Technology 1998年第3期14卷 205-210页

作者： Zhenfu DONG and Lianmao PENG(beijing Lab. of Electron Microscopy, institute of physics and {2. for condensed matter physics,chinese academy of sciences, P.O.Box 2.2., beijing 100080, china)Ke LU and Zhuangqi HU(State Key Lab. for RSA, institute of Meta beijing Lab. of Electron Microscopy Institute of Physics and Center for Condensed Matter Physics Chinese Academy of Sciences P.O.Box 2724 Beijing 100080 China State Key Lab. for RSA Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

A nanostructured Hf11Ni89 ribbon sample was prepared by melt-spinning. It was found that the as-quenched sample is composed of a major HfNi5 compound nanophase and an interfacial magnetic Ni(Hf) solid solution phase. The structure evolution of the sample was studied by using X-ray difFraction (XRD), transmission electron microscopy (TEM), difFerential scanning calorimetry (DSC), resistivity and magnetothermal analysis. Upon heating, a second precipitation process of the Ni(Hf) phase prior to grain growth wa5 detected by means of both structural analysis and physical property measurements. The measurement results are discussed based on the relationship between microstructure and physical properties.

关键词： Studies of Structure Evolution of Nanostructured Hf Alloy Ni

Negative refraction in two-dimensional photonic crystals

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Progress in Natural Science:Materials International 2006年第10期16卷 1027-1032页

作者： REN Xiaobin, REN Kun, FENG Zhifang, FENG Shuai and REN Cheng ( School of physics Science and Information Technology, Liaocheng University, Liaocheng 2.2.59, china {2. National Laboratory for condensed matter physics, institute of physics, chinese academy of sciences, beijing 100080, china) School of physics Science and Information Technology Liaocheng University Liaocheng 252059 China beijing National Laboratory for condensed {2. physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

Recent progress made in research on negative refraction in two-dimensional photonic crystals is reviewed. Special attentions are paid to the research results of our group. We explore the underlying mechanism governing the occurrence of negative refraction in periodic and quasiperiodic photonic crystals. These results may be useful references for the application of photonic crystals. The perspectives of future research on negative refraction are briefly predicted.

关键词： negative refraction photonic crystals superlens subwavelength imaging equifreqnency surface.

Colossal magnetoresistive p-n junctions of perovskite oxide La_(0.9)Sr_(0.1)MnO_3/SrNb_(0.01)Ti_(0.99)O_3

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chinese Science Bulletin 2003年第13期48卷 1328-1330页

作者： L Huibin, DAI Souyu, CHEN Zhenghao, YAN Lei, ZHOU Yueliang & YANG Guozhen Laboratory of Optical physics, institute of physics & {2. for condensed matter physics, chinese academy of sciences, 100080 beijing, china Laboratory of Optical physics Center for Condensed Matter Physics Chinese Academy of Sciences 100080 Beijing China

We have successfully fabricated the colossal magnetoresistive (CMR) p-n junctions of perovskite oxide La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 (LSMO/SNTO) with laser molecular beam epitaxy. The I-V characteristics of the LSMO/SNTO p-n junctions as a function of applied magnetic field (05 T) were studied between 100 and 300 K. We found that the p-n junction exhibited the CMR behavior. The CMR ratio rR/R0 (rR = RH - R0) is positive in magnetic fields below 0.13 T and at high temperature, while it displays a negative CMR near 100 K and in magnetic fields over 0.13 T. The CMR ratio values are 8% at 0.1 T and 13% at 5 T and 300 K, 40% at 0.1 T and 150 K, 10% at 0.13 T and 60% at 5 T and 100 K. The CMR behavior of the p-n junction is different from those of the LaMnO3 compound family.

关键词：巨磁电阻钙钛矿氧化物 LSMO/SNTO CMR 激光分子束外延超导体

New quantum tunneling steps in Mn_(11)Cr/Mn_(12. mixed crystal

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Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1769-1771页

作者： ZHOU YuRong1,LI YanRong1,FAN ZhenJun2.& WANG YunPing1 1beijing National Laboratory for condensed {2. physics,institute of physics,chinese academy of sciences,beijing 100190,china 2.chool of Materials sciences and Technology,china University of Geosciences,beijing 430074,china beijing National Laboratory for condensed {2. physics Institute of Physics Chinese Academy of Sciences Beijing China School of Materials sciences and Technology China University of Geosciences Beijing China

Magnetic properties of Mn11Cr and Mn12.mixed crystal at low temperature are studied.A new set of quantum tunneling steps discovered in magnetization curves suggests that there may exist another kind of single molecula... 详细信息

关键词： quantum tunneling molecular magnet magnetization curve