检索结果-南通市图书馆

同方期刊数据库

Superconductivity at 36 K in gadolinium-arsenide oxides GdO_(1-x)F_xFeAs

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2008年第6期51卷 719-722页

作者： CHENG Peng, FANG Lei, YANG Huan, ZHU XiYu, MU Gang, LUO HuiQian, WANG ZhaoSheng & WEN HaiHu National laboratory for Superconductivity, institute of physics, chinese academy of sciences, beijing 100190, china beijing National laboratory for Condensed Matter physics, institute of physics, chinese academy of sciences, beijing 100190, china 1. National laboratory for Superconductivity Institute of Physics Chinese Academy of Sciences Beijing 100190 China 2. beijing National laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China

In this paper we report the fabrication and superconducting properties of GdO1-xFxFeAs. It was found that when x is equal to 0.17, GdO0.83F0.17FeAs is a su-perconductor with the onset transition temperature Tcon ≈ 36.6 K. Resistivity anomaly near 130 K was observed for all samples up to x = 0.17, and such a phenomenon is similar to that of LaO1-xFxFeAs. Hall coefficient indicates that GdO1-xFxFeAs is conducted by electron-like charge carriers.

关键词： iron-based superconductor high-temperature superconductor

POLYMETHYLMETHACRYLATE FILMS IN THE STATE OF HIGH GLOBAL CHAIN ORIENTATION BUT NEARLY RANDOM SEGMENTAL ORIENTATION

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 1999年第3期17卷 215-220页

作者： Rui Song Jing Chen Jin-gui Gao Xin Lin Qing-rong Fan Polymer physics laboratory, institute of Chemistry, chinese academy of sciences, beijing 100080, china chinese Acad Sci Inst Chem Polymer Phys Lab Beijing 100080 Peoples R China

PMMA films in the high global chain orientation and nearly random segmental orientation (GOLR) state were prepared by uni-axially drawing at temperatures 20 similar to 30 degrees C above its glass transition temperature, T-g, and their isotropic and anisotropic properties were studied. Experimental results show that this kind of amorphous state, the GOLR state, is nearly isotropic in optical birefringence, IR-dichroism and X-ray diffraction patterns, but is very anisotropic in behaviors of thermal expansion, solvent-swelling and stress-strain.

关键词： orientation uniaxial stretching polymethylmethacrylate optical birefringence WAXD infrared spectroscopy

The size effect on transport properties of colossal magnetoresistance materials La_(0.67)Ca_(0.33)MnO_3

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 251-257页

作者： LI PeiGang1,2,LEI Ming1,2,GUO YanFeng2,GUO Xi2,CHEN LeiMing2, TANG WeiHua1,2,SONG PengYun3 & CHEN JinPing3 1 Department of physics,Center for Optoelectronics Materials and Devices,Zhejiang Sci-Tech University,Hangzhou 310018,china 2 National laboratory for Condensed Matter physics,institute of physics,chinese academy of sciences,beijing 100080,china 3 Department of physics,Peking University,beijing 100875,china 1. Department of physics Center for Optoelectronics Materials and Devices Zhejiang Sci-Tech University Hangzhou 310018 China 2. National laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 3. Department of physics Peking University Beijing 100875 China

High quality La0.67Ca0.33MnO3 (LCMO) film was deposited via a novel pulsed electron deposition technique on SrTiO3(100) single crystal substrate. The micro-bridge with different widths was fabricated by using electron beam lithography (EBL) technique and their transport properties were studied. For the micro-bridges with width of 2 and 1.5 μm,the insulator-to-metal transition temperature (TP) keeps un-changed compared with the film. For the micro-bridges with width of 1 μm,the TP shifts towards the lower temperature by 50 K. When the width decreases down to 500 nm,the insulator-to-metal transition disappears. The magnetoresistance be-havior of these micro-bridges was studied,and the results show that the low field magnetoresistance (LFMR) decreases and the high field magnetoresistances (HFMR) keep almost unchanged as the width of micro-bridge is reduced.

关键词： colossal magnetoresistance pulsed electron deposition electron beam lithography electrical transport properties

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2004年第5期47卷 612-620页

作者： ZENG Zhaoquan1,3, WANG Yong2, DU Xiaolong1, MEI Zengxia1, KONG Xianghe3, JIA Jinfeng1, XUE Qikun1 & ZHANG Ze2, 4 1. State Key laboratory for Surface physics, institute of physics, chinese academy of sciences, beijing 100080, china 2. laboratory of Electron Microscopy, institute of physics, chinese academy of sciences, beijing 100080, china 3. College of physics and Engineering, Qufu Normal University, Qufu 273165, china 4. beijing University of Technology, beijing 100022, china 1. State Key laboratory for Surface physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 2. College of physics and Engineering Qufu Normal University 273165 Qufu China 3. laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences 100080 Beijing China 4. beijing University of Technology 100022 Beijing China

A Ga wetting layer was used to modify the surface structure of sapphire (0001) substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30 rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high energy electron diffraction, ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth.

关键词： Ga wetting layer, sapphire, polarity, defect density, zinc oxide, rf-MBE, RHEED, HRXRD, TEM, CBED.

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

在线全文

学校读者我要写书评

暂无评论

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 Matter physics, institute of physics,chinese academy of sciences,beijing,100190,china beijing National laboratory for Condensed Matter 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 FeSO4·7H2O 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

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 Matter, institute of physics, chinese academy of sciences, beijing 100080, china 1. beijing National laboratory of Condensed Matter Institute of Physics Chinese Academy of Sciences Beijing 100080 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 20 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 20% value after 144 h within 300 h.

关键词： GaN InGaN white light LED MOCVD

Synthesis and Crystal Structure of [Cis-1,10phenanthroline-palladium(Ⅱ)(THF)_2]dinitrate (THF = Tetrahydrofuran)

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Structural Chemistry 2003年第5期22卷 547-549页

作者： HUANG Hui YU Shu-Yan② (State Key laboratory of Polymer physics and Chemistry, Joint laboratory of Polymer Science and Materials, institute of Chemistry, The chinese academy of sciences, beijing 100080, china) institute of Chemistry The Chinese Academy of Sciences State Key Laborator6y of Polymer Physics and Chemistry Joint Laboratory of Polymer Science and Materials CAS 北京 100080

A mononuclear complex, cis-1,10-phenanthroline-palladium(Ⅱ)(THF)2]dinitrate (THF = tetrahydrofuran) [Pd(C10H8N2)(C4H8O)2](NO3)2 1, has been prepared and structurally characterized by single-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group P21/c with a = 7.881(1), b = 27.371(3), c = 10.178(1) ? ?= 103.313(3)? V = 2136.5(4) 3, Mr = 554.83, Dc = 1.725 g/cm3, Z = 4, F(000) = 1128 and (MoK) = 0.926 mm-1. The structure was refined to R = 0.0678 and wR = 0.1651 for 1687 observed reflections with I > 2(I). It is revealed that the central Pd(Ⅱ) ion in the title complex is bonded to two THF and two phenanthroline molecules in a cis-configuration to form the coordination geometry, deviating slightly from the square plane.

关键词： crystal structure Pd(Ⅱ) complex 1,10-phenanthroline

Negative refraction in two-dimensional photonic crystals

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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 252059, china beijing National laboratory for Condensed Matter physics, institute of physics, chinese academy of sciences, beijing 100080, china) [a]School of physics Science and Information Techonolgy Liaocheng University Liaocheng China [b]beijing National laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 & Center 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