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Investigation of a New Exsolved Cu-Fe-S Phase in“Abnormal Sphalerite”

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Acta Geologica Sinica(English Edition) 1991年第1期65卷 27-36,110-111页

作者： Li Jiuling Wang Su institute of Mineral Deposits, chinese {2. of Geolgical sciences,beijing beijing laboratory of electron microscopy, chinese academy of sciences, beijing institute of Mineral Deposits Chinese Academy of Geolgical Sciences Beijing China

A new exsolved copper-iron-sulfur phase in sphalerite has been found in the Dajing cassiterite- sulfidecopper-silver-tin deposit, Inner Mongolia, china. After investigating the optical properties, chemical composi-tion, crystal structure and exsolved Characters of the exsolved phase, the authors present important evidencefor its being a new exsolved copper-iron-sulfur phase mineral. Its formation mechenism is discussed in consider-ing heating experiments, phase equilibrium data and the geology of the deposit.

关键词： Ph Fe Abnormal Sphalerite Cu

An Explicit Function Expression for dc Bias and Temperature Dependence of Magnetoresistances in Magnetic Tunnel Junctions

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Journal of Materials Science & Technology 2002年第6期18卷 497-501页

作者： Xiufeng HANState Key laboratory of Magnetism, institute of physics and Center of Condensed Matter {2., chinese academy of sciences, beijing 100080, china chinese Acad Sci Inst Phys State Key Lab Magnetism Beijing 100080 Peoples R China chinese Acad Sci Ctr Condensed Matter Phys Beijing 100080 Peoples R China

An explicit function expression for the bias voltage or/and temperature dependences of tunnel magnetoresistance ratio and resistances were obtained with a unique set of intrinsic parameters. Two of these intrinsic parameters are the Curie temperature TC and the density of state (DOS) for itinerant majority and minority electrons ξ(ρM/ρm), which are the eigen parameters of ferromagnetic electrodes. Others are the spin-dependent matrix-element ratio (i.e., |Td|2.|TJ|2.) and the anisotropic-wavelength-cutoff energy ECγ of spin-wave spectrum in magnetic tunnel junction (MTJ), which are the structure parameters of an MTJ. These intrinsic parameters can be predetermined using the experimental measurement or, in principle, using the first-principle calculation method for an MTJ with the three key layers of FM/I/FM. Furthermore, a series of experimental data for an MTJ, for example, a spin-valve-type MTJ of Ta (5 nm)/Ni79Fe2.(2. nm)/lr2.Mn78(12.nm)/Co75Fe2.(4 nm)/AI(0.8 nm)-oxide/Co75Fe2.(4 nm)/Ni79Fe2.(2. nm)/Ta (5 nm) in this work, can be self-consistently evaluated and explained using such concise explicit function formulations.

关键词： Magnetic tunnel junction TMR Spin-electron transport Magnon excitation Spin-polarization Magnetotransport

Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

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Science china(physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2, CHEN ZhengHao3 & ZHANG XiaoZhong4,5 1 Key laboratory of Beam Technology & Materials Modification of the Ministry of Education, institute of Low Energy Nuclear physics, beijing Normal University, beijing 100875, china 2 beijing Radiation Center, beijing 100875, china 3 laboratory of Optical physics, institute of physics, chinese academy of sciences, beijing 100080, china 4 Key laboratory of Advanced Materials of the Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, beijing 100084, china 5 beijing National Center for electron microscopy, Tsinghua University, beijing 100084, china 1. Key laboratory of Beam Technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing Radiation Center Beijing 100875 China 3. laboratory of Optical physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 4. Key laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing 100084 China 5. beijing National Center for electron {2. Tsinghua University Beijing 100084 China

The LaMn1-xTexO3+δ (x=0.1, 0.2. 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XPS) shows that in the samples the Te ions have a valence of Te4+, and Mn3+ ions are partly converted into Mn2. and Mn4+ due to the excess oxygen and Te doping. The magnetotransport associated with Mn2., Mn3+ and Mn4+ was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2. and Mn4+; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2. and Mn4+. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport

Study on the atmospheric photochemical reaction of CF_3 radicals using ultraviolet photoelectron and photoionization mass spectrometer

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Science china Chemistry 2008年第4期51卷 316-321页

作者： YAO Li1,2. DU Lin1,2. YIN Shi1,2.& GE MaoFa1 1 beijing National laboratory for Molecular {2. (BNLMS), State Key laboratory for Structural Chemistry of Unstable and Stable Species, institute of Chemistry, chinese academy of sciences, beijing 100080, china 2.Graduate University of chinese academy of sciences, beijing 100080, china 1. beijing National laboratory for Molecular {2. (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 2. Graduate University of chinese academy of sciences Beijing 100080 China

A study of the atmospheric photochemical reaction of CF3 radical with CO and O2.was performed by using a homemade ultraviolet photoelectron spectrometer-photoionization mass spectrometer (PES- PIMS). The electronic structures and mechanism of ionization and dissociation of CF3OC(O)OOC(O)- OCF3 were investigated. It was indicated that the two bands on the photoelectron spectrum of CF3OC(O)OOC(O)OCF3 are the result of ionization of an electron from a lone pair of oxygen and a fluo- rine lone pair of CF3 group. The outermost electrons reside in the oxygen lone pair. The experimental and theoretical first vertical ionization energy is 13.2. and 13.178 eV, respectively, with the PES and OVGF method. They are in good agreement. The photo ionization and dissociation processes were discussed with the help of theoretical calculations and PES-PIMS experiment. After ionization, the parent ions prefer the dissociation of the C-O bond and giving the fragments CF3OCO+ and CF3+. It demonstrated that the ultraviolet photoelectron and photoionization mass spectrometer could be ap- plied widely in the study of atmospheric photochemical reaction.

关键词： photochemical reaction CF3 radical ultraviolet photoelectron and photoionization mass spectroscopy transient species

Experimental study of electron capture excitation in collisions between Li-like N^(4+) ions and Na atoms

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chinese Science Bulletin 1997年第5期42卷 368-371页

作者： LIU Zhanwen, ZHOU Sixin, ZHANG Wen, ZHANG Xuezhen GUOXiaohong, WANG Youde, MA Xinwen, YANGZhihu, LIU Huiping, ZHAO Mengchun, YANG Feng, PAN Guangyan and LI Dawan1. institute of Modern physics,{2., Lanzhou 730000, china 2. institute of physics,{2., beijing 100080, china institute of Modern physics Chinese Academy of Sciences Lamhou China institute of Physia Chinese Academy of Sciences Beijing China

WITH the rapid development of the technique of ionized atoms, the charge states of atoms that can be obtained now are so high that the H-like U91+ ions and naked U92. ions

关键词： single electron capture double electron capture emission cross section excited states.

Structures and physical properties of rigid polyurethane foams with water as the sole blowing agent

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Science china Chemistry 2006年第4期49卷 363-370页

作者： LI Xiaobin1,2. CAO Hongbin1 & ZHANG Yi1 1. institute of Process Engineering, chinese academy of sciences,{2., china 2. Graduate School of the chinese academy of sciences, beijing 100039, china 1. institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China 2. Graduate School of the chinese academy of sciences Beijing 100039 China

Rigid polyurethane foams blown by varying water level were prepared in this study. The structures and physical properties of rigid polyurethane foams blown by water were measured with FT-IR, universal testing machine (Instron3365), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that polyurea and polybiuret were the typical charac- teristics, and the cream time and gel time were shorter for the fully water blown rigid foams than that for the fully cyclopentane blown foams. The density of foam samples decreased from 45.0 kg/m3 to 2..4 kg/m3 with the increase of water level from 3 pph to 7 pph. Compressive strength exhibited the similar behavior with density. The average cell size of foam samples ranged from 2.1 μm to 356 μm with the increase of water level from 3 pph to 7 pph, respectively. At the same time, poorer dimen- sional stability was encountered with the increase of average cell size due to fast diffusion rate of CO2.out of the foam. The results of thermal analysis show that the glass transition temperature (Tg) shifted to a higher temperature with the increase of isocyanate level when more water was used as chemical blowing agent.

关键词： polyether polyol, polyurethane rigid foam, compressive strength, dimensional stability, cell size, glass transition temperature.

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 {2., institute of physics and Center 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 {2. 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

PHASE EXTENSION AND STRUCTURE ANALYSIS BY THE MAXIMUM ENTROPY METHOD

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Acta Metallurgica Sinica(English Letters) 1998年第4期11卷 241-254页

作者： G.B.Hu and Q.B.Yang (Department of physics, Xiangtan University, Xiangtan 411105, china)({2. laboratory of electron microscopy, Center for Condensed Matter physics, The chinese academy of sciences, P. O. Box 2.2., beijing 100080, china) Xiangtan Univ Xiangtan China

Excellent results are obtained in structure analysis with jew phases of structure factors by the maximum-entropy method (MEM) for CaGaN PbCO3 and ReBe2. single crystals. The computation time and memory space are minim... 详细信息

关键词： maximum entropy method structure analysis phase extension,symmetry

Studies on BEPC upgrade from pretzel to double-ring

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Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 2084-2089页

作者： ZHANG Chuang institute of High Energy physics,{2. academy of sciences,beijing 100049,china 1. institute of High Energy physics Chinese Academy of Sciences Beijing 100049 China

physics opportunity in the charm and τ energy region calls for higher luminosity of the beijing {2.-Positron Collider (BEPC).The BEPC has experienced continuous improvement since its completion in ***,as a major upgrading project of the BEPC,aims at enhancing its luminosity of factor 30–100,following the principle of "one machine,two purposes" as adopted in BEPC,so that both high energy physics and synchrotron radiation experiments can be carried out with *** the BEPC to BEPCII,the double-ring scheme with multi-bunch e +-e-collision in the large crossing angle was studied in comparison with the single-ring pretzel *** the dedicated synchrotron radiation operation,artful "bridges" are designed to connect two halves of the outer ring in both the southern and the northern crossing *** paper reviews the studies on the BEPC upgrade from pretzel to double-ring structure of BEPCII.

关键词： collider storage ring high energy physics synchrotron radiation