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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 {2., beijing Normal University, beijing 100875, China 2.beijing Radiation Center, beijing 100875, China 3 laboratory of Optical {2., institute of physics, chinese academy of sciences, beijing 1.0080, 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 Key laboratory of Beam Technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China beijing Radiation Center Beijing China laboratory of Optical physics Institute of Physics Chinese Academy of Sciences Beijing China Key laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing China beijing national Center for Electron Microscopy Tsinghua University Beijing 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 {2. for Molecular sciences (BNLMS), State Key {2. for Structural Chemistry of Unstable and Stable Species, institute of Chemistry, chinese academy of sciences, beijing 1.0080, China 2.Graduate University of chinese academy of sciences, beijing 1.0080, China beijing national {2. for Molecular sciences (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing 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

Detection of protein microarrays by oblique-incidence reflectivity difference technique

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Science China(physics,Mechanics & Astronomy) 2010年第2期53卷 306-309页

作者： WEN Juan1,LU Heng1,WANG Xu1,YUAN Kun1,L HuiBin1,ZHOU YueLiang1,JIN KuiJuan1,YANG GuoZhen1,LI Wei2.& RUAN KangCheng2.1 beijing national {2. for condensed matter physics,institute of physics,chinese academy of sciences,beijing 100190,China 2.Key {2. of Proteomics,institute of Biochemistry and Cell Biology,Shanghai institute for Biological sciences,chinese academy of sciences,Shanghai 2.0031,China beijing national {2. for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing China Key laboratory of Proteomics Institute of Biochemistry and Cell Biology Shanghai Institute for Biological Sciences Chinese Academy of Sciences Shanghai China

Biological microarrays with different proteins and different protein concentrations are detected without external labeling by an oblique-incidence reflectivity difference (OIRD) technique. The initial experiment results reveal that the intensities of OIRD signals can distinguish the different proteins and concentrations of protein. The OIRD technique promises feasible applications to life sciences for label-free and high-throughput detection.

关键词： oblique-incidence reflectivity difference protein microarray label-free detection

Gasdynamic characteristics of toroidal shock and detonation wave converging

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Science China(physics,Mechanics & Astronomy) 2005年第6期48卷 739-749页

作者： TENG Honghui1,2.& JIANG Zonglin2.1. Key laboratory of High Temperature Gas Dynamics, institute of Mechanics, {2. academy of Sci- ences, beijing 1.0080, China 2. Graduate University of chinese academy of sciences, beijing 100039, China Key laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

The modified CCW relation is applied to analyzing the shock, detonation wave converging and the role of chemical reactions in the process. Results indicate that the shock wave is strengthened faster than the detonation wave in the converging at the same initial Mach number. Euler equations implemented with a detailed chemical reaction model are solved to simulate toroidal shock and detonation wave converging. Gasdynamic characteristics of the converging are investigated, including wave interaction patterns, observable discrepancies and physical phenomena behind them. By comparing wave diffractions, converging processes and pressure evolutions in the focusing area, the different effects of chemical reactions on diffracting and converging processes are discussed and the analytic conclusion is demonstrated through the observation of numerical simulations.

关键词： converging, CCW relation, shock wave, detonation wave.

Some evidence of drying trend over northern China from 1951 to 2.04

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chinese Science Bulletin 2006年第23期51卷 2913-2925页

作者： MA Zhuguo1,2.& FU Congbin1,2.1. Key laboratory of Regional Climate-Environment for Temperate East Asia, chinese academy of sciences, {2. 10002., China 2. START Regional Center for Temperate East Asia, institute of Atmos-pheric physics, chinese academy of sciences, {2. 10002., China Key laboratory of Regional Climate-Environment for Temperate East Asia Chinese Academy of Sciences Beijing China START Regional Center for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The surface wetness index, Palmer drought sererity index and the retrieval of soil moisture over China were calculated using monthly precipitation and monthly mean surface air temperature. Based on the contrast analysis of the variation of the above three indices and precipitation, the dry/wet spatio-temporal pattern of northern China in the last 54 years was revealed, and the evidence of drying trend over northern China was analyzed, especially. The results show the following four facts: (1) The drying trend is the main characteristic of the eastern part of Northwest China and the central part of North China since the 1980s and it was enhanced in the last 15 years mainly due to the precipitation decrease and the temperature increase; (2. During the last 54 years, there was only one dry/wet shift at the interdecadal scale occurring in the eastern part of Northwest China and the central part of North China in the late 1970s, which was related to 1977/1978 global abrupt change, whereas there were three shifts in Northeast China, one was in the mid 1990s and the other two were in 1965 and 1983, respectively; (3) Unlike the variation trend of other subregions of northern China, the western part of Northwest China is currently located in a relatively wetting period, which is weak-ened due to the temperature increase; (4) The extreme drought frequency is obviously increasing in the eastern part of Northwest China, the central part of North China and Northeast China since the 1980s, which is closely related to the precipitation decrease and temperature increase in these subregions.

关键词：中国北方干燥趋向干旱索引气候背景

Some key technics of drop tower experiment device of national Microgravity laboratory (China) (NMLC)

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Science China(Technological sciences) 2005年第3期48卷 305-316页

作者： ZHANG Xiaoqian 1 , YUAN Longgen 1 , WU Wendong 1 , TIAN Lanqiao 2.& YAO Kangzhuang 2.1. institute of Engineering Thermophysics,{2., beijing 1.0080, China 2. institute of Mechanics,{2., beijing 1.0080, China institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China institute of Mechanics Chinese Academy of Sciences Beijing China

Drop tower is an important ground based facility for microgravity science experiment. The technical performances of the drop tower NMLC are advanced compared with similar facilities in the US, Germany and Japan. The main components such as drop capsule, deceleration devices, release mechanism present its advantages and creativities.

关键词： drop tower facility,drop capsule,deceleration devices,release mechanism.

Effect of concentration on surfactant micelle shapes——A molecular dynamics study

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Science China Chemistry 2005年第5期48卷 470-475页

作者： GAO Jian1,2. GE Wei1 & LI Jinghai1 1. Multiphase Reaction laboratory, institute of Process Engineering,{2., beijing 1.0080, China 2. Graduate School of The{2., beijing 100085, China Multiphase Reaction laboratory Institute of Process Engineering Chinese Academy of Sciences Beijing China Graduate School of The chinese academy of sciences Beijing China

Many aspects of the behavior of surfactants have not been well understood due to the coupling of many different mechanisms. Computer simulation is, therefore, attractive in the sense that it can explore the effect of different mechanisms separately. In this paper, the shapes, structures and sizes of sodium dodecylbenzenesulfonate (SDBS) micelles under different con-centrations in an oil/water mixture were studied via molecular dynamics (MD) simulations using a simplified atomistic model which basically maintains the hydrophile and lipophile properties of the surfactant molecules. Above the critical micellar concentration (cmc), surfactant molecules ag-gregate spontaneously to form a wide variety of assemblies, from spherical to rodlike, wormlike and bilayer micelles. Changes in their ratios of the principle moments of inertia (g1/g3, g2.g3) in-dicated the transition of micelle shapes at different concentrations. The aggregation number of micelle is found to have a power-law dependence on surfactant concentration.

关键词： surfactant, MD simulation, sodium dodecylbenzenesulfonate, micelle shape.

Systematic distortion in cosmic microwave background maps

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Science China(physics,Mechanics & Astronomy) 2009年第5期52卷 804-808页

作者： LIU Hao 1,3 &LI TiPei 1,2.1Key laboratory of Particle Astrophysics,{2. of High Energy physics,chinese academy of sciences,beijing 100049,China 2.enter for Astrophysics,Tsinghua University,beijing 100084,China 3 Graduate University of chinese academy of sciences,beijing 100049,China Key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Center for Astrophysics Tsinghua University Beijing China

To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making *** inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these *** analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)*** detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

关键词： cosmology cosmic microwave background methods data analysis

Application of the moist vorticity vector in the analysis of a heavy rainfall event in North China

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Progress in Natural Science:Materials International 2007年第12期17卷 1457-1465页

作者： Zhao Yu1,2.3, Wang Jianguo4 and Xue Deqiang2.1. laboratory of Cloud-Precipitation physics and Severe Storms, {2. of Atmospheric physics, chinese academy of sciences, beijing 10002., China 2. Shandong Provincial Meteorological Observatory, Jinan 2.0031, China 3. Graduate University of chinese academy of sciences, beijing 100039, China 4. Shandong Provincial Meteorological Bureau, Jinan 2.0031, China) laboratory of Cloud-Precipitation physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Shandong Provincial Meteorological Observatory Jinan 250031 China Graduate University Chinese Academy of Sciences Beijing 100039 China Shandong Provincial Meteorological Bureau Jinan 250031 China

The moist vorticity vector (MVV), defined as (ζa×▽qv)/ρ introduced by Gao et al. is used to study a heavy rainfall event in North China. The MVV has zonal, meridional and vertical components in a three-dimensional framework. Analysis of domain-mean and mass-integrated quantities shows that the variation of the vertical component of the MVV closely follows the variation of the cloud hydrometeors, with a linear correlation coefficient of 0.95, indicating that the vertical component of the MVV is strongly associated with midlatitude convection. Further analysis shows that the vertical component of the MVV reflects the interaction between the horizontal vorticity and the horizontal specific humidity gradient, which can associate dynamic and thermodynamic processes with cloud microphysical processes. Thus, this study can help to understand how the interaction between circulations and clouds aids the development of convection, and the MVV can be used to trace the development and evolution of heavy rainfall.

关键词： moist vorticity vector heavy rainfall modeling study.