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MB_8^(2.) (M=Be,Mg,Ca,Sr,and Ba):Planar octacoordinate alkaline earth metal atoms enclosed by boron rings

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Science china Chemistry 2010年第8期53卷 1737-1745,1829-1832页

作者： PU ZhiFeng1,GE MaoFa1 & LI QianShu2.1State key laboratory for Structural Chemistry of Unstable and Stable Species {2. National laboratory for Molecular Sciences (BNLMS) institute of Chemistry,chinese academy of Sciences,{2. 100190,china 2.enter for Computational Quantum Chemistry,South china Normal University,Guangzhou 510631,china State key laboratory for Structural Chemistry of Unstable and Stable Species beijing National laboratory for Molecular Sciences (BNLMS) institute of Chemistry Chinese Academy of Sciences Beijing China Center for Computational Quantum Chemistry South China Normal University Guangzhou China

Complexes involving planar octacoordinate alkaline earth metal atoms in the centers of eight-membered boron rings have been investigated by two density functional theory (DFT) ***82.with D8h symmetry is predicted to be stable,both geometrically and electronically,since a good match is achieved between the size of the central beryllium atom and the eight-membered boron *** contrast,the other alkaline earth metal atoms cannot be stabilized in the center of a planar eight-membered boron ring because of their large *** following the out-of-plane imaginary vibrational frequency,pyramidal C8v MgB82.,CaB82.,SrB82.,and BaB82.structures are *** presence of delocalized π and σ valence molecular orbitals in D8h BeB82.gives rise to aromaticity,which is reflected by the value of the nucleus-independent chemical *** D8h BeB82.structure is confirmed to be the global minimum on the potential energy surface.

关键词： density functional theory octacoordinate alkaline earth metal aromatic molecular orbital

Synthesis,characterization,and thermostability of bis(2.2.6,6-tetramethyl-3,5-heptanedionato)copper(Ⅱ)

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Rare Metals 2012年第4期31卷 343-349页

作者： ZHANG Teng,GU Hongwei,DING Fazhu,QU Fei,and DAI Shaotao key laboratory of Applied Superconductivity,{2. of Electrical Engineering,chinese academy of Sciences,beijing 100190,china key laboratory of Applied Superconductivity Institute of Electrical Engineering Chinese Academy of Sciences Beijing China

Owing to the adaptability to large scale processing,excellent composition control and film uniformity,the metal-organic chemical vapor deposition（MOCVD） technique is a promising process for high-temperature superconductor YBa;Cu;O;（YBCO） *** this technique,the evaporation characteristics and thermostability of adopted precursors in whole process will decide the quality and reproducible results of YBCO *** the present report,bis（2.2.6,6-tetramethyl-3,5-heptanedionato）copper（II）(Cu（TMHD）;) was synthesized by the interaction of copper acetate hydrate with TMHD in methanol solution,and its structure was identified by FTIR,1 H NMR,and EI-MS ***,thermal property and the kinetics of decomposition were systematically investigated by nonisothermal thermogravimetric analysis methods（TGA） at different heating rates in streams of N;,and the average apparent activation energy of evaporation process was evaluated by the Ozawa,Kissinger,and Friedman *** possible conversion function was estimated through the Coats-Redfern method to characterize the evaporation patterns and followed a phase boundary reaction mechanism by the contracting area equation with average activation energy of 85.1 kJ·mol;.

关键词： Cu(TMHD)_2 metal-organic chemical vapor deposition(MOCVD) synthesis thermostability

VISCOELASTIC BEHAVIOR OF THE NON-HOOKE DEFORMATION BEFORE YIELDING IN UNIAXIAL DRAWING OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)

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chinese Journal of Polymer Science 2001年第4期19卷 399-405页

作者： Zhen-hua Yuan De-yan Shen Ren-yuan Qian Polymer physics laboratory Center for Molecular Science, {2. of Chemistry chinese academy of Sciences, beijing 100080 china 中科院化学所高分子物理及化学国家重点实验室北京

Viscoelastic behavior of the non-Hooke deformation of amorphous PET film before yield was investigated in the temperature region 74-80.5 degreesC around the glass transition temperature. The film specimen was drawn to yield point followed by unloading to zero stress, then the residual deformation was held constant; while the subsequent evolution of the stress was recorded. An induction period was found in the course of stress evolution followed by a stress step-increase. The induction period decreases with increasing drawing temperature with an activation energy of 1.10 MJ/mol.K, which is attributed to the time needed for the relaxation of rubbery deformation through cooperative internal rotations. At temperatures lower than 74 degreesC, there is no stress increase or the induction period becomes too long to be observed. Thus the nature of anelasticity in the non-Hooke region before yielding is attributed to stress induced rubbery deformation. The experimental results are interpreted in terms of Perez' theological model of a series connected Hooks spring and a Voigt element consisting of a parallel connected elastic spring and a dashpot.

关键词： pre-yield deformation PET uniaxial drawing non-Hooke deformation viscoelasticity stress induced rubbery deformation

Quantifying the effectiveness of SiO_2.Au light trapping nanoshells for thin film poly-Si solar cells

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Science china(Technological Sciences) 2010年第8期53卷 2228-2231页

作者： BAI YiMing 1 ,WANG Jun 2.,CHEN NuoFu 1,3 ,YAO JianXi 1 ,YIN ZhiGang 3 ,ZHANG Han 3 , ZHANG XingWang 3 ,HUANG TianMao 3 ,WANG YanShuo 3 &YANG XiaoLi 3 1School of Renewable energy Engineering,North china Electric Power University,{2. 102.06,china 2.National Engineering Research Center for Optoelectronic Devices,institute of Semiconductors, chinese academy of Sciences,PO Box 912.{2. 100083,china 3 key laboratory of Semiconductor Materials Science,institute of Semiconductors, chinese academy of Sciences,PO Box 912.{2. 100083,china School of Renewable energy Engineering North China Electric Power University Beijing China National Engineering Research Center for Optoelectronic Devices Institute of Semiconductors Chinese Academy of Sciences Beijing China key laboratory of Semiconductor Materials Science Institute of Semiconductors Chinese Academy of Sciences Beijing China

In order to enhance light absorption of thin film poly-crystalline silicon(TF poly-Si)solar cells over a broad spectral range, and quantify the effectiveness of nanoshell light trapping structure over the full solar spectrum in theory,the effective photon trapping flux(EPTF)and effective photon trapping efficiency(EPTE)were firstly proposed by considering both the external quantum efficiency of TF poly-Si solar cell and scattering properties of light trapping *** EPTF,EPTE and scattering spectrum exhibit different behaviors depending on the geometric size and density of nanoshells that form the light trapping *** an optimum size and density of SiO2.Au nanoshell light trapping layer,the EPTE could reach up to 40%due to the enhancement of light trapping over a broad spectral range,especially from 500 to 800 nm.

关键词： thin film poly-crystalline silicon surface plasmons SiO2.Au nanoshell

Laser Remelting of Plasma Sprayed NiCrAlY and NiCrAlY-Al_2._3 Coatings

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Journal of Materials Science & Technology 2001年第5期17卷 525-528页

作者： Yingna WU, Gang ZHA NC, Bingchun ZHANG, Zhongchao FENG and Yong LIANG institute of Metal Research, chinese {2. of Sciences, Shenyang 110016, china Fangjun LIU key laboratory for high energy Density Beam Processing Technology, beijing Aeronautical Manu Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12.3) were remelted by a 5 kW cw CO2.laser. With increasing laser power and decreasing traverse speed in the ranges of 2.0-700 W and 5-30 mm/s respectively, the melted track grew in width and depth. In the optimum range of laser parameters, a homogeneous remelted layer without voids, cavities, unmelted particles and microcracks was formed. On the surface of remelted layers, Al2.3 and YAIO3 were detected. As a result of isothermal oxidation tests, weight gains of laser remelted coatings were obviously lower than that only plasma sprayed, especially laser remelted NiCrAlY-Al2.3 coatings. The effects of laser remelting and incorporation of A12.3 second phase in N1CrAlY matrix on high temperature oxidation resistance were discussed.

关键词： Ni Laser Remelting of Plasma Sprayed NiCrAlY and NiCrAlY-Al2.3 Coatings TBCS Al

EI NIO PHENOMENON AND EXTENDED ASSOCIATE PATTERN ANALYSIS

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Journal of Hydrodynamics 2004年第1期16卷 90-100页

作者： CUIMao-chang MOJun QIAOFang-li instituteofOceanology ChineseAcademyofSciences.Qingdao266071China／KeyLaboratoryofMarineScienceandNumericalmodelingTheFirstInstituteofOceanographyStateOceanicAdministrationQingdao266061China. instituteofOceanology ChineseAcademyofSciences.Qingdao266071China keylaboratoryofMarineScienceandNumericalmodeling TheFirstInstituteofOceanographyStateOceanicAdministrationQingdao266061China

To study the causes of El Nino Phenomenon the Extended Associate PatternAnalysis (EAPA) is set up with monthly sea surface wind stress and precipitation besides Sea LevelPressure (SLP) and Sea Surface Temperature (SST) in or over the Pacific and related seas since 1979in present paper. The results show that El Nino Phenomenon means a SST redistribution, coveringalmost the whole Pacific that needs a huge amount of energy provided by air-sea interaction in themost Pacific regions; It is the wester burst and wind convergence, coming from meddle latitudesdirectly, instead of Kelvin waves that produce the strong SST warm signal in Nino regions; Twonegative SLP anomalies in middle of the North and South Pacific, most likely produced by the averageair pressure decreasing effect of explosive cyclones through precipitation, and the positive SLPanomaly o-ver the Asia-Australia land bridge, coming mainly from the south hemisphere with a littleinfluence from the Asian continent, are the three major causes for El Nino onset, they work togetherto produce anomalous wind convergence in Nino regions and wester burst in middle of the North andSouth Pacific that result in a warm tongue and cold pincers gearing together; Basically, during itsearly stage the ocean is forced by the atmosphere, while during its late stage the atmosphere isforced by the ocean.

关键词： extended associate pattern analysis (EAPA) El nino phenomenon

A Self-consistent Calculation and an Anisotropic Wavelength Cut off energy of Spin-wave Spectrumin Magnetic Tunnel Junctions

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Journal of Materials Science & Technology 2001年第2期17卷 197-202页

作者： Xiufeng HAN State key laboratory of Magnetism, {2. of physics, chinese academy of Sciences, beijing 100080, china Terunobu Miyazaki Department of Applied physics, Graduate School of Engineering, Tohoku University, Aoba-yama 08, Sendai 980-8579, Japa State key Lab. of Magnetism Inst. of Phys. Chinese Acad. of Sci. Beijing 100080 China

Temperature dependence of tunnel magnetoresistance (TMR) ratio, resistance, and coercivity from 4.2.K to room temperature (RT), applied de bias voltage dependence of the TMR ratio and resistances at 4.2.K and RT, tunnel current I and dynamic conductance dI/dV as functions of the de bias voltage at 4.2.K, and inelastic electron tunneling (IET) spectroscopy, d(2.I/dV(2. versus V, at 4.2.K for a tunnel junction of Ta(5 nm)/Ni79Fe2.(2. nm)/Ir2.Mn78(12.nm)/Co75Fe2.(4 nm)/Al(0.8 nm)-oxide/Co75Fe2.(4 nm)/Ni79Fe2.(2. nm)/Ta(5 nm) were systematically investigated. high TMR ratio of 59.2. at 4.2.K and 41.3% at RT were observed for this junction after annealing at 2.5 degreesC for an hour. The temperature dependence of TMR ratio and resistances from 4.2.to 300 K at 1.0 mV bias and the de bias voltage dependence of TMR ratio at 4.2.K from 0 to 80 mV can be evaluated by a comparison of self-consistent calculations with the experimental data based on the magnon-assisted inelastic excitation model and theory. An anisotropic wavelength cutoff energy of spin-wave spectrum in magnetic tunnel junctions (MTJs) was suggested, which is necessary for self-consistent calculations, based on a series of IET spectra observed in the MTJs.

关键词： off TMR A Self-consistent Calculation and an Anisotropic Wavelength Cut energy of Spin-wave Spectrumin Magnetic Tunnel Junctions wave Figure than

Numerical exploration of new features on three-dimensional transition of a cylinder wake

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Science china Mathematics 2004年第Z1期47卷 69-80页

作者： LING Guocan, XIONG Jun & ZHU KeqinState key laboratory of Nonlinear Mechanics, {2. of Mechanics, chinese academy of Sciences, beijing 100080, china Department of Engineering Mechanics, Tsinghua University, beijing 100084, china State key laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing China Department of Engineering Mechanics Tsinghua University Beijing China

The three-dimensional transition of the wake flow behind a circular cylinder is studied in detail by direct numerical simulations using 3D incompressible N-S equations for Reynolds number ranging from 2.0 to 300. New features and vortex dynamics of the 3D transition of the wake are found and investigated. At Re = 2.0, the flow pattern is characterized by mode A instability. However, the spanwise characteristic length of the cylinder determines the transition features. Particularly for the specific spanwise characteristic length linear stable mode may dominate the wake in place of mode A and determine the spanwise phase difference of the primary vortices shedding. At Re = 2.0 and 300 it is found that the streamwise vortices evolve into a new type of mode "dual vortex pair mode" downstream. The streamwise vortex structures switch among mode A, mode B and dual vortex pair mode from near wake to downstream wake. At Re = 2.0, an independent low frequency fm in addition to the vortex shedding frequency fs is identified. Frequency coupling between fm and fs occurs. These result in the irregularity of the temporal signals and become a key feature in the transition of the wake. Based on the formation analysis of the streamwise vorticity in the vicinity of cylinder, it is suggested that mode A is caused by the emergence of the spanwise velocity due to three dimensionality of the incoming flow past the cylinder. energy distribution on various wave numbers and the frequency variation in the wake are also described.

关键词： cylinder, wake, 3D transition, Fourier-spectral-spectral-element method, direct numerical simulation (DNS).

Adsorption of zinc on manganite(γ-MnOOH): particle concentration effect and adsorption reversibility

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Journal of Environmental Sciences 2004年第4期16卷 627-630页

作者： QIN Yan-wen1, PAN Gang 1,2., ZHANG Ming-ming1, LI Xian-liang1 (1. State key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, {2. academy of Sciences, beijing 100085, china. 2. Qingdao University of Science & Technology, Qingdao 2.6042. china) State key laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China.

The adsorption and desorption processes of Zn(Ⅱ) on γ-MnOOH as a function of particle concentrations(C p) were studied. An obvious C p effect was observed in this adsorption system. The degree of adsorption hysteresis increased greatly with the increasing of C p, indicating that the extent of the real metastable-equilibrium states deviating from the ideal equilibrium state was enhanced with the increasing of C p. The C p-reversibility relationship confirmed the metastable-equilibrium adsorption(MEA) inequality(Pan, 1998a), which was the core formulation of the MEA theory. Because the MEA inequality was based on the basic hypothesis of MEA theory that adsorption density Γ is not a state variable, the C p-reversibility relationship gave indirect evidence to the basic hypothesis of MEA theory.

关键词： zinc γ-MnOOH adsorption reversibility