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Exchange bias for ferromagnetic/antiferromagnetic bilayers with the uniaxial anisotropy being misaligned with the exchange anisotropy

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Science china(Physics,Mechanics & Astronomy) 2009年第12期52卷 1885-1892页

作者： BAI YuHao1 & YUN GuoHong1,2 1 college of Physical Science and Technology,Inner Mongolia university,Hohhot 010021,china 2 Key Laboratory of Physics and chemistry of Functional Materials,college of Physics and Electronic Information,Inner Mongolia normal university,Hohhot 010022,china 1. college of Physical Science and Technology Inner Mongolia University Hohhot 010021 China 2. Key Laboratory of Physics and chemistry of Functional Materials College of Physics and Electronic Information Inner Mongolia Normal University Hohhot 010022 China

Using the principle of minimal energy and S-W model,the exchange bias for ferromagnetic/antiferro-magnetic bilayers has been investigated when the uniaxial anisotropy is misaligned with the exchange anisotropy. According to the relation between the energy of the bilayer and the orientation of ferro-magnetic magnetization,it is found that the bilayer will be in the monostable state or bistable state when the external field is absent in the initial magnetization state. The monostable state or bistable state of the bilayer,which determines the angular dependence of exchange bias directly,is controlled by the competition between the exchange anisotropy and uniaxial anisotropy. When the applied field is parallel to the intrinsic easy axes and intrinsic hard axes,one of the switching fields of the hysteresis loop shows an abrupt change,while the other keep continuous by analyzing the magnetization reversal processes. Consequently,the exchange bias field and the coercivity will show a jump phenomenon. The numerical calculations indicate that both the magnitude and direction of the exchange anisotropy will significantly affect the angular dependence of exchange bias. The jump phenomenon of exchange bias is an intrinsic property of the bilayer,which is dependent on the interfacial exchange-coupling constant,the orientation of the exchange anisotropy,the thickness and uniaxial anisotropy constant of the ferromagnetic layer.

关键词： monostable state bistable state intrinstic easy axis intrinstic hard axis switching field

Synthesis, Crystal Structures and Catalysis of Dinuclear Cd(Ⅱ) Complexes Bridged by Unusual (N,O,O′)-Coordinated α-Amino Acids

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Chemical Research in Chinese Universities 2012年第1期28卷 73-78页

作者： DENG Dong-sheng1,2, WANG Li1, PEI Ya-mei1, FENG Lu2 and LIU Chang-lin1 1. Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, School of chemistry, Central china normal university, Wuhan 430079, P. R. china 2. college of chemistry and Chemical Engineering, Luoyang normal university, Luoyang 471022, P. R. china School of chemistry Central China Normal University Key Laboratory of Pesticide & Chemical Biology Ministry of Education Wuhan 430079 college of chemistry and Chemical Engineering Luoyang Normal University Luoyang 471022

Four dinuclear amino acid cadmium（II） complexes [Cd2（tren）2（dl-alaninato）]（ClO4）3·H2O（I）, [Cd2（tren）2· （l-alaninato）]（ClO4）3·H2O（II）, [Cd2（tren）2（dl-phenylalaninato）]（ClO4）3（III） and [Cd2（tren）2（l-phenylalaninato）]· （ClO4）3（IV）, constructed from mixed ligands of tris（2-aminoethyl）amine（tren） and racemic or natural amino ac ids（amino acids=dl or l-alanine, and dl or l-phenylalanine）, have been synthesized and characterized by X-ray crys tallography. The structural analysis of complexes I and III reveals that the cadmium centers are coordinated by one tren ligand and one amino acid molecule with the unusual （N,O,O′）-bridged mode, resulting in asymmetric chromo phores of CdN4O and CdN5O in complex I, CdN4O2 and CdN5O in complex III, respectively. The utility of the four complexes as efficient water-compatible Lewis acid catalysts for the direct aldol reaction in water was examined. The reaction proceeded smoothly to afford the corresponding β-hydroxy ketones in up to 99% yield. Moreover, the dias tereoselectivity of the reaction favors the formation of the syn-isomers.

关键词： Dinuclear cadmium(II) complex Amino acid Aldol reaction

Scenario simulation and forecast of land use/cover in northern china

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Chinese Science Bulletin 2008年第9期53卷 1401-1412页

作者： LI YueChen 1,2,3 & HE ChunYang 3 1 college of Geographical Science, Chongqing normal university, Chongqing 400047, china 2 college of Resources and Environmental Science, Chongqing university, Chongqing 400044, china 3 college of Resources Science & Technology, Beijing normal university, Beijing 100875, china college of Geographical Science Chongqing Normal University Chongqing 400047 China college of Resources and Environmental Science Chongqing University Chongqing 400044 China college of Resources Science & Technology Beijing Normal University Beijing 100875 China

Modeling land use/cover scenario changes and its potential impacts on structure and functions of ecosystem in typical regions are helpful to understanding the interactive mechanism between land use/cover system and ecosystem. Based on the analysis of the existing land use/cover simulation and forecast models, a land use/cover scenario dynamics model by the integration of System Dynamics (SD) model, Back Propagation Neural Network (BPNN) and Cellular Automata (CA) model is developed with land use/cover scenario changes in northern china in the next 30 years and simulated in this paper. The model is to simulate the land use/cover scenario demands by using a SD model at first, and then allocating the land use scenario patterns at the local scale with the considerations of land use/cover suitability, inheritance ability and neighborhood effect by using BPNN-CA model to satisfy the balance between land use/cover scenario demands and supplies. It integrates the advantages of SD, BPNN and CA. Macro-driving factors and the micro-spatial pattern are also fully taken into account. The BPNN simplifies the identification of the factors’ weights used in CA model and improves the reliability of the simulation results. The simulation accuracy of the model developed in this paper was found to be about 74%. It suggests that the model has the ability to reflect the complexity of land use/cover system at different scales to some extent and it is a useful tool for assessing the potential impacts of land use system on ecosystem. The simulated results also indicate that the urban land, water area and forest will increase significantly, and farmland and unable land will decrease gradually. Obvious land use/cover changes will take place in the farming-pastoral zone and the southeast area of northern china.

关键词：土地利用中国北方细胞自动机系统动力学

Key technology of mine underground mobile positioning based on LiDAR and coded sequence pattern

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中国有色金属学会会刊：英文版 2011年第S3期21卷 570-576页

作者： WANG Zhi1, 2, WU Li-xin1, 2, LI Hui-ying3 1. college of Resources and Civil Engineering, Northeastern university, Shenyang 110004, china 2. Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs and Ministry of Education, Beijing normal university, Beijing 100875, china 3. college of Computer Science and Technology, jilin university, Changchun 130012, china [a] college of Resources and Civil Engineering Northeastern University Shenyang 110004 China [b] Academy of Disaster Reduction and Emergency Management Ministry of Civil Affairs and Ministry of Education Beijing Normal University Beijing 100875 China [c] college of Computer Science and Technology Jilin University Changchun 130012 China

Technologies of underground mobile positioning were proposed based on LiDAR data and coded sequence pattern landmarks for mine shafts and tunnels environment to meet the needs of fast and accurate positioning and navigation of equipments in the mine underground without satellite navigation signals. A coded sequence pattern was employed for automatic matching of 3D scans. The methods of SIFT feature, Otsu segmentation and fast hough transformation were described for the identification, positioning and interpretation of the coded sequence patterns, respectively. The POSIT model was presented for speeding up computation of the translation and rotation parameters of LiDAR point data, so as to achieve automatic 3D mapping of mine shafts and tunnels. The moving positioning experiment was applied to evaluating the accuracy of proposed pose estimation method from LiDAR scans and coded sequence pattern landmarks acquired in an indoor environment. The performance was evaluated using ground truth data of the indoor setting so as to measure derivations with six degrees of freedom.

关键词： LiDAR coded sequence pattern mobile positioning SLAM algorithm POSIT algorithm

Variation in egg size and nestling growth rate in relation to clutch size and laying sequence in great tits Parus major

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Progress in Natural Science:Materials International 2009年第4期19卷 427-433页

作者： Yuyan You a, Jiang Fenga, Haitao Wangb, Jilong Wang b, Chao Dong b, Xunrui Sub, Hanmei Sunc, Wei Gaob, a Key Laboratory for Wetland Ecology and Vegetation Restoration of National Environmental Protection, Northeast normal university, Changchun 130024, china b college of Life Science, Northeast normal university, No. 5268, Renmin Street, Changchun 130024, china c college of jilin normal university (siping Campus), siping 13.000, china [a]Key Laboratory for Wetland Ecology and Vegetation Restoration of National Environmental Protection Northeast Normal University Changchun 130024 China [b]College of Life Science Northeast Normal University No. 5268 Renmin Street Changchun 130024 China [c]College of Jilin Normal University (Siping Campus) Siping 136000 China

The objectives of this study were to examine (1) optimal clutch size in great tits (Parus major) nesting in nest boxes; (2) variation in egg morphology and nestling growth rate with position in the laying sequence; and (3) hatching asynchrony and nestling survival as determined by infrared nest cameras. We collected data from 73 clutches in artificial nest boxes in the Zuojia Natural Preserve area in jilin Province, china, in 2005 and 2006, using infrared cameras to match laying order to hatching order for four nests. Egg morphology and growth rate were significantly affected by clutch size and position in the laying order. Overall, egg size and growth rate increased with position in the laying order. In general, it was diffcult to detect asynchronous hatching from observations alone, but data from our infrared cameras showed that early-laid eggs tended to hatch before later-laid eggs, leading to hatching asynchrony. However, females invested more into last-laid eggs and nestlings, reducing size asynchrony among the chicks and leading to higher survival rates of nestlings. Our results, therefore, provide support for the "brood survival" hypothesis rather than for the"brood reduction" hypothesis.

关键词： Artificial nest box Infrared camera Egg morphology Laying sequence Hatching asynchrony

Synthesis of three-dimensional hierarchical cobalt hydroxide microstructures

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Science china chemistry 2010年第4期53卷 841-845页

作者： SONG XuChun1, ZHAO Yang2, ZHENG YiFan3, YANG E1 & LIU ZhiSheng1 1Institute of Physical chemistry, Department of chemistry, Fujian normal university, Fuzhou 350007, china 2Department of chemistry, Henan normal university, Xinxiang 453007, china 3college of Chemical Engineering & Materials Science, Zhejiang university of Technology, Hangzhou 310014, china 1. Institute of Physical chemistry Department of Chemistry Fujian Normal University Fuzhou 350007 China2. Department of Chemistry Henan Normal University Xinxiang 453007 China3. College of Chemical Engineering & Materials Science Zhejiang University of Technology Hangzhou 310014 China

β-Co(OH)2 with three-dimensional (3-D) structures was prepared by a simple hydrothermal method. It was found that the amount of cetyltrimethylammonium bromide (CTAB), the pH value, and the reaction time all had an important influence on the formation of this morphology. The products were characterized by X-ray diffraction, energy-dispersive X-ray analysis, and scanning electron microscopy. A possible mechanism of the formation of the 3-D microstructures of β-Co(OH)2 was proposed.

关键词： cobalt hydroxide microstructures hydrothermal

Synthesis, characterization, and biological activities of Pt(Ⅱ) and Pd(Ⅱ2',3',4',5,7-pentahydroxy flavone

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Rare Metals 2004年第1期23卷 38-42页

作者： TANGHui＇An WANGXiaofang YANGSheng WANGLiufang chemistryDepartment TianshuiNormalUniversityTianshui741018.China collegeofchemistryandChemicalEngineering LanzhouUniversityLanzhou730000.China

Pt(Ⅱ) and Pd(Ⅱ) complexes with 2′,3′,4′,5,7-pentahydroxy-flavone weresynthesized and characterized by elemental analysis, molar conductance, IR, ~1HNMR, TG-DTA, UV-Visspectroscopic techniques, and fluorescence analysis. The scavenging effect on the superoxide radical(O_2^-) and the inhibitory effect on lipid peroxides were also investigated. Both the ligand andthe complexes exhibit scavenging effect on superoxide radicals, and the effect of the complexes isgreater than that of the ligand. The Pt(Ⅱ) complex exhibits the strongest scavenging *** Pt(Ⅱ) and Pd(Ⅱ) complexes have the inhibitory effect on lipid peroxides, and the effect ofthe complexes is greater than that of the ligand, but the Pt(Ⅱ) complex has a high effect ofpromoting lipid peroxides.

关键词： inorganic chemistry metal complex 2′,3′,4′,5,7-pentahydroxy-flavone scavenging effect on superoxide radicals inhibitory effect on lipid peroxides

Image space analysis for variational inequalities with cone constraints and applications to traffic equilibria

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Science china Mathematics 2012年第4期55卷 851-868页

作者： LI Jun 1,& HUANG NanJing 2 1 college of Mathematics and Information,china West normal university,Nanchong 637009,china 2 Department of Mathematics,Sichuan university,Chengdu 610064,china 1. college of Mathematics and Information China West Normal University Nanchong 637009 China2. Department of Mathematics Sichuan University Chengdu 610064 China

In this paper,the image space analysis (for short,ISA) is employed to investigate variational in- equalities (for short,VI) with cone *** separation for VI with cone constraints is characterized by using the normal cone to a regularization of the image,and saddle points of the generalized Lagrangian func- ***-type necessary and sufficient optimality conditions for VI with cone constraints are presented by using a separation *** functions and weak sharpness for VI with cone constraints are also investi- ***,the obtained results are applied to standard and time-dependent traffic equilibria introduced by Daniele,Maugeri and Oettli.

关键词： variational inequality image space analysis linear separation necessary and sufficient optimalitycondition traffic equilibrium

A multi-dimensional microcanonical Monte Carlo study of S_0→T_1 intersystem crossing of isocyanic acid

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Science china chemistry 2009年第11期52卷 1885-1891页

作者： ZHANG Feng1,2,FANG WeiHai1,LUO Yi2 & LIU RuoZhuang1 1 college of chemistry,Beijing normal university,Beijing 100875,china 2 Theoretical chemistry,School of Biotechnology,Royal Institute of Technology,S-10691 Stockholm,Sweden 1. college of chemistry Beijing Normal University Beijing 100875 China 2. Theoretical chemistry School of Biotechnology Royal Institute of Technology S-10691 Stockholm Sweden

A general formula for the multi-dimensional Monte Carlo microcanonical nonadiabatic rate constant expressed in configuration space is applied to calculate the rate of intersystem crossing(ISC) between the ground(S0) and first excited triplet(T1) states for isocyanic ***-,two-and three-dimensional potential energy surfaces are constructed by coupled-cluster single-double CCSD calculations,which are used for Monte Carlo *** calculated S0→T1 ISC rate is in good agreement with experimental findings,which gives us a reason to believe that the multi-dimensional Monte Carlo microcanonical nonadiabatic rate theory is a very effective method for calculating nonadiabatic transition rate of a polyatomic molecule.

关键词： multi-dimensional Monte Carlo microcanonical nonadiabatic rate theory intersystem crossing isocyanic acid nonadiabatic transition