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In-situ growth and photoluminescence of β-Ga_2O_3 cone-like nanowires on the surface of Ga substrates

Science china(Technological Sciences) 2009年第6期52卷 1712-1721页

作者： LIU RuiNi1,YANG HeQing1,ZHANG RuiGang1,DONG Hongxing1,CHEN xiaoBo1,LI Li1,ZHANG LiHui1,MA JunHu1 & ZHENG HaiRong2 1 Key Laboratory of Macromolecular Science of shaanxi Province,school of Chemistry and Materials Science,shaanxi normal university,xi’an 71.062.china 2 school of physics & information technology,shaanxi normal university,xi’an 71.062.china 1. Key Laboratory of Macromolecular Science of shaanxi Province School of Chemistry and Materials Science Shaanxi Normal University Xi’an 710062 China 2. school of physics & information technology Shaanxi Normal University Xi’an 710062 China

β-Ga2O3 cone-like nanowires have been in-situ grown on the surface of gallium grains and films by heating gallium substrates at 750-1000℃ for 2h in *** controllable synthesis of β-Ga2O3 nano-wires with different diameters and lengths was achieved by adjusting the heating temperature and *** as-synthesized products were characterized by means of X-ray diffraction,scanning electron mi-croscopy and transmission electron *** results showed that the β-Ga2O3 nanowires are single crystalline with a monoclinic structure and have a controllable diameter and length in the range of 30-100nm and 0.5-1.5μm,respectively.A possible mechanism was also proposed to account for the formation of β-Ga2O3 cone-like *** spectra of the β-Ga2O3 nanowires obtained at different temperatures were measured at room temperature,and a strong blue photolumi-nescence with peaks at 430 and 460nm and a weak red photoluminescence with peak at 713nm were *** blue light emission intensity decreases with increasing the reaction temperature,how-ever,the red light emission intensity hardly *** blue and red light emissions originate from the recombination of an electron on an oxygen vacancy with a hole on a gallium-oxygen vacancy pair and the nitrogen dopants,etc.,respectively.

关键词： β-Ga2O3 cone-like nanowires photoluminescence in-situ growth

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Hydrothermal Synthesis Ultralong Single-crystal Sb_2S_3 Nanowires

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Journal of Wuhan university of technology(Materials Science) 2010年第3期25卷 411-414页

作者：刘运 school of Electric and information Engineering Shaanxi University of Science and Technology

This paper describes an ethylene glycol（EG）-assisted approach to the ultralong Sb2S3 nanowires,formed by a simple hydrothermal reaction between SbCl3 and Na2S in the presence of distilled *** electron microscopy and scanning electron microscopy studies indicate that these Sb2S3 nanowires possess a diameter around 200 nm and length up to 100 μ ***-resolution transmission electron microscopy and selected area electron diffraction studies reveal that each Sb2S3 nanowire is a single-crystal along the [001] *** possible formation mechanism of the nanowires was *** effects of volume ratio of ethylene glycol/water on the morphology of Sb2S3 nanowires were also *** reflectance spectrum result shows that the final products have an apparent blue shift by quantum size effect.

关键词： nanostructures chemical synthesis electron microscopy electron diffraction

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Preparation of Cu-SiO_2 composite aerogel by ambient drying and the influence of synthesizing conditions on the structure of the aerogel

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Chinese Science Bulletin 2011年第7期56卷 685-690页

作者： LI GuiAn, ZHU TingLiang, DENG ZhongXun, ZHANG YaJuan, JIAO Fei & ZHENG HaiRong College of physics and information technology, shaanxi normal university, xi’an 71.062, china College of physics and information technology Shaanxi Normal University

A copper-doped silica composite aerogel with high specific surface area was prepared using a sol-gel method at ambient pressure. A drying control chemical additive (DCCA) N,N-dimethylformamide (DMF) was introduced to the composite sol of tetraethyl orthosilicate (TEOS) and copper nitrate (Cu(NO3)2·3H2O) during the synthesizing process. The influence of the preparation conditions including Cu loading, catalyst concentration and heat treatment on the structure of copper-doped silica was investigated. The results showed that the obtained aerogel particles were uniformly distributed. The pore diameter was in a range of 2 to 15 nm. Heavier Cu loading benefited the formation of CuO crystalline, and reduced the specific surface area and pore diameter. When the catalyst concentration was high, the aggregation of Si-O network was reduced with the increase of it. The composite aerogel exhibited a good thermal stability after the heat treatment at high temperature.

关键词：复合气凝胶铜掺杂凝胶结构合成条件 Si02 常压正硅酸乙酯溶胶凝胶法

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A computational investigation of boron-doped chromium and chromium clusters by density functional theory

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Science china(physics,Mechanics & Astronomy) 2010年第5期53卷 812-817页

作者： GE Guixian1,JING Qun1 & LUO YouHua2,3 1 Key Laboratory of Ecophysics and Department of physics,normal College,Shihezi university,xinjiang 832003,china 2 school of Science,East china university of Science and technology,Shanghai 200237,china 3 Institute of Theoretical physics,school of physics and information Optoelectronics,Henan university,Kaifeng 475004,china 1. Key Laboratory of Ecophysics and Department of physics Normal College Shihezi University Xinjiang 832003 China2. School of Science East China University of Science and Technology Shanghai 200237 China3. Institute of Theoretical Physics School of Physics and Information Optoelectronics Henan University Kaifeng 475004 China

The geometries,stabilities and electronic properties of Crn and CrnB(n=2-9) clusters have been systematically investigated by density functional *** results suggest that the lowest energy structures for CrnB clusters can be obtained by substituting one Cr atom in Crn+1 clusters with B *** geometries of CrnB clusters are similar to that of Crn+1 clusters except for local structural *** second-order difference and fragmentation energy show Cr4,Cr6,Cr8,Cr3B,Cr5B and Cr8B cluster are the most stable among these studied *** impurity B increases the stabilities of chromium *** B is doped on the Crn clusters,cluster geometry does dominate positive role in enhancing their *** doped B atom does not change the coupling way of the Cr site in Crn clusters,but breaks the symmetry and the Cr atoms are no longer *** doped B atom increases the total magnetic moments of Crn in most cases.

关键词： Crn and CrnB clusters geometries electronic properties

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Linearly time-varying channel estimation and training power allocation for OFDM/MIMO systems using superimposed training

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Science china(information Sciences) 2011年第7期54卷 1456-1470页

作者： ZHANG Han 1,DAI xianHua 2 & Pan DaRu 1 1 school of physics and Telecommunication Engineering,South china normal university,Guangzhou 510006,china 2 Department of information Science and technology,SUN Yat-sen university,Guangzhou 510026,china 1. school of physics and Telecommunication Engineering South China Normal University Guangzhou 510006 China2. Department of Information Science and Technology SUN Yat-sen University Guangzhou 510026 China

We address the problem of estimating the linearly time-varying (LTV) channel of orthogonal frequency division multiplexing (OFDM)/multiple-input multiple-output (MIMO) systems using superimposed training (ST).The LTV channel is modeled by truncated discrete Fourier *** on this model,a two-step approach is adopted to estimate the LTV channel over multiple OFDM *** also present performance analysis of the channel estimation and derive a closed-form expression for the channel estimation *** is shown that the estimation variances,unlike that of the conventional ST-based schemes,approach to a fixed lower-bound as the training length increases,which is directly proportional to information-pilot power *** wireless communication systems with a limited transmission power,we optimize the ST power allocation by maximizing the lower bound of the average channel *** results show that the proposed approach outperforms the frequency-division multiplexed training schemes.

关键词： OFDM/MIMO systems linearly time-varying channel estimation superimposed training training power allocation

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(2,n)secret sharing scheme for gray and color images based on Boolean operation

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Science china(information Sciences) 2012年第5期55卷 1151-1161页

作者： DONG Lin 1,WANG DaoShun 1,LI ShunDong 2 & DAI YiQi 1 1 Department of Computer Science and technology,Tsinghua university,Beijing 100084,china 2 school of Computer Science,shaanxi normal university,xi'an 71.062.china 1. Department of Computer Science and technology Tsinghua University Beijing 100084 China2. School of Computer Science Shaanxi Normal University Xi’an 710062 China

Traditional secret sharing (SS) schemes can reconstruct the secret precisely,but have high com-putation *** secret sharing (VSS) schemes use human visual system to reconstruct the secret without cryptographic computation,but have pixel expansion and loss of *** et *** a (2,n)-SS scheme for binary images based on Boolean operation,which has low computation complexity,no pixel expansion and the contrast is 1/*** this paper,we first construct an r runs (2,n)-SS scheme to improve the contrast of Wang et al.'s binary (2,n)-SS *** we present two approaches to construct r runs (2,n)-SS schemes for grayscale image and color *** two approaches are both based on Boolean operation,while one approach uses halftone technology and the other uses bit level *** proposed schemes have low computation complexity and almost ideal contrast.

关键词： secret sharing scheme Boolean operation halftone contrast

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Refractive index changes induced by sheet beams with various intensity distributions in LiNbO_(3):Fe crystal

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Science china(physics,Mechanics & Astronomy) 2005年第4期48卷 399-412页

作者： ZHANG Peng1, ZHAO Jianlin1, XU Honglai1, SUN Yidong2, YANG Dexing1 & WANG Meirong1 1. Institute of Optical information Science and technology, school of Science, Northwestern Polytechnical university, xi’an 710072, china 2. school of Science, xi’an Jiaotong university, xi’an 710049, china 1. Institute of Optical information Science and Technology School of Science Northwestern Polytechnical University 710072 Xi’an China 2. school of Science Xi’an Jiaotong University 710049 Xi’an China

According to the Kukhtarev equations and a simplified model based on the photovoltaic charge carriers transport mechanism, the distributions of the index changes (DICs) in LiNbO3:Fe crystals induced by sheet beams with various intensity profiles are theoretically analyzed. The numerically simulated results coincide with the analytic expressions deduced from the simplified model. The DICs in a LiNbO3:Fe crystal induced by sheet beams with rectangular, Gaussian and square law profiles are measured by using the interferometric method. By employing the analytic expressions, the experimental data points are well fitted. By utilizing the angular spectrum theory and the ray equation, the uniformities of the intensity profiles of the writing beams along the propagation directions and the influences of the self-defocusing effect of the crystal are numerically simulated, respectively. The results show that the experimental results are reliable. The numerically simulated method and the analytic expressions can be both employed to predict the DICs induced by sheet beams with various light intensity profiles. Furthermore, utilizing writing beams with proper intensity profiles, any desired index distributions could be obtained.

关键词： LiNbO3:Fe crystal, light intensity profile, distribution of refractive index changes, sheet beam.

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Tunneling conductance in graphene ferromagnet/p wave superconductor junctions

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Science china(physics,Mechanics & Astronomy) 2012年第4期Mechanics & Astronomy) .卷 649-653页

作者： LI xiaoWei 1,2*,CHEN HuaBao 1 & LIU ShuJing 1 1 school of physics and Electronic Electrical Engineering,Huaiyin normal university,Huaian 223300,china 2 State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and information technology,Chinese Academy of Sciences,Shanghai 200050,china 1. school of physics and Electronic Electrical Engineering Huaiyin Normal University Huaian 223300 China2. State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 China

Using the extended Blonder-Tinkham-Klapwijk formalism,we investigate the conductance spectra of graphene ferromagnet/p wave superconductor *** is found that the conductance spectra are affected by the p wave pairing *** ferromagnetic exchange energy in the ferromagnet can suppress Andreev retroreflection but enhance the specular Andreev reflection in graphene ferromagnet/p wave superconductor *** conductance decreases with increasing exchange energy Eh for EhEF.

关键词： graphene ferromagnet p wave superconductor tunneling conductance

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(Pb_(0.97)La_(0.02))(Zr_(0.65)Sn_(0.35-x)Ti_x)O_3反铁电陶瓷的热膨胀性质

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物理学报 2003年第9期52卷 2314-2318页

作者：刘鹏徐卓姚熹陕西师范大学物理学与信息技术学院西安710062 西安交通大学电子材料研究所西安710049

在 - 10 0— 2 0 0℃温度范围内 ,测量了 (Pb0 .97La0 .0 2 ) (Zr0 .6 5Sn0 .35-xTix)O3(PZST ,0 1≤x≤ 0 14 )反铁电陶瓷的热膨胀性质 .实验结果表明 ,组分在 0 1≤x≤ 0 12的试样室温下为反铁电 (AFEt)四方相 ,热膨胀系数 (α)... 详细信息

在 - 10 0— 2 0 0℃温度范围内 ,测量了 (Pb0 .97La0 .0 2 ) (Zr0 .6 5Sn0 .35-xTix)O3(PZST ,0 1≤x≤ 0 14 )反铁电陶瓷的热膨胀性质 .实验结果表明 ,组分在 0 1≤x≤ 0 12的试样室温下为反铁电 (AFEt)四方相 ,热膨胀系数 (α)在低温段发生“弯曲” ,而变温x射线衍射谱 (XRD)显示材料保持四方相结构 ;当Ti含量在 0 12 5≤x≤ 0 14时 ,室温下是铁电三方相 (FER) ,温度升高时FER →AFEt 相变体积收缩 ,AFEt→立方顺电 (PEc)相变体积增大 ;变温XRD谱证明了材料相结构随温度的转变过程 .用多元复杂化合物存在纳米线度组分非均匀的观点解释了热膨胀性质随Ti含量演化的物理机理 ,并得到了该系统的温度 Ti(x)

关键词：热膨胀性质铁电/反铁电相界反铁电陶瓷 PZST (Pb0.97La0.02)(Zr0.65Sn0.35-xTix)O3

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Level Set interface treatment and its application in Euler method

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 227-236页

作者： WU KaiTeng1,2,HAO Li3,WANG Cheng4 & ZHANG Li1,2 1 Numerical Simulation Sichuan Higher school Key Laboratory,Neijiang normal university,Neijiang 641112,china 2 College of Mathematics and information Science,Neijiang normal university,Neijiang 641112,china 3 College of Science,Beijing university of Civil Engineering and Architecture,Beijing 100044,china 4 State Key Laboratory of Explosion Science and technology,Beijing Institute of technology,Beijing 100081,china 1. Numerical Simulation Sichuan Higher school Key Laboratory Neijiang Normal University Neijiang 641112 China2. College of Mathematics and Information Science Neijiang Normal University Neijiang 641112 China3. College of Science Beijing University of Civil Engineering and Architecture Beijing 100044 China4. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

Level Set interface treatment method is introduced into Euler method,which is employed for interface treatment method for multi-materials. Combined with the ghost fluid method,the moving interface is tracked. Fifth-order WENO spatial discretization and third-order TVD Runge-Kutta time discretization methods are used. Shock-wave action on bubble,implosion and velocity field Shock effect bubbles; implosion and velocity field are simulated by means of LS-MMIC3D programmed by C++. Nu-merical results show that the Level Set interface treatment method is effective and feasible for multi-material interface treatment in comparison with the WENO method.

关键词： Euler method Level Set method shock-wave action on bubble implosion numerical simulation

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