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Effect of Annealing Duration and Substrates on Structure and Property of Vanadium Dioxide Films

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Journal of Wuhan University of Technology(Materials Science) 2014年第6期29卷 1117-1123页

作者：储新宏 TAO Haizheng WAN Meinan WANG Shuo NING Zhiyong XU Na 赵修建 State Key Laboratory of Silicate Materials for Architectures (Wuhan University of Technology)

Using the oxidation method from vanadium metal thin films by magnetron sputtering, under the fixed annealing parameters of temperature（400 ℃） and oxygen pressure（103 Pa）, we fabricated a series of vanadium dioxide thin films through the change of annealing durations or substrates（quartz glass or AZOcovered glass）. Characterization of the thermochromic properties together with the X-ray diffraction（XRD） and field emission scanning electron microscopy（FE-SEM） indicates that appropriate annealing duration is a key factor to obtain pure VO2 films and AZO-covered glass is more suitable to obtain the VO2 films with high visible transmittance, good crystallinity and larger near-infrared switching efficiencies（maximum 34% at 2000 nm） compared with the substrate of quartz glass. However, VO2 films on quartz glass exhibit narrower loop（7 ℃） with smart reversible response to temperature. Depth profile XPS spectra further indicate that for the films fabricated on quartz glass from thicker V metal films, the existence of low valence vanadium oxides is inevitable and leads to a lower transmittance in the region of visible light.

关键词： VO2 magnetron sputtering oxidation quartz glass AZO thermal hysteresis loop

Decay parameter and related properties of n-type branching processes

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Science china Mathematics 2012年第12期55卷 2535-2556页

作者： LI JunPing WANG Juan School of Mathematics and Statistics Central South University Changsha 410075 China

We consider decay properties including the decay parameter, invariant measures, invariant vectors, and quasistationary distributions for n-type Markov branching processes on the basis of the 1-type Markov branching processes and 2-type Markov branching processes. Investigating such behavior is crucial in realizing life period of branching models. In this paper, some important properties of the generating functions for n-type Markov branching q-matrix are firstly investigated in detail. The exact value of the decay parameter λC of such model is given for the communicating class C = Zn+ \ 0. It is shown that this λC can be directly obtained from the generating functions of the corresponding q-matrix. Moreover, the λC -invariant measures/vectors and quasi-distributions of such processes are deeply considered. λC -invariant measures and quasi-stationary distributions for the process on C are presented.

关键词： n-type Markov branching process decay parameter invariant measures invariant vectors quasi-stationary distributions

Theoretical investigation of band-gap and mode characteristics of anti-resonance guiding photonic crystal fibres

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Chinese Physics B 2011年第2期20卷 302-310页

作者：苑金辉桑新柱余重秀忻向军张锦龙周桂耀李曙光侯蓝田 Key Laboratory of Information Photonics and Optical Communications (BUPT) Ministry of Education Institute of Optical Communication and Optoelectronics Beijing University of Posts and Telecommunications Institute of Infrared Optical Fibres and Sensors College of Information Science and EngineeringYanshan University

With the full-vector plane-wave method （FVPWM） and the full-vector beam propagation method （FVBPM）, the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in anti- resonance guiding photonic crystal fibres （ARGPCFs） are sufficiently analysed. An ARGPCF operating in the near- infrared wavelength is shown. The influences of the high index cylinders, glass interstitial apexes and silica structure on the characteristics of band-gaps and modes are deeply investigated. The equivalent planar waveguide theory is used for analysing such an ARGPCF filled by the isotropic materials, and the resonance and the anti-resonance characteristics r：~n h~ w~｜] r^r~dlrtpd

关键词： anti-resonance guiding photonic crystal fibres full-vector plane-wave method full-vector beam propagation method band-gap and mode characteristics

Far-zone contributions of airborne gravity anomalies' upward/downward continuation

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Geodesy and Geodynamics 2016年第6期7卷 444-450页

作者： Boyang Zhou Zhicai Luo Yihao Wu Yuqiao Cen Department of Surveying and Mapping Guangdong University of Technology School of Geodesy and Geomatics Wuhan University Center for Urban Science and Progress New York University

Airborne gravimetry has become a vital technique in local gravity field approximation, and upward/downward continuation of gravity data is a key process of airborne gravimetry. In these procedures, the integral domain is divided into two parts, namely the near-zone and the far-zone. The far-zone contributions are approximated by the truncation coefficients and a global geo-potential model, and their values are controlled by several issues. This paper investigates the effects of flight height, the size of near-zone cap, and Remove- Compute-Restore （RCR） technique upon far-zone contributions. Results show that at mountainous area the far-zone contributions can be ignored when EIGEN-6C of 360 degree is removed from the gravity data, together with a near-zone cap of 1°and a flight height less than 10 km, while at flat area EIGEN-6C of 180 degree is feasible.

关键词： Airborne gravimetryPoisson integralUpward/downward continuationFat-zone contdbutionsRemove -Compute -Restoretechnique

Physical-layer secrecy outage of spectrum sharing CR systems over fading channels

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Science china(Information Sciences) 2016年第10期59卷 112-120页

作者： Hequn LIU Hui ZHAO Hong JIANG Chaoqing TANG Gaofeng PAN Tingting LI Yunfei CHEN Chongqing Key Laboratory of Nonlinear Circuits and Intelligent Information Processing Southwest University School of Mathematics and Statistics Southwest University School of Engineering University of Warwick

In this paper, we investigate the physical-layer secrecy outage performance of underlay spectrum sharing systems over Rayleigh and log-normal fading channels in the presence of one eavesdropper. In particular, the secondary transmitter sends data to the legitimate receiver under the constraints of the interference temperature at the primary receiver, while suffering the wiretap from the eavesdropper. Closed-form and approximated expressions are derived for the secrecy outage probability over Rayleigh and log-normal fading channels,respectively. The accuracy of our performance analysis is verified by simulation results.

关键词： spectrum sharing cognitive radio secrecy outage probability Rayleigh fading channels log-normal fading channels

Adsorption of lead on multi-walled carbon nanotubes with different outer diameters and oxygen contents: Kinetics, isotherms and thermodynamics

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Journal of Environmental Sciences 2013年第1期25卷 195-203页

作者： Fei Yu Yanqing Wu Jie Ma Chi Zhang School of Environmental Science and Engineering Shanghai Jiao Tong University State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and EngineeringTongji University

The effects of different outer diameters and surface oxygen contents on the adsorption of heavy metals onto six types of multi-walled carbon nanotubes （MWCNTs） were investigated in an aqueous solution and lead was chosen as a model metal ion. The results indicated that the percentage removal and adsorption capacity of lead remarkably increased with decreasing outer diameter due to larger specific surface area （SSA）. The SSA-normalized maximum adsorption capacity （qJSSA） and SSA-normalized adsorption coefficient （KdSSA） were strongly positively correlated with surface oxygen content, implying that lead adsorption onto MWCNTs significantly increases with the rise of oxygen content and decreases with decreasing SSA. The calculated thermodynamic parameters indicated that adsorption of lead on MWCNTs was endothermic and spontaneous. When the oxygen content of MWCNTs increased from 2.0% to 5.9%, the standard free energy （AGt） became more negative, which implied that the oxygenated functional groups increased the adsorption affinity of MWCNTs for lead. Through calculation of enthalpy （△H0）, AGO and free energy of adsorption （Ea）, lead adsorption onto MWCNTs was recognized as a chemisorption process. The chemical interaction between lead and the phenolic groups of MWCNTs could be one of the main adsorption mechanisms due to highly positive correlations between the phenolic groups and Kd/SSA or qm/SSA.

关键词： adsorption lead multi-walled carbon nanotube diameter surface oxygen content

A novel image encryption scheme based on Keplers third law and random Hadamard transform

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Chinese Physics B 2017年第12期26卷 146-159页

作者：罗玉玲周戎龙刘俊秀丘森辉曹弋 Guangxi Key Laboratory of Multi-Source Information Mining and Security Faculty of Electronic Engineering Guangxi Normal University Guilin 541004 China Guangxi Experiment Center of Information Science Guilin 541004 China Department of Business Transformation and Sustainable Enterprise Surrey Business School University of Surrey Surrey GU2 7XH United Kingdom

In this paper, a novel image encryption scheme based on Keplers third law and random Hadamard transform is proposed to ensure the security of a digital image. First, a set of Kepler periodic sequences is generated to permutate image data, which is characteristic of the plain-image and the Keplers third law. Then, a random Hadamard matrix is constructed by combining the standard Hadamard matrix with the hyper-Chen chaotic system, which is used to further scramble the image coefficients when the image is transformed through random Hadamard transform. In the end, the permuted image presents interweaving diffusion based on two special matrices, which are constructed by Kepler periodic sequence and chaos system. The experimental results and performance analysis show that the proposed encrypted scheme is highly sensitive to the plain-image and external keys, and has a high security and speed, which are very suitable for secure real-time communication of image data.

关键词： Kepler's third law random Hadamard transform interweaving diffusion security

Partial Stability Approach to Consensus Problem of Linear Multi-agent Systems

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自动化学报 2014年第11期40卷 2573-2584页

作者： CHEN Yang-Zhou GE Yan-Rong ZHANG Ya-Xiao College of Electronic Information and Control Engineering Beijing University of Technology Beijing 100124 China College of Physics Science and Information Engineering Hebei Normal University Shijiazhuang 050024 China

A linear transformation is proposed to deal with the consensus problem of high-order linear multi-agent systems (LMASs). In virtue of the linear transformation, the consensus problem is equivalently translated into a partial stability problem. We discuss three issues of the LMASs under a generalized linear protocol: 1) to find criteria of consensus convergence; 2) to calculate consensus function; 3) to design gain matrices in the linear consensus protocol. Precisely, we provide a necessary and sufficient criterion of consensus convergence in terms of Hurwitz stability of a matrix and give an analytical expression of the consensus function. In addition, we set up a relation between the gain matrices in the protocol and the convergence time and consensus accuracy of the agents, and then design the gain matrices with respect to a pre-specified convergence time and a required consensus accuracy.

关键词：线性变换多Agent系统定性方法 Hurwitz稳定性一致性协议增益矩阵收敛时间多代理系统

Predicting a novel pathogenicity island in Helicobacter pylori by genomic barcoding

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World Journal of Gastroenterology 2013年第30期19卷 5006-5010页

作者： Guo-Qing Wang Jian-Ting Xu Guang-Yu Xu Yang Zhang Fan Li Jian Suo Department of Pathogenobiology Norman Bethune Medical College of Jilin University Gastrointestinal Surgery First Hospital of Jilin University Cancer Centre First Hospital of Jilin University

AIM:To apply a new,integrated technique for visualizing bacterial genomes to identify novel pathogenicity islands in Helicobacter pylori(***).METHODS:A genomic barcode imaging method(converting frequency matrices to grey-scale levels)was designed to visually distinguish origin-specific genomic regions in *** complete genome sequences of the six *** strains published in the National Center for Biotechnological Information prokaryotic genome database were scanned,and compared to the genome barcodes of Escherichia coli(***)O157:H7 strain EDL933 and a random nucleotide *** following criteria were applied to identify potential pathogenicity islands(PAIs):(1)barcode distance distinct from that of the general background;(2)length greater than 10000 continuous base pairs;and(3)containing genes with known virulence-related functions(as determined by PfamScan and Blast2GO).RESULTS:Comparison of the barcode images generated for the 26695,HPAG1,J99,Shi470,G27 and P12 *** genomes with those for the *** and random sequence controls revealed that *** genomes contained fewer anomalous *** the *** continuous anomalous regions(longer than 20 kbp in each strain's genome),two fit the criteria for identifying candidate *** bioinformatic-based functional analyses revealed that one of the two anomalous regions was the known pathogenicity island cag PAI,this finding also served as proof-of-principle for the utility of the genomic barcoding approach for identifying PAIs,and characterized the other as a novel PAI,which was designated as ***,the cag-PAI and tfs3-PAI harbored genes encoding type IV secretion system proteins and were predicted to have potential for functional ***:Genomic barcode imaging represents an effective bioinformatic-based approach for scanning bacterial genomes,such as ***,to identify candidate PAIs.

关键词： Helicobacter pylori Genome analysis Pathogenicity islands Genomic bar coding