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Root imaging from ground penetrating radar data by CPSO-OMP compressed sensing

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Journal of Forestry Research 2017年第1期28卷 155-162页

作者： Chao Li Yaowen Su Yizhuo Zhang Huimin Yang Northeast Forestry University Harbin 150040People's Republic of China

As the amount of data produced by ground penetrating radar （GPR） for roots is large, the transmission and the storage of data consumes great resources. To alleviate this problem, we propose here a root imaging algorithm using chaotic particle swarm optimal （CPSO） compressed sensing based on GPR data according to the sparsity of root space. Radar data are decomposed, observed, measured and represented in sparse manner, so roots image can be reconstructed with limited data. Firstly, radar signal measurement and sparse representation are implemented, and the solution space is established by wavelet basis and Gauss random matrix; secondly, the matching function is considered as the fitness function, and the best fitness value is found by a PSO algorithm; then, a chaotic search was used to obtain the global optimal operator; finally, the root image is reconstructed by the optimal operators. A-scan data, B-scan data, and complex data from American GSSI GPR is used, respectively, in the experimental test. For B-scan data, the computation time was reduced 60 % and PSNR was improved 5.539 dB; for actual root data imaging, the reconstruction PSNR was 26.300 dB, and total computation time was only 67.210 s. The CPSO-OMP algorithm overcomes the problem of local optimum trapping and comprehensively enhances the precision during reconstruction.

关键词： Chaotic particle swarm Compression sensing Ground penetrating radar Orthogonal matching pursuit (OMP) Root imaging

Image encryption based on a novel memristive chaotic system,Grain-128a algorithm and dynamic pixel masking

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Journal of Systems Engineering and Electronics 2022年第3期33卷 534-550页

作者： HUANG Lilian SUN Yi XIANG Jianhong WANG Linyu College of Information and Communication Engineering Harbin Engineering UniversityHarbin 150001China Key Laboratory of Advanced Marine Communication and Information Technology-Ministry of Industry and Information Technology Harbin Engineering UniversityHarbin 150001China

In this paper,we first propose a memristive chaotic system and implement it by circuit *** chaotic dynamics and various attractors are analysed by using phase portrait,bifurcation diagram,and Lyapunov *** particular,the system has robust chaos in a wide parameter range and the initial value space,which is favourable to the security communication ***,we further explore its application in image encryption and present a new *** image processing,the external key is protected by the Grain-128a algorithm and the initial values of the memristive system are updated with the plain *** not only perform random pixel extraction and masking with the chaotic cipher,but also use them as control parameters for Brownian motion to obtain the permutation *** addition,multiplication on the finite field GF(2^(8))is added to further enhance the ***,the simulation results verify that the proposed image encryption scheme has better performance and higher security,which can effectively resist various attacks.

关键词： memristive chaotic system super-wide parameter range image encryption Grain-128a algorithm dynamic pixel masking

Synthesis, Crystal Structure and Thermal Property of a Manganese(II) 4-Carboxyphenoxyacetate Complex

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Chinese Journal of Structural Chemistry 2005年第3期24卷 334-338页

作者：霍丽华高山刘继伟谷长生赵辉赵经贵 SchoolofChemistryandMaterialsscience HeilongjiangUniversityHarbin150080China

The manganese(II) complex, [Mn(phen)2(4-CPOA)(H2O)]?5H2O (4-CPOAH2 = 4- carboxyphenoxyacetic acid) has been synthesized and characterized by elemental analyses, IR, TG and single-crystal X-ray diffraction. The crystal is of monoclinic, space group C2/c, with a = 27.471(3), b = 18.490(4), c = 14.507(3) ?, β = 115.13(3)o, V = 6671(3) ?3, Z = 8, Mr = 717.58, Dc= 1.429 g/cm3, μ = 0.462 mm–1, F(000) = 2984, the final R = 0.0535 and wR = 0.1200 for 5413 observed reflections with I > 2σ(I). The Mn(II) atom is coordinated by one O atom of 4-carboxy- phenoxyacetate, four N atoms of two 1,10-phenanthroline and one water molecule, residing in a distorted octahedral environment. A supramolecular network structure is formed by hydrogen bonds and π-π stacking interactions.

关键词： manganese (II) carboxylate complex crystal structure thermal property

Propagation of Thermo-Elastic Waves at Several Typical Interfaces Based on the Theory of Dipolar Gradient Elasticity

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Acta Mechanica Solida Sinica 2018年第2期31卷 229-242页

作者： Yueqiu Li Peijun Wei Department of Mathematics Qiqihar University Department of Applied Mechanics University of Science and Technology Beijing

The reflection and transmission properties of thermo-elastic waves at five possible interfaces between two different strain gradient thermo-elastic solids are investigated based on the generalized thermo-elastic theory without energy dissipation （the GN theory）. First, the function of free energy density is postulated and the constitutive relations are defined. Then, the temperature field and the displacement field are obtained from the motion equation in the form of displacement and the thermal transport equation without energy dissipation in the strain gradient thermo-elastic solid. Finally, the five types of thermo-elastic interracial conditions are used to calculate the amplitude ratios of the reflection and transmission waves with respect to the incident wave. Further, the reflection and transmission coefficients in terms of energy flux ratio are calculated and the numerical results are validated by the energy conservation along the normal direction. It is found that there are five types of dispersive waves, namely the coupled longitudinal wave （the CP wave）, the coupled thermal wave （the CT wave）, the shear wave, and two evanescent waves （the coupled SP wave and SS wave）, that become the surface waves at an interface. The mechanical interfacial conditions mainly influence the coupled CP waves, SV waves, and surface waves, while the thermal interracial conditions mainly influence the coupled CT waves.

关键词： Gradient elasticity Thermo-elasticity Interfacial condition Reflection Transmission

VSe_(2)/V_(2)C heterocatalyst with built-in electric field for efficient lithium-sulfur batteries:Remedies polysulfide shuttle and conversion kinetics

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Journal of Energy Chemistry 2024年第2期89卷 397-409,I0010页

作者： Yanwei Lv Lina Bai Qi Jin Siyu Deng Xinzhi Ma Fengfeng Han Juan Wang Lirong Zhang Lili Wu Xitian Zhang Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025HeilongjiangChina

Lithium sulfur(Li-S)battery is a kind of burgeoning energy storage system with high energy ***,the electrolyte-soluble intermediate lithium polysulfides(Li PSs)undergo notorious shuttle effect,which seriously hinders the commercialization of Li-S ***,a unique VSe_(2)/V_(2)C heterostructure with local built-in electric field was rationally engineered from V_(2)C parent via a facile thermal selenization *** exquisitely synergizes the strong affinity of V_(2)C with the effective electrocatalytic activity of VSe_(2).More importantly,the local built-in electric field at the heterointerface can sufficiently promote the electron/ion transport ability and eventually boost the conversion kinetics of sulfur *** Li-S battery equipped with VSe_(2)/V_(2)C-CNTs-PP separator achieved an outstanding initial specific capacity of 1439.1 m A h g^(-1)with a high capacity retention of 73%after 100 cycles at0.1 *** impressively,a wonderful capacity of 571.6 mA h g^(-1)was effectively maintained after 600cycles at 2 C with a capacity decay rate of 0.07%.Even under a sulfur loading of 4.8 mg cm^(-2),areal capacity still can be up to 5.6 m A h cm^(-2).In-situ Raman tests explicitly illustrate the effectiveness of VSe_(2)/V_(2)C-CNTs modifier in restricting Li PSs *** with density functional theory calculations,the underlying mechanism of VSe_(2)/V_(2)C heterostructure for remedying Li PSs shuttling and conversion kinetics was *** strategy of constructing VSe_(2)/V_(2)C heterocatalyst in this work proposes a universal protocol to design metal selenide-based separator modifier for Li-S ***,it opens an efficient avenue for the separator engineering of Li-S batteries.

关键词： Li-S battery Shuttle effect Separator modifier VSe_(2)/V_(2)C heterostructure Built-in electric field

Double effects of recrystallization behavior on grain morphology evolution and mechanical properties of Al/Mg/Al composite plate by hard plate rolling

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Progress in natural science:Materials International 2024年第5期34卷 1029-1038页

作者： Jia Yang Zhang Feng Li Fu Wei Kang Zi Yi Wang Lu Sun School of Materials science and Chemical Engineering Harbin University of Science and Technology Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology heilongjiang Provincial Key Laboratory of Light Metal Materials Modification & Green Forming Technology Harbin University of Science and Technology

Enhancing the bonding strength, optimizing the microstructure and refining the properties represent effective strategies for the fabrication of heterogeneous composite plates. In this study, composite plates of Al/Mg/Al were fabricated through hard plate rolling(HPR) with a reduction in rolling ranging from 40 % to 80 %. The research primarily concentrates on the substrate in the influence of rolling dynamic recrystallization(DRX) behavior on the grain morphology evolution and mechanical properties of AZ31 magnesium alloy sheets during the process. The findings indicate that at a compression amount of 60 %, the composite plate exhibits an ultimate tensile strength(UTS), a maximum elongation(EL) of 12.5 %, and improved interface bonding. Comparative analysis reveals the occurrence of DRX on the Mg side, resulting in the formation of small DRXed grains being generated. With an increase in reduction, DRX is facilitated, leading to an initial rise and subsequent decline in the proportion of DRXed grains. The proliferation of fine grains hinder dislocation movement, thereby reinforcing composite ***, an elevation in the degree of recrystallization enhances the initiation of non-basal slip and enhances the plasticity of sheet metal. This study offers valuable scientific guidance and technical assistance for the production of forming high-quality Mg–Al composite plates.

关键词： Al/Mg/Al Composite plate Dynamic recrystallization Hard plate rolling Mechanical properties

Seed-Oriented Local Community Detection Based on Influence Spreading

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Computer Modeling in Engineering & sciences 2022年第7期132卷 215-249页

作者： Shenglong Wang Jing Yang Xiaoyu Ding Jianpei Zhang Meng Zhao College of Computer science and Technology Harbin Engineering UniversityHarbin150001China College of Computer science and Technology Chongqing University of Posts and TelecommunicationsChongqing400065China

In recent years,local community detection algorithms have developed rapidly because of their nearly linear computing time and the convenience of obtaining the local information of real-world ***,there are still some issues that need to be further ***,there is no local community detection algorithm dedicated to detecting a seed-oriented local community,that is,the local community with the seed as the *** second and third issues are that the quality of local communities detected by the previous local community detection algorithms are largely dependent on the position of the seed and predefined parameters,*** solve the existing problems,we propose a seed-oriented local community detection algorithm,named SOLCD,that is based on influence ***,we propose a novel measure of node influence named k-core centrality that is based on the k-core value of adjacent ***,we obtain the seed-oriented local community,which is composed of the may-members and the must-member chain of the seed,by detecting the influence scope of the *** may-members and the must-members of the seed are determined by judging the influence relationship between the node and the *** state-of-art algorithms are compared to SOLCD on six real-world networks and three groups of artificial *** experimental results show that SOLCD can achieve a high-quality seed-oriented local community for various real-world networks and artificial networks with different *** addition,when taking nodes with different influence as seeds,SOLCD can stably obtain high-quality seed-oriented local communities.

关键词： Complex network local community detection influence spreading seed-oriented degree centrality k-core centrality local expansion

Synergistic strengthening mechanism of gradient structure AZ31 magnesium alloy plate in hard plate rolling

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Progress in natural science:Materials International 2023年第5期33卷 652-659页

作者： Wen Tao Niu Feng Li Jia Yang Zhang Chao Li Lu Sun School of Materials science and Chemical Engineering Harbin University of Science and Technology Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology heilongjiang Provincial Key Laboratory of Light Metal Materials Modification & Green Forming Technology Harbin University of Science and Technology

Compared with homogeneous structural materials, gradient structural materials are easier to realize the strengthductility optimization. Research on the strengthening mechanism of different gradient structure materials is a meaningful way to broaden the application of gradient structure materials. In this paper, the AZ31 magnesium alloy plate was rolled by hard plate rolling. The gradient structure was controlled by changing the initial plate thickness. When the initial plate thickness was 4 mm, AZ31 magnesium alloy shows excellent strength and ductility, the tensile strength was 282.2 MPa, and the ductility was 28.4 %. The change of the initial plate thickness changes the stress state which forming a gradient structure with different characteristic layers. The extra strengthening between different characteristic layers improves the properties of gradient structure, which makes the magnesium alloy change from a uniaxial stress state to a multi-axial stress state during the tensile process. The increase of the characteristic layer induces more geometrically necessary dislocation accumulation, improving the gradient structure's strength and ductility. This research provides a new design strategy for the forming and performance optimization of gradient structure magnesium alloy plate by hard plate rolling, which has good industrial production and application potential.

关键词： Hard plate rolling Gradient structure AZ31 magnesium alloy Extra strengthening Geometrically necessary dislocation

Observer-based multivariable fixed-time formation control of mobile robots

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Journal of Systems Engineering and Electronics 2020年第2期31卷 403-414页

作者： LI Yandong ZHU Ling and GUO Yuan College of Computer and Control Engineering Qiqihar UniversityQiqihar 161006China School of Mechanical and Electronic Engineering Qiqihar UniversityQiqihar 161006China

This paper proposes a multivariable fixed-time leaderfollower formation control method for a group of nonholonomic mobile robots, which has the ability to estimate multiple uncertainties. Firstly, based on the state space model of the leader-follower formation, a multivariable fixed-time formation kinematics controller is designed. Secondly, to overcome uncertainties existing in the nonholonomic mobile robot system, such as load change,friction, external disturbance, a multivariable fixed-time torque controller based on the fixed-time disturbance observer at the dynamic level is designed. The designed torque controller is cascaded with the formation controller and finally realizes accurate estimation of the uncertain part of the system, the follower tracking of reference velocity and the desired formation of the leader and the follower in a fixed-time. The fixed-time upper bound is completely determined by the controller parameters, which is independent of the initial state of the system. The multivariable fixed-time control theory and the Lyapunov method are adopted to ensure the system ***, the effectiveness of the proposed algorithm is verified by the experimental simulation.

关键词： multivariable fixed-time control formation control uncertainty fixed time observer nonholonomic mobile robot