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A relaxation scheme for a multi-class Lighthill-Whitham-Richards traffic flow model

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第12期10卷 1835-1844页

作者： jian-zhong CheN Zhong-ke SHI Yan-mei HU College of Automation Northwestern Polytechnical University Xi 'an 710072 China College of Science Chang 'an University Xi 'an 710064 China

We present a high-resolution relaxation scheme for a multi-class Lighthill-Whitham-Richards (MCLWR) traffic flow model. This scheme is based on high-order reconstruction for spatial discretization and an implicit-explicit Runge-Kutta method for time integration. The resulting method retains the simplicity of the relaxation schemes. There is no need to involve Riemann solvers and characteristic decomposition. Even the computation of the eigenvalues is not required. This makes the scheme particularly well suited for the MCLWR model in which the analytical expressions of the eigenvalues are difficult to obtain for more than four classes of road users. The numerical results illustrate the effectiveness of the presented method.

关键词： Relaxation scheme Multi-class LWR model Traffic flow CWENO reconstruction Implicit-explicit Runge-Kutta

Algorithm for cavity flow in a new-born goaf and experimental verification

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International Journal of Mining Science and Technology 2023年第3期33卷 351-361页

作者： jian Liu Qichao Zhou Dong Wang Lijun Deng ke Gao College of Safety Science&Engineering Liaoning Technical UniversityHuludao 125105China key Laboratory of Mine Thermo-motive Disaster&Prevention Ministry of EducationHuludao 125105China

Prevention and control measures of spontaneous combustion of coal and gas accumulation in a goaf require an accurate description of its gas flow ***,the commonly used fluid dynamics in porous media is not suitable for the new-born goaf with fracture cavity combination,multi-scale,and large *** this study,we propose a cavity flow algorithm to accurately describe the gas flow state in the new-born *** genetic algorithm(GA)is used to randomly generate the binary matrix of a goaf caving *** difference between the gas flow state calculated by the lattice Boltzmann method(LBM)and the measured data at the boundary or internal measuring points of the real goaf is taken as the GA fitness value,and the real goaf caving shape and the gas flow state are quickly addressed by *** experimental model of new-born goaf is established,and the laser Doppler anemometry(LDA)experiment is carried *** results show that the Jaccard similarity coefficient between the reconstructed caving shape and the real caving shape is 0.7473,the mean square error between the calculated wind speed and the LDA-measured value is 0.0244,and the R2 coefficient is 0.8986,which verify the feasibility of the algorithm.

关键词： Cavity flow Lattice Boltzmann method Laser Doppler anemometry New-born goaf Genetic algorithm

Development of a cable-driven redundant space manipulator with large bending angle by combining quaternion joints and segmented coupled linkages mechanism

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Chinese Journal of Aeronautics 2023年第11期36卷 483-499页

作者： Taiwei YANG jian HUANG Wenfu XU ke SHAO Bin LIANG School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen 518055China State key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China Department of Automation Tsinghua UniversityBeijing 100854China

A cable-driven redundant manipulator has significant potential in confined space applications, such as environmental exploration, equipment monitoring, or maintenance. A traditional design requires 3N driving motors/cables to supply 2N degrees of freedom(DOF) movement *** number of motors is 1.5 times that of the joints’ DOF, increasing the hardware cost and the complexity of the kinematics, dynamics, and control. This study develops a novel redundant space manipulator with decoupled cable-driven joints and segmented linkages. It is a 1680 mm continuum manipulator with eight DOF, consisting of four segmented linkages driven by eight motors/pairs of cables. Each segment has two equivalent DOF, which are realized by four quaternion joints synchronously driven by two linkage cables. The linkage cables of adjacent joints are symmetrically decoupled and offset at 180°. This design allows equal-angle movement of all the joints of each segment. Moreover, each decoupling driving mechanism is designed based on a pulley block composed of two fixed and movable pulleys. The two movable pulleys realize the opposite but equidistant motions of the two driving cables, i.e., pulling and loosening, assuring symmetrical movements of the two driving cables of each segment. Consequently, the equivalent 2N-DOF joints are driven only by 2N motors, significantly reducing the hardware cost and simplifying the mapping relationship between the motor angle/cable length and the joint angle. Furthermore, the bending range of each segment could reach 360°, which is three times that of a traditional design. Finally, a prototype has been developed and experimented with to verify the performance of the proposed mechanism and the corresponding algorithms.

关键词： Cable-driven Mechanism design Redundant manipulators Segmented linkages Kinematics

Snake-Hot-Eye-Assisted Multi-Process-Fusion Target Tracking Based on a Roll-Pitch Semi-strapdown Infrared Imaging Seeker

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Journal of Bionic Engineering 2022年第4期19卷 1124-1139页

作者： jian Chen Zichao Zhang ke Yi Yu Han Zhang Ren College of Engineering China Agricultural UniversityBeijing 100083China key Laboratory of Urban Land Resources Monitoring and Simulation Ministry of Natural ResourcesShenzhen 518000China Systems Engineering Research Institute China State Shipbuilding Corporation LimitedBeijing 100094China College of Water Resources and Civil Engineering China Agricultural UniversityBeijing 100083China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Aiming at intercepting large maneuvering targets precisely,the guidance law of advanced self-seeking missiles requires not only inertial line-of-sight(LOS)angular rate but also target maneuvering ***,the semi-strapdown stabilization platform has lost the ability to measure the inertial LOS angular rate directly,which needs to be extracted by numerical *** differential operation commonly used in traditional methods can magnify the measurement error of the sensor,resulting in insufficient calculation accuracy of the line-of-sight angular *** analyzing the mathematical relationship between the missile-target relative motion and the angle tracking system,a multi-process-fusion integrated filter model of relative motion and angle tracking is *** overcome the defect that the infrared seeker cannot directly measure the missile-target distance,following the snake-hot-eye visual mechanism,a visual bionic imaging guidance method of estimating the missile-target relative distance from the infrared images is proposed to improve the observability of the filter ***,target-tracking simulations verify that the estimation accuracy of target acceleration is improved by four times.

关键词： Roll-pitch semi-strapdown Infrared imaging seeker Target tracking Biological visual mechanism Snake hot eye Integrated filter

A multi-source image fusion algorithm based on gradient regularized convolution sparse representation

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Journal of Systems Engineering and Electronics 2020年第3期31卷 447-459页

作者： WANG jian QIN Chunxia ZHANG Xiufei YANG ke REN Ping School of Electronics and Information Engineering Northwestern Polytechnical UniversityXi’an 710072China No.365 Institute Northwestern Polytechnical UniversityXi’an 710065China

Image fusion based on the sparse representation(SR)has become the primary research direction of the transform domain ***,the SR-based image fusion algorithm has the characteristics of high computational complexity and neglecting the local features of an image,resulting in limited image detail retention and a high registration misalignment *** order to overcome these shortcomings and the noise existing in the image of the fusion process,this paper proposes a new signal decomposition model,namely the multi-source image fusion algorithm of the gradient regularization convolution SR(CSR).The main innovation of this work is using the sparse optimization function to perform two-scale decomposition of the source image to obtain high-frequency components and low-frequency *** sparse coefficient is obtained by the gradient regularization CSR model,and the sparse coefficient is taken as the maximum value to get the optimal high frequency component of the fused *** best low frequency component is obtained by using the fusion strategy of the extreme or the average *** final fused image is obtained by adding two optimal *** results demonstrate that this method greatly improves the ability to maintain image details and reduces image registration sensitivity.

关键词： gradient regularization convolution sparse representation(CSR) image fusion

FIBER ORIENTATION DISTRIBUTIONS IN SLIT CHANNEL FLOWS WITH ABRUPT EXPANSION FOR FIBER SUSPENSIONS

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Journal of Hydrodynamics 2008年第6期20卷 696-705页

作者： KU Xiao-ke LIN jian-zhong State key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China China Jiliang University Hangzhou 310018 China

The lattice Boltzmann method was used to investigate numerically the fiber orientation distributions in slit channel flows with abrupt expansion for fiber suspensions even in the concentrated regime. The channels have a thin slit geometry with 1：4 and 1：3 expansions. Both the interactions between fibers and that between fibers and channel walls were taken into consideration. Some of numerical results are qualitatively in agreement with the experiment data. It is found that most of fibers are aligned in the flow direction in all the suspensions in the entrance region of the expansion. Fiber orientation distributions, having different patterns in different regions of the flow, depend on the expansion ratio of the channel. The mechanical fiber-fiber interaction largely affects the fiber orientation in the downstream of the expansion and in the salient corner for the cases of concentrated suspensions. The hydrodynamic interaction plays an important role on the fiber orientation in the dilute suspension.

关键词： fiber suspension orientation distributions lattice Boltzmann method slit channel flows with abrupt expansion

Optical and electrical properties of InGaZnON thin films

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Chinese Physics B 2020年第1期29卷 475-481页

作者： jian ke Yao Fan Ye Ping Fan Shenzhen key Laboratory of Advanced Thin Films and Applications College of Physics and EnergyShenzhen UniversityShenzhen 518060China

The substrate temperature(Ts)and N2 partial pressure(PN2)dependent optical and electrical properties of sputtered InGaZnON thin films are *** the increased Ts and PN2,the thin film becomes more crystallized and *** Hall mobility,free carrier concentration(Ne),and electrical conductivity increase with the lowered interfacial potential barrier during crystal *** photoluminescence(PL)intensity decreases with the increased *** band gap(Eg)narrows and the linear refractive index(n1)increases with the increasing concentration of N in the thin *** Stokes shift between the PL peak and absorption edge decreases with *** n1,dispersion energy,average oscillator wavelength,and oscillator length strength all increase with *** single oscillator energy decreases with *** nonlinear refractive index and third order optical susceptibility increase with *** Seebeck coefficient,electron effective mass,mean free path,scattering time,and plasma energy are all Ne dependent.

关键词： InGaZnON thin films linear and nonlinear optical properties Seebeck coefficient electron effective mass

Plastic deformation of magnesium alloy with different forming parameters during ultrasonic vibration-assisted single-point incremental forming

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Rare Metals 2022年第11期41卷 3878-3886页

作者： Chun jian Su Ting Ting Xu ke Zhang ke Zhang Shu Mei Lou Qing Wang College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao266590China

The research of forming parameters on the ultrasonic vibration single-point incremental forming of magnesium alloy plastic deformation can provide a theoretical basis for the establishment of the forming *** to the forming characteristics of magnesium alloy sheet,a new method of ultrasonic vibration-as sis ted single-point incremental forming was *** influence of forming parameters on the plastic deformation of magnesium alloy was studied by finite element simulation and *** influence of vibration frequency,amplitude,friction coefficient,and tool head size on stress and thinning rate of magnesium alloy during ultrasonic vibration-as sis ted single-point asymptotic forming was *** results show that the vibration frequency of 20 kHz and forming tool radius of about 5 mm are beneficial for plastic deformation magnesium alloy in ultrasonic vibration-assisted single-point incremental *** vibration amplitude increasing,the maximum shear stress tends to decrease as a whole,but at the amplitude of 0.16 mm,the thinning rate is large and fracture occurs *** friction coefficient increasing,the maximum shear stress tends to increase,and there is a good linear relationship between the maximum thinning rate and the friction coefficient.

关键词： Magnesium alloy Ultrasonic vibration Incremental forming Forming parameters Plastic deformation

Formation mechanism of the graphite-rich protective layer in blast furnace hearths

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International Journal of Minerals,Metallurgy and Materials 2016年第1期23卷 16-24页

作者： ke-xin Jiao jian-liang Zhang Zheng-jian Liu Feng Liu Li-sheng Liang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China State key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China Baoshan Iron & Steel Co. Ltd. Shanghai 200941 China

A long campaign life of blast furnaces is heavily linked to the existence of a protective layer in their hearths. In this work, we conducted dissection studies and investigated damage in blast furnace hearths to estimate the formation mechanism of the protective layer. The results illustrate that a significant amount of graphite phase was trapped within the hearth protective layer. Furthermore, on the basis of the thermodynamic and kinetic calculations of the graphite precipitation process, a precipitation potential index related to the formation of the graphite-rich protective layer was proposed to characterize the formation ability of this layer. We determined that, under normal operating conditions, the precipitation of graphite phase ~om hot metal was thermodynamically possible. Among elements that exist in hot metal, C, Si, and P favor graphite precipitation, whereas Mn and Cr inhibit this process. Moreover, at the same hot-face temperature, an increase of carbon concentration in hot metal can shorten the precipitation time. Finally, the results suggest that measures such as reducing the hot-face tem- perature and increasing the degree of carbon saturation in hot metal are critically important to improve the precipitation potential index.

关键词： blast furnaces hearths graphite protective layers formation mechanisms