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State-chain sequential feedback reinforcement learning for path planning of autonomous mobile robots

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第3期14卷 167-178页

作者： Xin MA Ya XU Guo-qiang SUN li-xia DENG yi-bin li School of Control Science and Engineering Shandong University

This paper deals with a new approach based on Q-learning for solving the problem of mobile robot path planning in complex unknown static *** a computational approach to learning through interaction with the environment,reinforcement learning algorithms have been widely used for intelligent robot control,especially in the field of autonomous mobile ***,the learning process is slow and *** practical applications,rapid rates of convergence are *** at the problem of slow convergence and long learning time for Q-learning based mobile robot path planning,a state-chain sequential feedback Q-learning algorithm is proposed for quickly searching for the optimal path of mobile robots in complex unknown static *** state chain is built during the searching *** one action is chosen and the reward is received,the Q-values of the state-action pairs on the previously built state chain are sequentially updated with one-step *** the increasing number of Q-values updated after one action,the number of actual steps for convergence decreases and thus,the learning time decreases,where a step is a state *** simulations validate the efficiency of the newly proposed approach for mobile robot path planning in complex *** results show that the new approach has a high convergence speed and that the robot can find the collision-free optimal path in complex unknown static environments with much shorter time,compared with the one-step Q-learning algorithm and the Q(λ)-learning algorithm.

关键词： Path planning Q-learning Autonomous mobile robot Reinforcement learning

Influence of Backbone and Axial Substituent of Catalyst onα-Imino-ketone Nickel Mediated Ethylene(Co)Polymerization

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Chinese Journal of Polymer Science 2022年第5期40卷 469-477页

作者： Yu-Kai Chu xiao-Qiang Hu Yue Zhang Da-Jun liu yi-Xin Zhang Zhong-Bao Jian College of Chemistry and Environmental Engineering Changchun University of Science and TechnologyChangchun 130022China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 730022China

Theα-imino-ketone nickel catalyst is an emerging versatile platform that is easy to prepare and allows for the production of branched high molecular weight functionalized ***,study on this catalyst system is rare thus *** this contribution,by introducing different backbones,flexible and rigid axial substituents into theα-imino-ketone framework,a family of cationic nickel catalysts were synthesized and fully *** the addition of any activator,systematic studies on ethylene polymerization and copolymerization with polar monomers were performed to explore the influence of both backbone and axial substituent on catalytic activity,polymer molecular weight,branching density and *** particular,owing to the unique semi-opening feature of theα-imino-ketone framework,the preferred nickel catalyst exhibited high activity of 175 kg·mol^(-1)·h^(-1)to produce functionalized polyethylene with molecular weight of 13.4 kg·mol^(-1)and comonomer incorporation of 2.9 mol%.

关键词： Olefin polymerization α-Imino-ketone ligand Nickel catalyst Polar monomer

2D multifunctional devices:from material preparation to device fabrication and neuromorphic applications

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International Journal of Extreme Manufacturing 2024年第3期6卷 91-118页

作者： Zhuohui Huang Yanran li yi Zhang Jiewei Chen Jun He Jie Jiang Hunan Key Laboratory of Nanophotonics and Devices School of PhysicsCentral South UniversityChangshaHunanPeople’s Republic of China Department of Applied Physics The Hong Kong Polytechnic UniversityHong Kong Special Administrative Region of ChinaPeople’s Republic of China

Neuromorphic computing systems,which mimic the operation of neurons and synapses in the human brain,are seen as an appealing next-generation computing method due to their strong and efficient computing ***-dimensional (2D) materials with dangling bond-free surfaces and atomic-level thicknesses have emerged as promising candidates for neuromorphic computing *** a result,2D neuromorphic devices may provide an ideal platform for developing multifunctional neuromorphic ***,we review the recent neuromorphic devices based on 2D material and their multifunctional *** synthesis and next micro–nano fabrication methods of 2D materials and their heterostructures are first *** recent advances of neuromorphic 2D devices are discussed in detail using different operating *** importantly,we present a review of emerging multifunctional neuromorphic applications,including neuromorphic visual,auditory,tactile,and nociceptive systems based on 2D *** the end,we discuss the problems and methods for 2D neuromorphic device developments in the *** paper will give insights into designing 2D neuromorphic devices and applying them to the future neuromorphic systems.

关键词： 2D material micro–nano fabrication multifunctional system neuromorphic electronics artificial intelligence

Designing a Phthalonitrile/Benzoxazine Blend for the Advanced GFRP Composite Materials

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Chinese Journal of Polymer Science 2018年第1期36卷 106-112页

作者： Xu-lin Yang Kui li Ming-Zhen Xu xiao-Bo liu Research Branch of Functional Materials Institute of Microelectronic & Solid State Electronic University of Electronic Science and Technology of China

High performance resin must be used in the high performance glass fiber-reinforced plastic（GFRP） composites, but it is sometimes difficult to balance the processabilities and the final properties in the design of advanced thermoset GFRP composites. In this study, a phthalonitrile/benzoxazine（PPN/BZ） blend with excellent processability has been designed and applied in the GFRP composite materials. PPN/BZ blend with good solubility, low melt viscosity, appropriate gel condition and low-temperature curing behavior could enable their GFRP composite preparation with the prepreg-laminate method under a relatively mild condition. The resulted PPN/BZ GFRP composites exhibit excellent mechanical properties with flexural strength over 700 MPa and flexural modulus more than 19 GPa. Fracture surface morphologies of the PPN/BZ GFRP composites show that the interfacial adhesion between resin and GF is improved. The temperatures at weight loss 5%（T_（5%）） and char residue at 800 °C of all PPN/BZ GFRP composites are over 435 °C and 65% respectively. PPN/BZ GFRP composites with high performance characteristics may find applications under some critical circumstances with requirements of high mechanical properties and high service temperatures.

关键词： Phthalonitrile Benzoxazine High performance composite GFRP composites

Modeling and analyzing point cloud generation in missile-borne liDAR

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Defence Technology（防务技术） 2020年第1期16卷 69-76页

作者： Min-le li yi-hua Hu Nan-xiang Zhao Qi-shu Qian State Key Laboratory of Pulsed Power Laser Technology College of Electronic EngineeringNational University of Defense TechnologyHefei230037China Anhui Province Key Laboratory of Electronic Restriction Technology Hefei230037China

The missile-borne liDAR has an essential prospect in precise ***,the instability of the missile has a significant impact on the precision of liDAR point cloud,thus modeling and analyzing the influencing factors of point cloud generation is *** this investigation,the authors modeled the point cloud calculation process of missile-borne linear array scanning liDAR under ideal conditions and analyzed the effect of position change on the fleld of view(FOV) in the course of platform ***,the authors summarized that the stability concerning the field of view and the target tracking are dependent on three limiting ***,the authors derived an error formula and analyzed several typical errors in missile platform flight,including scanner error,POS error,system integration error,and platform vibration *** on theo retical analysis and simulation experiments,the model proposed in this papier can provide a theoretical basis for the design of the missile-borne liDAR system and the selection of related instruments in practice.

关键词： liDAR Point cloud Precise guidance Vibration

A New Structure of Cooling Wall Tube for Supercritical CO_(2)Coal-Fired Power Plants

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Journal of Thermal Science 2023年第3期32卷 1239-1250页

作者： WANG Yanjuan GAO Shuo JIANG Qiongqiong li yi liU Qibin XU Jinliang The Beijing Key Laboratory of Multiphase Flow and Heat Transfer North China Electric Power UniversityBeijing 102206China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

In terms of developing supercritical CO_(2)(sCO_(2))coal-fired power plants,enhancing cooling wall performance is one of significant factors to improve system *** this paper,a new cooling wall tube structure is proposed to match the non-uniform heat flux(NUH)with the thermal resistance by changing the cooling wall tube eccentricity.A three-dimensional multi-physical coupling model of cooling wall is constructed to compare the novel structure to the conventional *** properties of fluid dynamics,thermal stress,coupled heat transfer and cooling wall deformation are *** contrast to the traditional structure,the maximum temperature and circumferential temperature difference(CTD)of the proposed structure can be reduced by 2%and 27.4%,*** essential working parameters related to the performances of the cooling wall tube are *** maximum temperature of the new structure is reduced by 8-13 K and the maximum thermal stress is reduced by about 10%-15%under all the simulated working conditions when the eccentricity changes from 0 to *** proposed structure can effectively reduce the maximum temperature and circumferential temperature gradient under ***,a novel insight is put out for the design and optimization of the cooling wall tube in coal-fired power plants.

关键词： supercritical carbon dioxide cooling wall tube thermal-hydraulic structural coupling supereritical heat transfer

A CLASS OF TWO-STEP CONTINUITY RUNGE-KUTTA METHODS FOR SOLVING SINGULAR DELAY DIFFERENTIAL EQUATIONS AND ITS STABIliTY ANALYSIS

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Journal of Computational Mathematics 2005年第6期23卷 647-656页

作者： Xin Leng De-gui liu xiao-qiu Song li-rong Chen Beijing Institute of Computer Application and Simulation Technology 100854 China Beijing Institute of Applied Physics and Computational Mathematics 100088 China

In this paper, a class of two-step continuity Runge-Kutta（TSCRK） methods for solving singular delay differential equations（DDEs） is presented. Analysis of numerical stability of this methods is given. We consider the two distinct cases：（i）τ≥ h, （ii）τ 〈 h, where the delay τ and step size h of the two-step continuity Runge-Kutta methods are both constant. The absolute stability regions of some methods are plotted and numerical examples show the efficiency of the method.

关键词： Analysis of numerical stability Singular delay differential equations Two-step continuity Runge-Kutta methods

Experimental investigations on characteristics of water-air two-phase flows during water-fillings in undulation pipelines

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Journal of Hydrodynamics 2024年第4期36卷 706-724页

作者： Xue-lin Tang Zong-ku liu ling Zhang xiao-qin li College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China Mingyang Smart Energy Group limited Zhongshan528400China

Visual and pressurized pipeline systems with single- and multi-undulation layouts were used to study experimentally and analyze theoretically the transient characteristics of water-air two-phase flow during water fillings in undulation pipelines based on the combination action analyses of both the communicating pipe and the gravity of the water-air two-phase flows in the descending pipe. For the single undulation pipeline, the complex two-phase flow-pattern evolutions including full pipe flow and stratified flow for low, medium, high water-filling velocity cases, respectively, lead to a great difference in transient pressure, flow pattern and the water-filling duration. Especially for low and medium water-filling velocity cases, the hydraulic theories related to hydraulic drop and hydraulic jump were employed to investigate the entrapped air pocket evolutions in the descending pipe, and the mechanism of negative pressure at the top of the undulation pipes was analyzed. For the same multi-undulation pipeline, due to the different elevations of the three undulation points along flow direction, namely three different types of pipeline layout, high-medium-low case (high elevation undulation point, medium one, and low one), low-medium-high and high-low-medium ones, their water-filling durations are significantly different, i.e., approximately 80.02 s, 227.34 s and 617.78 s. Meanwhile, there are significant differences in flow patterns in water filling, namely larger entrapped air pockets in three descending pipes for the high-medium-low case, entrapped air pockets in the first two descending pipes and open channel stratified flow in the last one for low-medium-high case, some bubbles in three descending pipes for the high-low-medium case.

关键词： Water-filling duration trapped air pockets water-air two-phase flow transient flow flow-pattern evolution multi-undulation pipelines

One-step Condensation/copolymerization of VTES and DVB for Self-assembly Bionic Superhydrophobic Surface Coating and Study on Oil-water Separation

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Journal of Bionic Engineering 2021年第3期18卷 559-573页

作者： Ruilong Zhang Zhiping Zhou yi Wang xiaohui Dai li Chen Jiangdong Dai Research School of Polymeric Materials School of Materials Science and EngineeringJiangsu UniversityZhenjiang 2120133China State Key Laboratory of NBC Protection for Civilian Beijing 102205China Institute of Green Chemistry and Chemical Technology Advanced Chemical Engineering Laboratory of Green Materials and Energy of Jiangsu ProvinceSchool of Chemistry and Chemical EngineeringJiangsu UniversityZhenjiang 212013China

Mimicry of nature drives the development of bionic *** superhydrophobic materials are a kind of high-efficiency materials to handle oil spills and water ***,the stability of surface coatings of the superhydrophobic materials remains a ***,a new category of self-assembly bionic superhydrophobic surface coating was prepared via one-step condensation/copolymerization of vinyltriethoxysilane(VTES)and divinylbenzene(DVB),which realized the close combination of covalent bonds between organic(***)and inorganic matter(***),and avoided the swelling of polydivinylbenzene(PDVB)in the process of collection of oil from *** organic-inorganic hybrid polymer could self-assembly deposit on the surface of sponge even other *** example,P(VTES-DVB)-Si0_(2)/MS obtained by assembling P(VTES-DVB)-Si0_(2)on the surface of Melamine Sponge(MS)exhibited superhydrophobicity with a Water Contact Angle(WCA)of 157.3,the optimal adsorption capacity of 77 g g 136 g g-1 for diverse oils,and an excellent separation efficiency of 99.3%.Besides,the excellent acid and alkali resistance of P(VTES-DVB)-Si0_(2)/MS suggested the potential value in practical oil-water separation.P(VTES-DVB)-Si0_(2)showed the outstanding hydrophobic performance by using as coating on different *** work provided a new idea about the stable combination of organic and inorganic matter in the surface modification.

关键词： superhydrophobic surface coating oil-water separation condensation copolymerization self-assembly organic-inorganic hybridism