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3D-shaped 3D-continuously graphene cellulose(3D^(2)GC)architecture

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Nano Research 2024年第7期17卷 6695-6699页

作者： Abdelrahman Brakat Hongwei Zhu State key lab.of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

In the endeavor to develop three-dimensional(3D)-architected sophisticated hierarchical structures,the synergy between inplane and out-of-plane interactions at interfaces offers new *** interplay,governed by van der Waals(vdW)interfacial nanoarchitectonics,facilitates the design of efficient thermally conductive *** work delves into the kinetics underlying a dual-templating strategy,seamlessly integrating two-dimensional(2D)-graphene sheets with one-dimensional(1D)-cellulose chains at heterointerfaces,thereby transforming into 3D-shaped and 3D-continuously anisotropic structures,termed as(3D^(2)GC)***,we designed and fabricated an anisotropic graphene cellulose scaffold(GCS)employing a nickel *** as-grown GCS replicates the 3D-shaped and configuration of the *** 3D-continuously interconnected fibrous-porous network of the GCS,combined with its anisotropic thermal properties(λ_(axial)/λ_(radial)),not only is promising for advanced thermal technologies but also offers advantages in cost-effectiveness and eco-effectiveness.

关键词： two-dimensional(2D)-graphene one-dimensional(1D)-cellulose heterointerface anisotropic three-dimensional(3D)-architecture

key points and visible part fusion attention network for occluded pedestrian detection in traffic environments

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Optoelectronics Letters 2024年第7期20卷 430-436页

作者： LIU Peiyu MA Yixuan School of software engineering Beijing Jiaotong UniversityBeijing 100044China

Aiming at the problem of low detection accuracy of occluded pedestrian in traffic environments,this paper proposes a key points and visible part fusion network for occluded pedestrian *** proposed algorithm constructs two attention modules by introducing human key points and the bounding box of visible parts respectively,which suppresses the occluded parts in the channel features and spatial features of pedestrian features *** results on CityPersons and Caltech datasets demonstrate the effectiveness of the proposed *** missing rate(MR)is reduced to 40.78 on the Heavy subset of the CityPersons dataset and surpasses many outstanding methods.

关键词： methods. network visible

Heterointerface engineering of assembled CoP_(2) on N-modified carbon as efficient trifunctional electrocatalysts for Zn-Air batteries and overall water splitting

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Nano Research 2024年第5期17卷 3801-3809页

作者： Yan Chen Zhenrui Yang Juan Wang Yun Yang Xuedong He Yang Wang Jiadong Chen Yaqing Guo Xin Wang Shun Wang Huile Jin Wenzhou key lab.of Advanced Energy Storage and Conversion Zhejiang Province Key Lab of Leather EngineeringCollege of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China Zhejiang engineering Research Center for Electrochemical Energy Materials and Devices Institute of New Materials and Industrial TechnologiesWenzhou UniversityWenzhou 325035China School of Chemical and Biomedical engineering Nanyang Technological UniversitySingapore 637459Singapore

Enhancing catalytic activity through modulating the interaction between N-doped carbon and metal phosphides clusters is an effective ***,the electronic structure modulation of CoP_(2) supported N-modified carbon(CoP_(2)/NC)has been designed and prepared as efficient electrocatalysts for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER).Notably,CoP_(2)/NC-1 catalyst exhibits impressive performance in alkaline media,with an ORR half-wave potential of 0.84 V,as well as OER and HER overpotentials of 290 and 129 mV(at 10 mA·cm^(−2)),*** addition,CoP_(2)/NC-1 produces a power density as high as 172.9 mW·cm^(−2),and excellent reversibility of 100 h at 20 mA·cm^(−2) in home-made Zn-air *** experimental results demonstrate that the synergistic interactions between N modified carbon substrate and CoP_(2) material significantly enhance the kinetics of ORR,OER,and *** functional theory(DFT)calculations reveal the strong electrons redistribution of CoP_(2) induced by high-density N atoms at the interface,thus optimizing the key intermediates and significantly lower the energy barrier of *** electronic adjustments of CoP_(2) greatly enhance its kinetics of ORR/OER/HER,leading to faster *** study provides profound insights into the specific modification of CoP_(2) by N-doped carbon,enabling the construction of efficient catalysts.

关键词： two-dimensional(2D)carbon metal-organic framework cobalt phosphide zinc air battery water splitting

Study on Catalytic Behavior of Iron-based Catalyst with IITP as Electron Donor in the Polymerization of Butadiene

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Chinese Journal of Polymer Science 2024年第5期42卷 612-619,I0007页

作者： Shi-Liang Xu Ying-Nan Zhao Yao Yu Qi Yang Li-Hua Na Heng Liu Chun-Yu Zhang Xue-Quan Zhang key lab.ratory of Advanced Rubber Material Ministry of EducationSchool of Polymer Science and EngineeringQingdao University of Science&TechnologyQingdao266042China Shandong Provincial College lab.ratory of Rubber Material and engineering School of Polymer Science and EngineeringQingdao University of Science&TechnologyQingdao266042China key lab.of Rubber-Plastics Ministry of Education/Shandong Provincial Key Lab of Rubber-plasticsSchool of Polymer Science and EngineeringQingdao University of Science&TechnologyQingdao266042China

In this study,a novel iron-based catalyst system,Fe(acac)3/(isocyanoimino)triptenylphosphorane(IITP)/AlR3,was employed for the synthesis of syndiotactic 1,2-polybutadiene in *** catalyst system exhibits remarkably high catalytic activity,achieving a polymerization activity of 762 kgpolymer·molcatalyst^(-1)·h^(-1)at 50℃with a[BD]/[Fe]molar ratio of ***,living polymerization characteristic were observed during the investigation of the polymerization kinetics of 1,3-butadiene *** characteristics were well demonstrated by a narrow molecular weight distribution(PDI≈2.0)of the resulting polybutadiene and a linear relationship between-ln(1-c)and polymerization time as well as number average molecular weight and polymer *** resultant polymer showed a 1,2-selectivity of approximately 76%and stereoregularity ranging from 62%to 73%(rrrr).Additionally,through kinetic studies on polymerization reaction,an apparent activation energy Ea value of this catalytic system was calculated to be 84.98 kJ·mol^(-1),which suggests that high polymerization temperature favors efficient polymerization.

关键词： Iron catalyst Syndiotactic 1,2-polybutadiene Elastomers Donor Selectivity

Multi-user reinforcement learning based task migration in mobile edge computing

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Frontiers of Computer Science 2024年第4期18卷 161-173页

作者： Yuya CUI Degan ZHANG Jie ZHANG Ting ZHANG Lixiang CAO Lu CHEN Tianjin key lab.of Intelligent Computing and Novel software Technology Tianjin University of TechnologyTianjin 300384China School of Internet of Things engineering Jiangsu Vocational College of Information TechnologyWuxi 214153China School of Electronic and Information engineering Beijing Jiaotong UniversityBeijing 100044China School of Sports Economics and Management Tianjin University of SportTianjin 301617China

Mobile Edge Computing(MEC)is a promising *** service migration is a key technology in *** order to maintain the continuity of services in a dynamic environment,mobile users need to migrate tasks between multiple servers in real *** to the uncertainty of movement,frequent migration will increase delays and costs and non-migration will lead to service ***,it is very challenging to design an optimal migration *** this paper,we investigate the multi-user task migration problem in a dynamic environment and minimizes the average service delay while meeting the migration *** order to optimize the service delay and migration cost,we propose an adaptive weight deep deterministic policy gradient(AWDDPG)*** distributed execution and centralized training are adopted to solve the high-dimensional *** show that the proposed algorithm can greatly reduce the migration cost and service delay compared with the other related algorithms.

关键词： mobile edge computing mobility service migration deep reinforcement learning deep deterministic policy gradient

Harnessing overlapped temperature-salinity gradient in solar-driven interfacial seawater evaporation for efficient steam and electricity generation

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Journal of Energy Chemistry 2024年第8期95卷 694-700,I0015页

作者： Peida Li Dongtong He Jingchang Sun Jieshan Qiu Zhiyu Wang State key lab.of Fine Chemicals Liaoning Key Lab for Energy Materials and Chemical EngineeringDalian University of TechnologyDalian 116024LiaoningChina School of Physics and Electronic Technology Liaoning Normal UniversityDalian 116029LiaoningChina College of Chemical engineering Beijing University of Chemical TechnologyBeijing 100029China

Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater *** also engenders overlapped temperaturesalinity gradient(TSG)between water-air interface and adjacent seawater,affording opportunities of harnessing ***,the efficiency of conventional SIWE technologies is limited by significant challenges,including salt passivation to hinder evaporation and difficulties in exploiting overlapped TSG ***,we report self-sustaining hybrid SIWE for not only sustainable seawater desalination but also efficient electricity generation from *** enables spontaneous circulation of salt flux upon seawater evaporation,inducing a self-cleaning evaporative interface without salt passivation for stable steam ***,this design enables spatial separation and simultaneous utilization of overlapped TSG to enhance electricity *** benefits render a remarkable efficiency of90.8%in solar energy utilization,manifesting in co-generation of solar steam at a fast rate of 2.01 kg m^(-2)-h^(-1)and electricity power of 1.91 W m^(-2)with high *** interfacing the hybrid SIWE with seawater electrolyzer constructs a system for water-electricity-hydrogen co-generation without external electricity *** produces hydrogen at a rapid rate of 1.29 L h^(-1)m^(-2)and freshwater with 22 times lower Na+concentration than the World Health Organization(WHO)threshold.

关键词： Solar-driven interfacial water evaporation Steam generation Electricity generation Seawater

Enhanced Natural Convection for Accelerating Melting of Phase Change Material in Cellular Structure through Inserting Fin

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Journal of Thermal Science 2024年第2期33卷 548-563页

作者： KONG Dekui ZHANG Yongcun LIU Shutian State key lab.ratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian116024China

The design of thermal conductivity enhancers(TCE) is quite critical to overcoming the disadvantage of the poor thermal conductivity of phase change materials(PCM).The main contribution of this study is firstly to discuss how to actively enhance natural convection of the melted PCM in cellular structure by the fin formed in the structure under the condition of the same metal mass,apart from simultaneously improving heat conduction,which can boost the heat transfer ***,a tailored hybrid fin-lattice structure(HFS) as TCE is designed and fabricated by additive manufacturing(AM).A two-equation numerical method is applied to study the heat transfer of the PCM,and its feasibility is validated with the experimental *** numerical results indicate that enhanced natural convection and improved heat conduction can be obtained simultaneously when a well-designed fin is embedded into a lattice *** enhanced natural convection results in the improved melting rate and the decreased wall temperature;e.g.,the complete melting time and the wall temperature are reduced by 11.6% and 19.7%,respectively,because of the fin for metal ***,the parameters of HFS including the porosity,pore density,and fin dimension have a great impact on the heat *** enhancement effect of the fin for HFS on the melting rate of the PCM increases as the thermal conductivity of the base material *** example,when the fin is introduced into the lattice structure,the complete melting time is reduced by 24.1% for metal *** summary,this study enables us to obtain a good understanding of the mechanism of the heat transfer and provides necessary experimental data for the structural design of HFS fabricated by AM.

关键词： natural convection heat transfer enhancement phase change material additive manufacturing hybrid fin-lattice structure

Massively parallel algorithms for fully dynamic all-pairs shortest paths

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Frontiers of Computer Science 2024年第4期18卷 201-203页

作者： Chilei WANG Qiang-Sheng HUA Hai JIN Chaodong ZHENG National engineering Research Center for Big Data Technology and System Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China State key lab.ratory for Novel software Technology Nanjing UniversityNanjing 210023China

1 Introduction In recent years,the Massively Parallel Computation(MPC)model has gained significant ***,most of distributed and parallel graph algorithms in the MPC model are designed for static graphs[1].In fact,the graphs in the real world are constantly *** size of the real-time changes in these graphs is smaller and more *** graph algorithms[2,3]can deal with graph changes more efficiently[4]than the corresponding static graph ***,most studies on dynamic graph algorithms are limited to the single machine ***,a few parallel dynamic graph algorithms(such as the graph connectivity)in the MPC model[5]have been proposed and shown superiority over their parallel static counterparts.

关键词： dynamic shortest gained

Model gradient: unified model and policy learning in model-based reinforcement learning

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Frontiers of Computer Science 2024年第4期18卷 117-128页

作者： Chengxing JIA Fuxiang ZHANG Tian XU Jing-Cheng PANG Zongzhang ZHANG Yang YU National key lab.ratory for Novel software Technology Nanjing UniversityNanjing 210023China Polixir Technologies Nanjing 210000China

Model-based reinforcement learning is a promising direction to improve the sample efficiency of reinforcement learning with learning a model of the *** model learning methods aim at fitting the transition data,and commonly employ a supervised learning approach to minimize the distance between the predicted state and the real *** supervised model learning methods,however,diverge from the ultimate goal of model learning,i.e.,optimizing the learned-in-the-model *** this work,we investigate how model learning and policy learning can share the same objective of maximizing the expected return in the real *** find model learning towards this objective can result in a target of enhancing the similarity between the gradient on generated data and the gradient on the real *** thus derive the gradient of the model from this target and propose the Model Gradient algorithm(MG)to integrate this novel model learning approach with policy-gradient-based policy *** conduct experiments on multiple locomotion control tasks and find that MG can not only achieve high sample efficiency but also lead to better convergence performance compared to traditional model-based reinforcement learning approaches.

关键词： reinforcement learning model-based reinforcement learning Markov decision process