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Particuology 2024年第7期90卷 404-411页

作者： Hanqiao Che Yuanhe Yue Zhaohua Jiang duan li School of Mechanical Engineering Guangxi UniversityNanningGuangxi530004China School of Chemical Engineering University of BirminghamBirminghamB152TTUK Hebei Engineering Research Center of Advanced Energy Storage Technology and Equipment School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China Hebei Key laboratory of Thermal Science and Energy Clean Utilization School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China School of Mechatronics and Vehicle Engineering Chongqing Jiaotong UniversityChongqing400074China School of Instrumentation and Opto-Electronic Engineering Beihang UniversityBeijing 100191China

The transient heat transfer behaviours in a packed bed have been studied using coupled computational fluid dynamics(CFD)and discrete element method(DEM).Intra-particle thermal diffusion,which is a crucial but rarely explored issue,is considered by introducing a one-dimensional diffusion equation in the DEM *** achieve a sufficiently long physical time of simulations,we further reduce the computational cost by applying periodic boundary condition to a small segment of the packed *** study demonstrates a shifting peak heat flow rate from the bottom to the top of the packed bed during the initial warming *** affirm that the influence of thermal diffusion within a particle is noteworthy only for particles exhibiting a high Biot number(e.g.,Bi=1.2).This insight enriches our understanding of heat transfer mechanisms in packed beds and their practical engineering applications.

关键词： Packed bed Intra-particle heat transfer CFD–DEM

New‑Generation Ferroelectric AlScN Materials

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Nano-Micro letters 2024年第11期16卷 88-118页

作者： Yalong Zhang Qiuxiang Zhu Bobo Tian Chungang duan Key laboratory of Polar Materials and Devices Ministry of EducationShanghai Center of Brain‑Inspired Intelligent Materials and DevicesDepartment of ElectronicsEast China Normal UniversityShanghai 200241People’s Republic of China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006ShanxiPeople’s Republic of China

Ferroelectrics have great potential in the field of nonvolatile memory due to programmable polarization states by external electric field in nonvolatile ***,complementary metal oxide semiconductor compatibility and uniformity of ferroelectric performance after size scaling have always been two thorny issues hindering practical application of ferroelectric memory *** emerging ferroelectricity of wurtzite structure nitride offers opportunities to circumvent the *** review covers the mechanism of ferroelectricity and domain dynamics in ferroelectric AlScN *** performance optimization of AlScN films grown by different techniques is summarized and their applications for memories and emerging in-memory computing are ***,the challenges and perspectives regarding the commercial avenue of ferroelectric AlScN are discussed.

关键词： AlScN Ferroelectrics Nonvolatile memory In-memory computing

Are Solar Active Regions Born with Neutralized Currents?

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Research in Astronomy and Astrophysics 2024年第7期24卷 79-88页

作者： Aiying duan Yaoyu xing Chaowei Jiang Planetary Environmental and Astrobiological Research laboratory(PEARl) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519000China Yunnan Key laboratory of the Solar Physics and Space Science Kunming 650216China Key laboratory of Tropical Atmosphere-Ocean System Sun Yat-sen UniversityMinistry of EducationZhuhai 519000China Institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518055China

Solar active regions(ARs)are formed by the emergence of current-carrying magnetic flux tubes from below the *** for an isolated flux tube the direct and return currents flowing along the tube should balance with each other,it remains controversial whether such a neutralization of currents is also maintained during the emergence *** we present a systematic survey of the degrees of the current neutralization in a large sample of flux-emerging ARs which appeared on the solar disk around the central meridian from 2010 to *** vector magnetograms taken by Helioseismic and Magnetic Imager onboard Solar Dynamic Observatory are employed to calculate the distributions of the vertical current density at the *** on the main phase of flux emergence,i.e.,the phase in which the total unsigned magnetic flux is continuously increased,we statistically examined the ratios of direct to return currents in all the *** a large-sample statistical study suggests that most of the ARs were born with currents close to *** degree of current neutralization seems to be not affected by the active-region size,the active-region growing rate,and the total unsigned *** only correlation of significance as found is that the stronger the magnetic field nonpotentiality is,the further the AR deviates from current neutrality,which supports previous event studies that eruption-productive ARs often have non-neutralized currents.

关键词： Sun magnetic fields-Sun flares-Sun corona-Sun coronal mass ejections(CMEs)

UAV swarm air combat maneuver decision-making method based on multi-agent reinforcement learning and transferring

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Science China(Information Sciences) 2024年第8期67卷 49-66页

作者： Zhiqiang ZHENG Chen WEI Haibin duan State Key laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical Engineering Beihang University

During short-range air combat involving unmanned aircraft vehicle(UAV) swarms, UAVs must make accurate maneuver decisions based on information from both enemy and friendly UAVs. This dual requirement of competition and cooperation presents a significant challenge in the field of unmanned air combat. In this paper, a method based on multi-agent reinforcement learning(MARl) is proposed to address this issue. An actor network containing three subnetworks that can handle different types of situational information is designed. Hence, the results from simpler one-on-one scenarios are leveraged to enhance the complex swarm air combat training process. Separate state spaces for local and global information are designed for the actor and critic networks. A detailed reward function is proposed to encourage *** prevent lazy participants in air combat, a reward assignment operation is applied to distribute these dense rewards. Simulation testing and ablation experiments demonstrate that both the transfer operation and reward assignment operation can effectively deal with the swarm air combat scenario, and reflect the effectiveness of the proposed method.

关键词： UAV swarm short-range air combat multi-agent reinforcement learning reward assignment transfer

Design, modeling, and evaluation of parallel continuum robots: A survey

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Science China(Technological Sciences) 2024年第3期67卷 673-695页

作者： CHEN Genliang TANG ShuJie duan xuYang WANG Hao Meta Robotics Institute Shanghai Jiao Tong UniversityShanghai 200240China State Key laboratory of Mechanical Systems and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key laboratory of Digital Manufacturing for Thin-Walled Structures Shanghai Jiao Tong UniversityShanghai 200240China

Parallel continuum robots(PCRs) have attracted increasing attention in the robotics community due to their simplicity in structure,inherence with compliance, and easiness of realization. Over the past decade, a variety of novel designs have been reported to enrich their diversity. However, there is a lack of systematic review of these emerging robots. To this end, this paper conducts a comprehensive survey on the mechanism design, kinetostatic modeling and analysis, and performance evaluation. For these robots, kinetostatic modeling plays a fundamental role throughout the design, analysis, and control stages. A systematic review of the existing approaches for kinetostatic modeling and analysis is provided, and a comparison is made to distinguish their differences. As well, a classification is made according to the characteristics of structure and actuation. In addition, performance evaluation on the workspace, stability, and singularity is also overviewed. Finally, the scenarios of potential applications are elaborated, and future research prospects are discussed. We believe that the information provided in this paper will be particularly useful for those who are interested in PCRs.

关键词： parallel continuum robots classification kinetostatic modeling performance evaluation

Prescribed-time leader-following consensus of linear multi-agent systems by bounded linear time-varying protocols

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Science China(Information Sciences) 2024年第1期67卷 140-153页

作者： Kai ZHANG Bin ZHOU xuefei YANG Guangren duan Center for Control Theory and Guidance Technology Harbin Institute of Technology

This paper considers the prescribed-time leader-following consensus problem of input-constrained linear multi-agent systems under generally directed communication topology in two cases:the laplacian matrix related to the entire communication topology between agents is either known or *** particular,the consensus problem for the former case is solved by a novel bounded linear time-varying(lTV) protocol,where the feedback gain is formulated by the parametric lyapunov equation and the knowledge of the laplacian ***,by utilizing a distributed observer,a fully bounded lTV protocol is proposed for the latter *** should be noted that,compared with the existing results,the system under consideration is more general,the designed protocols are linear,and the consensus problem is accomplished even in a fully distributed ***,the effectiveness of the proposed approach is verified by a numerical example.

关键词： leader-following consensus time-vary feedback prescribed-time control fully distributed consensus

Two-Dimensional Graphitic Carbon-Nitride(g-C_(3)N_(4))-Coated liNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)Cathodes for High-Energy-Density and long-life lithium Batteries

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Energy & Environmental Materials 2024年第6期7卷 140-149页

作者： Zhenliang duan Pengbo Zhai Ning Zhao xiangxin Guo College of Physics Qingdao UniversityQingdao 266071China College of Materials Science and Engineering Qingdao UniversityQingdao 266071China Tianmushan laboratory Xixi Octagon CityHangzhou 310023China

High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium ***,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle ***,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the liNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis *** an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal ***,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 *** a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:llZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.

关键词： cathode materials g-C_(3)N_(4)coating liNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) lithium batteries PVDF:llZTO electrolyte membranes

Study on site selection planning of urban electric vehicle charging station

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High Technology letters 2024年第1期30卷 75-84页

作者：刘娜 CHENG Jiaxin duan Yukai School of Business Shanghai Dianji UniversityShanghai201306 P.R.China

The large-scale development of electric vehicles(EVs)requires numerous charging stations to serve them,and the charging stations should be reasonably laid out and planned according to the charging demand of electric *** the costs of both operators and users,a site selection model for optimal layout planning of charging stations is constructed,and a queuing theory approach is used to determine the charging pile configuration to meet the charging demand in the planning *** solve the difficulties of particle swarm global optimization search,the improved random drift particle swarm optimization(IRDPSO)and Voronoi diagram are used to jointly solve for the optimal layout of electric *** final arithmetic analysis verifies the feasibility and practicality of the model and algorithm,and the results show that the total social cost is minimized when the charging station is 9,the location of the charging station is close to the center of gravity and the layout is reasonable.

关键词： charging station electric vehicle(EV) improved random drift particle swarm optimization(IRDPSO) optimal planning

Few-shot image recognition based on multi-scale features prototypical network

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High Technology letters 2024年第3期30卷 280-289页

作者： lIU Jiatong duan Yong School of Information Science Engineering Shenyang University of TechnologyShenyang 110870P.R.China Shenyang Key laboratory of Advanced Computing and Application Innovation Shenyang 110870P.R.China

In order to improve the model􀆳s capability in expressing features during few-shot learning,a multi-scale features prototypical network(MS-PN)algorithm is *** metric learning algo-rithm is employed to extract image features and project them into a feature space,thus evaluating the similarity between samples based on their relative distances within the metric *** sufficiently extract feature information from limited sample data and mitigate the impact of constrained data vol-ume,a multi-scale feature extraction network is presented to capture data features at various scales during the process of image feature ***,the position of the prototype is fine-tuned by assigning weights to data points to mitigate the influence of outliers on the *** loss function integrates contrastive loss and label-smoothing to bring similar data points closer and separate dissimilar data points within the metric *** evaluations are conducted on small-sample datasets mini-ImageNet and *** method in this paper can achieve higher classification ***,in the 5-way 1-shot experiment,classification accuracy reaches 50.13%and 66.79%respectively on these two ***,in the 5-way 5-shot ex-periment,accuracy of 66.79%and 85.91%are observed,respectively.

关键词： few-shot learning multi-scale feature prototypical network channel attention label-smoothing

KeyEE:Enhancing low-Resource Generative Event Extraction with Auxiliary Keyword Sub-Prompt

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Big Data Mining and Analytics 2024年第2期7卷 547-560页

作者： Junwen duan xincheng liao Ying An Jianxin Wang Hunan Key laboratory of Bioinformatics School of Computer Science and EngineeringCentral South UniversityChangsha 410083China Big Data Institute Central South UniversityChangsha 410083China

Event Extraction(EE)is a key task in information extraction,which requires high-quality annotated data that are often costly to *** classification-based methods suffer from low-resource scenarios due to the lack of label semantics and fine-grained *** recent approaches have endeavored to address EE through a more data-efficient generative process,they often overlook event keywords,which are vital for *** tackle these challenges,we introduce KeyEE,a multi-prompt learning strategy that improves low-resource event extraction by Event Keywords Extraction(EKE).We suggest employing an auxiliary EKE sub-prompt and concurrently training both EE and EKE with a shared pre-trained language *** the auxiliary sub-prompt,KeyEE learns event keywords knowledge implicitly,thereby reducing the dependence on annotated ***,we investigate and analyze various EKE sub-prompt strategies to encourage further research in this *** experiments on benchmark datasets ACE2005 and ERE show that KeyEE achieves significant improvement in low-resource settings and sets new state-of-the-art results.

关键词： natural language processing Event Extraction(EE) Multi-Prompt learning(MPl) low-resource