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Planar Graphs whose Second Largest Eigenvalue Smaller than ■

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Journal of Mathematical Research with Applications 2024年第1期44卷 1-6页

作者： Zihao geng Jiming GUO Department of Mathematics East China University of Science and Technology

A graph G is said to be planar if G can be drawn on the plane in such a way that its edges intersect only at their *** this paper,all the planar graphs without isolated vertices whose second largest eigenvalue smaller... 详细信息

关键词： planar graph the second largest eigenvalue complete product

AHLNet:Adaptive Multihead Structure and Lightweight Feature Pyramid Network for Detection of Live Working in Substations

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Machine Intelligence Research 2024年第5期21卷 983-992页

作者： Mengle Peng Xiaoyong Jiang Langyue Huang Zhongyi Li Haiteng Wu Xiaotang geng Zhejiang University of Science and Technology Hangzhou310023China Zhejiang Key Laboratory of Intelligent Operation and Maintenance Robot Hangzhou311100China

With the increasing demand for power in society,there is much live equipment in substations,and the safety and standardization of live working of workers are facing *** at these problems of scene complexity and object diversity in the real-time detection of the live working safety of substation workers,an adaptive multihead structure and lightweight feature pyramid-based network(AHLNet)is proposed in this study,which is based on ***,we take AH-Darknet53 as the backbone network of YOLOV3,which can introduce an adaptive multihead(AMH)structure,reduce the number of network parameters,and improve the feature extraction ability of the backbone ***,to reduce the number of convolution layers of the deeper feature map,a lightweight feature pyramid network(LFPN)is proposed,which can perform feature fusion in advance to alleviate the problem of feature imbalance and gradient ***,the proposed AHLNet is evaluated on the datasets of 1. categories of substation safety operation scenarios,and the average prediction accuracy MAP_(50)reaches 82.1.%.Compared with YOLOV3,MAP_(50)is increased by 2.43%,and the number of parameters is 90 M,which is only 38%of the number of parameters of *** addition,the detection speed is basically the same as that of YOLOV3,which can meet the real-time and accurate detection requirements for the safe operation of substation staff.

关键词： Adaptive multihead structure lightweight feature pyramid substation feature imbalance multiobject detection

Dynamic Organization of Large-scale Functional Brain Networks Supports Interactions Between Emotion and Executive Control

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Neuroscience Bulletin 2024年第7期40卷 981-991页

作者： Haiyang geng Pengfei Xu Andre Aleman Shaozheng Qin Yue-Jia Luo State Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal UniversityBeijing 100875China Tianqiao and Chrissy Chen Institute for Translational ResearchShanghai 200040China Beijing Key Laboratory of Applied Experimental Psychology National Demonstration Center for Experimental Psychology Education(BNU)Faculty of PsychologyBeijing Normal UniversityBeijing 100875China Center for Neuroimaging Shenzhen Institute of NeuroscienceShenzhen 518107China University of Groningen Department of Biomedical Sciences of Cells and SystemsSection Cognitive NeuroscienceUniversity Medical Center GroningenGroningenThe Netherlands Institute for Neuropsychological Rehabilitation University of Health and Rehabilitation SciencesQingdao 266113China Shenzhen Key Laboratory of Affective and Social Neuroscience Magnetic Resonance ImagingCenter for Brain Disorders and Cognitive SciencesShenzhen UniversityShenzhen 518060China Chinese Institute for Brain Research Beijing 102206China

Emotion and executive control are often conceptualized as two distinct modes of human brain ***,however,is known about how the dynamic organization of large-scale functional brain networks that support flexible emotion processing and executive control,especially their *** amygdala and prefrontal systems have long been thought to play crucial roles in these *** advances in human neuroimaging studies have begun to delineate functional organization principles among the large-scale brain networks underlying emotion,executive control,and their ***,we propose a dynamic brain network model to account for interactive competition between emotion and executive control by reviewing recent resting-state and task-related neuroimaging studies using network-based *** this model,dynamic interactions among the executive control network,the salience network,the default mode network,and sensorimotor networks enable dynamic processes of emotion and support flexible executive control of multiple processes;neural oscillations across multiple frequency bands and the locus coeruleus−norepinephrine pathway serve as communicational mechanisms underlying dynamic synergy among large-scale functional brain *** model has important implications for understanding how the dynamic organization of complex brain systems and networks empowers flexible cognitive and affective functions.

关键词： Dynamic brain network Emotion Executive control Salience network Executive control network Default mode network

Investigation on cavitating turbulent flow for the twisted NACA66 hydrofoil using a PANS model with helicity modification

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Journal of Hydrodynamics 2024年第2期36卷 219-231页

作者： Chen geng Zhao-hui Qian Ke-xin Zheng Wei-xiang Ye Xian-wu Luo State Key Laboratory of Hydroscience cand Engineering Deparment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China

In the present paper,the unsteady cavitating turbulent flow over the twisted NACA66 hydrofoil is investigated based on an modified shear stress transfer k-ωpartially averaged Navier-Stokes(MSST PANS)model,i.e.,new MSST PANS(NMSST PANS)model,where the production term of kinetic energy in the turbulence model is modified with *** with the experimental data,cavitation evolution and its characteristic frequency are satisfactorily predicted by the proposed NMSST PANS *** is revealed that the interaction among the main flow,the reentrant jets,and sheet cavitation causes the formation of the primary shedding cavity near the mid-span and the secondary shedding cavity at each side of the twisted hydrofoil,and further induces the remarkable pressure gradient around shedding *** with the development of the primary and the secondary shedding cavities,the great pressure gradient associated with large cavity volume variation promotes the vortical flow generation and the spatial deformation of vortex structure during cavitation evolution,and results in the primary and the secondary U-type ***,dynamic mode decomposition(DMD)analysis is utilized to confirm the interaction among the main flow,the main reentrant jet and two side reentrant jets,and *** results indicate that the proposed NMSST PANS model is suitable to simulate the complicated cavitating turbulent flow for various engineering applications.

关键词： Cavitating turbulent flow partially averaged Navier-Stokes(PANS)model hydrofoil numerical simulation

Deployment optimization for target perpetual coverage in energy harvesting wireless sensor network

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Digital Communications and Networks 2024年第2期10卷 498-508页

作者： Zhenkun Jin Yixuan geng Chenlu Zhu Yunzhi Xia Xianjun Deng Lingzhi Yi Xianlan Wang Wuhan Business University 430056China Wuhan Research Institute of Post and Telecommunication Wuhan430074China Hubei Key Laboratory of Distributed System Security Hubei Engineering Research Center on Big Data SecuritySchool of Cyber Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Hubei Chutian Expressway Digital Technology Co.Ltd Wuhan430074China School of Information and Safety Engineering Zhongnan University of Economics and LawWuhan430073China

Energy limitation of traditional Wireless Sensor Networks(WSNs)greatly confines the network lifetime due to generating and processing massive sensing data with a limited *** energy harvesting WSN is a novel network architecture to address the limitation of traditional ***,existing coverage and deployment schemes neglect the environmental correlation of sensor nodes and external energy with respect to physical *** considering the spatial correlation of the environment and the uneven distribution of energy in energy harvesting WSN,we investigate how to deploy a collection of sensor nodes to save the deployment cost while ensuring the target perpetual *** Confident Information Coverage(CIC)model is adopted to formulate the CIC Minimum Deployment Cost Target Perpetual Coverage(CICMTP)problem to minimize the deployed sensor *** the CICMTP is NP-hard,we devise two approximation algorithms named Local Greedy Threshold Algorithm based on CIC(LGTA-CIC)and Overall Greedy Search Algorithm based on CIC(OGSA-CIC).The LGTA-CIC has a low time complexity and the OGSA-CIC has a better approximation *** simulation results demonstrate that the OGSA-CIC is able to achieve lower deployment cost and the performance of the proposed algorithms outperforms GRNP,TPNP and EENP algorithms.

关键词： Energy harvesting WSN Deployment optimization Confident information coverage(CIC) Target perpetual coverage

Recent advances and future prospects on Ni_(3)S_(2)-Based electrocatalysts for efficient alkaline water electrolysis

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Green Energy & Environment 2024年第4期9卷 659-683页

作者： Shiwen Wang Zhen geng Songhu Bi Yuwei Wang Zijian Gao Liming Jin Cunman Zhang Clean Energy Automotive Engineering Center School of Automotive StudiesTongji UniversityShanghai201804China

Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon ***,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water ***_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal ***,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water ***,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are *** challenges and perspectives are also analyzed.

关键词： Alkaline water electrolysis Hydrogen Electrocatalysts Ni_(3)S_(2)

A frequency servo SoC with output power stabilization loop technology for miniaturized atomic clocks

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Journal of Semiconductors 2024年第6期45卷 13-22页

作者： Hongyang Zhang Xinlin geng Zonglin Ye Kailei Wang Qian Xie Zheng Wang School of Integrated Circuit Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic *** proposed power stabilization loop(PSL)technique,incorporating an off-chip power detector(PD),ensures that the output power of the FS-SoC remains stable,mitigating the impact of power fluctuations on the atomic clock's ***,a one-pulse-per-second(1.PS)is employed to syn-chronize the clock with *** using 65 nm CMOS technology,the measured phase noise of the FS-SoC stands at-69.5 dBc/Hz@1.0 Hz offset and-83.9 dBc/Hz@1.kHz offset,accompanied by a power dissipation of 1..7 *** Cs atomic clock employing the proposed FS-SoC and PSL obtains an Allan deviation of 1.7×1.^(-1.) with 1.s averaging time.

关键词： CMOS technology atomic clock phase-locked loop output power stabilization 1.PS

Spatiotemporal Evolution of Urban Heat Islands and Optimization of Spatial Network Construction in the Central Urban Area of Fuzhou City, China

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Chinese Geographical Science 2024年第5期34卷 917-930页

作者： ZHAO Qiuyue YU Kunyong geng Jianwei LIN Jiqing AI Jingwen LIU Jian College of Landscape Architecture Fujian Agriculture and Forestry UniversityFuzhou 350002China University Key Lab for Geomatics Technology and Optimize Resources Utilization in Fujian Province Fujian Agriculture and Forestry UniversityFuzhou 350002China

Although accelerated urbanization has led to economic prosperity,it has also resulted in urban heat island ***,identifying methods of using limited urban spaces to alleviate heat islands has become an urgent *** this study,we assessed the spatiotemporal evolution of urban heat islands within the central urban area of Fuzhou City,China from 201. to *** assessment was based on a morphological spatial pattern analysis(MSPA)model and an urban thermal environment spatial network constructed us-ing the minimum cumulative resistance(MCR)*** measures for the spatial network were proposed to provide a theor-etical basis for alleviating urban heat *** results show that the heat island area within the study area gradually increased while that of urban cold island area gradually *** core area was the largest of the urban heat island patch landscape elements with a significant impact on other landscape elements,and represented an important factor underlying urban heat island network *** thermal environment network revealed a total of 1.7 thermal environment corridors and 93 heat island *** locations were then optimized according to the current land use,which maximized the potential of 1.99.83 *** based on current land use led to an increase in climate resilience,with effective measures showing reduction in thermal environment spatial network structure and function,contributing to the mitigation of urban heat *** findings support the use of current land use patterns during urban heat island mitigation measure planning,thus providing an important reference basis for alleviating urban heat island effects.

关键词： urban heat island spatiotemporal analysis circuit theory post optimization evaluation climate mitigation Fuzhou City,China

Remarkable Wear Resistance in a Complex Concentrated Alloy with Nanohierarchical Architecture and Composition Undulation

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Research 2024年第1期2023卷 403-416页

作者： Yushan geng Wenyuan Chen Hui Tan Jun Cheng Shengyu Zhu Jun Yang Weimin Liu State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000PR China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049PR China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264000PR China

Sustained wear damages on the sliding surfaces of alloys are generally the culprit responsible for the failure of various mechanical *** by high-entropy effects,here we deliberately deploy nanohierarchical architecture with composition undulation in a Ni50(AlNbTiV)_(50) complex concentrated alloy,which yields ultralow wear rate within the order of 1.^(−7) to 1.^(−6) mm^(3)/Nm between room temperature and 800℃.Such remarkable wear resistance heretofore represents one of the highest wear resistance reported for the bulk alloys or composites,and originates from the multi-type adaptive friction interface protection governed by intrinsically nano-coupled grains and *** cooperative heterostructure releases gradient frictional stress in stages upon wear at room temperature through the coexistence of multiple deformation pathways while activating a dense nanocrystalline glaze layer upon wear at 800℃ to minimize adhesive and oxidative *** work uncovers a practical avenue for tailoring wear properties with multicomponent heterostructures over a wide temperature range.

关键词： wear alloys friction