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A path planning algorithm for a crop monitoring fixed-wing unmanned aerial system

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science China(Information sciences) 2024年第08期67卷 5-23页

作者： Longhao QIAN Yi Lok LO hugh Hong-tao LIU Institute of Aerospace studies University of Toronto Department of Mechanical Engineering The University of Hong Kong

With the growing demand for automation in agriculture, industries increasingly rely on drones to perform crop monitoring and surveillance. In this regard, fixed-wing unmanned aerial systems(UAss)are viable platforms for scanning a large crop field, given their payload capacity and range. To achieve maximum coverage without landing for battery replacement, an algorithm for producing a minimal required energy survey path is essential. hence, an energy-aware coverage path planning algorithm is proposed *** constraints for a fixed-wing UAs to fly at low altitudes while achieving full coverage of the crop field are first analyzed. Then, the full path is decomposed into straight-line and U-turn primitives. Finally, an algorithm to calculate a combination of straight-line segments and U-turns is proposed to obtain the path with minimum required energy consumption. The genetic algorithm is used to efficiently determine the order of the straight-line paths to traverse. Case studies show that the proposed algorithm can produce planning results for a convex-polygon-shaped crop field.

关键词： path planning genetic algorithm energy minimization fixed-wing UAs aerial survey

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Carbon allocation in Picea jezoensis:Adaptation strategies of a non-treeline species at its upper elevation limit

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Forest Ecosystems 2024年第3期11卷 347-357页

作者： Renkai Dong Na Li Mai-he Li Yu Cong Haibo Du Decai Gao Hong s.he Key Laboratory of Geographical Processes and Ecological security in Changbai Mountains Ministry of EducationSchool of Geographical SciencesNortheast Normal UniversityChangchun130024China school of Natural Resources University of MissouriColumbiaMO65211USA swiss Federal Institute for Forest Snow and Landscape Research WSL8903BirmensdorfSwitzerland Northeast Institute of Geography and Agricultural Ecology Chinese Academy of SciencesChangchun130102China school of Life science Hebei UniversityBaoding071002China

Understanding the physiological adaptations of non-treeline trees to environmental stress is important to understand future shifts in species composition and distribution of current treeline *** aim of the present study was to elucidate the mechanisms of the formation of the upper elevation limit of non-treeline tree species,Picea jezoensis,and the carbon allocation strategies of the species on Changbai *** employed the^(13)C in situ pulse labeling technique to trace the distribution of photosynthetically assimilated carbon in Picea jezoensis at different elevational positions(tree species at its upper elevation limit(TsAUE,1,700 m a.s.l.)under treeline ecotone;tree species at a lower elevation position(TsALE,1,400 m a.s.l.).We analyzed^(13)C and the non-structural carbohydrate(NsC)concentrations in various tissues following *** findings revealed a significant shift in carbon allocation in TsAUE compared to *** was a pronounced increase inδ^(13)C allocation to belowground components(roots,soil,soil respiration)in TsAUE compared to ***,the C flow rate within the plant-soil-atmosphere system was faster,and the C residence time in the plant was shorter in *** trends indicate enhanced C sink activity in belowground tissues in TsAUE,with newly assimilated C being preferentially directed there,suggesting a more conservative C allocation strategy by *** at higher elevations under harsher *** a strategy,prioritizing C storage in roots,likely aids in withstanding winter cold stress at the expense of aboveground growth during the growing season,leading to reduced growth of TsAUE compared to *** results of the present study shed light on the adaptive mechanisms governing the upper elevation limits of non-treeline trees,and enhances our understanding of how non-treeline species might respond to ongoing climate change.

关键词： ^(13)C pulse labeling Carbon distribution Non-structural carbohydrates(NsC) Non-treeline species sink activity stressful environments Upper elevation limit

Honeycomb-like biochar framework coupled with Fe_(3)O_(4)/Fes nanoparticles as efficient heterogeneous Fenton catalyst for phenol degradation

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Journal of Environmental sciences 2024年第2期136卷 390-399页

作者： Aihua Cheng Yi he Xiaohe Liu Chi he Department of Environmental Engineering College of Geology and EnvironmentXi’an University of Science and TechnologyXi’an 710054China state Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China National Engineering Laboratory for VOCs Pollution Control Material and Technology University of Chinese Academy of SciencesBeijing 101408China

Achieving an efficient and stable heterogeneous Fenton reaction over a wide pH range is of great significance for wastewater ***,a pollen-derived biochar catalyst with a unique honeycomb-like structure,coupled with the dispersion of magnetic Fe_(3)O_(4)/Fes(Fe/s)nanoparticles,was synthesized by simple impregnation precursor,followed by *** prepared Fe/s-biochar catalyst demonstrated outstanding phenol degradation efficiency across a wide pH range,with 98%of which eliminated even under neutral conditions(pH 7.0).The high catalytic activity was due to the multilevel porous structure of pollenderived biochar provided enough active sites and allowed for better electron transfer,then increases oxidation ability to promote the ***,the acid microenvironment formed by sO_(4)^(2-)group from Fe/s composite extended the pH range for Fenton reaction,and s^(2-)facilitated the conversion of≡Fe^(3+)to≡Fe^(2+),resulting in remarkable degradation ***,biochar can effectively promote cycling stability by limiting Fe *** work may provide a general strategy for designing 3D framework biochar-based Fe/s catalysts with excellent performance for heterogeneous Fenton reactions.

关键词： Biomass Biochar Fenton reaction Fe_(3)O_(4)/Fes(Fe/s) Phenol degradation

H-and J-aggregation of conjugated small molecules in organic solar cells

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Journal of Energy Chemistry 2024年第6期93卷 174-192,I0005页

作者： Qiaoqiao Zhao Feng he state Key Laboratory of Biobased Material and Green Papermaking Qilu University of TechnologyShandong Academy of SciencesJinan 250353ShangdongChina shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and TechnologyShenzhen 518055GuangdongChina Guangdong Provincial Key Laboratory of Catalysis Southern University of Science and TechnologyShenzhen 518055GuangdongChina

As H-and J-aggregation receive more and more attention in the research of organic solar cells(OsCs),especially in small molecular systems,deep understanding of aggregation behavior is needed to guide the design of conjugated small molecular structure and the fabrication process of OsC *** this end,this review is ***,the review firstly introduced the basic information about H-and J-aggregation of conjugated small molecules in ***,the characteristics of H-and J-aggregation and the methods to identify them were ***,it reviewed the research progress of H-and J-aggregation of conjugated small molecules in OsCs,including the factors influencing H-and J-aggregation in thin film and the effects of H-and J-aggregation on OPV performance.

关键词： H-aggregation J-aggregation Organic solar cells small molecules Efficiency stability

A theory for three-dimensional response of micropolar plates

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1403-1414页

作者： Dianwu HUANG Linghui he College of Civil Engineering and Architectural Jiaxing UniversityJiaxing 314001Zhejiang ProvinceChina Department of Modern Mechanics and state Key Laboratory of Fire science University of Science and Technology of ChinaHefei 230026China

Through combined applications of the transfer-matrix method and asymptotic expansion technique,we formulate a theory to predict the three-dimensional response of micropolar *** ad hoc assumptions regarding through-thickness assumptions of the field variables are made,and the governing equations are two-dimensional,with the displacements and microrotations of the mid-plane as the *** the deformation of the mid-plane is solved,a three-dimensional micropolar elastic field within the plate is generated,which is exact up to the second order except in the boundary region close to the plate *** an illustrative example,the bending of a clamped infinitely long plate caused by a uniformly distributed transverse force is analyzed and discussed in detail.

关键词： micropolar plate transfer-matrix asymptotic expansion three-dimensional response

Distributed Optimal Variational GNE seeking in Merely Monotone Games

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IEEE/CAA Journal of Automatica sinica 2024年第7期11卷 1621-1630页

作者： Wangli he Yanzhen Wang IEEE the Key Laboratory of smart Manufacturing in Energy Chemical Process Ministry of EducationEast China University of Science and TechnologyShanghai 200237China

In this paper, the optimal variational generalized Nash equilibrium(v-GNE) seeking problem in merely monotone games with linearly coupled cost functions is investigated, in which the feasible strategy domain of each agent is coupled through an affine constraint. A distributed algorithm based on the hybrid steepest descent method is first proposed to seek the optimal v-GNE. Then, an accelerated algorithm with relaxation is proposed and analyzed, which has the potential to further improve the convergence speed to the optimal v-GNE. some sufficient conditions in both algorithms are obtained to ensure the global convergence towards the optimal v-GNE. To illustrate the performance of the algorithms, numerical simulation is conducted based on a networked Nash-Cournot game with bounded market capacities.

关键词： Distributed algorithms equilibria selection generalized Nash equilibrium(GNE) merely monotone games

Distributed Nash Equilibrium seeking on Compact Action sets over Jointly strongly Connected switching Networks

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Journal of systems science & Complexity 2024年第1期37卷 63-81页

作者： he Xiongnan HUANG Jie Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong Kong 999077China.

This paper studies the distributed Nash equilibrium seeking(DNEs)problem for games whose action sets are compact and whose network graph is switching satisfying the jointly strongly connected *** keep the actions of all players in their action sets all the time,one has to resort to the projected gradient-based *** the assumption that the unique Nash equilibrium is the unique equilibrium of the pseudogradient system,an algorithm is proposed that is able to exponentially find the Nash ***,the authors also consider the distributed Nash equilibrium seeking problem for games whose actions are governed by high-order integrator dynamics and belong to some compact *** examples are used to illustrate the proposed approach.

关键词： Compact action sets jointly strongly connected switching graphs Nash equilibrium seeking projected gradient-based algorithm.

High-Order Two-scale Asymptotic Paradigm for the Elastodynamic Homogenization of Periodic Composites

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Acta Mechanica solida sinica 2024年第1期37卷 124-138页

作者： Wei-Zhi Luo Mu he Liang Xia Qi-Chang he state Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Laboratoire Modélisation et simulation Multi-Echelle MSME UMR 8208 CNRSUniversite Gustave Eiffel77454 Marne-la-ValléeFrance

The classical two-scale asymptotic paradigm provides macroscopic and microscopic analyses for the elastodynamic homogenization of periodic composites based on the spatial or/and temporal variable,which offers an approximate framework for the asymptotic homogenization analysis of the motion ***,in this framework,the growing complexity of the homogenization formulation gradually becomes an obstacle as the asymptotic order *** such a context,a compact,fast,and accurate asymptotic paradigm is *** work reviews the high-order spatial two-scale asymptotic paradigm with the effective displacement field representation and optimizes the implementation by symmetrizing the tensor to be ***,the modified implementation gets rid of the excessive memory consumption required for computing the high-order tensor,which is demonstrated by representative one-and two-dimensional *** numerical results show that(1)the contrast of the material parameters between media in composites directly affects the convergence rate of the asymptotic results for the homogenization of periodic composites,(2)the convergence error of the asymptotic results mainly comes from the truncation error of the modified asymptotic homogenized motion equation,and(3)the excessive norm of the normalized wavenumber vector in the two-dimensional inclusion case may lead to a non-convergence of the asymptotic results.

关键词： Composites Homogenization Asymptotic analysis Dynamics Dispersion

Coupled Numerical simulation of Electromagnetic and Flow Fields in a Magnetohydrodynamic Induction Pump

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Fluid Dynamics & Materials Processing 2024年第4期20卷 889-899页

作者： he Wang Ying he College of Transportation Ludong UniversityYantai264025China College of Intelligent Manufacturing City College of HuizhouHuizhou516025China

Magnetohydrodynamic(MHD)induction pumps are contactless pumps able to withstand harsh *** rate of fluid flow through the pump directly affects the efficiency and stability of the *** explore the influence of induction pump settings on the related delivery speed,in this study,a numerical model for coupled electromagnetic and flow field effects is introduced and used to simulate liquid metal lithium flow in the induction *** effects of current intensity,frequency,coil turns and coil winding size on the velocity of the working fluid are *** is shown that the first three parameters have a significant impact,while changes in the coil turns have a negligible *** maximum increase in working fluid velocity within the pump for the parameter combination investigated in this paper is approximately 618%.As the frequency is increased from 20 to 60 Hz,the maximum increase in the mean flow rate of the working fluid is approximately 241%.These research findings are intended to support the design and optimization of these devices.

关键词： Magnetic fluid multi-physical field coupling induction pump numerical simulation liquid metal conveying