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Method for the fruit tree recognition and navigation in complex environment of an agricultural robot

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International Journal of Agricultural and Biological Engineering 2024年第2期17卷 221-229页

作者： Xiaolin xie Yuchao Li Lijun Zhao Xin jin Shengsheng Wang Xiaobing han College of Agricultural Equipment Engineering Henan University of Science and TechnologyLuoyang 471003HenanChina Collaborative Innovation Center of Machinery Equipment Advanced Manufacturing of Henan Province Luoyang 471003HenanChina Longmen Laboratory Luoyang 471003HenanChina College of Intelligent and Manufacturing Engineering Chongqing University of Arts and SciencesChongqing 402160China

To realize the visual navigation of agricultural robots in the complex environment of orchards,this study proposed a method for fruit tree recognition and navigation based on *** YOLOv5s model was selected and trained to identify the trunks of the left and right rows of fruit trees;the quadratic curve was fitted to the bottom center of the fruit tree recognition box,and the identified fruit trees were divided into left and right columns by using the extreme value point of the quadratic curve to obtain the left and right rows of fruit trees;the straight-line equation of the left and right fruit tree rows was further solved,the median line of the two straight lines was taken as the expected navigation path of the robot,and the path tracing navigation experiment was carried out by using the improved LQR control *** experimental results show that under the guidance of the machine vision system and guided by the improved LQR control algorithm,the lateral error and heading error can converge quickly to the desired navigation path in the four initial states of[0 m,−0.34 rad],[0.10 m,0.34 rad],[0.15 m,0 rad]and[0.20 m,−0.34 rad].When the initial speed was 0.5 m/s,the average lateral error was 0.059 m and the average heading error was 0.2787 rad for the navigation trials in the four different initial *** average driving was 5.3 m into the steady state,the average value of steady state lateral error was 0.0102 m,the average value of steady state heading error was 0.0253 rad,and the average relative error of the robot driving along the desired navigation path was 4.6%.The results indicate that the navigation algorithm proposed in this study has good robustness,meets the operational requirements of robot autonomous navigation in orchard environment,and improves the reliability of robot driving in orchard.

关键词： fruit tree recognition visual navigation YOLOv5 complex environments orchards

Analytical model for the sealant performance of tunnel gasketed joints based on multi-scale contact and percolation theories

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Underground Space 2024年第1期14卷 319-337页

作者： Jiachong xie Xin Huang Guolong jin Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Geotechnical and Underground Engineering Ministry of EducationShanghai 200092China College of Civil Engineering&Architecture Xinjiang UniversityUrumqi 830047China China Shipbuilding NDRI Engineering Co. Ltd.Shanghai 200063China

The localised leakage in shield tunnels that mainly occurs at segment joints may induce other defects,which threatens operational *** obtain a universal solution for the sealant performance of gasketed joints,we proposed a novel analytical model based on the multiscale contact and percolation theories,in which the obtained percolation pressure and interfacial separation can be utilized to derive the critical water leakage pressure and leakage *** evolutionary process of leakage was divided into three stages(i.e.,the percolation,leakage and breakdown),which explicitly reveal the progressive hydraulic deterioration of gasketed *** gaskets still own partial waterproof capacity until the end of the leakage stage due to the remaining contact pressure at surface *** proposed model was first verified by several sets of experimental data,based on which the determination of three key model parameters(i.e.,self-sealing slope,sealing coefficient,and expel pressure)were discussed in *** parametric study indicates that the waterproof capacity is significantly affected by the joint opening,offset,and the surface roughness of the *** variation in waterproof capacity with joint opening is mainly due to the nonlinearity of the gasket’s modulus and self-sealing *** increase in joint offset can result in a lower waterproof capacity as well as a larger leakage ***’s surface roughness affects the percolation pressure and interfacial separation,which contributes to the long-term sealant performance.

关键词： Shield tunnel Gasketed joint Sealant performance Hydraulic deterioration Percolation theory Surface roughness Leakage rate

Evaluation and Projection of Population Exposure to Temperature Extremes over the Beijing−Tianjin−Hebei Region Using a High-Resolution Regional Climate Model RegCM4 Ensemble

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Advances in Atmospheric Sciences 2024年第6期41卷 1132-1146页

作者： Peihua QIN Zhenghui xie Rui han Buchun LIU State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences(CAAS)Beijing 100081China

Temperature extremes over rapidly urbanizing regions with high population densities have been scrutinized due to their severe impacts on human safety and *** of all,the performance of the regional climate model RegCM4 with a hydrostatic or non-hydrostatic dynamic core in simulating seasonal temperature and temperature extremes was evaluated over the historical period of 1991–99 at a 12-km spatial resolution over China and a 3-km resolution over the Beijing−Tianjin−Hebei(JJJ)region,a typical urban agglomeration of *** of spatial distributions of temperature extremes over the JJJ region using RegCM4 with hydrostatic and non-hydrostatic cores showed high spatial correlations of more than 0.8 with the *** a warming climate,temperature extremes of annual maximum daily temperature(TXx)and summer days(SU)in China and the JJJ region showed obvious increases by the end of the 21st century while there was a general reduction in frost days(FD).The ensemble of RegCM4 with different land surface components was used to examine population exposure to temperature extremes over the JJJ *** exposure to temperature extremes was found to decrease in 2091−99 relative to 1991−99 over the majority of the JJJ region due to the joint impacts of increases in temperature extremes over the JJJ and population decreases over the JJJ region,except for downtown ***,changes in population exposure to temperature extremes were mainly dominated by future population ***,we quantified changes in exposure to temperature extremes with temperature increase over the JJJ *** study helps to provide relevant policies to respond future climate risks over the JJJ region.

关键词： CMIP6 convection-permitting population exposure RegCM4 temperature extremes

The medium-temperature dependence of jet transport coefficient in high-energy nucleus-nucleus collisions

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Nuclear Science and Techniques 2024年第7期35卷 173-191页

作者： Man xie Qing-Fei han En-Ke Wang Ben-Wei Zhang han-Zhong Zhang Key Laboratory of Atomic and Subatomic Structure and Quantum Control(MOE) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of MatterInstitute of Quantum Matter South China Normal UniversityGuangzhou510006China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Guangdong Provincial Key Laboratory of Nuclear ScienceSouthern Nuclear Science Computing CenterSouth China Normal UniversityGuangzhou 510006China Key Laboratory of Quark and Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan430079China

The medium-temperature T dependence of the jet transport coefficient̂q was studied via the nuclear modification factor RAA(p_(T))and elliptical flow parameter v_(2)(p_(T))for large transverse momentum p_(T) hadrons in high-energy nucleus-nucleus *** a next-to-leading-order perturbative QCD parton model for hard scatterings with modified fragmentation functions due to jet quenching controlled by q,we check the suppression and azimuthal anisotropy for large p_(T) hadrons,and extract q by global fits to RAA(pT)and v_(2)(pT)data in A+A collisions at RHIC and LHC,*** numerical results from the best fits show that q∕T^(3) goes down with local medium-temperature T in the parton jet *** with the case of a constant q∕T^(3),the going-down T dependence of q∕T^(3) makes a hard parton jet to lose more energy near T_(c) and therefore strengthens the azimuthal anisotropy for large pT *** a result,v_(2)(p_(T))for large pT hadrons was enhanced by approximately 10%to better fit the data at RHIC/*** the first-order phase transition from QGP to the hadron phase and the additional energy loss in the hadron phase,v_(2)(p_(T))is again enhanced by 5-10%at RHIC/LHC.

关键词： Jet quenching Jet transport parameter Hadron suppression Elliptic flow coefficient Energy loss asymmetry

Learning Dual-Layer User Representation for Enhanced Item Recommendation

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Computers, Materials & Continua 2024年第7期80卷 949-971页

作者： Fuxi Zhu jin xie Mohammed Alshahrani Applied Research Center of Artificial Intelligence Wuhan CollegeWuhan430212China College of Computer Science South-Central MINZU UniversityWuhan430074China Unmanned.Company Riyadh11564Saudi Arabia

User representation learning is crucial for capturing different user preferences,but it is also critical challenging because user intentions are latent and dispersed in complex and different patterns of user-generated data,and thus cannot be measured ***-based data models can learn user representations by mining latent semantics,which is beneficial to enhancing the semantic function of user ***,these technologies only extract common features in historical records and cannot represent changes in user ***,sequential feature can express the user’s interests and intentions that change time by *** the sequential recommendation results based on the user representation of the item lack the interpretability of preference *** address these issues,we propose in this paper a novel model with Dual-Layer User Representation,named DLUR,where the user’s intention is learned based on two different layer ***,the latent semantic layer adds an interactive layer based on Transformer to extract keywords and key sentences in the text and serve as a basis for *** sequence layer uses the Transformer model to encode the user’s preference intention to clarify changes in the user’s ***,this dual-layer user mode is more comprehensive than a single text mode or sequence mode and can effectually improve the performance of *** extensive experiments on five benchmark datasets demonstrate DLUR’s performance over state-of-the-art recommendation *** addition,DLUR’s ability to explain recommendation results is also demonstrated through some specific cases.

关键词： User representation latent semantic sequential feature interpretability

Regulation of m^(6)Am RNA modification and its implications in human diseases

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Journal of Molecular Cell Biology 2024年第3期16卷 1-8页

作者： Hao jin Zhouyuanjing Shi Tianhua Zhou Shanshan xie Children’s Hospital Zhejiang University School of MedicineNational Clinical Research Center for Child HealthHangzhou 310052China Department of Cell Biology Zhejiang University School of MedicineHangzhou 310058China Department of Gastroenterology The Second Affiliated HospitalZhejiang University School of MedicineHangzhou 310020China Center for Medical Research and Innovation in Digestive System Tumors Ministry of EducationHangzhou 310020China

N6,2′-O-dimethyladenosine(m^(6)Am)is a prevalent modification frequently found at the 5′cap-adjacent adenosine of messenger RNAs(mRNAs)and small nuclear RNAs(snRNAs)and the internal adenosine of *** dynamic and reversible modification is under the regulation of methyltransferases phosphorylated CTD interacting factor 1 and methyltransferase-like protein 4,along with the demethylase fat mass and obesity-associated protein.m^(6)Am RNA modification plays a crucial role in the regulation of pre-mRNA splicing,mRNA stability,and translation,thereby influencing gene *** recent years,there has been growing interest in exploring the functions of m^(6)Am and its relevance to human *** this review,we provide a comprehensive overview of the current knowledge concerning m^(6)Am,with a focus on m^(6)Am-modifying enzymes,sequencing approaches for its detection,and its impacts on pre-mRNA splicing,mRNA stability,and translation ***,we highlight the roles of m^(6)Am in the context of obesity,viral infections,and cancers,unravelling its underlying regulatory mechanisms.

关键词： m^(6)Am RNA modification gene regulation obesity viral infection cancer

Geochemistry and origins of hydrogen-containing natural gases in deep Songliao Basin,China:Insights from continental scientific drilling

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Petroleum Science 2024年第2期21卷 741-751页

作者： Shuang-Biao han Chao-han Xiang Xin Du Lin-Feng xie Jie Huang Cheng-Shan Wang College of Geoscience and Surveying Engineering China University of Mining and TechnologyBeijing100083China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesBeijing100083China

The different reservoirs in deep Songliao Basin have non-homogeneous lithologies and include multiple layers with a high content of hydrogen *** gas composition and stable isotope characteristics vary significantly,but the origin analysis of different gas types has previously been *** on the geochemical parameters of gas samples from different depths and the analysis of geological settings,this research covers the diverse origins of natural gas in different *** gas components are mainly methane with a small amount of C_(2+),and non-hydrocarbon gases,including nitrogen(N_(2)),hydrogen(H_(2)),carbon dioxide(CO_(2)),and helium(He).At greater depth,the carbon isotope of methane becomes heavier,and the hydrogen isotope points to a lacustrine sedimentary *** increasing depth,the origins of N_(2)and CO_(2)change gradually from a mixture of organic and inorganic to *** origins of hydrogen gas are complex and include organic sources,water radiolysis,water-rock(Fe^(2+)-containing minerals)reactions,and *** shales of Denglouku and Shahezi Formations,as source rocks,provide the premise for generation and occurrence of organic ***,the deep faults and fluid activities in Basement Formation control the generation and migration of mantle-derived *** discovery of a high content of H_(2)in study area not only reveals the organic and inorganic association of natural-gas generation,but also provides a scientific basis for the exploration of deep hydrogen-rich gas.

关键词： Gas compositions Stable isotopes Gas origins Hydrogen gas Songliao Basin

Printable,flexible ceramic fiber paper based on electrospinning

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Rare Metals 2024年第6期43卷 2739-2746页

作者： Yong-Shuai xie Yuan Cheng Yang Lyu Rui Li Jie-Cai han National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

Based on the fact that it is challenging for the polymer flexible circuit substrates to meet the requirements of serving in high-temperature environments,this work proposed the idea of using printable ceramic fiber paper as a high-temperature flexible circuit substrate.A ceramic fiber paper with all ceramic components had been developed via electrospinning,solving the problems of low strength and severe strength drop at high temperatures of traditional ceramic fiber *** tensile strength of the prepared ceramic fiber paper is 2.63 MPa,and the reliable service temperature is 1200℃.Its bulk density is about 1.5 times that of traditional ceramic fiber *** can be printed with patterns by commercial inkjet printers like ordinary printing paper and has excellent *** feasibility of ceramic fiber paper as a flexible circuit substrate was verified by constructing a simple *** the fiber paper is significantly bent,the circuit still forms a complete path,which proves that it has a strong application potential for high-temperature flexible circuit substrate and is expected to promote the development of flexible electronic devices serving at extreme high-temperature environments.

关键词： Ceramic fiber paper High temperature Inkjet printing Flexible electronic

Real-time pore structure evolution difference between deep and shallow coal during gas adsorption:A study based on synchrotron radiation small-angle X-ray scattering

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Particuology 2024年第4期87卷 114-123页

作者： Yingfeng Sun Shuaipeng Zhu Fei xie Chujian han Yixin Zhao Zetian Zhang Research Institute of Macro-Safety Science University of Science and Technology BeijingBeijing100083China Schoolof Civiland Resource Engineering University of Science and Technology BeijingBeijing100083China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei230029China Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources China University of Mining and Technology(Beijing)Bejing10003 China School of Energy and Mining Engineering China University of Mining and Technology(Beijing)Beijing100083China Key Laboratory of Deep Earth Science and Engineering(Sichuan University) Ministry of EducationChengdu610065China

Coal seam CO_(2) sequestration is an important option to address global warming.A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO_(2) ***,few investigations on the pore structure evolution differences between the deep and shallow coal were conducted during gas *** this study,based on the real-time synchrotron radiation small-angle X-ray scattering(SAXS)observation,the average pore diameter and pore surface fractal dimension evolution differences between deep and shallow coal were investigated from the as-pects of coal compositions and stress *** types of coal deformation(inner-swelling and outer-swelling)coexist during gas *** compositions have significant impact on the dominance of deformation *** dominance of inner-swelling in deep coal is induced by the higher ash contents,and there is the decrease of average pore diameter during gas *** impact of stress-history(burial depth)on adsorption-induced deformation is more prominent than that of gas adsorption *** deep coal,the surface fractal dimension evolution presents a negative correlation with the evolution of pore *** shallow coal,the surface fractal dimension evolution presents a Langmuir-type correlation with the adsorption time.

关键词： Coal Gas adsorption Synchrotron radiation small-angle X-ray scattering Pore diameter Surface fractal dimension