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Carrying Capacity and Coupling Coordination of Water and Land Resources Systems in Arid and Semi-arid Areas: A Case Study of Yulin City, China

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Chinese Geographical Science 2024年第5期34卷 931-950页

作者： zhang Qianxi CAO zhi WANG Yongsheng HUANG Yijia Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Quantitatively assessing the carrying capacity of water and land resources systems in arid and semi-arid areas is crucial for achieving the 2030 Sustainable Development *** this work,taking Yulin City in China as a case study and employing the Criteria Importance Through Intercriteria Correlation(CRITIC)method,a modified model of coupling degree was developed to evaluate the car-rying capacity of water and land resources systems endowment and utilization,as well as their coupling coordination degree from 2013 to *** findings indicate that the water and land resources of Yulin are diminishing due to declines in agriculture,higher industrial water use,and wetland ***,reallocating domestic water for ecological sustainability and reducing sloping farmland can mitigate this trend of ***,as the coupling coordination between water and land resources system endowment in Yulin continuously improved,the coupling coordination between water and land resources system utilization first decreased and then in-creased with 2016 as the turning ***,the carrying capacity of water and land resources systems,the coupling coordination degree between water and land resources system endowment,and the coupling coordination degree between water and land resources system utilization in Yulin exhibited the same pattern of being higher in the six northern counties than in the six southern *** the water resources endowment is vital for the highly efficient use of water and land resources.

关键词： water and land resources systems carrying capacity coupling coordination human-earth system sustainable development Yulin City,China

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Construction of MoP/MoS_(2) Core-shell Structure Electrocatalyst for Boosting Hydrogen Evolution Reaction

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Chemical Research in Chinese Universities 2024年第3期40卷 490-498页

作者： MENG Dan ran Shunjiang GAO Ling zhang Yue SAN Xiaoguang zhang Lei LI Ruixiang JIN Quan College of Chemical Engineering Shenyang University of Chemical TechnologyShenyang 110142P.R.China Key Laboratory of Automobile Materials(Ministry of Education) School of Materials Science and EngineeringJilin UniversityChangchun 130022P.R.China

Hydrogen energy stands out as one of the most promising alternative energy sources due to its cleanliness and *** water splitting offers a sustainable pathway for hydrogen ***,the kinetic rate of the hydrogen evolution reaction(HER)is sluggish,emphasizing the critical need for stable and highly active electrocatalysts to facilitate HER and enhance reaction *** metal-based catalysts have garnered attention for their favorable catalytic activity in electrochemical hydrogen evolution in alkaline *** this investigation,flower-like nanorods of MoS_(2) were directly synthesized in situ on a nickel foam substrate,followed by the formation of MoP/MoS_(2)-nickel foam(NF)heterostructures through high-temperature phosphating in a tube furnace *** findings reveal that MoP/MoS_(2)-NF-450 exhibits outstanding electrocatalytic performance in an alkaline milieu,demonstrating a low overpotential(90 mV)and remarkable durability at a current density of 10 mA/cm^(2).Comprehensive analysis indicates that the introduction of phosphorus(P)atoms enhances the synergistic effect with MoS_(2),while the distinctive flower-like nanorod structure of MoS_(2) exposes more active ***,the interface between the MoP/MoS_(2) heterostructure and NF facilitates electron transfer during hydrogen evolution,thereby enhancing electrocatalytic *** design and synthesis of such catalysts offer a valuable approach for the development of high-performance hydrogen evolution electrocatalysts.

关键词： MoP/MoS_(2) Core-shell structure Heterostructure Synergistic effect Hydrogen evolution reaction

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Multi-scale hash encoding based neural geometry representation

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Computational Visual Media 2024年第3期10卷 453-470页

作者： zhi Deng Haoyao Xiao Yining Lang Hao Feng Juyong zhang School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China Alibaba Artificial Intelligence Governance Laboratory Alibaba GroupHangzhou 310017China

Recently, neural implicit function-basedrepresentation has attracted more and more attention,and has been widely used to represent surfacesusing differentiable neural networks. However, surfacereconstruction from point clouds or multi-view imagesusing existing neural geometry representations stillsuffer from slow computation and poor accuracy. Toalleviate these issues, we propose a multi-scale hashencoding-based neural geometry representation whicheffectively and efficiently represents the surface asa signed distance field. Our novel neural networkstructure carefully combines low-frequency Fourierposition encoding with multi-scale hash encoding. Theinitialization of the geometry network and geometryfeatures of the rendering module are accordinglyredesigned. Our experiments demonstrate that theproposed representation is at least 10 times faster forreconstructing point clouds with millions of *** also significantly improves speed and accuracyof multi-view reconstruction. Our code and modelsare available at https://***/Dengzhi-USTC/Neural-Geometry-Reconstruction.

关键词： neural geometry representation hash encoding point cloud reconstruction multi-view reconstruction

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Quasi-2D weak lensing cosmological constraints using the PDF-SYM method

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 44-58页

作者： Zhenjie Liu Jun zhang Hekun Li zhi Shen Cong Liu Department of Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

Cosmic shear statistics,such as the two-point correlation function(2PCF),can be evaluated with the PDF-SYM method instead of the traditional weighted-sum *** makes use of the full PDF information of the shear estimators,and does not require weightings on the shear estimators,which can in principle introduce additional systematic *** work presents our constraints on S8and?mfrom the shear-shear correlations using the PDF-SYM *** data we use is from the z-band images of the Dark Energy Camera Legacy Survey(DECa LS),which covers about 10000 deg2with more than 100 million *** shear catalog is produced by the Fourier Quad method,and well tested on the real data itself with the field-distortion *** main approach is called quasi-2D as we do use the photo-z information of each individual galaxy,but without dividing the galaxies into redshift *** mainly use galaxy pairs within the redshift interval between 0.2 and 1.3,and the angular range from 4.7 to 180 *** analysis yields S8=0.762±0.026 and?m=0.234±0.075,with the baryon effects and the intrinsic alignments *** results are robust against redshift *** check the consistency of our results by deriving the cosmological constraints from auto-correlations ofγ1andγ2separately,and find that they are consistent with each other,but the constraints from theγ1component are much weaker than that fromγ*** implies a much worse data quality ofγ1,which is likely due to additional shear uncertainties caused by CCD electronics(according to the survey strategy of DECa LS).We also perform a pure 2D analysis,which gives S8=0.81_(-0.04)^(+0.03)and?m=0.25_(-0.05)^(+0.06).Our findings demonstrate the potential of the PDF-SYM method for precision cosmology.

关键词： weak lensing shear-shear correlations cosmological parameters observations analysis

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Wettability regulation from superhydrophilic to superhydrophobic via nanosecond laser ablation

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Science China(Technological Sciences) 2024年第6期67卷 1829-1841页

作者： CHEN zhi WU zhiCheng zhang GuoJun LI DongHui HAN FengLin State Key Laboratory of Precision Manufacturing for Extreme Service Performance College of Mechanical and Electrical EngineeringCentral South UniversityChangsha410083China Guangdong Provincial Key Laboratory of Manufacturing Equipment Digitization Guangdong HUST Industrial Technology Research InstituteDongguan523808China China Harzone Industry Corp. Ltd.Wuhan430299China

Metal surfaces play a crucial role in numerous applications,from self-cleaning and anti-icing to anti-fogging and oil-water *** regulation of their wettability is essential to enhance their performance in these *** paper proposes a multi-state regulation method for metal surface wettability,leveraging nanosecond laser *** creating non-uniform microstructures on a metal surface,the contact area between the solid and liquid phases can be increased,resulting in the attainment of superhydrophilic properties(contact angle(CA),ranging from 4.6°to 8.5°).Conversely,the construction of uniform microstructures leads to a decreased solid-liquid contact area,thereby rendering the metal surface hydrophilic(CA=12.2°–53°).Furthermore,through heat treatment on a surface with uniform microstructures,organic matter adsorption can be promoted while simultaneously reducing surface *** process results in the metal surface acquiring hydrophobic properties(CA=92.1°–133.5°),facilitated by the“air cushion effect.”Building on the hydrophobic surface,stearic acid modification can further reduce surface energy,ultimately bestowing the metal surface with superhydrophobic properties(CA=150.1°–152.7°,and sliding angle=3.8°).Performance testing has validated the durability and self-cleaning effectiveness of the fabricated superhydrophobic surface while also highlighting the excellent anti-fog performance of the superhydrophilic *** findings strongly indicate the immense potential of these surfaces in various engineering applications.

关键词： nanosecond laser ablation surface wettability superhydrophobic superhydrophilic

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Synergistic Interdecadal Evolution of Precipitation over Eastern China and the Pacific Decadal Oscillation during 1951-2015

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Advances in Atmospheric Sciences 2024年第1期41卷 53-72页

作者： Minmin WU Rong-Hua zhang Junya HU Hai zhi Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Laosan Laboratory Qingdao 266237China School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China University of Chinese Academy of Sciences Beijing 100029China

By using the multi-taper method(MTM)of singular value decomposition(SVD),this study investigates the interdecadal evolution(10-to 30-year cycle)of precipitation over eastern China from 1951 to 2015 and its relationship with the North Pacific sea surface temperature(SST).Two significant interdecadal signals,one with an 11-year cycle and the other with a 23-year cycle,are identified in both the precipitation and SST *** show that the North Pacific SST forcing modulates the precipitation distribution over China through the effects of the Pacific Decadal Oscillation(PDO)-related anomalous Aleutian low on the western Pacific subtropical high(WPSH)and Mongolia high(MH).During the development stage of the PDO cold phase associated with the 11-year cycle,a weakened WPSH and MH increased the precipitation over the Yangtze River Basin,whereas an intensified WPSH and MH caused the enhanced rain band to move northward to North China during the decay *** the development stage of the PDO cold phase associated with the 23-year cycle,a weakened WPSH and MH increased the precipitation over North China,whereas an intensified WPSH and the weakened MH increased the precipitation over South China during the decay *** 11-year and 23-year variabilities contribute differently to the precipitation variations in the different regions of China,as seen in the 1998flooding *** 11-year cycle mainly accounts for precipitation increases over the Yangtze River Basin,while the 23-year cycle is responsible for the precipitation increase over Northeast *** results have important implications for understanding how the PDO modulates the precipitation distribution over China,helping to improve interdecadal climate prediction.

关键词： MTM-SVD PDO SST anomalies interdecadal variability precipitation over China

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Perception field based imitation learning for unlabeled multi-agent pathfinding

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Science China(Information Sciences) 2024年第5期67卷 115-135页

作者： Wenjie CHU Ailun YU Wei zhang Haiyan ZHAO zhi JIN School of Computer Science Peking University Key Laboratory of High-Confidence Software Technologies (Peking University) Ministry of Education

This paper proposes an imitation learning method to learn a universal agent policy for unlabeled multi-agent pathfinding(unlabeled MAPF) in grid environments. The method transforms the unlabeled MAPF problem into a series of temporal-independent homogeneous classification problems for each *** on this transformation, a neural network is designed to imitate a distance-optimal expert *** neural network consists of two successive modules: perception field learner and field integrating *** former refines and encodes the current system state into a perception field for each agent by combining a set of learnable field-generating functions. The latter takes an agent's perception field as input and decides the agent's next action based on a triplet cross-attention mechanism. We evaluate our method on a diverse set of unlabeled MAPF tasks. Compared with state-of-the-art counterparts, the experimental results manifest the superiority of the proposed method in both generalization ability and scalability.

关键词： unlabeled multi-agent pathfinding perception field triplet cross-attention multi-agent imitation learning learning-based planning

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Shear band evolution and acoustic emission characteristics of sandstone containing non-persistent flaws

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 497-513页

作者： Shuting Miao Peng-zhi Pan Chuanqing zhang Lei Huo State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China CASIC Research Institute of Intelligent Decision Engineering Wuhan430040China

Direct shear tests were conducted on sandstone specimens under different constant normal stresses to study the coalescence of cracks between non-persistent flaws and the shear sliding characteristics of the shear-formed *** image correlation and acoustic emission(AE)techniques were used to monitor the evolution of shear bands at the rock bridge area and microcracking *** experimental results revealed that the shear stresses corresponding to the peak and sub-peak in the stressdisplacement curve are significantly affected by the normal *** localization bands emerged at both the tip of joints and the rock bridge,and their extension and interaction near the peak stress caused a surge in the AE hit rate and a significant decrease in the AE b *** and curvilinear strain bands were detected at low normal stress,while high normal stress generally led to more microcracking events and longer coplanar cracks at the rock bridge ***,an increase in normal stress resulted in a higher AE count rate and more energetic AE events during friction sliding along the shearformed *** was observed that the elastic energy released during the crack coalescence at the prepeak stage was much greater than that released during friction sliding at the post-peak *** than 75%of AE events were located in the low-frequency band(0e100 kHz),and this proportion continued to rise with increasing normal ***,more AE events of low AF value and high RA value were observed in specimens subjected to high normal stress,indicating that greater normal stress led to more microcracks of shear nature.

关键词： Shear band evolution Acoustic emission(AE) Crack coalescence Normal stress Shear sliding

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Influence of friction-lubrication characteristics varying with rolling speed on instability of chatter and slip in cold tandem rolling process

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Journal of Iron and Steel Research International 2024年第4期31卷 894-908页

作者： Yan-li Xin zhi-ying Gao Bo Tian Qing-dong zhang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China

In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction ***,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is ***,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling *** one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is ***,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.

关键词： Cold tandem rolling:Oil film thickness Speed-dependent friction coefficient-Slip:Chatter

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Application of interpolated double network model for carbon nanotube composites in electrothermal shape memory behaviors

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Acta Mechanica Sinica 2024年第8期40卷 133-153页

作者： Ting Fu Zhao Yan Li zhang ran Tao Yiqi Mao Department of Engineering Mechanics College of Mechanical and Vehicle EngineeringHunan UniversityChangsha410082China State Key Laboratory of Explosion Science and Technology Institute of Advanced Structure TechnologyBeijing Institute of TechnologyBeijing100081China

Multi-wall carbon nanotube filled shape memory polymer composite(MWCNT/SMC)possessed enhanced modulus,strength,and electric conductivity,as well as excellent electrothermal shape memory properties,showing wide design scenarios and engineering application *** thermoelectrically triggered shape memory process contains complex multi-physical mechanisms,especially when coupled with finite deformation rooted on micro-mechanisms.A multi-physical finite deformation model is necessary to get a deep understanding on the coupled electro-thermomechanical properties of electrothermal shape memory composites(ESMCs),beneficial to its design and wide *** into consideration of micro-physical mechanisms of the MWCNTs interacting with double-chain networks,a finite deformation theoretical model is developed in this work based on two superimposed network chains of physically crosslinked network formed among MWCNTs and the chemically crosslinked *** intact crosslinked chemical network is considered featuring with entropic-hyperelastic properties,superimposed with a physically crosslinked network where percolation theory is based on electric conductivity and electric-heating *** model is calibrated by experiments and used for shape recoveries triggered by heating and electric *** captures the coupled electro-thermomechanical behavior of ESMCs and provides design guidelines for MWCNTs filled shape memory polymers.

关键词： Shape memory polymer composite Viscoplastic constitutive relations Electro-thermomechanics Double network model Multiple shape memory

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