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Almost periodic solutions of memristive multidirectional associative memory neural networks with mixed time delays

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International Journal of Biomathematics 2024年第2期17卷 113-138页

作者： Yan Zhang Yuanhua qiao Lijuan Duan Faculty of Science Beijing University of Technology Beijing 100124P.R.China Faculty of Information Technology Beijing University of Technology Beijing 100124P.R.China

Traditional biological neural networks cannot simulate the real situation of the abrupt synaptic connections between neurons while modeling associative memory of human *** this paper,the memristive multidirectional associative memory neural networks(MAMNNs)with mixed time-varying delays are investigated in the sense of Filippov ***,three steps are given to prove the existence of the almost periodic *** new lemmas are proposed to prove the boundness of the solution and the asymptotical almost periodicity of the solution by constructing Lyapunov ***,the uniqueness and global exponential stability of the almost periodic solution of memristive MAMNNs are investigated by a new Lyapunov *** sufficient conditions guaranteeing the properties of almost periodic solution are derived based on the relevant definitions,Halanay inequality and Lyapunov *** investigation is an extension of the research on the periodic solution and almost periodic solution of bidirectional associative memory neural ***,numerical examples with simulations are presented to show the validity of the main results.

关键词： Almost periodic solutions memristive multidirectional associative memory neural networks mixed time-varying delays global exponential stability

Simulation of Underground Reservoir Stability of Pumped Storage Power Station Based on Fluid-Structure Coupling

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1381-1399页

作者： Peng qiao Shuangshuang Lan Hongbiao Gu Zhengtan Mao Faculty of Architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing100020China College of Transportation Engineering Nanjing Tech UniversityNanjing210000China

Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its construction environment is more complex than that of a traditional *** particular,the stability of the rock strata in the underground reservoirs is affected by the seepage pressure and rock stress,which presents some challenges in achieving engineering safety and *** the advantages of the numerical simulation method in dealing deal with nonlinear problems in engineering stability,in this study,the stability of the underground reservoir of the Shidangshan(SDS)pumped storage power station was numerically calculated and quantitatively analyzed based on fluid-structure coupling theory,providing an important reference for the safe operation and management of the underground ***,using the COMSOL software,a suitablemechanicalmodel was created in accordance with the geological structure and project characteristics of the underground ***,the characteristics of the stress field,displacement field,and seepage field after excavation of the underground reservoir were simulated in light of the seepage effect of groundwater on the nearby rock of the underground ***,based on the construction specifications and Molar-Coulomb criterion,a thorough evaluation of the stability of the underground reservoir was performed through simulation of the filling and discharge conditions and anti-seepage strengthening *** findings demonstrate that the numerical simulation results have a certain level of reliability and are in accordance with the stress measured in the project *** underground reservoir excavation resulted in a maximum displacement value of the rock mass around the caverns of 3.56 mm in a typical section,and the safety coefficient of the parts,as determined using the Molar-Coulomb criterion,was highe

关键词： Underground reservoir fluid-structure coupling numerical simulation pumped storage power station filling and discharge

Reliability Analysis of Reinforcement Based on GM(1,1)-Markov Semi-immersion Test

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1177-1187页

作者： FU Yong qiao Hongxia HAKUZWEYEZU Theogene School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Gansu Advanced Civil Engineering Materials Engineering Research Center Lanzhou 730050China State Key Laboratory of Geomechanics and Geotechnical Enginering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China Civil Engineering Department University of Chinese Academy of SciencesBeijing 100049China

To investigate the corrosion degradation law and service life of reinforced concrete in various salt solution environments,reinforced concrete specimens were semi-immersed in 3%Na_(2)CO_(3)(N3-0-0),3%Na_(2)CO_(3)+3%NaCl(N3-Cl3-0)and 3%Na_(2)CO_(3)+3%NaCl+3%Na_(2)SO_(4)(N3-Cl3-S3)salt *** electrochemical workstation was used for regular non-destructive testing,and the polarization curve and related electrochemical parameters were used as the macroscopic durability evaluation indicators,while microscopic analysis of steel bar corrosion products was performed in combination with SEM and *** addition,the corrosion current density degradation model of GM(1,1)was established and compared with the modified GM(1,1)-Markov degradation *** results showed that the prediction error of the GM(1,1)-Markov model was smaller and more accurate than that of GM(1,1).The reinforced concrete specimens in the N3-0-0,N3-Cl3-0 and N3-Cl3-S3 solutions reached the failure state in 3.08,1.67,and 2.30 years,respectively,as predicted by the GM(1,1)-Markov *** to ESM and EDS microscopic analysis of reinforcement,carbonate had no significant effect on reinforcement corrosion,chloride ions played a dominant role in reinforcement corrosion,and sulfate ion improved concrete's resistance to chloride ion *** on GM(1,1)-Markov model,the failure and damage of reinforced concrete in saline soil areas can be quantitatively evaluated in the whole life cycle,which provides a theoretical basis for the early maintenance or reinforcing of reinforced concrete.

关键词： salt solution semi-immersion corrosion current density GM(1,1)-Markov

A hybrid attention model based on first-order statistical features for smoke recognition

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Science China(Technological Sciences) 2024年第3期67卷 809-822页

作者： GUO Nan LIU JiaHui DI KeXin GU Ke qiao JunFei Beijing Laboratory of Smart Environmental Protection Beijing Key Laboratory of Computational Intelligence and Intelligent SystemBeijing Artificial Intelligence InstituteBeijing 100124China Faculty of Information Technology Beijing University of TechnologyBeijing 100124China

Smoke and fire recognition are of great importance on foreseeing fire disasters and preventing environmental pollution by monitoring the burning process of objects(e.g., straw, fuels). However, since fire images suffer from problems like the variability of the features, complexity of scenarios, interference from background, changeable weather conditions as well as image quality problems, identifying smoke and fire accurately and promptly from a given image still remains a substantial challenge. Automatically learning the features of smoke images by CNNs has improved the target recognition ability compared to traditional approaches,nonetheless, convolutions and pooling operations in CNNs may cause severe information loss which may lead to *** tackle the above problems, this paper proposed a hybrid attention model based on the characteristics of smoke images. This model adopted multiple optimized attention mechanism in several stages to quickly and precisely capture the important features,achieving state-of-the-art performance on smoke and fire recognition in terms of accuracy and speed. Our proposed module mainly consists of two stages: pooling and attention. In the first stage, we conducted several newly proposed first-order pooling methods. Through traversing the data space in a larger scope, features are better reserved, thus constructing a more intact feature space of smoke and fire in an image. In the second stage, feature maps are aggregated together to perform channel and spatial attention. The channel and spatial dependencies allow us to quickly catch the important features presented in an image. By fully exploring the feature space and prominent salient features, characteristics of smoke and fire are better presented so as to obtain better smoke and fire detection results. Experiments have been conducted on public smoke detection dataset and new proposed fine-grained smoke and fire detection database. Experimental results revealed that the propose

关键词： hybrid attention first-order pooling smoke and fire detection deep convolutional neural networks

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Construction and manipulation of origami-inspired tubular structures with controlled mechanical buckling for collection and transportation of microspheres based on optically induced electrokinetics

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Science China(Technological Sciences) 2024年第9期67卷 2954-2964页

作者： YANG WenGuang WANG WenHao TENG XiangYu qiao ZeZheng YU HaiBo School of Electromechanical and Automotive Engineering Yantai UniversityYantai 264005China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China

The development of microengineered hydrogels has opened up unlimited possibilities for designing complex structures at the microscale. In this study, we constructed an origami-inspired tubular structure with controlled mechanical buckling based on optically induced electrokinetics(OEK). By inducing a stress gradient in the thickness, a tubular structure can be formed from a poly(ethylene glycol) diacrylate(PEGDA) hydrogel film of various shapes that have been custom fabricated. To achieve an ideal three-dimensional(3D) structure, the amplitude of the tubular structure can be controlled by adjusting the aspect ratios or polymerization time. Furthermore, the tubular structure can be manipulated for the collection and transportation of *** summary, we provide an effective method for designing 3D structures at the micro-nano scale. This forming method holds great potential for achieving various functions in tissue engineering, drug packaging, and transportation in the future.

关键词： origami-inspired tubular structures optically induced electrokinetics microfabrication mechanical buckling

Surface pollen and modern vegetation in Southern Xinjiang,China

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Science China Earth Sciences 2024年第2期67卷 510-530页

作者： Yun ZHANG Lixin CHEN Yaoyao XI Zhaochen KONG Xianguo qiao State Key Laboratory of Black Soils Conservation and Utilization Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun130102China Institute of Botany Chinese Academy of SciencesBeijing100093China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China University of Chinese Academy of Sciences Beijing100049China School of Geosciences and Resources China University of Geosciences(Beijing)Beijing100083China

The study of modern pollen,and vegetation can improve the accuracy of paleoenvironmental reconstruction based on fossil pollen data.A total of 188 pollen surface samples were collected from Southern Xinjiang(34°00’–43°00’N,74°00’–94°00’E)in China,with an elevation range of 888–4530 *** pollen and vegetation were studied in the northern region of the Kunlun Mountains and the southern region of the Tianshan *** results showed that the surface pollen assemblages on the southern slope of the Tianshan Mountains(3530–1124 m)were divided into three pollen zones,namely,montane steppe,montane desert steppe,and montane *** zones were dominated by Artemisia,Chenopodiaceae,and Ephedra *** surface pollen assemblages in the eastern Pamir Plateau(4530–1287 m)could be divided into alpine meadow,montane desert steppe,and montane desert zones,which were predominantly characterized by Artemisia,Chenopodiaceae,and Asteraceae ***,the Southern Tarim Basin(3548–888 m)comprised montane desert steppe and montane desert zones,which was dominated by Artemisia and Chenopodiaceae *** geographic distribution of the surface pollen sites obtained using ArcGIS,the R-value,and Pearson correlation analyses indicated that the over-represented Picea and Pinus pollen were of external origin and were transported by wind,water(rivers),and ice(glacier movement).Over-representation of Ephedra and Nitraria pollen was mainly distributed in the montane desert and desert steppe zones,*** from Chenopodiaceae and Artemisia were over-represented and broadly distributed across Southern *** pollen was concentrated in areas with walnut trees,strongly indicating the presence of local parent *** to the Hybrid Singleparticle Lagrangian Integrated Trajectory model,more Pinus pollen was transported to the Pamir region by external airflows during spring and summer,resulting in its higher surface pollen *** elucidating t

关键词： Surface pollen Vegetation Distribution Picea Southern Xinjiang

Atomistic study of inverse size effect induced by interfacial plasticity in pearlitic multi-principal element alloy

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Rare Metals 2024年第7期43卷 3341-3355页

作者： Chen Yang qiao-Sheng Xia Cun-Hong Yin Dong-Peng Hua College of Mechanical Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Advanced Manufacturing Technology Ministry of EducationGuizhou UniversityGuiyang 550025China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China

Owing to the fine nano-laminated structure,the pearlitic multi-principal element alloy(PMPEA) exhibits excellent mechanical and tribological ***,the incomplete understanding of the size effect of its lamella thickness and the unclear understanding of the plasticity-interface interaction mechanism limit further optimization of *** this study,the FeCoNi/Ni_3Ti interface-mediated plastic deformation behavior in PMPEA and the variation of mechanical and tribological properties with lamella thickness within the nanoscale range using molecular dynamics(MD) simulation were *** results indicate that the mechanical and tribological properties of the PMPEA with lamella thicknesses below 10 nm have a significant inverse size effect,i.e.,the smaller the lamella thickness,the weaker the *** is because the plastic carrier-interface interaction mechanism changes from a strengthening mechanism that hinders dislocations to a weakening mechanism that promotes dislocations with the decreases in the lamella thickness,and the weakening effect becomes more pronounced as the lamella thickness decreases and the number of interfaces *** particular,the deformation behavior of Ni_3Ti lamellae changes from crystal-like to amorphous-like with decreasing ***,in the sample with larger lamella thickness,the occurrence of hierarchical slips in the body-centered cubic(BCC) phase due to the multiprincipal elements effect can better alleviate the stress concentration caused by the dislocation accumulation at the interface,so that the phase interface exhibits outstanding load-bearing *** the dislocation pattern in BCC phase shows a firm high-density cell,which makes the substrate exhibit a stable tribological response.

关键词： Multi-principal element alloy Nano-laminated structure Molecular dynamics simulation Nanoindentation and nanoscratch

Understanding and improving Yangtze River Basin summer precipitation prediction using an optimal multi-Physics ensemble

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Frontiers of Earth Science 2024年第1期18卷 256-277页

作者： Yang ZHAO Fengxue qiao Xin-Zhong LIANG Jinhua YU Climate Environment and Sustainability CenterNanjing University of Information Science and TechnologyNanjing 210044China Key Laboratory of Geographic Information Science(Ministry of Education) East China Normal UniversityShanghai 200241China School of Geographic Sciences East China Normal UniversityShanghai 200241China Department of Atmospheric and Oceanic Science University of MarylandCollege Park MD 20740USA Earth System Science Interdisciplinary Center University of MarylandCollege Park MD 20740USA Key Laboratory of Meteorological Disaster(KLME)(Ministry of Education)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science and TechnologyNanjing 210044China

This study employs the regional Climate-Weather Research and Forecasting model(CWRF)to first investigate the primary physical mechanisms causing biases in simulating summer precipitation over the Yangtze River Basin(YRB),and then enhance its predictive ability through an optimal multi-physics ensemble *** CWRF 30-km simulations in China are compared among 28 combinations of varying physics parameterizations during 1980−***-term average summer biases in YRB precipitation are remotely correlated with those of large-scale *** teleconnections of biases are highly consistent with the observed correlation patterns between interannual variations of precipitation and circulations,despite minor shifts in their primary action *** YRB precipitation aligns with a southward shifted East Asian westerly jet,an intensified low-level southerly flow south of YRB,and a south-eastward shifted South Asian high,alongside higher moisture availability over ***,decreased YRB precipitation corresponds to an opposite circulation *** CWRF control configuration using the ensemble cumulus parameterization(ECP),compared to other cumulus schemes,best captures the observed YRB precipitation characteristics and associated circulation *** ECP with the Morrison or Morrison-aerosol microphysics and the CCCMA or CAML radiation schemes enhances the overall CWRF *** to the control CWRF,the ensemble average of these skill-enhanced physics configurations more accurately reproduces YRB summer precipitation’s spatial distributions,interannual anomalies,and associated circulation *** Bayesian Joint Probability calibration to these configurations improves the ensemble’s spatial distributions but compromises its interannual anomalies and teleconnection *** findings highlight substantial potential for refining the representation of climate system physics to improve YRB precipitation *** is notabl

关键词： physics parameterization regional climate model downscaling skill enhancement multi-physics ensemble teleconnection bias reduction

Acyclic Edge Coloring of 1-planar Graphs without 4-cycles

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 35-44页

作者： Wei-fan Wang Yi-qiao Wang Wan-shun Yang Department of Mathematics Zhejiang Normal UniversityJinhua321004China School of Management Beijing University of Chinese MedicineBeijing100029China School of Mathematics and Information Science Weifang UniversityWeifang261061China

An acyclic edge coloring of a graph G is a proper edge coloring such that there are no bichromatic cycles in *** acyclic chromatic index χ'α(G) of G is the smallest k such that G has an acyclic edge coloring using k *** was conjectured that every simple graph G with maximum degree Δ has χ'_α(G) ≤Δ+2.A1-planar graph is a graph that can be drawn in the plane so that each edge is crossed by at most one other *** this paper,we show that every 1-planar graph G without 4-cycles has χ'_α(G)≤Δ+22.

关键词： 1-planar graph acyclic edge coloring acyclic chromatic index