检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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

Aerodynamic Performance of Three Flapping Wings with Unequal Spacing in Tandem Formation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2024年第4期21卷 1662-1676页

作者： Min chang Ziyi Xu Zengshuang Chen Li Li Xueguang Meng Unmanned System Research Institute National Key Laboratory of Unmanned Aerial Vehicle TechnologyNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an710049People’s Republic of China Xi’an Aeronautics Computing Technique Research Institute Aviation Industry Corporation of ChinaXi’an710076People’s Republic of China

To better understand the aerodynamic reasons for highly organized movements of flying organisms,the three-flapping wing system in tandem formation was studied numerically in this *** from previous relevant studies on the multiple flapping wings that are equally spaced,this study emphasizes the impact of unequal spacing between individuals on the aerodynamics of each individual wing as well as the whole *** is found that swapping the distance between the first and second wing with the distance between the second wing and the rearmost wing does not affect the overall aerodynamic performance,but significantly changes the distribution of aerodynamic benefits across each *** the whole flapping cycle,three effects are at *** narrow channel effect and the downwash effect can promote and weaken the wing lift,respectively,while the wake capture effect can boost the *** also shows that these effects could be manipulated by changing the spacing between adjacent *** findings provide a novel way for flow control in tandem formation flight and are also inspiring for designing the formation flight of bionic aircraft.

关键词： Three flapping wings Unequal spacing Aerodynamic performance Tandem formation

Incorporating metapath interaction on heterogeneous information network for social recommendation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第1期18卷 33-48页

作者： Yanbin JIANG Huifang MA Xiaohui ZHANG Zhixin LI Liang chang College of Computer Science and Engineering Northwest Normal UniversityLanzhou 730070China Guangxi Key Lab of Multi-source Information Mining and Security Guangxi Normal UniversityGuilin 541001China Guangxi Key Laboratory of Trusted Software Guilin University of Electronic TechnologyGuilin 541004China

Heterogeneous information network(HIN)has recently been widely adopted to describe complex graph structure in recommendation systems,proving its effectiveness in modeling complex graph *** existing HIN-based recommendation studies have achieved great success by performing message propagation between connected nodes on the defined metapaths,they have the following major *** works mainly convert heterogeneous graphs into homogeneous graphs via defining metapaths,which are not expressive enough to capture more complicated dependency relationships involved on the ***,the heterogeneous information is more likely to be provided by item attributes while social relations between users are not adequately *** tackle these limitations,we propose a novel social recommendation model MPISR,which models MetaPath Interaction for Social Recommendation on heterogeneous information ***,our model first learns the initial node representation through a pretraining module,and then identifies potential social friends and item relations based on their similarity to construct a unified *** then develop the two-way encoder module with similarity encoder and instance encoder to capture the similarity collaborative signals and relational dependency on different *** experiments on five real datasets demonstrate the effectiveness of our method.

关键词： heterogeneous information network social reco-mmender system metapath interaction attention mechanism

Fourth-order phase-field modeling for brittle fracture in piezoelectric materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 837-856页

作者： Yu TAN Fan PENG chang LIU Daiming PENG Xiangyu LI State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Science Chang'an UniversityXi'an 710064China Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Failure analyses of piezoelectric structures and devices are of engineering and scientific *** this paper,a fourth-order phase-field fracture model for piezoelectric solids is developed based on the Hamilton *** typical electric boundary conditions are involved in the present model to characterize the fracture behaviors in various physical situations.A staggered algorithm is used to simulate the crack *** polynomial splines over hierarchical T-meshes(PHT-splines)are adopted as the basis function,which owns the *** numerical simulations are performed to study the influence of the electric boundary conditions and the applied electric field on the fracture behaviors of piezoelectric *** electric boundary conditions may influence crack paths and fracture loads *** present research may be helpful for the reliability evaluation of the piezoelectric structure in the future applications.

关键词： isogeometric analysis(IGA) brittle fracture fourth-order phase-field model piezoelectric solid

Effect of bipolar-plates design on corrosion,mass and heat transfer in proton-exchange membrane fuel cells and water electrolyzers:A review

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1599-1616页

作者： Jiuhong Zhang Xiejing Luo Yingyu Ding Luqi chang Chaofang Dong Key Laboratory for Corrosion and Protection(MOE) Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Beijing Advanced Innovation Center for Materials Genome Engineering Beijing 100083China

Attaining a decarbonized and sustainable energy system,which is the core solution to global energy issues,is accessible through the development of hydrogen ***-exchange membrane water electrolyzers(PEMWEs)are promising devices for hydrogen production,given their high efficiency,rapid responsiveness,and *** plates account for a relatively high percentage of the total cost and weight compared with other components of ***,optimization of their design may accelerate the promotion of *** paper reviews the advances in materials and flow-field design for bipolar ***,the working conditions of proton-exchange membrane fuel cells(PEMFCs)and PEMWEs are compared,including reaction direction,operating temperature,pressure,input/output,and ***,the current research status of bipolar-plate substrates and surface coatings is summarized,and some typical channel-rib flow fields and porous flow fields are ***,the effects of materials on mass and heat transfer and the possibility of reducing corrosion by improving the flow field structure are ***,this review discusses the potential directions of the development of bipolar-plate design,including material fabrication,flow-field geometry optimization using threedimensional printing,and surface-coating composition optimization based on computational materials science.

关键词： bipolar-plates flow design mass and heat transfer corrosion water electrolyzers fuel cells

Copper coordination-driven self-assembly and encapsulation of PCR reagents

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 189-192页

作者： chang Lu Jinkai Zheng Juewen Liu Institute of Food Science and Technology Chinese Academy of Agricultural SciencesBeijing 100193China Department of Chemistry Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooONN2L 3G1Canada

Polymerase chain reactions(PCR)are a very important tool for use in cloning,nucleic acid sequencing and diagnostic *** storage conditions of PCR reagents are limited to freezing and a lot of mixing steps are *** this paper,we report using metal ions to form coordination nanomaterials with the intrinsic components of the PCR reagents including dNTP,DNA primers and DNA polymerase as an integrated PCR reaction *** complete PCR reactions,users need only to dissolve the coordination nanomaterials with a buffer and add template DNA.A few transition metal ions were screened and Cu^(2+)was found to be the most effective metal ion for this *** the encapsulation efficiency of PCR reagents was measured,which can reach close to 100%for the primers and DNA polymerase,but only 10%for dNTP because dNTP was *** study also exhibited this integrated PCR reaction system can be used for DNA detection with a similar detection limit to the normal PCR,and showed good stability of encapsulated PCR nanomaterial after storage for a week.

关键词： Metal ions Coordination Encapsulation PCR Storage

An online value iteration method for linear-quadratic mean field social control with unknown dynamics

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第4期67卷 38-39页

作者： Bing-chang WANG Shumei LI Ying CAO School of Control Science and Engineering Shandong University

Mean field(MF) models have been widely applied to economics, control theory, and other fields. Its prominent feature is that the individual influence on the overall population is negligible and the impact of the entire system to the single agent is significant and cannot be ignored. As a classical problem in control theory, linear quadratic(LQ) control for MF models has been widely investigated(e.g., [1, 2]).

关键词：

Cell Consistency Evaluation Method Based on Multiple Unsupervised Learning Algorithms

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Big Data Mining and Analytics 2024年第1期7卷 42-54页

作者： Jiang chang Xianglong Gu Jieyun Wu Debu Zhang Stellantis China Technology Center Shanghai 200233China

Unsupervised learning algorithms can effectively solve sample *** address battery consistency anomalies in new energy vehicles,we adopt a variety of unsupervised learning algorithms to evaluate and predict the battery consistency of three vehicles using charging fragment data from actual operating *** extract battery-related features,such as the mean of maximum difference,standard deviation,and entropy of batteries and then apply principal component analysis to reduce the dimensionality and record the amount of preserved *** then build models through a collection of unsupervised learning algorithms for the anomaly detection of cell consistency *** also determine whether unsupervised and supervised learning algorithms can address the battery consistency problem and document the parameter tuning *** addition,we compare the prediction effectiveness of charging and discharging features modeled individually and in combination,determine the choice of charging and discharging features to be modeled in combination,and visualize the multidimensional data for fault *** results show that the unsupervised learning algorithm is effective in visualizing and predicting vehicle core conformance faults,and can accurately predict faults in real ***“distance+boxplot”algorithm shows the best performance with a prediction accuracy of 80%,a recall rate of 100%,and an F1 of *** proposed approach can be applied to monitor battery consistency faults in real time and reduce the possibility of disasters arising from consistency faults.

关键词： battery consistency charging segment data unsupervised learning

Neurotoxicity of tetramethylammonium ion on larval and juvenile zebrafish:Effects on neurobehaviors and multiple biomarkers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第9期143卷 138-147页

作者： Ruixin Zhang Rui Wang Jiajun chang GDaniel Sheng Daqiang Yin Key Laboratory of Yangtze River Water Environment Ministry of EducationCollege of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Tetramethylammonium hydroxide(TMAH)is an important compound that utilized and released by the rapidly expanding semiconductor industry,which could hardly be removed by the conventional wastewater treatment *** a cholinergic agonist,the tetramethylammonium ion(TMA^(+))has been reported to induce toxicity to muscular and respiratory systems of mammals and human,however the toxicity on aquatic biota remains poorly *** investigated the neurotoxic effects of TMA^(+)exposure on zebrafish,based on neurobehavior tests and a series of *** inhibitions on the swimming distance of zebrafish larvae were observed when the exposure level exceeded 50 mg/L,and significant alterations on swimming path angles(straight and deflective movements)occurred even at 10 mg/*** tested neurobehavioral endpoints of zebrafish larvae were significantly positively correlated with reactive oxygen species(ROS)and malondialdehyde(MDA),significantly negatively related with the activities of antioxidant enzymes,but not significantly correlated with the level of acetylcholinesterase(AChE).Such relationship indicates that the observed neurotoxic effects on swimming behavior of zebrafish larvae is mainly driven by oxidative stress,rather than the alterations of *** the highest exposure concentration(200 mg/L),TMA^(+)evoked more severe toxicity on zebrafish juveniles,showing significantly stronger elevation on the MDA activity,and greater inhibitions on the activities of antioxidant enzymes and ACh E,suggesting juveniles were more susceptible to TMA^(+)exposure than larval zebrafish.

关键词： Tetramethylammonium Zebrafish Oxidative stress Acetylcholinesterase Neurobehavior