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Flow field, sedimentation, and erosion characteristics around folded linear HDPE sheet sand fence: Numerical simulation study

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Journal of Mountain Science 2024年第1期21卷 113-130页

作者： ZHANG Kai ZHANG Hailong TIAN Jianjin QU Jianjun ZHANG Xingxin WANG Zhenghui XIAO jianhua College of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730000China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China College of Civil Engineering Chongqing UniversityChongqing 400045China Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

Wind and sand hazards are serious in the Milan Gobi area of the Xinjiang section of the Korla Railway. In order to ensure the safe operation of railroads, there is a need for wind and sand protection in heavily sandy areas. The wind and sand flow in the region is notably bi-directional. To shield railroads from sand, a unique sand fence made of folded linear high-density polyethylene(HDPE) is used, aligning with the principle that the dominant wind direction is perpendicular to the fence. This study employed field observations and numerical simulations to investigate the effectiveness of these HDPE sand fences in altering flow field distribution and offering protection. It also explored how these fences affect the deposition and erosion of sand particles. Findings revealed a significant reduction in wind speed near the fence corner;the minimum horizontal wind speed on the leeward side of the first sand fence(LSF) decreased dramatically from 3 m/s to 0.64 m/s. The vortex area on the LSF markedly impacted horizontal wind speeds. Within the LSF, sand deposition was a primary occurrence. As wind speeds increased, the deposition zone shrank, whereas the positive erosion zone expanded. Close to the folded corners of the HDPE sand fence, there was a notable shift from the positive erosion zone to a deposition zone. Field tests and numerical simulations confirmed the high windproof efficiency(WE) and sand resistance efficiency(SE) in the HDPE sand fence. Folded linear HDPE sheet sand fence can effectively slow down the incoming flow and reduce the sand content, thus achieving good wind and sand protection. This study provides essential theoretical guidance for the design and improvement of wind and sand protection systems in railroad engineering.

关键词： Folded linear HDPE sheet sand fence Numerical simulation Flow field characteristics Protection benefits

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Exploration of the Mining of Ideological and Political Elements and Teaching Integration of Bridge Engineering Courses in Applied Undergraduate Programs

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Journal of Contemporary Educational Research 2024年第9期8卷 210-218页

作者： Huali Jiao Liming Zhao School of Civil Engineering and Architecture Chongqing Institute of EngineeringChongqing 400056China

The questions of what kind of individuals university education should cultivate,how to cultivate them,and for whom they are being trained are pressing issues that require immediate *** ideological and political education is a fundamental way to address these *** political education into professional courses is just as important as imparting knowledge,fostering interest,transmitting values,and shaping students’character and *** excavation of ideological and political elements in bridge engineering courses should comprehensively consider the dependent subject of ideological and political elements,the source of cases,the depth of excavation,the trade-offs between courses,the commonality and multifaceted nature of ideological and political elements,as well as the two ways of ideological and political elements *** and political elements should be integrated into all stages of classroom lectures,course assignments,final examinations,course design,discipline competitions,school-enterprise cooperation,etc.,so as to achieve the effect of educating people in the whole process.

关键词： Ideological and political teaching Bridge engineering Ideological and political elements mining Integration of ideology and politics

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MOF-derived Cu embedded into N-doped mesoporous carbon as a robust support of PdAu nanocatalysts for ethanol electrooxidation

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Rare Metals 2024年第3期43卷 1083-1094页

作者： Yu-Fu Huang Peng Wu Jun-Ping Tang Jian Yang Jing Li Shuai Chen Xue-Ling Zhao ChengChen Bin-Wei Zhang Yan-Yun Ma Wei-Heng Shi Dong-Hai Lin Shi-Gang Sun School of Energy and Materials Shanghai Engineering Research Center of Advanced Thermal Functional MaterialsShanghai Key Laboratory of Engineering Materials Application and EvaluationShanghai Polytechnic UniversityShanghai201209China State Key Laboratory of Physical Chemistry of Solid Surfaces Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China School of Chemistry and Chemical Engineering Chongqing UniversityChongqing401331China Center of Advanced Energy Technology and Electrochemistry Institute of Advanced Interdisciplinary StudiesChongqing UniversityChongqing400044China institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&DevicesSoochow UniversitySuzhou215123China Department of Materials Science and Engineering Drexel UniversityPhiladelphiaPA19104USA

Metal-organic frameworks(MOFs)h ave attracted widespread attention due to their large surface area and porous *** designing the nanostructures of MOFs to promote their application in ethanol electrooxidation is still a ***,a novel Cu-NCNs(Cu-nitrogen-doped carbon nanotubes)support was synthesized by pyrolysis of melamine(MEL)and Cu-ZIF-8 together,and then,Pd-Au nanoalloys were loaded by sodium borohydride reduction method to prepare PdAu@Cu-NCNs *** generating mesoporous carbon with high specific surface area and favorable electron and mass transport can be used as a potential excellent carrier for PdAu *** addition,the balance of catalyst composition and surface structure was tuned by controlling the content of Pd and ***,the best-performed Pd_(2)Au_(2)@Cu-NCN-1000-2(where 1000 means the carrier calcination temperature,and 2 means the calcination constant temperature time)catalyst exhibits better long-term stability and electrochemical activity for ethanol oxidation in alkaline media(4.80 A·mg^(-1)),which is 5.05 times higher than that of commercial Pd/C(0.95 A·mg^(-1)).Therefore,this work is beneficial to further promoting the application of MOFs in direct ethanol fuel cells(DEFCs)and can be used as inspiration for the design of more efficient catalyst support structures.

关键词： Metal-organic frameworks(MOFs) N-doped Mesoporous carbon PdAu Ethanol electrooxidation

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Research on the Evaluation System of Community Daycare Center planning and Implementation from the Perspective of Subject-Object Relationships

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Journal of Architectural Research and Development 2024年第3期8卷 117-127页

作者： Tijin Gui School of Civil Engineering and Architecture Chongqing Institute of EngineeringChongqing 400056China

Through literature review,we found that evaluations of urban planning implementation often focus narrowly on either the subject(stakeholders)or the object(projects),while micro-level aspects such as site selection and construction are primarily considered within the context of planning *** is insufficient research on the evaluation of *** daycare centers play a crucial role in the community home care model,yet there is relatively little research on their usage efficiency,satisfaction levels,and spatial evaluation of planning *** on the theoretical understanding of the human environment,including the subject,object,and their interactions,an evaluation system for the planning and implementation of community day care centers was constructed,incorporating subjective evaluation,objective evaluation,and comparative analysis.

关键词： Subject-object relationship Daycare center planning implementation Evaluation system

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Research on Adaptability Analysis of Environmental Space Demand and design Optimization of Daycare Centers: Taking chongqing’s Community F as an Example

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Journal of World Architecture 2024年第3期8卷 49-56页

作者： Tijin Gui Minna Yu Bin Chen Jun Tao chongqing institute of Engineering School of Civil Engineering and ArchitectureChongqing 400056China

Currently,there is a lack of research on the detailed environmental spatial design of community daycare centers at the micro *** study focuses on Community F in chongqing,using the elderly’s“willingness to demand”as a central *** examines indoor and outdoor environmental space needs at a micro level,considering both functional requirements and spiritual needs based on existing *** analysis incorporates three adaptive elements:current construction,surrounding environment,and operational *** explores the feasibility of restructuring spatial layouts,utilizing local resources,and integrating Bayu cultural ***,through design optimization practices,the study proposes three strategies for aging optimization:functional integration and interaction,user-friendly facilities,and emotional connections to place.

关键词： Daycare center Environmental space Willingness to demand design optimization

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Estimates of net primary productivity and actual evapotranspiration over the Tibetan Plateau from the Community Land Model version 4.5 with four atmospheric forcing datasets

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Journal of Plant Ecology 2024年第4期17卷 70-89页

作者： Shan Lin Kewei Huang Xiangyang Sun Chunlin Song Juying Sun Shouqin Sun Genxu Wang Zhaoyong Hu State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China Hubei Key Laboratory of Basin Water Security Changjiang SurveyPlanningDesign and Research Co.Ltd.Wuhan 430010China Research Unit Forest Dynamics Swiss Federal Research Institute for ForestSnow and Landscape Research WSLBirmensdorf 8903Switzerland

The accuracy of the simulation of carbon and water processes largely relies on the selection of atmospheric forcing datasets when driving land surface models(LSM).Particularly in high-altitude regions,choosing appropriate atmospheric forcing datasets can effectively reduce uncertainties in the LSM ***,this study conducted four offline LSM simulations over the Tibetan Plateau(TP)using the Community Land Model version 4.5(CLM4.5)driven by four state-of-the-art atmospheric forcing *** performances of CRUNCEP(CLM4.5 model default)and three other reanalysis-based atmospheric forcing datasets(***,GSWP3 and WFDEI)in simulating the net primary productivity(NPP)and actual evapotranspiration(ET)were evaluated based on in situ and gridded reference *** with in situ observations,simulated results exhibited determination coefficients(R2)ranging from 0.58 to 0.84 and 0.59 to 0.87 for observed NPP and ET,respectively,among which GSWP3 and ITPCAS showed superior *** the plateau level,CRUNCEP-based simulations displayed the largest bias compared with the reference NPP and ***3-based simulations demonstrated the best performance when comprehensively considering both the magnitudes and change trends of TP-averaged NPP and *** simulated ET increase over the TP during 1982-2010 based on ITPCAS was significantly greater than in the other three simulations and reference ET,suggesting that ITPCAS may not be appropriate for studying long-term ET changes over the *** results suggest that GSWP3 is recommended for driving CLM4.5 in conducting long-term carbon and water processes simulations over the *** study contributes to enhancing the accuracy of LSM in water-carbon simulations over alpine regions.

关键词： land surface model carbon cycle water cycle high altitude Community Land Model version 4.5

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Metal-Organic Framework Enabling Poly(Vinylidene Fluoride)-Based Polymer Electrolyte for Dendrite-Free and Long-Lifespan Sodium Metal Batteries

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Energy & Environmental Materials 2024年第1期7卷 68-76页

作者： Yusi Lei Liang Yue Yuruo Qi Yubin Niu Shujuan Bao Jie Song Maowen Xu Faculty of Materials and Energy Institute for Clean Energy&Advanced MaterialsSouthwest UniversityChongqing 400715China Shandong Zero-One-Four Advanced Materials Co. Ltd.Feicheng 271099China

Sodium dentrite formed by uneven plating/stripping can reduce the utilization of active sodium with poor cyclic stability and,more importantly,cause internal short circuit and lead to thermal runaway and ***,sodium dendrites and their related problems seriously hinder the practical application of sodium metal batteries(SMBs).Herein,a design concept for the incorporation of metal-organic framework(MOF)in polymer matrix(polyvinylidene fluoride-hexafluoropropylene)is practiced to prepare a novel gel polymer electrolyte(PH@MOF polymer-based electrolyte[GPE])and thus to achieve high-performance *** addition of the MOF particles can not only reduce the movement hindrance of polymer chains to promote the transfer of Na^(+)but also anchor anions by virtue of their negative charge to reduce polarization during electrochemical reaction.A stable cycling performance with tiny overpotential for over 800 h at a current density of 5 mA cm^(-2)with areal capacity of 5 mA h cm^(-2)is achieved by symmetric cells based on the resulted GPE while the Na_(3)V_(2)O_(2)(PO_(4))_(2)F@rGO(NVOPF)|PH@MOF|Nacell also displays impressive specific cycling capacity(113.3 mA h g^(-1)at 1 C)and rate capability with considerable capacity retention.

关键词： dendrite-free gel polymer electrolyte metal organic framework sodium batteries

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Higher-order properties and extensions for indirect MRAC and APPC of linear systems

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Science China(Information Sciences) 2024年第4期67卷 218-238页

作者： Yanjun ZHANG Zhipeng ZHANG Jian SUN Lei WANG Kangkang ZHANG National Key Lab of Autonomous Intelligent Unmanned Systems Beijing Institute of Technology Beijing institute of Technology chongqing Innovation Center College of Control Science and Engineering Zhejiang University Department of Electrical and Electronic Engineering Imperial College London KIOS Research and Innovation Center of Excellence University of Cyprus

Recently, a reference derived some new higher-order output tracking properties for direct model reference adaptive control(MRAC) of linear time-invariant(LTI) systems: limt→∞ e~((i))(t) = 0, i = 1,..., n~*-1, where n~* and e~((i))(t) denote the relative degree of the system and the i-th derivative of the output tracking error, respectively. However, a naturally arising question involves whether indirect adaptive control(including indirect MRAC and indirect adaptive pole placement control) of LTI systems still has higher-order tracking properties. Such properties have not been reported in the literature. Therefore, this paper provides an affirmative answer to this question. Such higher-order tracking properties are new discoveries since they hold without any additional design conditions and, in particular, without the persistent excitation condition. Given the higher-order properties, a new adaptive control system is developed with stronger tracking features.(1) It can track a reference signal with any order derivatives being unknown.(2) It has higher-order exponential or practical output tracking properties.(3) Finally, it is different from the usual MRAC system, whose reference signal’s derivatives up to the n~* order are assumed to be known. Finally, two simulation examples are provided to verify the theoretical results obtained in this paper.

关键词： higher-order tracking indirect adaptive control model reference adaptive control adaptive pole placement control

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Quasi-two-dimensional strong liquid-like dynamics of surface atoms in metallic glasses

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 102-109页

作者： Bing Wang Xuanqiao Gao Rui Su Pengfei Guan School of Physical Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Innovation Center NPU chongqing Northwestern Polytechnical UniversityChongqing 401135China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China Northwest institute for Nonferrous Metal Research Xi'an 710016China institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi University Hangzhou 310018China Beijing Computational Science Research Center Beijing 100093China

The fast dynamic properties of the surface of metallic glasses(MGs) play a critical role in determining their potential applications. However, due to the significant difference in thermal history between atomic simulation models and laboratory-made samples, the atomic-scale behaviors of the fast surface dynamics of MGs in experiments remain uncertain. Herein, we prepared model MG films with notable variations in thermal stability using a recently developed efficient annealing protocol, and investigated their atomic-scale dynamics systematically. We found that the dynamics of surface atoms remain invariant, whereas the difference in dynamical heterogeneity between surface and interior regions increases with the improvement of thermal stability. This can be associated with the more pronounced correlation between atomic activation energy spectra and depth from the surface in samples with higher thermal stability. In addition, dynamic anisotropy appears for surface atoms, and their transverse dynamics are faster than normal components, which can also be interpreted by activation energy spectra. Our results reveal the presence of strong liquid-like atomic dynamics confined to the surface of laboratory-made MGs, illuminating the underlying mechanisms for surface engineering design, such as cold joining by ultrasonic vibrations and superlattice growth.

关键词： metallic glasses thermal stability invariant surface dynamics potential energy landscape dynamic anisotropy and heterogeneity

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design,preparation,microstructure and mechanical property of the lightweight radiation-shielding Mg-Ta-Al composites basing differential temperature hot rolling

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Journal of Magnesium and Alloys 2024年第6期12卷 2433-2446页

作者： Wenbo Luo Songya Feng Xiuzhu Han Li Zhou Qinke Kong Zhiyong Xue Jianzhao Wang Mei Zhan Xianhua Chen Fusheng Pan institute for Advanced Materials North China Electric Power UniversityBeijing 102206China Beijing institute of Spacecraft System Engineering Beijing 100094China Sinosteel Equipment&Engineering Co Ltd.Beijing100080China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Inner Mongolia 014030China School of Materials Science Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China

A novel lightweight,radiation-shielding Mg-Ta-Al layered metal-matrix composite(LMC)was successful designed by doping the extremely refractory metal(Ta)into Mg *** Mg-based LMCs sheets shows excellent radiation-dose shield effect,about 145 krad·a^(−1),which is about 17 times of traditional Mg alloy,while its surface density is only about 0.9 g·cm^(−2),reducing by 60%than that of pure *** quantitate relationship between radiation-dose and the materials’thickness was also confirmed to the logistic function when the surface density is in the range of 0.6-1.5 g·cm^(−2).Meantime,the rolling parameters,interface microstructure and mechanical properties in both as-rolled and annealing treated samples were *** sheets possess a special dissimilar atoms diffusion transitional zone containing an obvious inter-diffusion Mg-Al interface and the unique micro-corrugated Ta-Al interface,as well as a thin Al film with a thickness of about 10μ*** special zone could reduce the stress concentration and enhance the strength of Mg-Ta-Al *** interface bonding strength reaches up to 54-76 *** ultimate tensile strength(UTS)and yield strength(TYS)of the Mg-Ta-Al sheet were high to 413 MPa and 263 MPa,respectively,along with an elongation of 5.8%.The molecular dynamics(MD)analysis results show that the two interfaces exhibit different formation mechanism,the Mg-Al interface primarily depended on Mg/Al atoms diffusion basing point defects movement,while the Ta-Al interface with a micro-interlock pining shape formed by close-packed planes slipping during high temperature strain-induced deformation process.

关键词： Dissimilar metals composites Mg based alloys Radiation shielding Hot rolling Lightweight

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