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Sn-doped cobalt containing perovskite as the air electrode for highly active and durable reversible protonic ceramic electrochemical cells

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Journal of Advanced Ceramics 2024年第1期13卷 63-72页

作者： Min Fu Wenjing Hu Hua Tong Xin Ling Linggui Tan Fanglin Chen Zetian Tao School of Resources Environment and Safety EngineeringUniversity of South ChinaHengyang 421001China department of Mechanical engineering University of South CarolinaColumbia 29208USA

One potential solution to the problems of energy storage and conversion is the use of reversible protonic ceramic electrochemical cells(R-PCEC),which are based on the solid oxide fuel cell(SOFC)technology and offer a flexible route to the generation of renewable ***,the R-PCEC development faces a range of significant challenges,including slow oxygen reaction kinetics,inadequate durability,and poor round-trip efficiency resulting from the inadequacy of an air *** address these issues,we report novel B-sites doped Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.3)O_(3−δ)(PBCF)with varying amounts of Sn as the air electrode for R-PCEC to further enhance electrochemical performance at lower *** 600℃,R-PCEC with an air electrode consisting of Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.25)Sn_(0.05)O_(3+δ)has achieved peak power density of 1.12 W∙cm^(−2) in the fuel cell mode and current density of 1.79 A∙cm^(−2) in the electrolysis mode at a voltage of 1.3 ***,R-PCECs have shown good stability in the electrolysis mode of 100 *** study presents a practical method for developing durable high-performance air electrodes for R-PCECs.

关键词： triple conducting oxide dual-element doping protonic ceramic electrochemical cells(PCECs) catalytic

The action mechanism of the work done by the electric field force on moving charges to stimulate the emergence of carrier generation/recombination in a PN junction

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1001-1014页

作者： Lingyun GUO Yizhan YANG Wanli YANG Yuantai HU department of Mechanics School of Aerospace EngineeringHubei Key Laboratory of Engineering Structural Analysis and Safety AssessmentHuazhong University of Science and TechnologyWuhan 430074China

It is discovered that the product of the current and the electric field in a PN junction should be regarded as the rate of work(power)done by the electric field force on moving charges(hole current and electron current),which was previously misinterpreted as solely a Joule heating *** clarify that it is exactly the work done by the electric field force on the moving charges to stimulate the emergence of non-equilibrium carriers,which triggers the novel physical *** regards to Joule heat,we point out that it should be calculated from Ohm’s law,rather than simply from the product of the current and the electric *** on this understanding,we conduct thorough discussion on the role of the electric field force in the process of carrier recombination and carrier *** thermal effects of carrier recombination and carrier generation followed are incorporated into the thermal equation of *** present study shows that the exothermic effect of carrier recombination leads to a temperature rise at the PN interface,while the endothermic effect of carrier generation causes a temperature reduction at the *** two opposite effects cause opposite heat flow directions in the PN junction under forward and backward bias voltages,highlighting the significance of managing device heating phenomena in design ***,this study possesses referential significance for the design and tuning on the performance of piezotronic devices.

关键词： piezoelectric semiconductor(PS) work done by electric field force thermal effect piezotronic device resistivity conductivity

Pedestrian lane formation with following–overtaking model and measurement of system order

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Chinese Physics B 2024年第2期33卷 247-263页

作者：李碧璐李政周睿申世飞 department of engineering Physics Tsinghua UniversityBeijing 100084China School of safety Science Tsinghua UniversityBeijing 100084China

Pedestrian self-organizing movement plays a significant role in evacuation studies and architectural *** formation,a typical self-organizing phenomenon,helps pedestrian system to become more orderly,the majority of following behavior model and overtaking behavior model are imprecise and unrealistic compared with pedestrian movement in the real *** this study,a pedestrian dynamic model considering detailed modelling of the following behavior and overtaking behavior is constructed,and a method of measuring the lane formation and pedestrian system order based on information entropy is *** and analysis demonstrate that the following and avoidance behaviors are important factors of lane formation.A high tendency of following results in good lane *** non-selective following behavior and aggressive overtaking behavior cause the system order to *** most orderly following strategy for a pedestrian is to overtake the former pedestrian whose speed is lower than approximately 70%of his *** influence of the obstacle layout on pedestrian lane and egress efficiency is also studied with this *** presence of a small obstacle does not obstruct the walking of pedestrians;in contrast,it may help to improve the egress efficiency by guiding the pedestrian flow and mitigating the reduction of pedestrian system orderliness.

关键词： pedestrian movement lane formation information entropy order degree

Directly predicting N2 electroreduction reaction free energy using interpretable machine learning with non-DFT calculated features

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Journal of Energy Chemistry 2024年第10期97卷 139-148页

作者： Yaqin Zhang Yuhang Wang Ninggui Ma Jun Fan department of Materials Science and engineering City University of Hong Kong Center for Advanced Nuclear safety and Sustainable Development City University of Hong Kong department of Mechanical engineering City University of Hong Kong

Electrocatalytic nitrogen reduction to ammonia has garnered significant attention with the blooming of single-atom catalysts（SACs）,showcasing their potential for sustainable and energy-efficient ammonia ***,cost-effectively designing and screening efficient electrocatalysts remains a *** this study,we have successfully established interpretable machine learning（ML） models to evaluate the catalytic activity of SACs by directly and accurately predicting reaction Gibbs free *** models were trained using non-density functional theory（DFT） calculated features from a dataset comprising 90 graphene-supported *** results underscore the superior prediction accuracy of the gradient boosting regression（GBR） model for both Δg（N2→NNH） and ΔG（NH2→NH3）,boasting coefficient of determination（R2） score of 0.972 and 0.984,along with root mean square error（RMSE） of 0.051 and 0.085 eV,***,feature importance analysis elucidates that the high accuracy of GBR model stems from its adept capture of characteristics pertinent to the active center and coordination environment,unveilling the significance of elementary descriptors,with the colvalent radius playing a dominant ***,Shapley additive explanations（SHAP） analysis provides global and local interpretation of the working mechanism of the GBR *** analysis identifies that a pyrrole-type coordination（flag=0）,d-orbitals with a moderate occupation（Nd=5）,and a moderate difference in covalent radius(rTM-avenear 140 pm) are conducive to achieving high ***,we extend the prediction of activity to more catalysts without additional DFT calculations,validating the reliability of our feature engineering,model training,and design *** findings not only highlight new opportunity for accelerating catalyst design using non-DFT calculated features,but also shed light on the working mechanism of "black box" ML ***,the model provides valuable guidanc

关键词： Graphene Interpretable machine learning Nitrogen reduction Non-DFT features Single-atom catalyst

Superior and safer lithium sulfur batteries realized by robust polysulfides-retarding dam with high flame retardance

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Journal of Energy Chemistry 2024年第2期89卷 471-486,I0011页

作者： Junling Wang Yanfang Cao Zhirong Wang Yinquan Zhao Chuang He Fudong Zhao Chaoling Han Shui Yu Jiangsu Key Laboratory of Hazardous Chemicals safety and Control College of Safety Science and EngineeringNanjing Tech UniversityNanjing 211816JiangsuChina department of Architecture and Civil engineering City University of Hong KongHong Kong 999077China School of Mechanical and Power engineering Nanjing Tech UniversityNanjing 211816JiangsuChina

The unparalleled energy density has granted lithium-sulfur batteries(LSBs)with attractive ***,LSBs still face some unsurpassed challenges in industrialization,with polysulfides shuttling,dendrite growth and thermal hazard as the major problems triggering the cycling instability and low *** the merit of convenience,the method of designing functional separator has been ***,the carbon aerogel confined with CoS_(2)(CoS_(2)-NCA)is constructed and coated on Celgard separator surface,acquiring CoS_(2)-NCA modified separator(CoS_(2)-NCA@C),which holds the promoted electrolyte affinity and flame *** revealed,CoS_(2)-NCA@C cell gives a high discharge capacity 1536.9 mAh/g at 1st cycle,much higher than that of Celgard cell(987.1 mAh/g).Moreover,the thermal runaway triggering time is dramatically prolonged by 777.4 min,corroborating the promoted thermal safety of ***,the higher coulombic efficiency stability and lower overpotential jointly confirm the efficacy of CoS_(2)-NCA@C in suppressing the lithium dendrite ***,this work can provide useful inspirations for designing functional separator,coping with the vexing issues of LSBs.

关键词： Lithium-sulfur batteries Thermal safety Flame retardancy Separator

Acoustic emission characteristics of damage evolution of multi-scale fiber reinforced rubberized concrete under uniaxial compression and tension after being subjected to high temperatures

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Frontiers of Structural and Civil engineering 2024年第8期18卷 1237-1266页

作者： Shaoqi ZHANG Yao ZHANG Qianru LEI Yumeng YANG Yichao WANG Fei XU Zhiguo YAN Hehua ZHU Laboratory of Fire safety School of Safety Engineering and Emergency ManagementShijiazhuang Tiedao UniversityShijiazhuang 050043China Structural Health Monitoring and Control Key Laboratory of Hebei Province Shijiazhuang Tiedao UniversityShijiazhuang 050043China department of Geotechnical engineering Tongji UniversityShanghai 200092China

Recently developed multi-scale fiber(i.e.,CaCO3 whisker,polyvinyl alcohol(PVA)fiber,and steel fiber)reinforced rubberized concrete exhibits excellent mechanical properties and spalling resistance at high *** of macro properties such as strength and Young’s modulus cannot reveal and characterize damage mechanisms,particularly those relating to the multi-scale fiber strengthening *** this study,acoustic emission(AE)technology is applied to investigate the impact of multi-scale fiber on the damage evolution of rubberized concrete exposed to high temperatures,under the uniaxial compression and tension loading *** mechanical properties,AE event location,peak frequency,b-value,the ratio of rise time to amplitude(RA),average frequency(AF)values,and AE energy of specimens are *** results show that the number of events observed using AE gradually increases as the loading *** crumb rubber and fibers inhibit the generation and development of the *** is concluded that both the peak frequency and b-value reflect the extension process of *** the cracks develop from the micro scale to the macro scale,the peak frequency tends to be distributed in a lower frequency range,and the b-value decreases *** the peak stress point,the AE energy increases rapidly and the b-value *** specimens without multi-scale fibers exhibit brittle failure,while the specimens with fibers exhibit ductile *** addition,adding multi-scale fibers and crumb rubber increases the peak frequency in the medium and high frequency ranges,indicating a positive effect on inhibiting crack *** being subjected to high temperatures,the maximum and minimum b-values decrease,reflecting an increase in the number of initial cracks due to thermal ***,the RA and AF values are used to classify tensile and shear *** specimens fracture with more shear cracks under compression,and there are more tensile

关键词： multi-scale fibers acoustic emission fracture damage evolution rubberized concrete

Lunar In Situ Large-Scale Construction:Quantitative Evaluation of Regolith Solidification Techniques

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engineering 2024年第8期39卷 204-221页

作者： Charun Bao Daobo Zhang Qinyu Wang Yifei Cui Peng Feng MOE Key Laboratory of Civil engineering safety and Durability Department of Civil EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory of Hydroscience and engineering Tsinghua UniversityBeijing 100084China

Lunar habitat construction is crucial for successful lunar exploration *** to the limitations of transportation conditions,extensive global research has been conducted on lunar in situ material processing techniques in recent *** aim of this paper is to provide a comprehensive review,precise classification,and quantitative evaluation of these approaches,focusing specifically on four main approaches:reaction solidification(RS),sintering/melting(SM),bonding solidification(BS),and confinement formation(CF).Eight key indicators have been identified for the construction of low-cost and highperformance systems to assess the feasibility of these methods:in situ material ratio,curing temperature,curing time,implementation conditions,compressive strength,tensile strength,curing dimensions,and environmental *** scoring thresholds are determined by comparing the construction requirements with the actual *** the evaluated methods,regolith bagging has emerged as a promising option due to its high in situ material ratio,low time requirement,lack of hightemperature requirements,and minimal shortcomings,with only the compressive strength falling below the neutral *** compressive strength still maintains a value of 2–3 *** proposed construction scheme utilizing regolith bags offers numerous advantages,including rapid and large-scale construction,ensured tensile strength,and reduced reliance on equipment and *** this study,guidelines for evaluating regolith solidification techniques are provided,and directions for improvement are *** proposed lunar habitat design based on regolith bags is a practical reference for future research.

关键词： Lunar habitats Lunar in situ construction Regolith bag Solidification and formation In situ materials Evaluation method

Fundamentals and progress of the manifold method based on independent covers

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Science China(Technological Sciences) 2024年第4期67卷 966-991页

作者： SU HaiDong LIN ShaoZhong XIE ZhiQiang GONG YaQi QI YongFeng Material and engineering Structure department Yangtze River Scientific Research InstituteWuhan 430010China Research Center of Water engineering safety and Disaster Prevention of Ministry of Water Resources Wuhan 430010China

Aiming to solve mesh generation,computational stability,accuracy control,and other problems encountered with existing numerical methods,such as the finite element method and the finite volume method,a new numerical computational method for continuum mechanics,namely the manifold method based on independent covers(MMIC),is proposed based on the concept of mathematical manifolds,to form partitioned series solutions of partial differential *** partitions,the cover meshes have the characteristics of arbitrary shape,arbitrary connection,and arbitrary *** are expected to fundamentally solve the mesh generation problem and can also simulate the precise geometric boundaries of the CAD model and strictly impose boundary *** the selection of series solutions,local analytical solutions(such as series solutions at crack tips and series solutions in infinite domains)or proper forms of complete series can be used to reflect the local or global characteristics of the physical field to accelerate *** applications are presented.A new method of beam,plate,and shell analysis is *** deformation characteristics of beams,plates,and shells are simulated with polynomial series of suitable forms,and the analysis of curved beams and shells with accurate geometric representation is *** the static elastic analysis of two-dimensional structures,a mesh splitting algorithm is proposed,and h-p version adaptive analysis is carried out with error ***,automatic computation integrated with CAD is *** analysis is also attempted for the solution of differential equations of *** the one-dimensional convection-diffusion equation and Burgers equation,calculation results with high precision are obtained in strong convection and shock wave simulations,avoiding nonphysical *** solving the two-dimensional incompressible Navier-Stokes equation is also *** series solution formula is used to o

关键词： series solutions mesh generation adaptive analysis fixed meshes numerical manifold method

An extended social force model on unidirectional flow considering psychological and behavioral impacts of hazard source

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Chinese Physics B 2024年第2期33卷 567-576页

作者：邓凯丰李梦胡祥敏陈涛 Institute of Public safety Research Department of Engineering PhysicsTsinghua UniversityBeijing 100084China Anhui Province Key Laboratory of Human safety Hefei 230601China Beijing Key Laboratory of Comprehensive Emergency Response Science Beijing 100084China

An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street *** sources not only physically but psychologically affect the pedestrians,which may further alter their behavioral *** effect is especially significant in narrow spaces,such as corridors and *** study aims to integrate a non-spreading hazard source into the social force model following the results from a previous experiment and simulation,and to simulate unidirectional pedestrian flows over various crowd densities and clarity–intensity properties of the hazard *** integration include a virtual repulsion force from the hazard source and a decay on the social force *** simulations reveal(i)that the hazard source creates virtual bottlenecks that suppress the flow,(ii)that the inter-pedestrian push forms a stabilisation phase on the flow-density curve within medium-to-high densities,and(iii)that the pedestrians are prone to a less orderly and stable pattern of movement in low clarity–intensity scenarios,possibly with lateral collisions passing the hazard source.

关键词： evacuation social force model hazard source unidirectional pedestrian flow