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Effects of vibration conditions,spatial confinement and friction on mixing and segregation characteristics of mixed pebble beds for CFETR WCCB blank.t

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Particuology 2024年第2期85卷 268-279页

作者： Yong liu Chongyang He Cong Wang Lei Chen Songlin liu Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230027China Chengdu University Chengdu610106China Zhejiang Lab Hangzhou310000China

This paper presents the study of the dynamic characteristics of confined mixed pebble beds with different friction under different vibration conditions using the discrete element ***λsegre-gation index is used to quantify the degree of particle mixing or *** percolation,convection and diffusion mechanisms are responsible for the segregation patterns of the mixed *** results show the degree of segregation can be suppressed by decreasing the vibration acceleration or free space height below a *** simulation reveals the threshold of vibration acceleration or free space height both are related to the bed height increment which determines the strength of the percolation *** addition,the strength of percolation and convection becomes weak.r by decreasing the friction of particles and walls,which mak.s the pebbled bed remains in a mixed state under *** findings are significant to clarify the main factors behind the three segregation mechanisms and hence provide solutions to retaining the mixed state of the Li2TiO3&Be12Ti mixed pebble bed.

关键词： Vibration Segregation Binary pebble bed Discrete element method

Identification of the optimal doping position of hetero-atoms in chalcogen-doped Fe-N-C catalysts for oxygen reduction reaction

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Particuology 2024年第6期89卷 99-108页

作者： Weihao liu Huanhuan He Qingtao liu Xin Wan Jianglan Shui School of Materials Science and Engineering Beihang UniversityBeijing100191China School of Space and Environment Beihang UniversityBeijing102206China Tianmushan Laboratory Hangzhou310023China

The excellent oxygen reduction reaction(ORR)activity of Fe–N–C catalysts in acidic media mak.s them potential for low-cost proton exchange membrane fuel *** recent years,it has been shown that heteroatoms(B,O,S,P,Cl,F,etc.)can be used as electron-withdrawing groups to modulate the planar structure and electron distribution of the Fe–Nx active sites to achieve simultaneous improvement of catalytic activity and ***,the optimal location of the heteroatoms remains ***,tak.ng chalcogen heteroatoms(S and Se)as an example,we control the doping positions and investigate their effect on the ORR performance of the Fe–N–C *** first coordination shell of the iron single atom is identified as the optimal doping *** optimized catalysts Fe–N_(3)Se_(1)/NC and Fe–N_(3)Se_(1)/NC demonstrate improved activity and stability in both half cells and fuel *** work.provides insights into the enhancement mechanism of heteroatom doping in single-atom catalysts.

关键词： Oxygen reduction reaction Fe-N-C catalysts Hetero-atom doping Doping position Enhancement mechanism

High-performance,stable CoNi LDH@Ni foam composite membrane with innovative peroxymonosulfate activation for 2,4-dichlorophenol destruction

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Journal of Environmental Sciences 2024年第7期141卷 235-248页

作者： Yu liu Weibao liu Xinrui Gan Jiangwei Shang Xiuwen Cheng College of Chemistry and Environmental Science Xinjiang Laboratory of Phase Transitions and Microstructures of Condensed Matter PhysicsYili Normal UniversityYining 835000China k.y Laboratory for Environmental Pollution Prediction and Control Gansu ProvinceCollege of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China

In this study,the cobalt-nick.l layered double hydroxides(CoNi LDH)were synthesized with a variety of Co/Ni mass ratio,as *** comparison,Co1Ni3LDH presented the best peroxymonosulfate(PMS)activation efficiency for 2,4-dichlorophenol ***,CoNi LDH@Nick.l foam(CoNi LDH@NF)composite membrane was constructed for enhancing the stability of catalytic ***,CoNi LDH@NF-PMS system exerted high degradation efficiency of 99.22%within 90 min for 2,4-DCP when[PMS]_(0)=0.4 g/L,Co^(1)Ni^(3)LDH@NF=2 cm×2 cm(0.2 g/L),reaction temperature=298 *** the surface morphology and structure of the catalyst,it was demonstrated that the CoNi LDH@NF composite membrane possessed abundant cavity structure,good specific surface area and sufficient active ***,·OH,SO_(4)·^(-)and^(1)O_(2)played the primary role in the CoNi LDH@NF-PMS system for 2,4-DCP decomposition,which revealed the PMS activation mechanism in CoNi LDH@NF-PMS ***,this study eliminated the stability and adaptability of CoNi LDH@NF composite membrane,proposing a new theoretical basis of PMS heterogeneous catalysts selection.

关键词： CoNi LDH@NF composite membrane Peroxymonosulfate 2,4-dichlorophenol Reactive radicals

Unmanned Aerial Vehicles General Aerial Person-Vehicle Recognition Based on Improved YOLOv8s Algorithm

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Computers, Materials & Continua 2024年第3期78卷 3787-3803页

作者： Zhijian liu School of Electrical Engineering and Electronic Information Xihua UniversityChengdu610036China

Considering the variations in imaging sizes of the unmanned aerial vehicles(UAV)at different aerial photography heights,as well as the influence of factors such as light and weather,which can result in missed detection and false detection of the model,this paper presents a comprehensive detection model based on the improved lightweight You Only Look.Once version 8s(YOLOv8s)algorithm used in natural light and infrared scenes(L_YOLO).The algorithm proposes a special feature pyramid network.SFPN)structure and substitutes most of the neck.feature extraction module with the Special deformable convolution feature extraction module(SDCN).Moreover,the model undergoes pruning to eliminate redundant ***,the non-maximum suppression algorithm of intersection-union ratio based on minimum point distance(MPDIOU_NMS)algorithm has been integrated to eliminate redundant detection boxes,and a comprehensive validation has been conducted using the infrared aerial dataset and the Visdrone2019 *** comprehensive experimental results demonstrate that when the number of parameters and floating-point operations is reduced by 30%and 20%,respectively,there is a 1.2%increase in mean average precision at a threshold of 0.5(mAP(0.5))and a 4.8%increase in mAP(0.5:0.95)on the infrared ***,the mAP on the Visdrone2019 dataset has experienced an average increase of 12.4%.The accuracy and recall rates have seen respective increases of 9.2%and 3.6%.

关键词： YOLOv8s SPFN SDCN pruning MPDIOU_NMS

Explainable Neural Network.for Sensitivity Analysis of Lithium-ion Battery Smart Production

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IEEE/CAA Journal of Automatica Sinica 2024年第9期11卷 1944-1953页

作者： k.ilong liu Qiao Peng Yuhang liu Naxin Cui Chenghui Zhang School of Control Science and Engineering Shandong UniversityJinan 250061China Information Technology Analytics&Operations groupQueen’s University BelfastBelfast BT71NNUK

Battery production is crucial for determining the quality of electrode,which in turn affects the manufactured battery *** battery production is complicated with strongly coupled intermediate and control parameters,an efficient solution that can perform a reliable sensitivity analysis of the production terms of interest and forecast k.y battery properties in the early production phase is urgently *** paper performs detailed sensitivity analysis of k.y production terms on determining the properties of manufactured battery electrode via advanced data-driven *** be specific,an explainable neural network.named generalized additive model with structured interaction(GAM-SI)is designed to predict two k.y battery properties,including electrode mass loading and porosity,while the effects of four early production terms on manufactured batteries are explained and *** experimental results reveal that the proposed method is able to accurately predict battery electrode properties in the mixing and coating *** addition,the importance ratio rank.ng,global interpretation and local interpretation of both the main effects and pairwise interactions can be effectively visualized by the designed neural *** to the merits of interpretability,the proposed GAM-SI can help engineers gain important insights for understanding complicated production behavior,further benefitting smart battery production.

关键词： Battery management battery manufacturing data science explainable artificial intelligence sensitivity analysis

Active MoS_(2)-based electrode for green ammonia synthesis

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Chinese Journal of Chemical Engineering 2024年第1期65卷 268-275页

作者： Xin liu Lei Yang Tao Wei Shanping liu Beibei Xiao School of Energy and Power Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Institute Charles Gerhardt Montpellier UMR-5253Universite de MontpellierCNRSENSCMPlace E.Bataillon34095 Montpellier Cedex 05France

Nitrogen electro-reduction under mild conditions is one promising alternative approach of the energyconsuming Haber-Bosch process for the artificial ammonia *** critical aspect to unlock.ng this technology is to discover the catalysts with high selectivity and *** this work.the N_(2)-to-NH_(3)conversion on the functional MoS_(2)is fully investigated by density functional theory calculations since the layered MoS_(2)provides the ideal platform for the elaborating copies of the nitrogenase found in nature,wherein the functionalization is achieved via basal-adsorption,basal-substitution or edge-substitution of transition metal *** results reveal that the edge-functionalization is a feasible strategy for the activity promotion;however,the basal-adsorption and basal-substitution separately suffer from the electrochemical instability and the NRR ***,MoS_(2)functionalized via edge W-substitution exhibits an exceptional *** energetically favored reaction pathway is through the distal pathway and a limiting potential is less than 0.20 ***,this work.escalates the rational design of the high-effective catalysts for nitrogen fixation and provides the explanation why the predicated catalyst have a good performance,paving the guidance for the experiments.

关键词： Nitrogen reduction reaction Density functional theory calculations Molybdenum disulfide Electrochemistry Catalyst Thermodynamics

CFD-DEM simulation of fluorination reaction in fluidized beds with local grid and time refinement method

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Particuology 2024年第1期84卷 145-157页

作者： Mofan Qiu Lin Jiang Rongzhen liu Yaping Tang Malin liu Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing100084China

The gas-solid reaction process with wide particle size distribution is extensively used in the chemical engineering field,especially the particle reacts with the gas gradually,such as fluorination reactions in fluidized *** the computational fluid dynamics-discrete element method(CFD-DEM)is used for the coupling simulation of multiphase and polydisperse particle reaction system,the grid size directly affects the accuracy of flow field information and simulation of chemical ***,particle calculation time step will directly affect the efficiency of coupling *** this work.a local grid and time step refinement method is proposed to simulate multiphase and polydisperse particle fluid-ization reaction *** this method,the refined DEM grids are automatically generated in the computational domain around the fine particles,and the detailed fluid phase information is obtained with the interpolation *** the two-phase coupling process,particles are divided into different groups based on physical properties,each group has its own independent time *** multistage conical-cylindrical spouted bed is proposed for the fluorination reaction process;the operating gas ve-locity range of the polydisperse particle system is extended by the new design while the particle size distribution changes with the gas-solid reaction *** is demonstrated that the local grid and time step refinement method can improve the accuracy and efficiency of the traditional CFD-DEM method in the reaction process simulation,which describes a polydisperse particle system with wide particle size *** at improving the simulation accuracy and efficiency,this paper will be helpful for simulating the particle reaction process in the gas-solid fluidized bed and beneficial for the development of the CFD-DEM method.

关键词： CFD-DEM Polydisperse particle Two-phase flow Fluidized bed

Effect of Al_(2)O_(3)fiber on twin intersections-induced dynamic recrystallization in fine-grained TiAl matrix composite

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Journal of Materials Science & Technology 2024年第5期172卷 1-14页

作者： Yaofeng Luo Yan Wang Li Wang Bin liu Yong liu State k.y Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Dynamic recrystallization(DRX)is of great significance for the thermomechanical processing and microstructural regulation of TiAl ***,the underlying DRX mechanism remains poorly *** this study,an Avrami k.netics model for DRX was established,which was capable of predicting the DRX fraction *** addition,the effect of Al_(2)O_(3)short fiber on the DRX mechanisms of TiAl matrix composite during the isothermal compression was investigated for the first *** re-sults showed that other than inhibiting DRX by particles in the TiAl matrix composites,the addition of Al_(2)O_(3)short fiber accelerated a novel DRX process,which was induced by twinning and twin intersec-tions(TDRX).Thus,this composite exhibited a higher DRX rate than that of the as-cast TiAl monolithic *** origin of the twin intersection and TDRX for the composite was *** stress concentration near the Al_(2)O_(3)fiber was above the critical shear stress for twinning and thus was favorable for the formation of twinning and twin *** high stored strain energy at the regions of twins and twin intersections provided the driving force for *** accelerated the grain refinement in the TiAl matrix near the Al_(2)O_(3)*** present findings would provide a new perspective on DRX mechanisms,and provide the scientific guidance for optimizing the microstructures of TiAl matrix composites.

关键词： TiAl matrix composite Al_(2)O_(3)fiber Twin intersection Dynamic recrystallization

Impact of Carbon Chain Structures in the Back.one on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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Chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： Chi Zhang Rong liu Jing-Yuan liu Wen-Wei Jiang k.y Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS back.one to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the back.one chain structures by substituting phenyl units with alk.l chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alk.l chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alk.l chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remark.ble flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 k.which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain