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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 m.lin 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

CFD-DEm simulation of high density particles fluidization behaviors in 3D conical spouted beds

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Particuology 2024年第5期88卷 266-281页

作者： lin Jiang mofan Qiu Rongzheng liu Bing liu Youlin Shao m.lin liu Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing 100084China

The spouted bed has been used in the coating process of high-density nuclear fuel *** particle fluidization behaviors in pseudo-2D and 3D spouted beds were simulated and *** effects of four independent variables(cone angle,particle density,inlet gas velocity,and particle loading)on particle fluidization behaviors in the 3D spouted bed were investigated *** cone angle effect on fluidization mechanism was studied quantitatively first time.A new fluidization quality index was proposed based on the particle entrainment principle,and an extreme value was obtained when the cone angle was 60°,considered to be the optimum value for the 3D conical spouted *** was indicated the gas–solid contact efficiency can be kept up if the gas velocity was proportional to ρ_(p)^(0.65) and N_(p)^(0.78) when the particle density or loading was *** results will be useful for geometry and operation parameters design of the 3D conical spouted bed and helpful for developing the fluidization mechanism of high-density particles.

关键词： Spouted bed High-density particle CFD-DEm Fluidization quality index Particle loading

Identification of the Worst-case Static Voltage Stability margin Interval of AC/DC Power System Considering Uncertainty of Renewables

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 974-987页

作者： Wanbin liu Shunjiang lin Yuerong Yang mingbo liu Qifeng Li School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China Guangdong Key Laboratory of Clean Energy Technology South China University of TechnologyGuangzhou 511458China Department of Electrical and Computer Engineering University of Central FloridaOrlandoFL 32816USA CSEE IEEE

Calculation of static voltage stability margin(SVSm)of AC/DC power systems with lots of renewable energy sources(RESs)integration requires consideration of uncertain load growth and renewable energy generation *** paper presents a bi-level optimal power flow(BLOPF)model to identify the worst-case SVSm of an AC/DC power system with line commutation converter-based HVDC and multi-terminal voltage sourced converter-based HVDC transmission *** of uncertain load growth’s hypercone model and control mode switching of DC converter stations are considered in the BLOPF ***,uncertain RES output fluctuations are described as intervals,and two three-level optimal power flow(TLOPF)models are established to identify interval bounds of the system worst-case *** two TLOPF models are both transformed into max–min bi-level optimization models according to independent characteristics of different uncertain ***,transforming the inner level model into its dual form,max–min BLOPF models are simplified to single-level optimization models for direct *** results on the modified IEEE-39 bus AC/DC case and an actual large-scale AC/DC case in China indicate correctness and efficiency of the proposed identification method.

关键词： AC/DC power system control mode switching convex relaxation dual programming multi-level optimization optimal power flow static voltage stability margin

Not in Control,but Liable?Attributing Human Responsibility for Fully Automated Vehicle Accidents

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Engineering 2024年第2期33卷 121-132页

作者： Siming Zhai lin Wang Peng liu Center for Psychological Sciences Zhejiang UniversityHangzhou 310063China Department of Library and Information Science Incheon National UniversityIncheon 22012Republic of Korea

Human agency has become increasingly limited in complex systems with increasingly automated decision-making *** instance,human occupants are passengers and do not have direct vehicle control in fully automated cars(i.e.,driverless cars).An interesting question is whether users are responsible for the accidents of these *** ethical and legal analyses frequently argue that individuals should not bear responsibility for harm beyond their ***,we consider human judgment of responsibility for accidents involving fully automated cars through three studies with seven experiments(N=2668).We compared the responsibility attributed to the occupants in three conditions:an owner in his private fully automated car,a passenger in a driverless robotaxi,and a passenger in a conventional taxi,where none of these three occupants have direct vehicle control over the involved vehicles that cause identical pedestrian *** contrast to normative analyses,we show that the occupants of driverless cars(private cars and robotaxis)are attributed more responsibility than conventional taxi *** dilemma is robust across different contexts(e.g.,participants from China vs the Republic of Korea,participants with first-vs third-person perspectives,and occupant presence vs absence).Furthermore,we observe that this is not due to the perception that these occupants have greater control over driving but because they are more expected to foresee the potential consequences of using driverless *** findings suggest that when driverless vehicles(private cars and taxis)cause harm,their users may face more social pressure,which public discourse and legal regulations should manage appropriately.

关键词： Fully automated vehicle accidents Responsibility attribution Controllability Foreseeability

Effect of hot isostatic pressure on the microstructure and tensile properties of γ'-strengthened superalloy fabricated through induction-assisted directed energy deposition

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International Journal of minerals,metallurgy and materials 2024年第5期31卷 1089-1097页

作者： Jianjun Xu Hanlin Ding Xin lin Feng liu Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 mPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core *** HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly *** further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained *** comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ ***,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.

关键词： directed energy deposition Ni-based superalloys high-temperature preheating hot isostatic pressing microstructure tensile properties

method for triangular fuzzy multiple attribute decision making based on two-dimensional density operator method

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Journal of Systems Engineering and Electronics 2024年第1期35卷 178-185页

作者： lin Youliang LI Wu liu Gang HUANG Dong School of Economics and management Hunan Institute of Science and TechnologyYueyang 414000China Hunan Vocational College for Nationalities Yueyang 414000China School of Information Science and Engineering Hunan Institute of Science and TechnologyYueyang 414000China

Aiming at the triangular fuzzy(TF)multi-attribute decision making(mADm)problem with a preference for the distribution density of attribute(DDA),a decision making method with TF number two-dimensional density(TFTD)operator is proposed based on the density operator theory for the decision maker(Dm).Firstly,a simple TF vector clustering method is proposed,which considers the feature of TF number and the geometric distance of ***,the least deviation sum of squares method is used in the program model to obtain the density weight ***,two TFTD operators are defined,and the mADm method based on the TFTD operator is ***,a numerical example is given to illustrate the superiority of this method,which can not only solve the TF mADm problem with a preference for the DDA but also help the Dm make an overall comparison.

关键词： fuzzy decision making clustering density operator multi-attribute decision making(mADm)

NFXL1 functions as a transcriptional activator required for thermotolerance at reproductive stage in Arabidopsis

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Journal of Integrative Plant Biology 2024年第1期66卷 54-65页

作者： Qiao‐Yun Zhu lin‐lin Zhang Jian‐Xiang liu State Key Laboratory of Plant Environmental Resilience College of Life SciencesZhejiang UniversityHangzhou 310027China

Plants are highly susceptible to abiotic stresses,particularly heat stress during the reproductive ***,the specific molecular mechanisms underlying this sensitivity remain largely *** the current study,we demonstrate that the Nuclear Transcription Factor,X-box Binding Protein 1-Like 1(NFXL1),directly regulates the expression of DEHYDRATION-RESPONSIVE ELEmENT-BINDING PROTEIN 2A(DREB2A),which is crucial for reproductive thermotolerance in ***1 is upregulated by heat stress,and its mutation leads to a reduction in silique length(seed number)under heat stress ***-Seq analysis reveals that NFXL1 has a global impact on the expression of heat stress responsive genes,including DREB2A,Heat Shock Factor A3(HSFA3)and Heat Shock Protein 17.6(HSP17.6)in flower ***,NFXL1 is enriched in the promoter region of DREB2A,but not of either HSFA3 or *** experiments using electrophoretic mobility shift assay have confirmed that NFXL1 directly binds to the DNA fragment derived from the DREB2A ***,effector-reporter assays have shown that NFXL1 activates the DREB2A *** DREB2A mutants are also heat stress sensitive at the reproductive stage,and DEREB2A is epistatic to NFXL1 in regulating thermotolerance in flower *** is known that HSFA3,a direct target of DREB2A,regulates the expression of heat shock proteins genes under heat stress ***,our findings establish NFXL1 as a critical upstream regulator of DREB2A in the transcriptional cassette responsible for heat stress responses required for reproductive thermotolerance in Arabidopsis.

关键词： Arabidopsis DREB2A heat stress NFXL1 reproductive thermotolerance

Improved catalytic performance of CO_(2) electrochemical reduction reaction towards ethanol on chlorine-modified Cu-based electrocatalyst

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Nano Research 2024年第5期17卷 3761-3768页

作者： Yifan liu Hehua Tang Yitian Zhou Bo-lin lin School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

Effective electrochemical conversion of CO_(2) to value-added liquid multi-carbon products driven by renewable energy is a promising approach to alleviate excessive CO_(2) emission and achieve large-scale renewable energy ***,the selectivity and catalytic activity towards liquid multi-carbon products of CO_(2) electroreduction reaction are still unsatisfactory due to the sluggish C-C coupling process and the formation of complex oxygen-containing ***,designing and fabricating highly effective electrocatalysts is crucial for practical applications in this ***,we developed Cl-modified Cu catalyst(Cu-Cl)for efficient electrochemical reduction of CO_(2) to *** optimal Faradaic efficiency and partial current density of ethanol on the Cu-Cl sample reached 26.2%and 343.2 mA·cm^(-2) at-0.74 V(*** hydrogen electrode(RHE)),which were 1.66 and 1.76 times higher than those of the catalyst without Cl decoration,outperforming those in most previously reported *** functional theory(DFT)calculations revealed that the Cl-modified Cu surface suppressed the parasitic hydrogen evolution reaction(HER)and reduced the energy barrier for the C-C coupling process,making the formation of key intermediates favorable for ethanol ***,the decoration of Cl on the Cu surface facilitated ethanol formation.

关键词： CO_(2)electrochemical reduction halogen chlorine Cu-based catalysts ethanol multi-carbon products

Digital twin system framework and information model for industry chain based on industrial Internet

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Frontiers of Information Technology & Electronic Engineering 2024年第7期25卷 951-967页

作者： Wenxuan WANG Yongqin liu Xudong CHAI lin ZHANG School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Department of Control Science and Engineering Jilin UniversityChangchun 130012China CASICloud China Aerospace Science and Industry Corporation LimitedBeijing 100080China

The integration of industrial Internet,cloud computing,and big data technology is changing the business and management mode of the industry ***,the industry chain is characterized by a wide range of fields,complex environment,and many factors,which creates a challenge for efficient integration and leveraging of industrial big *** at the integration of physical space and virtual space of the current industry chain,we propose an industry chain digital twin(DT)system framework for the industrial *** addition,an industry chain information model based on a knowledge graph(KG)is proposed to integrate complex and heterogeneous industry chain data and extract industrial ***,the ontology of the industry chain is established,and an entity alignment method based on scientific and technological achievements is ***,the bidirectional encoder representations from Transformers(BERT)based multi-head selection model is proposed for joint entity–relation extraction of industry chain ***,a relation completion model based on a relational graph convolutional network(R-GCN)and a graph sample and aggregate network(GraphSAGE)is proposed which considers both semantic information and graph structure information of *** results show that the performances of the proposed joint entity–relation extraction model and relation completion model are significantly better than those of the ***,an industry chain information model is established based on the data of 18 industry chains in the field of basic machinery,which proves the feasibility of the proposed method.

关键词： Industry chain Digital twin Industrial Internet Knowledge graph Graph neural network