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Interplay of transport processes and interfacial chemistry affecting chromium reduction and reoxidation with iron and manganese

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Frontiers of Environmental Science & Engineering 2020年第5期14卷 55-63页

作者： Chao Pan Daniel Giammar Department of Energy Environmentaland Chemical EngineeringWashington University in St.LouisSt.LouisMO 63130USA Present affiliation:Glenn *** Institute Physical&Life SciencesLawrence Livermore National LaboratoryLivermoreCA 94550USA

Hexavalent chromium(Cr(Ⅵ))is a water-soluble pollutant in soil and groundwater,the mobility,bioavailability,and toxicity of which can be controlled by transforming to less mobile and more environmentally benign Cr(Ⅲ)by ways of reduction.This review focused on recent advances in identifying the reaction pathways,kinetics,and products of iron-based techniques for Cr(Ⅵ)removal.It also examines new information regarding remobilization of Cr(Ⅲ)in the existence of complexing ligands and manganese(Mn)of different oxidation states.A range of iron-based techniques can remove Cr(Ⅵ)from water by adsorption or reduction-coprecipitation processes.However,the success of a chromium treatment or remediation strategy requires the stability of the Cr(Ⅲ)-containing solids with respect to solubilization or reoxidation in the settings they are generated.Manganese is ubiquitous in aquatic and terrestrial environments,and the redox cycling of manganese may greatly influence the fate,transport,and distribution of chromium.Coupling of redox reactions of chromium,iron,and manganese involves reaction pathways not only in the aqueous phase but also at solid-aqueous interfaces.To provide a quantitative understanding of these processes,it is essential to develop mechanistically based kinetic and transport models.Continued research should be made on iron-based treatment of Cr(Ⅵ)-contaminated water and soils and the stability of the subsequently produced Cr(Ⅲ)-containing solids at environmentally relevant conditions,which will support improved predictions of chromium's environmental fate and transport and aid in decision-making for remediation and treatment of Cr contamination.

关键词： Chromium(Ⅵ)contamination Redox reaction Iron oxide Manganese oxide Modeling

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The SSA-BP-based potential threat prediction for aerial target considering commander emotion

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Defence Technology（防务技术） 2022年第11期18卷 2097-2106页

作者： Xun Wang Jin Liu Tao Hou Chao Pan College of Information Science and Engineering Wuhan University of Science and TechnologyWuhan430081China Beijing Xin Li Machinery Limited Liability Company Beijing100039China School of Information and Communication Engineering Hubei University of EconomicsWuhan430205China

The target's threat prediction is an essential procedure for the situation analysis in an aerial defense system.However,the traditional threat prediction methods mostly ignore the effect of commander's emotion.They only predict a target's present threat from the target's features itself,which leads to their poor ability in a complex situation.To aerial targets,this paper proposes a method for its potential threat prediction considering commander emotion(PTP-CE)that uses the Bi-directional LSTM(BiLSTM)network and the backpropagation neural network(BP)optimized by the sparrow search algorithm(SSA).Furthermore,we use the BiLSTM to predict the target's future state from real-time series data,and then adopt the SSA-BP to combine the target's state with the commander's emotion to establish a threat prediction model.Therefore,the target's potential threat level can be obtained by this threat prediction model from the predicted future state and the recognized emotion.The experimental results show that the PTP-CE is efficient for aerial target's state prediction and threat prediction,regardless of commander's emotional effect.

关键词： Aerial targets Emotional factors Potential threat prediction BiLSTM Sparrow search algorithm Neural network

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Excitation Current and Vibration Characteristics of DC Biased Transformer

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CSEE Journal of Power and Energy Systems 2021年第3期7卷 604-613页

作者： Chao Pan Chengjian Wang Hao Su Key Laboratory of Modem Power System Simulation and Control&Renewable Energy Technology Ministry of Education(Northeast Electric Power University)Jilin 132012China

In practical engineering,DC disturbance will lead to excitation saturation and vibration intensification on transformer core,as well as affecting the normal operation of equipment and power grid.According to the problem,a new idea is proposed in this paper.Based on the electromagnetic characteristics of DC biased transformer,excitation saturation and core vibration are studied by using excitation-vibration harmonic response analysis method.Excitation current is identified through electromagnetic coupling to characterize the excitation saturation degree.Then,vibration harmonic response model is established to analyze core vibration.Electromagnetic characteristics of DC biased Y/△transformer are simulated.The variation of excitation current and core vibration at different DC levels are studied.Excitation-vibration characteristics of three-phase group transformer and three-phase three-limb transformer are compared and sum-marized.With experimental platform built,the correctness of simulation results is verified by experimental data,and the effectiveness of the proposed method can be proved.

关键词： DC disturbance excitation-vibration harmonic response Y/△transformer

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Mechanism and control technology of strong ground pressure behaviour induced by high-position hard roofs in extra-thick coal seam mining

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International Journal of Mining Science and Technology 2022年第3期32卷 499-511页

作者： Chao Pan Binwei Xia Yujun Zuo Bin Yu Changnan Ou Mining College Guizhou UniversityGuiyang 550025China National&Local Joint Engineering Laboratory of Gas Drainage in Complex Coal Seam Chongqing UniversityChongqing 400044China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China

This work aimed at revealing the mechanism of strong ground pressure behaviour(SGPB)induced by high-position hard roof(HHR).Based on the supporting structures model of HHR,a modified voussoir beam mechanical model for HHR was established by considering the gangue support coefficient,through which the modified expressions of limit breaking span and breaking energy of HHR were deduced.Combined with the relationship between the dynamic-static loading stress of supporting body(hydraulic support and coal wall)and its comprehensive supporting strength,the criteria of ground pressure behaviour(GPB)induced by HHR were discussed.The types of Ⅰ_(1),Ⅰ_(2),Ⅱ_(1),andⅡ_(2) of GPB were interpreted.Results showed that types Ⅰ_(1) and Ⅰ_(2) were the main forms of SGPB in extra-thick coal seam mining.The main manifestation of SGPB was static stress,which was mainly derived from the instability of HHR rather than fracture.Accordingly,an innovative control technology was proposed,which can weaken static load by vertical-well separated fracturing HHR.The research results have been successfully applied to the 8101 working face in Tashan coal mine,Shanxi Province,China.The results of a digital borehole camera observation and stress monitoring proved the rationality of the GPB criteria.The control technology was successful,paving the way for new possibilities to HHR control for safety mining.

关键词： Extra thick coal seam High-position hard roof Strong ground pressure behaviour Supporting structures Criteria of ground pressure behaviour Controlling effects

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The historical logics and geographical patterns of rural-urban governance in China

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Journal of Geographical Sciences 2022年第7期32卷 1225-1240页

作者： YE chao pan Jiawei LIU Zhimin Key Laboratory of Geographic Information Science(Ministry of Education) School of Geographic SciencesResearch Center for China Administrative DivisionEast China Normal UniversityShanghai 200241China

The advent of a mobile society has led to profound changes in China’s traditional rural-urban pattern and called for new strategies for urban and rural governance.Based on a macro perspective of temporal and spatial evolution,this study analyzes the historical logics of rural-urban governance,explores the geographical patterns of challenges in China’s rural-urban governance,and finally puts forward targeted strategies for rural-urban governance toward integrated and sustainable development in China.From the historical perspective,the urban originates from the rural,and the connotation of rural,that is,a regional-scale outlook,rural-urban relations,and sociocultural interaction,forms the traditional approach to rural-urban governance.China’s rural-urban governance has evolved from antagonism toward integration.In terms of theoretical development,the turn toward mobility is an important driving factor shaping and promoting the transformation of research focus on rural-urban governance.The mobility of urban and rural factors has especially in recent decades brought extensive challenges for governance,which are highlighted by the disintegration of the stability of rural and urban structures,growing regional disparities in rural education levels,and serious aging and hollowing crises in rural areas.We therefore propose that rural-urban governance should give sufficient consideration to the convergence of wider interests;realize social potential through institutional,cultural and spatial restructuring;and attach importance to collaborative development and governance.And the transfer of rural problems to urban areas should be paid attention to by rural-urban governance.This research enriches the knowledge regarding the logics and patterns of China’s rural-urban governance from an interdisciplinary perspective.It is also helpful in the promotion of rural-urban integration and sustainable development,especially at a time when the mobility of social factors between rural areas and urban areas increasingly challenges tradit

关键词： rural-urban relation urbanization sustainable development mobility regional disparities

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Deep Reinforcement Learning-Based URLLC-Aware Task Offloading in Collaborative Vehicular Networks

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China Communications 2021年第7期18卷 134-146页

作者： Chao Pan Zhao Wang Zhenyu Zhou Xincheng Ren Hebei Key Laboratory of Power Internet of Things Technology North China Electric Power UniversityBeijing102206Baoding071003HebeiChina Shaanxi Key Laboratory of Intelligent Processing for Big Energy Data Yanan UniversityYanan 716000China

Collaborative vehicular networks is a key enabler to meet the stringent ultra-reliable and lowlatency communications(URLLC)requirements.A user vehicle(UV)dynamically optimizes task offloading by exploiting its collaborations with edge servers and vehicular fog servers(VFSs).However,the optimization of task offloading in highly dynamic collaborative vehicular networks faces several challenges such as URLLC guaranteeing,incomplete information,and dimensionality curse.In this paper,we first characterize URLLC in terms of queuing delay bound violation and high-order statistics of excess backlogs.Then,a Deep Reinforcement lEarning-based URLLCAware task offloading algorithM named DREAM is proposed to maximize the throughput of the UVs while satisfying the URLLC constraints in a besteffort way.Compared with existing task offloading algorithms,DREAM achieves superior performance in throughput,queuing delay,and URLLC.

关键词： collaborative vehicular networks task of-floading URLLC awareness deep Q-learning

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Three-dimensional general magneto-electro-elastic finite element model for multiphysics nonlinear analysis of layered composites

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Applied Mathematics and Mechanics(English Edition) 2023年第1期44卷 53-72页

作者： Zheng GONG Yinxiao ZHANG Ernian pan chao ZHANG School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications Xi'an 710072China Civil Engineering and Institute of Pioneer Semiconductor Innovation Yang Ming Chiao Tung UniversityHsinchu 30010TaiwanChina School of Civil Aviation Northwestern Polytechnical UniversityXi'an 710072China

In this paper,by defining a general potential energy for the multiphase coupled multiferroics and applying the minimum energy principle,the coupled governing equations are derived.This system of equations is then discretized as a general three-dimensional(3D)finite element(FE)model based on the COMSOL software.After validating the formulation,it is then applied to the analysis and design of the common sandwich structure of multiferroics composites.Under the typical static loading,the effects of general lateral boundary conditions,material grading,nonlinearity,as well as polarization orientation on the composites are analyzed.For the magneto-electro-elastic(MEE)sandwich made of piezoelectric BaTiO_(3)and magnetostrictive CoFe_(2)O_(4)with different stacking sequences,various interesting features are observed which should be very helpful for the design of high-performance multiphase composites.

关键词： multiferroics sandwich composite magneto-electro-elastic(MEE)material multilayered plate nonlinear behavior

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Development of machine learning multi-city model for municipal solid waste generation prediction

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Frontiers of Environmental Science & Engineering 2022年第9期16卷 89-98页

作者： Wenjing Lu Weizhong Huo Huwanbieke Gulina Chao Pan School of Environment Tsinghua UniversityBeijing 100084China

Integrated management of municipal solid waste(MSW)is a major environmental challenge encountered by many countries.To support waste treatment/management and national macroeconomic policy development,it is essential to develop a prediction model.With this motivation,a database of MSW generation and feature variables covering 130 cities across China is constructed.Based on the database,advanced machine learning(gradient boost regression tree)algorithm is adopted to build the waste generation prediction model,i.e.,WGMod.In the model development process,the main influencing factors on MSW generation are identified by weight analysis.The selected key influencing factors are annual precipitation,population density and annual mean temperature with the weights of 13%,11%and 10%,respectively.The WGMod shows good performance with R^(2)=0.939.Model prediction on MSW generation in Beijing and Shenzhen indicates that waste generation in Beijing would increase gradually in the next 3–5 years,while that in Shenzhen would grow rapidly in the next 3 years.The difference between the two is predominately driven by the different trends of population growth.

关键词： Municipal solid waste Machine learning Multi-cities Gradient boost regression tree

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Structural regulation of single-atomic site catalysts for enhanced electrocatalytic CO_(2)reduction

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Nano Research 2022年第6期15卷 4925-4941页

作者： Minmin Wang Min Li Yunqi Liu chao Zhang Yuan pan State Key Laboratory of Heavy Oil Processing China University of Petroleum(East China)Qingdao 266580China MOE International Joint Laboratory of Materials Microstructure Institute for New Energy Materials and Low Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China

Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)is considered an efficient way to convert CO_(2)into high-value-added chemicals,and thus is of significant social and economic value.Metal single-atomic site catalysts(SASCs)generally have excellent selectivity because of their 100%atomic utilization and uniform structure of active sites,and thus promise a broad range of applications.However,SASCs still face challenges such as low intrinsic activity and low density of active sites.Precise regulation of the microstructures of SASCs is an effective method to improve their CO_(2)RR performance and to obtain deep reduction products.In this article,we systematically summarize the current research status of SASCs developed for highly efficient catalysis of CO_(2)RR,discuss the various structural regulation methods for enhanced activity and selectivity of SASCs for CO_(2)RR,and review the application of in-situ characterization technologies in the SASC-catalyzed CO_(2)RR.We then discuss the problems yet to be solved in this area,and propose the future directions of the research on the design and application of SASCs for CO_(2)RR.

关键词： Electrocatalysis single-atomic site catalyst structure regulation active site carbon dioxide reduction reaction

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Electrochemical probing into the active sites of graphitic-layer encapsulated iron oxygen reduction reaction electrocatalysts

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Science Bulletin 2018年第1期63卷 24-30页

作者： Lijie Zhong Jens Oluf Jensen Lars Nilausen Cleemann Chao Pan Qingfeng Li Department of Energy Conversion and Storage Technical University of Denmark

The graphitic-layer encapsulated iron-containing nanoparticles(G@Fe) have been proposed as a potential type of active and stable non-precious metal electrocatalysts(NPMCs) for the oxygen reduction reaction(ORR). However, the contribution of the encapsulated components to the ORR activity is still unclear compared with the well-recognized surface coordinated FeN_x/C structure. Using the strong complexing effect of the iron component with anions, cyanide(CN^-) in alkaline and thiocyanate(SCN^-) in acidic media, the metal containing active sites are electrochemically probed. Three representative catalysts are chosen for a comparison including the as-prepared encapsulated G@Fe, commercial Fe/N/C catalyst with iron–nitrogen coordinated surface functionalities and molecular iron phthalocyanine(Fe Pc) containing well-defined structures and compositions. It was found that all samples showed significant shifts of half-wave potentials indicating that surface Fe coordinated sites in all cases. The G@Fe catalyst showed the weakest poisoning effect(the lowest shifts of half-wave potential) compared to the Fe/N/C and Fe Pc catalysts in both electrolytes. These results could be explained that the encapsulated iron components influence the FeN_x/C and/or N_xC surface functionality.

关键词：电气化学含铁地点反应探查催化剂包氧表面功能

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