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Segregation of binary particles in gas-solid fluidized bed

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Frontiers of Chemical Science and Engineering 2024年第6期18卷 113-121页

作者： Yaxiong Yu Feng Lu Xuan He Fei Wei chenxi Zhang Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China Ordos Laboratory Ordos 017010China Institute for Carbon Neutrality Tsinghua UniversityBeijing 100084China

Particle segregation and mixing behavior play a crucial role in industrial *** study investigates the saturated jetsam fraction,which indicates the maximum capacity of flotsam to entrain jetsam,in an initially separated binary fluidized bed with particle size *** to the value of saturated jetsam fraction,three distinct regimes-segregation,mixing,and an intermediate regime-are ***,intriguing relationships between the saturated jetsam fraction and superficial gas velocity are observed,exhibiting monotonic trends in both the segregation and mixing regimes,while a unique volcano-shaped curve in the intermediate ***,a comprehensive entrainment model based on two-fluid model elucidates the observed phenomena,emphasizing the significance of mixing behavior in fluidized layer on the saturated jetsam *** work offers potential insights for evaluating segregation in industrial applications.

关键词： fluidized bed segregation binary bubbles entrainment

Finite Element Simulations on Failure Behaviors of Granular Materials with Microstructures Using a Micromechanics-Based Cosserat Elastoplastic Model

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2305-2338页

作者： chenxi Xiu Xihua Chu School of Civil Engineering Chongqing Jiaotong UniversityChongqing400074China School of Civil Engineering Wuhan UniversityWuhan430072China

This paper presents a micromechanics-based Cosserat continuum model for microstructured granular *** utilizing this model,the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural *** microstructures under consideration can be classified into three categories:a medium-dense microstructure,a dense microstructure consisting of one-sized particles,and a dense microstructure consisting of two-sized ***,the Cosserat elastoplastic model,along with its finite element formulation,is derived using the extended Drucker-Prager yield *** investigate failure behaviors,numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element(UEL)*** demonstrates the capacity of the proposed model to simulate the phenomena of strain-softening and strain *** study investigates the influence of microscopic parameters,including contact stiffness parameters and characteristic length,on the failure behaviors of granularmaterials ***,the study examines themesh independence of the presented model and establishes its relationship with the characteristic length.A comparison is made between finite element simulations and discrete element simulations for a medium-dense microstructure,revealing a good agreement in results during the elastic *** parameters describing plasticity are shown to be partially related to microscopic factors such as confining pressure and size of the representative volume element.

关键词： Granular materials micromechanics Cosserat elastoplastic model microstructures failure behaviors

Seismic performance evaluation of water supply pipes installed in a full-scale RC frame structure based on a shaking table test

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 163-178页

作者： Wu Houli Guo Endong Wang Jingyi Dai Xin Dai chenxi Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin 150080China

As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much *** paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame *** material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic *** response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical *** acceleration response and displacement response of different combinations are *** results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.

关键词： water supply pipe different materials shaking table test amplification factor seismic fragility

Micro-vibration suppression and compensation techniques for in-orbit satellite:A review

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Chinese Journal of Aeronautics 2024年第9期37卷 1-19页

作者： Weida XING Weixiao TUO Xingfei LI Tianyu WANG chenxi YANG State Key Laboratory of Precision Measurement Technology and Instruments Tianjin UniversityTianjin 30072China Taihu Laboratory of Deepsea Technological Science Wuxi 214123China

Micro-vibration is an important factor affecting the imaging quality and pointing accu-racy of the in-orbit *** address the problem of micro-vibration compensation,a general summary for modeling,analysis,suppression,and compensation approach should be *** this review,micro-vibration characteristics and its impacts on the payloads are firstly ***,methods for micro-vibration measurement are *** detail,the principles and practical applications of these methods are ***,advanced technologies for micro-vibration suppression are summarized from micro-vibration source attenuation,transfer path opti-mization and sensitive load *** approaches have been found to be effective for micro-vibration *** one is the Line-of-Sight(LOS)stabilization assisted with Inertial Ref-erence Unit(IRU).The other is using image restoration technology to remove the blur caused by platform *** compensation technique and research status of the two techniques are *** work will provide researchers with technical guidelines for micro-vibration suppression.

关键词： In-orbit Satellite Micro-vibration suppression Compensation technique Vibration isolation Path optimization

Hierarchical Task Planning for Power Line Flow Regulation

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 29-40页

作者： chenxi Wang Youtian Du Yanhao Huang Yuanlin Chang Zihao Guo the Ministry of Education Key Lab for Intelligent Networks and Network Security Xi'an Jiaotong UniversityXi'an 713599China the State Key Laboratory of Power Grid Safety and Energy Conservation China Electric Power Research InstituteBeijing 100192China

The complexity and uncertainty in power systems cause great challenges to controlling power *** a popular data-driven technique,deep reinforcement learning(DRL)attracts attention in the control of power ***,DRL has some inherent drawbacks in terms of data efficiency and *** paper presents a novel hierarchical task planning(HTP)approach,bridging planning and DRL,to the task of power line flow ***,we introduce a threelevel task hierarchy to model the task and model the sequence of task units on each level as a task planning-Markov decision processes(TP-MDPs).Second,we model the task as a sequential decision-making problem and introduce a higher planner and a lower planner in HTP to handle different levels of task *** addition,we introduce a two-layer knowledge graph that can update dynamically during the planning procedure to assist *** results conducted on the IEEE 1.8-bus and IEEE 300-bus systems demonstrate our HTP approach outperforms proximal policy optimization,a state-of-the-art deep reinforcement learning(DRL)approach,improving efficiency by 26.1.%and 6.86%on both systems.

关键词： Knowledge graph power line flow regulation reinforcement learning task planning

Data-Driven Fault Detection of Multiple Open-Circuit Faults for MMC Systems Based on Long Short-Term Memory Networks

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1563-1574页

作者： chenxi Fan Kaishun Xiahou Lei Wang Q.H.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

This paper presents a long short-term memory(LSTM)-based fault detection method to detect the multiple open-circuit switch faults of modular multilevel converter(MMC)systems with full-bridge sub-modules(FB-SMs).Eighteen sensor signals of grid voltages,grid currents and capacitance voltages of MMC for single and multi-switch faults are collected as sampling *** output signal characteristics of four types of single switch faults of FB-SM,as well as double switch faults in the same and different phases of MMC,are analyzed under the conditions of load variations and control command changes.A multi-layer LSTM network is devised to deeply extract the fault characteristics of MMC under different faults and operation conditions,and a Softmax layer detects the fault *** results have confirmed that the proposed LSTM-based method has better detection performance compared with three other methods:K-nearest neighbor(KNN),naive bayes(NB)and recurrent neural network(RNN).In addition,it is highly robust to model uncertainties and Gaussian *** validity of the proposed method is further demonstrated by experiment studies conducted on a hardware-in-the-loop(HIL)testing platform.

关键词： Fault detection long short-term memory(LSTM) modular multilevel converter(MMC) open circuit fault

Data-driven Reactive Power Optimization of Distribution Networks via Graph Attention Networks

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 874-885页

作者： Wenlong Liao Dechang Yang Qi Liu Yixiong Jia chenxi Wang Zhe Yang Wind Engineering and Renewable Energy Laboratory Ecole Polytechnique Federale de Lausanne(EPFL)Lausanne 1015Switzerland the College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China the Department of Electrical and Electronic Engineering(Energy Digitalization Laboratory) The University of Hong KongHong KongChina the Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong KongChina

Reactive power optimization of distribution networks is traditionally addressed by physical model based methods,which often lead to locally optimal solutions and require heavy online inference time *** improve the quality of the solution and reduce the inference time burden,this paper proposes a new graph attention networks based method to directly map the complex nonlinear relationship between graphs(topology and power loads)and reactive power scheduling schemes of distribution networks,from a data-driven *** graph attention network is tailored specifically to this problem and incorporates several innovative features such as a self-loop in the adjacency matrix,a customized loss function,and the use of max-pooling ***,a rulebased strategy is proposed to adjust infeasible solutions that violate *** results on multiple distribution networks demonstrate that the proposed method outperforms other machine learning based methods in terms of the solution quality and robustness to varying load ***,its online inference time is significantly faster than traditional physical model based methods,particularly for large-scale distribution networks.

关键词： Reactive power optimization graph neural network distribution network machine learning data-driven

Natural polysaccharide-based smart CXCR4-targeted nano-system for magnified liver fibrosis therapy

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Chinese Chemical Letters 2024年第2期35卷 341-346页

作者： Liqiong Sun Xinping Luo chenxi Zhou Zhanwei Zhou Minjie Sun College of Horticulture Nanjing Agricultural UniversityNanjing 210095China NMPA Key Laboratory for Research and Evaluation of Pharmaceutical Preparations and Excipients State Key Laboratory of Natural MedicinesDepartment of PharmaceuticsChina Pharmaceutical UniversityNanjing 210009China

Activated hepatic stellate cells(aHSCs),the main source of extracellular matrix deposition,are key targets in liver ***,no effective drug specific to aHSCs has been clinically applied due to poor drug delivery ***,we designed a CXC chemokine receptor 4(CXCR4)-targeted reactive oxygen species(ROS)-responsive platform AMD-Dex-ROS-responsive-sorafenib(ARS)based on natural polysaccharide and thioctic acid frame,which can deliver anti-fibrosis drug represented by sorafenib specifically to aHSCs on account of CXCR4 over-expression on aHSCs,and smartly disassemble via ROS-responsive thioketal rupture relying on high intracellular ROS in HSCs,realized on-demand drug release and effective liver fibrosis ***,in this platform,the CXCR4 antagonist AMD31.0 not only enhanced aHSCs targeting efficiency of sorafenib but also effectively magnified the aHSCs elimination of sorafenib by blocking stroma cell derived factor-1.SDF-1./CXCR4-induced aHSCs protection,resulting in synergistic anti-fibrosis *** platform provided a new approach for drug delivery system design and liver fibrosis treatment.

关键词： Nanoparticle CXCR4 antagonism ROS-responsive Hepatic stellate cells Liver fibrosis

Rumors and price efficiency in stock market:An empirical study of rumor verification on investor Interactive platforms

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China Journal of Accounting Research 2024年第2期17卷 164-192页

作者： Wenting Zhang chenxi Wang School of Business Sun Yat-sen UniversityChina

Using rumor verification data from investor interactive platforms,we investigate the effect of stock market rumors on price *** find favorable rumors are positively correlated with stock price synchronicity,while unfavorable rumors are negatively correlated with stock price *** favorable and unfavorable rumors are positively correlated with stock mispricing levels,and stock price crash *** tests reveal that favorable rumors about industry leaders have industry spillover *** effect of rumors on mispricing levels and stock price crash risk are more pronounced when there are more retail *** analysis shows stronger detrimental impacts of rumors on price efficiency for small-cap companies,companies with low information transparency and companies with low institutional ownership.

关键词： Rumors Price efficiency Stock price synchronicity Mispricing Stock price crash risk