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Analytical modeling on the vibration response of a beam-stiffened Mindlin thick plate with free boundary conditions

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International Journal of Mechanical System Dynamics 2023年第2期3卷 119-126页

作者： Hui guo kai Zhang School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdaoChina Department of Mechanical and Electrical Engineering Ocean University of ChinaQingdaoChina

This paper presents a new analytical solution for the vibration response of a beamstiffened Mindlin plate having a completely free boundary condition by utilizing a finite cosine integral transform.In the solution,the unknown coupling force and moments at the beam/plate interface and the unknown modal constants from the integral transform are determined by the continuity and compatibility conditions at the interface as well as the boundary conditions.It provides an easily implemented tool for exploring complex edge value problems for a class of higher-order partial differential equations represented by fully free‐stiffened Mindlin thick plates.The validity of the model is evaluated by comparing the calculated free and forced vibration responses of the beam‐stiffened plate with those calculated using a beamstiffened thin plate and those from finite element analysis.

关键词： vibration beam-stiffened mindlin thick plate free boundary condition finite integral transform

Recent Advances in Drilling Tool Temperature:A State‑of‑the‑Art Review

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 23-62页

作者： Zhaoju Zhu Xinhui Sun Kai Guo Jie Sun Jianfeng Li School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China School of Mechanical Engineering Shandong UniversityJinan 250061China

Drilling is regarded as the most complex manufacturing process compared with other conventional machining processes.During the drilling process,most of the energy consumed in metal cutting is converted to heat and increases temperature considerably.The resulting thermal phenomena are important since they influence the mode of deformation,the final metallurgical state of the machined surface,and the rate of tool wear.Hence,understanding the temperature characteristics in the drilling process is crucial for enhancing the drill performance and process efficiency.Extensive efforts have been conducted to measure and control the drilling tool temperature successively.However,very few studies have been conducted from a comprehensive perspective to review all the efforts.To address this gap in the literature,a rigorous review concerning the state-of-the-art results and advances in drilling tool temperature is presented in this paper by referring to the wide comparisons among literature analyses.The multiple aspects of drilling tool temperature are precisely detailed and discussed in terms of theoretical analysis and thermal modeling,methods for temperature measuring,the effect of cutting parameters,tool geometries and hole-making methods on temperature and temperature controlling by different cooling methods.In conclusion,several possible future research directions are discussed to offer potential insights for the drilling community and future researchers.

关键词： Drilling Tool temperature Advance materials Cutting characteristics

Quantum Spin Exchange Interactions to Accelerate the Redox Kinetics in Li–S Batteries

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Nano-Micro Letters 2024年第5期16卷 370-383页

作者： Yu Du Weijie Chen Yu Wang Yue Yu Kai Guo Gan Qu Jianan Zhang Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City College of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001People’s Republic of China

Spin-engineering with electrocatalysts have been exploited to suppress the“shuttle effect”in Li–S batteries.Spin selec-tion,spin-dependent electron mobility and spin potentials in activation barriers can be optimized as quantum spin exchange interactions lead-ing to a significant reduction of the electronic repulsions in the orbitals of catalysts.Herein,we anchor the MgPc molecules on fluorinated carbon nanotubes(MgPc@FCNT),which exhibits the single active Mg sites with axial displacement.According to the density functional theory calculations,the electronic spin polarization in MgPc@FCNT not only increases the adsorption energy toward LiPSs intermediates but also facilitates the tunneling process of electron in Li–S batter-ies.As a result,the MgPc@FCNT provides an initial capacity of 6.1 mAh cm^(-2) even when the high sulfur loading is 4.5 mg cm^(-2),and still maintains 5.1 mAh cm^(-2) after 100 cycles.This work provides a new perspective to extend the main group single-atom catalysts enabling high-performance Li–S batteries.

关键词： Metal phthalocyanines Spin polarization Electrocatalysis Li–S batteries

Investigation of mass transfer model of CO_(2) absorption with Rayleigh convection using multi-relaxation time lattice Boltzmann method

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Chinese Journal of Chemical Engineering 2022年第10期50卷 130-142页

作者： Longyun Zheng Kai Guo Hongwei Cai Bo Zhang Hui Liu Chunjiang Liu School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China State Key Laboratory of Chemical Engineering Tianjin UniversityTianjin 300072Chin

CO_(2) absorption into absorbents is a widely used method to reduce carbon emissions,in which the concentration gradient near the gas-liquid interface may induce Rayleigh convection(RC).Once RC occurs,the mass transfer rate will be significantly enhanced.Therefore,it is necessary to explore the mass transfer enhancement mechanism further and develop a penetration/surface divergence hybrid mass transfer model.In this study,we conduct research on the process of CO_(2) absorption into ethanol with RC.Firstly,we use a multi-relaxation time lattice Boltzmann method to simulate the absorption process and obtain the flow and concentration fields.And we also verify the reliability of the numerical simulation results by comparing with the experimental results.Then,we analyze the characteristics of non-uniform flow and concentration fields in RC.Moreover,we divide the near-interface region into diffusion-dominated and convection-dominated mass transfer zones by checking whether the horizontal average velocity is greater than 1.0×10^(-4) m·s^(-1).Furthermore,based on the differences in mass transfer mechanisms of the aforementioned two zones,we propose a penetration/surface divergence hybrid model to predict the instantaneous mass transfer coefficient.The prediction results demonstrate that the hybrid model can precisely predict the instantaneous mass transfer coefficient of the entire CO_(2) absorption process.Our proposed hybrid model provides a promising way to deal with the complex mass transfer problems with non-uniform flow and concentration fields.

关键词： Carbon dioxide Absorption Rayleigh convection Numerical simulation multiple-relaxation-time orgeneralized lattice Boltzmannmodel(MRT-LBM) Mass transfer

Multi-source heterogeneous data access management framework and key technologies for electric power Internet of Things

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Global Energy Interconnection 2024年第1期7卷 94-105页

作者： Pengtian guo kai Xiao Xiaohui Wang Daoxing Li China Electric Power Research Institute Co.Ltd. Beijing 100192P.R.China

The power Internet of Things(IoT)is a significant trend in technology and a requirement for national strategic development.With the deepening digital transformation of the power grid,China’s power system has initially built a power IoT architecture comprising a perception,network,and platform application layer.However,owing to the structural complexity of the power system,the construction of the power IoT continues to face problems such as complex access management of massive heterogeneous equipment,diverse IoT protocol access methods,high concurrency of network communications,and weak data security protection.To address these issues,this study optimizes the existing architecture of the power IoT and designs an integrated management framework for the access of multi-source heterogeneous data in the power IoT,comprising cloud,pipe,edge,and terminal parts.It further reviews and analyzes the key technologies involved in the power IoT,such as the unified management of the physical model,high concurrent access,multi-protocol access,multi-source heterogeneous data storage management,and data security control,to provide a more flexible,efficient,secure,and easy-to-use solution for multi-source heterogeneous data access in the power IoT.

关键词： Power Internet of Things Object model High concurrency access Zero trust mechanism Multi-source heterogeneous data

SkillSim:voice apps similarity detection

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Cybersecurity 2023年第4期6卷 33-49页

作者： Zhixiu guo Ruigang Liang guozhu Meng kai Chen SKLOIS Institute of Information EngineeringChinese Academy of SciencesBeijingChina School of Cyber Security University of Chinese Academy of SciencesBeijingChina

Virtual personal assistants(VPAs),such as Amazon Alexa and Google Assistant,are software agents designed to perform tasks or provide services to individuals in response to user commands.VPAs extend their functions through third-party voice apps,thereby attracting more users to use VPA-equipped products.Previous studies demonstrate vulnerabilities in the certification,installation,and usage of these third-party voice apps.However,these studies focus on individual apps.To the best of our knowledge,there is no prior research that explores the correlations among voice apps.Voice apps represent a new type of applications that interact with users mainly through a voice user interface instead of a graphical user interface,requiring a distinct approach to analysis.In this study,we present a novel voice app similarity analysis approach to analyze voice apps in the market from a new perspective.Our approach,called SkillSim,detects similarities among voice apps(i.***.skills)based on two dimensions:text similarity and structure similarity.SkillSim measures 30,000 voice apps in the Amazon skill market and reveals that more than 25.9%have at least one other skill with a text similarity greater than 70%.Our analysis identifies several factors that contribute to a high number of similar skills,including the assistant development platforms and their limited templates.Additionally,we observe interesting phenomena,such as developers or platforms creating multiple similar skills with different accounts for purposes such as advertising.Furthermore,we also find that some assistant development platforms develop multiple similar but non-compliant skills,such as requesting user privacy in a non-compliance way,which poses a security risk.Based on the similarity analysis results,we have a deeper understanding of voice apps in the mainstream market.

关键词： Voice app Similarity analysis Skills

Benzoselenol as an organic electrolyte additive in Li-S battery

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Nano Research 2023年第3期16卷 3814-3822页

作者： Junpeng Sun kai Zhang Yongzhu Fu Wei guo College of Chemistry Zhengzhou UniversityZhengzhou 450001China

Lithium-sulfur(Li-S)battery is one of the promising high-energy battery systems for future use.However,the shuttle effect due to the dissolved lithium polysulfides in ether electrolyte hampers its practical application.Applying electrolyte additives in Li-S battery has been widely acknowledged as an effective way to reduce the shuttle effect and improve cycling efficiency.In this work,benzoselenol(PhSeH)is used as an organic electrolyte additive in Li-S battery.It reacts with elemental sulfur to form phenyl selenosulfide,altering the redox pathway of the cathode with the regeneration of S8 at the end of charge and enabling new redox reactions with high reversibility.The Li-S coin cell with an optimized amount of PhSeH in the electrolyte delivers a high discharge capacity of 1,436 mAh·g^(−1)and a capacity retention of 92.86%in 200 cycles,and exhibits lower discharge overpotential in comparison to the cell with blank electrolyte.The Li-S pouch cell with a low electrolyte/sulfur(E/S)ratio of 4.0μL·mg^(−1)shows a discharge capacity of 1,398 mAh and excellent capacity retention for 20 cycles.

关键词： lithium-sulfur(Li-S)battery benzoselenol electrolyte additive sulfur-selenium bond electrochemical performance

Performance Analysis for Mobility Management of Dual Connectivity in HetNet

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Journal of Beijing Institute of Technology 2022年第5期31卷 505-512页

作者： Wei Huang Lin guo kai Sun College of Electronic Engineering Inner Mongolia UniversityHohhot 010021China.

Dual connectivity(DC)is regarded as a promising technology to increase users’throughput,provide radio link robustness,and improve load-balancing among base stations(BSs).However,since the introduction of DC makes the mobility of network more complex and diversified,especially the mobility management of heterogeneous networks(HetNets)based on DC faces great challenges.Taking event-A3-based measurement report as the trigger condition for handover(HO),this paper compares and evaluates the influences of HO of master nodes(MNs)and secondary nodes(SNs)on link reliability in different bearing modes.Particularly,hybrid automatic repeat request(HARQ),throughput,channel quality indicators(CQIs),and data packets queuing time are taken as link reliability analysis indicators.Besides,we study how DC utilizes the traffic split ratio between MNs and SNs to maximize the superiority of throughput.Simulation results show that DC can effectively reduce the impact of HO on the number of HARQ and increase the throughput of users.When the data traffic is tilted to the secondary nodes,the superiority of throughput is more obvious.

关键词： dual connectivity heterogeneous network(HetNet) mobility management traffic split ratio

Modeling and application of marketing and distribution data based on graph computing

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Global Energy Interconnection 2022年第4期5卷 448-460页

作者： kai Xiao Daoxing Li Xiaohui Wang Pengtian guo China Electric Power Research Institute Co.Ltd. Beijing 100192P.R.China

Integrating marketing and distribution businesses is crucial for improving the coordination of equipment and the efficient management of multi-energy systems.New energy sources are continuously being connected to distribution grids;this,however,increases the complexity of the information structure of marketing and distribution businesses.The existing unified data model and the coordinated application of marketing and distribution suffer from various drawbacks.As a solution,this paper presents a data model of"one graph of marketing and distribution"and a framework for graph computing,by analyzing the current trends of business and data in the marketing and distribution fields and using graph data theory.Specifically,this work aims to determine the correlation between distribution transformers and marketing users,which is crucial for elucidating the connection between marketing and distribution.In this manner,a novel identification algorithm is proposed based on the collected data for marketing and distribution.Lastly,a forecasting application is developed based on the proposed algorithm to realize the coordinated prediction and consumption of distributed photovoltaic power generation and distribution loads.Furthermore,an operation and maintenance(O&M)knowledge graph reasoning application is developed to improve the intelligent O&M ability of marketing and distribution equipment.

关键词： Marketing and distribution connection Graph data Graph computing Knowledge graph Data model