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A Correlation-Based Stochastic Model for Massive MIMO Channel

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China Communications 2024年第1期21卷 175-187页

作者： Yang Liu Gang Li Chengxiang Wang National Mobile Communications research Laboratory School of Information Science and EngineeringSoutheast UniversityNanjing 211189China School of internet of things engineering Jiangnan UniversityWuxi 214122China Pervasive Communication research center Purple Mountain LaboratoriesNanjing 211111China

In this paper,the channel impulse response matrix(CIRM)can be expressed as a sum of couplings between the steering vectors at the base station(BS)and the eigenbases at the mobile station(MS).Nakagami distribution was used to describe the fading of the coupling between the steering vectors and the eigenbases.Extensive measurements were carried out to evaluate the performance of this proposed model.Furthermore,the physical implications of this model were illustrated and the capacities are analyzed.In addition,the azimuthal power spectrum(APS)of several models was analyzed.Finally,the channel hardening effect was simulated and discussed.Results showed that the proposed model provides a better fit to the measured results than the other CBSM,i.e.,Weichselberger model.Moreover,the proposed model can provide better tradeoff between accuracy and complexity in channel synthesis.This CIRM model can be used for massive MIMO design in the future communication system design.

关键词： CBSM channel capacity channel hardening channel modeling massive MIMO

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

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Nano-Micro Letters 2024年第7期16卷 402-440页

作者： Yizhe Li Yajie Li Hao Sun Liyao Gao Xiangrong Jin Yaping Li Zhi LV Lijun Xu Wen Liu Xiaoming Sun State Key Laboratory of Chemical Resource engineering Beijing Advanced Innovation Center for Soft Matter Science EngineeringCollege of ChemistryBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China Xinjiang Coal Mine Mechanical and Electrical engineering technology research center Xinjiang Institute of EngineeringUrumqi 830023Xinjiang Uygur Autonomous RegionPeople’s Republic of China

The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.

关键词： Dual-atom catalysts Synergetic effect Electrocatalysis Oxygen reduction reaction CO_(2)reduction reaction Hydrogen evolution reaction N2 reduction reaction

Energy Harvesting in the Wake of An Inverted C-Shaped Bluff Body

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China Ocean engineering 2024年第1期38卷 68-80页

作者： WANG Jun-lei LI Shen-fang Md.Mahbub ALAM ZHU Hong-jun HU Guo-biao School of Mechanical and Power engineering Zhengzhou UniversityZhengzhou 450000China center for Turbulence Control Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China internet of things Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China

This paper proposes a novel wake-induced vibration(WIV)-based energy harvesting system consisting of two bluff bodies.An inverted C-shaped bluff body is stationary installed at the upstream position to generate an interference wake street,and a cylinder bluff body equipped with a transducer is elastically suspended at the downstream position to harness WIV energy.The hydrodynamics and energy harvesting(EH)performance of the proposed system are investigated via experimental studies.The reduced velocity(U*)ranging from 2 to 14(the corresponding Reynolds number ranging from 15100 to 106200)is considered in the present study.It is found that the wake generated by the inverted C-shaped bluff body significantly affects the EH performance.Enlarging the opening angle(α)of the C-shaped bluff body increases the vibration amplitude of the downstream cylinder,thereby increasing the harvested power.When the spacing(L)between two bluff bodies is two times the cylinder diameter(D),the wake-induced vibration(WIV)mode is observed,while the combined WIV and wake galloping(WG)mode occurs whenαis 150°,and L equals 3D or 4D.The average drag coefficient becomes negative when L is 2D,3D,or 4D.By carefully configuring a C-shaped bluff body,the wake generated by it can bring an augmenting effect on the vibration of the downstream EH cylinder.For example,the RMS power output of the proposed EH system reaches a maximum of 0.31 W at U*=8 and L=4D,which is 300%greater than that of its traditional counterpart.Furthermore,after a number of case stud-ies,it is identified that the proposed EH system can achieve the best performance whenαis 150°and L=2D.

关键词： wake-induced vibration vortex-induced vibration galloping energy harvesting bluff body

Key Technologies and Prospects for Electric Vehicles Within Emerging Power Systems: Insights from Five Aspects

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 439-447页

作者： Yalun Li Minggao Ouyang C.C.Chan Xueliang Sun Yonghua Song Wei Cai Yilin Xie Yuqiong Mao Department of Electrical engineering and School of Vehicle and MobilityTsinghua UniversityBeijing 100084China School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China Department of Electrical and Electronic engineering The University of Hong KongHong Kong 999077China Department of Mechanical and Materials engineering University of Western OntarioLondonON N6A 3K7Canada State Key Laboratory of internet of things for Smart City University of MacaoTaipaMacao 999078China Department of Electrical engineering Tsinghua UniversityBeijing 100084China School of Electrical and Electronic engineering Harbin University of Science and TechnologyHarbin 150080China

The energy revolution requires coordination in energy consumption, supply, storage and institutional systems.Renewable energy generation technologies, along with their associated costs, are already fully equipped for large-scale promotion.However, energy storage remains a bottleneck, and solutions areneeded through the use of electric vehicles, which traditionallyplay the role of energy consumption in power systems. Toclarify the key technologies and institutions that support EVsas terminals for energy use, storage, and feedback, the CSEEJPES forum assembled renowned experts and scholars in relevantfields to deliver keynote reports and engage in discussions ontopics such as vehicle–grid integration technology, advancedsolid-state battery technology, high-performance electric motortechnology, and institutional innovation in the industry chain.These experts also provided prospects for energy storage andutilization technologies capable of decarbonizing new powersystems.

关键词： Electric vehicles engineering philosophy highpower density motor new power system solid state batteries vehicle grid integration.

IoTDQ: An Industrial IoT Data Analysis Library for Apache IoTDB

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Big Data Mining and Analytics 2024年第1期7卷 29-41页

作者： Pengyu Chen Wendi He Wenxuan Ma Xiangdong Huang Chen Wang School of Software Tsinghua UniversityBeijing 100084China National engineering research center for Big Data Software(NERCBDS) Tsinghua UniversityBeijing 100084China

There is a growing demand for time series data analysis in industry areas.Apache loTDB is a time series database designed for the internet of things(loT)with enhanced storage and I/O performance.With User-Defined Functions(UDF)provided,computation for time series can be executed on Apache loTDB directly.To satisfy most of the common requirements in industrial time series analysis,we create a UDF library,loTDQ,on Apache loTDB.This library integrates stream computation functions on data quality analysis,data profiling,anomaly detection,data repairing,etc.loTDQ enables users to conduct a wide range of analyses,such as monitoring,error diagnosis,equipment reliability analysis.It provides a framework for users to examine loT time series with data quality problems.Experiments show that loTDQ keeps the same level of performance compared to mainstream alternatives,and shortens I/O consumption for Apache loTDB users.

关键词： industrial big data data quality data mining and analytics

Endogenous Security Formal Definition,Innovation Mechanisms,and Experiment research in Industrial internet

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Tsinghua Science and technology 2024年第2期29卷 492-505页

作者： Hongsong Chen Xintong Han Yiying Zhang School of Computer and Communication engineering University of Science and Technology BeijingBeijing 100083China

With the rapid development of information technologies,industrial internet has become more open,and security issues have become more challenging.The endogenous security mechanism can achieve the autonomous immune mechanism without prior knowledge.However,endogenous security lacks a scientific and formal definition in industrial internet.Therefore,firstly we give a formal definition of endogenous security in industrial internet and propose a new industrial internet endogenous security architecture with cost analysis.Secondly,the endogenous security innovation mechanism is clearly defined.Thirdly,an improved clone selection algorithm based on federated learning is proposed.Then,we analyze the threat model of the industrial internet identity authentication scenario,and propose cross-domain authentication mechanism based on endogenous key and zero-knowledge proof.We conduct identity authentication experiments based on two types of blockchains and compare their experimental results.Based on the experimental analysis,Ethereum alliance blockchain can be used to provide the identity resolution services on the industrial *** of things Application(IOTA)public blockchain can be used for data aggregation analysis of internet of things(IoT)edge nodes.Finally,we propose three core challenges and solutions of endogenous security in industrial internet and give future development directions.

关键词： industrial internet endogenous security architecture federated learning blockchain

Low-Carbon Dispatching for Virtual Power Plant with Aggregated Distributed Energy Storage Considering Spatiotemporal Distribution of Cleanness Value

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 346-358页

作者： Hongchao Gao Tai Jin Guanxiong Wang Qixin Chen Chongqing Kang Jingkai Zhu State Key Laboratory of Power System Operation and Control Department of Electrical EngineeringTsinghua UniversityBeijing 100084China Sichuan Energy internet research Institute Tsinghua University Chengdu 200016China Power Dispatching and Control center of Shanghai Municipal Electric Power Company Shanghai 200122China IEEE

The scale of distributed energy resources is increasing,but imperfect business models and value transmission mechanisms lead to low utilization ratio and poor responsiveness.To address this issue,the concept of cleanness value of distributed energy storage(DES)is proposed,and the spatiotemporal distribution mechanism is discussed from the perspectives of electrical energy and cleanness.Based on this,an evaluation system for the environmental benefits of DES is constructed to balance the interests between the aggregator and the power system operator.Then,an optimal low-carbon dispatching for a virtual power plant(VPP)with aggregated DES is constructed,where-in energy value and cleanness value are both considered.To achieve the goal,a green attribute labeling method is used to establish a correlation constraint between the nodal carbon potential of the distribution network(DN)and DES behavior,but as a cost,it brings multiple nonlinear relationships.Subsequently,a solution method based on the convex envelope(CE)linear re-construction method is proposed for the multivariate nonlinear programming problem,thereby improving solution efficiency and feasibility.Finally,the simulation verification based on the IEEE 33-bus DN is conducted.The simulation results show that the multidimensional value recognition of DES motivates the willingness of resource users to respond.Meanwhile,resolving the impact of DES on the nodal carbon potential can effectively alleviate overcompensation of the cleanness value.

关键词： Distributed energy storage virtual power plant(VPP) spatiotemporal distribution low-carbon dispatching

空间选择性缺陷管理制备高性能碳基CsPbI_(3)钙钛矿太阳能电池

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Science Bulletin 2024年第8期69卷 1050-1060页

作者：王海亮张啟先林则东刘慧丛魏晓震宋永发律春宇李卫平朱立群王科翔崔振华王兰林常青殷鹏刚宋廷鲁白阳陈棋杨世和陈海宁 School of Materials Science and engineering Beihang UniversityBeijing 100191China Guangdong Provincial Key Lab of Nano-Micro Materials research School of Advanced MaterialsShenzhen Graduate SchoolPeking UniversityShenzhen 518055China Institute of Biomedical engineering Shenzhen Bay LaboratoryShenzhen 518107China School of Chemistry Beihang UniversityBeijing 100191China beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications MIIT Key Laboratory for Low-Dimensional Quantum Structure and DevicesExperimental Center of Advanced MaterialsSchool of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China School of internet of things engineering Jiangnan UniversityWuxi 214122China School of Physical Science and technology Guangxi UniversityNanning 530004China Experimental center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China

Defects formed at the surface,buried interface and grain boundaries(GB)of CsPbI_(3)perovskite films considerably limit photovoltaic performance.Such defects could be passivated effectively by the most prevalent post modification strategy without compromising the photoelectric properties of perovskite films,but it is still a great challenge to make this strategy comprehensive to different defects spatially distributed throughout the films.Herein,a spatially selective defect management(SSDM)strategy is developed to roundly passivate various defects at different locations within the perovskite film by a facile one-step treatment procedure using a piperazine-1,4-diium tetrafluoroborate(PZD(BF_(4))_(2))solution.The small-size PZD^(2+)cations could penetrate into the film interior and even make it all the way to the buried interface of CsPbI_(3)perovskite films,while the BF_(4)^(-)anions,with largely different properties from I^(-)anions,mainly anchor on the film surface.Consequently,virtually all the defects at the surface,buried interface and grain boundaries of CsPbI_(3)perovskite films are effectively healed,leading to significantly improved film quality,enhanced phase stability,optimized energy level alignment and promoted carrier transport.With these films,the fabricated CsPbI_(3)PSCs based on carbon electrode(C-PSCs)achieve an efficiency of18.27%,which is among the highest-reported values for inorganic C-PSCs,and stability of 500 h at 85℃with 65%efficiency maintenance.

关键词： CsPbI_(3) Defects Spatially selective defect management Carbon electrode

Free-walking:Pedestrian inertial navigation based on dual foot-mounted IMU

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Defence technology（防务技术） 2024年第3期33卷 573-587页

作者： Qu Wang Meixia Fu Jianquan Wang Lei Sun Rong Huang Xianda Li Zhuqing Jiang Yan Huang Changhui Jiang School of Automation Science and Electrical engineering University of Science and Technology BeijingBeijing100083China Shunde Innovation School University of Science and Technology BeijingFo Shan528399China research Institute of China Unicom Beijing100190China School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China Department of Automation Tsinghua University Beijing100084China GEOLOC Laboratory Universite Gustave EiffelParis77454France

The inertial navigation system(INS),which is frequently used in emergency rescue operations and other situations,has the benefits of not relying on infrastructure,high positioning frequency,and strong real-time performance.However,the intricate and unpredictable pedestrian motion patterns lead the INS localization error to significantly diverge with time.This paper aims to enhance the accuracy of zero-velocity interval(ZVI)detection and reduce the heading and altitude drift of foot-mounted INS via deep learning and equation constraint of dual feet.Aiming at the observational noise problem of low-cost inertial sensors,we utilize a denoising autoencoder to automatically eliminate the inherent noise.Aiming at the problem that inaccurate detection of the ZVI detection results in obvious displacement error,we propose a sample-level ZVI detection algorithm based on the U-Net neural network,which effectively solves the problem of mislabeling caused by sliding windows.Aiming at the problem that Zero-Velocity Update(ZUPT)cannot suppress heading and altitude error,we propose a bipedal INS method based on the equation constraint and ellipsoid constraint,which uses foot-to-foot distance as a new observation to correct heading and altitude error.We conduct extensive and well-designed experiments to evaluate the performance of the proposed method.The experimental results indicate that the position error of our proposed method did not exceed 0.83% of the total traveled distance.

关键词： Indoor positioning Inertial navigation system(INS) Zero-velocity update(ZUPT) internet of things(IoTs) Location-based service(LBS)