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Concept, configuration, and application of on-board nanogrids for use in electric vehicles

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Science China(Technological Sciences) 2024年第7期67卷 2053-2073页

作者： ZHAO Bing LI Yong WU fang WAN JiangHu CAI JiuQing YANG HaiTao LIU fang College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Wuhan Second Ship Design and Research Institute Wuhan 430000China School of Automation Central South UniversityChangsha 410083China

Against the backdrop of increasingly serious climate change, researchers are attempting to extend macroscale carbon reduction research to smaller scales. With the rapid development and widespread application of electric vehicles(EVs), an effective approach for carbon reduction based on EVs has the potential to be developed. To coordinate and manage the EV platform in diverse application scenarios, the concept of an on-board nanogrid(OBNG), in which a nanogrid is combined with the EV, is proposed and defined, and the characteristics summarized. A configuration that includes a physical layer with the on-board hardware system;an information layer for logical control, energy management, and communication coordination;and an application layer that can cope with different working environments is proposed. A detailed introduction to the basic architecture and management mode of each layer is provided along with information concerning the relevant technologies for coordinated operation. New ideas and approaches to improve the existing performance are proposed, and finally, combined with a background of smart and low-carbon cities, major application scenarios are envisioned.

关键词： electric vehicle nanogrid energy management hybrid energy storage power electronics converter

On Hamiltonian Property of Cayley Digraphs

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 547-556页

作者： fang DUAN Qiong-xiang HUANG School of Mathematics Science Xinjiang Normal UniversityUrumqi 830017China College of Mathematics and Systems Science Xinjiang UniversityUrumqi 830017China

Let G be a finite group generated by S and C(G,S) the Cayley digraphs of G with connection set *** this paper,we give some sufficient conditions for the existence of hamiltonian circuit in C(G,S),where G=Zm×H is a semiproduct of Zmby a subgroup H of *** particular,if m is a prime,then the Cayley digraph of G has a hamiltonian circuit unless G=Zm×*** addition,we introduce a new digraph operation,called φ-semiproduct of Γ1by Γ2and denoted by Γ1×Γ_φΓ2,in terms of mapping φ:V(Γ2)→{1,-1}.Furthermore we prove that C(Zm,{a})×_φ C(H,S) is also a Cayley digraph if φ is a homomorphism from H to{1,-1} ≤ Zm~*,which produces some classes of Cayley digraphs that have hamiltonian circuits.

关键词： Cayley digraphs hamiltonian circuit external semidirect product

Trudinger–Moser Inequalities on a Closed Riemann Surface with a Symmetric Conical Metric

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2263-2284页

作者： Yu fang Yun Yan YANG College of Teacher Education Quzhou UniversityQuzhou 324003P.R.China Department of Mathematics Renmin University of ChinaBeijing 100872P.R.China

This is a continuation of our previous work(*** ***.,20,1295–1324,2020).Let(Σ,g)be a closed Riemann surface,where the metric g has conical singularities at finite *** G is a group whose elements are isometries acting on(Σ,g).Trudinger–Moser inequalities involving G are established via the method of blow-up analysis,and the corresponding extremals are also *** extends previous results of Chen(***.,1990),Iula–Manicini(Nonlinear Anal.,2017),and the authors(2020).

关键词： Trudinger-Moser inequality blow-up analysis conical singularity

Assessment and Enhancement of FRC of Power Systems Considering Thermal Power Dynamic Conditions

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1371-1383页

作者： Feng Hong Yalei Pang Weiming Ji Lu Liang fang fang Junhong Hao Jizhen Liu State Key Laboratory of Alternate Electric Power System with Renewable Energy Sources and School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Alternate Electric Power System with Renewable Energy Sources School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China

Frequency stability and security have been a vital challenge as large-scale renewable energy is integrated into power *** contrast,the proportion of traditional thermal power units decreases during the decarbonization transformation process,resulting in poor frequency *** paper aims to explore the potential of frequency regulation support,dynamic assessment,and capacity promotion of thermal power plants in the transition *** the dynamic characteristics of the main steam working fluid under different working conditions,a nonlinear observer is constructed by extracting the main steam pressure and valve opening degree *** real-time frequency modulation capacity of thermal power units can provide a dynamic state for the power grid.A dynamic adaptive modification for primary frequency control(PFC)of power systems,including wind power and thermal power,is proposed and *** power dynamic allocation factor is adaptively optimized by predicting the speed droop ratio,and the frequency modulation capability of the system is improved by more than 11%under extreme ***,through the Monte Carlo simulation of unit states of the system under various working conditions,the promotion of the frequency regulation capacity with high wind power penetration(WPP)is verified.

关键词： Dynamic evaluation frequency regulation power system predictive modeling wind penetration

Life forms affect beta-diversity patterns of larch forests in China

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Plant Diversity 2024年第1期46卷 49-58页

作者： Wenjing fang Qiong Cai Chengjun Ji Jiangling Zhu Zhiyao Tang Jingyun fang School of Ecology and Environmental Science Yunnan UniversityKunming 650091China Department of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China

Beta-diversity reflects the spatial changes in community species composition which helps to understand how communities are assembled and biodiversity is formed and maintained. Larch(Larix) forests, which are coniferous forests widely distributed in the mountainous and plateau areas in North and Southwest China, are critical for maintaining the environmental conditions and species diversity. Few studies of larch forests have examined the beta-diversity and its constituent components(species turnover and nestedness-resultant components). Here, we used 483 larch forest plots to determine the total betadiversity and its components in different life forms(i.e., tree, shrub, and herb) of larch forests in China and to evaluate the main drivers that underlie this beta-diversity. We found that total betadiversity of larch forests was mainly dependent on the species turnover component. In all life forms,total beta-diversity and the species turnover component increased with increasing geographic, elevational, current climatic, and paleoclimatic distances. In contrast, the nestedness-resultant component decreased across these same distances. Geographic and environmental factors explained 20%-25% of total beta-diversity, 18%-27% of species turnover component, and 4%-16% of nestedness-resultant component. Larch forest types significantly affected total beta-diversity and species turnover component. Taken together, our results indicate that life forms affect beta-diversity patterns of larch forests in China, and that beta-diversity is driven by both niche differentiation and dispersal limitation. Our findings help to greatly understand the mechanisms of community assemblies of larch forests in China.

关键词： Beta-diversity Species turnover Nestedness-resultant Geographic distance Climatic distance Larch forest

Ultrafast optical investigation of carrier and spin dynamics in low-dimensional perovskites

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Science China(Technological Sciences) 2024年第1期67卷 2-18页

作者： FU JinYue JIANG Ying fang HongHua Key Laboratory for Micro-Nano Physics and Technology of Hunan Province School of Physics and ElectronicsHunan UniversityChangsha 410012China State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China

Low-dimensional perovskite(PVK)materials have attracted significant research interest,because of their quantum-confined effect,tunable band gap structures,and higher stability than that of three-dimensional(3D)*** semiconductor optoelectronic devices,high speed and small size are closely *** development of high-speed devices requires researchers to fully understand the properties of materials,especially the dynamic processes such as carrier recombination,separation,and transport,which often play a crucial role in the performance of *** an indispensable part of dynamic research,spin relaxation is also of great significance in studying the properties of materials and explore possible *** halide PVK materials have strong spin-orbit coupling(SOC),which provides a basis for information storage and processing by using spin degrees of ***,studying the carrier and spin dynamics of low-dimensional PVKs is an effective way to understand the internal properties of low-dimensional PVKs *** paper summarizes the latest research progress on the ultrafast carrier and spin dynamics in low-dimensional PVKs,to comprehensively understand their carrier and spin behaviors and present an outlook for relevant studies in this area.

关键词： low-dimensional perovskites carrier dynamics spin dynamics optoelectronic devices

Exploring battery material failure mechanisms through synchrotron X-ray characterization techniques

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Journal of Energy Chemistry 2024年第7期94卷 128-135页

作者： Lingzhe fang Xiaozhao Liu Tao Li Department of Chemistry and Biochemistry Northern Illinois UniversityDeKalbIL 60115USA X-ray Science Division and Joint Center forEnergy Storage Research Argonne National LaboratoryLemontIL6439UA

Rechargeable battery cycling performance and related safety have been persistent *** is crucial to decipher the capacity fading induced by electrode material failure via a range of *** these,synchrotron-based X-ray techniques with high flux and brightness play a key role in understanding degradation *** this comprehensive review,we summarize recent advancements in degra-dation modes and mechanisms that were revealed by synchrotron X-ray ***,an overview of X-ray absorption spectroscopy and X-ray scattering techniques is introduced for charac-terizing failure phenomena at local coordination atomic environment and long-range order crystal struc-ture scale,*** last,we envision the future of exploring material failure mechanism.

关键词： Battery failure Synchrotron-based techniques X-ray scattering X-ray absorption spectroscopy

Low-thermal-budget synthesis of monolayer MoS2

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Science China Materials 2024年第1期67卷 372-374页

作者： Zongmeng Yang Shibo fang Jing Lu State Key Laboratory for Mesoscopic Physics and School of Physics Peking University Collaborative Innovation Center of Quantum Matter Beijing Key Laboratory for Magnetoelectric Materials and Devices (BKL-MEMD) Peking University Peking University Yangtze Delta Institute of Optoelectronics Key Laboratory for the Physics and Chemistry of Nanodevices Peking University Beijing Key Laboratory of Quantum Devices Peking University

Two-dimensional (2D) materials, such as MoS2, have been considered as a competitive coordinate for future electronics due to their excellent electrostatics and high mobility [1–3]. Moreover, the potential integration of 2D materials with silicon circuits can present increased density and multifunction in future heterogeneously integrated circuits [4,5]. However, the high thermal-budget during Mo S2 synthesis exceeds the temperature requirement of direct integration with Si in the back-end-of-line (BEOL) fabrication process [6–8].

关键词： FILMS

A rigorous real-time acoustic positioning method for ocean bottom seismic exploration

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Satellite Navigation 2024年第1期5卷 168-190页

作者： Jinye Ma Shouchuan fang Jianhu Zhao School of Geodesy and Geomatics Wuhan University129 Luoyu RoadWuhan430079China Institute of Marine Science and Technology Wuhan UniversityWuhan430079China Surveying Service Center BGP Inc.CNPCZhuozhou072751HebeiChina

The conventional technique for positioning seafloor geophones in ocean bottom seismic exploration encounters several challenges,including the significant impact of outliers on positioning results,underutilization of high-precision observations,and low efficiency in real-time data *** issues inevitably affect the quality of seismic exploration *** address these challenges and enhance the accuracy of geophone positioning,this paper proposes a rigorous real-time acoustic positioning method for geophones based on sequential adjustment and Baarda's outlier detection *** proposed method comprises three key steps:grouping the original acoustic observations,constructing the intra-group acoustic positioning model,and synthesizing the positioning results across the different *** validity and practicality of this approach are confirmed through a simulation experiment as well as the field experiment conducted in the Bohai Sea,*** results demonstrate that the proposed method effectively eliminates outliers in the original observations and maximizes the utilization of high-quality *** to traditional acoustic positioning methods,it significantly reduces positioning errors from meters to decimeters,and in some cases can achieve centimeter-level *** the sound velocity profile in the operating sea area is measured,the method can attain the posterior standard deviation at the millimeter level and positioning errors within 10 *** the sound velocity profile is unknown,the method can achieve the posterior standard deviation at centimeter-level and positioning errors of approximately 20 cm.

关键词： Ocean bottom seismic exploration Geophone positioning Acoustic positioning method Sequential adjustment Outlier detection