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2022 International Conference on Electrical Machines, ICEM 2022

作者： Yang, Zhanlu Wang, Shanming Tsinghua University State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Beijing100084 China Navy Submarine Academy Qingdao266100 China

ISBN: (数字)9781665414326

ISBN: (纸本)9781665414326

For the rotating armature permanent magnet motor (RAPMM), the rotor slot move relating to the stator, which causes the variation of electromagnetic excitation force and the slot-frequency vibration. In order to reduce the slot-frequency vibration of RAPMM, a slotless rotating armature permanent magnet motor (SRAPMM) is proposed and prototyped. The magnetic field, torque, and torque ripple are simulated by finite element method, which shows that the air gap flux density and the radial force keep nearly constant. Vibration experiments were carried out on two SRAPMMs with different magnetic pole widths. The results show that when the motor is no-loaded, the frequency of the main vibration is even times of the current frequency. After the motor is loaded, the amplitude of the electromagnetic vibration is significantly smaller than that caused by mechanical reasons, indicating that the SRAPMM is a good alternative in the application of strict requirements for vibration. © 2022 IEEE.

关键词： Permanent magnets

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Numerical analysis of vehicle-bridge coupling vibration concerning nonlinear stress-dependent damping

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Frontiers of Structural and Civil engineering 2022年第2期16卷 239-249页

作者： Pengfei LI Jinquan ZHANG Shengqi MEI Zhenhua DONG Yan MAO Bridge and Tunnel Technology Research Center Research Institute of HighwayMinistry of TransportBeijing100088China National Engineering Laboratory of Bridge Structure Safety Technology Research Institute of HighwayMinistry of TransportBeijing100088China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China School of Civil Engineering Shijiazhuang Tiedao UniversityShijiazhuang050043China

Damping is known to have a considerable influence on the dynamic behavior of *** fixed damping ratios recommended in design codes do not necessarily represent the complicated damping characteristics of bridge *** study investigated the application of stress-dependent damping associated with vehicle-bridge coupling vibration and based on that investigation proposed the stress-dependent damping *** results of the investigation show that the stress-dependent damping ratio is significantly different from the constant damping ratio(5%)defined in the standard *** vehicles travel at speeds of 30,60,and 90,the damping ratios of the bridge model are 3.656%,3.658%,and 3.671%,*** peak accelerations using the regular damping ratio are 18.9%,21.3%,and 14.5%of the stress-dependent damping ratio,*** the vehicle load on the bridge is doubled,the peak acceleration of the mid-span node increases by 5.4 times,and the stress-related damping ratio increases by 2.1%.A corrugated steel-web bridge is being used as a case study,and the vibration response of the bridge is compared with the measured *** acceleration response of the bridge which was calculated using the stress-dependent damping ratio is significantly closer to the measured acceleration response than that using the regular damping ratio.

关键词： vehicle-bridge vibration system dynamic analysis stress-dependent damping energy dissipation

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A Battery Model Parameter Identification Method Considering Topology Reconfiguration 20

A Battery Model Parameter Identification Method Considering ...

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20th International Conference on AC and DC Power Transmission 2024, ACDC 2024

作者： Chen, Aizuo Quan, Yue Zhou, Yanglin Lei, Ertao Zhang, Junkun Ci, Song Department of Electrical Engineering Tsinghua University Beijing100084 China Electric Power Research Institute of Guangdong Power Grid Co. Ltd. Guangdong 510080 China State Key Laboratory of Power System Operation and Control Tsinghua University Beijing100084 China

ISBN: (纸本)9781837242672

In the field of battery circuit model parameter estimation, the combination of bilinear transformation with the least squares method has garnered widespread attention due to its excellent performance under continuous current conditions. However, in dynamic reconfigurable battery network (DRBN), the network's topological structure is constantly changing, and the battery current consists of non-periodic pulse signal sequences, making it challenging for traditional methods to accurately estimate the battery model parameters within such networks. To address this issue, this paper proposes a lithium-ion battery circuit model parameter estimation method that takes into account network topology reconfiguration. This method, based on the operational modes and sampling methods of DRBN, derives a new discrete transformation formula for the transfer function and constructs a least squares model parameter identification model using this formula. By establishing an experimental platform for DRBN, the effectiveness of the proposed method is validated in this paper. © The Institution of engineering & Technology 2024.

关键词： Network topology

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Realization of quantum secure direct communication over 100 km fiber with time-bin and phase quantum states

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Light(Science & Applications) 2022年第5期11卷 787-795页

作者： Haoran Zhang Zhen Sun Ruoyang Qi Liuguo Yin Gui-Lu Long Jianhua Lu State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijingChina Beijing Academy of Quantum Information Science BeijingChina School of Information and Technology Tsinghua UniversityBeijingChina Beijing Institute of Spacecraft System Engineering BeijingChina Frontier Science Center for Quantum Information BeijingChina Beijing National Research Center for Information Science and Technology BeijingChina

Rapid progress has been made in quantum secure direct communication in recent *** practical application,it is important to improve the performances,such as the secure information rate and the communication *** this paper,we report an elaborate physical system design and protocol with much enhanced *** design increased the secrecy capacity greatly by achieving an ultra-low quantum bit error rate of<0.1%,one order of magnitude smaller than that of existing *** to previous systems,the proposed scheme uses photonic time-bin and phase states,operating at 50 MHz of repetition rate,which can be easily upgraded to over 1 GHz using current on-the-shelf *** results of our experimentation demonstrate that the proposed system can tolerate more channel loss,from 5.1 dB,which is about 28.3 km in fiber in the previous scheme,to 18.4 dB,which corresponds to fiber length of 102.2 ***,the experiment shows that intercity quantum secure direct communication through fiber is feasible with present-day technology.

关键词： fiber communication quantum

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Electromagnetic Scattering Characteristics of Different Polarized Electromagnetic Waves by High Voltage Transmission Lines

Electromagnetic Scattering Characteristics of Different Pola...

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International Conference on Wireless Power Transfer, ICWPT 2022

作者： Ma, Xianglin Lu, Yanxia Jiao, Chaoqun Zhang, Jianggong Zhao, Zhibin Gan, Zheyuan School of Electrical Engineering Beijing Jiaotong University Beijing100044 China State Key Laboratory of Power Grid Environmental Protection China Electric Power Research Institute Wuhan430073 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China

ISBN: (纸本)9789819906307

With the construction of high-voltage transmission lines and various stations, the passive interference of large-scale tower arrays to various stations is becoming more and more serious. In order to obtain the passive interference law of different types of polarized electromagnetic waves, the electromagnetic scattering model of transmission lines is established. The passive interference law of circularly polarized electromagnetic wave is obtained by simulating two kinds of polarized electromagnetic wave. Taking frequency, distance and tower cardinality as variables, the difference of passive interference law between the two polarized electromagnetic waves is analyzed. Finally, it is concluded that the passive interference level of circularly polarized electromagnetic wave is generally less than that of vertically polarized electromagnetic wave, and the variation law of frequency and array coefficient is different. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Electric lines

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Comparison of bulk snow density measurements using different methods

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Advances in Climate Change Research 2024年第4期15卷 658-668页

作者： Hang SU Xin-Yue ZHONG Bin CAO Yuan-Tao HU Lei ZHENG Tingjun ZHANG State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Key Laboratory of Remote Sensing of Gansu Province Heihe Remote Sensing Experimental Research StationNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Tibetan Plateau Earth System Environment and ResourcesNational Tibetan Plateau Data CenterInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Climate Centre of Shaanxi Province Xi'an71000China School of Geospatial Engineering and Science Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Laboratory of Westem China's Environmental Systems(Ministry of Education).College of Earth and Environmental Sciences Lanzhou Universiny Lanzhou 730000China

Snow density is one of the basic properties used to describe snow cover characteristics,and it is critical for remote sensing retrieval,water resources assessment and modeling *** are many instruments available to measure snow density in ***,there are mea-surement errors of snow density for bulk and layers or gravimetric and electronic instruments,which may affect the accuracy of remote sensing retrieval and model *** in China,due to the noticeable heterogeneity of snowpacks,it is necessary to evaluate in detail the performance and applicability of snow density instruments in different snowpack *** study evaluated the performance of different snow density instruments:the Federal Sampler,the model VS-43 snow density cylinder(VS-43),the wedge snow density cutter(WC1000 and WC25O),and the Snow *** average bulk snow density of all instrument measurements was set as the reference value for *** results showed that as compared with the reference,the VS-43 cylinder presented the best performance for bulk snow density measurement in the measured range with the lowest RMSE(11 kg m^(-3)),BIAS(3 kg m^(-3)),and MRE(1.6%).For layer observation,bulk snow density was overestimated by 8.1%with WC1000 and underestimated by 11.4%with Snow Fork which was the worst performance compared with the reference value,and there were greater measurement errors of snow density in the depth hoar than other snow *** with grassland,the uncertainty of snow density measurements was slightly lower in ***,the Federal Sampler and VS-43 cylinder are more suitable for bulk snow density measurement in deep snowpack regions across China,and it is recommended to use WC1000,WC250 and Snow Fork to measure the snow density of snow layers in the snow stratigraphy.

关键词： Snowdensity Measurement Uncertainty comparison

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The analysis of aging characteristics of RTV insulating coatings with varying silicone rubber contents 10

The analysis of aging characteristics of RTV insulating coat...

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2024 10th International Conference on Applied Materials and Manufacturing Technology, ICAMMT 2024

作者： Zhang, Xinxin Zhou, Yuanxiang Zhu, Xiaoqian Yu, Jingzhe Huang, Xiaolong Su, Bin Liu, Min Fan, Shuochao State Key Laboratory of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China North China Electric Power Research Institute Co. Ltd. Beijing100045 China State Grid Jibei Electric Power Co. Ltd. Beijing100052 China

Room-temperature vulcanized silicone rubber coatings are widely used in the field of high-voltage outdoor insulation. Silicone rubber (RTV-SIR) coatings are used to improve the anti-pollution flashover performance of high-voltage ceramic insulators by imparting hydrophobicity to the surface. Different high-temperature aging experiments were conducted on coating samples with varying silicone rubber contents, and their physicochemical properties were tested to analyze the aging mechanisms involved, aiming to further evaluate the lifespan of the coatings. It was observed that lower silicone rubber content led to more significant changes in surface functional groups, accelerated degradation of coating properties during aging, and increased susceptibility to microcrack formation and subsequent crack development, further promoting the aging process. The aging process accelerated gradually from the surface to deeper layers at the same temperature, resulting in increased disorder and densification of the three-dimensional network structure, along with fragmentation of low-molecular-weight molecules. © Published under licence by IOP Publishing Ltd.

关键词： Silicone coatings

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Template-Based Collaborative Design Task Management for complex Products 7

Template-Based Collaborative Design Task Management for Comp...

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2020 7th International Conference on Computer-Aided Design, Manufacturing, Modeling and simulation, CDMMS 2020

作者： Zhou, Junhua Xue, Junjie Shi, Guoqiang State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System Engineering Beijing100854 China

The task template system of this system combines the business requirements of the work and provides the classification management function of work packages and work package templates. At the same time, data integration with other systems such as the main data system and resource library is realized. Through this system, users can instantiate a single work package to form a single work item, and can also establish the front and back relationship of the work package through the work package template, thereby realizing the instantiation of the work package process. © Published under licence by IOP Publishing Ltd.

关键词： Data integration

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10-Million Atoms simulation of First-Principle Package LS3DF

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Journal of Computer Science & Technology 2024年第1期39卷 45-62页

作者：严昱瑾李海波赵曈汪林望石林刘涛谭光明贾伟乐孙凝晖 State Key Laboratory of Processors Institute of Computing TechnologyChinese Academy of SciencesBeijing 100190 China University of Chinese Academy of Sciences Beijing 101408China Computing System Optimization Laboratory Huawei TechnologiesBeijing 100094China Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China School of Materials Science and Engineering Yancheng Institute of TechnologyYancheng 224051China

The growing demand for semiconductor devices simulation poses a big challenge for large-scale electronic structure *** various methods,the linearly scaling three-dimensional fragment(LS3DF)method exhibits excellent scalability in large-scale *** on algorithmic and system-level optimizations,we propose a highly scalable and highly efficient implementation of LS3DF on a domestic heterogeneous supercomputer equipped with *** terms of algorithmic optimizations,the original all-band conjugate gradient algorithm is refined to achieve faster convergence,and mixed precision computing is adopted to increase overall *** terms of system-level optimiza-tions,the original two-layer parallel structure is replaced by a coarse-grained parallel *** strategies such as multi-stream,kernel fusion,and redundant computation removal are proposed to increase further utilization of the com-putational power provided by the heterogeneous *** a result,our optimized LS3DF can scale to a 10-million sili-con atoms system,attaining a peak performance of 34.8 PFLOPS(21.2% of the peak).All the improvements can be adapt-ed to the next-generation supercomputers for larger simulations.

关键词： single instruction multiple thread accelerator electronic structure high-performance computing linearly scaling three-dimensional fragment(LS3DF)

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Targeting Ultra-Emitters for Effective Methane Mitigation in China’s Coal Sector

ACS ES&T Air

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ACS ES&T Air 2024年第7期1卷 734-742页

作者： Helan Wang Bo Zheng Hui Li Qiang Zhang Kebin He Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration Institute of Environment and Ecology Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen 518055 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084 China Department of Earth System Science Ministry of Education Key Laboratory for Earth System Modeling Institute for Global Change Studies Tsinghua University Beijing 100084 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China

The energy system fuels climate change as the largest emitter of global greenhouse gases, while a lack of transparent, infrastructure-level information undermines efforts to cut emissions. Coal mining has been the largest emitter of methane (CH4) in China over the past 10 years, which is not tracked at the mine level, and effective mitigation pathways have yet to be established. Herein, we develop a state-of-the-art CH4emission database, comprising 3343 active coal mines in China, by harmonizing multisource information. The results suggest that China’s coal mines emitted 15.8 ± 5.1 million metric tons CH4yr–1in 2019. Those with CH4emission intensities >2 standard deviations above the national mean accounted for 4% of China’s coal production, yet they generated 23% of China’s coal CH4emissions. We project a steady decline in China’s coal CH4emissions by >75% in 2100 compared to 2019 levels under three different scenarios, due to reduced coal demand during energy transition. Targeting ultra-emitters for mine closure will accelerate emission reductions in the midterm and achieve deep CH4emission cuts by >92% in 2100, which buys us time to control global warming. Our idealized mine closure strategy serves as a cost-effective CH4mitigation strategy to enable swift climate action.

关键词： Biological databases Climate Coal Energy Hydrocarbons

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