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Comparison of Flux-Switching Machines With and Without Permanent Magnets

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Chinese Journal of Electrical Engineering 2015年第1期1卷 78-84页

作者： christopher h.t.lee K.t.Chau C.C.Chan Department of Electrical and Electronic Engineering The University of Hong KongHong KongChina

In this paper,three advanced flux-switching(FS)machines,namely the radial-field flux-switching permanent-magnet(RF-FSPM)machine,the radial-field flux-switching DC-field(RF-FSDC)machine,and the axial-field FSDC(AF-FSDC)machine are quantitatively *** the installation of the high-energy-density PM materials,the RF-FSPM machine can definitely provide the superior torque performances as compared to its magnetless ***,the PM machines suffer from two major fundamental problems,namely the high material costs,and the uncontrollable flux *** utilizing the concept of axial-field structure,the AF-FSDC machine can offer comparable torque performance as the RF-FSPM ***,with the consideration of the cost-effectiveness and the control flexibility,the magnetless AF-FSDC machine has exhibited promising potential in various applications.

关键词： Flux-switching magnetless radial-field axial-field cost-effectiveness

technology trends,challenges,and opportunities of reduced-rare-earth PM motor for modern electric vehicles

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Green Energy and Intelligent transportation 2022年第1期1卷 63-81页

作者： Shiyue Zheng Xiaoyong Zhu Zixuan Xiang Lei Xu Li Zhang christopher h.t.lee School of Electrical and Information Engineering Jiangsu UniversityZhenjiangChina Nanyang technological University Singapore

Nowadays,with increasing concerns about environmental pollution and energy crisis electric vehicles are rapidly developing owing to their significant environmental-friendly *** meet the diverse driving requirements of electric vehicles,the PM motors with high-performance rare-earth PMs have been widely employed in electric vehicle powertrains,which shows the performance merits of high power density and high ***,rare-earth PMs,as non-renewable strategic resources,usually suffer from unstable supply and fluctuation prices,which increases the potential risks of further large-scale application of rare-earth PM *** this also poses a negative factor for the long-term sustainable development of electric vehicles or other applications that rely heavily on rareearth PM *** this background,a type of less-rare-earth PM motors,which aims to effectively alleviate the dependence of high-performance PM motors on rare-earth PMs,has recently drawn increasing attention from experts and *** implies that the investigation and development of less-rare-earth PM motors without compromising performances is becoming a new and hot research direction in the motor *** paper reviews the existing main alternatives for less-rare-earth PM *** on the dominated torque component,the less-rareearth PM motors are divided into two types,which are the less-rare-earth PM-dominated motor and less-rare-earth PM-assisted *** operation principle,design considerations and restrictions of each type of less-rare-earth PM motor is sequentially ***,combined with the potential electric vehicle application,the key problems of less-rare-earth PM motor are summarized and the corresponding technological means are prospected.

关键词： Electric vehicles Permanent magnet motors Rare-earth materials Permanent magnet

基于双重空间死区补偿的五相电机多参数分布辨识方法

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中国电机工程学报 2024年第23期44卷 9442-9452,I0028页

作者：唐琛樊英陈俊磊 christopher h.t.lee 东南大学电气工程学院江苏省南京市210096 新加坡南洋理工大学电气与电子工程学院新加坡639798

针对逆变器死区会使五相永磁同步电机基波及谐波空间产生非正弦畸变,降低参数辨识精度的问题,提出一种双重空间死区补偿方法。针对传统侵入式辨识方法对系统干扰大的问题,充分结合参数影响因素,提出一种新的基于自饱和及交叉耦合的多参... 详细信息

针对逆变器死区会使五相永磁同步电机基波及谐波空间产生非正弦畸变,降低参数辨识精度的问题,提出一种双重空间死区补偿方法。针对传统侵入式辨识方法对系统干扰大的问题,充分结合参数影响因素,提出一种新的基于自饱和及交叉耦合的多参数分布辨识方法。首先,采用d轴偏置电流注入方法,获得所有运行工况的dq轴电感在线辨识结果;其次,利用四阶方程拟合电感辨识数据;最后,结合拟合方程对定子电阻和转子磁链进行在线辨识。所提方法的合理性通过一台五相内置式永磁同步样机的仿真及实验结果进行验证。

关键词：五相永磁同步电机死区补偿四矢量SVPWM 参数辨识磁饱和

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Improvement torque Performances of Interior Permanent-Magnet Machines

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CES transactions on Electrical Machines and Systems 2019年第1期3卷 12-18页

作者： Junqiang Zheng Wenxiang Zhao christopher h.t.lee Jinghua Ji Gaohong Xu School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore

Due to their excellent efficiency,power density and constant power speed region,interior permanent-magnet(IPM)machines are very suitable for electric vehicles(EVs).this paper proposed a new IPM rotor topology,which can offer high reluctance torque,wide constant power speed range and excellent overload ***,five rotor topologies with integral-slot distributed-windings IPM machines,including four existing IPM topologies and the proposed IPM topology,are designed *** characteristics,which include d-q axis inductances,saliency ratios,electromagnetic torques,corresponding torque ripples,back-electromotive forces(EMFs),overload capabilities and flux weakening performances are evaluated ***,a three phase 48s8p hybrid rotor PM machine is built to verify the performances of the proposed IPM *** work provides some general concepts for machine developers who are willing to build IPM machines for high-performance EV applications.

关键词： Flux weakening finite-element analysis(FEA) interior permanent-magnet brushless machine reluctance torque inductance.

Apples to oranges:environmentally derived,dynamic regulation of serotonin neuron subpopulations in adulthood?

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Neural Regeneration Research 2025年第9期20卷 2596-2597页

作者： christopher J.O’Connell Matthew J.Robson Department of Genetics College of MedicineHarvard UniversityBostonMAUSA James L.Winkle College of Pharmacy Division of Pharmaceutical SciencesUniversity of CincinnatiCincinnatiOHUSA Neuroscience Graduate Program College of MedicineUniversity of CincinnatiCincinnatiOHUSA

traumatic brain injury(tBI)is a public health problem with an undue economic burden that impacts nearly every age,ethnic,and gender group across the globe(Capizzi et al.,2020).tBIs are often sustained during a dynamic range of exposures to energetic environmental forces and as such outcomes are typically heterogeneous regarding severity and pathology(Capizzi et al.,2020).

关键词： sustained orange dynamic

Design to reduce electromagnetic vibration in integral-slot SPM machine considering force modulation effect

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Science China(technological Sciences) 2022年第8期65卷 1867-1877页

作者： ZhU ShengDao ZhAO WenXiang JI Jinghua LIU Guohai lee christopher h.t. School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore

In this paper, two different designs, with dummy slots and bread-loaf magnets techniques, are presented to reduce the electromagnetic vibration in integral-slot surface-mounted permanent-magnet(SPM) machines. Firstly, the stator slotting effect on the magnetic field modulation and radial force modulation is investigated. It reveals the amplitude of the modulated magnetic field and modulated radial force is greatly affected by the slot opening effect, while the spatial order is closely associated with the slot numbers. Subsequently, the dummy slots and bread-loaf magnets design are developed for a 36-slot/12-pole integral-slot SPM machine to reduce the electromagnetic vibration. Finally, two SPM machines, with conventional and bread-loaf magnets,are manufactured. Experimental tests are carried out to validate the theoretical analyses.

关键词： surface-mounted permanent-magnet machine slot opening width dummy slots bread-loaf magnets vibration reduction

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Comparative analysis of empirical and deep learning models for ionospheric sporadic E layer prediction

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Earth and Planetary Physics 2025年第1期9卷 10-19页

作者： BingKun Yu Penghao tian Xianghui Xue christopher JScott haiLun Ye JianFei Wu Wen Yi tingDi Chen XianKang Dou Institute of Deep Space Sciences Deep Space Exploration LaboratoryHefei 230088China CAS Key Laboratory of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China hefei National Laboratory University of Science and Technology of ChinaHefei 230088China Department of Meteorology University of ReadingReading RG66BBUK

Sporadic E(Es)layers in the ionosphere are characterized by intense plasma irregularities in the E region at altitudes of 90-130 *** they can significantly influence radio communications and navigation systems,accurate forecasting of Es layers is crucial for ensuring the precision and dependability of navigation satellite *** this study,we present Es predictions made by an empirical model and by a deep learning model,and analyze their differences comprehensively by comparing the model predictions to satellite RO measurements and ground-based ionosonde *** deep learning model exhibited significantly better performance,as indicated by its high coefficient of correlation(r=0.87)with RO observations and predictions,than did the empirical model(r=0.53).this study highlights the importance of integrating artificial intelligence technology into ionosphere modelling generally,and into predicting Es layer occurrences and characteristics,in particular.

关键词： ionospheric sporadic E layer radio occultation ionosondes numerical model deep learning model artificial intelligence

Raster Voronoi tessellation and Its Application to Emergency Modeling

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Geo-Spatial Information Science 2011年第4期14卷 235-245页

作者： Ickjai lee Kyungmi lee christopher torpelund-Bruin School of Business(It) James Cook University

Due to the advances in Web technologies,various raster maps are available through Web Map Services such as Google maps and Yahoo *** online maps are used to visualize diverse types of *** disasters with these online maps has become an important research *** this article,we propose a map-based general-purpose emergency management support system based on a computational model of generalized(multiplicatively weighted,order-k,and Minkowski-metric)Voronoi *** proposed system tessellates Web maps and models disasters(or emergency response units)having different weights in the complete order from 1 to k-1 in the three popular Minkowski metrics(Euclidean,Manhattan,and Maximum distance)pro-vide insightful information for various what-if emergency *** proposed map-based emergency management support system systematically supports neighboring queries,districting queries,location optimization queries,and routing *** pro-vide specific examples to illustrate how our system supports these queries.

关键词： raster Voronoi diagrams emergency management systems generalized Voronoi diagrams decision support systemsCLC number P208

Influence of residual stresses on failure pressure of cylindrical pressure vessels

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Chinese Journal of Aeronautics 2013年第6期26卷 1415-1421页

作者： M.Jeyakumar t.christopher Department of Mechanical Engineering Sardar Raja College of EngineeringAlangulamTirunelveli 627 808India Department of Mechanical Engineering Government College of EngineeringTirunelveli 627 007India

the utilization of pressure vessels in aerospace applications is *** this work,fnite element analysis（FEA）has been carried out using ANSYS software package with 2D axisymmetric model to access the failure pressure of cylindrical pressure vessel made of AStM A36 carbon steel having weld-induced residual *** fnd out the effect of residual stresses on failure pressure,frst an elasto-plastic analysis is performed to fnd out the failure pressure of pressure vessel not having residual *** a thermo-mechanical fnite element analysis is performed to assess the residual stresses developed in the pressure vessel during *** one more elasto-plastic analysis is performed to assess the effect of residual stresses on failure pressure of the pressure vessel having residual *** analysis indicates reduction in the failure pressure due to unfavorable residual stresses.

关键词： Aerospace engineering AStM A36 Finite element analysis Pressure vessels Welding residual stress