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Sleeve Design of Permanent-magnet Machine for Low Rotor Losses

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Chinese Journal of Electrical Engineering 2020年第4期6卷 86-96页

作者： Junqiang Zheng Wenxiang Zhao Jinghua Ji Jihong Zhu christopher h.t.lee School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China Department of Computer Science and technology Tsinghua UniversityBeijing 100000China School of Electrical and Electronic Engineering Nanyang Technological University639798Singapore

In this study,a novel rotor sleeve for permanent-magnet(PM)machines equipped with fractional-slot concentrated-windings(FSCW)is proposed.With the newly designed rotor sleeve,the rotor eddy-current(EC)losses are significantly reduced,and the torque density of the machine is improved.First,the rotor EC losses of a surface-mounted PM machine with the sleeve are analyzed.Meanwhile,the sleeve EC barriers and PM segmentation technologies for the suppression of the rotor EC losses are evaluated.Subsequently,an FSCW PM machine with the newly designed sleeve is proposed and optimized for a given set of specifications.Its electromagnetic and mechanical performances are evaluated by the finite element method(FEM).Finally,three assembling methods are presented and assessed comprehensively in terms of their merits and drawbacks.

关键词： Permanent-magnet machine rotor losses sleeve eddy-current concentrated-windings

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 benefits.to 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 efficiency.Yet,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 motors.And this also poses a negative factor for the long-term sustainable development of electric vehicles or other applications that rely heavily on rareearth PM materials.Under 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 scholars.It 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 field.this paper reviews the existing main alternatives for less-rare-earth PM motors.Based 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 motor.the operation principle,design considerations and restrictions of each type of less-rare-earth PM motor is sequentially discussed.Finally,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

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 compared.Upon 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 counterparts.however,the PM machines suffer from two major fundamental problems,namely the high material costs,and the uncontrollable flux density.By utilizing the concept of axial-field structure,the AF-FSDC machine can offer comparable torque performance as the RF-FSPM machine.hence,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

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 capability.Besides,five rotor topologies with integral-slot distributed-windings IPM machines,including four existing IPM topologies and the proposed IPM topology,are designed optimally.their 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 quantitatively.Finally,a three phase 48s8p hybrid rotor PM machine is built to verify the performances of the proposed IPM machine.this 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.

Biophotoelectrochemistry:An emerging frontier for channeling photoelectric effect into darkness zone of soils and sediments

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Pedosphere 2024年第1期34卷 5-8页

作者： Jie YE Shungui ZhOU Kenneth h.NEALSON christopher RENSING Fujian Provincial Key Laboratory of Soil Environmental health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China Department of Earth Science University of Southern CaliforniaLos Angeles CA 90007USA

Solar energy captured by photosynthetic plants in the photic zone is recognized as the main driver for the formation of organic matter utilized by soil communities. however, the contribution of organic transformation to the linkage of solar energy and microbial metabolism of soils is reduced when the vadose zone is saturated. In contrast to the conventional biophotoelectrochemistry via photosynthesis with phytoplankton during the periodic saturation of soils, recent studies suggest that non-phototrophic microorganisms in soils and sediments are able to conduct light-dependent metabolism to sustain their functionality with photosensitizers under illumination. these interactions and processes utilize long-distance electron transfer networks to interconnect diverse electron transfer chains that channel photoexcited electrons into the opaque zone for soil communities. Such an emerging process not only allows for a better understanding of biogeochemical processes such as soil carbon sequestration and mitigation, but also shows great potential for environmental treatment such as the bioremediation of contaminated soils. therefore, we suggest that biophotoelectrochemistry via photoelectric effect can have significant, heretofore unappreciated, theoretical and practical values.

关键词： soils soil metabolism

Ethanol steam reforming over Ni/ZSM-5 nanosheet for hydrogen production

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Chinese Journal of Chemical Engineering 2024年第3期67卷 247-256页

作者： Porapak Suriya Shanshan Xu Shengzhe Ding Sarayute Chansai Yilai Jiao Joseph hurd Daniel lee Yuxin Zhang christopher hardacre Prasert Reubroycharoen Xiaolei Fan Department of Chemical Engineering School of EngineeringThe University of ManchesterManchester M139PLUnited Kingdom Program of Petrochemistry and Polymer Science Faculty of ScienceChulalongkorn UniversityBangkok10330Thailand Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Liaoning Academy of Materials Shenyang 110167China Center of Excellence in Catalysis for Bioenergy and Renewable Chemicals(CBRC) andDepartment of Chemical TechnologyFaculty of ScienceChulalongkorn UniversityBangkok 10330Thailand Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo315100China

Compared to reforming reactions using hydrocarbons,ethanol steam reforming(ESR)is a sustainable alternative for hydrogen(h_(2))production since ethanol can be produced sustainably using biomass.this work explores the catalyst design strategies for preparing the Ni supported on ZSM-5 zeolite catalysts to promote ESR.Specifically,two-dimensional ZSM-5 nanosheet and conventional ZSM-5 crystal were used as the catalyst carriers and two synthesis strategies,i.e.,in situ encapsulation and wet impregnation method,were employed to prepare the catalysts.Based on the comparative characterization of the catalysts and comparative catalytic assessments,it was found that the combination of the in situ encapsulation synthesis and the ZSM-5 nanosheet carrier was the effective strategy to develop catalysts for promoting h_(2) production via ESR due to the improved mass transfer(through the 2-D structure of ZSM-5 nanosheet)and formation of confined small Ni nanoparticles(resulted via the in situ encapsulation synthesis).In addition,the resulting ZSM-5 nanosheet supported Ni catalyst also showed high Ni dispersion and high accessibility to Ni sites by the reactants,being able to improve the activity and stability of catalysts and suppress metal sintering and coking during ESR at high reaction temperatures.thus,the Ni supported on ZSM-5 nanosheet catalyst prepared by encapsulation showed the stable performance with~88% ethanol conversion and~65% h_(2) yield achieved during a 48-h longevity test at 550-C.

关键词： ZSM-5 nanosheet In situ encapsulation Ni catalyst Ethanol steam reforming hydrogen production

Early anticoagulation in patients with stroke and atrial fibrillation is associated with fewer ischaemic lesions at 1 month: the AttUNE study

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Stroke & Vascular Neurology 2024年第1期9卷 30-37,I0034页

作者： Angelos Sharobeam Longting Lin Christina Lam Carlos Garcia-Esperon Yash Gawarikar Ronak Patel Matthew lee-Archer Andrew Wong Michael Roizman Amanda Gilligan Andrew lee Kee Meng tan Susan Day christopher Levi Stephen M Davis Mark Parsons Bernard Yan Melbourne Brain Centre at Royal Melbourne hospital ParkvilleVictoriaAustralia University of New South Wales South Western Sydney Clinical School LiverpoolNew South WalesAustralia Department of Neurology John Hunter HospitalNewcastleNew South WalesAustralia Department of Neurology Calvary Public HospitalCanberraAustralian Capital TerritoryAustralia Department of Neurology Northern Hospital EppingEppingVictoriaAustralia Department of Neurology Royal Brisbane and Women's HospitalHerstonQueenslandAustralia the University of Queensland School of Medicine HerstonQueenslandAustralia Neurosciences Clinical Institute Epworth HealthcareRichmondVirginiaAustralia Department of Neurology Austin HealthUniversity of MelbourneHeidelbergVictoriaAustralia Flinders University College of Medicine and Public health AdelaideSouth AustraliaAustralia Department of Neurology Gold Coast University HospitalSouthportQueenslandAustralia the University of Sydney Northern Clinical School St LeonardsNew South WalesAustralia Department of Neurology and Neurophysiology Liverpool HospitalLiverpoolNew South WalesAustralia

Background the optimal time to commence anticoagulation in patients with atrial fibrillation(AF)after ischaemic stroke or transient ischaemic attack(tIA)is unclear,with guidelines differing in recommendations.A limitation of previous studies is the focus on clinically overt stroke,rather than radiologically obvious diffusion-weighted imaging ischaemic lesions.We aimed to quantify silent ischaemic lesions and haemorrhages on MRI at 1month in patients commenced on early(te(≥4days)anticoagulation.We hypothesised that there would be fewer ischaemic lesions and more haemorrhages in the early anticoagulant group at 1-month MRI.Methods A prospective multicentre,observational cohort study was performed at 11 Australian stroke centres.Clinical and MRI data were collected at baseline and follow-up,with blinded imaging assessment performed by two authors.timing of commencement of anticoagulation was at the discretion of the treating stroke physician.Results We recruited 276 patients of whom 208 met the eligibility criteria.the average age was 74.2 years(SD±10.63),and 79(38%)patients were female.Median National Institute of health Stroke Scale score was 5(IQR 1–12).Median baseline ischaemic lesion volume was 5mL(IQR 2–17).there were a greater number of new ischaemic lesions on follow-up MRI in patients commenced on anticoagulation≥4days after index event(17%vs 8%,p=0.04),but no difference in haemorrhage rates(22%vs 32%,p=0.10).Baseline ischaemic lesion volume of≤5mL was less likely to have a new haemorrhage at 1month(p=0.02).there was no difference in haemorrhage rates in patients with an initial ischaemic lesion volume of>5mL,regardless of anticoagulation timing.Conclusion Commencing anticoagulationter stroke or tIA is associated with fewer ischaemic lesions at 1month in AF patients.there is no increased rate of haemorrhage with early anticoagulation.these results suggest that early anticoagulation after mild-to-moderate acute ischaemic stroke associated with AF might be safe,but randomised controlled s

关键词： patients lesions ischaemic

tocotrienol isoforms:the molecular mechanisms underlying their effects in cancer therapy and their implementation in clinical trials

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Journal of Integrative Medicine 2024年第1期22卷 1-11页

作者： Maria Younes Ghady Loubnane christopher Sleiman Sandra Rizk Department of Natural Sciences Lebanese American UniversityByblosLebanon

tocotrienols are found in a variety of natural sources,like rice bran,annatto seeds and palm oil,and have been shown to have several health-promoting properties,particularly against chronic diseases such as cancer.the incidence of cancer is rapidly increasing around the world,not only a result of continued aging and population growth,but also due to the adoption of aspects of the Western lifestyle,such as high-fat diets and low-physical activity.the literature provides strong evidence that tocotrienols are able to inhibit the growth of various cancers,including breast,lung,ovarian,prostate,liver,brain,colon,myeloma and pancreatic cancers.these findings,along with the reported safety profile of tocotrienols in healthy human volunteers,encourage further research into these compounds’potential use in cancer prevention and treatment.the current review provided detailed information about the molecular mechanisms of action of different tocotrienol isoforms in various cancer models and evaluated the potential therapeutic effects of different vitamin E analogues on important cancer hallmarks,such as cellular proliferation,apoptosis,angiogenesis and metastasis.MEDLINE/PubMed and Scopus databases were used to identify recently published articles that investigated the anticancer effects of vitamin E derivatives in various types of cancer in vitro and in vivo along with clinical evidence of adjuvant chemopreventive benefits.Following an overview of pre-clinical studies,we describe several completed and ongoing clinical trials that are paving the way for the successful implementation of tocotrienols in cancer chemotherapy.

关键词： Vitamin E tocotrienols Cancer Molecular mechanism Clinical trials

IgE-Mast cell mediated allergy: a sensor of food quality

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Signal transduction and targeted therapy 2024年第1期9卷 8-9页

作者： christopher C.Udoye Rudolf A.Manz Institute for Systemic Inflammation Research University of LübeckLübeckGermany

In two recent studies published in Nature,Florsheim et al.and Plum et al.reported that allergic-specific reactions induced by immunoglobulin(Ig)E mediated mast cell activation is crucial for the timely induction of antigen-avoidance behaviour.1,2 these studies prove the concept that allergic sensitization triggers the formation of avoidance behaviour and define the underlying molecular mechanism.

关键词： allergic mechanism