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Eruption Sequence of the Lower Permanent Dentition of Lufengpithecus lufengensis 被引量:1
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作者 ZHAO Ling-xia LU Qing-wu HE Zhu-fang 《人类学学报》 CSCD 北大核心 2002年第S1期14-18,共5页
The paper aims to reconstruct the eruption sequence of the permanent teeth of Lufengpithecus lufengensis. Eruption sequence here means the order of appearance of the tooth crowns out of the alveolar crypt. The permane... The paper aims to reconstruct the eruption sequence of the permanent teeth of Lufengpithecus lufengensis. Eruption sequence here means the order of appearance of the tooth crowns out of the alveolar crypt. The permanent dental developments of five juvenile mandibles are observed and analyzed via radiograph. Using such records as the stages of crown and root formation, location of the crown occlusion relative to the alveolar margin, and wear degrees of the erupted teeth, the eruption sequence of the mandibular permanent teeth of Lufengpithecus lufengensis is reasonably derived as M1 I1 I2 M2 P3 P4 C M3. This order is seen to differ very markedly from that in modern humans, and to be similar to that in apes. 展开更多
关键词 Eruption sequence of mandible dentition Lufengpithecus lufengensis
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Toward understanding the microstructure characteristics,phase selection and magnetic properties of laser additive manufactured Nd-Fe-B permanent magnets 被引量:1
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作者 Bo Yao Nan Kang +6 位作者 Xiangyu Li Dou Li Mohamed EL Mansori Jing Chen Haiou Yang Hua Tan Xin Lin 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第1期277-294,共18页
Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infue... Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder. 展开更多
关键词 laser additive manufacturing(LAM) Nd-Fe-B permanent magnets numerical simulation microstructure magnetic properties
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Current knowledge for the risk factors of early permanent pacemaker implantation following transcatheter aortic valve replacement and what is next for the primary prevention? 被引量:1
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作者 Gen-Min Lin Wei-Chun Huang Chih-Lu Han 《World Journal of Cardiology》 2024年第2期54-57,共4页
In this editorial,we comprehensively summarized the preoperative risk factors of early permanent pacemaker implantation after transcatheter aortic valve replacement(TAVR)among patients with severe aortic stenosis from... In this editorial,we comprehensively summarized the preoperative risk factors of early permanent pacemaker implantation after transcatheter aortic valve replacement(TAVR)among patients with severe aortic stenosis from several renowned clinical studies and focused on the primary prevention of managing the modifiable factors,e.g.,paroxysmal atrial fibrillation before the TAVR. 展开更多
关键词 permanent pacemaker implantation Transcatheter aortic valve replacement Interventricular conduction delay DIABETES Supraventricular arrhythmia
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Disturbances rejection optimization based on improved two-degree-of-freedom LADRC for permanent magnet synchronous motor systems 被引量:1
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作者 Chenggang Wang Jianhu Yan +2 位作者 Wenlong Li Liang Shan Le Sun 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期518-531,共14页
Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturba... Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturbance suppression and have poor performance in suppressing complex nonlinear disturbances.In order to address these issues,this paper proposes an improved two-degree-of-freedom LADRC(TDOF-LADRC)strategy,which can enhance the disturbance rejection performance of the system while decoupling entirely the system's dynamic and anti-disturbance performance to boost the system robustness and simplify controller parameter tuning.PMSM models that consider total disturbances are developed to design the TDOF-LADRC speed controller accurately.Moreover,to evaluate the control performance of the TDOF-LADRC strategy,its stability is proven,and the influence of each controller parameter on the system control performance is analyzed.Based on it,a comparison is made between the disturbance observation ability and anti-disturbance performance of TDOF-LADRC and CLADRC to prove the superiority of TDOF-LADRC in rejecting disturbances.Finally,experiments are performed on a 750 W PMSM experimental platform,and the results demonstrate that the proposed TDOF-LADRC exhibits the properties of two degrees of freedom and improves the disturbance rejection performance of the PMSM system. 展开更多
关键词 permanent magnet synchronous motor(PMSM) Active disturbance rejection control(ADRC) Disturbance observer Two-degree-of-freedom control ANTI-DISTURBANCE
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Research progress of permanent ferrite magnet materials
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作者 XU Bin CHEN Yu-feng +3 位作者 ZHOU Yu-juan LUO Bi-yun ZHONG Shou-guo LIU Xing-ao 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第6期1723-1762,共40页
Permanent ferrite magnet materials are extensively employed due to their exceptional magnetic properties and cost-effectiveness.The fast development in electromobile and household appliance industries contributes to a... Permanent ferrite magnet materials are extensively employed due to their exceptional magnetic properties and cost-effectiveness.The fast development in electromobile and household appliance industries contributes to a new progress in permanent ferrite materials.This paper reviews the deveolpement and progress of permanent ferrite magnet industry in recent years.The emergence of new raw material,the advancement of perparation methods and manufacturing techniques,and the potential applications of permanent ferrite materials are introduced and discussed.Specifically,nanocrystallization plays a crucial role in achieving high performance at a low cost and reducing reliance on rare earth resources,and therefore it could be a promising development trendency. 展开更多
关键词 permanent ferrite magnetic materials HIGH-PERFORMANCE nanosizing
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Effect of antioxidants on the efficiency of jet milling and the powder characteristics of Sm2Co17 permanent magnets
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作者 Da-Shuai Xu Lei Liu +6 位作者 Jian-Hui Yuan Bo Zhou Chuang-Hui Dong Feng-Qing Wang Yong Ding Ying-Li Sun A-Ru Yan 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期615-620,共6页
This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that a... This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that adding antioxidants helps improve the dispersion among magnetic powders,leading to a 33.3%decrease in jet milling time and a 15.8%increase in magnet powder production yield.Additionally,adding antioxidants enhances the oxidation resistance of the magnetic powders.After being stored in a constant temperature air environment at 25C for 48 h,the O content in the powder decreased by 33%compared to samples without antioxidants.While in the magnet body,the O content decreased from 0.21 wt.%to 0.14 wt.%,which helps increase the effective Sm content and domain wall pinning uniformity in the magnet.Excellent magnetic properties were obtained in the magnet with added antioxidants:B_(r)=11.6 kGs,SF=79.6%,H_(cj)=16.8 kOe,and(BH)_(max)=32.5 MGOe. 展开更多
关键词 ANTIOXIDANT SmCo permanent magnet oxidation resistance grinding efficiency
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Multiple pulp stones emerge across all teeth during mixed dentition:A case report
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作者 Yuan Lv Jie Zhu +3 位作者 Cheng-Tao Fu Le Liu Jing Wang Yan-Feng Li 《World Journal of Clinical Cases》 SCIE 2024年第22期5189-5195,共7页
BACKGROUND This paper reports a rare presentation of multiple pulp stones(PSs)emerging in all teeth during mixed dentition.It offers valuable insights into the clinical diagnosis,treatment,and prognosis of multiple PS... BACKGROUND This paper reports a rare presentation of multiple pulp stones(PSs)emerging in all teeth during mixed dentition.It offers valuable insights into the clinical diagnosis,treatment,and prognosis of multiple PSs,shedding light on their occurrence during the mixed dentition period.CASE SUMMARY A 10-year-old girl presented with repeated pain in the mandibular right posterior teeth.Intraoral examination revealed carious lesions,abnormal tooth shapes,and anomalies in tooth number.Radiographic examinations showed multiple PSs with diverse shapes,sizes,and quantities in all teeth,alongside anomalies in tooth shape and number.Root canal therapy was initiated,but the patient initially lacked timely follow-up.Upon return for treatment completion,an extracted tooth revealed irregular calculus within the pulp cavity.CONCLUSION This case underscores the importance of considering multiple PSs in mixed dentition,necessitating comprehensive evaluation and management strategies. 展开更多
关键词 Mixed dentition Multiple pulp stones Pulp calcification Cone-beam computed tomography Case report
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Parental Knowledge of Pre-Hospital Management of Avulsed Permanent Tooth in Children at Kath
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作者 Ama Agyeibea Amuasi Samuel K. Addo Solomon Obiri-Yeboah 《Open Journal of Stomatology》 2024年第2期87-102,共16页
BACKGROUND: Permanent tooth avulsion is one of the severe forms of dental traumatic injuries. The immediate action taken at the site of the accident is crucial to the prognosis of the tooth. Replantation is considered... BACKGROUND: Permanent tooth avulsion is one of the severe forms of dental traumatic injuries. The immediate action taken at the site of the accident is crucial to the prognosis of the tooth. Replantation is considered as the treatment of choice. OBJECTIVE: The study was undertaken to assess the knowledge of parents who accompany their children to the pediatric dental clinic, KATH on the pre-hospital management of avulsed permanent tooth in children. METHODS: A researcher administered structured questionnaire was used to collect data on the knowledge of pre-hospital management of avulsed permanent tooth from 83 parents who accompanied their wards to the pediatric dental clinic at KATH. RESULTS: A total of 83 parents were involved in the study. 30 (36%) were males while 53 (64%) were females. The majority of the parents (57%) were either university trained or had attended college of education. Only 32 parents (39%) were aware of the possibility of replantation. Majority of the parents chose non-physiologic media as the transport media of choice and only 10% would attempt self-replantation before seeking professional help. 76 parents (92%) had no previous education on pre-hospital management of avulsed tooth. CONCLUSION: The results obtained from this study indicate that parental knowledge on pre-hospital management of avulsed permanent tooth is low hence the need for massive public educational campaigns. 展开更多
关键词 Parental Knowledge Tooth Avulsion Pre-Hospital Management permanent Tooth
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Improved Particle Swarm Optimization for Parameter Identification of Permanent Magnet Synchronous Motor
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作者 Shuai Zhou Dazhi Wang +2 位作者 Yongliang Ni Keling Song Yanming Li 《Computers, Materials & Continua》 SCIE EI 2024年第5期2187-2207,共21页
In the process of identifying parameters for a permanent magnet synchronous motor,the particle swarm optimization method is prone to being stuck in local optima in the later stages of iteration,resulting in low parame... In the process of identifying parameters for a permanent magnet synchronous motor,the particle swarm optimization method is prone to being stuck in local optima in the later stages of iteration,resulting in low parameter accuracy.This work proposes a fuzzy particle swarm optimization approach based on the transformation function and the filled function.This approach addresses the topic of particle swarmoptimization in parameter identification from two perspectives.Firstly,the algorithm uses a transformation function to change the form of the fitness function without changing the position of the extreme point of the fitness function,making the extreme point of the fitness function more prominent and improving the algorithm’s search ability while reducing the algorithm’s computational burden.Secondly,on the basis of themulti-loop fuzzy control systembased onmultiplemembership functions,it is merged with the filled function to improve the algorithm’s capacity to skip out of the local optimal solution.This approach can be used to identify the parameters of permanent magnet synchronous motors by sampling only the stator current,voltage,and speed data.The simulation results show that the method can effectively identify the electrical parameters of a permanent magnet synchronous motor,and it has superior global convergence performance and robustness. 展开更多
关键词 Transformation function filled function fuzzy particle swarm optimization algorithm permanent magnet synchronous motor parameter identification
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Risk of permanent pacemaker implantation following transcatheter aortic valve replacement:Which factors are most relevant?
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作者 Akash Batta Juniali Hatwal 《World Journal of Cardiology》 2024年第2期49-53,共5页
Transcatheter aortic valve replacement(TAVR)has emerged as a formidable treatment option for severe symptomatic aortic stenosis ahead of surgical aortic valve replacement.The encouraging results from large randomized ... Transcatheter aortic valve replacement(TAVR)has emerged as a formidable treatment option for severe symptomatic aortic stenosis ahead of surgical aortic valve replacement.The encouraging results from large randomized controlled trials has resulted in an exponential rise in the use of TAVR even in the low-risk patients.However,this is not without challenges.Need for permanent pacemaker(PPM)post-TAVR remains the most frequent and clinically relevant challenge.Naturally,identifying risk factors which predispose an individual to develop high grade conduction block post-TAVR is important.Various demographic factors,electrocardiographic features,anatomic factors and procedural characteristics have all been linked to the development of advanced conduction block and need for PPM following TAVR.Amongst these electrophysiological variables,most notably a prolonged QRS>120 ms regardless of the type of conduction block seems to be one of the strongest predictors on logistic regression models.The index study by Nwaedozie et al highlights that patients requiring PPM post-TAVR had higher odds of having a baseline QRS>120 ms and were more likely to be having diabetes mellitus that those who did not require PPM. 展开更多
关键词 Transcatheter aortic valve replacement permanent pacemaker Diabetes mellitus QRS duration Electrophysiological variables
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Review of Field Weakening Control Strategies of Permanent Magnet Synchronous Motors
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作者 Runze Jing Gaolin Wang +1 位作者 Guoqiang Zhang Dianguo Xu 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第3期319-331,共13页
Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the s... Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the speed range under finite DC-bus voltage,extensive research on field weakening(FW)control strategies has been conducted.This paper summarizes the major FW control strategies of PMSMs,which are categorized into calculation-based methods,voltage closed-loop control methods,and model predictive control related methods.The existing strategies are analyzed and compared according to performance,robustness,and execution difficulty,which can facilitate the implementation of FW control. 展开更多
关键词 Calculation-based methods Field weakening control Model predictive control permanent magnet synchronous motor OVERMODULATION Voltage closed-loop control
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Effect of Brisk Walking on Self-Care Agency or Care Dependency among Colorectal Cancer Patients with Permanent Stoma
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作者 Zhen Zhang Anabella G.Javier 《Journal of Clinical and Nursing Research》 2024年第5期68-82,共15页
Objective:The purpose of this study was to determine the effectiveness of brisk walking as an intervention for self-care agency and care dependency in patients with permanent colorectal cancer stoma.Method:This study ... Objective:The purpose of this study was to determine the effectiveness of brisk walking as an intervention for self-care agency and care dependency in patients with permanent colorectal cancer stoma.Method:This study adopted a quasi-experimental research design,specifically a non-equivalent control group pre-test and post-test design.Utilizing the Exercise of Self-Care Agency Scale(ESCA)and Care Dependency Scale(CDS),a survey was administered to 64 patients from a hospital in Shandong Province.The statistical methods used for analyzing data included frequency,mean,standard deviation(SD),independent t-test,P-value calculation,and dependent t-test.Result:After two months of a brisk walking exercise program,participants in the experimental group had a higher level of self-care agency than before the experiment(P<0.05),and their level of care dependency was significantly reduced(P<0.05).Participants in the control group also showed higher levels of self-care agency(P<0.05)and lower levels of care dependency(P<0.05)after two months compared to their levels before the two months.Conclusion:The brisk walking program had a positive impact on patients’self-care agency and reduced their care dependency. 展开更多
关键词 permanent stoma Colorectal cancer Brisk walking Self-care agency Care dependency
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Cogging Torque Reduction in Axial Flux PMSM with Different Permanent Magnet Combination 被引量:2
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作者 WANG Xiaoguang LIU Cheng +2 位作者 ZHOU Sheng WAN Ziwei LIU Yi 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第5期726-736,共11页
With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increas... With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increased.To solve the problem of oversized cogging torque of axial flux PMSM,a rotor topology with hybrid permanent magnet is proposed to weaken the cogging torque.Firstly,the expression of the cogging torque of the axial flux motor is derived,and the influence of the pole-arc ratio of the permanent magnet on the cogging torque is analyzed.Secondly,the rotor structure with hybrid permanent magnet is adopted to reduce the cogging torque.According to the analytical analysis,the constraints of the size and pole-arc ratio between the hybrid permanent magnets are obtained,and the two permanent magnets related to the minimum cogging torque are determined.And the analysis results are verified by the finite element simulation.Furthermore,the motor performance with and without the hybrid permanent magnet is compared with each other.Finally,the cogging torque is significantly reduced by adopting a rotor structure with hybrid permanent magnets. 展开更多
关键词 axial flux permanent magnet synchronous motor(AFPMSM) rotor structure cogging torque hybrid permanent magnet pole-arc ratio
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Transient characteristics analysis of linear flux-switching permanent magnet machines for precision control
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作者 周士贵 余海涛 +2 位作者 胡敏强 黄磊 袁榜 《Journal of Southeast University(English Edition)》 EI CAS 2011年第1期31-35,共5页
A dynamical dq model is proposed for a linear flux-switching permanent magnet(LFSPM) machine which is suitable for high-precision control applications.The operation principle of the prototype machine is analyzed usi... A dynamical dq model is proposed for a linear flux-switching permanent magnet(LFSPM) machine which is suitable for high-precision control applications.The operation principle of the prototype machine is analyzed using the finite element method(FEM),and the parameters,such as the back electromotive force(EMF) and the phase flux linkage,are calculated.The calculated and measured results reveal that the back EMF and the flux linkage are essentially sinusoidal,and the variation of the phase flux linkage profile of the LFSPM machine is similar to that of the linear surface permanent magnet(LSPM) machine.Based on this,a dynamical dq model and a simulation control model are proposed.The simulation results are compared with the test results obtained from a DSP-based control platform,which verifies that the model is correct and effective.Moreover,the model can be used for design optimization and control development. 展开更多
关键词 precision control FLUX-SWITCHING permanent magnet machine dq model vector control
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Static characteristics of a novel flux-switching permanent magnet linear motor
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作者 黄磊 余海涛 +2 位作者 胡敏强 周士贵 刘合祥 《Journal of Southeast University(English Edition)》 EI CAS 2011年第1期26-30,共5页
A novel flux-switching permanent magnet linear motor(FSPMLM) is proposed for linear direct driving machine tools.First,the two-and three-dimensional topological configuration of the proposed motor is presented;the b... A novel flux-switching permanent magnet linear motor(FSPMLM) is proposed for linear direct driving machine tools.First,the two-and three-dimensional topological configuration of the proposed motor is presented;the basic operational principle of the FSPMLM is introduced;and the magnetic fields at the two typical conditions of no-load are analyzed.Secondly,the FSPMLM is analyzed by the two-dimensional finite element method(FEM) to investigate the static electromagnetic characteristics such as flux-linkage,back EMF(electromotive force) and inductance performances.The cogging forces of two kinds of FSPMLMs with different shaped cores are analyzed and compared,and the results show that the cogging force is significantly reduced by using the E-shaped cores.Additionally,based on the co-energy method,the thrust equation is derived and verified by the simulation results obtained by the FEM.Finally,an experimental prototype is used to test the characteristics under open circuit and load conditions.The simulation and experimental results indicate that the proposed motor has advantages of a sinusoidal back-EMF waveform,a small cogging effect and a high thrust density,and it is suitable for the application of linear direct driving machine tools. 展开更多
关键词 FLUX-SWITCHING permanent magnet linear motor finite element method static characteristics
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THREE-PHASE BRIDGE INVERTER FOR 9kW DOUBLY SALIENT PERMANENT MAGNET MOTOR
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作者 黄伟君 秦海鸿 +1 位作者 王慧贞 严仰光 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第1期27-33,共7页
The three-phase bridge inverter is used as the converter topology in the power controller for a 9 kW doubly salient permanent magnet (DSPM) motor. Compared with common three-phase bridge inverters, the proposed inve... The three-phase bridge inverter is used as the converter topology in the power controller for a 9 kW doubly salient permanent magnet (DSPM) motor. Compared with common three-phase bridge inverters, the proposed inverter works under more complicated conditions with different principles for special winding back EMFs, position signals of hall sensors, and the given mode of switches. The ideal steady driving principles of the inverter for the motor are given. The working state with asymmetric winding back EMFs, inaccurate position signals of hall sensors, and the changing input voltage is analyzed. Finally, experimental results vertify that the given anal ysis is correct. 展开更多
关键词 doubly salient permanent magnet motor three-phase bridge inverter winding back EMF position signal of hall sensor input voltage
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Optimization Design and Analysis of a Hybrid Permanent Magnet Flux-Switching Motor with Compound Rotor Configuration 被引量:1
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作者 Zixuan Xiang Xiaoyong Zhu +1 位作者 Li Quan Deyang Fan 《CES Transactions on Electrical Machines and Systems》 2018年第2期200-206,共7页
This paper proposes a type of flux-switching permanent magnet(FSPM)motor,where the design concept of the hybrid permanent magnets(HPM)and the compound rotor are incorporated into the motor design.In such design,the pr... This paper proposes a type of flux-switching permanent magnet(FSPM)motor,where the design concept of the hybrid permanent magnets(HPM)and the compound rotor are incorporated into the motor design.In such design,the proposed motor can not only realize the significant reduction of NdFeB volume,but also artfully convert external magnetic flux leakage into the air-gap field to achieve competitive torque density and desirable PM usage efficiency.For extensive investigation,two topologies of the HPM are designed and analyzed for the proposed motor,which consist of the parallel-magnetic-hybrid(PMH)mode and serial-magnetic-hybrid(SMH)mode.To fully exploit the potential advantages of the proposed motor,a multi-objective optimization design is conducted,where the response surface method(RSM)and sequential non-linear programming(SNP)method are purposely utilized.After optimization,the electromagnetic performances of the motor with PMH mode and SMH mode are evaluated and compared by using finite element method(FEM),which include the back-EMF,cogging torque,output torque,and so on.Furthermore,the partial demagnetization of the ferrite PM is also investigated in the paper.Finally,the theoretical analysis and simulation study verify the effectiveness of the proposed motor and corresponding optimization design. 展开更多
关键词 Electromagnetic performances flux-switching permanent magnet(FSPM)motor hybrid permanent magnets(HPM) multi-objective optimization.
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Analysis and Modeling of Tooth-Tip Leakage Fluxes in a Radial-Flux Dual-Stator Machine with Diametrically Magnetized Cylindrical Permanent Magnets
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作者 Nejat Saed Shahin Asgari Mojtaba Mirasalim 《CES Transactions on Electrical Machines and Systems》 CSCD 2019年第4期382-388,共7页
Tooth-tip Leakage flux(TLF)has a major effect on the prediction of air-gap flux distribution and electromagnetic torque in the permanent magnet(PM)machines.Therefore,deriving a model for TLF is necessary for machine d... Tooth-tip Leakage flux(TLF)has a major effect on the prediction of air-gap flux distribution and electromagnetic torque in the permanent magnet(PM)machines.Therefore,deriving a model for TLF is necessary for machine design and optimization.Accurate modeling of TLF can lead to fast and precise solutions,which ease the analysis of electromagnetic devices.It also provides the opportunity to increase torque density by more efficient utilization of PM’s volume and prevent saturation in machine optimization.This paper presents a method for modeling and analyzing TLFs in a radial-flux dual-stator permanent magnet(DSPM)machine with diametrically magnetized cylindrical permanent magnets(DMCPM)in series and parallel magnetic circuit structures.In this model,some expressions in terms of machine dimensions are derived for the TLF analysis.Finite element method(FEM)is applied to validate the proposed model.Results indicate that the maximum error between the proposed model and FEM is insignificant(less than 6%).Finally,by a prototyped machine the validity of the proposed model was investigated with the experimental tests. 展开更多
关键词 Dual-stator permanent magnet(DSPM)machine diametrically magnetized cylindrical permanent magnet(DMCPM) tooth-tip leakage fluxes(TLFs).
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Permanent versus disconnectable FPSOs 被引量:2
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作者 罗勇 王宏伟 《Journal of Marine Science and Application》 2009年第2期93-98,共6页
Floating production storage and offioading (FPSO) vessels offer a cost-effective field development solution, especially in deepwater areas lacking an adequate pipeline network. Most FPSOs are permanently moored, i.e... Floating production storage and offioading (FPSO) vessels offer a cost-effective field development solution, especially in deepwater areas lacking an adequate pipeline network. Most FPSOs are permanently moored, i.e. the complete system is designed to withstand any kind of extreme environment at the field location. FPSOs that can be quickly disconnected from their moorings and risers have also been designed and deployed. The key feature of this type of disconnectable FPSO is that it can be disconnect and so avoid dangerous environmental conditions such as icebergs, hurricanes in the Gulf of Mexico and typhoons in the South China Sea. In this paper, the concept of disconnectable FPSOs for deepwater field development is presented. Key technologies and their engineering analyses are highlighted. The merits and demerits of disconnectable vs permanent FPSOs are then evaluated. The paper concludes that both permanent and disconnectable FPSOs are versatile floating systems and their selection depends on safety, technological, cost and operational considerations. 展开更多
关键词 disconnectable FPSO permanent FPSO DEEPWATER mooring system
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Advance in the chemical synthesis and magnetic properties of nanostructured rare-earth-based permanent magnets 被引量:13
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作者 Ce Yang Yang-Long Hou 《Rare Metals》 SCIE EI CAS CSCD 2013年第2期105-112,共8页
Rare-earth-based permanent magnets are one of the most important magnets in both scientific and industrial fields. With the development of technology, nanostructured rarearth-based permanent magnets with high energy p... Rare-earth-based permanent magnets are one of the most important magnets in both scientific and industrial fields. With the development of technology, nanostructured rarearth-based permanent magnets with high energy products are highly required. In this article, we will review the progress in chemical synthetic strategies of nanostructured rare-earth-based permanent magnets. 展开更多
关键词 RARE-EARTH permanent magnets Chemicalsynthesis
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