检索结果-南通市图书馆

Linking discrete particle simulation to continuum process modelling for granular matter: Theory and application

在线全文

学校读者我要写书评

暂无评论

Particuology 2011年第4期9卷 342-357页

作者： H.P. zhu Z.Y. Zhou q.F. Hou A.B. Yu School of Engineering University of Western Sydney Locked Bag 1797 Penrith NSW 2751 Australia Laboratory for Simulation and Mo-delling of Particulate Systems School of Materials Science and Engineering The University of New South Wales Sydney NSW 2052 Australia

Two approaches are widely used to describe particle systems： the continuum approach at macroscopic scale and the discrete approach at particle scale. Each has its own advantages and disadvantages in the modelling of particle systems. It is of paramount significance to develop a theory to overcome the disadvantages of the two approaches. Averaging method to link the discrete to continuum approach is a potential technique to develop such a theory. This paper introduces an averaging method, including the theory and its application to the particle flow in a hopper and the particle-fluid flow in an ironmaking blast furnace.

关键词： Particle flow Gas-solid flow Discrete approach Averaging method Hopper flow Blast furnace

IN　SITULASER　RAMAN　SPECTROSCOPY　OF　THERMAL　DECOMPOSITION　OF　AMMONIUM　TUNGSTATE

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1995年第12期6卷 1085-1086页

作者： Li, XS zhu, BZ wang, L Miao, YF Xin, q Chinese Acad Sci Dalian Inst Chem Phys State Key Lab Catalysis Dalian 116023 Peoples R China Henan Coll Educ Dept Chem Zhengzhou 450003 Peoples R China

The mechanism of thermal decomposition of ammonium tungstate has been studied by to situ laser Raman spectroscopy (LRS) combined with thermal gravimetric analysis (TG), differental thermal analysis (DTA) and X-ray dif...

关键词：

Hybrid Excited Permanent Magnet Machines for Electric and Hybrid Electric Vehicles

在线全文

学校读者我要写书评

暂无评论

CES Transactions on Electrical Machines and Systems 2019年第3期3卷 233-247页

作者： Z.q.zhu S.Cai Department of Electronics and Electrical Engineering University of SheffieldSheffieldS13JD U.K

This paper reviews various hybrid excited(HE)machines from the perspective of location of PM and DC excitation,series/parallel connection of PM and DC excited magnetic fields,and 2D/3D magnetic fields,*** advantages as well as drawbacks of each category are *** an additional control degree,*** excitation,is introduced in the HE machine,the flux weakening control strategies are more *** flux weakening performance as well as efficiency are compared with different control ***,the potential to mitigate the risk of uncontrolled overvoltage fault at high speed operation is highlighted by controlling the field *** additional DC coils are usually required for HE machines compared with pure PM excitation,the spatial confliction inevitably results in electromagnetic performance ***,the technique to integrate the field and armature windings with open-winding drive circuit is introduced,and novel HE machines without a DC coil are summarized.

关键词： Electric vehicle(EV) flux weakening control hybrid electric vehicle(HEV) hybrid excited(HE)machine open-winding permanent magnet(PM).

Effects of chemical pressure on diluted magneticsemiconductor(Ba,K)(Zn,Mn)_2As_2

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第5期28卷 288-292页

作者： Y Peng S Yu G q Zhao w M Li J F Zhao L P Cao X C wang q q Liu S J Zhang R Z Yu Z Deng X H zhu C q Jin College of Materials Science & Engineering Sichuan University Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences School of Physics University of Chinese Academy of Sciences Collaborative Innovation Center of quantum Matter

Chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of Sb or P into As on a recently discovered diluted magnetic semiconductor(Ba,K)(Zn,Mn)_2 As_2, which has the record of reliable Curie temperature of 230 K due to independent charge and spin doping. Sb and P are substituted into As-site to produce negative and positive chemical pressures, respectively.X-ray diffraction results demonstrate the successful chemical solution of dopants. Magnetic properties of both K-underdoped and K-optimal-doped samples are effectively tuned by Sb-and P-doping. The Hall effect measurements do not show decrease in carrier concentrations upon Sb-and P-doping. Impressively, magnetoresistance is significantly improved from7% to 27% by only 10% P-doping, successfully extending potential application of(Ba,K)(Zn,Mn)_2 As_2.

关键词： chemical pressure (Ba,K)(Zn,Mn)2As2 diluted magnetic semiconductor iso-valent doping

Optimal Split Ratio in Small High Speed PM Machines Considering Both Stator and Rotor Loss Limitations

在线全文

学校读者我要写书评

暂无评论

CES Transactions on Electrical Machines and Systems 2019年第1期3卷 3-11页

作者： J.Ma Z.q.zhu Department of Electrical and Electronic Engineering The University of SheffieldSheffieldS13JDU.K.

The split ratio which is defined as the ratio between rotor and stator outer diameters is critical for permanent magnet(PM)*** this paper,the split ratio in small high speed PM machines is optimized analytically by considering both stator and rotor loss *** this way,the thermal constrains in both stator and rotor parts can be taken into *** shows that both losses can significantly affect the optimal split ratio and the machine *** considering the influence of rotor losses,especially the rotor eddy current loss,the optimal split ratio is increased significantly in certain *** output torque is calculated analytically and the influences of several key design parameters on the optimal split ratio,***/pole combinations and magnet materials,are also investigated in ***,finite element(FE)analyses are carried out for validating of the analytical model.

关键词： Index Terms-High speed permanent magnet split ratio.

冻结磁导率先进技术及其在高性能电机研发中的应用（英文）

在线全文

学校读者我要写书评

暂无评论

电工技术学报 2016年第20期31卷 13-29页

作者：诸自强褚文强谢菲尔德大学

如何考虑磁场饱和的影响是当前电机设计中一个亟待解决的重要问题。近年来提出的冻结磁导率技术越来越多地被应用到电机负载电磁性能和参数计算中。本文详细阐述了冻结磁导率的原理及其在各种电机中的应用现状。研究表明,冻结磁导率技... 详细信息

如何考虑磁场饱和的影响是当前电机设计中一个亟待解决的重要问题。近年来提出的冻结磁导率技术越来越多地被应用到电机负载电磁性能和参数计算中。本文详细阐述了冻结磁导率的原理及其在各种电机中的应用现状。研究表明,冻结磁导率技术可以用来精确分离各种电机负载状态下的电磁分量,如磁场、磁链、电感、转矩、转矩波动、反电势和端电压、弱磁性能以及径向力等均可以用冻结磁导率技术预测,并用来辅助电机及其驱动控制系统的设计。因此,冻结磁导率技术为高性能电机的研发提供了一个全新的方法。

关键词：电机冻结磁导率负载性能永磁

Influence of Rotor Iron Bridge Position on DC-winding-induced Voltage in wound Field Switched Flux Machine Having Partitioned Stators

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2021年第3期7卷 20-28页

作者： Zhongze wu Z.q.zhu Chao wang wei Hua Kai wang wentao Zhang School of Electrical Engineering Southeast UniversityNanjing 210096China Department of Electronic and Electrical Engineering University of SheffieldSheffield S102TNUK College of Automation Nanjing University of Aeronautics and AstronauticsNanjing 211106China

In this study,the influence of the position of the rotor iron bridge on the DC-winding-induced voltage pulsation in a partitioned stator wound field switched flux machine is *** and finite element(FE)analyses show that both the open-circuit and on-load DC-winding-induced voltages can be minimized by positioning the rotor iron bridge adjacent to the inner air gap closer to the DC *** is due to a smoother inner air-gap magnetic reluctance while maintaining the average electromagnetic torque at 92.59%of the maximum *** analyzed machine with the rotor iron bridge adjacent to the inner air gap is prototyped,and the experimental results validate the analytical and FE results.

关键词： DC winding induced voltage flux switching iron bridge partitioned stator switched flux wound field

Influence of Inner/Outer Stator Pole Ratio and Relative Position on Electromagnetic Performance of Partitioned Stator Switched Flux Permanent Magnet Machines

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CES Transactions on Electrical Machines and Systems 2019年第3期3卷 259-268页

作者： J.T.Shi Z.q.zhu Department of Electronic and Electrical Engineering The University of Sheffield3 Solly StreetSheffieldS14DEUK

Based on the 6-pole outer stator(armature winding-stator),the influence of inner(permanent magnet-stator)/outer stator pole ratio n(n=NIS/NOS),stator relative positions and rotor pole number combinations on electromagnetic performance of partitioned stator switched flux permanent magnet(PM)machines(PS-SFPMMs)is investigated in this *** the armature windings and PMs are located in two separated stators and PMs are stationary,PS-SFPMMs have high fault tolerance *** maximize the torque performance,the PM of inner stator pole should be aligned with outer stator pole when n is odd while the iron rib of inner stator pole should be aligned with outer stator pole when n is *** matter what n is selected,the rotor pole number NR can be any integers except the phase number and its *** analysis results indicate that the optimal NR is closed to(NIS+NOS)/2 and it is odd when n is odd while it is even when n is ***,symmetrical phase back-EMF waveform will be obtained when the ratio of Min(NOS,NIS)to the greatest common divisor of Min(NOS,NIS)and NR is *** on the optimal rotor pole numbers for 6-pole outer stator with different n and corresponding optimal relative position together with same rated copper loss,the average torque is improved by 18.4%,25.1%and 25.7%respectively in PS-SFPMMs with n equal to 2,3 and 4 when compared with PS-SFPMM with n equal to *** analyses are validated by experiment results of the prototype machine.

关键词： Inner/outer stator partitioned stator permanent magnet pole ratio relative position switched flux.

Current diffusion and efficiency droop in vertical light emitting diodes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第1期28卷 561-569页

作者： R q wan T Li Z q Liu X Y Yi J X wang J H Li w H zhu J M Li L C wang State Key Laboratory of High Performance Complex Manufacturing College of Mechanical and Electrical EngineeringCentral South University Semiconductor Lighting Technology Research and Development Center Institute of SemiconductorsChinese Academy of Sciences College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences

Current diffusion is an old issue, nevertheless, the relationship between the current diffusion and the efficiency of light emitting diodes(LEDs) needs to be further quantitatively clarified. By incorporating current crowding effect(CCE) into the conventional ABC model, we have theoretically and directly correlated the current diffusion and the internal quantum efficiency(IqE), light extraction efficiency(LEE), and external quantum efficiency(EqE) droop of the lateral ***, questions still exist for the vertical LEDs(V-LEDs). Here firstly the current diffusion length L_s(I) and L_s(II) have been clarified. Based on this, the influence of CCE on the EqE, IqE, and LEE of V-LEDs were investigated. Specifically to our V-LEDs with moderate series resistivity, L_s(III) was developed by combining L_s(I) and L_s(II), and the CCE effect on the performance of V-LEDs was investigated. The wall-plug efficiency(wPE) of V-LEDs ware investigated finally. Our works provide a deep understanding of the current diffusion status and the correlated efficiency droop in V-LEDs, thus would benefit the V-LEDs' chip design and further efficiency improvement.

关键词： efficiency droop vertical light emitting diodes current crowding effect current blocking layer