永磁力(能)与机械力(能)直接转换理论及永磁能发动机(磁机)

利用超强永磁体(如稀土钕铁硼等)作为唯一的能源,借助精巧设计的行星传动机构作为载体,使磁系统中的藕合磁场产生旋转动能而输出机械功,这就是新型发动机——磁机。21世纪人类将进入崭新的永磁能时代!

Modeling of Magneto-Rheological Damper with Neural Network

With the revival of magnetorheological technology research in the 1980’s, its application in vehicles is in- creasingly focused on vibration suppression. Based on the importance of magnetorheological damper modeling, non- parametric modeling with neural network, which is a promising development in semi-active online control of vehicles with MR suspension, has been carried out in this study. A two layer neural network with 7 neurons in a hidden layer and 3 inputs and 1 output was established to simulate the behavior of MR damper at different excitation currents. In the neural network modeling, the damping force is a function of displacement, velocity and the applied current. A MR damper for vehicles is fabricated and tested by MTS; the data acquired are utilized for neural network training and vali- dation. The application and validation show that the predicted forces of the neural network match well with the forces tested with a small variance, which demonstrates the effectiveness and precision of neural network modeling.

Theory and experiment of observer based magnetostrictive self-sensing actuator

Giant magnetostrictive actuators (GMAs) often work in a close-loop feedback system. This system needs independent sensors which may be difficult to be fixed, besides, excessive sensors may cause more unpredicted problems in a large system. This paper aims to develop a self-sensing GMA. An observer based on piezomagnetic equations is constructed to estimate the stress and strain of the magnetostrictive material. The observer based self-sensing approach depends on the facts that the magnetic field is controllable and that the magnetic induction is measurable. Aiming at the nonlinear hysteresis in magnetization, a hys- teresis compensation observer based on Preisach model is developed. Experiment verified the availability of the observer approach, and the hysteresis compensation observer has higher tracking precision than linear observer for dynamic force sensing.

A new controller for the semi-active suspension system with magnetorheological dampers

A new sliding mode controller for semi-active suspension system with magnetorheological (MR) damper is presented in this paper. In the proposed sliding mode controller, a semi-active suspension based on the skyhook damper system is chosen as the reference model to be followed, and the control law is so determined that the asymptotically stable error dynamics occurs between the controlled state and the reference model state. Numerical simulations are carried out to study the performance of the new sliding mode controller. The results show that the proposed controller yields almost perfect tracking to the reference model and has a high robustness against model parameter uncertainties and disturbances.

Dynamic Analysis of Micro-machined Diamagnetic Stable Permanent Magnet Levitation System

A novel micro-machined diamagnetic stable.levitation system （MDSLS） which is composed of a free permanent magnetic rotor, a ring lifting permanent magnet and two diamagnetic stabilizers was presented. The static and dynamic stable characters of MDSLS were analyzed. The coupled non-linear differential equations were used to describe six-degree-of-freedom motion of the levitated rotor, and the equivalent surface current and combined dia- magnetic image current method were utilized to model the interaction forces and torques between the lifting perma- nent magnet and rotor permanent magnet and also between the rotor permanent magnet and diamagnetic sub- strates. Because of difficulty to get analytical solution, the numerical calculation based on Runge-Kutta method was used to solve the dynamic model. The vibration frequencies were identified b~ fast Fourier transform （FFT） analysis. According to their resonance characteristics and parameters, the translational and angular dynamic stiff- ness were also calculated. The results show that the levitation of the rotor in MDSLS is stable, and the MDSLS is potential for the application in levitation inertial sensor.

Thermal Entanglement in Lipkin-Meshkov-Glick Model

We investigate the thermal entanglement in the Lipkin-Meshkov-G1ick （LMG） model which consists of spin-1/2 particles with XXZ-type exchange interactions between any pair of them. The ferromagnetic （FM） and antiferromagnetic （AFM） cases are completely analyzed at both finite temperature and zero temperature. According to the results obtained by accurate numerical calculation, several interesting physic phenomena and characteristics of thermal entanglement in the LMG model are found. Not only do we evaluate the entanglement of the LMG model, but also discover the correlations between macroscopic physical quantities and thermal entanglement.

The dynamic behavior of two collinear cracks in magneto-electro-elastic composites under harmonic anti-plane shear waves

The dynamic behavior of two collinear cracks in magneto-electro-elastic composites under harmonic anti-plane shear waves is studied using the Schmidt method for the permeable crack surface conditions. By using the Fourier transform, the problem can be solved with a set of triple integral equations in which the unknown variable is the jump of the displacements across the crack surfaces. In solving the triple integral equations, the jump of the displacements across the crack surface is expanded in a series of Jacobi polynomials. It can be obtained that the stress field is independent of the electric field and the magnetic flux.

Magnetic Properties of the Phosphorous and Carbon with a Four and Five Bonds

The authors discovered a new magnetic properties of the phosphorous and carbon with a four and five bond, and stibine, bismuthine in organometallic chemistry. This allows to modify many of classical reactions by replacing with the nitrogen atoms to atoms of phosphorus, arsenic, antimony and bismuth. The authors have proposed a new mechanism for the possible reactions.

Novel Switched Reluctance Motor with Auxiliary Winding

The characteristics of the novel switched reluctance motor with auxiliary winding and four big swallow-tailed-slots in the internal surface of stator is analysed with the stator cross section and winding photo given, and the nlathematical model of the novel switched reluctance motor presented. To show that the auxiliary winding causes the electromotive force to improve current waveform and increase output power. The different effects of auxiliary winding on system performance under different speeds are analyzed and experimented. Simulation analyzing and experiments studying of the novel switched reluctance motor demonstrate validity of auxiliary winding improving current waveforms, increasing output power.

Examples of the Teaching of the Health Questions of Electric and Magnetic Fields at Tampere University of Technology in Finland

The objective of the article is to present the examples of the teaching of the health questions of electric and magnetic fields at TUT （Tampere university of technology） in Finland. At TUT, the education of the health questions of electric and magnetic fields has been integrated into part of four courses, which also include other environmental issues. TUT also products two times per year situation report bulletins on medical-oriented studies related to electric and magnetic fields so that graduates and people working in transmission line projects can follow new studies of the area. It is important to develop more education of EMF health questions, so people can more easily understand how new devices and technologies work.

Primary Results of Liquid Metal Free Surface Jet Research

The liquid metal free surface innovation concept have been considered as liquid metal devices of divertor/limiter and tile of first wall in fusion device because it can withstand over 50 MW·m^2 heating load, is easily renewed by circulation and many overcome neutron irradiation damage life time limit. There are three types of free surface in the innovation concept as film, curtain （jets or drops） and capillary. The free surface jet is played a more attention at present. But it is no so clear and only a few available data that their magneto-hydrodynamics （MHD） instabilities, interaction with plasma and exclusion of the particles （ions, Alpha particles and so on） from liquid metal, in despite of many liquid metal free surface facilities built and operated especially in US in last two years. Recently, some primary results are carried out at LMEL facility at Southwestern Institute of Physics.

Development of a Small Scale Magnetically Levitated Train as Demonstrator for Undergraduate Mechatronics Students

At the Institute of Electrical Machines of the Rheinisch Westfalilische Technische Hochschule Aachen University, there is a project financed by student fees for the realization of a magnetically levitated train in the scale of 1：50. Undergraduate students are supposed to get the possibility to design and build up a real train which serves as demonstrator for a mechatronic system. This project strengthens the motivation of students, since a practical demonstration of electromagnetic forces is given in addition to theoretical courses. This paper introduces the major project steps and explains the learning targets for the students. It focuses on analytical magnetic circuit design, numerical field simulation, modeling and control of a multi degree of freedom system, electronic circuit design, measurement setups and a first prototype test bench.

Global well-posedness of the MHD equations via the comparison principle

In this paper,we prove the global well-posedness of the incompressible magneto-hydrodynamics(MHD)equations near a homogeneous equilibrium in the domain R^k×T^(d-k),d≥2,k≥1 by using the comparison principle and constructing the comparison function.

A microporous lanthanide metal-organic framework containing channels:Synthesis,structure,gas adsorption and magnetic properties

Under solvothermal condition,the reaction of furan-2,5-dicaboxylate(H2FDA) and glycol with Gd(NO3)3.6H2O gave microporous lanthanide metal-organic framework(MOF),{[Gd(FDA)1.5(glycol)].1.5H2O}}n(1).This compound was characterized by single crystal X-ray diffraction,infrared spectroscopy,elemental analysis,thermogravimetry analysis,and powder X-ray diffraction.The Gd(III) ions were connected by carboxylic group of FDA2-to give 1D chains,which were further linked by FDA2-,forming a 3D porous framework with 3D channels.Gas adsorption properties with N2,H2 and CO_(2) of the compound were studied.Magnetic studies show that there are weak ferromagnetic interactions transmitted by μ1,3 carboxylic group between the Gd(III) ions.

Simplified mathematical model of inter-turn short circuit of field windings in hydro-generators and its application

Inter-turn short circuit of field windings is a common electrical fault of generators.Simulation is an important method of investigating the fault and providing data support for fault monitoring.However,huge numbers of pole pairs and damper loops in large hydro-generators would lead to lengthy calculation time,hindering scientific research and engineering application.To deal with this problem,we analyze a theoretical basis for a damper winding simplified model and then propose an equivalent treatment method.Through the analysis of steady-state current harmonic characteristics of generators with different stator winding configurations during the fault,the simplified models suitable for steady-state calculation are derived from two aspects,namely,additional rotor harmonic current frequency characteristics and the relationship of the amplitude as well as the phase of each branch current of the stator.The calculation and experimental results of the two simplified models are then compared to verify the models' correctness.A calculation example of the Three Gorges left bank VGS generator shows few deviations between the calculation results of the simplified model and the original model.Moreover,the calculation time using the simplified model is 1/1500 that using the original model,which provides a more effective tool for on-line fault monitoring.Finally,the sensitivity-verification application of the fault-monitoring scheme based on the stator steady-state unbalanced current RMS is depicted.The result shows that the scheme can monitor two-turn short circuits of field windings in the Three Gorges generator and provide high sensitivity.

Performance calculation and improved model research of direct-drive permanent magnet generator based on FEM

In some control strategies of the direct-rive permanent magnet generator(DDPMG),the mathematics model is excessively simplified and some complex nonlinear characteristics,such as core saturation and cross-saturation,are generally neglected.To solve this problem,this paper utilizes the frozen element permeability method to compute the armature self-and mutual-inductance,permanent magnet d-and q-axis flux varying with d-axis and q-axis current,then an improved model is presented in which the core saturation and cross-saturation between d-axis and q-axis are considered effectively.Based on this model,the method for computing the performance of the generators is also proposed.Taking a 1.5-MW DDPMG as an example,the time-stepping finite element method(T-S FEM) is adopted to analyze the performance with no-load and loaded conditions,the results show a good agreement with the ones obtained by the improved model.Compared with the simplified model,it is demonstrated that the presented model has the high efficiency and reliability and can provide a good reference for optimization design of DDPMG and other PM motors.

Numerical simulation on magnetohydrodynamic power generation channel of scramjet

The reverse magnetohydrodynamic(MHD)energy bypass technology is a promising energy redis⁃tribution technology in the scramjet system,in augmented with a power generation equipment to supply the neces⁃sary long-distance flight airframe power.In this paper,a computational model of the scramjet magnetohydrody⁃namic channel is developed and verified by using the commercial software Fluent.It is found that when the mag⁃netic induction intensity is 1,2,3,4 T,the power generation efficiency is 22.5%,22.3%,22.0%,21.5%,and decreases with the increase of the magnetic induction intensity,and the enthalpy extraction rate is 0.026%,0.1%,0.21%,0.34%,and increases with the increase of the magnetic induction intensity.The deceleration ef⁃fect of electromagnetic action on the airflow in the power channel increases with the increase of magnetic induc⁃tion intensity.The stronger the magnetic field intensity,the more obvious the decreasing effect of fluid Mach num⁃ber in the channel.The power generation efficiency decreases as the magnetic induction intensity increases and the enthalpy extraction rate is reversed.As the local currents gathering at inlet and outlet of the power generation area,total temperature and enthalpy along the flow direction do not vary linearly,and there are maximum and minimum values at inlet and outlet.Increasing the number of electrodes can effectively regulate the percentage of Joule heat dissipation,which can improve the power generation efficiency.

Thermal entangled four-level quantum Otto heat engine

Based on a two-qubit isotropic Heisenberg XXX model with a constant external magnetic field,we construct a four-level entangled quantum heat engine(QHE).The expressions for several thermodynamic quantities such as the heat transferred,the work and efficiency are derived.Moreover,the influence of the entanglement on the thermodynamic quantities is investigated analytically and numerically.Several interesting features of the variation of the heat transferred,the work and the efficiency with the concurrences of the thermal entanglement of different thermal equilibrium states are obtained.

Nonlinear Dynamics of Permanent-magnet Synchronous Motor with v/f Control

The nonlinear dynamics of permanent-magnet synchronous motor(PMSM) with v/f control signals is investigated intensively.First,the equilibria and steady-state characteristics of the system are formulated by analytical analysis.Then,some of its basic dynamical properties,such as characteristic eigenvalues,Lyapunov exponents and phase trajectories are studied by varying the values of system parameters.It is found that when the values of the system parameters are smaller,the PMSM operates in stable domains,no matter what the values of control gains are.With the values of parameters increasing,the unstability appears and PMSM falls into chaotic operation.Furthermore,the complex dynamic behaviors are verified by means of simulation.

Blowup mechanism for viscous compressible heat-conductive magnetohydrodynamic flows in three dimensions

We investigate initial-boundary-value problem for three-dimensional magnetohydrodynamic （MHD） system of compressible viscous heat-conductive flows and the three-dimensional full compressible Navier-Stokes equations. We establish a blowup criterion only in terms of the derivative of velocity field, similar to the Beale^Kato-Majda type criterion for compressible viscous barotropic flows by Huang et al. （2011）. The results indicate that the nature of the blowup for compressible MHD models of viscous media is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model, in particular, it is independent of the temperature and magnetic field. It also reveals that the deformation tensor of the velocity field plays a more dominant role than the electromagnetic field and the temperature in regularity theory. Especially, the similar results also hold for compressible viscous heat-conductive Navier-Stokes flows, which extend the results established by Fan et al. （2010）, and I-Iuang and Li （2009）. In addition, the viscous coefficients are only restricted by the physical conditions in this paper.