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Gyrokinetic simulation of magnetic-island-induced electric potential vortex mode
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作者 王丰 李继全 +1 位作者 曲洪鹏 彭晓东 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第1期34-41,共8页
Ion temperature gradient(ITG)-driven turbulence with embedded static magnetic islands is simulated by utilizing a gyrokinetic theory-based global turbulence transport code(GKNET)in this work.Different from the traditi... Ion temperature gradient(ITG)-driven turbulence with embedded static magnetic islands is simulated by utilizing a gyrokinetic theory-based global turbulence transport code(GKNET)in this work.Different from the traditional equilibrium circular magnetic-surface average(EMSA)method,an advanced algorithm that calculates the perturbed magnetic-surface average(PMSA)of the electric potential has been developed to precisely deal with the zonal flow component in a non-circular magnetic surface perturbed by magnetic islands.Simulations show that the electric potential vortex structure inside islands induced by the magnetic islands is usually of odd parity when using the EMSA method.It is found that the odd symmetry vortex can transfer into an even one after a steep zonal flow gradient,i.e.the flow shear has been built in the vicinity of the magnetic islands by adopting the PMSA algorithm.The phase of the potential vortex in the poloidal cross section is coupled with the zonal flow shear.Such an electric potential vortex mode may be of essential importance in wide topics,such as the turbulence spreading across magnetic islands,neoclassical tearing mode physics,and also the interaction dynamics between the micro-turbulence and MHD activities. 展开更多
关键词 magnetic islands electric vortex ITG perturbed magnetic flux surface average
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Binding energy of the donor impurities in GaAs-Ga_(1-x)Al_xAs quantum well wires with Morse potential in the presence of electric and magnetic fields
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作者 Esra Aciksoz Orhan Bayrak Asim Soylu 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第10期39-44,共6页
The behavior of a donor in the GaAs–GaAlAs quantum well wire represented by the Morse potential is examined within the framework of the effective-mass approximation. The donor binding energies are numerically calcula... The behavior of a donor in the GaAs–GaAlAs quantum well wire represented by the Morse potential is examined within the framework of the effective-mass approximation. The donor binding energies are numerically calculated for with and without the electric and magnetic fields in order to show their influence on the binding energies. Moreover, how the donor binding energies change for the constant potential parameters(De, re, and a) as well as with the different values of the electric and magnetic field strengths is determined. It is found that the donor binding energy is highly dependent on the external electric and magnetic fields as well as parameters of the Morse potential. 展开更多
关键词 Morse potential electric field magnetic field the donor atom quantum well wire
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Electric Potential in Surface Produced Negative Ion Source with Magnetic Field Increasing Toward a Wall
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作者 Azusa FUKANO Akiyoshi HATAYAMA 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第3期266-270,共5页
Electric potential near a wall for plasma with the surface produced negative ions with magnetic field increasing toward a wall is investigated analytically. The potential profile is derived analytically by using a pla... Electric potential near a wall for plasma with the surface produced negative ions with magnetic field increasing toward a wall is investigated analytically. The potential profile is derived analytically by using a plasma-sheath equation, where negative ions produced on the plasma grid (PG) surface are considered in addition to positive ions and electrons. The potential profile depends on the amount and the temperature of the surface produced negative ions and the profile of the magnetic field. The negative potential peak is formed in the sheath region near the PG surface for the case of strong surface production of negative ions or low temperature negative ions. As the increase rate of the magnetic field near the wall becomes large, the negative potential peak becomes small. 展开更多
关键词 negative ion source surface produced negative ion sheath potential cusp magnetic field electric potential plasma-sheath equation extraction region
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Transport and Conductance in Fibonacci Graphene Superlattices with Electric and Magnetic Potentials
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作者 尹贻恒 牛燕雄 +2 位作者 丁铭 刘海月 梁振江 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第5期88-91,共4页
We investigate the electron transport and conductance properties in Fibonacci quasi-periodic graphene superlat- rices with electrostatic barriers and magnetic vector potentials. It is found that a new Dirac point appe... We investigate the electron transport and conductance properties in Fibonacci quasi-periodic graphene superlat- rices with electrostatic barriers and magnetic vector potentials. It is found that a new Dirac point appears in the band structure of graphene superlattice and the position of the Dirac point is exactly located at the energy corresponding to the zero-averaged w^ve number. The magnetic and eleetr/c potentials modify the energy band structure and transmission spectrum in entirely diverse ways. In addition, the angular-dependent transmission is blocked by the potential barriers at certain incident angles due to the appearance of the evanescent states. The effects of lattice constants and different potentials on angular-averaged conductance are also discussed. 展开更多
关键词 of on with in Transport and Conductance in Fibonacci Graphene Superlattices with electric and magnetic potentials
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“Electrical” and “Magnetic” Worlds in Universe 被引量:1
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作者 Robert A. Sizov 《Journal of Modern Physics》 2017年第7期1072-1086,共15页
Magnetic spinor particles (magnetic charges), which are the direct sources of all magnetic fields and magnetic manifestations in Nature, were experimentally discovered by the author in the structures of atoms and subs... Magnetic spinor particles (magnetic charges), which are the direct sources of all magnetic fields and magnetic manifestations in Nature, were experimentally discovered by the author in the structures of atoms and substance. The main reasons that the real magnetic charges were “buried alive” in modern theoretical concepts are the Physics their of confinement in the structures of substance, which is cardinally different from the confinement of electrons, as well as electromagnetic concept of Maxwell, in which magnetic field was erroneously deprived of its own source, i.е. of magnetic pole or magnetic charge. Magnetic and electric charges form atomic shells, which are electromagnetic, and not electronic, as is commonly assumed in the existing physical theory. Namely, the magnetic and electric charges in the joint physical processes form all the varieties of the physical mass, i.е. atoms, nucleons, substance and others. The main feature of physical mass is its ability to radiate gravitational field, which in reality is of the vortex electromagnetic field. The immediate sources of gravitational field are joint orbital currents of electric and magnetic charges in compositions of atomic shells. In 2008 the author for the first time introduced the concepts of “electric” and “magnetic” worlds. So, in the “magnetic” world the processes of condensing all elementary varieties of physical mass: atoms, nucleons and others are initiated not by electric charges as in our “electric” world, but by means of magnetic charges. Electric and magnetic charges in the compositions of physical mass, in differently charged worlds are changing their functional roles and, for example, detect electrons in the “magnetic” world also difficult as the magnetic charges in our of “electric” world. According to conceptions of the author and in our Universe existence of both “electric” so and “magnetic” masses, including charged differently of biological masses is quite possible. It is impossible to exclude and the existence of otherwise “charged” living organisms and even “electrical” and “magnetic” anthropoid beings. The latter allows to assume perhaps the existence of the differently “charged” civilizations and in our Universe. 展开更多
关键词 magnetic and electric SPINOR Particles (Spinors and Antispinors) Antielectrons magnetons Antimagnetons Bispinors Physical Mass vortex electromagnetic (Gravitational) Field electric and magnetic WORLDS
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Research on the Static Magnetic Field of Ships with Corrosion and Anticorrosion Efficacy Using Electric Dipole Model
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作者 陈聪 李定国 龚沈光 《Defence Technology(防务技术)》 SCIE EI CAS 2010年第2期133-139,共7页
In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the m... In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the mirror image theory.Combined with the distribution of the underwater electric potential measured in laboratory,an electric dipole model for physical scale of ship was established and the distribution characteristics of an actual ship' s corrosion related magnetic field were obtained.Based on established models,theoretical analysis and calculation were made to catch out the distribution characteristics of static magnetic field related with corrosion and anticorrosion,which can not be measured directly in seawater.The results show that the static magnetic field related with corrosion and anticorrosion is a kind of noteworthy obstacle signal for degaussed ships. 展开更多
关键词 weaponry engineering corrosion related magnetic field static electric field underwater electric potential mirror image theory electric dipole model
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Off-axis electron holography of manganite-based heterojunctions:Interface potential and charge distribution
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作者 Zhi-Bin Ling Gui-Ju Liu +2 位作者 Cheng-Peng Yang Wen-Shuang Liang Yi-Qian Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第4期269-274,共6页
The interfacial electrical potentials and charge distributions of two manganite-based heterojunctions, i.e.,La_(0.67)Ca_(0.33)MnO_3/SrTiO_3:0.05 wt% Nb(LCMO/STON) and La_(0.67)Ca_(0.33)MnO_3/LaMnO_3/SrTiO_3:0.05 wt% N... The interfacial electrical potentials and charge distributions of two manganite-based heterojunctions, i.e.,La_(0.67)Ca_(0.33)MnO_3/SrTiO_3:0.05 wt% Nb(LCMO/STON) and La_(0.67)Ca_(0.33)MnO_3/LaMnO_3/SrTiO_3:0.05 wt% Nb(simplified as LCMO/LMO/STON), are studied by means of off-axis electron holography in a transmission electron microscope.The influences of buffer layer on the microstructure and magnetic properties of the LCMO films are explored. The results show that when a buffer layer of LaMnO_3 is introduced, the tensile strain between the STON substrate and LCMO film reduces, misfit dislocation density decreases near the interfaces of the heterojunctions, and a positive magnetoresistance is observed. For the LCMO/STON junction, positive and negative charges accumulate near the interface between the substrate and the film. For the LCMO/LMO/STON junction, a complex charge distribution takes place across the interface, where notable negative charges accumulate. The difference between the charge distributions near the interface may shed light on the observed generation of positive magnetoresistance in the junction with a buffer layer. 展开更多
关键词 LA0.67CA0.33MNO3 films electron HOLOGRAPHY magnetic properties INTERFACIAL electrical potential charge distribution
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The Magnetic Longitudinal (P-) Wave’s Propagation and Energy Models Underlying the Mechanisms of Its Capacity to Absorb Free Energy 被引量:3
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作者 Jianzhong Jiang Yufeng Wang 《Journal of Power and Energy Engineering》 2024年第7期39-62,共24页
The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagn... The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagnetic (LEM) waves. The revised Maxwell’s equations include the crucial parameters being the attenuation time constants of magnetic vortex potential and electric vortex potential generated by external electromagnetic field within the propagation medium. Specific expressions for them are obtained through theoretical analysis. Subsequently, a model for propagating magnetic P-wave generated by the superposition of a left-handed photo and a right-handed photon in a vacuum is formulated based on reevaluated total current law and revised Faraday’s law, covering wave equations, energy equation, as well as propagation mode involving mutual induction and conversion between scalar magnetic field and vortex electric field. Furthermore, through theoretical derivations centered around magnetic P-wave, evidence was presented regarding its ability to absorb huge free energy through the entangled interaction between zero-point vacuum energy field and the torsion field produced by the vortex electric field. 展开更多
关键词 QED (Quantum electrodynamics) Energy Wave and TEM (Transverse electromagnetic) Wave magnetic P-Wave Modified Faraday’s Law of electromagnetic Induction electric/magnetic vortex potential Zero-Point Vacuum Energy
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How to Determine a Jump in Energy Prior to a Causal Barrier, with an Attendant Current, for an Effective Initial Magnetic Field. In the Pre Planckian to Planckian Space-Time 被引量:1
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作者 Andrew Walcott Beckwith 《Journal of High Energy Physics, Gravitation and Cosmology》 2018年第2期323-353,共31页
We start where we use an inflaton value due to use of a scale factor . Also we use as the variation of the time component of the metric tensor in Pre-Planckian space-time. Our objective is to find an effective magneti... We start where we use an inflaton value due to use of a scale factor . Also we use as the variation of the time component of the metric tensor in Pre-Planckian space-time. Our objective is to find an effective magnetic field, to obtain the minimum scale factor in line with Non Linear Electrodynamics as given by Camara, et al., 2004. Our suggestion is based upon a new procedure for an effective current based upon an inflaton time exp (i times (frequency) times (cosmological time)) factor as a new rescaled inflaton which is then placed right into a Noether Current scalar field expression as given by Peskins, 1995. This is before the Causal surface with which is, right next to a quantum bounce, determined by , with the next shift in the Hubble parameter as set up to be then . And is an initial degree of freedom value of about 110. Upon calculation of the current, and a resulting magnetic field, for the space time bubble, we then next obtain a shift in energy, leading to a transition from too. We argue then that the delineation of the term is a precursor to filling in information as to the Weyl Tensor for near singularity measurements of starting space-time. Furthermore, as evidenced in Equations ((26) and (27)) of this document, we focus upon a “first order” that checks into if a cosmological “constant” would be invariant in time, or would be along the trajectory of the time, varying Quinessence models. We close this document, with Maxwell equations as to Post Newtonian theory, for Gravity, with our candidates as to a magnetic field included in, with what we think this pertains to, as far as Gravo Electric and Gravo Magnetic fields, and then make suggestions as to a quantum version of this methodology for future gravitational wave physics research. This is Appendix G, this last topic, and deliberately set up future works paradigm which will be investigated in the coming year. It is based upon a Gravo Electric potential, and we make suggestions as to its upgrade in our future works, in early universe cosmology. In the reference by Poisson, and Will, they write and in this last section we come up with a value of U, based in part on the comparison with the alteration of velocity, due to a massive graviton, namely via the substitution, we write as , so as to come up with a post Newtonian approximation result for a magnetic field. We compare this magnetic field, as far as the Inflaton magnetic field, and use it to come up with observations with regards to the phenomenology of gravity in Pre Planckian to Planckian regime limits. We close, then with the observation given in Appendix H, of the inhomogeneity of Pre Planckian-to Planckian space time as a necessary condition for a Gravi-Magnetic field. We also reference an Appendix I, which does a summary of a 5th force calculation, and we then compare those results, with our temporary results of a Gravi Magneitc field, as we have tried to start up as a future works project. 展开更多
关键词 INFLATON Physics CAUSAL Structure Penrose WEYL Tensor Conjecture Quinessence Gravo electric potential Gravo electric and Gravo magnetic Fields
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Nuclear Physics with Magnetic Charges 被引量:1
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作者 Robert A. Sizov 《Journal of Modern Physics》 2018年第2期145-171,共27页
The magnetic spinor particles (magnetic charges) are the real structural components all varieties of the Mass, for example, atoms, nucleons, positrons and neutrinos. Atomic-shaped device of Mass is the natural and the... The magnetic spinor particles (magnetic charges) are the real structural components all varieties of the Mass, for example, atoms, nucleons, positrons and neutrinos. Atomic-shaped device of Mass is the natural and the only possible organization of electric and magnetic charges which can create a gravitational field. At level of a popular language one can define nucleons as “small atoms”, and positron and neutrino as “very small atoms”. The electric and magnetic fundamental particles in neutron and proton shells which by tradition should be called quarks have charges of smaller magnitude than the charges of particles in atomic shells. Positron which participates in the gravitational interaction and, consequently, has an atomic-shaped device is the most likely candidate for the role of the proton nucleus. The most likely candidate particles on the participation in nuclei of proton and neutron as well as in nuclei of the positron and neutrino are presented in the article. So-called abnormal magnetic moment of neutron is formed by the quark magnetic dipoles which are like to unpaired electrons in the so-called magnetic atoms rotate on the outer orbitals of the neutron shell. The participation of the “magnetic electron” (magneton) in the neutrino core assumes the existence of the so-called anomalous magnetic moment and in the neutrino shell. The existence of real magnetic charges in the structures of the Mass draws our attention on such important problem as interaction between charges in the framework of electromagnetic dipoles such as and in which manifest the weak attraction. Weak interaction by its nature is electromagnetic. So-called electromagnetic interaction, manifested in pairs of homogeneous charges of opposite signs, is either electric or magnetic, but not electromagnetic. The explanation of the weak interaction in the marked pairs of charges is based on the author’s concept of the World Physical Triad and “Dark Energy”. Forces responsible for the interaction of the charges composing the electromagnetic dipoles correspond, conditionally of the weak charges of the particles which what assume mutual suppression of the influence of their fields on the Energo-medium and the formation of the weak “Dark energy”. Complex of magnetic particles, the quark magnetic dipoles and magneton by means of which the interconversion of a proton and a neutron is realized and maintained their constant number in the atomic nuclei can be called as magnetic meson. Namely, a processes of interconversion between a neutron and a proton which, as a rule, are not accompanied by secretions, created the illusion of neutron stability in atomic nuclei. The energy created by an exchange of magnetic mesons between neutron and proton can be a component of nuclear forces (strong interaction). Another effective and, most likely, the main component in the composition of the nuclear forces is the gravitational “Dark Energy”. Physics and structure of neutrinos presented in the paper suggest that the nature of these particles closer to the ideology of E. Majorana than P. Dirac’s. 展开更多
关键词 magnetic and electric CHARGES Antielectrons magnetons Antimagnetons Bispinor Physical Mass vortex electromagnetic (Gravitational) Field QUARKS PROTONS Neutrons Positrons NEUTRINO MESONS Weak and Strong Interactions “Dark Energy”
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Photon Structure and Wave Function from the Vector Potential Quantization
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作者 Constantin Meis 《Journal of Modern Physics》 CAS 2023年第3期311-329,共19页
A photon structure is advanced based on the experimental evidence and the vector potential quantization at a single photon level. It is shown that the photon is neither a point particle nor an infinite wave but behave... A photon structure is advanced based on the experimental evidence and the vector potential quantization at a single photon level. It is shown that the photon is neither a point particle nor an infinite wave but behaves rather like a local “wave-corpuscle” extended over a wavelength, occupying a minimum quantization volume and guided by a non-local vector potential real wave function. The quantized vector potential oscillates over a wavelength with circular left or right polarization giving birth to orthogonal magnetic and electric fields whose amplitudes are proportional to the square of the frequency. The energy  and momentum are carried by the local wave-corpuscle guided by the non-local vector potential wave function suitably normalized. 展开更多
关键词 PHOTONS Photon Wave Function Vector potential Quantization Photon electric and magnetic Fields Photon Structure Wave-Corpuscle Representation Photon “Energy-Vector potential Equation
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Dynamics of A Rotor Supported on Magnet-Rheological Fluid Squeeze Film Damper 被引量:6
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作者 祝长生 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2001年第1期6-12,共7页
Using special characteristics of magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its viscosity by an external magnetic field, a novel controllable magneto-rheological fluid squeeze film da... Using special characteristics of magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its viscosity by an external magnetic field, a novel controllable magneto-rheological fluid squeeze film damper is presented in this paper. After analyzing the effects of the MR fluid, the externally applied magnetic flux density and the radial clearance of the damper on the behavior of a flexible rotor supported on the MR fluid squeeze film damper in the non-rotating state, an experimental study is carried out on the controllability and effectiveness of the MR fluid squeeze film damper on the rotor vibration in the rotating state. The existing problems in the MR fluid squeeze film damper, such as unbalanced magnetic pull force, and MR fluid sediment, which may result in the failure of the MR fluid squeeze film damper application, are also discussed. It is shown that not only can the dynamical characteristics of the MR fluid squeeze film damper be controlled by a simple external magnetic field, but also the applied voltage required to dramatically change the dynamic characteristics of the MR fluid squeeze film damper is much lower. The MR fluid squeeze film damper is a very effective way to control the vibration of a rotor system. 展开更多
关键词 DAMPING electric potential magnetic field effects magnetic flux Vibration control VISCOSITY
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Mathematical Wave Functions and 3D Finite Element Modelling of the Electron and Positron
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作者 Declan Traill 《Journal of Applied Mathematics and Physics》 2024年第4期1134-1162,共29页
The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric an... The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles. 展开更多
关键词 electrON POSITRON Wave Function Solution electromagnetic Spin Mass Charge Proof Fundamental Particle Properties Quantum Mechanics Classical Physics Computer 3D Model Schrödinger Equation RMS KLEIN GORDON electric magnetic Lorentz Invariant Hertzian Vector Point potential Field Density Phase Flow Attraction REPULSION Shell Theorem Ehrenfest VIRIAL Normalization Harmonic Oscillator
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运动磁体感应电场特性分析
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作者 刘瑞杰 张伽伟 谢涛涛 《兵工学报》 北大核心 2025年第5期193-200,共8页
为分析运动磁性物体产生的感应电场,改进现有模型的不足,提出一种更适用于任意方向运动的目标感应电场计算模型。对比现有运动磁体感应电场模型的适用范围及局限性,以磁偶极子的矢量磁位模型为理论基础,推导出运动磁体感应电场的数学模... 为分析运动磁性物体产生的感应电场,改进现有模型的不足,提出一种更适用于任意方向运动的目标感应电场计算模型。对比现有运动磁体感应电场模型的适用范围及局限性,以磁偶极子的矢量磁位模型为理论基础,推导出运动磁体感应电场的数学模型。通过理论分析和仿真计算验证该模型的适用性,并结合实船磁场特性进行实例计算。理论分析和仿真计算结果表明,该模型适用于沿任意方向运动的磁性物体感应电场计算,且其推导和计算过程较基于库伦定律和毕奥-萨伐定律的传统模型更为简洁。实例计算结果表明,磁性船舶运动产生的感应电场具有明显的区域特性,电场强度量级可达mV/m,是船舶静电场的重要组成部分。新提出的感应电场模型为运动磁性物体的电场探测提供了更准确的理论支持,可有效应用于船舶电场的探测与分析。 展开更多
关键词 运动磁性物体 磁偶极子 感应电场 矢量磁位 船舶 静电场
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考虑变频器特性的变速恒频双馈风力发电机组控制策略的研究与仿真 被引量:43
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作者 李晶 宋家骅 王伟胜 《电网技术》 EI CSCD 北大核心 2004年第21期11-16,共6页
以并网型变速恒频风电机组中双馈发电机的运行特性及连接于发电机转子部分的脉宽调制(PWM)控制的电压源型交—直—交变频器的结构和机理为基础,在假设变频器采用理想开关器件,即忽略电子器件的换相重叠、损耗,并只考虑变频器直流电容充... 以并网型变速恒频风电机组中双馈发电机的运行特性及连接于发电机转子部分的脉宽调制(PWM)控制的电压源型交—直—交变频器的结构和机理为基础,在假设变频器采用理想开关器件,即忽略电子器件的换相重叠、损耗,并只考虑变频器直流电容充放电的动态过程而不计频率调节的动态变化过程的前提下,提出了基于定子磁场旋转坐标系统下的变速恒频风电机组电气控制部分的控制策略并设计了相应的 PI控制器。同时基于 MATLAB 软件建立了变速恒频双馈风力发电机组的仿真模型,并以渐变风和随机风模式为例,针对提出的控制策略对变速恒频双馈风力发电机组的并网运行特性进行了仿真研究,仿真结果表明了该控制策略的合理性及控制器设计的有效性,同时也说明了双馈发电机在保证有功输出的情况下能够有效地调节无功功率,保证变速恒频风电机组的稳定运行。 展开更多
关键词 变速恒频 双馈风力发电机 风电机组 双馈发电机 变频器 定子磁场 并网运行 仿真结果 脉宽调制(PWM) 控制器设计
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岩石受压破裂的ULF和LF电磁前兆信号 被引量:39
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作者 钱书清 郝锦绮 +1 位作者 周建国 高金田 《中国地震》 CSCD 北大核心 2003年第2期109-116,共8页
实验观测到了 4类岩性、18块样品在单轴压力下直至破裂发生全过程中的ULF和LF电磁前兆信号。这些不同频率的信号是零散出现的 ,其形态为一组组脉冲 ,宽度为 4ms~16ms ,幅度为 0 1mV~ 1 4mV。实验发现具同一谐振频率的天线收到的信号... 实验观测到了 4类岩性、18块样品在单轴压力下直至破裂发生全过程中的ULF和LF电磁前兆信号。这些不同频率的信号是零散出现的 ,其形态为一组组脉冲 ,宽度为 4ms~16ms ,幅度为 0 1mV~ 1 4mV。实验发现具同一谐振频率的天线收到的信号频次与其相对于裂缝的位置和方位有关。结果还表明 ,电磁前兆信号的频度与岩样强度有关 ,抗压强度高的岩样电磁前兆信号多。微破裂可能产生了偶电层 ,在破裂过程中向外辐射 ,产生了LF频段的磁信号 ,ULF磁信号则主要由压磁效应产生。 展开更多
关键词 岩石破裂 ULF频段 LF频段 自电位 磁信号 电磁前兆信号
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深海中潜艇腐蚀相关磁场全空间分布特征分析 被引量:5
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作者 陈聪 李定国 +1 位作者 蒋治国 龚沈光 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2014年第6期684-689,共6页
为分析深海中潜艇腐蚀相关磁场的分布特征,采用静态电偶极子对场源进行模拟,采用空气-海水2层模型对深海环境进行模拟,在利用镜像法求出全空间标量电位分布的基础上,利用标量电位和矢量磁位之间的约束关系,求解得到全空间中腐蚀或防腐... 为分析深海中潜艇腐蚀相关磁场的分布特征,采用静态电偶极子对场源进行模拟,采用空气-海水2层模型对深海环境进行模拟,在利用镜像法求出全空间标量电位分布的基础上,利用标量电位和矢量磁位之间的约束关系,求解得到全空间中腐蚀或防腐电流所产生的磁场分布,并证明所得场分布是满足场方程及边界条件的。最后采用数值计算的方法对磁场空间分布特征进行了分析,结果表明:深海中的潜艇由于腐蚀及防腐措施在空气及海水中激发的静态磁场分布特征明显,是值得重视的探测或打击信号源。特别是场分量按距离的平方反比衰减,相对于铁磁材料所产生的磁场衰减要慢,有利于远程探测。研究结果为进一步的实际应用奠定了基础。 展开更多
关键词 静态水平电偶极子 深海模型 腐蚀相关磁场 矢量磁位 标量电位
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大鼠经颅磁及电刺激运动诱发电位波幅及潜伏期特征的研究 被引量:5
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作者 余科炜 李家顺 +5 位作者 贾连顺 袁文 胡玉华 石志才 戴伯军 何海龙 《第二军医大学学报》 CAS CSCD 北大核心 2000年第7期625-628,共4页
目的 :比较磁刺激运动诱发电位 ( MEP)与电刺激 MEP在刺激方式、信号特征和临床意义等方面的异同。方法 :2 0只雄性 SD大鼠经静脉麻醉后采用 Mag2型磁刺激仪和 Cantada型肌电图仪分别进行单次经颅磁及电刺激 ,观察不同刺激强度下 ,在 T1... 目的 :比较磁刺激运动诱发电位 ( MEP)与电刺激 MEP在刺激方式、信号特征和临床意义等方面的异同。方法 :2 0只雄性 SD大鼠经静脉麻醉后采用 Mag2型磁刺激仪和 Cantada型肌电图仪分别进行单次经颅磁及电刺激 ,观察不同刺激强度下 ,在 T1 2 硬膜外和双侧前肢伸肌和后肢腓肠肌记录的 MEP变化特征。结果 :磁刺激脊髓 MEP先正后负 ,以 P1 或 N1 波最显著 ,波形不够稳定 ,个体间差异较大 ,随着刺激强度增大 ,MEP潜伏期缩短 ,波幅增大。近阈值电刺激 MEP与相应的超强磁刺激 MEP潜伏期相近 ,波幅也相差不大。结论 :采用单次磁或电刺激 MEP仍能客观反映脊髓运动传导束的功能状态 ,电和磁刺激的 MEP之间存在一定程度的同源成分 。 展开更多
关键词 运动诱发电位 磁刺激 电刺激 脊髓 大鼠
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高速电气化铁路负序和谐波统一治理方法 被引量:12
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作者 张志文 黄际元 +2 位作者 罗隆福 常敏 李欣然 《电机与控制学报》 EI CSCD 北大核心 2013年第8期22-29,共8页
针对高速电气化铁路牵引供电系统中的负序、谐波等电能质量问题,提出一种基于变压器感应滤波技术的负序和谐波统一治理方法。该方法利用安匝平衡原理,将感应滤波技术和静止无功发生器(SVG)系统结合起来,前者用于滤除特征次谐波,后者用... 针对高速电气化铁路牵引供电系统中的负序、谐波等电能质量问题,提出一种基于变压器感应滤波技术的负序和谐波统一治理方法。该方法利用安匝平衡原理,将感应滤波技术和静止无功发生器(SVG)系统结合起来,前者用于滤除特征次谐波,后者用于补偿负序与残余谐波电流在此基础上,进一步开发了能快速单独检测出基波负序和任意次谐波电流的检测算法。仿真结果表明:所提出的统一治理方法及检测算法的结合可以消除变压器内部负序和谐波磁势,从而使网侧中不合有相应的负序与谐波电流。基于变压器感应滤波技术的治理方案,充分发掘了变压器的潜能和现代电力电子技术的优势,能以较低的成本和较好的效果进行负序电流补偿和谐波抑制。 展开更多
关键词 电气化铁路 变压器 感应滤波 安匝平衡原理 负序和谐波磁势
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功能性电刺激对健康青年受试者体感及运动诱发电位影响的对照研究 被引量:5
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作者 刘非 刘慧华 +1 位作者 燕铁斌 陈月桂 《中国康复医学杂志》 CAS CSCD 北大核心 2009年第9期790-792,共3页
目的:观察功能性电刺激(FES)对健康青年体感诱发电位(SEP)及运动诱发电位(MEP)的影响。方法:采用经颅磁刺激仪(TMS)及肌电图仪,分别测量15例健康青年,其中男10例,女5例,平均年龄(22.9±0.7)岁。单次FES前、后检测SEP值及MEP值,其中1... 目的:观察功能性电刺激(FES)对健康青年体感诱发电位(SEP)及运动诱发电位(MEP)的影响。方法:采用经颅磁刺激仪(TMS)及肌电图仪,分别测量15例健康青年,其中男10例,女5例,平均年龄(22.9±0.7)岁。单次FES前、后检测SEP值及MEP值,其中11例完成两周FES(每天1次,每次30min),并再次接受SEP及MEP检测。结果:健康青年者单次及2周FES后SEP及MEP值的潜伏期缩短,波幅增高,与FES前比较,差异有显著性意义;非FES侧变化不明显。结论:健康青年者FES前后SEP及MEP值均有变化,尤以波幅明显。 展开更多
关键词 功能性电刺激 体感诱发电位 运动诱发电位 磁刺激
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