• Title/Summary/Keyword: Transverse magnetic field

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Light-Output Characteristics of a Low-Pressure Mercury-Argon Discharge Lamp in a Transverse Magnetic Field (횡자계 인가시 저압 수은-아르곤 방전등의 광출력특성)

  • 여인선;박왕렬
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1989.10a
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    • pp.9-12
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    • 1989
  • ABSTRACT -- Recently, a method of magnetically-enhanced discharge columns is considered to increase the luminous efficacy of discharge lamps, which is based upon the face that the diffusion motion of charged particles in the discharge column strongly depends on the applied magnetic fields. This study investigates the effect of applied transverse magnetic fields on the light output of low-pressure Hg-Ar discharge. As a result, it is found that the electric field in the positive column increases according to the applied megnetic field, which causes an increase in the total light output. And this effect is much more pronounced upon the spectral line originating form the higher levels.

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Heat Treatment Effects of $Fe_{73.0}Cu{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$Alloy with Imbedded Nanocrystalline Phase under Magnetic Field (초미세결정립과 비정질이 공존하는 $Fe_{73.9}$$Cu_{1.0}$$Nb_{3.5}$$Si_{14.0}$$B_{7.6}$ 합금의 자기장 중 열처리)

  • Yang, J.S.;Son, D.;Cho, Y.
    • Journal of the Korean Magnetics Society
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    • v.8 no.1
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    • pp.13-20
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    • 1998
  • The crystallographic and high frequency characteristics of $Fe_{73.9}Cu_{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$ soft magnetic alloys were investigated under the magnetic field annealing. As-cast ribbon with which already imbedded nanocrystalline Fe-Si phase on the surface have a preferred orientation with (400) plane to surface and also with the [011] direction parallel to the ribbon length. The extra nanocrystalline Fe-Si phase appeared throughout at 45$0^{\circ}C$ in samples with or without the longitudinal magnetic field. However the formation of nanocrystalline phase does not appear on the suface layer until 50$0^{\circ}C$ annealing temperature under the transverse field. The cryststallization fraction of annealed samples with longitudinal magnetic field is higher than that of samples without magnetic field. When the transverse magnetic field is applied, the crystallization fraction does not increases but decreases until 50$0^{\circ}C$. However the crystallization of internal regions can be confirmed by X-ray diffraction measurement via tilting the sample. It was found that for all samples, the saturation induction were all same with 1.3 T. The coercive field of as-cast sample was 1.06 A/cm, but in annealed samples it decrease from 0.56 to 0.1 A/cm with increasing annealing temperature from 400 and 55$0^{\circ}C$, respectively. The squareness of annealed samples under transverse magnetic field has a small value than that of both without field and with longitudinal field annealing.

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Dynamic Characteristic of Magnetic Fluids in a Circular Pipe (원관내 자성유체의 동적특성)

  • 유신오;박정우;최병호;서이수
    • Journal of the Korean Magnetics Society
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    • v.10 no.1
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    • pp.42-47
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    • 2000
  • In the present work, we analyze theoretically the flow of magnetic fluids in a circular pipe with longitudinal magnetic field. We used governing equations induced Shliomis and Polar theory of Eringen. Using theoretical equations and distributions for the velocity, vorticity and angular velocity as the magnetic response, it is shown that magnetic fluid flow is non-Newtonian fluid. We investigate dynamic characteristic of magnetic fluid by comparing longitudinal magnetic field with transverse magnetic field. And, the limits, influence magnetic fluid, of the intensity of the magnetic field with polar, size and magnetic effect parameters are shown.

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Magnetic field imperfections of in-vacuum undulator on PLS-II beam dynamics

  • Chunjarean, Somjai;Hwan, Shin-Seung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.359-359
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    • 2011
  • Many research applications in basic sciences and biology such as protein crystallography require hard x-rays in the range of 3-20 keV with high brightness. A medium energy storage ring as PLS-II with a beam energy of 3 GeV can meet such high photon energies. In-vacuum undulators (IVU) with a period length of 20 mm and a peak field of 0.97 T are used in the PLS-II ring to produce such X-rays in the fundamental or higher harmonics. Due to the many poles and high fields, insertion devices like wigglers and undulators have a significant impact on the stability of the electron beam with potential degradation of beam quality and life time. Therefore, nonlinear fields must be determined by measurement and evaluated as to their impact on beam stability. Specifically, transverse field roll-off can be a serious detriment to injection in top-up mode and must be corrected. We use magnetic field measurement data to evaluated beam stability by tracking particles using an explicit symplectic integrator in both, transverse and longitudinal planes.

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The Analysis of a TFLIM for Electro-magnetic Levitation and Propulsion (자기부상(부(浮上) 및 추진(推進) 겸용 TFLIM의 해석)

  • Jang, Seok-Myeong
    • Proceedings of the KIEE Conference
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    • 1987.11a
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    • pp.37-40
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    • 1987
  • In transverse flux linear induction motors(TFLIM), The loops of the working flux lie in planes transverse to the direction of motion. With a poly-phase primary winding, The TFLIMs has both electro-magnetic propulsion and levitation force. Thus, TFLIM a will be useful in high speed ground transportation systems. In this paper, The characteristics of a single aide TFLIM are analysed by using electromagnetic field theory.

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Comparison of Transverse Flux Rotary Machines with Different Stator Core Topologies

  • Lee, Jiyoung;Chung, Shiuk;Koo, Daehyun;Han, Choongkyu
    • Journal of Magnetics
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    • v.19 no.2
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    • pp.146-150
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    • 2014
  • The objective of this paper is to provide a comparison between two transverse flux rotary machines (TFRM) with different topologies of stator cores. Depending on how to make stator core with laminated steel sheets, the one topology is 'perpendicular stacking core' and the other is 'separated core'. Both of the two cores have been designed considering 3-dimensional (3-D) magnetic flux path with the same output power conditions, but the core losses are quite different and it causes different magnetic and thermal characteristics. For comparison of these two topologies of stator cores, therefore, core losses have been calculated and used as a heat source in no-load conditions, and the thermal stress has been also calculated. 3-D finite element method has been used for the magnetic field, thermal, and stress analysis to consider the 3-D flux path of the TFRM. After comparing the analysis results of the two topologies, experimental results are also presented and discussed.

Unbalanced Magnetic Forces in Rotational Unsymmetrical Transverse Flux Machine

  • Baserrah, Salwa;Rixen, Keno;Orlik, Bernd
    • Journal of Electrical Engineering and Technology
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    • v.7 no.2
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    • pp.184-192
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    • 2012
  • The torque and unbalanced magnetic forces in permanent magnet machines are resultants of the tangential, axial and normal magnetic forces, respectively. Those are in general influenced by pole-teeth-winding configuration. A study of the torque and unbalanced magnetic forces of a small flux concentrating permanent magnet transverse flux machine (FCPM-TFM) in segmented compact structure is presented in this paper. By using FLUX3D software from Cedrat, Maxwell stress tensor has been solved. Finite element (FE-) magneto static study followed by transient analysis has been conducted to investigate the influence of unsymmetrical winding pattern, in respect to the rotor, on the performance of the FCPM-TFM. Calculating the magnetic field components in the air gap has required an introduction of a 2D grid in the middle of the air gap, whereby good estimations of the forces are obtained. In this machine, the axial magnetic forces reveal relatively higher amplitudes compared to the normal forces. Practical results of a prototype motor are demonstrated through the analysis.

Transmit Receive RF Resonator Optimization at 7 T MRI System (7 T 자기공명영상시스템에서의 송수신 RF 공진기 최적화)

  • Alam, Mohammad Wajih;Yoo, Hyoungsuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.10
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    • pp.1727-1730
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    • 2016
  • Magnetic resonance imaging has a potential to produce clear anatomical as well as functional images of human body. However, the ability to diagnose is limited by signal to noise ratio (SNR) and the resolution of current medical systems. To remove the challenges prevalent due to the use of high field scanners, dedicated radio frequency coils are used. Transverse electromagnetic coils have an advantage of providing homogeneous magnetic field throughout the region but with low signal to noise ratio while surface coils have an advantage of providing higher signal to noise ratio but with low homogeneity. This research combines both the advantage into one by utilizing transmit only transverse electromagnetic radio frequency coils (8 channel) along with receive only surface coils (by varying the number) for better imaging of brain. A 7 Tesla 32-channel close fitting helmet shaped phased-array surface coils along with the combination of 8 channel transmit only transverse electromagnetic coils provided good homogeneity as well as significant SNR improvements throughout the human brain.

Decoupling of Thrust Force and Levitation Force of Transverse Flux Linear Induction Motor by the Active Compensation of Magnetic force across the Air-Gap (공극력의 능동적 보상을 통한 횡자속 선형 유도 구동기의 추력과 부상력의 비연성화)

  • 정광석;백윤수
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.11
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    • pp.91-98
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    • 2004
  • TFLIM(Transverse Flux Linear Induction Motor), making its closed magnetic path with the direction of the traveling field orthogonal, had been developed to decrease an edge effect of the general induction motor. To control the levitation force and the thrust force on the secondary part of TFLIM independently, the various methodologies have been presented. When we try to achieve the independent control using only the multi-phase inputs assigned in the stator coils as an approach, in which condition we can minimize the coupling effect between two forces\ulcorner In this paper, we show the qualitative influence of a slip frequency, an ac magnitude, a dc offset superposed in the ac power, and a major parameter of TFLIM on the couple through the computer simulation. And to realize the independent motions between levitation and thrust motion without any auxiliary means fur isolation of the secondary part of TFLIM, the decouple compensator is suggested, including the experimental results.

Dynamics of Transverse Magnetic Domain Walls in Rectangular-shape Thin-film Nanowires Studied by Micromagnetic Simulations

  • Lee, Jun-Young;Choi, Sang-Kook;Kim, Sang-Koog
    • Journal of Magnetics
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    • v.11 no.2
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    • pp.74-76
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    • 2006
  • Dynamic behaviors of transverse domain walls (TDWs) in rectangular shaped thin-film magnetic nanowires with different widths under applied magnetic fields less than the Walker field were studied by micromagnetic simulations. It was found that the velocity of stable TDWs in the viscous region increases from 147 to 419 m/s and their mass decreases from $6.24{\times}10^{-23}\;to\;2.70{\times}10^{-23}kg$ with increasing strength of the applied magnetic field ranging from 5 to 20 Oe for the nanowire with a dimension of 10 nm in thickness and $5{\mu}m$ in length, and 50 nm in width. With increasing the width of nanowires from 50 to 125 nm at a specific field strength of 5 Oe, the TDW's velocity also increases from 147 to 246 m/s and its mass decreases from $6.24{\times}10^{-23}\;to\;5.91{\times}10^{-23}kg$.