• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.391-396
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• 1998

Foreign bodies in genitourinary tract are common and almost of them are within the bladder. These foreign bodies were inserted or applied for autoerotic, psychiatric, therapeutic, or no definite reasons by the patient. Foreign bodies(a thermometer and a piece of cloth) in the bladder were inserted as a mean of masturbation in two cases, and a cooper wire in the posterior urethra was introduced by iatrogenic causes in one case. In one case, four magnets were inserted into the bladder for the purpose of forceful penile erection. Clinical history, symptom, radiologic study, and endoscopic examination were required to diagnose foreign body. They were easily removed by endoscopic manipulation or open surgical procedure.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1332-1336
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• 1990

This paper deals with some analytical and experimental aspects to control a multi-magnet suspended vehicle. Because the response of a multi-magnet vehicle shows mutually coupled interaction, an analytical description of the vehicle dynamics is necessary. For numerical computations, a linearized modelling of vehicle dynamics is dicussed and computer simulation is carried out. And for the experiment, a test vehicle suspended by four magnets has been made and investigated by local control of each magnet. Two algorithms by PID and state feedback control law are used and compared with each other. Some kinds of disturbance characteristics and coupling effects of the width change of the test vehicle are experimented.

• Journal of Magnetics
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• v.20 no.3
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• pp.201-206
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• 2015

Using the Vienna ab initio simulation package (VASP) incorporating both semiempirical and nonlocal van der Waals interaction, the structural, adsorption, and magnetic properties of Ni/BN/Co systems were investigated. We proposed that the relative spin direction of Ni and Co magnets can be easily tuned, because the total energy difference between ferromagnetic (FM) and antiferromagnetic (AFM) states is small. Despite this feature, very interestingly, both Ni and Co layers manifest half-metallic state, whereas the spacer BN layer becomes weak metal for one monolayer (ML) thickness and an insulating barrier for two ML thicknesses. The half-metallic behavior of the magnetic layers seems very robust, because it is independent of the magnetic coupling between Ni and Co. This finding indicates that the Ni/BN/Co system can be used as a potential candidate for tunneling magnetoresistance system.

• Journal of Magnetics
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• v.19 no.3
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• pp.282-290
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• 2014

This paper discusses the development of a 3.5 kW switched reluctance motor (SRM)-based electric air-conditioning (AC) compressor, focusing primarily on the design aspects of the SRM and the integrated controller. In addition to the increased price of rare-earth magnets, SRM's operation capability at high speed and high temperature makes the SRM a viable alternative to the permanent magnet motor for electrically driven automotive air conditioning compressors. A compact and energy efficient scroll compressor is designed and constructed. Two feasible SRM topologies are considered, in terms of efficiency, torque ripple, and acoustic noise. Compact drive electronics are designed and employed to drive the SRM-based compressor. The static and dynamic performance is validated by simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.5
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• pp.249-256
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• 1999

This paper describes static characteristics analysis of linear pulse motor(LPM) with two permanent magnets. Linear pulse motors are finding a wide range of application for the Factory-Automation or the Office-Automation. Typically, LPM provides for a reliable and precise control of position, velocity, or acceleration without using a closed-loop system. Some of the advantages of LPMs are ease of control, step multiplication, static and dynamic positioning, and locking force. The flux density and thrust of LPM is computed by the FEM and magnetic equivalent circuits which considered the magnetic nonlinear phenomena. The result of characteristics analysis are shown as the flux, the air gap reluctance and the thrust. The velocity and position characteristics as a function of unit step input is measured. To estimate the unit step response charecteristic of LPM, the simulation results by Matlab and the experimental results is compared.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.767-768
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• 2006

Cogging torque is produced in a permanent magnet machine by the magnetic attraction between the rotor-mounted permanent magnets and the stator. It is an undesired effect that contributes to the machines' output ripple, vibration, and noise. This paper presents the stator design for reducing cogging torque in the BLDC motor by using the DOE(Design of Experiments). The cogging torque is computed by using a two-dimensional finite element analysis.

• Journal of Magnetics
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• v.18 no.4
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• pp.432-442
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• 2013

For magnetically suspended flywheel (MSFW) with gimballing capability, demerits of Lorentz force-type magnetic bearings and common reluctance force-type magnetic bearings are analyzed, a novel reluctance forcetype magnetic bearing (RFMB) including radial and axial magnetic bearing units with 4 separate biased permanent magnets and two conical stators is presented. By equivalent magnetic circuits' method, its magnetic properties are analyzed. To reduce the eddy loss, it was designed as radial poles with shoes and its rotor made of Iron-based amorphousness. Although the uniformity of magnetic flux density in the conical air gap determines mainly the additional tilting torque, the maximum additional tilting torques is 0.05Nm and the rotor tilting has no influence on its forces when the rotor tilts or the maximum changes does not exceed 14% when the rotor drifts and tilts simultaneously. The MSFW with this RFMB can meet the maneuvering requirement of spacecraft theoretically.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.207-210
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• 1997

The Linear D.C Motor with moving magnet type structured two permanent magnets, three iron bars and winding copper around one of bars. This paper describes the design theory and trust characteristic analysis of Linear D.C Motor. The design theory is very important to Motor design. Here, The design method be obtained by the design theory equation based the flux distribution and design constant. The propriety for this is established by the experiment results.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.232-234
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• 1998

Race-track type superconducting coils are used for wiggler magnets of accelerators and field coils of superconducting generators(S.C.G) and so on. The shape is different from ordinary solenoidal type magnet, so the manufacturing situation and conditions become different and moreover according to these results the output characteristics of magnet also becomes different. In this paper we are dealing with race-track type coil design that is inserted into 30(kVA) S.C.G which will be manufactured before we make l(MVA) S.C.G plant. The design procedure is based on two dimensional electromagnetic analysis including laplace equations in cylindrical coordinate.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.25-27
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• 2005

This paper deals with the comparison and analysis of brushless DC (BLDC) motor with radial and polar anisotropic plastic magnet. The open-circuit field distributions and back-emf for BLDC motor with polar plastic magnet are established analytically and the results are validated extensively by comparison with finite element (FE) analyses. On the basis of two dimensional (2-D) analytical solutions, this paper predicts open-circuit field characteristics according to design parameters and makes a comparison between BLDC motor with polar plastic magnet and it with radial plastic magnet in terms of required magnet volume and harmonic of air-gap flux density waveform.