• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.29-36
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• 1998

In this paper, two-stage braking method of 3-phase induction motrois proposed. This brake involves tow stages. The first stage is capacitor self-excitation braking, and the second stage is three-phase magnetic braking. In several applicatons, a low cost and effective brake is required for three-phase induction motor. A mechanical friction brake, typical braking method for induction motor requires external energy sources which is not safe, expensive and requires maintenance. Static and dynamic analyses of the proposed brake scheme are along with analytical result, simulated waveforms and experimental waveforms are compared. The experimental results shows good agreement with the simulated results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.90-97
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• 2015

This paper discusses to the capability improvement of the 1/4 HP compressor. And, for efficiency improvement of the single phase induction motor, this paper has proposed a casting method to improving the fill factor of the rotor of the single phase induction motor. First, by using FEM, it was analyzed the magnetic flux distribution and the fill factor to the SPIM rotor by the conventional method and the proposed method. And, based on the FEM analysis results, SPIMs are manufactured by the each casting process. Through experiments using dynamometer, they were compared and measured to their efficiencies. In addition, through experiments using Calorimeter, we have analyzed the refrigerating capacity of the compressor of which they were applied. Based on the results of the previous two experiments, they are to verify the validity of the proposed method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.6
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• pp.650-655
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• 1996

In order to investigate the effects of added magnetized water on the callus induction and plant regeneration in rice, 700G(G=Gauss) magnetized water were used. The callus in-duction and plant regeneration of rice in magnetized water treatment are different from the callus induction and plant regeneration in ionic water treatment. The rates of callus induction in magnetized water media were 27.3% in solid media and 15.4% in liquid which were compared to that of callus induction in the ionic water media 21 and 13.3%. Also plant regeneration frequency in the magnetic water media is 5.4% better than that of the ionic water media. And dissolved oxgen amount of magnetic culture media is from 0.1 ppm to 0.9 ppm more than that of ionic culture media. The pH value was increased with rising of water temperature, and the magnetic water was effected at increasing of pH value.

• Computers and Concrete
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• v.21 no.3
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• pp.239-248
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• 2018

This study developed and investigated a precast slab track system partially reinforced with glass fiber reinforced polymer (GFRP) rebars in the transverse direction, which mitigated the loss of track circuit current by reducing magnetic coupling between the rails and steel reinforcements. An electric analysis was conducted and the results of the analysis verified that the GFRP rebars mitigate the reduced current strength produced by electro-magnetic induction. In the study, a three-dimensional finite element method and flexural experiments were used to study the mechanical behavior of the proposed slab track.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.5
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• pp.228-233
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• 2002

A computational method for analysis of the 3 dimensional electro-magnetic induction problems has been developed. The developed method is capable of modeling the induced current and analyzing its characteristics using only scalar Potential at each node. A benchmark model of asymmetrical conductor with a hole is analyzed to verify the application of the developed method. The calculated value of magnetic flux density are compared with the measured value, and the results indicate that the developed method is valid. Also, Comparing with 3-D finite element method (FEM) results, we conformed effectiveness of the developed method for the accuracy and computation times.

• Journal of Acupuncture Research
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• v.30 no.5
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• pp.95-105
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• 2013

Objectives : The purpose of this study is to examine the preparing methods of the traditional acupuncture needle and to interpret the electromagnetic meaning intervened in them. Methods : The overall manufacturing processes of the acupuncture needles in ancient books were surveyed. And the facts that special functional activities were carried out in common in the preparing processes were detected. The reproduction tests for the detected former functional activities were followed. Results : According to the ancient medical books, the traditional acupuncture needles were treated with the magnet through the preparing processes. The reproduction tests provided the fact that the ferromagnetic iron needles treated with the magnet were enhanced their magnetisms. And major techniques of the ancient supplementation and draining can be interpreted as magnetic or induced electromagnetic actions. Conclusions : Considering the electromagnetic characteristics of human body, the magnet treated ferromagnetic iron needles of ancient era and magnetic or induced electromagnetic interpretable manipulation techniques are the historical evidences of magnetic activities of acupuncture. So modern acupuncture therapy should be understood, studied, and reinterpreted as an electromagnetic viewpoint.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1269-1283
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• 2011

Here we consider magneto-convection in a mushy layer which is formed during solidification of binary alloys. The mushy layer is treated as an active porous media with variable permeability. The equations governing the layer are conservation of mass, conservation of heat, conservation of solute, magnetic induction equation, momentum equation governed by the Darcy's law and Maxwell's equations for the magnetic field. To study the second order effects on the flow without solving the second order system, we need to obtain the adjoint system for the flow. This motivates the authors we derive the adjoint system analytically for the mushy layer case. Numerical results of the adjoint system are presented for passive and active mushy layers at the onset of the motion using a set of parameters experimentalists use.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.78-85
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• 2011

In order to design the control system of the magnetic bearing for the high speed 3 phase induction motor, the mathematical modeling was conducted and LQ regulator system was designed. When the plant is controllable and detectable, the nominal stability of LQ regulator could be guaranteed. However, LQ regulator doesn't ensure the robustness of stability and performance for the real system because LQ control is the mathematical optimal theory. In this paper to ensure the robustness of stability and performance for the real system, the control systems are designed by the simulation to the variation system parameters and this method was confirmed as an effective means.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.868-870
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• 2001

Salient pole rotor type single phase SRM(switched reluctance motor) can be use axial direction magnetic flux and radial direction magnetic flux at the same time. Then, it has higher energy density per unit volume and can be lessened the shaft length of motor or exciting magnetic force. Additionally, it's durability is good because it is simple structure and driving device. Prototype of Salient pole rotor type single phase SRM was fabricated by using parameters of three phase SRM and 3D FEM analysis. Also, driving device was fabricated for prototype. Speed and torque characteristic was confirmed through the experiments, and flux linkage, which is important parameter of SRM for generating torque, was measured. The induction emf was calculated by using ideal inductance graph and current graph. Calculated emf and measured emf was compared for confirming loss of prototype in this paper.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.693-695
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• 2001

A computational method for the 3 dimensional electro-magnetic induction problems has been developed. The proposed method is capable of modeling the eddy current and analyzing its characteristics using only scalar potential. A benchmark model of asymmetrical conductor with a hole is analyzed to verify the application of the developed method. The calculated value of magnetic flux density are compared with the measured value, and the results indicate that the developed method is valid.