• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.4
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• pp.335-341
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• 2016

In this paper, we propose the method of controling the turns of a receiving coil for the matching directly to the receiver input impedance(typically $50{\Omega}$) with a maximum wireless power transfer(WPT) efficiency. Based on the presented the expression of the optimum load depending on a system figure of merit, number of the turns of a receiving coil, and proximity effect between conducting lines, the theoretical efficiencies have been compared with the measured ones with a good agreement. The results of this work may be used to realize a allowable maximum efficiency with a simple and low-profile 2-coil WPT system not requiring a separate feeding loop.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.905-909
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• 1995

We constructed the large 3-axis square Helmholtz coil system for the power frequency magnetic field immunity test. We measured the coil factors and magnetic field homogeneities of the fabricated 3-axis square Helmholtz coil. The experimental results for the field homogeneities are in agreement with the theoretical data. From these results, we determined the effective areas for the immunity test. We also confirmed that the low current using the multi-turns coil can be applicable to the immunity test for the high field in short duration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.84-90
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• 2018

In constructing the multi-body dynamics model to analyze the behavior of the railway vehicle, it is very important to understand the properties of the suspension elements that constitute the suspension system. Among them, coil springs, which are mainly used in primary and secondary suspension systems, clearly show the axial stiffness in the drawings, but the lateral properties of the coil springs are not specified clearly, making it difficult to construct a dynamic analysis model. Therefore, in this paper, the model for analyzing the lateral stiffness of the coil spring is examined. A finite element method was applied to analyze the lateral stiffness of the coil spring and numerical analysis was performed by applying the coil spring lateral stiffness analysis model proposed by Krettek and Sobczak. And the test to analyze the lateral stiffness of coil spring was conducted. As a result of comparing with the test results, it was found that the results obtained by applying the lateral stiffness analysis model of Krettek and Sobczak and correcting the correction coefficient are similar to those of the test results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1120-1124
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• 2013

Our objective of this study was to reduce radio frequency coil (RF) control time at 3 T MRI systems. A compressed method is proposed with a convex optimization and pseudo-inverse method in multi-channel RF coils. After applying the proposed methods, fields are homogenized with less field data. Even with 80% compression, the fields are well homogenized and localized, indicating that mapping requires only 20% of the original data. Detailed values are compared between each compressed result in and outside the region of interest at 3 T.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.132-134
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• 2001

In this paper, by designning the width of the stator coil, double sided excitation LDM with multi-separated winding which is possible to obtain the constant thrust force is proposed. Using Maxwell 2D, Empulse, we were proved the characteristic analysis of LDM accoding to ratio magnet width venus coil width of LDM. Though designning for double sided excitation LDM with multi-separated winding, we could be achieved the constant thrust and rapidly time responses within the operating region.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.290-293
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• 2000

In this paper, by designing the width of the stator coil, double sided excitation LDM with multi-separated winding which is possible to obtain the constant thrust force is proposed. Using Permeance method, equvalent magnetic circuit method, Maxwell 2D, which is the magnetic field analysis package, we were analyzed and proved the validity of design process, also the characteristics of LDM according to magnet vs. coil width ratio of LDM was almost in accord with the experiment results.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.207-215
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• 2017

The superior performance of the spherical actuator is establishing a new trend in the industry. Spherical actuators can perform multiple degrees-of-freedom (DOF) motions by using only one actuator. Therefore, a multi-DOF device using the spherical actuator can reduce weight and simplify the structure. This paper proposes a new spherical actuator that uses the operational principle of a rotational voice coil motor. The effectiveness of the actuator is verified through 3-D finite element method.

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.46-46
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• 2006

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.56-56
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• 2003

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.254-255
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• 2012