• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.73-78
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• 2008

A polarimetric fiber-optic CT has been developed by using a sensing coil made of a length of sun fiber. A Faraday rotator mirror is attached to the end of the sensor coil to double the sensitivity and to suppress the residual linear birefringence effect. From the current measurements, the linear error no more than ${\pm}2[%]$ was obtained. The output of spun fiber sensor coil was compared with those of the twisted- and the flint glass fiber's, and it fumed out to almost 50 times, 2 times more sensitive, respectively.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.4
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• pp.394-398
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• 2013

This paper presents output characteristics of a linear switched reluctance motor (LSRM) with excitation windings wound by using high-temperature superconducting (HTS) tapes. In a double-sided LSRM, Bi-2223 or YBCO tape conductors are used for the excitation windings. The characteristics of the LSRM are obtained by a finite element method analysis. We can obtain large thrust compared with a conventional LSRM by using YBCO tape conductors. Also, the effect of a configuration of the YBCO coil on the thrust is calculated. We discuss a suitable coil configuration for the average thrust upgrading.

• Journal of electromagnetic engineering and science
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• v.13 no.1
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• pp.51-53
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• 2013

A MIMO antenna using the resonance of ground planes is proposed for 4G mobile application. A resonant mode is generated when the double ground planes (upper and lower) in the mobile terminal are excited as the radiator. By combining the resonant modes contributed from both the antenna element and the ground planes, the proposed MIMO antenna realizes a wideband property over LTE band 13. In addition, an inductive coil is employed to reduce the antenna volume. These approaches not only simplify antenna design but also effectively improve bandwidth and efficiency. The proposed MIMO antenna has an excellent ECC value of below 0.1 because of the nearly orthogonal radiation patterns of the two radiators. Moreover, an additional antenna is adopted to cover WiMAX, WLAN, and Bluetooth services simultaneously in frequency range from 2 GHz to 2.7 GHz.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1712-1720
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• 2016

AC and DC insulation breakdown voltage was studied for magnet wire coated with double layers of high flexural PAI layer and high anti-corona PAI/nanosilica (15 wt%) layer. The specimens were prepared at various drying temperatures (T/D): $22^{\circ}C$, $240^{\circ}C$, and $260^{\circ}C$, respectively. The increase effects of nanosilica on AC and DC insulation breakdown voltage were not so significant compared to that of magnet wire coil coated with original PAI. And the AC and DC insulation breakdown voltage was improved by decreasing diameter of winding coil. As T/D temperature increased, AC and DC insulation breakdown voltage decreased.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.96-103
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• 2013

In this paper, resonant wireless power transfer systems are designed with double loop resonant coils for the resonant frequency of 150kHz. The transfer efficiency characteristics is analyzed according to the coil size, and the distance and misalignment between the coils. Then the change in efficiency is investigated when a human model is located between the resonant coils using the homogeneous human phantom of IEC-62311 standard. Also, in order to assess the safety of the wireless power transfer system, the induced current density inside the human model is calculated when it is exposed to the magnetic field of a plane wave and resonant coil. Then, the results are compared with the exposure limits in the EMF (electromagnetic field) safety guidelines.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.291-291
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• 1999

Long 19-filamentary Bi-2223 tapes were prepared using the so called "powder-in-tube" method. In the preparation, two types of precursor powders and two different reduction rates during rolling were used. Also two rolling method, which resulted in different filament geometry, were used. The characteristics of the tapes will be presented. Also A coil was prepared using two 56 m-long 19-filament tape. It was consisted of two double pancake coils. Each pancake, which is separated by FRP spacer, was composed of 98 turns. The experimental results will be presented and compared to the simulation result.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.48-49
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• 2001

Cryogenic technology is one of the key technologies for fusion reactor equipped with superconducting coil for plasma confinement. The KSTAR(Korea Superconducting Tokamak Advanced Research)Project is in progress since 1996. Major parameters of the KSTAR tokamak are : major radius 1.8m, minor radius 0.5m, toroidal field 3.5 Tesla and plasma current 2MA with a strongly shaped plasma cross-section and double -null diverter. Considering practical engineering constraints, the KSTAR device is designed for a pulse length of 300 sec in up-graded operation mode but in the initial configuration would provide a pulse length of 20 sec provided by the poloidal coil system in base-line operation mode. The cryogenic system is composed as follows : cold box, helium compressor system, distribution box, helium gas buffer tank, helium gas purifying system, gas recovery system, liquid helium storage dewar, current lead box, current bus line and liquid nitrogen storage tank.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.420-423
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• 2002

In this paper the characteristics of surface flashover for high temperature superconducting transformer(HTS) was discussed. The transformer, will be developed in the shell type with double pancake coil, isn't developed yet in the world. We conducted experiment of surface flashover that could occur in the windings of the transformer. First, we distinguished the surface flashover with electrode alignment into two type, such as parallel and vertical, and then compared with each characteristics of surface flashover. And the surface flashover with metallic particle was tested, it was also affected by the particle position. .

• Progress in Superconductivity
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• v.3 no.2
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• pp.159-162
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• 2002

We have detected cracks inside multi-layer metal sheets with nondestructive evaluation system consisting of SQUID gradiometer. Double D-shape coil was carefully designed with computer simulation for spatial distribution of magnetic field. It was aligned and placed in between SQUID and metal sheets in order to reduce the field effect to SQUID and to maximize eddy current in the sheets. The metal plate in bottom of the metal stack contained artificial cracks which were scanned by an X-Y scanning system. The information of crack position and size could be estimated by analysis of SQUID signal. Details of the results will be discussed .

• Progress in Superconductivity and Cryogenics
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• v.21 no.4
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• pp.53-58
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• 2019

The critical current is one of the key parameters of high temperature superconducting (HTS) racetrack coils. Therefore, it is significant to calculate critical currents of HTS coils. This paper introduces a fast iterative algorithm for calculating the critical current of second generation (2G) HTS coils. This model does not need to solve long charging transients which greatly reduced the amount of calculation. To validate this model, the V-I curve of four 2G HTS double racetrack coils are measured. The effect of the silicon steel sheet on the critical current of the racetrack coil is also studied based on this algorithm.