• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.85.1-85.1
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• 2011

Recently, Faraday rotation measure (RM) at high Galactic latitude has been investigated, partly to explore the Galactic magnetic fields and partly to study the extragalactic magnetic fields. The Galactic contribution to RM comes from the global component as well as the turbulent component. So far the turbulent field was used to be analytically modeled with a Kolmogorov-type power spectrum. Here, we present the initial results of the work where the turbulent field is modeled using data of MHD turbulence simulations. Our work is intended to be applied to simulations of RM surveys with LOFAR, ASKAP, MeerKAT, and SKA.

• Journal of electromagnetic engineering and science
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• v.14 no.3
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• pp.317-319
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• 2014

In this letter, a small-loop antenna for a mobile UHF RFID device is proposed. To achieve size reduction, a ferrite sheet optimized for a 900 MHz band is applied. The overall dimensions of the antenna are $46mm{\times}35mm{\times}0.24mm$, and it has a bandwidth of 45 MHz with a return loss of less than -6 dB. The proposed antenna satisfies near and far field UHF EPC global frequency band communications (902-928 MHz).

• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.1-6
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• 2000

Wave energy absorption by a flap equipped with a harbor in a water of finite depth is studied. The wave potential is calculated by a hybrid integral equation consisting of Green integral equations associated with Rankine and Kelvin Green functions. The absorbed wave energy is calculated by both the near-field and far-field methods. The present methods can be used for the design of a flap-harbor wave energy absorber since the numerical results by the two methods are in good agreement.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.191-192
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• 2018

해안을 따라 인구밀도가 증가하고 임해지역공단 등 산업시설이 밀집하여 처리되지 않은 하 폐수가 증가하고 있다. 특히, 최근엔 필리핀 보라카이와 같이 관광 위락시설에 의한 하수가 대량으로 발생하고 있다. 또한, 세계적으로 거의 모든 국가의 주요 해안도시는 이러한 도시하수를 바다로 방류하고 있다. 현재로선 이러한 하 폐수의 처리는 바다의 자정능력(self-purification capacity) 한계를 고려한 하수의 해양으로의 방류가 최선의 방법으로 판단된다. 현재 국내에서는 지역에 따른 배출허용기준에 따라 하수의 처리수 방류가 규제되고 있지만, 확산영역에 대한 법적 기준치는 제시되지 않고 있으며, 인근에 위치한 권리자들과의 이해관계 해결에만 몰두하고 있는 실정이다. 또한 확산영향예측이 원역 해석모형(Far Field analysis model)에 의해 수행되기 때문에 근역(Near Field)에서의 영향을 간과하고 있다고 판단된다. 따라서 금회 연구에서는 기존 연구결과를 기준하여 특정해역에 대한 원역과 근역 해석에 따른 확산영향 예측을 수행하고 그 결과를 비교하여 앞으로의 해석방법을 제시하고자 한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.306-309
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• 2000

The conductive polymers, polyaniline (PANI) emeraldine base and 3, 4-polyethylene dioxythiophene (PEDOT) were synthesized and coated on the PET film primer-dealt with acryl type to find out the electromagnetic shielding effectiveness. When conductive polymer such as PANI and PEDOT is used, if the thickness of coating increases then the electromagnetic shielding effectiveness increases, too, but the visible light transmittance decreases. For PANI, when its conductivity increased, its electromagnetic shielding effectiveness increased, too. For PANI, if the surface resistance is about 140 $\Omega$/$\square$, the shielding effectiveness is about 11 dB in the far field, and about 13 dB in the near field at 1 GHz. For PEDOT, when the surface resistance is about 200 $\Omega$/$\square$, the shielding effectiveness is about 3 dB.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.1
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• pp.24-32
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• 1995

Tsunami generated by the 1992 Nicaragua's west coast earthquake caused 95 persons death, 155 persons injury and 3000 persons homelessness. The previous study done by Imamura et al. (1993) were on the 1992 Nicaragua tsumami generation and propagation which were simulated by using spherical far-field model and Cartesian near-field model, and the computed results with assumption of vertical wall at coast were adjusted by runup ratio to compare with observations. This study using moving boundary model hindcasts El Transito's runup height which was observed as about 6.4-9.9m.

• Economic and Environmental Geology
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• v.18 no.2
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• pp.159-166
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• 1985

The computation of gravity anomalies by multi pole expansion is derived and compared with exact calculation for right rectangular prisms and right circular cylinders. For sources near field points, the multipole expansion results in a better approximation in volume integrals than in surface integrals. Nonetheless two approximate methods are coincident in the far-field of the general geophyical prospecting.

• Transactions on Electrical and Electronic Materials
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• v.17 no.4
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• pp.222-226
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• 2016

This paper investigated the trench process, unified field limit ring, and other products for the development of a 500 V-level unified trench gate power MOSFET. The optimal base chemistry for the device was found to be SF₆. In SEM analysis, the step process of the trench gate and field limit ring showed outstanding process results. After finalizing device design, its electrical characteristics were compared and contrasted with those of a planar device. It was shown that, although both devices maintained a breakdown voltage of 500 V, the Vth and on-state voltage drop characteristics were better than those of the planar type.

• Journal of Mechanical Science and Technology
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• v.19 no.12
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• pp.2263-2269
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• 2005

The ship wave phenomena in the restricted waterway were investigated by a numerical analysis. The Euler and continuity equations were employed for the present study. The boundary fitted and moving grid system was adopted to enhance the computational efficiency. The convective terms in the governing equations and the kinematic free surface boundary condition were solved by the Constrained Interpolated Profile (CIP) algorithm in order to solve accurately wave heights in far field as well as near field. The advantage of the CIP method was verified by the comparison of the computed results by the CIP and the Maker and Cell (MAC) method. The free surface flow simulation around Wigley hull was performed and compared with the experiment for the sake of the validation of the numerical method. The present numerical scheme was applied to the free surface simulation for various canal sections in order to understand the effect of the sectional shape of waterways on the ship waves. The wave heights on the side wall and the shape of the wave patterns with their characteristics of flow are discussed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.82-89
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• 2003

Near-field ground motions exhibit special characteristics that are different from ordinary far-field ground motions. In this study the shaking table tests were conducted to evaluate the effect of earthquake ground motions with different characteristics on the response of the structure. The ground motions used in this study were the scenario earthquake, design earthquake, and Chi-Chi earthquake measured in TCU052 station. These earthquakes have different frequency contents. The test results show that the frequency content of ground motion is very important to the response of structures. The floor responses of structure were greatly affected by the higher modal frequencies, as well as the fundamental frequency. The responses of third floor were significantly reduced due to the interaction between the structure and the base isolated mass installed at the third floor.