• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.133.2-133.2
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• 2014

A gap surface plasmon resonator have received considerable attention because it can dramatically enhance the absorption of the electromagnetic field. However, whereas most of studies were just focused on the absorption within a narrow range of wavelength, few studies have been performed for the broadband absorption in the visible range. Therefore, in this study, we discuss methods that can induce broadband light absorption using gap plasmon resonance in visible regime. The gap plasmon resonator will offer great potential for appplications to solar cells and bioimaging.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.706-712
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• 1998

Previous counter-current flow limitation (CCFL) and critical heat flux (CHF) studies included investigations on the inlet entrance, inclined channel and gap effects for the most part. In this study, the local CHF correlation was presented to be used in the numerical analysis for the 3 dimensional hemispherical geometry. Also, first-principle analyses were performed to determine the maximum heat removal capability from the debris through the gap that may be formed during a core melt accident. The maximum heat removal capability by gap cooling can be applied in quantitatively assessing the severe accident management measures.

• Journal of Digital Convergence
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• v.5 no.1
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• pp.117-130
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• 2007

This paper examines whether there exists discrimination of the information usage pattern between tenants of permanent and temporary public rental housing in Korea. Moreover, we focus to examine on that matters between two groups, $7{\sim}12$ pyeongs and $11{\sim}24$ pyeongs that indicate permanent and temporary public rental housing respectively. The results derived in this paper can be summarized as follows: there exists statistical significance in using computer, internet, communication and broadcasting, on the other hand, insignificance in using satellite communication and telephone between them. The implication of this results shows that as widen income gap, also widen gaps in using computer and internet between them. Thus government public rental housing policy should focus to make narrow income gap to diminish information gap between those groups.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.386-392
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• 1998

Previous counter-current flow limitation (CCFL) and critical heat flux (CHF) studies included investigations on the inlet entrance, inclined channel and gap effects for the most part. In this study, the local CHF correlation was presented to be used in the numerical analysis for the 3 dimensional hemispherical geometry. Also, first-principle analyses were performed to determine the Maximum heat removal capability from the debris through the gap that may be formed during a core melt accident. The maximum heat removal capability by gap cooling can be applied in quantitatively assessing the severe accident management measures.

• Progress in Superconductivity and Cryogenics
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• v.10 no.4
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• pp.1-5
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• 2008

Flow and heat transfer characteristics of liquid nitrogen in narrow annular channels are very important for many practical applications. In the present study, the experimental investigation of flow boiling of liquid nitrogen in narrow annular channels with gap size of 0.2 and 0.5 mm is carried out. The pressure drop and heat transfer coefficients are experimentally measured. The comparison of the theoretical models for the pressure drop and the correlations of the flow boiling to the experimental results are carried out.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.7
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• pp.359-364
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• 2000

This paper is introducing a newly developed spark-gap switch with dual trigger system, into which the current from the voltage source is injected along with the test sequence during the synthetic testing of high voltage circuit-breaker. The currently-used spark gap switch is narrow in operating range due to the use of the method of triggering energy being injected by single way. As a result, the frequent happening of misoperation has greatly reduced the test quality and test efficiency and has required the cost of maintenance excessively. In this study, accordingly, in order to basically remove these problems, another triggering system is installed to the opposite direction on the existing triggering system; attaching the same time and the same rising time of pulse wave as on the existing system, so that at a comparatively trigger gap distance from the main electrode(the gap can be operated at 60% of self-break voltage, while at 80% in the current system), the main electrode has been enabled to be closed by the development of spark gap switch with dual trigger system.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.310-312
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• 2006

Maglev using EMS becomes unstable by unexpected big air-gap disturbance. The main causes of the unexpected air-gap disturbance are step-wise rail joint and large distance between rail splices. For the stable operation of the Maglev, the conventional system uses the threshold method, which selects one gap sensor among two gap sensors installed on the magnet to read the gap between magnet and guide rail. But the threshold method with a wide bandwidth makes the discontinuous air-gap signal at the rail joints because of the offset in air gap sensors and/or the step-wise rail joins. Further more, in the case of the one with a narrow bend-width, it makes Maglev system unstable because of frequent alternation. In this paper, a new method using fuzzy rule to reduce air-gap disturbances proposed to improve the stability of Maglev system. It treats the air-gap signal from dual gap sensors effectively to make continuous signal without air gap disturbance. Simulation and experiment results proved that the proposed scheme was effective to reduce air-gap disturbance from dual gap sensors in rail joints.

• Journal of Ship and Ocean Technology
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• v.8 no.1
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• pp.42-50
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• 2004

In these ten years, the cavitation and erosion phenomena in the rudder have been increased for high-speed container ships. The cavitation in the rudder blades which is injurious to rudder efficiency is mainly caused by the main flow with a large angle of attack induced by propellers, and the erosion which occurs as a result of repeated blows by shock wave that cavitation collapse may produce was observed in the gap legion of the rudder. However, gap cavitation is not prone to occur in model experiments because of low Reynolds number. So, the viscous effect should be considered for solving the flow of the narrow gap. In order to predict the cavitation phenomena and to improve the performance of the rudder, the analysis of the viscous flow in the rudder gap is positively necessary. In this study, numerical calculation for the solution of the RANS equation is applied to the two-dimensional flow around the rudder gap including horn part and pintle part. The velocity and pressure field are numerically acquired according to Reynolds number and the case that the round bar is installed in the gap is analyzed. For reduced the acceleration that pressure drop can be highly restrained numerically and in model experiment, the cavitation bubbles can be reduced.

• Journal of Welding and Joining
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• v.29 no.6
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• pp.77-81
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• 2011

In most industry, manual GTAW welding is preferred for formation of stable back bead in root weld of butt joint. However, manual GTAW welding has low productivity as compared with GMAW, also it has unstable bead quality which depend on skilled workers. So it is necessary to develop process of root pass welding by using automation GMAW that have stable back bead formation and high productivity. In this paper, the design of U-groove with 3mm root face was applied to extend the tolerance of misalignment in condition of standard root gap 1.5mm. Consequently, for the formation of stable back bead in root pass of butt welding, in case of the narrow root gap(0.5mm) the large arc force was applied by increasing the current and voltage. In case of the large root gap(2.5mm), the small arc force was applied by decreasing the current and voltage. Considering the various root gap, the required deposited metal was controlled by welding speed only.

• Journal of electromagnetic engineering and science
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• v.5 no.3
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• pp.146-151
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• 2005

Electromagnetic penetration into an annular aperture in a thick conducting plane is investigated with the integral transform and eigen-function expansion method. The solution is analytic and is represented in rapidly-convergent series which is amenable to numerical analysis. Numerical computations shows that apertures with narrow annular gap have sharp transmit power peaks in frequency response.