• Structural Engineering and Mechanics
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• 제22권1호
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• pp.85-105
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• 2006

Control of structural response due to seismic excitation in a manner of coupling adjacent buildings has been actively developed, and most attention focused on those buildings of similar height. However, with the rapid development of some modern cities, multi-story buildings constructed with an auxiliary low-rise podium structure to provide extra functions to the complex become a growing construction scheme. Being inspired by the positively examined coupling control approach for buildings with similar height, this paper aims to provide a comprehensive analytical study on control effectiveness of using friction dampers to link the two buildings with significant height difference to supplement the recent experimental investigation carried out by the writers. The analytical model of a coupled building system is first developed with passive friction dampers being modeled as Coulomb friction. To highlight potential advantage of coupling the main building and podium structure with control devices that provide a lower degree of coupling, the inherent demerit of rigid-coupled configuration is then evaluated. Extensive parametric studies are finally performed. The concerned parameters influencing the design of optimal friction force and control efficiency include variety of earthquake excitation and differences in floor mass, story number as well as number of dampers installed between the two buildings. In general, the feasibility of interaction control approach applied to the complex structure for vibration reduction due to seismic excitation is supported by positive results.

• 전기전자학회논문지
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• 제24권1호
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• pp.140-146
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• 2020

We investigated light extraction film based on polymer dispersed liquid crystal (PDLC) for application in organic light emitting diodes (OLEDs). At least 30 seconds of direct UV irradiation process for curing PDLC film on a bottom-emitting OLEDs was successfully achieved without damage on the intrinsic properties of the OLED. We demonstrated that high haze and transmittance can be tuned simultaneously by controlling the UV curing time. By adding PDLC as an external layer without any additional treatment, the light scattering and extraction is increased. Consequently, a PDLC scattering film with 89.8% and 59.9 of total transmittance and haze respectively, achieved about 16% of light intensity enhancement from integrating sphere measurement.

• Journal of Information Display
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• 제5권1호
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• pp.7-15
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• 2004

A highly simplified backlight unit mainly composed of diffractive grating in sub-micron order imprinted light-guide plate (LGP) is proposed for edge-lit backlight unit. Optical characteristics of the imprinted LGP are examined by RCWA and the performance is verified through Monte Carlo simulation. Results show that the diffraction efficiency, luminous flux and its uniformity over the area are significantly affected by the angle of incident ray. Consequently couples of design considerations are additionally proposed to enhance luminous flux. In terms of peak luminance and out-coupling luminous flux, the experimental results are agreed well with the performance simulation. Finally, compared with optical characteristics of conventional backlight unit, we could conclude that the proposed simplified backlight unit made of diffractive grating imprinted light-guide plate is a good substitute for the conventional backlight unit.

• 한국광학회지
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• 제20권1호
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• pp.1-5
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• 2009

최근 광 격자구조나(photonic crystal) 표면 플라즈몬파(surface plasmon) 혹은 실리콘을 이용한 나노(nano) 스케일의 광 회로 시스템에 대한 연구가 활발한데, 이는 이미 한계에 다다른 전자회로속도의 한계를 극복하고 지금보다도 훨씬 작은 회로를 구성할 수 있는 이점이 있기 때문이다. 현재까지 보고된 바 있는 광 결합 시스템들은 그 크기가 나노 스케일의 광 회로 시스템에 비해 커서 광 결합 시스템으로서의 의미가 퇴색되고 있는데 본 논문에서는 매우 짧은 초점 거리를 가지며 매우 얇은 구조를 가지는 프레넬 렌즈를 이용한 광 결합 시스템을 제안하여 광 결합 시스템을 나노 스케일 광 회로 시스템과 비교할 수 있을 정도로 소형화 하는 방법을 모색하였다. 본 논문에서는 금 슬릿을 채용한 프레넬 렌즈를 제안하여 설계하고 그 구조를 이용해 2차원 전산모사를 수행하였다. 그 결과, 일반 프레넬 렌즈의 광 결합 효율이 약 43%인데 반해, 금 슬릿을 채용한 프레넬 렌즈의 광 결합 효율은 가장 효율적인 구조로 설계하였을 경우에 최대 약 65%의 광 결합 효율을 보인다. 일반 프레넬 렌즈에 비해 50% 이상의 광 결합 효율의 향상을 달성하였다.

• Journal of Power Electronics
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• 제17권6호
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• pp.1694-1706
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• 2017

Models and experiments for magnetic resonance coupling wireless power transmission (MRC-WPT) topologies such as the chain topology and branch topology are studied in this paper. Coupling mode theory based energy resonance models are built for the two topologies. Complete energy resonance models including input items, loss coefficients, and coupling coefficients are built for the two topologies. The storage and the oscillation model of the resonant energy are built in the time domain. The effect of the excitation item, loss item, and coupling coefficients on MRC systems are provided in detail. By solving the energy oscillation time domain model, distance enhancing models are established for the chain topology, and energy relocating models are established for the branch topology. Under the assumption that there are no couplings between every other coil or between loads, the maximum transmission capacity conditions are found for the chain topology, and energy distribution models are established for the branch topology. A MRC-WPT experiment was carried out for the verification of the above model. The maximum transmission distance enhancement condition for the chain topology, and the energy allocation model for the branch topology were verified by experiments.

• Journal of Information Display
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• 제10권2호
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• pp.92-95
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• 2009

Highly efficient blue and white phosphorescent organic light-emitting diodes (PHOLEDs) with an exciton-confining structure were investigated in this study. Effective charge confinement was achieved by stacking two emitting layers with different charge-transporting properties, and blue PHOLEDs with a maximum luminance efficiency of 47.9 lm/W were developed by using iridium(III) bis(4,6-(difluorophenyl) pyridinato-N,C2')picolinate (FIrpic) as an electrophosphorescent dopant. Moreover, when the optimized green and red emitting layers were sandwiched between the two stacked blue emitting layers, white PHOLEDs (WOLEDs) with peak external and luminance efficiencies of 19.0% coupling technique.and 54.0 lm/W, respectively, were obtained without the use of any out-coupling technique.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.111-114
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• 2001

In this paper, the electromagnetic coupling problems are tackled on slots with nonzero thickness. The analysis is carried out by combination of the thin-wire concept and the Method of Moment(MoM) for the sake of improving computation efficiency. Under the conditions to be presented, slots can be replaced with wires that have effective radii. Also, the infinite summation-type Green's functions are calculated for the parallel-pale structure. A slot in an infinite ground is analyzed and its results are compared with the measurement in a literature. Furthermore, it is examined how the slots couple in parallel plates.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.86-92
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• 2000

Recently, the Korea National Railways (KNR) is undertaking a program of electrification of the existing railway routes. In order to implement the ongoing plan, KNR authorized a preliminary engineering study of its electrical systems. This effort included a comprehensive analysis of new grounding networks. The new grounding system runs in parallel with the rails and is connected to all metal structures such as rails, overhead protection wires and substation grounding grids etc., creating an equipotential ground network. This paper presents a study on coupling levels that can disturb signaling and telecommunications in adoption of the new grounding network The simulation for the study is carried out using Matlab software, Several different scenarios are analyzed, including the load condition and a few fault conditions with different fault locations. The induced potentials on the communication cables are computed. The effect of the buried ground wires is also analyzed by comparing the results with and without the presence of the ground wires, The results presented in the paper can be used as a reference for estimating coupling levels in similar rail systems.

• 전자공학회논문지D
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• 제35D권9호
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• pp.93-99
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• 1998

수직 방향성결합기 구조에서 결합파장 및 결합분포를 달리하는 결합기 4개를 포함하는 헙대역 파장역다중기를 제안하고 동작특성을 모의실험 하였다. 너비가 다른 네 개의 ridge 광도파로를 동일한 strip상에 집적하여 수직결합시킴으로써 각각의 ridge 광도파로가 개별 파장여과기로 동작한다. 각 채널에서 발생하는 부엽(side-lobe)을 억제하기 위해 두 광도파로 간의 결합계수를 광파 진행방항으로 변화시켰다. 모의실험 결과 1.55 ㎛ 중심파장 대역에서 채널간격은 7 nm 이고 각 채널은 1.7 nm의 3-dB 통과대역폭, 20dB의 부엽억제비 및 약 90%의 광전력 전달효율을 보이면서 각 채널이 균일한 광여과 응답특성을 나타냄을 알 수 있었다.

• 한국자동차공학회논문집
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• 제24권2호
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• pp.161-168
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• 2016

CNG engine has been used as a transportation because of higher thermal efficiency and lower CO2 and particulate matter. However its out put power is decreased due to cylinder-to-cylinder variation during the supply of air-fuel mixture to the each cylinder. It also causes noise and vibration. So in this study, 1D engine simulation model was validated by comparison with experiment data and 3D CFD simulation was conducted to steady-state flow analysis about each manifold geometry. Then, the effects of various intake manifold geometries on variation were evaluated by using 1D-3D coupling analysis at engine speed of 2100 rpm range in 12 L CNG engine. As a result, variation was improved about 4 % though 3D CFD analysis and there was a variation within 3 % using 1D-3D coupling analysis.