• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.683-687
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• 2006

This research investigated the effect of aeration pretreatment for anaerobic seed sludge on hydrogen production. Aeration time for anaerobic sludge was maintained at 0, 1, 3, 6, 12, and 24 hours in batch tests. Two continuous anaerobic reactors (aerated and non-aerated) were also operated. All experiments were conducted at $35^{\circ}C$ using mineral salts-glucose (20 g/l) medium. Methane production decreased with the increase in aeration time. Aeration for 6 hours was determined as an optimum from the amount of hydrogen produced. Hydrogen was steadily produced in the continuous reactor seeded with aerated sludge while no methane production was observed. However, small amount of hydrogen was produced in the non-aerated reactor for short period of time from the start even though short HRT (2 days) and low pH (5.5) were maintained.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1215-1216
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• 1995

Planar Solid Oxide fuel cell may have some advantages, particularly in their potential for allowing a higher power density, and simpler, less costly methods of fabrication. This study has examined generation characteristics of unit cell for planar Solid Oxide fuel cell.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.372-375
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• 2006

This paper proposes a parallel operation system of the Z-source active power filter using one fuel cells(FC) system. The proposed system is composed of two Z-source inverters operating in parallel only one PEM(Polymer Electrolyte Membrane)FC system. Also, as the control algorithm of the active power filter, a single phase P-Q theory and PI control are adopted. The effectiveness of the proposed the system is verified by the PSIM simulation in the steady state and the transient state.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1968-1970
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• 1997

유도전동기의 속도 제어 장치로 인버터의 사용이 두드러지고 있으며, 소용량 가변속 드라이브에 있어서 그 제어성의 양호한 범용 인버터 구동이 현 인버터 시장의 주류를 이루고 있다. 그러나 범용 인버터는 종래의 TR구동 인버터에 비해 스윗칭 횟수가 많고 데드타임의 영향이 크게 나타난다. 본 논문에서는 유도전동기를 운전하는 범용인버터에 대하여 데드타임으로 인한 문제 해결 및 전류 왜곡 개선 방법을 제안하였고, 이를 실험적인 결과로 입증하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.88-89
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• 2015

본 연구에서는 선박에서 발생하는 휘발성유기화합물을 처리하기 위하여 친환경적인 대기오염방지설비를 개발하기 위하여 유용미생물 담체를 충전한 바이오필터를 사용하여 VOCs가스를 처리하는 실험실 규모의 실험을 수행하였다. VOCs가스의 온도, pH, 습도, 가스농도와 VOCs가스 제거효율과의 상관관계를 도출하고 이를 바탕으로 바이오필터의 전반적인 VOCs가스 제거효율 및 수명 그리고 안정성 등을 평가하였다. 최적 조건에서의 VOCs 제거 효율은 유입되는 오염가스 농도가 2000ppmv까지 모든 범위에서 90%이상의 제거효율을 나타내는 것으로 보아 이 범위에서 안정적인 운전이 가능한 것으로 평가된다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.129-133
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• 2010

A hybrid system which is combined several complementary new and renewable power sources, such as photovoltaic, fuel-cell, and wind generator, etc., has been presented in various approaches. For instance, a photovoltaic cannot always generate stable output power with ever-changing weather condition, so it might be co-generated with a wind generator, diesel generator, and some other sources. In this paper, a residential PV-FC hybrid system is suggested as a distribution power source, and its operation is optimized by HOMER$^{(R)}$. As a result, it is the most economic that 5[kW] PV, 1[kW] FC, 4 batteries, 2[kW] electrolyzer, 0.5[kg] $H_2$ tank, 3[kW] converter are applied to the hybrid system.

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.3-10
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• 2002

In this work, numerical parametric studies on spray combustion have been conducted. In simulation of turbulence, RNG ${\kappa}-{\varepsilon}model$ is adopted. Initial spray distribution is specified by Rosin-Rammler distribution function. Eddy break-up model is adopted as a combustion model. The parameters considered are inlet air temperature, swirl number, and SMD. With higher inlet air temperature, the axial velocities are increased and penetration of primary jet is stronger than that of lower inlet air temperature and temperature at the exit of combustor is more uniform. Combustion efficiency is improved with high inlet air temperature. The effect of swirl number on flow field is not significant. It affect only recirculation zone. So temperature at upstream of combustor is influenced. Combustion efficiency deteriorate as SMD of fuel spray increase.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.615-617
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• 2008

본 논문에서는 태양에너지 실증연구단지에 설치된 서로 다른 2기 3kW급 태양광발전 시스템에 대한 5년간의 데이터 분석을 통하여 시스템 구성요소인 태양전지와 인버터의 효율 특성 및 시스템의 운전특성의 경년변화에 대하여 비교분석하였다. A 시스템의 경우 PV 어레이 변환효율은 2004년 이후 약 0.2% 정도로 지속적으로 떨어지는 추세를 나타내고 있으며, B 시스템의 경우 인버터의 효율은 약 0.5% 정도로 지속적으로 떨어지는 추세를 나타내고 있다. 2기의 PV 시스템의 발전효율, 이용율 및 성능비는 모두 2004년 이후 지속적인 효율저하를 나타내고 있음을 확인 하였다.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.177-178
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• 2006

The enhancement of system security is one of the most important objectives of UPFC operation. To describe the system security, the index related to line flows and bus voltages are used. For the enhancement of security, the operation point of UPFC is set to minimize the index. This paper proposes the minimization algorithm using the Marquardt method. Moreover, the coefficients minimizing iteration number will be derived. For verification of the proposed operation scheme, numerical simulations have been performed on power system in Kwanju area, Korea with a UPFC.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2546-2548
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• 1999

This paper describes characteristics of independent load sharing of parallel UPS systems and proposes a method of control which does not require control interconnections at each UPS system and compensates for line impedance. Simulation results of a two-module UPS system with different power latins and line impedance have demonstrated the feasibility of the proposed control scheme in load sharing.