• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.33-37
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• 2013

In this study a new design concept of the Fabry-Perot filter, constructed with an anisotropic space layer and a couple of isotropic mirrors, was proposed based on the Maxwell equations and the characteristic matrix method. The single- and double-cavity Fabry-Perot filters were designed, and their optical properties were investigated with a developed software package. In addition, the dependence of the transmittance and phase shift for two orthogonal polarization states on the column angle of the anisotropic space layer and the incidence angle were discussed. We demonstrated that the polarization state of electromagnetic waves and phase shifts can be modulated by exploiting an anisotropic space layer in a polarization F-P filter. Birefringence of the anisotropic space layer provided a sophisticated phase modulation with varied incidence angles over a broad range, resulting in a wide-angle phase shift. This new concept would be useful for designing optical components with isotropic and anisotropic materials.

• 천문학회보
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• 제37권1호
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• pp.96.2-96.2
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• 2012

We statistically examined ULF Pc 3-5 wave power in the regions of undisturbed upstream solar wind, quasi-parallel shock (and foreshock), quasi-perpendicular shock, and the magnetosheath to understand how and to what extent the wave power changes as the solar wind propagates to the magnetosheath. For this study, we used the magnetic field data from the THEMIS spacecraft and Wind (as shifted to the bow shock nose) for May-November in 2008 and 2009. The statistical results show that, in the case of the Pc5 wave power, the sheath power is roughly proportional to the upstream power for both quasi-parallel (and foreshock) and quasi-perpendicular shock regions. Also we identified undisturbed upstream condition from WIND as being well away from foreshock region, and found that the sheath power can be larger for quasi-parallel shock region by a factor of 5-15 than for quasi-perpendicular shock region. In the cases of Pc 3 and Pc4 waves, we found the higher sheath power when associated with the foreshock than with the quasi-perpendicular shock region.

• 전력전자학회논문지
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• 제13권6호
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• pp.476-486
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• 2008

매트릭스 컨버터에서 입력필터의 최적설계는 대단히 중요하다. 그러나 입력필터에 포함된 인덕턴스와 커패시턴스 성분으로 인해 입력 역률이 저하되고 최적 필터 설계에도 불구하고 출력 주파수와 부하에 따라 역률이 바뀌게 되므로 운전조건이 변하면 매트릭스 컨버터의 장점 가운데 하나인 높은 역률을 유지하는 것이 힘들게 된다. 본 논문에서는 매트릭스 컨버터에서 입력필터를 사용할 경우 부하나 출력 주파수가 변동하더라도 입력 역률을 거의 1로 유지할 수 있는 새로운 형태의 공간벡터변조기법을 제안하고 이를 구현할 수 있는 방법을 제시했다.

• 한국전자통신학회논문지
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• 제11권9호
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• pp.855-860
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• 2016

본 연구는 디지털위성중계기용 전원공급기의 설계 및 구현에 대해 기술하였다. 위성버스의 PLDIU(: Payload Distribution and Interface Unit)와 전원공급기의 인터페이스를 제시하였고, 우주환경에 대한 WCA(: Worst Case Analysis)를 통하여 ESD(: Electro Static Discharge) 등의 발생에 대한 회로 오동작 가능성을 최소화 시켰다. 발사환경 시 발생하는 진동 및 우주 방사능에 의한 TID(: Total Ionizing Dose)에 대한 시뮬레이션을 통해 신뢰성 있는 전원공급기를 설계하였으며, 제작 후 우주환경시험을 통하여 기능 및 성능에 문제없음을 확인하였다.

• Journal of Biosystems Engineering
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• 제20권3호
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• pp.205-216
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• 1995

A fast and inexpensive approximate analysis method to predict power output characteristics of the Stilting engines in a preliminary design stage was investigated. In basic equations proposed by Walker, typical temperatures of working fluids in expansion and compression spaces were treated as those of working fluids in heater and cooler respectively. While the temperature of working fluid in the expansion space was actually lower than that of working fluid in the heater, the temperature of working fluid in the compression space was higher than that of working fluids in the cooler. In this paper, the working fluid temperature of expansion space was treated as lower than the heater temperature and that of compression space was treated as higher than the cooler temperature. Also, according to them, the power output characteristics of the Stirling engine were evaluated with respect to the GPU-3 and 4-215 Stilting engines. The following conclusions were drawn from the analysis. 1. Using the available experimental data from the GPU-3 Stirling engine, it was shown that the approximate analysis predicts the brake power with a maximum error of 19 percent at 1, 000rpm and with a minimum error of 3 percent at 2, 000rpm. 2. The approximate analysis data which for the GPU-3 Stirling engine were much closer to the experimental data than those of adiabatic 2nd order and 3rd order analysis within 1, 500rpm to 2, 500rpm. 3. The approximate analysis data which for the GPU-3 and 4-215 Stilting engines were much closer to the experimental data than those of the Beal number analysis.

• 한국실내디자인학회논문집
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• 제16권5호
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• pp.81-88
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• 2007

Energy consumption has been increased world widely, and the energy retain is one of the most important economic alternatives. These tendencies expand the nuclear power plants not only quantitatively but also qualitatively. Despite of the increasing construction of nuclear power plants and related facilities, every system in main control room(MCR) has been designed and administered solely based on the safety-first principles because of the specificity of nuclear industry. However, recent main control rooms started with the concept that the operators' performance could be optimized though the organic interrelation between human, machine, and environments. Now, it has been recognised in the scope of Ergonomics and Space Design which acknowledge our living spaces as Man-Environment Interface and this change connotes the MCR spaces should be special spaces rather than ordinary spaces. This research investigated domestic and foreign nuclear power plants' MCRs to suggest basic alternatives which can be applied to future MCR. With the review of characteristics of MCR, an integration of interior design, lighting and Ergonomics was explored and classified as types. Futhermore, the classification of environmental characteristics within the relationships between human, machine, and environments was developed through the case analysis of nuclear power plants. The results of this study will provide a basis of space design for system environments that the high level of safety and function are extremely important.

• 전력전자학회논문지
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• 제9권4호
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• pp.303-310
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• 2004

본 연구에서는 순시전압 sag 및 고조파 전류 보상을 위한 공간벡터 검출법을 기반으로 한 3상 하이브리드 직렬형 능동전력필터 시스템을 제안하고 있다. 순시전안 sag 및 고조파 전류를 검출하기 위한 공간벡터 검출법은 종전의 이론에 비해 곱셈 연산 과정을 감소할 수 있고 좌표 변환이 필요치 않기 때문에 간략화한 보상 알고리즘 구현이 가능하다. 본 연구의 타당성은 전력전자전용 시뮬레이터 PSIM에 의해 정상상태와 과도상태에서 입증하였다. 그 결과 3상 교류 전원 모두에 순간적인 전압 sag가 발생되거나, 임의의 상에 왜형 및 sag가 있는 경우, 전압 보상 및 고조파 전류 보상이 모두 가능함을 입증하였다.

• 한국전자통신학회논문지
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• 제16권3호
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• pp.437-442
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• 2021

본 연구는 우주 인증용 대전자전중계기용 전원공급기의 설계 및 구현에 대해 기술하였다. 위성버스의 PLDIU(Payload Distribution and Interface Unit)와 전원공급기의 인터페이스를 제시하였고, 우주환경에 대한 WCA(Worst Case Analysis)를 통하여 SEU(Single Event Upset) 등의 발생에 대한 회로 오동작 가능성을 최소화 시켰다. 발사환경 시 발생하는 진동 및 우주 방사능에 의한 TID(Total Ionizing Dose)에 대한 시뮬레이션을 통해 신뢰성 있는 전원공급기를 설계하였으며, 제작 후 우주환경시험을 통하여 해당 구성품에 대한 환경 시험 규격에 만족함을 확인하였다.

• 한국전자통신학회논문지
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• 제14권4호
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• pp.693-700
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• 2019

본 논문은 민간 및 공공 소유의 활용 가능한 유휴공간을 더 발굴하고 사례의 다양한 적용을 통해 효율성이 강화된 설비를 적용하여 발전 단가의 지속적인 하락과 육상기반의 지상 발전부지의 부족 및 인허가 애로사항을 효과적으로 대체하는 사례로 연구하고자 한다. 구축 운영 사례를 바탕으로 분석 요인의 도출과 요인별 가변조건에 따라 경제적 가치와 수익성을 시뮬레이션을 하였고 태양광발전소의 수익모델 후속 발굴 연구에 활용될 수 있도록 한다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.331-332
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• 2014

Underground power plant is required the strict safety management and safety assessment. Because it is the high risk of explosion by characteristic of enclosed space. In case gas leak of enclosed space, the ventilation facilities is very important in order to prevent explosion by the maintain less than the LEL(lower explosive limit). Thus, Through a safety assessment of ventilation volume is to reduce the risk for ventilation facilities in Underground power plant.