• KIEAE Journal
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• 제2권3호
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• pp.33-38
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• 2002

The intermediate range of temperatures($100{\sim}300^{\circ}C$) which can be achieved with CPCs(Compound Parabolic Concentrators) without tracking device provides both economic and thermal advantages for solar collector design. The present paper summarizes critical design considerations for CPC with cylindrical absorber and its optical performance using ray tracing program. Concentration ratios vary as acceptance half angle, ratio of reflector height to aperture width and ratio of reflector area to aperture area. This effects showed that the concentration ratio was increased as acceptance angle but optimum ratio of reflector height to aperture width existed at critical value. As a result of ray tracing, solar ray losses was maximized at acceptance half angle and this problem was solved by increasing absorber tube diameter. The concentrating flux distribution on the absorber surface was uniform but peak flux existed.

• 한국군사과학기술학회지
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• 제5권2호
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• pp.123-131
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• 2002

ASC(Avionics System Computer) was developed to control weapon delivery and navigation sensors, and to perform man-machine interface with pilots for XKO-1 aircraft. The data communications between ASC and UFC(Up Front Controller), DC(Data Concentrator) were implemented by RS422 serial data bus. Also, SCIL(Standard Computer Interface Library) was designed to facilitate control and management of the computer hardware resources and is embedded in the ASC. These structures have a merit of noise immunity and a reduction of wire harness for signal lines, and enable OFP(Operational Flight Program) programmers to use the SCIL easily without knowing hardware details. Manufactured system was on installed on XKO-1, and peformed for BIT(Built In Test) and interface test with UFC and DC. The test results show that it meets the system requirements.

• Bulletin of the Korean Chemical Society
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• 제22권2호
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• pp.171-178
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• 2001

A Purge and Trap Concentrator has been used to analyze various volatile organic compounds in water, operating several parameters affecting the extraction efficiencies of these compounds. The object of the present study was to observe the purge efficiencies of 40 volatile organic compounds (VOCs) in water, according to the change of parameters (purge time, dry purge time, sample temperature), and to determine the optimum condition of analysis of VOCs. The Purge and Trap Concentrator was interfaced with a narrow capillary connected to a gas chromatography mass spectrometer. At this condition, the detection limits of VOCs were in the range of 0.1-0.5 ㎍/L.

• Current Optics and Photonics
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• 제8권4호
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• pp.375-381
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• 2024

In this report, we present the design, fabrication, and experiment of a static solar system for electric vehicle (EV) applications. The static concentration component is composed of compound parabolic concentrators (CPCs) couplings with multi-junction solar cells, where a flat silicon panel is added to the bottom of the CPV structure to maximize power generation. This design allows the system to collect both direct sunlight and diffused sunlight. The CPCs were fabricated with acrylic with a geometric concentration ratio of 4×. We built a prototype with a (3 × 3) cell array of CPCs with a thickness of 25 mm, which is as thin as conventional flat photovoltaic panels, and performed an outdoor experiment that showed that after six hours of operation, the system had an acceptance angle of approximately 43° and an average daily efficiency of 22.85%.

• ETRI Journal
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• 제8권2호
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• pp.37-44
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• 1986

TDX-1의 digital speech data path를 형성하는 digital line concentrator(DLC)와 스위치 네트워크의 구성 및 동작에 관하여 서술하였으며, TDX-1 스위치 네트워크의 종합적인 통화량에 관하여 고찰하였다.

• 한국태양광발전학회지
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• 제4권1호
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• pp.16-22
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• 2018

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2001년도 추계 학술발표회 논문집
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• pp.299-302
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• 2001

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2010년도 춘계학술대회 논문집
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• pp.606-607
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• 2010

• 한국정보처리학회논문지
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• 제3권7호
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• pp.1868-1879
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• 1996

현재 이동통신시스템의 내부 프로세서간 통신망은 메쉬 토폴로지 형태의 단일 버 스를 이용하기 때문에 앞으로 B-ISDN과 연계될 대용량의 트래픽 처리에 한계가 있다. 또한, 이동통신시스템에서는 일반 ATM망에서의 고정 길이가 아니니 가변 길이 패킷을 사용하고 있으므로 ATM스위치를 그대로 이용할 수는 없다. 일부의 구현에서 가변길이 를 지원하는 스위치를 제시하고 있으나, 내부 동기화를 위한 전처리, 비트 지연 등의 문제가 있다. 본 논문에서는 추가적인 처리없이 가변길이의 패킷을 처리할 수 있는 경합집속기를 설계하였다. 또한 제안된 경합집속기는 입력 인터페이스에서 패킷 시작 신호를 위한 지연이 없다. 따라서, 효율적으로 패킷을 처리해 줄 수 있으며, 기존의 경합집속기에 N 비트 시간의 지연이 걸리던 것을 $\ulcornerlog2N\lrcorne＋1$ 비트 시간 정도로 감소 시켰다. 이에 따라 가변 길이 넉아웃 스위치를 적용한 부분 메쉬 토폴로지의 버스 구 조의 이동통신시스템은 B-INDN망과 연계된 대용량의 트래픽을 처리할 수 있을 것으로 기대된다.

• Advances in Energy Research
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• 제4권4호
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• pp.299-323
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• 2016

Cylindrical parabolic solar concentrators of small concentration ratio are attractive options for working temperatures around $120^{\circ}C$. The heat gained can be utilized in many applications such as air conditioning, space heating, heating water and many others. These collectors can be easily manufactured and do not need to track the sun continuously. Using a heat pipe as a solar absorber makes the system more compact and easy to install. This study is devoted to modeling a system of cylindrical parabolic solar concentrators of small concentration ratio (around 5) fitted with a heat pipe absorber with a porous wick. The heat pipe is surrounded by evacuated glass tube to reduce thermal losses from the heat pipe. The liquid and vapor flow equations, energy equation, the internal and external boundary conditions were taken into consideration. The system of equations was solved and the numerical results were validated against available experimental and numerical results. The validated heat pipe model was inserted in an evacuated transparent glass tube as the absorber of the cylindrical parabolic collector. A calculation procedure was developed for the system, a computer program was developed and tested and numerical simulations were realized for the whole system. An experimental solar collector of small concentration, fitted with evacuated tube heat pipe absorber was constructed and instrumented. Experiments were realized with the concentrator axis along the E-W direction. Results of the instantaneous efficiency and heat gain were compared with numerical simulations realized under the same conditions and reasonably good agreement was found.