• 조명전기설비학회논문지
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• 제23권8호
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• pp.8-13
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• 2009

LED 광원 기술의 발전과 더불어 응용분야도 다양하게 넓어지고 있다. 이중 본 논문에서는 액정 후면 배광 장치와 같이 고성능의 광원이 요구되는 응용제품에 적합한 광원을 제작하였다. 논문에서 제안한 광원은 금속산화물 절연층을 이용하여 LED chip에서 발생한 열을 효율적으로 외부로 전달하는 구조를 적용하였으며 패키지 구조가 아닌 chip과의 접촉면에 반사컵 구조를 적용하여 배광 분포 제어와 광자 재흡수 특성을 개선하였다.

• 한국태양에너지학회 논문집
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• 제31권3호
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• pp.73-79
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• 2011

ORC(organic Rankine cycle) has potential of reducing consumption of fossil fuels and has many favorable characteristics to exploit low-temperature heat sources. This work analyzes performance of ORC with superheating using low-temperature energy sources in the form of sensible energy. Maximum mass flow rate of a working fluid relative to that of a source fluid is considerd to extract maximum power from the sources. Working fluids of R134a, $iC_4H_{10}$ and $C_6C_6$, and source temperatures of $120^{\circ}C$, $200^{\circ}C$ and $300^{\circ}C$ are considered in this work. Results show that for a fixed source temperature thermal efficiency increases with evaporating temperaure, however net work per unit mass of source fluid has a maximum with respect to the evaporating temperature in the range of low source temperature. Results also show that the maximum power extraction is possible with R134a for the source temperature of $120^{\circ}C$, with $iC_4H_{10}$ for $200^{\circ}C$, and with $C_6C_6$ for $300^{\circ}C$.

• 전기전자학회논문지
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• 제26권2호
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• pp.205-210
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• 2022

본 연구에서는 유기 발광 다이오드(OLED)의 광추출 향상을 위한 롤투롤 마이크로컨택(mCP)방식으로 인쇄된 마이크로렌즈 어레이(MLA)를 제시하였다. 상업적으로 사용되는 마이크로렌즈 어레이를 템플레이트로 사용하여서 polydimethylpolysiloxane(PDMS)를 롤스탬프로 제작하였다. 낮은 끓는 점을 가지는 불소화 잉크로부터 PDMS 롤스탬프에 고분자 박막을 형성하고 이를 OLED의 하부면에 고압·고온 처리 없이 인쇄하였다. 최적화된 농도를 찾아서 템플레이트로 사용된 MLA와 거의 동일한 모양의 패턴을 성공적으로 인쇄하였다. 마이크로컨택 방식으로 인쇄된 MLA의 구조와 소재의 낮은 흡수도로 인해서 OLED의 외부양자효율이 18% 향상되었다.

• 한국정보시스템학회지:정보시스템연구
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• 제32권4호
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• pp.137-147
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• 2023

Purpose The domestic aquaculture industry in South Korea utilizes both formulated feeds and live feeds for the cultivation of fish. While nutrient-rich live feeds, particularly using fry, have been preferred since the past, formulated feeds are gaining attention due to issues related to overfishing and environmental concerns. Formulated feeds are advantageous for storage and supply but require a sustained feeding regimen due to the comparatively slower growth rate compared to live feeds. As the aging population in rural areas leads to a shortage of labor, automated feeding systems are increasingly being adopted in aquaculture facilities. To enhance the efficiency of such systems, it is crucial to quantitatively analyze the behavioral changes in fish based on the presence or absence of feed. Design/methodology/approach In the study, RGB cameras and infrared cameras were used to analyze fish activity according to feeding, and an outline extraction algorithm was applied to analyze the differences resulting from this. Findings Unlike RGB cameras, infrared cameras are more suitable for analyzing underwater fish activity as they convert objects' thermal energy into images. It was observed that Canny, Sobel, and Prewitt filters showed the most distinct identification of fish activity.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권4호
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• pp.454-461
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• 2015

Light enhancement of GaN based light emitting diodes (LEDs) have been investigated by texturing the top p-GaN surface. Nano-textured LEDs have been fabricated using self-assembled Ni nano mask during dry etching process. Experimental results were further compared with simulation data. Three types of LEDs were fabricated: Conventional (planar LED), Surface nano-porous (porous LED) and Surface nano-cluster (cluster LED). Compared to planar LED there were about 100% and 54% enhancement of light output power for porous and cluster LED respectively at an injection current of 20 mA. Moreover, simulation result showed consistency with experimental result. The increased probability of light scattering at the nano-textured GaN-air interface is the major reason for increasing the light extraction efficiency.

• 공업화학
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• 제29권4호
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• pp.474-478
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• 2018

Thermal decomposition of waste Achyranthes Root (WAR) emitted from its decoction process was investigated using a TG analyzer and a fixed-bed reactor. The WAR had the larger C and fixed carbon content than fresh AR (FAR) due to the extraction of hemicelluloses from FAR during decoction process. Thermogravimetric (TG) analysis results also revealed the elimination of hemicellulose by its decoction. Relatively high contents of the cellulose and lignin made high contents of their typical pyrolyzates, such as acids, ketones, furans, and phenols, in the pyrolysis of WAR using the fixed-bed reactor. The increase of pyrolysis temperature from 400 to $500^{\circ}C$ increased yields of oil and gas due to the more effective cracking efficiency of WAR at a higher temperature. The chemical composition of product oil was also changed by applying the higher pyrolysis temperature, which increased the selectivity to furans and phenols.

• 방사선산업학회지
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• 제6권2호
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• pp.125-128
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• 2012

Kenaf (Hibiscuc cannabinus L.) is a renewable resource for industry and kenaf lignin is syringyl-guaiacyl lignin. The electron beam irradiated on kenaf core various doses range from 200 to 1,000 kGy to improve delignification. The yield of lignin, which is 2.53 g from 10 g of electron beam irradiated kenaf core. A comparison extracted lignin between from native kenaf core and electron beam irradiated kenaf core was then studied through chemical structure and bonding property by a Fourier transform infrared spectroscopy (FT-IR). Thermal stability of the extracted-purified lignin was performed via differential scanning calorimetry (DSC). These results were explained that electron beam irradiation increased performance of extracting efficiency.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1687-1697
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• 2024

This study presents the Supporting platform for reactor fine flow characteristics calculation and analysis (Cilian platform), a user-friendly tool that supports the analysis and optimization of pressurized water reactor (PWR) cores with mixing vanes using computational fluid dynamics (CFD) computing. The Cilian platform allows for easy creation and optimization of PWR's main CFD calculation schemes and autonomously manages CFD calculation and analysis of PWR cores, reducing the need for human and computational resources. The platform's key features enable efficient simulation, rapid solution design, automatic calculation of core scheme options, and streamlined data extraction and processing techniques. The Cilian platform's capability to call external CFD software reduces the development time and cost while improving the accuracy and reliability of the results. In conclusion, the Cilian platform exemplifies an innovative solution for efficient computational fluid dynamics analysis of pressurized water reactor (PWR) cores. It holds great promise for driving advancements in nuclear power technology, enhancing the safety, efficiency, and cost-effectiveness of nuclear reactors. The platform adopts a modular design methodology, enabling the swift and accurate computation and analysis of diverse flow regions within core components. This design approach facilitates the seamless integration of multiple computational modules across various reactor types, providing a high degree of flexibility and reusability.

• 공업화학
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• 제3권1호
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• pp.130-137
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• 1992

과산화벤조일을 개시제로 하여 클로로프렌 고무에 아크릴로니트릴(AN)과 스티렌(ST)을 그라프트 공중합하였다. 합성된 그라프트 공중합체는 초산에틸/n-헥산, 아세톤/메탄올 및 디메틸포름아미드/메탄을 혼합용매를 사용하여 추출 분리하였다. 얻어진 그라프트 공중합체인 아크릴로니트릴-클로로프펜-스티렌(ACS)수지는 IR분광법으로 구조를 확인하였다. 그라프트 공중합시의 스티렌 대 아크릴로니트릴 몰비,반응온도와 시간, 개시제농도, CR농도 및 용매의 영향을 고찰한 결과 그라프팅 효율은 [ST]/[AN] 몰비와 반응시간, 개시제 농도와 CR농도에 따라 증가하였다. 그라프트 공중합에서 클로도프렌의 농도는 9.6wt%, 단량체의 상대적 몰비, [ST]/[AN]=1.5, 반응시간은 40시간, 반응온도는 $70^{\circ}C$가 최적 반응조건이었다. 아울러 최적반응조건으로부터 합성되어진 그라프트 공중합체의 열적성질 난연성 내후성 및 morphology도 측정조사하였다. 그 결과 난연성과 내후성 및 열적 안정성이 기존의 ABS나 AES보다 개선되었다.

• 에너지공학
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• 제11권2호
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• pp.81-89
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• 2002

석탄가스화 복합발전(IGCC)은 석탄을 가스화하고 가스화된 연료를 사용하여 전기를 생산하는 기술로 기존의 석탄 전환 기술에 비해 전환율이 높고 환경 영향이 적은 것으로 알려져 있다 특히 우리나라와 같이 전력 생산 분야에서 석탄 화력의 비중이 높은(2001년 6월 기준, 29.6%, 한전통계자료)나라에서 급격히 강화되는 석탄 화력 발전 방식에 대한 오염물 배출량 제한에 대처하기 위해 기존 석탄 화력의 대안으로 석탄가스화 복합발전이 부각되고 있다. 본 연구에서는 국내 도입이 임박한 IGCC상용설비를 대상으로 한 시스템 설계 연구를 수행하였다. 분류층 가스화 공정을 채용한 2가지 종류의 IGCC시스템으로, 고효율 IGCC와 저비용 IGCC에 대해 시스템 연계 최적화를 고려하여 시스템을 설정하였다. 각 시스템에 대해 AspenPlus등을 사용한 시스템 시뮬레이션 모델을 개발하고 성능 계산을 수행하였으며 특히 저비용 IGCC 시스템에 대해서는 시스템 옵션 스터디와 공기 추출율에 따른 민감도 분석을 수행하였다. 열성능 계산 결과 고효율 IGCC 시스템의 효율이 42.6%(HHV, Net)으로, 저비용 IGCC 시스템에 75% 공기 추출율을 적용한 경우 40%(HHV, Net)으로 나타났다.