• 한국토양비료학회지
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• 제49권5호
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• pp.495-502
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• 2016

Italian Ryegrass (IRG), which is known as high yielding and the highest quality winter annual forage crop, is grown in mid-south area in Korea. The objective of this study was to evaluate the use of unmanned aerial vehicle (UAV) for the monitoring IRG growth. Unmanned aerial vehicle imagery obtained from middle March to late May in Nonsan, Chungcheongnam-do. Unmanned aerial vehicle imagery corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). We analyzed the relationships between $NDVI_{UAV}$ of IRG and biophysical measurements such as plant height, fresh weight, and dry weight over an entire IRG growth period. The similar trend between $NDVI_{UAV}$ and growth parameters was shown. Correlation analysis between $NDVI_{UAV}$ and IRG growth parameters revealed that $NDVI_{UAV}$ was highly correlated with fresh weight (r=0.988), plant height (r=0.925), and dry weight (r=0.853). According to the relationship among growth parameters and $NDVI_{UAV}$, the temporal variation of $NDVI_{UAV}$ was significant to interpret IRG growth. Four different regression models, such as (1) Linear regression function, (2) Linear regression through the origin, (3) Power function, and (4) Logistic function were developed to evaluate the relationship between temporal $NDVI_{UAV}$ and measured IRG growth parameters. The power function provided higher accurate results to predict growth parameters than linear or logistic functions using coefficient of determination. The spatial distribution map of IRG growth was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when $NDVI_{UAV}$ was applied to power function. From these results, $NDVI_{UAV}$ can be used as a new tool for monitoring IRG growth.

• 동력기계공학회지
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• 제5권2호
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• pp.50-56
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• 2001

In this study, the effect of specimen thickness and stress ratio on fatigue crack growth in S45C steel was investigated. Acoustic emission was monitored during the fatigue crack growth test. Both crack closure and AE technique were used in assessing fatigue crack growth behavior. Constant amplitude loading tests were performed on CT type specimen with three different thicknesses and stress ratios. Crack closure was investigated to explain the influence of specimen thickness and stress ratio on the fatigue crack growth in the second growth region. The crack closure effect was decreased with specimen thickness and stress ratio.

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.384-389
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• 2009

KEPRI (Korea Electric Power Research Institute) has studied planar type solid oxide fuel cell (SOFC) stacks using anode-supported cells and kW class co-generation systems for residential power generation. In this work, a 1 kW SOFC system consisted of a hot box part, a cold BOP (balance of plant) part, and a hot water reservoir. The hot box part contained a SOFC stack made up of 48 cells, a fuel reformer, a catalytic combustor, and heat exchangers. Thermal management and insulation system were especially designed for self-sustainable operation in that system. A cold BOP part was composed of blowers, pumps, a water trap, and system control units. When the 1 kW SOFC stack was tested using hydrogen at $750^{\circ}C$, the stack power was about $1.2\;kW_e$ at 30 A and $1.6\;kW_e$ at 50 A. Turning off an electric furnace, the SOFC system was operated using hydrogen and city gas without any external heat source. Under self-sustainable operation conditions, the stack power was about $1.3\;kW_e$ with hydrogen and $1.2\;kW_e$ with city gas respectively. The system also recuperated heat of about $1.1\;kW_{th}$ by making hot water.

• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.419-424
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• 2010

The 125kW external reforming (ER) type molten carbonate fuel cell (MCFC) system for developing a commercial prototype has been operated at Boryeong thermal power plant site since the end of 2009. The system consists of 125kW stack with $10,000 cm^2$ effective area, mechanical balance of plant (MBOP) with anode recycle system, and electrical balance of plant (EBOP). The 125kW MCFC stack installed in December, 2009 has been operated from January, 2010 after 20 days pre-treatment. The stack open circuit voltage (OCV) was 214V at initial load operation, which approaches the thermodynamically theoretical voltage. The stack voltage remained stable range from 160V to 180V at the maximum generating power of 120 kW DC. The stack has been operated for 3,270 hours and operated at rated power for 1,200 hours.

• KEPCO Journal on Electric Power and Energy
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• 제6권4호
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• pp.359-379
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• 2020

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.914-917
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• 2002

Fabrication of micro carbon structures and patterns using laser-assisted chemical vapor deposition is studied. Argon ion laser and ethylene were used to grow micro carbon rod through pyrolytic decomposition of the reaction gas. The influence of reaction gas pressure and incident laser power on the diameter and growth rate of the micro carbon rod was experimentally investigated. The diameter of micro carbon rods increases linearly with respect to the laser power but is almost independent of the reaction gas pressure. Growth rate of the rod changes little with gas pressure when the laser power remains below 1W. When the carbon rod was grown at near threshold laser power, a very smooth surface is obtained on the rod. By continuously moving the focusing lens in the direction of growth, a micro carbon rod with a diameter of 28 ${\mu}{\textrm}{m}$ and aspect ratio of 100 was fabricated.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2009년도 Korea Superconductivity Society Meeting 2009
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• pp.90-90
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• 2009

• 벤처혁신연구
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• 제4권2호
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• pp.57-75
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• 2021

한수원은 전력 에너지를 생산하는 우리나라의 대표적인 공기업의 하나이며, 국가 자본에 의해서 생산·유통 또는 서비스를 공급할 목적으로 운영된다. 한수원의 경우는 국민 복지나 국가 발전을 위해 원전 중심의 첨단산업을 영위하며 공기업으로 운영된다. 원자력과 수력발전은 공공재의 성격이 뚜렷하기 때문이다. 사례에서 살펴본 한수원의 동반성장 활동은 공익을 우선하는 공공선에 근거를 두고 있다. 한수원은 종합에너지기업, 첨단 플랜트기업, 동반성장 선도기업이라는 특성을 반영하여 협력사와 동반성장을 위해 추진과제와 성과지표를 연계하는 전략을 제시하고 다양한 방안을 실천해 나가고 있다. 이를 정리라면 ① 원전 생태계유지, ② 협력기업 경영여건 개선, ③ 원전산업계 미래역량 강화, ④ 지역발전 선순환 지원 등이 핵심과제라 할 수 있다. 이것은 원자력발전이라는 특수성을 최대한 반영하여 만든 것이며 에너지 공기업으로서 특성을 최대한 감안하면서도 시대적 과제를 해결하기 위해 상생과 협력을 통한 동반성장 정신을 잘 반영하여 설계되어 있다. 세부 추진과제로 원전 생태계 유지를 위해 신시장·신산업 육성, Supply Chain 유지, 코로나19 긴급지원 등도 제시하고 있다. 한수원의 이런 활동은 본업에 충실하면서도 코로나19 사태이후 사회적 공공선의 철학을 반영한 것이다. 협력기업 경영여건 개선을 위해서는 생산성 향상, 인적자원 강화, 맞춤형 자금지원을 세부과제로 실천하고 있다. 본업에 충실하면서도 협력기업과의 동반성장을 추구하는 한수원의 노력은 기업의 사회적 책임(CSR), ISO 26000 등에서 강조하는 협력기업과 상생을 통한 동반성장의 모범사례라 할 수 있다.

• 한국전기전자재료학회논문지
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• 제33권2호
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• pp.114-117
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• 2020

In this study, we performed the deposition of Al thin film using a DC magnetron sputtering method. To evaluate electrical and structural properties, the growth conditions were changed in terms of two functions, namely, sputtering power ranging from 41.6 to 216 W and film growth rate ranging from 5.35 to 26.39 nm/min. The growth rate and the microstructure were characterized by a scanning electron microscopy and X-ray diffraction analysis. The plane of crystalline growth showed that the preferential (111) direction and defects due to the grain boundary increased with DC power. The resistivity of the Al film over 50 nm showed a constant value by horizontal grain growth. Our results can be applicable for the preparation of nano-templates for anodic aluminum oxide.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.293-297
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• 2000

Multiseeding with (100)/(100) grain junctions of top-seeded melt growth (TSMG) processed YBCO superconductors was studied. The effect of the number of seeds and the distance between two seeds on the levitation forces and the trapped magnetic fields of the TSMG-processed YBCO samples was investigated. Multiple seeding shortened the processing time for the fabrication of TSMC-processed YBCO superconductors. The large magnetic field was trapped at the grain junction when two seeds was placed without spacing, while the amount of the magnetic field decreased when the seed distance increased. This is attributed to the increased amount of the residual melt phases around the grain junctions.