• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제24회 춘계학술대회
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• pp.86-93
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• 1996

The lubrication characteristics of high-speed ball bearings has been investigated empirically using 45mm bore split inner ring ball bearings employed in small industrial gas turbine engines with oil-jet lubrication method. For the close structural simulation, experiments carried out with bearing mounting supports of real engines, such as bearing housings and oil nozzle assemblies with squeeze film dampers. Thus the results of tests can be directly applied to the design and the development of gas turbine engines. Testing was done by varying operating speeds, axial load on bearings, and lubricant flowrates. During testing, the temperature of bearing at outer-ring face, the power consumption of the driving motor, and the rotating resistance of the bearing were measured. From this study, the representative factors for lubrication characteristics at high speed was found, and the most important one was not operating speed but axial load up to 1.95 million dmN speed and 303 kgf axial load. Furthermore, the detailed variation of the rotational resistance of the bearing could be visualized by measuring the change of the radial load under the bearing supports. The rotational resistance consists of the frictional resistance and the bearing-cavity oil resistance.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권1호
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• pp.21-32
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• 2013

Marine transportation industry is undergoing a number of problems. Some of these problems are associated with conventional marine fuel-oils. Many researchers have showed that fuel-oil is considered as the main component that causes both environmental and economic problems, especially with the continuous rising of fuel cost. This paper investigates the capability of using natural gas and hydrogen as alternative fuel instead of diesel oil for marine gas turbine, the effect of the alternative fuel on gas turbine thermodynamic performance and the employed mathematical model. The results showed that since the natural gas is categorized as hydrocarbon fuel, the thermodynamic performance of the gas turbine cycle using the natural gas was found to be close to the diesel case performance. The gas turbine thermal efficiency was found to be 1% less in the case of hydrogen compared to the original case of diesel.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.380-386
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• 2020

This paper represents an analysis of the economic impact of firing natural gas/diesel and natural gas/by-product oil mixtures in diesel engine power plants. The objects of analysis is a power plant with electricity generation capacity (300 kW). Using performance data of original diesel engines, the fuel consumption characteristics of the duel fuel engines were simulated. Then, economic assessment was carried out using the performance data and the net present value method. A special focus was given to the evaluation of fuel cost saving when firing natural gas/diesel and natural gas/by-product oil mixtures instead of the pure diesel firing case. Analyses were performed by assuming fuel price changes in the market as well as by using current prices. The analysis results showed that co-firing of natural gas/diesel and natural gas/by-product oil would provide considerable fuel cost saving, leading to meaningful economic benefits.

• 한국응용곤충학회지
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• 제43권4호
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• pp.323-328
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• 2004

본 연구는 시설하우스의 주요 해충인 온실가루이와 담배가루이에 대한 spearmint oil의 훈증독성 및 접촉독성을 조사하였으며, gas chromatograph (GC)와 gas chromatograph mass spectrometry(GC/MS)를 이용하여 speamint oil의 주요 구성성분을 분석하였다. 훈증독성 시험 결과, 온실가루이에 대해서 spearmint oil은 $10{\mu}L/954mL$ air의 약량처리에서 $99.1\%$의 살충활성을 나타내었으며, 5와 $1{\mu}L/954mL$ air의 약량처리에서 각각 $91.7\%$와 $41.1\%$의 살충활성을 나타내었다. 또한 담배가루이에 대해서 spearmint oil은 $10{\mu}L/954mL$ air의 약량처리에서 각각 $100\%$의 살충활성을 나타내었으며, 5와 $1{\mu}L/954mL$ air의 약량에서도 각각 100, $61.3\%$의 높은 살충활성을 나타내었다. 그러나 온실가루이와 담배가루이 성충에 대한 spearmint oil의 접촉독성은 살충효과가 $30\%$ 이하로 낮았다. Spearmint oil을 GC와 GC/MS로 분석한 결과, limonene ($16.1\%$), ${\gamma}$-terpinene($13.8\%$), ${\rho}$-cymene($5.8\%$), 3-octanol($6.9\%$), carvone($40.9\%$)이 주요 구성성분으로 나타났으며, 주요성분인 carvone 은 $10{\mu}L/954mL$ air 약량에서 $100\%$의 높은 훈증독성을 나타내었다.

• Applied Biological Chemistry
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• 제35권1호
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• pp.36-41
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• 1992

면실유, 옥배유 및 채종유의 산패도를 신속하고 재현성 있게 측정하고자 $60^{\circ}C$ 및 $70^{\circ}C$로 저장한 식용유의 pentanal과 hexanal을 headspace 가스크로마토그라피 방법으로 분석하였고, 그 결과를 관능검사 결과와 상관분석을 실시하였다. Headspace 가스크로마토그라피 방법에서 휘발성 산화생성물의 포집 및 용출은 cold trap-thermal desorption 방법으로 실시하였으며, GC 주입부에 들어가는 splitless mode glass liner insert에 Tenax GC를 충전하여 사용하였다. 23종의 휘발성 산화생성물이 gas chromatography 및 gas chromatography-mass spectrometry에 의하여 검출되었으며, 저장 기간에 따른 pentanal과 hexanal 함량 변화와 관능검사에 의한 산패취 측정 결과의 상관분석을 실시한 결과, pentana(PE), hexanal(HE) 및 log{PE) log(HE) $log(PE){\times}log(HE)$의 세 가지를 변수로 한 회귀식의 상관계수의 값이 각각 0.831, 0.866 및 0.896으로 다같이 높을 값을 보였다. 따라서 headspace 가스크로마토그라피를 이용하여 면실유, 옥배유 및 채종유의 휘발성 산화생성물 중 pentanal과 hexanal을 분석하면 각각의 식용유의 산패도를 객관적으로 평가할 수 있음을 알 수 있었다.

• Journal of Nutrition and Health
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• 제16권2호
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• pp.107-114
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• 1983

There has been no specific test available for identifying the sesame oil among common edible oils. As the contents of sesamin and the ratio of sterols allowed the estimation for the genuine sesame oil, the author investigated to establish some instrumental methods for verification of genuine sesame oil and its distribution in the market. The sesame oil was saponified and the sesamin and sterols were isolated from the unsaponiable fraction by Florisil column chromatography. The individual components were determined by gas- chromatography and sesamin standard (purified sesamin) was obtained by silicagel column chromatography. The gas- chromatographic condition using Flame Ionization Detector supported on 10% OV-101 with di-(2-ethylhexyl) sebacate as an internal standard was suitable, and quantitation of sesamin and sterols, including campesterol, stigmasterol and ${\beta}-sitosterol$ was carried out. The results of this study showed that contents of sesamin in genuine sesame oil were 0.3-0.5% and the ratio of stigmasterol to compesterol was 0.3-0.6 and ${\beta}-sitosterol$ to campesterol 3.0-3.8. The 50 samples from the markets in Seoul were composed of 70% genuine sesame oil, and others were mixed with palm oil, rape seed oil and soybean oil.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.201-204
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• 2012

Combustion characteristics of boiler fuels made of bio-oil and light-oil were experimentally investigated. Bio-oil was obtained by fast pyrolysis of woody biomass. Emulsion fuel made by mixing bio-oil (up to 30wt%) with light-oil and surfactant was completely burnt, resulting in the formation of combusted gas containing CO concentration less than 10ppm. Simple mixtures of bio-oil and light-oil with separate delivery lines also gave nice combustion characteristics.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권8호
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• pp.343-349
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• 2005

The gas in oil analysis of transformer is the most widely used technology for diagnosis of transformer in the world. It has brought excellent results to prevention of transformer failure. The criteria for maintenance and judgement, however, is still required continuous supplement to improve the accuracy of the diagnosis on the basis of accumulated data of gas analysis and investigations in the transformer In this study, the relationship between the detection rate of the defects and the source of troubles are analyzed according to the investigation in the transformer, which was conducted by KEPCO in 2004. As a result, the validity of the criteria being used at present was examined thoroughly.

• 한국가스학회지
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• 제11권1호
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• pp.9-12
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• 2007

본 연구에서는 디젤기관에서 배출되는 배출가스의 저감을 위하여 경유와 천연가스의 혼합비율이 서로 다르게 연료의 분사량을 조절 전부하 운전시의 토크값을 4:0, 3:1, 2:2및 1:3의 4종류로 설정 디젤기관의 연소특성을 살펴보았다. 엔진회전수의 변화에 의한 배출가스의 변화를 알아보기 위하여 회전수를 1500, 2000, 2500 및 3000 rpm으로 설정 NOx, 흑연, 일산화탄소 및 탄화수소의 배출농도값을 측정하였다. 그 결과 디젤연료만을 사용하였을 경우보다 천연가스를 혼합하였을 경우 NOx, 일산화탄소 및 탄화수소의 배출농도는 다소 증가하였으나, 흑연의 배출농도는 감소하는 경향을 나타내었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.233-236
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• 2004

An experimental study was conducted to evaluate characteristic variation of diluted engine oil by diesel fuel and its effects on engine components. Especially, engine oil was made to have $15\%$ fuel content. To predict existing diesel fuel content in engine oil after test was used the viscosity calibration curve. About $54\%$ percent of diesel fuel in diluted engine oil was distillated by various paths related to reciprocating motion of piston and the rest diesel fuel plays an important role for decreasing engine oil viscosity. Test results show that lowered engine ell viscosity by diesel fuel dilution become a reason of increasing engine elements wear, Therefore, this caused the quantity of blow-by gas to increase and main gallery pressure to decrease.