• Applied Biological Chemistry
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• v.51 no.3
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• pp.177-182
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• 2008

This study was carried out to investigate the reaction of lipase-catalyst transesterification using animal fat recovered from fleshing scrap generated during leather making process. Transesterification reaction between fat and primary or secondary alcohol was carried out under the condition of immobilized enzyme catalyst. The conversion rate was the highest when 1.5 mole of methanol was injected by 4 times. As for lipase, Candida antarctica showed the highest conversion rate of 82.2% among the 4 different lipases. It was found that water contained in the fat causes lower conversion rate. The condition of 1.2wt. % of water in the fat decreased the conversion rate by 40%. It was considered that the resulted reactant, fatty acid ester could be used as raw material for biodiesel with the characteristics of not generating SOx and diminishing smoke.

• 한국벤처창업학회:학술대회논문집
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• 2017.04a
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• pp.35-35
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• 2017

이 연구의 목적은 온라인 판매에 집중하는 창업 기업들의 온라인 판매량 증진을 위해 구매 전환율에 영향을 미치는 요인을 확인하기 위한 것이다. 일반적으로 온라인 판매에 있어서는 네이버 및 다음 등 검색엔진 및 판매하는 마켓별로 CPC 또는 전시입찰 등의 광고를 집행을 통해 매출에 긍정적인 영향을 미친다고 알려졌으나, 최근에는 과다경쟁으로 인한 광고비의 집행비용의 인상율에 비해, 광고로 인한 판매율-구매전환율(ROAS)이 떨어짐을 확인되고 있어, 판매자들에게 혼란을 주고 있다. 매출 및 구매전환율을 늘리기 위한 효과적인 방법을 찾는 과정에서, 온라인 광고를 하면서도 그 외 요인들로 인해 경쟁사보다 판매량이 높은 상품들을 확인할 수 있었고, 소비자들에게 긍정적인 영향을 미치는 구매 단서를 통해 판매량에 긍정적 영향을 끼치는 것으로 보여, 연구를 하게 되었으며, 온라인 판매되는 상품들의 비교를 통해 가장 긍정적 영향을 미치는 요인을 확인하고자 한다. 또한, 수많은 상품들이 있는 온라인 시장에서 온라인 광고는 소비자들에게 자신의 상품이 노출되기 위한 필수불가결인 요소이나, 광고를 하면서도, 구매전환율(ROAS)을 높이기 위한 구매에 영향에 미치는 요인을 찾아, 온라인 판매 기업들의 효율을 높이기 위한 연구이다. 구매 전환율에 영향을 미치는 요인이 확인되었을 때, 해당 요인들에 집중하여, 결과적으로 판매량을 늘리고 매출을 높일 수 있을 것이다.

• The Korean Journal of Applied Statistics
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• v.21 no.5
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• pp.739-754
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• 2008

Researches on conversion formulas between multiple decrement models and the associated single decrement models have focused on calculating yearly-based conversion formulas. In practice, actuaries may be more interested in monthly-based conversion formulas. Multiple decrement tables and their associated single decrement tables consist of yearly-based rates of multiple decrements and absolute rates of decrements, respectively. This paper derives conversion formulas from yearly-based absolute rates of decrements to monthly-based rates of decrement due to cause j under the uniform distribution of decrements(UDD). Next, it suggests conversion formulas from monthly-based absolute rates of decrements to monthly-based rates of decrement due to cause j under UDD. In addition, it calculates conversion formulas from yearly-based rates of decrement due to cause j to the corresponding absolute rates of decrements under UDD or constant force assumption. Some numerical examples are discussed.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.245-253
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• 2020

If the conversion rate of jeonse price to monthly rent is the market interest rate or the landlord's expected return, then the conversion rate of jeonse price to monthly rent in the country should be the same. However, the conversion rate of jeonse price to monthly rent has always been higher than the market interest rate. This study identifies the supply cost components of rental housing as a risk premium in the presence of current housing prices, market interest rates, depreciation costs, holding taxes, and leases, and identifies the relationship between the current housing prices and each factor. Housing rent is expressed as the current price. This overcomes the shortcomings that implicitly assume fluctuations in housing prices or do not include current housing prices in the conversion rate of jeonse price to monthly rent. This study found that the conversion rate of jeonse price to monthly rent is the required rate of return or required rate of renter, not market interest rate, by expressing the supply cost of rental housing as a combination of components. This not only explained the fact that the conversion rate of jeonse price to monthly rent was always higher than the market interest rate, but also explained the regional differences. It also explained why the conversion rate of jeonse price to monthly rent varies by type of housing.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.50-56
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• 2003

Turnover rate of applied rice straw and rice straw compost in a rice paddy soil under the flooding and intermittent irrigation was studied. The chambers in duplicate were either planted or unplanted with rice. For planted chambers, the turnover rate to methane under the flooding increased with freshness of organic materials applied: 14.9% for RS5 (rice straw applied in May), 9.5 % for RS2 (rice straw incorporated in February), and 4.0% for RSC (rice straw compost amended in May). Similar trend was found in turnover rate to methane under the intermittent irrigation: 9.8% for RS5, 5.5% for RS2, and 2.1% for RSC. For planted chambers, turnover rate to methane under the flooding was generally 1.64 times higher than that under the intermittent irrigation. In contrast, for unplanted chambers, the turnover rate to methane under the flooding increased with freshness of organic materials applied: 8.7% for RS5, 3.3% for RS2, and 3.0% for RSC. Similar trend was observed in chambers under the intermittent irrigation: 5.4% for RS5, 3.0% for RS2, and 1.4% for RSC. For unplanted chambers, the turnover rate to methane under the flooding was generally 1.52 times higher than that under the intermittent irrigation.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.7-13
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• 1999

원형 용융탄산염 단위 연료전지의 성능 및 온도분포가 수치모사를 통해 얻어졌다. 원형 단위전지내에서는 사각형 단위전지에 비해 비교적 균일한 온도분포가 얻어졌다. 전지의 바깥쪽으로 갈수록 가스전환율이 커졌고 전류밀도도 크게 증가하였다. 운전전압이 감소할수록 각 가스들의 전환율은 커지고 전류밀도도 커졌다. 원형 전지에서의 평균전류밀도나 출력은 전압이 높을 때는 사각형 전지보다 작았고, 전압이 낮을 때는 더 컸다. 음극 및 양극 가스의 전환율도 마찬가지였다. 전압이 낮을 때 가스의 전환율이 커서 원형 전지의 효용성이 크게 나타났다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.447-450
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• 2009

2세대 바이오연료 생산에 적용되는 미세 조류의 열화학적 전환 특성을 열천칭 반응기를 이용하여 고찰하였다. 반응 온도 (500 - $800^{\circ}C$)와 수분 함량 (0-60wt.%)을 변수로 하였으며 미세조류로서 가장 널리 이용되는 클로렐라를 이용하였다. 대표적인 열화학적 전환 반응인 열분해, 부분 산화 (5%), 연소 반응을 고찰하였으며 실험 영역에서 반응온도 및 산소의 분압이 증가함에 따라 탄소 전환율이 증가하였으며 Shrinking-core model을 사용하여 반응 차수를 구하였다. 가스화 영역인 부분 산화 (5%) 조건에서의 activation energy와 frequency factor 값은 각각 19.60 kJ/mol, $2.47{\times}10-1\;s^{-1}$ 이었으며 산소 분압에 의한 반응 차수는 0.209 임을 확인하였다. 수분 함량에 따른 클로렐라의 반응 특성을 살펴보면, 수분 함량이 증가함에 따라 탄소 전환율과 반응성이 감소하는 경향이 발견되었다. 열분해의 경우, 건조 시료에 비하여 수분 함량이 늘어남에 따라 탄소 전환율과 반응성이 급격하게 감소하는 경향을 보였다. 반면, 부분 산화(5%) 및 연소의 경우에는 건조 시료, 수분 함량 20, 40% 시료의 탄소 전환율과 반응성은 거의 일정하였다. 그러나 수분 함량이 60%가 되면서 탄소 전환율 및 반응성이 급격히 떨어졌다.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.1977-1983
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• 2000

SCR(selective catalytic reduction) pilot plant for reduction of the nitrogen oxides using diesel oil as a reductant was installed at the NG(natural gas) fired combined cycle and the activity of Pt(0.3%)/Zeolite catalyst was studied in real flue gas condition according to the amount of reductant. reaction temperature and space velocity. NOx conversion gradually increased with increasing the diesel oil concentration up to C/N ratio 5.5(C/N ratio: the ratio of the number of carbon atom to the number of NOx molecules included in the flue gas). Increasing the reaction temperature. NOx conversion increased and reached a maximum conversion of 50% at $190^{\circ}C$. NOx conversion did not changed with increasing the space velocity up to 18,500/hr and then gradually decreased. These results reveal the potential for diesel oil as a reductant for de-NOx SCR process.

• The Korean Journal of Applied Statistics
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• v.21 no.6
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• pp.1045-1063
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• 2008

This paper derives conversion formulas from yearly-based absolute rates of decrements to monthly-based rates of decrement due to cause j under FI (fractional age independence) assumption that is a generalization of UDD assumption. Next, it suggests conversion formulas from monthly-based absoluterates of decrements to monthly-based rates of decrement due to cause j under FI assumption. In addition, it calculates conversion formulas from yearly-based rates of decrement due to cause j to the corresponding monthly-based absolute rates of decrements under FI assumption. Some numerical examples are discussed.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.385-394
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• 1994

Numerical solutions were obtained to the model equations for various of the parameters characterizing the pore structure, effective internal diffusion, and the chemical reaction constant. The conversion was decreased with the cause of pore closure at the surface of reacting particles, reduction of porosity, surface area of reaction and effective diffusion coefficient in the solid with the progress of reaction. Total conversion was strongly dependent on the local conversion at surface. According to the decreasing of impregnated concentration of the copper oxide and the increase of the flue gases concentration, total conversion was increased. The conversion was affected by gas flow rate and pore size distribution in the reacting solid.