• 한국자동차공학회논문집
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• 제11권3호
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• pp.85-91
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• 2003

In this study, the potential possibility of oxygenated fuel such as Methyl tertiary butyl ether (MTBE) was investigated for the sake of exhausted smoke reduction from diesel engine. MTBE has been used as a fuel additive blended into unleaded gasoline to improve octane number, but the study of application for diesel engine was incomplete. Because MTBE includes oxygen content approximately 18%, it is a kind of oxygenated fuel that the smoke emission of MTBE is reduced remarkably compared with commercial diesel fuel. But, the NOx emission of MTBE blended fuel is increased compared with commercial diesel fuel. And, it was tried to analyze not only total hydrocarbon but individual hydrocarbon components from $C_1$ to $C_6$ in exhaust gas using gas chromatography to seek the reason for remarkable reduction of smoke emission. Individual hydrocarbons($C_1$~$C_6$) as well as total hydrocarbon of oxygenated fuel are reduced remarkably compared with diesel fuel. And, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission has been investigated, too. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel and cooled EGR method.

• 대한간호학회지
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• 제43권3호
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• pp.305-311
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• 2013

Purpose: The purpose of this study was to compare the effect of alcohol gel according to the amount and drying time in health personnel hand hygiene and to promote in their practice adequate and effective hand hygiene. Methods: The crossover experimental study was performed with 14 volunteers. Hands were artificially contaminated with 5 mL of $10^8$ CFU/mL of Serratia marcescens (ATCC 14756) and four different alcohol gel hand hygiene methods varying by the amount of alcohol gel (2 mL vs. 1 mL) and drying time (complete vs. incomplete) were compared. Samples were collected by glove juice sampling procedures. Results: Mean log reduction values of the four different hand hygiene methods were $2.22{\pm}0.36$, $1.26{\pm}0.53$, $1.49{\pm}0.60$, $0.89{\pm}0.47$ respectively for the 4 groups: adequate amount (2mL) and complete dry (30 seconds rubbing followed by 2 min air-dry), inadequate amount (1 mL) and complete dry, adequate amount and incomplete dry (15 seconds rubbing and no air-dry), and inadequate amount and incomplete dry. The difference was statistically significant in the adequate amount and complete dry group compared to other three groups (p<.001). Conclusion: Only alcohol gel hand hygiene with adequate amount and complete drying was satisfactory by U.S. FDA-TFM efficacy requirements for antiseptic hand hygiene products.

• 기술사
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• 제34권4호
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• pp.69-73
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• 2001

Due to the rapid increase of automobiles and daily driving distances, air pollution by automobiles is still dominant problem of large city in spite of strict emission refutation and development of reduction technologies. Among the air pollution resources of automobile , industry. electricity generation and heating. automobile keeps 51% of total nationwide air pollution in 1998 and this proportion Is increasing in large cities from 65% to 85%. To reduce these air pollution. catalytic converter and electronic engine control, exhaust gas re-circulation and evaporative emission control system have continuously developed and applied to automobiles since 1987. Also strong emission standards and emission durability warranty have enforced and monitored annually by sampling several vehicle models. But technologies and regulations are incomplete, driver should participate in reducing air pollution for himself by planning driving, avoiding unnecessary idle and air conditioning, keeping periodic maintenance and using mass transportation.

• 동력기계공학회지
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• 제3권2호
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• pp.20-25
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• 1999

Experiments were carried out to investigate the characteristics of formaldehyde emission from the small gasoline engine and its reduction technologies. Catalytic converters used are Pt/Rh, Pd/Rh, Pd/Pt, $62cell/cm^2$ monolith type. The measurement of formaldehyde was conducted by using the method of DNPH-GC. From the experimental results, formaldehyde emission increased in a lean mixture due to incomplete combustion of the hydrocarbons. The order of catalytic activity of formaldehyde oxidation was Pt/Rh > Pd/Rh > Pd/Pt. As the distance from the exhaust manifold to the inlet of the catalyst became far, in spite of lower catalyst temperature, formaldehyde concentration decreased because of the adsorption of formaldehyde.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.90-93
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• 2003

Sampling of waters from each stage of treatment system, SAPS (Successive Alkalinity Producing System), and spring water near the Hanchang coal mine of Kangwon. Province were carried out periodically and analyzed to evaluate the source and possible path of groundwater contamination by acid mine drainage(AMD). Chemical and sulfur isotope compositions showed that spring water was affected by seepage from mine tailings, and seepage of stonewall, a part of treatment system, was affected by both seepage from mine tailings and mine adit drainage. Through the treatment system no appreciable decrease of sulfur content was identified. And almost similar sulfur isotope compositions of water from each stage of the treatment system may suggest incomplete or very poor sulfate reduction by sulfate reducing bacteria.

• 통합자연과학논문집
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• 제5권2호
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• pp.135-138
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• 2012

The reduction of efficiency of missing observations on complete diallel cross designs are examined. we studies robustness of optimal block designs for estimating general combining ability against loss of missing observations in diallel cross. A-efficiencies suggest that these designs are fairly robust. Simple g-inverses may be found for the information matrices of the line effects which allow evaluation of expressions for the variances of the differences between the pairs of line effects with missing observations. we numerically calculate the reduction of efficiency for estimating general combining ability against loss of missing observations in diallel cross.

• 한국인터넷방송통신학회논문지
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• 제14권2호
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• pp.107-113
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• 2014

러프집합에서 식별불능의 관계와 근사공간의 개념을 이용해서 의사결정표로부터 최적화된 정보를 유도하게 된다. 그러나 일반적으로 결정표에서 데이터의 중복이나 비일관성은 피할 수 없기 때문에 속성의 중요성은 지식의 감축에서 매우 중요한 개념이다. 속성의 중요성에 대한 대수학적인 정의는 도메인중의 완전한 부분집합에 대한 해당 속성이 주는 영향을 고려하는 것이고, 정보이론적인 정의는 도메인 중의 불완전한 부분집합에 대한 해당 속성이 주는 영향을 고려하는 것이다. 따라서 속성 중요성은 정보이론적인 관점의 정의와 대수학인 관점의 정의가 분명하게 차이가 있다. 본 논문에서는 정보시스템의 조건속성과 결정속성에 포함될 수 있는 정보를 최적화하기 위한 정보이론적인 척도로써 러프집합을 이용한 조건부 정보엔트로피를 제안하고 그 효용성을 보인다.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.85-90
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• 2010

As the environmental regulation of vehicle emission is strengthened, investigations for $NO_x$ and PM reduction strategies are popularly conducted. Two current available technologies for continuous $NO_x$ reduction onboard diesel vehicles are Selective Catalytic Reduction (SCR) using aqueous urea and lean $NO_x$ trap (LNT) catalysts. The experiments were conducted to investigate the $NO_x$ reduction performance of SCR system which can control the ratio of $NO/NO_2$, temperature and SV(space velocity), and the model gas was used which is similar to a diesel exhaust gas. The maximum reduction efficiency is indicated when the $NO:NO_2$ ratio is 1:1 and the SV is 30,000 $h^{-1}$ in $300^{\circ}C$. Generally, ammonia slip from SCR reactors are rooted to incomplete conversion of $NH_3$ over the SCR. In this research, slip was occurred in 6cases (except low SV and $NO:NO_2$ ratio is 1:1) after SCR. Among 6 case of slip occurrence, the maximum conversion efficiency is observed when SV is 60,000 $h^{-1}$ in $400^{\circ}C$.

• 한국인터넷방송통신학회논문지
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• 제14권6호
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• pp.47-54
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• 2014

러프집합을 구성하는 식별불가능 관계를 표현하는 정보시스템에서 데이터의 중복이나 비일관성은 피할 수 없기 때문에 속성의 감축은 매우 중요하다. 러프집합이론에 있어서 일관적인 정보시스템과 비일관적인 정보시스템의 속성감축의 차이를 극복하고 자, 본 연구에서는 조건 및 결정속성에 대한 상관분석에 베이지언 사후확률을 적용한 새로운 불확실성 척도와 속성감축 알고리즘을 제안한다. 정보시스템의 불확실성에 대하여 제안된 척도와 기존의 조건부 정보엔트로피 척도를 비교해 본 결과, 정보시스템의 조건속성과 결정속성의 상호정보를 이용하여 속성간의 불확실성을 측정하는데 있어 제안된 방법이 조건부 정보엔트로피에 의한 방법보다 정확성이 있음을 보여준다.

• 약학회지
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• 제43권6호
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• pp.851-860
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• 1999

The effects of antimycin A(AA), dodium azide ($NaN_3$) and 2,4-dinitrophenol (DNP), which inhibit mitochondrial ATP production, on cellular functions of cultured astrocytes were studied. High concentrations of AA $(50{\;}\mu\textrm{g}/ml),{\;}NaN_3$ (100mM) and DNP (20mM) significantly decreased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction, which was known to be related to mitochondrial function and then cel viability. AA ($50{\;}\mu\textrm{g}/ml$) increased lactate dehydrogenase (LDH) release and decreased [$^3H$] glutamate uptake, suggesting severe damage of cellular function by the concentrations of the compounds. Meanwhile, low concentrations of AA $(\leq{;\}10{\;}\mu\textrm{g}/ml),{\;}NaN_3{;\}(\leq{\;}50mM)$ and DNP ($\leq{\;}5mM$) significantly increased MTT reduction, the effect of which was specific to astrocytes. AA (5 and $10{\;}\mu\textrm{g}/ml$) did not affect LDH release and [$^3H$] glutamate uptake, indicating that these compounds increased MTT reduction at the low concentrations without cellular membrane damage. However, the low concentrations of AA produced significant decrease of MTT reduction in a glucose-free medium. Low concentrations of AA (1 and $5{\;}\mu\textrm{g}/ml$) did not change ATP production of astrocytes in the medium containing 10 mM glucose, but completely inhibited in a glucose-free medium, suggesting marked increase of cytosolic ATP production by the blockade of mitochondrial ATP production with low concentrations of AA. These results suggest that astrocytes have ability to enhance neuronal function or survival under conditions of incomplete ischemia or early by enhancement of glycolysis, and that cellular reduction of MTT occurs not only mitochondrially but also extramitchondrially.