• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.37-43
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• 2012

We were studied that AZO conductive thin film can substitute for FTO electrode in dye sensitized solar cell. Three types of AZO films were deposited on soda-lime glass(AZO/glass, AZO/AZO/glass, textured AZO/AZO/glass) using RF magnetron sputtering process and investigated their properties of electrical, optical, and photoelectric conversion rate. The textured AZO/AZO/glass has the lowest resistivity of $3.079{\times}10^{-4}\;{\Omega}cm$ among other films. And the optical transmittance rate was better than both non textured AZO/AZO/glass and FTO/glass in the visible region. After manufacturing dye solar cells using the three types of AZO films, the textured AZO/AZO/glass showed the highest photoelectric conversion rate of 3.68% among AZO samples. But the transformation rate was slightly lower than FTO cells (4.52%). However, the conductive film of textured AZO/AZO/glass can be applicable to use an electrode in solar cells as cost-effective products.

• 한국연소학회지
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• 제20권3호
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• pp.35-42
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• 2015

Investigating coal combustion in a large-scale boiler using computational fluid dynamics (CFD) requires a combination of flow and reaction models. These models include a number of rate constants which are often difficult to determine or validate for particular coals or furnaces. Nonetheless, CFD plays an important role in developing new combustion technologies and improving the operation. In this study, the model selection and rate constants for coal devolatilization, char conversion, and turbulent reaction were evaluated for a commercial wall-firing boiler. The influence of devolatilization and char reaction models was found not significant on the overall temperature distribution and heat transfer rate. However, the difference in the flame shapes near the burners were noticeable. Compared to the coal conversion models, the rate constant used for the eddy dissipation rate of gaseous reactions had a larger influence on the temperature and heat transfer rate. Based on the operation data, a value for the rate constant was recommended.

• Elastomers and Composites
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• 제14권4호
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• pp.231-252
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• 1979

Polymerization of 2-pyrrolidone was carried out through anionic mechanism using $SO_2/KOH$ as catalyst. The effects of KOH concentration, $SO_2/KOH$ mole ratio and temperature on polymerization were investigated. The conversion and viscosity of polymers were measured at various polymerization conditions. It was observed that as the concentration of KOH was increased, equilibrium conversion was also increased. It was, however, found that after the concentration of KOH was reached above 8 mole percent, the equilibrium conversion was decreased. The highest rate of polymerization and maximum conversion were obtained when $SO_2/KOH$ mole ratio was around 0.5. It was also found that the rate of polymerization and the equilibrium conversion were higher at $50^{\circ}C$. than at $30^{\circ}C$. but the viscosity of polymer solution at $50^{\circ}C$. was not so high as expected. The rate constant, $K_p$ of polymerization, was determined by least square method: the value of $K_p$ was observed as 16 liter/mole hour at $50^{\circ}C$. and 2.6 liter/mole hour at $30^{\circ}C$., respectively. The mechanism of polymerization was also discussed.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.329-332
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• 2001

It has been known that, in enzymatic synthesis of cephalexin, the conversion yield was reduced by high loading of ampicillin acylase. In order to elucidate this phenomena, pH-controlled synthesis of cephalexin was examined using a purified Acetobacter turbidans acylase. When the pH of the reaction mixture was maintained at $6.20{\pm}0.04$, the reduction of the maximal conversion rate was not observed even with high enzyme loading. The kinetic parameters also suggest that pH drop during the enzymatic synthesis of cephalexin was mainly attributed to the rapid hydrolysis of D-${\alpha}$-phenylglycine methyl ester to D-${\alpha}$-phenylglycine, rather than the disappearance of 7-amino-3-deacetoxycephalosporanic acid for cephalexin synthesis. At higher molar ratio of two substrates, [D-${\alpha}$-phenylglycine methyl ester]/[7-amino-3-deacetoxycephalosporanic acid], the conversion rate was also elevated under pH-controlled enzymatic synthesis, which implies that the main reason for the pH drop is due to the production of D-${\alpha}$-phenylglycine methyl easter, the effect of a water-methanol cosolvent system on the ester, the effect of a water-methanol cosolvent system on the conversion profile was also examined. Even the though the conversion rate was increased in 10% methanol solution, a higher than 16% methanol in the reaction mixture caused an inactivation of enzyme.

• Restorative Dentistry and Endodontics
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• 제27권1호
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• pp.16-23
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• 2002

Physical properties of composite resins such as strength, resistance to wear, discoloration, etc depend on the degree of conversion of the resin components. The purpose of this study was to evaluate the degree of conversion of the composite resins according to the thickness of tooth structure penetrated by light and applied light curing time. The coronal portions of extracted human teeth (one anterior tooth, three posterior tooth) was embedded by pink denture material. the mounted teeth were cut into three illumination sections (1mm thickness enamel section, 1mm thickness dentin section, 2mm thicknes dentin section) and one backing section with cutting wheel. Thin resin films were made by using 6kg pressure between slide glass during 5 minutes Thin resin film was light cured on coupled illumination section during 40sec, 80sec and 120sec. each illumination section was coupled as follows; no tooth structure(X), ename section(E), enamel section + 1mm dentin section(ED1), enamel section + 2mm dentin section(ED2), enamel section + 1mm dentin section + 2mm dentin section(EDD). To simulate the clinical situation more closely, thin resin films was cured against a backing section of tooth structure. The degree of conversion of carbon double bonds to single bonds in the resin films were examined by means of Fourier Transform Infrared Spectrometer. The results were obtained as follows ; 1 As curing time was increased, conversion rate was increased and as tooth thickness which was penetrated by curing light was increased, conversion rate was decreased. 2. At all tooth thickness groups, conversion rate between 80sec and 120sec was not significantly increased(P＞0.05). 3. At 40sec group and 80sec, conversion rate between no tooth structure(X) group and 1mm enamel section(E) group was not significantly decreased(P＞0.05). 4. At 80sec group and 120sec, conversion rate between 1mm enamel section(E) group and 1mm enamel section + 1mm dentin section(ED1) group was not significantly decreased(P＞0.05).

• 한국축산시설환경학회지
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• 제18권2호
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• pp.63-74
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• 2012

사육밀도의 차이가 지렁이의 생육, 체조직으로의 유기물 전환효율 및 분립생산량에 미치는 영향을 조사한 결과를 요약하면 다음과 같다. 1. 공시 한우분의 탄질율은 25.1로, 지렁이 먹이로 적합한 탄질율로 추정되었다. 2. 지렁이 생체중과 먹이 량의 비율이 1:32였던 S-3에서 생체중 증가율과 체조직으로의 유기물 전환효율이 유의하게 높은 값을 나타내었는데, 이 비율을 사육공간으로 나타내면 $56.6cm^3$이었다. S-3에서 사육기간 평균 생체중 증가율과 체조직으로의 유기물 전환효율은 각각 10.63 mg/day와 6.65%를 나타내었다. 3. 지렁이 생체중과 먹이 량의 비율 1:8이었던 S-1에서 사육기간 중 분립비율이 가장 높았지만, 생체중 증가율과 체조직으로 유기물 전환효은 -값을 나타내었다. 이는 개체 간 먹이 경합이 심해진 결과로 추정된다. 4. 사육밀도가 높아짐에 따라 지렁이 분립의 pH, 전 질소함량, 유효인산함량, 양이온치환능력 (CEC) 및 양이온 함량이 유의하게 증가되었다. 특히 유효인산함량, 양이온치환능력 및 양이온함량은 사육기간이 길어짐에 따라 유의하게 증가되었다. 5. 지렁이 분립의 이화학적 특성으로 볼 때, 상토 재 또는 토양개량제로서 유용성이 높다고 판단되었다.

• 품질경영학회지
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• 제37권3호
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• pp.74-82
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• 2009

This article presents a six sigma project for improving purchase conversion rate in mobile game site. The project was carried out based on DMAIC process. First, a defect rate is defined as low purchase conversion rate. In addition, 60-days purchase data was analyzed and it is shown that the defects level was 2.48 sigma level. In this study, in order to raise the sigma level, six personalization services were used in the mobile game site. Six factors were determined based on FDPM(Functional Deployment Process Map), fishbone chart, linear regression analysis, effort-performance matrix, and so on. The sigma level of defects has improved from 2.48 to 2.93.

• 대한전자공학회논문지SP
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• 제47권4호
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• pp.1-8
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• 2010

본 논문에서는 효과적인 프레임율 증가 변환을 위한 새로운 방법을 제안하였다. 첫 번째로 제안한 삼중 프레임 기반의 양방향 움직임 추정 방법은 기존의 양방향 움직임 추정 방법에서 발생한 문제점인 유사한 특성을 갖는 이미지에서의 잘못된 움직임 추정을 해결하여 보간 프레임 생성 시 발생한 블록화 현상을 크게 줄일 수 있었다. 두 번째로 제안한 움직임 벡터 평탄화 방법은 시공간적으로 인접한 움직임 벡터들을 고려하여 블록화 현상의 원인이 되는 아웃라이어를 제거할 수 있었다. 실험 결과 제안한 프레임율 증가 변환 방법은 기존의 방법들과 비교했을 때 평균 PSNR이 최대 4.337 dB만큼 높은 것을 확인할 수 있었고, 평균 SSIM은 최대 0.089만큼 높은 것을 확인할 수 있었다.

• 한국응용과학기술학회지
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• 제26권4호
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• pp.394-399
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• 2009

The esterification of palmitic acid in Jatropha Oil using 8wt% p-TSA catalyst was done at the 1:8 molar ratio of oil to methanol and $65^{\circ}C$. The conversion of palmitic acid appeared to be 95.3% in 60min. After that, the continuous transesterification of the oil using 0.5wt% KOH, 0.8wt% TMAH mixed catalyst[40vol% KOH(0.5wt%) + 60vol% TMAH(0.8wt%)] and 1.1wt% TMAH was conducted with the flow rates and the molar ratios at $65^{\circ}C$. The overall conversion of Jatropha Oil increased with the decrease of flow rate and showed 95.6% with 9ml/min of flow rate at the 1:8 molar ratio of oil to methanol and $65^{\circ}C$. But it showed 87% with 15ml/min of flow rate at the same conditions. The recovery of methanol(%) appeared to be 86% at the 1:8 molar ratio of oil to methanol, mixed catalyst and $65^{\circ}C$.

• 한국기계기술학회지
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• 제13권2호
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• pp.123-128
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• 2011

It has been stand high in estimation to converse from Carbon dioxide to Dimethyl Ether in new alternative fuel energy division in 21C, especially Using of DME in point of view of transportation fuel has been discussed of a new clean energy which is very lower of exhaust gas than gasoline and diesel energy. In this paper it is used ZSM-5 and I developed new catalyst by addition of cerium to control acidity. The new catalyst was proved high conversion rate, when it was conversed from methanol to DME, there wasn't any additional material except DME and water, and I overlooked reaction temperature, reaction time, amount of catalyst, amount of added cerium, effect of water content in methanol, reaction temperature by making change of reaction time. I have conclude that conversion rate to DME was increased as increased of catalyst amounts. The best catalyst condition of without additional product was treated poisoning from ZSM-5 to 5% cerium and new catalyst was not effected in purity of fuel methanol.