http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
DME 연료 디젤엔진의 연소 및 공해물질 배출 특성 해석
유용욱 ( Yong Wook Yu ),이정원 ( Jeong Won Lee ),김용모 ( Yong Mo Kim ) 한국액체미립화학회 2008 한국액체미립화학회지 Vol.13 No.1
The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure diesel engines. In order to realistically simulate the dimethyl ether (DME) fueled diesel engine, the high pressure vaporization model is utilized and the interaction between turbulence and chemistry is treated by employing the Representative Interactive Flamelet (RIF) model. The detailed chemisty consisted of 336 elementary reaction steps and 78 species is used for DME/air reaction. Numerical results indicate that the RIF model with high pressure vaporization model successfully predicts the essential feature of the combustion processes and pollutants formations in the DME fueled diesel engines.
유용욱(Yong-Wook Yu),이정원(Jeong-Won Lee),김용모(Yongmo Kim) 한국연소학회 2007 한국연소학회지 Vol.12 No.3
The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure engine conditions. In order to realistically simulate the dimethyl ether (DME) spray dynamics and vaporization characteristics in high-pressure and high-temperature environment, the high-pressure vaporization model is utilized. The interaction between chemistry and turbulence is treated by employing the Representative Interaction Flamelet (RIF) model. The detailed chemistry of 336 elementary steps and 78 chemical species is used for the DME/air reaction. Numerical results indicate that the RIF approach, together with the high-pressure vaporization model, successfully predicts the essential feature of ignition and spray combustion processes.
Prevotella nigrescens의 용혈특성에 관한 연구
곽주석,장훈상,장석우,이수종,유용욱,민경산 大韓齒科保存學會 2005 Restorative Dentistry & Endodontics Vol.30 No.4
세균의 용혈활성은 세균이 숙주 내에서 생존하기 위해 필요한 철을 획득하기위한 특성이며 기능면에서 볼 때 숙주에 대한 중요한 독력인자로 간주될 수 있다. 본 연구에서는 괴사치수 및 치근단 치주염으로 진단된 환자의 근관에서 분리한 Prevotella nigrescens의 용혈활성을 다양한 조건 하에서 측정하여 그 특성을 규명하는 것을 목적으로 한다. 1. 임상에서 분리한 P. nigrescers와 표준균주인 P. nigrescers ATCC 33563에서 모두 용혈활성이 나타났다. 2. 사람, 면양 및 말 세 가지 종에 대해 용혈활성을 비교한 결과 사람의 적혈구에서 가장 강한 용혈활성을 나타내었다. 3. 용혈소 억제제인 NaN₃와 dithiothreitol (DTT)는 농도의존적으로 P.nigrescers의 용혈활성을 감소시켰다 (p<0.05). 4. P. nigrescers가 최대 용혈활성을 나타내는 최적의 pH는 4이었으며, 50℃이하의 온도에서는 용혈활성을 보였으나 95℃에서 급격히 감소하였다. 5.배양조건에 따른 P. nigrescens의 용혈활성을비교한 결과 10% CO₂배양기에 배양한 경우혐기성 조건에서 배양한 것보다 더 높은 용혈활성을 보였다. Hemolytic property is a specific feature of bacteria to obtain iron which is essential for its survival in host tissues. Therefore, it is thought to be one of several factors of virulence. The purpose of this study was to investigate the hemolytic properties of Prevotella nigrescens isolated from the teeth diagnosed as pulp necrosis and apical periodontitis under the presence of hemolysin inhibitors such as NaN3 and dithiothreitol, heat, various pH and cultural conditions. The results were as follows; 1. Clinically isolated P. nigrescens strains and standard P. nigrscens ATCC 33563 showed hemolytic activity. 2. P. nigrescens showed higher hemolytic activity against human erythrocytes than sheep or horse erythrocytes. 3. NaN₃ and dithiothreitol (DTT) reduced the hemolytic activity of P. nigrescens in a dose dependent manner (p<0.05). 4. Optimal pH for the maximum hemolytic activity of P. nigrescens was 4.0 and the hemolysin was stable under the 50℃, but the hemolytic activity was significantly decreased at 95℃. 5. P. nigrescens cultured in 10% CO₂ condition showed higher hemolytic activity than the bacteria cultured in the anaerobic condition.[J Kor Acad Cons Dent 30(4):335-343,2005]