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대체 연료인 DME 혼합에 의한 대향류 에틸렌 확산화염내 매연 생성에 대한 실험적 연구
윤두호,윤석훈,최재혁,Yoon, Doo-Ho,Yoon, Seok-Hun,Choi, Jae-Hyuk 해양환경안전학회 2010 해양환경안전학회지 Vol.16 No.3
DME는 환경 친화적인 특성으로 인해 현재 전 세계적으로 주목을 받고 있다. 지금까지 DME는 매연을 적게 생산하는 청정 에너지라는 특성으로 인해 디젤 자동차의 주요 대체 에너지로서 연구되어 왔다. 이에 본 연구에서는 에틸렌 대향류 확산화염에 DME를 5%, 14% 및 30% 혼합했을 때, DME의 혼합 비율에 따른 매연의 수밀도 및 크기에 대한 영향을 조사하였다. 레이저 투과법 및 산란법을 이용해 수밀도 및 크기를 측정하였다. 그 결과 DME를 30% 혼합한 경우에는 매연이 감소한 반면, 5%와 14%의 혼합 비율에서는 매연이 증가하는 경향을 나타내었다. 이 결과는 DME가 매연 생성이 적은 청정 연료로 알려진 것과는 달리 에틸렌 확산화염 내에서는 DME의 혼합에 따라 매연 생성이 증가될 수 있다는 것을 의미한다. DME(Di-Methyl Ehter, $CH_3OCH$) is currently attracting worldwide attention due to its environmentally friendly characteristics. Until now it was researched as a major alternative fuel of diesel automobile because it is a clean fuel producing low soot. Therefore, in this study, in order to investigate the effect of DME mixing on number density and size of soot particle, DME has been mixed in opposed-flow ethylene diffusion flame with the mixture ratios 5%, 14% and 30%. A laser extinction/scattering technique has been adopted to measure the volume fraction, number density, and size of soot particles. The experimental results showed that the soot concentration of mixture flames with the mixture ratios 5% and 14% produces soot more, even though that of 30% was decreased. This means that even though DME has been known to be a clean fuel for soot formation, the mixing of DME in diffusion flame of ethylene, where acetylene maintains high concentration in soot formation regions, could produce enhanced production of soot.
윤두호,오철,윤석훈,Yoon, D.H.,Oh, C.,Yoon, S.H. 한국마린엔지니어링학회 2000 한국마린엔지니어링학회지 Vol.24 No.5
In this paper, experiments investigating the high-temperature region heat transfer coefficients for the spray cooling of hot flat plates were performed by down spray water using flat spray nozzles. The heat transfer surface is made of copper and is 100mm in length and 40mm in width and 15mm in thickness. The experimental condition of spray are as follows: temperatures of the water droplets are T=20~$80^{\circ}C$ and droplets volume fluxes are D=0.001565~0.010438$m^3/m^2s$. Next, correlating equations for the heat transfer characteristics of spray cooling in the high temperature region are developed from the effects of droplets volume flux and the surface temperature of heat transfer plate.
고온 열전달면의 각도에 따른 분무냉각 특성에 관한 연구
윤두호,오철,윤석훈,Yoon, D.H.,Oh, C.,Yoon, S.H. 한국마린엔지니어링학회 2002 한국마린엔지니어링학회지 Vol.26 No.3
An experimental study of heat transfer from hot flat surface to water sprays was conducted in high temperature region. Heat transfer measurements for hot flat surface were made by 4 sheathed C-A thermocouples. Droplets volume flux were also measured-independently at a position in spray field. The test conditions included variations in droplets volume flux, subcooling of cooling water of $1.565\times10^{-3} to 14.089\times10^{-3}m^3/m^2s and 80 to $20^{\circ}C$ respectively. The effects of inclination angle on heat transfer were investigated and changes in inclination angle of hot flat surface affected heat transfer coefficients of high temperature region.
윤두호(Doo-Ho Yun),이인회(In-Hoi Lee) 제주대학교 관광과경영경제연구소 2019 産經論集 Vol.39 No.4
Purpose - The outcomes of school education are more successful when unit schools’ educational capacities and the support and appropriate intervention of educational administration institutions coexist. Therefore, the necessity of restructuring the local educational administration institutions in the macroscopic and microscopic aspects is emphasized. Therefore, the purpose of this study was to explore the restructuring directions of Jeju Educational Organizations to vitalize Industrial Education in the era of fourth industrial revolution. Research design, data and methodology - For the study literature review and depth interview were employed. First, for literature research, previous studies on the reorganization of schools and educational administrative organizations, data on the reorganization of Jeju Special Self-Governing Provincial Office of Education, and the trends of reorganization of educational support offices and support works of other cities’ offices of education were analyzed. For interview surveys, in-depth interviews were conducted with persons concerned with Jeju Special Self-Governing Provincial Office of Education and persons concerned with educational support offices Result - The municipal and provincial offices of education and educational support offices insisted on the establishment and operation of school districts. The educational support offices presented improvement plans that will enable them to provide efficient administrative services and insisted on the separation or new establishment of large-scaled educational support offices. They proposed to restructure the organization and works of educational support offices. In addition, they suggested that organizations dedicated to school support should be newly established. Conclusion - The major results are as follows: First, the school district system (SDS) should be established successfully. To accomplish the goal, the professional learning community need to be ran prior to establishing the SDS, autonomy of administration, finance and communication in the SDS be increased, and interdependent support system between the current educationcentered system and the SDS be implemented. Second, the school organizations should be reorganized successfully in order to vitalize Industrial Education. To do so, all the stakeholder of schools need to build school culture for Industrial Education vitalization by sharing the student growth-centered vision, reinforce collective responsibility, and renew the role of a principal and a vice principal in each school.
손가락기능운동 프로그램이 여성노인의 인지능력과 주의집중력에 미치는 영향
윤두호(Doo-Ho Yoon),이혜윤(Hye-Yoon Lee),김경래(Kyeong-Lae Kim) 한국교원대학교 뇌기반교육연구소 2020 Brain, Digital, & Learning Vol.10 No.4
The purpose of this study is to investigate the effects of the finger function exercise programs on cognitive ability and attention of the elderly women. In order to accomplish the purpose of this study, 9 elderly women of exercise group and 12 of comparison group were selected from among women over the age of 65 who belong to the Senior Citizens’ Association of D city, and cognitive ability and attention of which were measured before and after participating in the exercise programs(performed 3 times a week for 12 weeks). The exercise program, which was conducted on women aged over 65 years for 12 weeks, had a positive effect on cognitive improvement. There were significant differences in the ‘K-MMSE total score, orientation (time), attention and calculation’. The Finger Function Exercise Program had a positive effect on improving attention. Significant differences shown in the all three Cancellation tasks of ‘character, number and symbol’, with greater variation in the exercise group. In conclusion, the 12-week program of Finger Function Exercise Program has contributed to the improvement of cognitive and attention of women aged over 65 years. We suggest that the results of this study provide some data needed to prevent and delay dementia in the elderly and improve brain health.
대형디젤기관에서의 연속재생방식 DPF와 Cooled EGR 성능
윤두호(Du-Ho Yun),문병철(M.B.Chul),오상기(Sang Ki Oh),백두성(Do Sung Baik),한영출(Young-Chool Han) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The world is faced against the serious problems related to the increasing air pollutions. This research focused on the principle and the development of continuous regeneration DPF and cooled EGR technology which were the after-treatment technologies due to its superior comparability ad possible applicability. The test was done on an 8000cc heavy-duty turbo diesel engine on which continuous regeneration DPF was installed in order to investigate regeneration characteristics of DPF and cooled EGR and engine performance under several conditions of standard diesel or 50ppm ultra low sulfur diesel. Besides exhaust emissions, CO, HC and PM were tested under D-13 mode.