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SI 기관에서 초기 화염의 생성 및 성장에 대한 모델링
송정훈,선우명호,Song, Jeonghoon,Sunwoo, Myoungho 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.2
In spark ignited engines, the electrical spark not only sets the time for the onset of combustion but also is able to greatly influence the character of the initial flame growth and the subsequent combustion, and thereby can influence engine performance. The relative importance of the ignition energy is particularly high under lean or high residual gas or exhaust gas recirculation (EGR). In this study, a modeling of flame Initiation and its development is proposed. Submodels consist in representing of cylinder pressure and temperature, heat transfer to cylinder wall, and flame kernel heat transfer to ambient air and to spark plug electrodes. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy, and laminar and turbulent flame velocity.
정적연소기에서 점화장치가 열발생률과 잘량연소율에 미치는 영향에 관한 연구
송정훈,이기형,선우명호,Song, Jeong-Hun,Lee, Gi-Hyeong 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.11
The initial flame kernel development and flame propagation in a constant volume combustion chamber is analyzed by the heat release rate and the mass fraction burnt. The combustion pressure is measured with a piezoelectric type pressure sensor. In order to evaluate the effects of ignition system and ignition energy on the flame propagation, four different ignition systems are designed and tested, and the ignition energy is varied by the dwell time. Several different spark plugs are also tested and examined to analysis the effects of electrodes on flame kernel development. The results show that the when the dwell time is increased, and when the spark plug gap is extended, heat release rate and the mass burnt fraction are increased. The materials and shapes of electrodes affect the flame development, because they change the energy transfer efficiency from electrical energy to chemical energy. The diameter of electrodes influences not only the heat release rate but also the mass burnt fraction as well.
송정훈,박종진,Song, Jung-Hoon,Park, Jong-Jin 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.11
Compared to a full three dimensional FEM, the Slab-FEM hybrid method reduces the required computation time distinctly and it can be applied to the analysis of a shape rolling process. However, the method is somewhat approximate and predictions by the method contain certain inaccuracies. In the present investigation a parameter called T-factor was introduced to compensate the inaccuracies of the method and proper values of the parameter were estimated for different widths of bars and reduction ratios. Then, the method was applied to analyze cold and hot rollings of rectangular bars and predicted results were compared to those of experiments. Nonuniform distributions of temperature in the bars were predicted by utilizing the temperature equation obtained for a semi-infinite solid under radiation and convection boundary conditions. It was found out that accuracies of spread and roll separating force predictions could be enhanced by using proper values of the T-factor.
흰쥐 후지근 피판에서 허혈-재순환 손상시 pERK1/2 발현에 대한 ${\alpha}-lipoic$ Acid의 효과
송정훈,김민선,박병림,박한수,채정룡,이혜미,나영천,Song, Jeong-Hoon,Kim, Min-Sun,Park, Byung-Rim,Park, Han-Su,Chae, Jeong-Ryong,Lee, Hye-Me,Na, Young-Cheon 대한미세수술학회 2005 Archives of reconstructive microsurgery Vol.14 No.2
Purpose: This study was to evaluate the effect of ${\alpha}-lipoic$ acid, a potent free radical scavenger, on the expression of active form of extracellular signal-regulated kinase (pERK1/2) proteins from hindlimb muscles of rats following ischemia-reperfusion injury. Material and methods: 64 health, $280{\sim}350\;g$ weighted Sprague-Dawley male rats were used. In order to make a muscle flap, the gastrocnemius (GC) and soleus (SOL) muscles were dissected and elevated. The popliteal artery was occluded for 4hours and reperfused for 10 minutes, 30 minutes, 1 hour, 2 hours and 4 hours, respectively. Results: The ischemia by occlusion of the popliteal artery itself caused a minimal change in expression of phosphorylated form of proteins observed in hindlimb muscle. In contrast, after 4 hours of ischemia, immunoreactivity for pERK1/2 in the GC muscle showed dual peaks at 10 minutes and 4 hours after reperfusion. In ${\alpha}-lipoic$ acid treated group, the expression of pERK1/2 was increased significantly compared to I/R-only group. Conclusion: These results suggest that ${\alpha}-lipoic$ acid may protect I/R injury of the skeletal muscle through free radical scavening and activation of intracellular pERK1/2 expression.
송정훈,정의철,권성택,Song, Jeong-Hoon,Jeong, Eui-Cheol,Kwon, Sung-Tack 대한미세수술학회 2009 Archives of reconstructive microsurgery Vol.18 No.2
Purpose: Microsurgery is an essential technique in plastic and reconstructive surgery. However, microsurgical suturing and handling of the instrument are difficult for beginners, and who requires a steep learning curve. Therefore, methods for improving the technical skill are needed. The authors describe the value of a small stereoscopic microscope as a training tool. Materials and Methods: A small stereoscopic microscope was used to help improve the microsurgical skill. Monofilament 10-0 Nylon and a surgical rubber globe were used as a suture material and education material, respectively Result: Stereoscopic view of the operation field was obtained and basic microsurgical suture was possible. Conclusion: The stereoscopic microscope is an effective training tool for beginners of microsurgery with benefits in cost and usefulness in small place.
가시화를 이용한 정적연소기에서 점화장치가 화염전파에 미치는 영향에 관한 연구
송정훈,선우명호,Song, Jeong-Hun 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.12
A visualization study using the schlieren method is adopted in an optically-accessible, cylindrical constant volume combustion chamber to identify the mechanism of ignition energy and ignition system interaction in spark ignited, lean gasoline-air mixture. In order to research the effects of ignition system on flame propagation, two kinds of ignition system are designed, and several kinds of spark plugs are tested and evaluated. To control the discharge energy, the dwell time is varied. The initial flame development is quantified in terms of 2-D images which provides information about the projected flame area and development velocity as a function of ignition system and discharge energy. The results show that high ignition energy and extended spark plug gap can shorten the combustion duration in lean mixtures. The material, diameter and configuration of electrodes the flame development by changing the transfer efficiency from electrical energy to chemical energy and discharge energy. However these factors do not affect of flame development as much a ignition energy or extended gap does.
송정훈,안기정,Song, Jeong-Hun,Ahn, Kee-Jeong Korean Society of Applied Entomology 2013 한국응용곤충학회지 Vol.52 No.4
남한 미기록종인 Blepharhymenus koreanus Pa$\acute{s}$nik (호리바수염반날개) (신칭)과 Tachyusa wei Pace (배구멍바수염반날개)(신칭)을 처음으로 기록한다. 두 종에 대한 성충의 사진, 재기재 및 주요 형질에 대한 그림을 함께 제시한다. Blepharhymenus koreanus Pa$\acute{s}$nik and Tachyusa wei Pace are recorded for the first time in South Korea. Habitus photographs, redescriptions and illustrations of diagnostic characters are provided.