메탄/공기 층류 부분예혼합화염의 상세 라디칼(OH*, CH* 그리고 C₂*) 정보와 배기매출물에 관한 실험적 연구

정용기,오정석,전충환,장영준,Jeong Yong Ki,Oh Jeong Seog,Jeon Chung Hwan,Chang Young June 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.2

An experimental study was performed to investigate the effects of partially premixing, varying the equivalence ratios from $0.79{\sim}{\infty}$, on NOx emissions and chemiluminescence of excited $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ radicals in laminar partially premixed flames. the signal from the electronically excited state of $OH^{\ast},\;CH^{ast}\;C_2^{\ast}$ was detected through a band pass filter with a photo multiplier tube, which are processed to the intensity ratio ($C_2^{\ast}/CH^{\ast},\;C_2^{\ast}/OH^{\ast},\;and\;CH^{\ast}/OH^{\ast}$) to reveal the correlation with local equivalence ratio. And measurements of NOx emission were made to investigate the relationship between visible flame appearance, chemiluminescence, and EINOX. The results demonstrated that (1) the flames at ${\phi}<1.59$ exhibited classical double flame structure, at ${\phi}>4.76$, the flames exhibited diffusion flame structure, and the intermediate flames at $1.59<{\phi}<4.76$ was a merged flame, (2) the $OH^{\ast}$ peak was located inside the $CH^{\ast}\;and\;C_2^{\ast}$ radical for all measured conditions and the emission intensity ratio of $C_2^{\ast}/CH^{\ast}\;and\;C_2^{\ast}/OH^{\ast}$ were identified as good marker for local equivalence ratio over a range of ${\phi}=0.79{\sim}1.2\;and\;CH^{\ast}/OH^{\ast}\;is\;0.79<{\phi}<1.9$. However, it was difficult to predict the equivalence ratio in partially premixed flames using this system for ${\phi}>2.38$, (3) the minimum NOX emission index (EINOx) is obtained for a equivalence ratio of 3.19 in the intermediate flames.

이중동축 메탄/공기 층류 부분 예혼합화염에서의 화염구조와 자발광 배출 특성 안쪽관 연료주입의 영향

오정석(Jeong Seog Oh),정용기(Yong Ki Jeong),전충환(Chung Hwan Jeon),장영준(Young June Chang) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11

In this study, the effect of central fuel injection on a coaxial laminar CH₄/air flame was experimented at the defined premixing condition(φ=1.90, σ=50/75/100%, x/D=10). The partial premixing parameter are the equivalence ratio that total fuel is fixed at 200cc/min, the fuel split degree which means the percentage of fuel entering the outer tube to the total amount, and the mixing distance indicating the nonreactant mixture's homogeneity between inner tube top and burner exit. The object is to investigate the flame structure and chemiluminescence characteristics of laminar partial premixed flame as changing mixing parameters. The radical signal was acquired from ICCD camera and PMT. Each intensity was compared with Abel inverted value for measuring the effect of background light on the peak signal location and the intensity at central preheat zone. The results show that the peak location of each radical was broaden as the fuel split degree increasing because the mixing quality was enhanced. and OH* is a good indicator for flame front between reaction and preheat zone. At last C₂* has the same tendency with CH* but a thinner reaction zone than CH* due to a rapid decay on the burned gas side.

메탄 공기 층류 부분 예혼합화염에서 예혼합 정도에 따른 화염구조와 질소산화물의 배출에 미치는 영향에 관한 연구

오정석(Jeong Seog Oh),정용기(Yong Ki Jeong),전층환(Chung Hwan Jeon),장영준(Young June Chang) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11

It is shown that the effect of variable parameters on flame structures and NOx emissions in the laminar<br/> partially premixed methane-air flames with a co-axial Bunsen burner. Objectives of this paper is to<br/> understand the effects of flow variables on NOx emissions and the flame structure with OH<br/> chemiluminescence, including reconstructed image by abel inversion processing at each conditions. A fuel<br/> flowrate of 200 [cc/min] was fixed and the amount of air was varied from 400 to 1200 [cc/min]. The<br/> experimental variables were equivalence ratio( ), fuel split percentage( ) and inner tube recess(x/D). Flow<br/> conditions were ranged from 1.36~4.76(equivalence ratio), 50~100(fuel split percentage) and 0~20(inner<br/> tube recess). NOx analyzer and ICCD camera with a OH filter were used as a main experimental<br/> apparatus. In addition, Abel inversion, which is a kind of tomography and valuable to estimate a<br/> two-dimensional structure of co-axial flames from cubical information, was employed for combustion<br/> diagnostics. Results from this study indicate that the main effects depend on equivalence ratio and next<br/> sigma, x/D for NOx production and OH formation. Throughout Abel inversion, we could affirm the<br/> maximum position and the tendency of OH radical intensity by variants at five axial heights above the<br/> burner exit.

양극성 반고관절 성형술을 이용한 대퇴 경부 골절의 치료

오정환,조병주,안의환 건국대학교 의과학연구소 1998 건국의과학학술지 Vol.8 No.-

Problems of nonunion, avascular necrosis of the femoral head, and loss of fixation are frequently encountered in the management of femoral neck fractures and high complication rates after closed or open reduction and internal fixation technique were reported due to poor bone quality or lack of cooperation in elderly patients. So, another option of hemiarthroplasty for the management of the femoral neck fractures were recommended, especially in elderly patients. We reviewed 20 bipolar hemiarthroplasties which had been performed from April, 1990 to March, 1996 for the femoral neck fractures and followed up for a minimum of 1 year and are reporting their results.

外食産業 特殊性에 대한 考察

吳政煥 경기대학교 호텔경영연구소 1994 호텔경영연구논총 Vol.- No.3

In the rationalization of restaurant management, it is important that manager of the restaurant should consider social attributes. That is, the managers are required to observe modern food service industry in the direction that producer and consumer can be considerated. The public will memorize and envy forever the dinning-out business of J.W. Marriott, Mcdonald of R. Kroc, Lotteria in Korea today. This means that the food service industry which must be operated rationally has been successful. A small and medium restaurant is the business that satisfies basic wants of the public. A large restaurant can be said to be a consumption businessis. But in the case of exporing Know-how and service, the business increases the acquisition of foreign exchange as well as foreigner's purchasing power which makes a great contribution to the improvement of international payments. To this end, managers are asked to operates the food service industry rationally. Accordingly, more government support will be needed, and the actives and affirmative attitudes of managers are also required. Finally, the purpose of this study is to suggest that the managers of restaurants should consider the characteristics of the food service industry so that they may make a great contribution to the successful development of restaurants as a whole.

DNA Conformation Probe로서의 Anionic Potential Reporter 분자의 구조 연구 : Ⅰ. Nalidixic Acid의 공간군 결정 Ⅰ. The Space Group Determination of Nalidixic Acid

오인근,고동성,이천배,서정인,서일환 충남대학교 자연과학연구소 1986 忠南科學硏究誌 Vol.13 No.1

The space group of nalidixic acid(1-ethyl-1, 4-dihydro-7-methyl-4-oxo-1, 8-naphthyridine-3-carboxylic acid, C_12H_12N_2O_3), a clinically important antibiotics, has been determined by single crystal X-ray photographic data collected three-dimensionally using Weissenberg method with Cu Kα radiation (λ=1.5418 Å), as the structural data is required and important for the elucidation of the molecular mechanism of the inhibitory action of the antibiotics on DNA synthesis. The space group is P2_1/c with four molecules in the unit cell of dimensions, a=8.98±0.15, b=13.30±0.03, c=9.50±0.16Å, and β=99.5±0.1°.

배드민턴 드롭샷 동작의 운동학적 분석

오정환,최수남,정익수 한국운동역학회 2005 한국운동역학회지 Vol.15 No.1

C. H. OH, S. N. CHOI, I. S. JEONG. Kinematic Analysis of the Badminton Drop-shot Motion. Korean Journal of Sport Biomechartics, Vol. 15, No. 1, pp. 221-235, 2005. The purpose of this study was to analyse badminton players' drop-shots, in order to make players understand the principles of drop-shot motion in badminton. Three dimensional analysis was used to measure movements such as the time required per section, the change of center of gravity, joint angle and speed, and joint speed. The results of this study revealed as follows: (1) top players are faster than amateurs in the total time required per section; (2) top players moved more in the x-axis and z-axis, while amateurs moved more in the y-axis; (3) the inclination of amateurs was greater than that of top players in all phases; (4) amateurs showed larger angle on the shoulder joints than top players in the first phase, while top players showed larger angle on the shoulder joint than amateurs in the second and third phase. Amateurs' angle was larger on angle joint in the first phase than top players' ones, while top players' angle was larger in the third phase than amateurs; (5) the speed of racket head of top players was faster than that of amateurs; and the velocity of the center of gravity of amateurs was greater than that of the top players. The findings of this study were that gravity decreases during impact and then the velocity increases to perform the follow-through and making the swing fast by increasing the speed of the racket head is most important.

기관골 신생증 1예

오영상,이은우,정종혁,문승원,김수현,김동한,양혁승,박정환,박경옥,강성수,이영직 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

Tracheobronchopathia osteoplastica is a rare disorder of unknown cause characterized by the projection of numerous bony or cartilaginous submucosal nodules into the tracheobronchial lumen with sparing of the posterior membranous portion of tracheobronchial tree. In the past, most of the cases were diagnosed as secondary finding at autopsy. Nowaday, the key component of the evaluation is flexible fiberoptic laryngoscopy and bronchoscopy, which typically demonstrates irregular spicules of subrnucosal bone and cartilage projecting into the tracheobronchial lumen and causing various degrees of airway obstruction. A 45 years old man was visited Sunchon St. Carollo hospital due to discomfort on throat. We saw several nodules just below vocal cord via laryngoscope. The computed tomography revealed multiple small calcified nqdules on trachea and both main bronchi. Pathologic finding of bronchoscopic biopsy showed abnormal proliferation of bony and cartilagious nodules in the tracheal submucosa. These fingdings were consistent with tracheobronchopathia osteoplastica. We report here on a case of tracheobronchopathia osteoplastica with review of literature.

이종마찰압접재 계면의 기계·금속조직학적 거동 및 파면특성 : STS304와 SM15C재를 중심으로 For STS304 and SM15C

오환섭,박경식,박준건,오정국,백영남 慶熙大學校 材料科學技術硏究所 1998 材料科學技術硏究論集 Vol.11 No.-

In this study is behavior of crack propagation and fracture under static tensile load, shear load, rotary bending fatigue load in friction welded dissimilar materials. Crack was observed in fine ferrite zone of SM15C and heat affected zone of STS304. Plastic flow was occured by friction welding process, so direction of crack is inclined with welded surface. Fatigue fracture most occurred in SM15C heat affected zone around interface. Fibrous zone with the view of macroscope and dimple pattern with the view of microscope were observed at fracture surface. Result is more metal micrstructure dependence than stress dependence by mechanical and metallic mechanics.

이종마찰압접재의 변형 및 균열 성장 거동 : STS304 와 SM15C재를 중심으로 For STS304 and SM15C

오정국,오환섭,박준건 조선대학교 동력자원연구소 1997 動力資源硏究所誌 Vol.19 No.1

In this study, behavior of crack growth and fracture under static tensile load in friction welded dissimilar materials, and necking phenomenon occuring at tensile yeilding point is shown. Crack is observed in heat affected zone including fine ferrite region of SM15C and heat affected zone of STS304. Plastic flow was occured by friction welding process, so direction of crack is inclined with welded surface. Fracture behavior of similar material is subject to joint of void, but dissimilar material is liable to joint of micro crack. Fibrous zone with the view of macroscope and dimple pattern with the view of microscope is observed at fracture surface.