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.

정적 연소기내 혼합기 농도변화에 따른 OH분포 측정

최동석(D.S.Choi),김덕줄(D.J.Kim),오승묵(S.M.Oh),황의상(E.S.Hwang),정용일(Y.I.Jeong) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.6_2

The OH molecule is a highly reactive combustion intermediate and relatively abundant in combustion systems. It also has the availability of convenient UV -laser systems to excite the A²Σ-X²?? electronic transition. The spectroscopic parameters describing this transition are well known. In this research, the OH molecule was measured in the laminar flame burner and constant volume combustion chamber(CVCC) in order to use it as the fundamental data for studying combustion phenomena. The LIF images of the OH molecule in the laminar 리ame burner were caught by using KrF excimer laser and ICCD camera. The natural fluorescence<br/> of OH was also measured by the interference filter(310 nm) and spectrometer in the CVCC at different equivalence ratios.

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.

Hepatic Cirrhosis Occurring in a Young Woodchuck(Marmota monax) Due to Vertical Transmission of Woodchuck Hepatitis Virus(WHV)

Kyu-shik Jeong,정원일,Jae-yong Chung,Mi-young An,Chae-yong Jung,Gyoung-jae Lee,Jong-soo Kang,Byeong-cheol Kang,Young-heun Jee,Bruce H Williams,Young-oh Kwon,Da-hee Jeong 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

Cirrhosis Occurring in a Young Woodchuck (Marmota monax) Due to Vertical Transmission of Woodchuck Hepatitis Virus (WHV)Da-hee Jeong, Won-il Jeong, Jae-yong Chung, Mi-young An, Chae-yong Jung, Gyoung-jae Lee1, Jong-soo Kang1, Byeong-cheol Kang2, Young-heun Jee3, Bruce H Williams4, Young-oh Kwon5 and Kyu-shik Jeong*College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Korea1Shinwon Scientific Co., LTD, Research Institute, Suwon, Korea2Clinical Research Institute, Seoul National University, Seoul 110-744, Korea3College of Veterinary Medicine, Jeju National University, Jeju 690-756, Korea

포스트모던 관광의 지속가능성에 관한 연구

오정준(Oh, Jeong-Joon),이후석(Lee, Hoo-Suk) 한국관광연구학회 2003 관광연구저널 Vol.17 No.1

Postmodern tourism has been conceived as environmentally-friendly tourism and thus sustainable tourism. In reality, however, postmodern tourism tends to have a negative impact on the environment and lives of indigenous people. The purpose of this study is to analyze sustainability of so-called postmodern tourism and to suggest a new direction for postmodern tourism through a case study of Ahbu Oh-Rum in Jeju Island. The case study suggests that economic benefits to and social-cultural impacts on the indigenous people of the development of postmodern tourism in Ahbu oh-rum is very few, while environmental destruction has been increased. For instance, soil erosion resulted from trampling is found in many slopes, and a number of cows are infertile due to tourists' interference. As a result, indigenous p대ple, especially who work at a meadow, prohibit tourists from visiting their meadow because of tourists' negative impact on cows. The case study also finds that Ahbu Oh-Rum destination lucks or destination management systems to conserve the environment of the destination and basic facilities such as tourist roads, visitors centers, and interpretation services for tourists. Therefore, the destination management systems and the basic facilities are necessary to improve the sustainability of postmodern tow-ism in terms of economic revenue and conservation of the environment.

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.

측백나무(Thuja orientalic) 추출물의 산화적 스트레스에 대한 보호효과

오수정ㆍ모정희(Su Jeong OhㆍJeong Hee Mo) 한국인체미용예술학회 2016 한국인체미용예술학회지 Vol.17 No.1

This paper aimed to verify the protective effects of Thuja orientalic extract against oxidative stress caused by H2O2 Rotenone and Paraquat in the keratinocyte(HaCaT cell) of human-derived normal skin for the development of safer health food or functional cosmetic materials. It has been reported that Thuja orientalic has antioxidant effects. In accordance with the cytotoxicity of Thuja orientalic extract against HaCaT cells using MTT, the appropriate concentration was less than 50㎍/mL. Thuja orientalic extract exhibited protective effects against H2O2, rotenone, and paraquat by 86.6%, 86.45%, and 60.24%, respectively, at the concentration of 50㎍/mL. Thuja orientalic extract has protective effects against all three artificial stresses, and more protective effects against H2O2 and rotenone. The analysis results indicated that Thuja orientalic extract had antioxidant effects that could offer protection to the cells from a variety of oxidative stresses. Accordingly, Thuja orientalic extract has a highly applicable value as a functional health food or cosmetic ingredient in the current times in which wellbeing is a priority.

인스트루먼트 패널용 수용성 질감 도료의 물리적 성질

김억(Ok Kim),오우정(Woo-Jeong Oh),전용(Yong Chun),김영태(Young-Tae Kim),안재범(Jae-Beom Ahn),조영호(Youngho Cho) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_3

Physical properties of waterborne soft feel coatings for instrument panel were investigated. Soft feel coatings give warm and velvet touch for cold and hard plastic materials. Waterborne soft feel coating is composed with two parts. Part A contains polyester polyurethane dispersion (PE-PUD), OH-functional water dispersible polyurethane resin (PC-PUD) and OH-functional water dispersible alkyd resin (OH-PA). Part B contains hydrophilic hexamethylene diisocyanate trimer (HHDI). Soft feeling of coated panel was related with the amounts of PC-PUD and OH-PA. The physical properties of coated panel could be controlled by the NCO/OH ratio from Part A and Part B. Soft feeling was enhanced with relevant to PE-PUD content but the content of PE-PUD was limited because of weakening of coated film strength. For excellent touch and good property, the optimum composition of soft feel coat was PC-PUD(30%) and PE-PUD(20%). The results from all reliability tests satisfied soft feeling, scratch, chemical resistance and fogging.

Laminar Lifted Methane Jet Flames in Co-flow Air

Narayan P. Sapkal,Won June Lee,Jeong Park,Byeong Jun Lee,Oh Boong Kwon 한국연소학회 2015 KOSCOSYMPOSIUM논문집 Vol.2015 No.12

The Laminar lifted methane jet flames diluted with helium and nitrogen in co-flow air have been investigated experimentally. The chemiluminescence intensities of OH* and CH₂O* radicals and the radius of curvature for tri-brachial flame were measured using an intensified charge coupled device (ICCD) camera, monochromator and digital video camera. The product of OH* and CH₂O* is used as a excellent proxy of heat release rate. These methane jet flames could be lifted in buoyancy and jet dominated regimes despite the Schmidt number less than unity. Lifted flames were stabilized due to buoyancy induced convection in buoyancy-dominated regime. It was confirmed that increased OH* and CH₂O* concentration caused an increase of edge flame speed via enhanced chemical reaction in buoyancy dominated regime. In jet momentum dominated regime lifted flames were observed even for nozzle exit velocities much higher than stoichiometric laminar flame speed. An increase in radius of curvature in addition to the increased OH* and CH₂O* concentration stabilizes such lifted flames.

알칼리 처리에 의한 폴리에스테르 필름의 강도 및 염색성의 변화

오정숙,이광주,전정희 효성여자대학교 가정대학 학도호국단 1985 家政大論集 Vol.4 No.-

When polester fibers are hydrolyxed in alkaline solution, they dissolve successively from their surface and change their dyeability. We examined the weight loss ofpolyester films treated with NaOH solution under various conditions and the equilibrium.amount of disperse dyes absorbed in films. An uptake of dyes on films treated withan alkaline solution has beer discussed in relat'on to the changes of weight loss of films. The changes of weight loss increased linearly on hydrolyzing time because ofdissolving uniformly froml their surface of films. However. in high concentrations ofalkaline solution, the changes of weight loss increased drastically owing to OH-attackedto the inner regions of films. The tensile strength of hydrolysed films decreased a sodden drop when the weightloss were low. But it decreased gently when weight loss were high. The dye uptake of hydrolyzed films increased a very small amount below 20% ofweight loss. However, it increased remarkably above 20% of weight loss.