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.

Association of Change in Smoking Status and Subsequent Weight Change with Risk of Nonalcoholic Fatty Liver Disease

Jeong Seogsong,Oh Yun Hwan,Choi Seulggie,Chang Jooyoung,Kim Sung Min,Park Sun Jae,Cho Yoosun,Son Joung Sik,Lee Gyeongsil,Park Sang Min 거트앤리버 소화기연관학회협의회 2023 Gut and Liver Vol.17 No.1

Background/Aims: Smoking is considered a risk factor for the development of nonalcoholic fatty liver disease (NAFLD). However, the association of a weight change after a change in smoking status and the risk of NAFLD remains undetermined. Methods: This study used the Korean National Health Insurance Service-National Sample Cohort. Based on the first (2009 to 2010) and second (2011 to 2012) health examination periods, 139,180 adults aged at least 40 years were divided into nonsmoking, smoking cessation, smoking relapse, and sustained smoking groups. NAFLD was operationally defined using the fatty liver index. The adjusted odds ratio (aOR) and 95% confidence interval (CI) were calculated using multivariable-adjusted logistic regression. Results: Compared to nonsmoking with no body mass index (BMI) change, the risk of NAFLD was significantly increased among subjects with BMI gain and nonsmoking (aOR, 4.07; 95% CI, 3.77 to 4.39), smoking cessation (aOR, 5.52; 95% CI, 4.12 to 7.40), smoking relapse (aOR, 7.51; 95% CI, 4.81 to 11.72), and sustained smoking (aOR, 6.65; 95% CI, 5.33 to 8.29), whereas the risk of NAFLD was reduced among participants with BMI loss in all smoking status groups. In addition, smoking cessation (aOR, 1.76; 95% CI, 1.35 to 2.29) and sustained smoking (aOR, 1.64; 95% CI, 1.39 to 1.94) were associated with higher risk of NAFLD among participants with no BMI change. The liver enzyme levels were higher among participants with smoking cessation and BMI gain. Conclusions: Monitoring and management of weight change after a change in smoking status may be a promising approach to reducing NAFLD.

물-에너지-식량-탄소 넥서스를 이용한 통합물관리 모델 평가 연구 - 영산강 수계를 중심으로 -

나라 ( Na Ra ),박진현 ( Park Jin-hyeon ),주동혁 ( Joo Donghyuk ),김하영 ( Kim Hayoung ),유승환 ( Yoo Seung-hwan ),오창조 ( Oh Chang-jo ),이상현 ( Lee Sang-hyun ),오부영 ( Oh Bu-yeong ),허승오 ( Hur Seung-oh ) 한국농촌계획학회 2023 농촌계획 Vol.29 No.1

Active attention and effort are needed to develop an integrated water management system in response to climate change. In this study, it proposed models for cross-use of agricultural water and river maintenance water using sewage treatment water as an integrated water management system for the Yeongsan River. The impact of the integrated water management models was assessed by applying the concept of Nexus, which is being presented worldwide for sustainable resource management. The target year was set for 2030 and quantitatively analyzed water, energy, land use and carbon emissions and resource availability index by integrated water management models was calculated by applying maximum usable amount by resource. An integrated water management system evaluation model using the Nexus concept developed in this study can play a role that can be viewed in a variety of ways: security and environmental impact assessment of other resources. The results of this research will be used as a foundation for the field of in the establishment of a policy decision support system to evaluate various security policies, as we analyzed changes in other factors according to changes in individual components, taking into account the associations between water, energy, food, and carbon resources. In future studies, additional sub-models need to be built that can be applied flexibly to changes in the future timing of the inter-resource relationship components. 1)

Sphingosine 1-Phosphate and Sphingosine Kinase Activity during Chicken Embryonic Development

Choi, Chang-Hwan,Jeong, Ji-Seon,Yoo, Bo-Im,Jin, You-Xun,Moon, Dong-Cheul,Yoo, Hwan-Soo,Oh, Seik-Wan,Hong, Seon-Pyo,Lee, Yong-Moon 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.4

The chicken embryo has been weil used in studies of the developmental process, and during development sphingosine and sphingosine 1-phosphate (So1P) are considered critical mediators of cell death and survival. In this study, we compared the sphingolipid contents of chicken embryos during the early embryonic development period from day 3 to day 6. HPLC analyses of sphingosine and So1P in chicken embryos revealed that sphingosine levels were greatly reduced on day 4 whereas So1P levels were not significantly changed. Sphingosine kinase(Sphk) activities, which require sphingosine as substrate to produce So1P, were also greatly reduced on day 4. Collectively, we found sphingosine levels and Sphk activities, but not So1P levels are changed in early stage of chicken embryos development.

적층각 변화에 따른 복합재료 회전익의 구조적 연성에 관한 연구

변창환,유용석,오택열 경희대학교 산학협력기술연구원 1997 산학협력기술연구논문집 Vol.3 No.-

This study is made allowance for using one dimensional modeling method that extracts equivalent stiffness matrix used the reduction of degree of freedom in order to sufficiently express the cross section of rotor blade and the material properties of composite. Modern helicopter rotor blade which are made from anisotropic material is very important a subject on the tailoring based on coupling tearms by changing of ply angle. In basing on this, we have searched for coupling terms by changing of ply angle of composite rotor blade and the dynamic behaviour of rotor blade for each coupling term.

Protective Effects of Portulaca oleracea L. Extract against Matrix Metalloproteinase Production and Reactive Oxygen Species Generation Induced by Ultraviolet B Radiation in Human Keratinocytes

Jung Hwan Oh(오정환),Fatih Karadeniz(파티 카라데니즈),Jung Im Lee(이정임),So Young Park(박소영),Youngwan Seo(서영완),Chang-Suk Kong(공창숙) 한국생명과학회 2018 생명과학회지 Vol.28 No.8

쇠비름(Portulaca oleracea.L)은 쇠비름과에 속하는 한해살이풀로서 리놀렌산과 같은 불포화지방산, 페놀성 화합물, 플라보노이드, 비타민 C, 미네랄 함량이 높은 것으로 보고되어 있다. 본 연구에서는 쇠비름 추출물을 이용하여 UVB를 조사한 인간각질형성세포에서 광노화 억제능을 확인하였다. Matrix metalloproteinases는 세포의 기질을 분해하는 효소로 MMP-1는 collagenase, MMP-2와 MMP-9는 gelatinases로 피부 진피층을 구성하는 type Ⅰ collagen을 분해시키는데 영향을 미친다. UVB를 조사한 인간각질형성세포에서 쇠비름 추출물을 처리했을 때 MMP-1, -2, -9의 발현이 감소하였으며, type Ⅰ procollagen의 발현은 증가하는 것으로 나타났다. 또한 쇠비름 추출물을 처리한 군에서 UV에 의한 ROS 생성이 감소하였는데 이는 Nrf-2의 활성화를 통한 항산화 인자 SOD-1과 OH-1의 발현 증가로 인해 세포내 ROS 생성이 감소한 것으로 사료된다. 따라서 본 연구 결과를 통해 쇠비름 추출물이 UVB를 조사한 인간각질형성세포에서 MMP 인자 및 항산화 인자의 발현 조절을 통해 광노화로부터의 세포 보호능을 가지는 것을 확인하였으며 나아가 화장품 소재로서의 개발 가능성을 확인하였다. Portulaca oleracea L. is an edible plant widely consumed in daily diet throughout Europe, Asia and America. In this study, protective effects of P. oleracea L. extracts against oxidative stress and matrix metalloproteinase (MMP) activity induced by ultraviolet B (UVB) radiation were investigated using HaCaT immortal human keratinocytes. In this context, the mRNA and protein productions of MMPs (MMP-1, -2, and -9) and type I procollagen, which are major markers of photoaging induced by UVB radiation in HaCaT keratinocytes, were evaluated. Furthermore, UVB-induced reactive oxygen species (ROS) generation and mRNA and protein expression levels of superoxide dismutase-1 (SOD-1), oxygenase-1 (OH-1), and nuclear factor-erythroid 2-related factor-2 (Nrf-2), all of which are associated with the antioxidant balance, were investigated. As shown by the results, UVB radiation induced ROS formation and led to increased production of MMPs and decreased collagen production in human keratinocytes, which resulted in skin photoaging or photodamage. The treatment with P. oleracea L. extracts downregulated MMP (MMP-1, -2, and -9) production and upregulated type I procollagen expression in UVB-induced HaCaT cells. Furthermore, treatment with the extracts decreased UVB-induced ROS generation and increased the expression of antioxidant enzymes, such as SOD-1 and OH-1, through the Nrf-2 pathway. Taken together, these results suggest that P. oleracea L. extracts could be a potential cosmeceutical agent for the prevention of skin photoaging or photodamage.

이상기후 발생이 가을배추 생산자 및 소비자에게 미치는 영향

조재환 ( Jae Hwan Cho ),서정민 ( Jeong Min Suh ),강점순 ( Jum Soon Kang ),홍창오 ( Chang Oh Hong ),신현무 ( Hyun Moo Shin ),이상규 ( Sang Gyu Lee ),임우택 ( Woo Taik Lim ) 한국환경과학회 2013 한국환경과학회지 Vol.22 No.12

The purpose of this article is analyzing the economic impacts of abnormal climate on fall chinese cabbage farmers and consumers in Korea, with employing the equilibrium displacement model. Our results show that there were little difference in gross farm income, even though there were significant yield reductions due to abnormal climate changes. However periodic occurrences of abnormal climates caused serious damage to consumption levels which had declined by 10.6~17.1 percent with higher prices by 15.3~24.6 percent than normal climate years since 1990.

最近 8年間의 精神神經科 入院 外來 및 患者에 對한 統計的 考察(1960年∼1967年)

李哲奎,盧英一,張煥一,金明源,任允明,韓東洙,吳承煥,金光日 大韓神經精神醫學會 1969 신경정신의학 Vol.8 No.1

1) The number of the out-and in-patients had increased year after year (Table Ⅰ & Ⅲ). 2) Schizophrenia was the greatest number of the in-patients and its rate to whole was 49.1 percent, and neurosis was the greatest number of the out-patients and its rate to whole was 41.66 per cent (Table Ⅰ & Ⅶ). 3) In in-patients, hysteria revealed relatively large in percentage as 11.8% than the other groups (Table Ⅰ). 4) The rate of the male hysteria patients to all male patients was 3.5 per cent and the rate of female hysteria was 20.5 per cent (Table Ⅱ). 5) In in-patients, all the patients of general paresis and alcoholism were only males in sex(Table Ⅱ). 6) In in-patients of schizophrenia, the ratio of the male patients to the female patients was 57.0 : 43.0, but the each rate of each total numbers of the all diseases of the both sexes was almost same (Table Ⅲ). 7) The largest age group of the all patients was between 21∼30 years old, and the next was between 31∼40 years in in-patients (Table Ⅲ). 8) The largest age group of schizophrenia patients was between 21∼30 years and that of M.D.R patients was between 31∼40 years in in-patients (Table Ⅲ). 9) In in-patients of hysteria, the largest age group was between 31∼40 years, and the next was between 21∼30 years (Table Ⅲ). 10) The results of treatment in in-patients were as followings; Recovered; 27.6% Much improved; 43.1% Slightly improved and no changed; 28.2% (Table Ⅳ) 11) The results of treatment in schizophrenia of the in-patients were as followings; Recovered; 19.1% Much improved; 48.3% Slightly improved and no changed; 32.1% (Table Ⅴ) 12) The mode of treatment had been somewhat changed during last 8 years from 1960 to 1967 in treatment of the in-patients (Table Ⅵ). (1) The combined therapy of tranquilizers and EST had been increased, but the therapy of tranquilizer alone or EST alone had been decreased, compared to 1960. (2) The therapy of ICT in the treatment of in-patients had been much decreased.

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.