Combustion characteristics of gaseous inverse O₂/H₂ coaxial jet flames in a single-element model combustor

Kim, Tae Young,Choi, Sun,Kim, Young Hoo,Ahn, Yeong Jong,Kim, Hee Kyung,Kwon, Oh Chae Elsevier 2018 ENERGY Vol.155 No.-

<P><B>Abstract</B></P> <P>To effectively design hydrogen (H<SUB>2</SUB>)/oxygen (O<SUB>2</SUB>) liquid rocket engines through understanding the combustion characteristics of H<SUB>2</SUB>/O<SUB>2</SUB> bipropellants, fundamental studies for the bipropellants in different phases are needed. This study is focused on the combustion characteristics of inverse gaseous O<SUB>2</SUB>/H<SUB>2</SUB> coaxial jet flames in a single-element model combustor as a preliminary step for succeeding studies of injection at different phases in the combustor, visualizing flame structure by direct imaging, OH<SUP>∗</SUP> chemiluminescence and OH planar laser-induced fluorescence. With increasing Reynolds number (Re), the frequency of occurrence of the local flame extinction increases and the length of the disconnected OH reaction zone is extended. The OH layer thickness increases downstream, while it is almost constant where the local flame extinction occurs and decreases with increasing Re due to the enhanced strain and scalar-dissipation rates. The excessive flame wrinkledness increases the local flame strain rate and results in the local flame extinction, exhibiting the tendency of increasing and then decreasing flame surface density with increasing Re. The probability density function of OH intensity quantifies the fluctuation intensity of OH radicals and the possibility of the local flame extinction. A useful database is provided for modeling the combustion of H<SUB>2</SUB>/O<SUB>2</SUB> bipropellants under different phases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A useful database for modeling the H<SUB>2</SUB>/O<SUB>2</SUB> bipropellant combustion is provided. </LI> <LI> Local flame extinction frequently occurs at high Reynolds number (<I>Re</I>). </LI> <LI> OH probability density function indicates the possibility of local extinction. </LI> <LI> Flame surface density increases and then decreases with increasing <I>Re</I>. </LI> <LI> Strong burning of O<SUB>2</SUB>/H<SUB>2</SUB> causes laminar-like combustion near the injector lip. </LI> </UL> </P>

Algal bioassay 에 의한 조류생장 제한영양염류 결정

오희목(Hee Mock Oh),이석준(Seog June Lee),김성빈(Seong Bin Kim),박미경(Mi Kyung Park),윤병대(Byung Dae Yoon),김도한(Do Han Kim) 한국하천호수학회 1998 생태와 환경 Vol.31 No.2

Determination of Limiting Nutrient for Algal Growth by Algal Bioassay. Oh, Hee-Mock, Seog June Lee, Seong-Bin Kim, Mi- Kyung Park, Byung-Dae Yoon and Do-Han Kim (Environmental Microbiology Research Unit, Korea Research Institute of Bioscience and Biotechnology, Taejon 305-333, Korea and Water Resources Research Institute, Korea Water Resources Corporation, Taejon 305-390, Korea) Water quaiity and algal growth potential (AGP) using Microcystis aeruginosa were investigated from April to September 1997 in Daechung Reservoir. Secchi disk transparency was 1.1 m in August. Chlorophyll-a concentrations were higher than 10㎍/l at all samples. Total phosphorus concentration was in a range of 0.020∼0.027mg/l which is at the approximate value of 0.03 mg/l, the general critical level of eutrophication. These results indicate that Daechung Reservoir is in an eutrophic state except some temporary times and restricted sites. Phosphorus uptake rate of M. aeruginosa was higher in the water from the epilimnion than in the hypolimnion and also higher under light condition than under dark condition. Therefore, phosphorus uptake rate appears to depend on cellular phosphorous content and light condition, a meaning of endergonic process. Phosphorus was the most frequently limiting nutrient: phosphorus was limiting algal gowth in April and May, nitrogen, phosphorus and trace elements were the limiting factors for algae in August, and trace elements in September. If a fast growing alga, M, aeruginosa, is used as a test organism for assaying AGP, in vivo fluorescence instead of dry weight can be measured for algal biomass and incubation period can be reduced from traditional 14 days to 7 days.

노인의 영적 간호요구

최미혜,김경희,김귀옥,김기숙,김수강,김정신,김춘숙,노흥진,박지연,성혜연,오명선,이선희,이원옥,이윤영,이현수,장명재,차혜경,채정선,홍상희 중앙대학교 의과대학 간호학과 간호과학연구소 2001 중앙간호논문집 Vol.5 No.1

This study was designed to exam the aged's needs for spiritual nursing care. The purpose was to serve as a basis for the development of spiritual nursing practice. The major findings are as follows : 1. The degree of needs for spiritual nursing care as area was that needs of love and relationship mean 22.0, needs of meaning and object mean 28.2, needs of forgiving mean 13.5. Total needs for spiritual nursing care mean 63.7, which was on the upper middle level. The needs of meaning and object was rated highest. 2. Among the general characteristics of the subjects, needs of love and relatiohship wasn't significanlty different. 3. Among the general characteristics of the subjects, needs of meaning and object was significantly different according to two factors : age(F=7.260, p=0.001), religion(F=5.275, p=0.001). Higher needs of meaning and object was possessed by the older than the younger, by the one who have religion than the other. 4. Among the general characteristics of the subjects, four factors made a significantly difference to needs of forgiving : sex(t=-2.851, p=0.006), age(F=8.201, p=0.001), religion(F=6.928, p=0.000), disease(t=2.327, p=0.024). Higher needs of forgiving was possessed by man than woman, by the older than the younger, by the one who have religion than the other, by the one who have disease than the other.

Properties of inverse nonpremixed pure O₂/CH₄ coflow flames in a model combustor

Choi, Sun,Kim, Tae Young,Kim, Hee Kyung,Koo, Jaye,Kim, Jeong Soo,Kwon, Oh Chae Elsevier 2015 ENERGY Vol.93 No.1

<P><B>Abstract</B></P> <P>In order to evaluate the potential of oxy-combustion of inverse nonpremixed coflow flames using a clean fuel to improve the combustion and emission characteristics compared with the normal coflow flames using air, the fundamental properties of inverse nonpremixed pure oxygen (O<SUB>2</SUB>)/methane (CH<SUB>4</SUB>) coflow flames in a model combustor are experimentally investigated. The combustion stability (extinction) limits, structure and nitrogen oxide (NO<SUB>x</SUB>) emissions of the inverse coflow flames in the quartz-windowed combustion chamber with a single shear coaxial injector and a fully opened exhaust nozzle are measured using OH<SUP>∗</SUP> chemiluminescence, a schlieren imaging system and a gas analyzer. Results show four distinct stability regimes and limits: the attached flame regime, the near-blowout flame regime, blowout limits and blowoff limits. The direct flame and OH<SUP>∗</SUP> chemiluminescence images confirm the cooling effects of chamber walls that cause no steady liftoff flame and only the near-blowout flame. The extinction limits of the inverse CH<SUB>4</SUB>/O<SUB>2</SUB> coflow flames are extended compared with the normal CH<SUB>4</SUB>/air coflow flames and reasonable levels of NO<SUB>x</SUB> emissions are observed, which supports that oxy-combustion of the inverse nonpremixed coflow flames using the clean fuel is acceptable for practical application, providing a useful database for modeling the flames in the confined chamber.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Extended stability limits of inverse nonpremixed O<SUB>2</SUB>/CH<SUB>4</SUB> coflow flames are found. </LI> <LI> Stable, attached flames and oscillating, near-blowout flames are observed. </LI> <LI> Direct flame and OH<SUP>∗</SUP> chemiluminescence images indicate no steady liftoff flame. </LI> <LI> Reasonable levels of NO<SUB>x</SUB> emissions are observed. </LI> <LI> Inverse nonpremixed O<SUB>2</SUB>/CH<SUB>4</SUB> coflow flames are acceptable for practical applications. </LI> </UL> </P>

모델연소실 내 GCH₄/GO₂ 및 GH₂ /GO₂ 동축류 제트화염의 연소특성 기초 연구

최선(Sun Choi),김태영(Tae Young Kim),김희경(Hee Kyung Kim),권오채(Oh Chae Kwon) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12

로켓 엔진의 차세대 액체이원추진제로서 각광을 받고 있는 메탄(CH₄)/산소(O₂) 이원추진제의 기초연소특성 및 연소 안정화의 고유특성 확인을 위해 수소(H2)/산소 이원추진제 연소특성과 비교 연구를 수행하였다. 기초 연소특성 연구를 위한 모델연소실 내에서 기체 메탄(GCH₄)/기체 산소(GO₂) 및 기체수소(GH₂)/GO₂의 동축류 제트화염의 연소안정한계와 직접 사진, OH<SUP>*</SUP> 자발광 이미지를 측정한 결과, GCH₄/GO₂와 GH₂/GO₂ 모두 산소-연료 모멘텀비((O/F)mom)가 감소함에 따라 연소안정한계는 확장되는 경향을 보였으나 GH₂/GO₂ 화염에 비해 GCH₄/GO₂ 화염은 좁은 연소안정한계가 측정되었고, 또한 GCH₄/GO₂ 화염은 이론당량비 조건에서, GH2/GO₂ 화염은 연료과농 조건에서 최대 OH* 강도가 측정됨을 OH<SUP>*</SUP> 자발광 가시화를 통해 확인하였다. Liquid methane (CH₄)/oxygen (O₂) bipropellants have been recently considered as a next-generation propellant due to eco-friendly and non-toxic properties, low cost and high performance. To investigate the unique features of CH₄/O₂ bipropellants, the fundamental combustion characteristics of gaseous CH₄/O₂ and H₂/O₂ coaxial jet flames in a model combustor are investigated through measuring the combustion stability limits and visualizing flames. Results show that the combustion stability limits of GCH₄/GO₂ flames are reduced compared with the GH₂/GO₂ flames. The maximum OH<SUP>*</SUP> intensity of GCH₄/GO₂ flames is observed at near-stoichiometric condition, while the GH₂/GO₂ flames at fuel-rich condition.

비장경색이 동반된 쯔쯔가무시병 1예

오종찬,이범주,장재현,원경준,박경희,김동민,박치영,정춘해 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.1

Tsutsugamushi disease is an acute febrile illness caused by Orientie. tsutsugsmushi. It is characterized by fever, myalgia, lymphadenopathy, and rash. And it can be easily diagnosed by characteristic eschar and serologic testing. Nearly all of the patients with tsutsugamushi disease improve with antibiotics such as doxycycline. However, the fatality rate of untreated cases is seven to ten percent. Splenic infarction is not common disease which is caused by occlusion of the main splenic artery or any of its branches. It is mainly caused by emboli that arise from cardiovascular disease, but sometimes by regional thrombosis associated with leukemia, myeloproliferative disorder, sickle cell anemia, pancreatitis, splenic torsion and septicemia. We experienced one case of tsutsugamushi disease with splenic infarction, which was improved after doxycycline treatment finished.

솔잎 첨가김치의 숙성중 당, 산 및 아미노산의 함량 변화

오영애,김순동,김경희 대구효성가톨릭대학교 식품과학연구소 1997 식품과학지 Vol.9 No.-

솔잎 물추출물(WEPN)을 첨가한 김치의 숙성중 유리당과 유기산 및 유리아미노산의 함량변화를 조사하였다. 미생물의 주 영양원인 유리당은 glucose, fructose, sucrose, mannitol이 검출되었으며, 숙성의 진행에 따라 mannitol은 증가하였으나 glucose, fructose 및 sucrose의 함량은 감소하였다. WEPN 첨가김치에서는 sucrose의 감소율은 무첨가에서 높았으나 glucose와 fructose의 감소율은 첨가김치에서 높았고 mannitol의 증가율은 무첨가 김치에서 높았다. 유기산으로는 oxalic, citric, acetic, malic, succinic, lactic acid가 검출되었다. Oxalic acid, citric acid 및 malic acid는 숙성과 함께 감소하였고 감소율은 무첨가 김치에서 높았다. Acetic acid, succinic acid 및 lactic acid는 숙성중에 증가하였으며, succinic acid는 무첨가 김치에서, malic acid는 첨가김치에서 높은 함량을 보였다. 유리아미노산 함량은 첨가, 무첨가 다같이 숙서이 따라 증가하였는데 WEPN 첨가김치에서 증가율이 높았다. 이러한 현상은 무첨가 김치에서 소모율이 적음에 따른 영향이라 판단되었다. This study was conducted to investigate the effect of pine needle water extract(WEPN) on the shelf-life of kimchi. The extract was added 2% as pine needle basis in kimchi. The contents of free sugar, free amino acid and organic acid, and pH, acidity were determined during fermentation at 10℃. The edible periods of WEPN added kimchi was enhanced to 7days than control kimchi by estimating of pH and acidity. Free sugars, such as glucose, fructose, sucrose and mannitol in kimchi juice were detected. Mannitol was increased but glucose, fructose and sucrose were decreased. The rate of increase in sucrose contents and that of decrease in mannitol contents showed higher at control kimchi than at WEPN added products. The rate of decrease in glucose and fructose contents showed higher at WEPN added kimchi than at control porducts. Free amino acid contents of control kimchi at 0 day and 21th day fermentation were 319㎎ and 551㎎/100g of kimchi, respectively. Its content were also higher in WEPN added kimchi than in that of control during entire fermentation periods. Oxalic, citric, acetic, malic, succinic, lactic acid as kimchi organic acids were detected. The changes in organic acids content of control and WEPN added kimchi showed simillar tendency during fermentation.

골수강내 금속정을 이용한 경골 근위간부 골절의 치료 : AO 골절형과 Poller 나사 사용 유무에 따른 분석 Analysis According to AO Classification and the Poller Screw

오창욱,김성중,전인호,경희수,박병철,인주철,김경훈,우연기 대한골절학회 2004 대한골절학회지 Vol.17 No.2

Flavobacterium odoratum의 TOL 플라스미드를 전달받은 광합성세균으로부터의 수소 생성

오순옥,조인선,이희경,민경희 숙명여자대학교 자연과학연구소 1991 자연과학논문집 Vol.- No.3

Flavobacterium odoratum SUB53의 TOL 플라스미드의 크기는 83 Md 이었으며 TOL 플라스미드에 의한 m-toluate의 최고분해농도는 5 mM이었다. Rhodopseudomonas sphaeroides KCTC1425의 수소생성은 nitrogenase의 활성과 비례하였으며 30 mM malate acid와 질소원으로서 7mM glutamate의 최적농도에서 최고의 수소생성을 보여 주었다. 한편, 0.3mM NH ion에 의해 nitrogenase의 활성이 저해되어 수소 생성이 현저히 감소하였다. F. odoratum SUB53과 Pseudomonas putida mt-2의 TOL 플라스미드는 R. sphaeroides에로의 접합시 수용세포의 대수증식기에서 10시간-15시간 동안에 최적이었으며 helper plasmid pRK2013에 의해 접합능이 증가하였다. Transconjugants인 R. sphaeroides C1(TOL SUB53)과 C2 (TOL mt-2)의 catechol-1,2-oxygenase(C-1,2-O)와 catechol-2,3-oxygenase(C-2,3-O)의 활성을 비교 검토한 결과 C-2,3-O 유전자를 code하는 유전인자는 TOL 플라스미드 위에 있으며, C-1,2-O 유전자의 위치는 chromosome 위에 있는 것으로 사료된다. 전자 공여체로서, m-Toluate는 R. sphaeroides C1과 C2의 TOL 플라스미드에 의하여 분해되어 수소를 생성함을 알 수 있었다. 이 결과는 TOL플라스미드에 의하여 m-toluate가 일차적으로 분해되고 생성된 이차산물로 부터 광선하에서 수소를 생성하는 것으로 추정된다. TOL plsmid size of Flavobacterium odoratum SUB53 was estimated as 83 Md and the optimum concentration of m-toluate degradation by TOL plasmid was 5 mM. H₂ production by Rhodopseudomonas sphaeroides KCTC1425 was largely dependent on nitrogenase activity and showed the highest at 30 mM malate with 7mM glutamate as nitrogen source. Nitrogenase activities were inhibited by 0.3mM NH ions, to be appeared the decrease of H₂ production. Conjugation of TOL plasmids from F. odoratum SUB53 and Pseudomonas putida mt-2 to R. sphaeroides showed the optimum at the exponential stage of recipient cells in presence of helper plasmid pRK2013. According to the investigation of catechol-1,2-oxygenase(C-1,2-O) and catechol-2,3-oxygenase (C-2,3-O) activities of R. sphaeroides C1 (TOL SUB53) and C2 (TOL mt-2), the gene for C-2,3-O is located on TOL plasmid and gene for C-1,2-O on the chromosome of R. sphaeroides. m-Toluate was biodegraded by TOL plasmid in R. sphaeroides C1 and C2, presumably to be produced H₂ gas from the secondary metabolites of m-toluate.

소흑산도 주변해역의 계절별 난류수의 분포

오경희,방익찬,노홍길 제주대학교 해양연구소 1998 해양자원연구소연구보고 Vol.22 No.-