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>

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.

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

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>

한우에 감염된 Theileria sergenti merozoite의 순수분리와 genomic DNA probe에 관한 연구

채준석,이주묵,권오덕,채건상 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.17 No.-

To make the genomic DNA probe of Theileria sergenti, the merozoites were purified from bovine crythrocytes. The infected erythrocytes were lysed by Aeromonas hydrophila(Ah-1) hemolysin, and the parasites were isolated by ultracentrifugation on a Percoll discontinuous density gradient. For construction of a T sergenti genomic DNA library, T sergenti DNA was digested with PstI and the fragments were ligated into the PstI site of pUC19 before transformation of Escherichia coli JM83. Out of thousands of transformants obtained by transformation of E coli JM83 with the genomic library, three plasmids were chosen. The sizes of the inserted DNAs were 2.9kb(2.4kb and 0.5kb) in pKTS1, 4.3kb in pKTS2 and 1.5kb in pKTS3, respectively. The DNA fragments used as probe KTS1(2.4kb), KTS2(4.3kb) and KTS3(1.5kb) were labeled digoxigenin-11-dUTP for the Southern hybridization. In Southern hybridization, all of the probes(KTS1, KTS2 and KTS3) reacted specifically to T sergenti DNA, but not to bovine leucocyte DNA. In order to find out the sensitivities of the digoxigenin-11-dUTP-labeled KTS1 and KTS3 as the probes, purified merozoite DNA and bovine DNA(control) were checked by dot blot hybridization with the probes. Both of the probes, KTS1 and KTS3, detected as minimum amount of 975pg of the T sergenti DNA, but not bovine DNA even to 500ng.

원격조작에 의한 작업대상물 강성과 마찰 특성의 동정

권혁조,전지명,김진옥,문일동,오재윤 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2002 工學硏究 Vol.33 No.-

This study performs a workpiece stiffness and frictional characteristic identification experiments by teleoperation. Experiments are performed using a bilateral force feedback teleoperation system. It is composed of a master manipulator, the slave manipulator equipped with a force/torque sensor, and a real-time control system. To control the teleoperation system, a position-force controller is developed. The slave manipulator is controlled by the master manipulator's position command and the master manipulator is controlled by the force information from the slave manipulator. This study presents a method to find the slave manipulator's stiffness. And, this study presents a method to compute the workpiece stiffness based on the measured pressing force and deflection at the slave manipulator. Also, this study performs a workpiece frictional characteristic identification experiments. In the experiments, the slave manipulator rubs a workpiece with an arbitrary pressing force. While the slave manipulator rubs a workpiece, a vertical force and a frictional force are measured and the ratio of a frictional force to a vertical force is considered as a frictional characteristic.

ECT (European Compression Technic) System 을 사용한 下顎骨 骨折의 治驗例

金晤煥,申曉根,宋采炫,崔秉河,權泰鎬 全北大學校 齒醫學硏究所 1983 전북치대논문집 Vol.1 No.1

The authors in the Dept. of Oral & Maxillo-facial Surgery.J.N.U Hospital could have the following results after treatment of eight mandibular fractures patients with the E.C.T.(European Compression Technic)System. 1. Accurate reduction of the fractured bone. 2. Minimization of the soft tissue injury during operations. 3. No post-operative intermaxillary fixation was necessary. 4. Good recovery of the occlusion.

자연 동굴 토양 방선균의 속 다양성 분포

임채영,권오성,김판경,박동진,이동희,김창진 한국산업미생물학회 1996 한국미생물·생명공학회지 Vol.24 No.5

국내에 소재 하는 자연 동굴 중 충청북도의 고수굴, 천둥굴, 노동굴, 강원도의 고씨굴, 경상북도의 성류굴, 제주도의 협재굴, 쌍용굴, 만장굴 등 8개 동굴의 내부에 존재하는 토양 방선균 분포를 조사하였다. 그 결과 전체적인 속 수준의 분포로서는 Streptomyces가 52.5%, Micromonospora가 16.3%, Nocardioform 22.8% 정도 분포하고 있었으며 Kineosporia, Actinomadura, Nocardiopsis, Streptosporangium의 순서로 방선균이 0.3~1.4% 정도 분포하고 있었다. 지금까지 보고된 일반적인 방선균 분포와 비교해 볼 때 특히 Streptomyces의 분포 비율이 낮고 상대적으로 Micromonospora, Nocardioform이 많이 분포하고 있었다. 한편 노동굴 지역을 대상으로 동굴 내부와 외부로 나누어 방선균 분포를 비교해 보았다. 그 결과 동굴의 내부에는 Streptomyces가 52.0%, Micromonospora가 16.8%, Nocardia가 32.0% 정도 분포하였고 외부에서는 Streptomyces가 75.8%, Micromonospora가 10.7%, Nocardia가 7.1% 정도 분포하였다. 따라서 동일 지역 내에서도 동굴의 내부와 외부에 따라서 큰 차이를 나타내고 있었다. 그리고 분리된 방선균 중에서 Streptomyces속 균주의 형태적인 특징을 조사한 결과, 기균사의 색에 있어서는 회색 계열 45.7%, 적색 계열 7.8%, 황색 계열 2.3%, 녹색 계열 13.2%, 백색 계열 27.1%, 불량 3.9%의 분포를 나타내었다. 일반적으로 Streptomyces속 방선균에서 잘 분리되는 회색과 적색 계열의 분리 비율은 크게 낮아 졌으나 희소한 녹색과 백색 계열은 분리 비율이 크게 증가하였다. 그리고 성류굴에서는 황색, 녹색, 백색, 계열등 다양한 계열의 Streptomyces속 방선균이 많이 분리되었다. 포자 연쇄의 형태에 있어서는 retinaculiaperti 형태가 35.7%, spirales 형태가 12.4%, rectiflexibiles 형태가 51.9%로 나타났다. Total 276 soil actinomycete strains were isolated from 46 soil samples collected at domestic natural caves; the Kosu, Chundong, and Nodong caves at Chungbook province, the Kossi cave at Kangwon province, the Sungruye cave at Kyungbook province, the Hyupjae, Ssangyoug, and Manjang caves at Cheju province. All of these isolates were identified to the genus level based n morphological and physiological characteristics. As the result, 52.5% of those isolates were Streptomyces, 16.3% were Micromonospora, 22.8% were Nocardioform group, 1.1% were Actinomadura, 0.3% were Nocardiopsis, 0.3% were Streptosporangium, 0.3% were Nocardioides, 1.4% were Kineosporia, 4.7% wee the others. Streptomycete strains were the most abundant, but were relatively less comparing to general distribution pattern. Nocardioform and Micromonospora strains were quite abundant, and other rare actinomycete groups were somewhat abundant comparing to general distribution pattern previously reported. Especially Nocardioform strains were highly abundant at almost of the natural caves.

슬괵건을 이용한 후방 십자 인대 재건술시 횡고정 핀을 이용한 대퇴 터널 고정술

인용,권오수,박원종,공재관 대한슬관절학회 2003 대한슬관절학회지 Vol.15 No.1

목적 : 슬괵건을 이용한 후방 십자 인대 재건술 시행시 대퇴 터널을 횡고정 핀으로 고장하는 술식을 시행하고 그 결과를 보고자 한다. 대상 및 방법 : 2001년 9월부터 2002년 3월까지 동반손상이 없는 grade Ⅲ 이상의 후방 십자 인대 손상으로 네 겹의 슬괵건을 이용한 후방 십자 인대 재건술을 받고 1년이상 추시가 가능하였던 8예를 대상으로 하였다. 전 예에서 대퇴 터널을 횡고정 핀으로 고정하였으며 경골 터널은 Intrafix(Mitek_(?), USA)를 이용하여 고정하였다. 기능 평가는 Lysholm 점수, International Knee Documentation Committee(IKDC) 평가 기준과 KT-2000 관절계를 이용한 최대 도수 부하 검사를 이용하였다. 결과 : Lysholm 점수가 술전 평균 54점에서 술후 1년 추시상 89점으로 향상되었다. IKDC 평가 기준상 정상이 2예, 거의 정상이 5예였으며 비정상이 1예 있었다. KT-2000 관절계를 이용한 최대 도수 부하 검사상 술전 평균 12.2 ㎜에서 3.7 ㎜로 호전되었다. 결론 : 슬괵건을 이용한 후방십자인대 재건술시 횡고정 핀을 이용하는 고정방법은 좋은 술식으로 사료된다. Purpose: The purpose of this study is to introduce new fixation technique for posterior cruciate ligament (PCL) reconstruction using quadruple hamstring tendon autograft. Materials & Materials : From September 2001 to March 2002, eight patients received PCL reconstruction using quadruple hamstring autograft for PCL injury without associated procedures for posterolateral complex injures. All femoral tunnels were fixed with cross pins and all tibial tunnels were fixed with Intrafix(Mitek_(?), USA). Clinical assessments consited of Lysholm knee scores, International Knee Documentation Committee(IKDC) evaluation form and manual maximal side to side difference using KT-2000 arthrometer. Result : The average Lysholm knee score improved from 54 preoperative to 89 postoperatively. At the final IKDC evaluation, 2 cases were graded as normal, 5 nearly normal, 1 abnormal. Mean side to side difference of manual maximum posterior displacement with knee in 70° flexion using the KT-2000 arthrometer was 3.7 ㎜. Conclusion : In PCL reconstruction using quadruple hamstring autograft, cross pins are good fixation method with high strength and stiffness.

[1.1.1.1]Paddlane과 할로겐 화합물과의 반응

李愚鵬,吳東元,黃悳海,權明淑,鄭宰準 慶北大學校 師範大學 科學敎育硏究所 2002 科學敎育硏究誌 Vol.26 No.-

[1.1.1]Paddlane has an inverted structure at two bridge-head carbon atoms. We will describe the reaction of [1.1.1]Paddlane and [1.1.1.1]Paddlane. The reaction of [1.1.1]propellane with singlet methylene affored 1,3-Dimethylene as the major product and [1.1.1.1]paddlane as the minor products were obtained. The reaction of [1.1.1]propellane with triplet methylene was carried out in the similar conditions. The result afforded 1,3-Dimethylenecylopropane as the major product and various side products were also obtained. But no trace of [1.1.1.1]paddlane was detected. After the synthesis of [1.1.1.1]paddlane, continuously [1.1.1.1]paddlane reacts with iodide. The product that I expected for 1,3-diiodo-tricyclo[1.1.1.1]hexane is different. and has unsymmetrical structure.