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>

Pulse Shape Discrimination of Nuclear Recoil and Electron Recoil Events With a NaI(Tl) Crystal for Dark Matter Search

Kim, K. W.,Adhikari, G.,Adhikari, P.,Choi, S.,Ha, C.,Hahn, I. S.,Jeon, E. J.,Joo, H. W.,Kang, W. G.,Kim, H. J.,Kim, N. Y.,Kim, S. K.,Kim, Y. D.,Kim, Y. H.,Lee, H. S.,Lee, M. H.,Leonard, D. S.,Oh, S. Y IEEE 2016 IEEE transactions on nuclear science Vol.63 No.2

<P>In order to investigate discrimination between nuclear recoil and electron recoil events for the KIMS-NaI dark matter search experiment, we measured the pulse shapes produced by neutrons and gamma rays in a NaI(Tl) crystal. Relatively good pulse shape discrimination (PSD) power due to high light output of recently developed crystals makes it possible to test whether the annual modulation signal observed by the DAMA/LIBRA experiment is caused by nuclear recoil events. We applied the PSD to underground data taken with a 9.15 kg low-background and high-light-output NaI(Tl) crystal for 134 days. Good agreement between underground data and electron recoil events was observed.</P>

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1996)

김재홍,황동규,전재홍,김윤석,김중환,김용준,이창균,임동진,김현수,조창근,김경문,박상훈,전우형,김희성,이호정,차명수,김갑형,김형석,김석우,황지환,박병순,권오상,이민수,송기훈,성소영,이인섭,부태성 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.2

Background : In recent years, gonorrhea has been panedemic and remains one of the most commom STDs in the world, especially in developing countries. Objective & Methods: For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results: In 1996, 139 strains of N. gonorrhoeae were isolated, among which 53(39.0%) were PPNG. Conclusion: Our results suggests that after a peak of 74.3% in 1993, the prevalence of PPNG in Seoul is gradually declining.

HDPE 폐비닐 개질 아스팔트 혼합물의 강도 및 공용 특성 연구

김광우 ( Kim Kwang Woo ),이기호 ( Lee Gi Ho ),권오선 ( Kwon Oh Sun ),조문진 ( Cho Mun Jin ) 한국농공학회 2004 한국농공학회 학술대회초록집 Vol.2004 No.-

본 연구는 폐비닐 펠렛을 도로포장재료로 재활용하여 자원절약 및 아스팔트 혼합물의 품질향상을 위한 연구이다. 이를 위하여 폐비닐의 첨가량별 배합설계를 수행하여 적정 폐비닐 첨가량과 최적 아스팔트 함량으로 편마암과 화강암 2가지 골재와 폐비닐인 RHDPE의 함량을 4가지로 혼합물을 제작하여 8종류의 개질 혼합물과 2종류의 무개질 혼합물을 제작하였다. 그리고 이 공시체에 대하여 마살안정도, 간접인장강도 및 Kim test와 반복주행시험 등 실내시험을 통하여 혼합물의 특성을 분석하였다. 폐비닐 첨가량은 RHDPE가 8%일 때 안정도와 간접인장강도 모두 가장 우수한 것으로 나타났고 취성도 나타나지 않았다. RHDPE를 첨가한 혼합물에 대하여 Kim test를 수행한 결과 DR과 DS 모두 높은 상관성을 보였다. 그리고 반복주행시험에서는 RHDPE를 첨가한 혼합물이 일반 혼합물보다 우수하였다. 향후 많은 실험을 통해 RHDPE의 우수성을 입증한다면 소성변형 저항성에 우수한 재료로 이용될 수 있을 것이다. This study is a fundamental research for recycled high-density polyethylene (RHDPE) in asphalt mixture for improving roadway pavement. Mix design was conducted by RHDPE content and optimum asphalt content (OAC) was determined for dense-graded surface course mixture. Marshall stability test, indirect tensile strength (ITS) test, wheel tracking test and Kim-test were carried out to measure the characteristics of RHDPE-added asphalt concretes. From the results of this study, RHDPE in asphalt mixture is possible. It could be considered that adding too much RHDPE in asphalt mixture is not proper. The optimum content of RHDPE was appeared to be 8%. In Kim-test, Statistical analysis were performed for each loading head and aggregate to find out correlation between SD values and each rut parameter. The analysis result showed that SD had very high coefficient of determination on the average with rut parameters.

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.

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.

Background study of NaI(Tl) crystals for the KIMS-NaI experiment

Adhikari, P,Adhikari, G,Choi, S,Ha, C,Hahn, I S,Jeon, EJ,Joo, H W,Kang, W G,Kim, H J,Kim, H O,Kim, K W,Kim, N Y,Kim, S K,Kim, Y D,Kim, Y H,Lee, H S,Lee, J H,Lee, M H,Leonard, D S,Li, J,Oh, S Y,Olsen, Institute of Physics Publishing Ltd 2016 Journal of Physics: Conference Series Vol.718 No.-

HDPE 개질 아스팔트 혼합물의 강도 및 변형특성

김광우,이기호,권오선,고태영 강원대학교 부설 석재복합신소재 제품연구센터 2004 석재연 논문집 Vol.9 No.-

본 연구는 폐비닐 펠렛을 도로포장재료로 재활용하여 자원절약 및 아스팔트 혼합물의 품질향상을 위한 연구이다. 이를 위하여 폐비닐의 첨가량별 배합설계를 수행하여 적정 폐비닐 첨가량과 최적 아스팔트 함량으로 편마암과 화강암 2가지 골재와 폐비닐인 RHDPE의 함량을 4가지로 혼합물을 제작하여 8종류의 재질 혼합물과 2종류의 무개질 혼합물을 제작하였다. 그리고 이 공시체에 대하여 마샬안정도, 간접인장강도 및 Kim test와 반복주행시험 등 실내시험을 통하여 혼합물의 특성을 분석하였다. 폐비닐 첨가량은 RHDPE가 8%일 때 안정도와 간접인장강도 모두 가장 우수한 것으로 나타났고 취성도 나타나지 않았다. RHDPE를 첨가한 혼합물에 대하여 Kim test를 수행한 결과 DR과 DS 모두 높은 상관성을 보였다. 그리고 반복주행시험에서는 RHDPE를 첨가한 혼합물이 일반 혼합물보다 우수하였다. 향후 많은 실험을 통해 RHDPE의 우수성을 입증한다면 소성변형 저항성에 우수한 재료로 이용될 수 있을 것이다. This study is a fundamental research for recycled high-density polyethylene (RHDPE) in asphalt mixture for improving roadway pavement. Marshall mix design was conducted and optimum asphalt content(OAC) was determined for dense-graded surface course mixture by RHDPE content. Marshall stability test, indirect tensile strength (ITS) test, wheel tracking trest and Kim-test were carried out to measure the characteristics of RHDPE-added asphalt concretes. From the results of this study, RHDPE in asphalt mixture if possible. It could be considered that adding too much RHDPE in asphalt mixture is not proper. The optimum content of RHDPE was appeared to be 8%. In Kim-test, statistical analysis was performed for each loading head and aggregate to find out correlation between S_(D) values and each rut parameter. The analysis result showed that S_(D) had very high coefficient of determination with rut parameters on the average.

Analysis of the Motion of a Harmonic Oscillator Coupled to Faraday's Law

KIM*, Se-Hun,KO, Tae-Eon,LEE, Se-Hyun,KIM, Kwang-Sun,OH, Seung-Won,KIM, Hyun-Seok Korean Physical Society 2018 새물리 Vol.68 No.1

양궁 선수의 마음챙김 능력 향상을 위한 심리훈련 프로그램 적용

김진호(Kim, Jin-Ho),오원석(Oh, Won-Seok) 한국사회체육학회 2017 한국사회체육학회지 Vol.0 No.67

The purpose of this study is to investigate the effects of mindfulness training with psychological techniques in a professional archery team in South Korea. First of all, it is conducted to find the changes in mindfulness through the KIMS during the mindfulness training, and to analyze the changes in both mindfulness and psychological technique factors. After ten times of meditation (1h-1h30m/1d), ACT and MAC based on the mindfulness training program, there were significant positive influences of psychological factors such as techniques, acceptance, concentration behavior and attention behavior on an intervention group compared to a control group, resulting in KIMS. Although there were no significant differences in confidence and teamwork in the intervention group after the psychological techniques, there were positive effects on willpower, goal setting , concentration, anxiety control and imagery statistically in the intervention group. In conclusion, mindfulness training has positive effects on the mindfulness in Korean archers. This training also has a positive influence on psychological technique factors such as attention, imagery, concentration and anxiety control. According to previous literatures, it is proved that there were positive effects on the psychological technique factors with the changes in mindfulness. Therefore, it is required to develop tools which can measure the mindfulness and to apply the correlation of mindfulness and psychological techniques to the field.