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>

최근 10년간 원광의대병원에서 시행한 소아 심장혈관 수술의 임상적 고찰

윤향석,정수미,최두영,오광수,오연균,김종덕,양현웅,이삼윤,김형곤,최종범,최순호,노병석 圓光大學校 醫科學硏究所 1995 圓光醫科學 Vol.11 No.2

We reviewed 10 years experiences of the clinical aspects and early postoperative results in 544 pediatric patients(age less than 16 years old). Among them. 529 cases had the congenital heart diseases, and 15 had the acquired diseases. Open heart surgery was performed in 413 patients. 115 cases were treated with non-open heart surgery. 16 with interventional catheterization. Annual increase of the cardiac patients was not significant in recent 10 years, except slight increase in 1994. The mean age of the study patients had been evidently changed to younger year by year. Total mortality rate of the open heart surgery was 6.4%. The cyanotic congenital heart diseases were high in early postoperative mortality by 25.7%, whereas 4% in acyanotic group. The age group less than one month was most highest in surgical mortality(66.7%). There were no deaths in patients with patent ductus arteriosus(103 cases), atrial septal defect(83 cases) or pulmonary stenosis(17 cases). Among 220 patients with ventricular septal defects(VSD). 10(4.5%) were died early postoperatively. In cyanotic group, the patients with pulmonary atresia with ventricular septal defects(PAVSD), transposition of the great arteries(TGA), interrupted aortic arch(IAA), complex cardiac anomalies with isomerism seemed to be most susceptible to an early death.

골다공증 위험군의 조기발견을 위한 골교체율 지표의 유용성

최종태,오석,한기옥,한인권 대한골대사학회 1996 대한골대사학회지 Vol.3 No.1

골반 자세 변화에 따른 일어서기의 기능적 연결분석의 접근

최종덕,권오윤,이충휘,김종만,김진경 한국전문물리치료학회 2003 한국전문물리치료학회지 Vol.10 No.2

The purpose of this study was to analyze the effects of three different pelvic tilts on a sit-to-stand (STS) and to suggest a new assessment approach based on biomechanical analysis. The three difrent pelvic tilts were: (1) comfortable pelvic tilt sit-to-stand (CPT STS), (2) posterior pelvic tilt sit-to-stand (PPT STS) and (3) anterior pelvic tilt sit-to-stand (APT STS). To determine the onset time of muscle contraction surface electrodes were applied to the rectus femoris muscle (RF), vastus lateralis muscle (VL), biceps femoris muscle (BF), tibialis anterior muscle (TA), gastrocnemius muscle (GCM), and soleus muscle (SOL). The ICC was used for functional linkage analysis. The findings of this study were as follows. First, significant differences were found in kinematic variables and in muscle activation pattern among the three activities. Second, the results of functional integrated analysis revealed that recruited muscle activation patterns changed when the thigh-off was viewed as a reference point. Third, there were independent functional units between the thigh-off and the VL and between the thigh-off and the RF in the functional linkage analysis. The VL and RF acted as prime mover muscles, and more postural adjustment muscle recruitment was required as the demand of postural muscle control increased (PPT STS, APT STS, and CPT STS in order). In conclusion, the findings of this study suggest the following evaluative and therapeutic approach for STS activity. APT STS can be introduced for movement efficiency and functional advantage when abnormal STS is treated. However, excessive APT would change the muscle activation patterns of BF and SOL and require additional postural muscle control to cause abnormal control patterns.

자연형 하천공법 적용 후의 오산천 상류구간의 수질변화 조사

최이송,박재영,윤세철,오종민 慶熙大學校 地球環境硏究所 2002 지구환경논문집 Vol.13 No.-

Recently, Korea is concentrating his concern to restoration of stream because its water quality has been deteriorated by various pollutants generated through urbanization and industrialization. As a test section, upstream section(3.1㎞) of Osan Stream which has the characteristics of the typical small urban stream was restored with natural form by various construction methods. This study was performed to understand the variation of water quality for the section after restored to natural form and to estimate improvement effectiveness of water quality by it through comparison of water quality before and after constructed. Based on the results, it was estimated that, even though inflow of tributaries, water quality was improved at the section of OS1 and OS3 and this was influenced by self-purification increased. Through the comparison with the datum of 1996, we could know that water quality after construction was greatly improved. Therefore naturalization form of Osan Stream contributed to purification of water quality and to restore stream with natural form was estimated as a desirable method for improvement of stream water quality.

중추에서 Prostaglandin계가 Renin-angiotensin System에 미치는 영향

최영태,김종승,문성호,오형균,김재훈,전제열,염철호,윤평진 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.1

Role of prostaglandins on the renin-angiotensin system in the central nervous system was examined in normotensive and 2-kidney, 1 clip (2K1C) hypertensive rats. The experiment was done under thiopental (50 ㎎/㎏, IP) anesthesia. Captopril and indomethacin were injected into the right lateral cerebral ventricle. Arterial blood pressure and heart rate were recorded from the femoral artery. Intracerebroventricular (ICV) captopril (1 ㎎) caused a decrease in mean arterial pressure in both normotensive and 2K1C hypertensive rats. The depressor response to captopril was more sensitive in hyper-tensive rats than in normotensive rats. Indomethacin treatment (ICV, 200 ㎎) altered the depressor response to captopril neither in normotensive nor in hypertensive rats. These results suggest that the cardiovascular effect of renin-angiotensin system in the central nervous system may not be mediated via prostaglandin systems in normotensive and 2KlC hypertensive rats.

6주간의 淸暑益氣湯 經口投與가 에너지대사 및 호르몬 변화에 미치는 영향

최용어,강명신,유종만,이규성,오재근,조준용 韓國體育大學校附屬 體育科學硏究所 1994 韓國體育大學校附屬 體育科學硏究所論文集 Vol.13 No.1

The purpose of this study was to investigate the effects of chung-seo-ik-gi -tang administration on the metabolic responses and hormones in 18 healthy-male elite boxes. All subjects were divided randomly with two groups, Chung-sea-ik-gi-tang Group(N=18) and placebo group(N=18) and perfored with 70% of HR max using bycicle ergometer unfil exhaustion. During the submaximal exercise, heart rate was maesured every two min. The blood samples were collected from antecubital vein by 10ml syranges(6ml/each) before immediately after exhaustion, recover-10 min, recover-20 min and recover-30 min. The samples were to analyzed for the level of glucose, lactate, TG, TC, HDL-C, insulin and catecholamine. The results of various blood parameters were summarized as follow; l. Energy substrates (plasma glucose, TG, TC, HDL-C) changes in group C were significantly different from group P. Plasma glucose in group C was significantly lowered at recover-10 min compared to group P (P<0.05). and also TG, TC and HDL-C in group C were significantly increased after 3 weeks compared to group P (P<0.05) whereas. Lactate accumulation in group C was significantly decreased after 3 weeks compared to group P (P<0.05). 2. Plasma insulin level was not showed significant difference between two groups. But insulin depression tendency after 3, 6 weeks in group C was allevated compared to group P. Increasing rate of norepinephrine in group C at Post-exhaustion after 3weeks lowered compared to group P. Norepinephrine in group C at rest periods after 3 weeks showed significant difference compared to group C. The results indicated that Chung-seo-ik-gi-tang had the effects of ergogenic aids on fatigue resistance and recovery from exhaustive exercise at the level of 70% HR max.

금강유역 수질오염 실태조사

최신석,오희목,강명규,조통래,이규승,유종국,이영하 忠南大學校 環境問題硏究所 1988 環境硏究 Vol.6 No.1

조사 구역 상류 지점의 평균 수질은 pH가 7.1, DO가 8.3mg/ℓ, BOD가 1.7mg/ℓ, COD가 1.7mg/ℓ, SS가 15.4mg/ℓ, 분변성 대장균이 1.1x10³ MPN/100ml고 상수원 수 1급 내지 2급의 양호한 상태이고 하류지점의 수질은 pH가 6.8, DO가 7.7mg/ℓ, BOD가 2.2mg/ℓ, COD가 2.4mg/ℓ, 분변성 대장균이 1.7x10³MPN/100ml로 상수원 수 2급 내지 3급의 상태를 나타내 하류로 내려가면서 오염도가 증가하는 것으로 나타났다. 청주시의 영향을 크게 받는 미호천 하류의 평균수질은 pH가 7.2, DO가 6.3mg/ℓ, BOD가 16.2mg/ℓ, COD가 15.1mg/ℓ, 분변성 대장균이 1.6x10??MPN/100ml로 심각한 오염 상태를 보여 청주시와 대전시가 금강 본류의 주 수질 오염원으로 나타났다. 영양 염류 (NH₃-N, NO₂-N, NO₃-N, PO₄-P)와 무기성 유해 성분 (Cl-, CN-, F-)의 함량은 지천의 일부 지점을 제외하고는 극히 낮은 수준으로 검출되었으며, 유기인, 페놀류, PCB 성분은 조사기간 중 전혀 검출되지 않았다. 또한 Fe, Zn, Cu, Mn, Cr, Pb, Cd, Hg등의 중금속은 검출되지 않거나 하천 수질 기준 또는 식용수 수질 기준의 허용치를 초과하지 않는 양호한 수준으로 나타났다.

사상성 조류매트 고속산화지의 수질정화효율 평가

최선화,안열,오종민 경희대학교 2005 環境硏究 論文集 Vol.14 No.-

This study was carried out to evaluate of water purification in oxidation pond with filaments algae mat. It is the water treatment process in the small rural streams to remove the organic materials and nutrients. We used the filaments algae mat(FAM) which selectively predominate to prevent the additional contamination by algae outflow. The removal efficiencies of COD, SS, T-N and T-P in oxidation pond with filaments algae mat were -2.5%, 84.7%, 63.9% and 89.2%, respectively. The removal efficiencies of T-N and T-P which are nutrients index were high. Results of this study would help us to determine the possibility of using the water treatment on the contaminated small rural streams.

Macrophage Inflammatory Protein 1α가 T세포성장 및 CD4, CD8 발현에 미치는 영향

최종선,김오환 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.1

Macrophage inflammatory protein (MIP)-1αcytokine which produces wide range of bioctivities such as proinflammatory, immunomodulatory, and hematopoietic modulatory actions. To determine whether MIP-1αacts as a negative regulator on the functions of lymphocyte, [³H]-thymidine incorporation test and flow cytometric analysis were performed by using human tonsil T cell, human peripheral blood T cell, and murine cytolytic T lymphocyte (CTL) line CTLL-2, The mresults were as follow. 1. When human tonsil T lymphocytes were stimulated with anti-CD3 monoclonal antibody (mAb), rate of T cell proliferation was about four times increased. 200ng/ml of MIP-1α inhibited anti-CD3 mAb-mediated T cell growth as much as 60% (P<0.05)> 2. The suppression of human peripheral T cell proliferation produced by MIP-1αwas dramatic, but variable among T cells derived from different individuals (40%∼90%). 3. MIP-1αinhibited the mproliferation of murine CTL line CTLL-2 as much as 75%(P<0.001). 4. WHen the MIP-1αwas added to human peripheral T cell, cell proporation of CD4+ helper T cell and CD8+ CTL were not noticeably affected. The expression level of CD4, not of Cd8, however, was down regulated by MIP-1αtreatment (27%∼82%).