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>

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

비디오 흉강경을 이용한 자연기흉의 수술요법

권오춘,안욱수 대구효성가톨릭 대학교 1997 연구논문집 Vol.54 No.2

Primary spontaneous pneumothorax has an annual incidence of 9 cases per 100,000 populations, especially high incidence in young adults. Thoracoscopic surgery is not new, but its applications to chest surgery have been more increasing with advanced video technology and instrumentation. We performed 15 cases of bullectomy using video-assisted thoracoscopy(VATS) for patients of pneumothorax. The mean age of patients was 25.1±7.6 years old, 105.5±40.1 minutes of mean operation times, and 3.2±1.9 days of postoperative tube indwelling time. Postoperative complications were persistent air leakage in one case, which was converted to open thoracotomy later, and recurrence of pneumothotax in one case. Video-assisted thoracoscopic bullectomy is effective alternative to thoracotomy for treatment of pneumothorax in terms of short hospital stay, less morbidity, low rate of recurrence, less pain, and good cosmetic results. But objective comparison with mini-thoracotomy will be needed in many aspects.

Chlorella vulgaris의 세포막에서 일어나는 Glycine 흡수과정에 관한 연구

權五溶,辛昌男,吳炅煥,李錦洙 충남대학교 자연과학연구소 1981 忠南科學硏究誌 Vol.8 No.1

In order to datemine that glycine uptake in the cell membrane of Chlorella vulgaris is depend on the specificity of substrate and energy required, it has been investigated on the reaction velocity of glycine and certain carrier. Some effects on the transmural fluxes of glycine across the cell membrane were also detemined. 1. The time course of glycine uptake was a linear function of time to early 10 min, and increased in the steady state slowly. 2. Glycine influx had shown apparent affinity in the range of 0.001 mM to 10 mM solution of glycine and followed Michaelis-Menten Kinetics(Km-0.16 mM, Vmax=0.31 nM2.0x10^7 cells min). 3. Glycine influx with 1 mA IAA was reduced about 50 percentage, suggesting that glycine uptake process is energy-dependent. 4. Glycine uptake was inhibited by glutamic acid, alanine, phenylalanine, proline, and methionine with the exception of histidine. It was suggested that the inhibition was competeted with some amino acids described above.

600합금의 미세조직 변화 및 SCC거동에 미치는 Ce 첨가의 영향

권오철,이용선,임연수,정만교,김정수 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.1

High purity model alloys with major composition Ni-15Cr-9Fe-0.03C (600CEO) and Ni-15Cr-9Fe-0.03C-0.04Ce (600CE4) were produced. Using these model alloys the effect of alloying element Ce on the SCC behavior of Alloy 600 was evaluated in a caustic solution. To obtain carbides precipitated on grain boundaries, the thermal treatment was performed on both the solution annealed model alloys. Microstructural examinations using SEM and TEM EDX showed that the same structural carbides, Cr_(7)Cc₃, were precipitated on both the alloys and no significant difference in the amount of Cr depletion along grain boundaries was observed between the two model alloys. However, it was shown that the coverage of grain boundary carbides was higher in the Ce-bearing alloy (600CE4). The SCC susceptibility of the alloys was investigated in 40%NaOH solution at 315℃. Being evaluated in terms of the maximum crack depth, the SCC susceptibility of the alloy turned out to be reduced by the addition of Ce. The increased resistance to the SCC in the alloy 600CE4 was considered to be attributable to the increased coverage of grain boundary carbides. (Received September 30, 2004)

3차원 디지털 모형을 이용한 양악 치조골 전돌자의 치열궁 특성 연구

권오원,이수경,성재현 대한치과교정학회 2006 대한치과교정학회지 Vol.36 No.1

최근 안모의 심미성이 중요시되면서 구순 돌출로 인한 비심미성을 해소하고자 내원하는 양악 치조골 전돌자의 수가 증가하는 추세이다. 그러나 이러한 환자에 대한 연구는 많지 않으며 특히 모형을 이용한 연구는 극히 적다. 모형을 이용하는 연구는 주로 손으로 직접 계측하거나 2차원 평면에서 컴퓨터를 이용하여 측정하였으나 근래에 3차원 레이저 스캐너가 도입되면서 모형을 이용한 연구를 좀 더 빠르고 간편하면서도 정확하게 할 수 있게 되었다. 이 연구는 3차원 디지털 모형을 이용하여 양악 치조골 전돌자의 치열궁 특성을 알아보기 위한 것이다. 양악 치조골 전돌자 20명과 정상교합자 20명을 대상으로 치아 크기, 치열궁 폭경 및 치열궁 길이, 치열궁과 구개의 형태를 비교하여 본 결과 양악 치조골 전돌자는 정상교합자보다 치아 크기가 크고, 하악 견치간 폭경 및 제1소구치간 폭경이 크며 치열궁 길이가 길었다. 그리고 치열궁 형태와 구개 형태에서 정상교합자와 차이를 보였다. Recent beauty trends have caused an increase in the number of bialveolar protrusion patients seeking treatment of lip protrusion. But studies of these patients are not common. Studies using their dental models are especially rare. Dental models have been measured manually or through a computer by digitizing two dimensional images of models. Nowadays, we are able to study dental models more easily and accurately by utilizing the three-dimensional (3-D) laser scanner in dentistry. An investigation was carried out to evaluate the characteristics of the dental arch in a bialveolar protrusion group in comparison with a normal group using 3-D digital models. The normal group was composed of 20 subjects who were selected from students of the School of Dentistry, Kyungpook National University. The bialveolar protrusion group was composed of 20 subjects who visited for treatment at the Department of Orthodontics, Kyungpook National University Hospital. Tooth size, arch width and arch length were measured digitally, and arch shape and the shape of the palate were drawn. Based on the results of this study, the differences of the arch characteristics in the bialveolar protrusion group were that the size of the teeth was larger, mandibular canine width and 1st premolar width were wider, and arch length was longer than in the normal group. And there were differences in the arch shape and the shape of palate between the bialveolar protrusion and normal groups.

여학생 동복 하의 착용시의 생리반응과 주관적 착용감

권수애,오미경,강미영,송혜원,박진채,권리현 충북대학교 교육 ·생활연구소 생활과학연구센터 2002 생활과학연구논총 Vol.5 No.-

In this study, physiological responses and subjective sensations were investigated depending on various high school girls' lower cloth uniform in winter. Four healthy young women were selected, and they wore same underwear and jacket. The types of lower cloth were tight skirt+stocking, flared skirt+stocking, tight skirt+legings+socks, flared skirt+legings+socks, and slacks+socks. The results were as follows: 1) The effect of the type of lower cloth in winter on the skin temperature, humidity inside clothing and subjective sensations were significant. 2) It is desirable for high school girls to wear slacks in winter, Since physiological responses and subjective sensations of slacks are superior to those of skirts. 3) It is desirable for high school girls to wear flared skirt, legings, socks in winter, Since insulation and subjective sensations of flared skirts are superior to those of tight skirts.

압전 비틀림 파동 변환기 제작 및 평가

권오수,김진오 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.4

봉에서 전파하는 비틀림파를 발생시키는 압전 비틀림 파동 변환기를 제작하였다. 비틀림 파동을 발생시키는 원리는 원주방향으로 분극된 압전 원판에 인가된 두께 방향 전압에 의해 나타나는 원주방향 전단운동이다. 압전 비틀림 원판을 제작한 후, 공진 주파수를 낮추기 위하여 랑주방(Langevin)형 비틀림 변환기를 제작하였다. 제작된 변환기들의 공진 주파수를 측정한 결과, 해석에 의해 예상된 특성과 잘 일치하였다. Piezoelectric torsional transducers have been fabricated to generate waves in a rod. The principle of generating torsional wave is based on the use of the circumferential shear motion derived by axial voltage exerted on the piezoelectric disk poled in the circumferential direction. The natural frequency of the piezoelectric torsional disk has been reduced by fabricating Langevin-type torsional transducers. The natural frequencies of the fabricated transducers have been measured and have shown good agreement with the characteristics predicted by analysis.

Benzo(a)pyrene에 의해 유도된 간기능장해에 미치는 자근 추출액의 영향

윤수홍,박은주,오관현,정영건,권오진 효성여자대학교 부설 한국환경위생연구소 1994 환경위생연구 Vol.4 No.1

민간에서 주로 사용되는 약용식물들 중 간독성의 발현 저해 및 간기능 보호효과가 우수한 약물을 찾아 임상적인 약효를 밝혀보고자 하는 실험 과정으로 탄소화합물의 불완전 연소 및 열분해에 의해 생성되는 간장해 물질인 benzo(a)pyrene 으로 유도한 rats 의 간독성 발현에 미치는 자근 수침액의 예방 및 치료효과를 실험한 결과 자근 수침액의 투여는 B(a)P 투여로 현저하게 증가된 혈청 및 간장의 AST, ALT, LDH, ALP 활성을 유의성있게 감소시켰고, B(a)P투여로 증가한 혈청 total cholesterol 및 phospholipid 함량 역시 감소시킬 수 있었으나 그 효과는 현저하지 않았다. 즉, 자근 수침액의 투여는 B(a)P에 의한 간독성 발현을 유의성 있게 감소시켰으며 그 효과는 전처리가 후처리에 비해 우수하였다. The present study was undertaken to compare the pharmacologicalactivities of cn de Lithospermi Radix reported with the clinical uses in the orientalmedicine. Crude Lithospermi Radix uesd for the treatment of burn, eczema,blister, diuretic, scarlet fever and septicemia as antipyretic, antidotic and antiph-logistics. Therefore we tested the effects of Lithospermi Radix water extracton the liver-protective activities in the rats. The results obtained from enzymeassay, measurement of serum and liver alanine·aspartate aminotransferase(ALT, AST) and lipid composition indicated that Lithospermi Radix water extractshowed significant liver-protective activities against benzo(a)pyrene-induced he-patotoxicity.

학습목표 성취를 위한 CAI 프로그램의 개발

주경수,권오석 순천향대학교 1994 논문집 Vol.17 No.1

We planned 5 grade mathematics fraction by CAI program in order to help the accomplishment of learning by the correct knowledge of learning objection. We are embodied by making use of GREAT with authoring tools. This was that heteogeneous students were able to shorten learning period in the circumstances of learning in a class room, to extend remarkably personal ability with individual learning adjust to each student. In addition to, we made a program so as to compensate for high level process for superior student, the supplementation of learning less for inferior students.