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.

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>

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.

內燃機關의 排氣騷音이 性能에 미치는 影響

吳栗權,張熙碩,吳炯俊,車京玉 明知大學校 産業技術硏究所 1988 産業技術硏究所論文集 Vol.7 No.-

The theoretical analysis of the exhaust noise of an internal combustion entwine contains various difficult factors. The exhaust system is closely related with these problems, that is, the resistance of tile exhaust system is a factor governing the fuel economy and dynamic performance of an internal combustion engine, while exhaust noise and radiated noise from the system are one of the main factor affecting the quietness of an internal combustion engine and also one of the main sources of external noise of all internal combustion engine. Reducing tile resistance and lowering the exhaust and radiated noise are contracdictory requirements and it has been considered difficult to satisfy these requirements simultaneously. Almost all the studies on the attenuation characteristics of a muffler are an analysis based on the assumption that the time of intake-exhaust valve opening - closing is deadpoint. This paper introduces a practical exhaust system for internal combustion engine newly developed as the result of studies on the reduction of the exhaust system, pulsating noise and draft noise.

우리나라 해외진출기업의 시장진입방식 결정요인에 관한 연구 : 거시적 국가환경요인을 중심으로

오경희,김정포 釜山外國語大學校國際通商硏究所 2002 國際經營論集 Vol.17 No.-

To choose a proper entry mode for foreign market is a very critical for decision makers of firms. It leads the firm's success and failure on that markets in the future. Because of the importance of choosing the right entry mode, and the burden of resources, time, and efforts the company should have, it is very difficult and painful for decision maker to change one entry mode to another. The objective of this study explored on the macroeconomic level, which encompasses economic, political, cultural and geographic variables, as the determinants on the entry mode choice. To test the hypothesis empirically, correlation analysis was performed to identify the relationship among variables. In addition, the binominal logistic regression analysis was conducted to verify the relative contribution of each variables. SPSS PC+ was used for analysing data from questionnaires and second sources. The results of the analyses are as follows; First, the cultural distance factors affected significantly the entry mode choice. Second, size of the market factors affected the entry mode choice. The results indicated the necessity to acknowledge the cultural difference between the host country and home country, and the size of the market of the host country also is a factor affecting significantly the entry mode choice. On the other hand, this study indicated that country-related risk, government polices and market competitive iintensity are non-significant factors on choosing location.

동중국해의 해수순환과 대한해협 유량의 계절변화

오경희,방익찬,노홍길 제주대학교 해양연구소 1996 해양자원연구소연구보고 Vol.20 No.-

To study on the relation between the circulations in the East China Sea(ECS) and seasonal variations of volume transport through the Korea Strait, CSK data (1965-1989) are analyzed. As a result, the increase of volume transport in the Korea Strait in summer seems to be due to the seasonal variations of the water mass distributions in ECS. Kuroshio waters out of the shelf break has little seasonal variations. As outflowing to the south sea of Kyusyu. it has little influence on the Korea Strait. Tsushima Warm Water(TWW) flowing along the shelf break to the Korea Strait has no significant seasonal variations. But, the surface waters in ECS show clear seasonal variations : high-temperature and low-salinity in snmmer and low temperature and high salinity in winter. ECS deep waters have much smaller seasonal variations than the surface waters. Thus, seasonal variations of ECS could be mainly due to the surface waters. The distributions of surface waters in summer coincide with the area of Yangzee coastal waters from Yangzee river to the Korea Strait. It means that the seasonal variation of volume transport in the Korea Strait could be caused by the input of Yangzee coastal waters.

해외직접투자기업의 정치적 위험인식에 관한 연구 : 부산 ·경남소재 해외직접투자기업을 중심으로

오경희 釜山外國語大學校 1997 外大論叢 Vol.17 No.1

This paper reports preliminary results of a study on political risk recognition in FDI firms. The hypotheses is that the FDI firm's and industry's characteristics will have an effect on the degree of attention to political risk. A mailed survey of 52 firms was followed up by personal interviews with managers partly. The major results of this study are as follows; First, the primary information sources to evalulate the political risk was subsidiary managers, regional managers and mass media(newpapers, business periodicals etc.,). Second, the assessment and evaluation of social and political environments were found to be reactive rather than active. The process is more motivated by external event than by internal event and few firms conduct routinely the process. Third, Korean FDI firms manage the political risk by irrational and unsystemtic method. The most favorite method to manage the political risk was lobby. Forth, with regard to FDI firms characteristics, there was a relationship between the size of FDI firms and the level of recongition of political environments. Also, the relationship between the percent of equity ownership and the recognition level of political environments was significant. But there was not significant relationship between the percent of host country sales and the recognition level of political risk. With regard to FDI firms industry characteristics, the significant relationship between the industry type of FDI firms and the recognition degree of political risk was not. But there was significant relationship not only between the level of technology within the industry and the level of recognition degree but between the level of competition in the industry and the level of recongition degree of political risk.

중·고등학교 아랍어 교재 집필 및 교재 내용에 관한 연구 보고서

오명근,송경숙,전완경,사희만,이규철,조희선,정규영,최진영 한국아랍어아랍문학회 1999 아랍어와 아랍문학 Vol.3 No.1