검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 121

        102.
        1996.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        HVPE(hydride vapor phase epitaxy)법을 이용하여 C(0001)면의 사파이어 기판위에 GaN 박막을 성장하였다. 1100˚C의 온도에서 박막의 성장률은 120μm/hr이었고, 사파이어 기판과 GaN사이의 격자상수와 열팽창계수차로 인하여 많은 크랙이 존재하였다. 두께가 20μm인 GaN의 (0002)면에 대한 X-선 회절피크의 반치폭은 576초 이었다. 10K의 온도에서 측정된 광루미네센스 스펙트럼에서는 강한 강도의 속박여기자에 의한 피크(I2)와 약한 강도의 도너-억셉터 쌍 사이의 재결합에 의한 피크가 나타났으며, 깊은 준위로부터의 발광은 검출되지 않았다. GaN 박막의 전기전도형은 n형 이었고, 전자이동도와 캐리어농도는 각각 72cm2/V-sec와 6x1018cm-3이었다.
        4,000원
        104.
        1995.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        AIN 완충층을 이용하여 대기압 유기금속에피텍셜 (MOVPE)법으로 사파이어 기판위에 성장시킨 AlGaN/GaN 이중 이종접합구조(double heterostructure : DH)의 고밀도 광여기에 의한 자외선 영역에서의 단면모드 유도방출 특성에 대하여 조사하였다. 실온에서 여기광 밀도 200kW/cm2에서 방출된 AlGaN/GaN DH의 유도방출 피크파장과 반치폭은 각각 369nm와 22.4meV이었으며, 80K의 온도에서는 각각 360.1nm와 13.4meV이었다. 고밀도 광여기에 의하여 단면모드 자외영역 유도방출을 얻기에 필요한 입사광 밀도의 임계치는 실온과 80K의 온도에서 각각 89kW/cm2와 44kW/cm2이었다.
        4,000원
        105.
        1995.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        AlGaN/GaInN 이중이종접합구조(double heterostructure :DH)를 대기압 유기금속기상에 피텍셜(MOVPE)법으로 AIN 와충층을 이용하여 사파이어 기판위에 성장하고, 실온에서의 광여기법에 의한 청색영역의 단면모드 유도방출특성과 편광특성을 조사하였다. 여기광원의 광밀도가 증가함에 따라 청색 영역에서의 유도방출 피크는 낮은 에너지 쪽으로 이동하였고, 유도방출 피크파장은 여기광밀도가 200kW/cm2일때 402nm 이었으며, 스펙트럼의 반치폭은 18meV 이었다. 또한 유도방출에 필요한 여기광밀도의 임계치는 130 kW/cm2 이었다. AlGaN/GaInN로부터 방출되는 유도방출 광은 임계치 이상에서 TE-mode로 편광 되었다.
        4,000원
        107.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to evaluate resistance of 10 different cowpea cultivars which were introduced from the United States against two major root-knot nematodes, Meloidogyne arenaria and M. incognita, that affect greenhouse crop cultivation in Korea. The results showed that the resistance of the tested cultivars to the root-knot nematodes varied with the cultivar. Texas Cream 40 showed moderate resistance to M. arenaria whereas the other cultivars were susceptible. Purple Hull Pinkeye and Texas Pinkeye Purple Hull were found to be resistant to M. incognita, whereas Mississippi Silver showed moderate resistance and the other cultivars were susceptible. As the cultivars exhibit resistance to M. arenaria and M. incognita, such cultivars resistant to root-knot nematodes should be considered during the cultivation of cowpea as a green manure crop.
        110.
        2014.10 KCI 등재 서비스 종료(열람 제한)
        Salt stress is one of the major abiotic stresses affecting the yield of ginseng (Panax ginseng C. A. Meyer). The objective of this study was to identify bio-marker, which is early responsive in salt stress in ginseng, using proteomics approach. Ginseng plants were exposed to 5 ds/m salt concentration and samples were harvested at 0, 6, 12 and 18 hours after exposure. Total proteins were extracted from ginseng leaves treated with salt stress using Mg/NP-40 buffer and were separated on high resolution 2-DE. Approximately 1003±240 (0 h), 992±166 (6 h), 1051±51 (12 h) and 990±160 (18 h) spots were detected in colloidal CBB stained 2D maps. Among these, 8 spots were differentially expressed and were identified by using MALDI-TOF/TOF MS or/and LC-MS/MS. Ethylene response sensor-1 (spot GL 1), nucleotide binding protein (spot GL 2), carbonic anhydrase-1 (spot GL 3), thylakoid lumenal 17.9 kDa protein (spot GL 4) and Chlorophyll a/b binding protein (spot GL 5, GL 6) were up-regulated at the 12 and 18 hour, while RuBisCO activase B (spot GL 7) and DNA helicase (spot GL 8) were down-regulated. Thus, we suggest that these proteins might participate in the early response to salt stress in ginseng leaves.
        113.
        2010.10 KCI 등재 서비스 종료(열람 제한)
        본 논문에서는 상선사관을 위한 실습선에서의 효율적으로 실습 가능한 적정실습인원 및 설비 개선에 대한 연구를 수행하였다. 연구 수행을 위해 상선해기사를 양성하는 교육기관의 실습선에서 교육중인 실습생과 교원을 대상으로 적정 교육 인원에 대한 설문을 실시하고 실습 면적을 포함한 교육 설비에 대한 전반적인 제원 조사를 실시하여 이번 연구에 대한 기초자료를 준비하였다. 또한 연구의 신뢰성을 향상시키기 위해 인간공학에서 제시하는 공간개념을 도입하여 이번 연구에 적용하였다. 이러한 기초 연구 자료와 개념을 통해서 항해통합콘솔 장치라는 항해 실습생을 위한 교육 설비와 기관실습생을 위한 설비인 기기 정비 운용 실습교육장을 제안하였다. 그리고 제시된 설비에서 교육 받을 수 있는 적정 인원을 제시하였다.
        114.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        Flavonoid는 식물의생장과 발육, 미생물과 해충에 대한 방어 인간에 대한 약리적효과(향균,항바이러스, 항알레 르기, 항염증,암발생율감소,중금속체외배출등)강력한 항산화활성 등으로 최근 그 중요성과 활용성이 강조되 고있다. 본연구는 콩에 플라보노이드와 관련된 유전자를 밝히고 그 이용성을 높이고자 연구를 수행하였다. 연구결과를 요약하면 실험재로로 쓴 특정한 콩에 전체 probe갯수 4만여개에서 플라보노이드와 관련된 probe 갯수 124개를 찾았다.그리고 Genbank가 같은 probe집단을 합쳐서 EST갯수가 64개로 밝혀졌다. 그중에서 염색 체위치와 번호 밝혀진 EST는 34개, 밝혀지지않은 염색체위치와 번호는 30개로 나타났다. 이를 토대로 Gene을 밝힐것이다. 이 연구의 궁극적인목적은 플라보노이드계 유전자 구명이다. 그리고 구명된 유전자를 통해서 그이용성을 높이고 활용하는데 있다.
        115.
        2007.02 KCI 등재 서비스 종료(열람 제한)
        Long-term passive diffusive samplers(PDS) have been used to measure NO2 and SO2 concentrations at 21 sampling sites in Daejeon, Korea during the period of January 2000 - December 2002. The spatial distributions of annual NO2 and SO2 concentrations were mapped. Average annual NO2 concentration over the sampling period was 28.5±12.5 ppb, ranging from 1.2 to 81.7 ppb. Average annual SO2 concentration over the sampling period was 7.7±4.8 ppb, ranging from 0.6 to 26.8 ppb. On average, NO2 concentration was approximately 5.8%(1.6 ppb) larger in 2002. SO2 concentration was decreased by 13%(1.1 ppb) during the sampling period. The seasonal variation of NO2 and SO2 concentration was observed with a tendency to be higher in fall and winter. NO2 and SO2 concentrations measured at different site types(patterns of land use) show significant difference. The observed difference in concentration was associated with difference in emissions of NO2 from motor vehicles and SO2 by non-traffic fuel consumption for heating.
        117.
        2002.07 KCI 등재 서비스 종료(열람 제한)
        The effects of noble gas (such as helium, neon, argon, krypton, and xenon) on the sonolytic decomposition of water and 2-methyl-2-propanol(t-butanol) with 200 kHz high power ultrasound were investigated. The physical properties of the noble gas have an effect on the formation rate of products (H2O2, H2, O2) and the decomposition rate on the sonolytic decomposition of water. The pyrolysis products, such as methane, ethane, ethylene, and acetylene are formed during the sonolytic decomposition of t-butanol. From the estimation of the ratio [C2H4 + C2H2] / [C2H6], the cavitation temperature would be varied by the used noble gas. In all cases for the sonolytic decomposition of water, t-butanol, and diethyl phthalate, the decomposition rates were xenon > krypton > argon > neon > helium with a significant difference and were closely correlated with the formation rate of OH radical and high temperature inside the cavitation bubble under each noble gas.
        119.
        1998.08 KCI 등재 서비스 종료(열람 제한)
        Precipitation samples were collected at sixteen sites in Northeast Asia from June 1995 to February 1997, and were analysed for the anions SO_4^2- NO_3^- and Cl^- and for the cations Na^+, NH_4^+, K^+, Mg^2+ and Ca^2+ in addition to pH and conductivity measurements. The quality assurance of chemical composition data was checked by considering the ion balance evaluating by │h│ value and the conductivity balance. The sum of cation concentrations were slightly greater than the sum of anion concentraions. For the anions, SO_4^2- clearly dominates in most of sampling sites whereas Cl^- is more abundant in coast and rural sites in Japan. For the cations, Ca^2+ and NH_4^+ are generally the more abundant ions except when sources of Na^+ exist. The contribution rate of nss-SO_4^2- and NO_3^- to acidity are about 70% and 10-30%, respectively. The neutralizing capacity by a major neutralizing cations such as NH_4^+ and nss-SO_4^2+ are above 98%(heavy polluted and urban sites in China), above 70%(urban sites in Japan and in Korea, coast sites in China) and above 60%(rural sites in Japan and in Korea), respectively.
        120.
        1998.06 KCI 등재 서비스 종료(열람 제한)
        The structure such as building and cultural properties was composed of various materials like wood, metal and stone that have been utilized and exposed to air, wind and rain for a long time. However, because of their special characteristics as structure, collecting of samples that may involve their destruction cannot be permitted, ever for material analysis. Therefore, in order to study the influence of atmospheric pollution on structure, atmospheric corrosion tests were achieved by making use of materials(bronze, ancient copper, copper, steel and marble) in field exposure tests. Atmospheric exposure sites are selected from places which are characterized by urban, rural, industrial and marine environments in Northeast Asia. According to the results of atmospheric corrosion tests; The corrosion rates of industrial sites in china were more serious than other sampling sites. In the correlation of meteorological factors, wet hours was defined as integrated hours under that atmospheric temperature is above O℃ and relative humidity in above 80% that has a great influence on corrosion tests of materials in case of a short time. The relative humidity was above about 75% that resulted in great increase of corrosion rates. In the esimation of corrosion rates between materials, corrosion rates of steel was about thirty times and decuple larger than that of other materials excluding marble in unshelterd exposure and in sheltered exposure.
        6 7