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        검색결과 422

        141.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A novel electrode for an NO gas sensor was fabricated from electrospun polyacrylonitrile fibers by thermal treatment to obtain carbon fibers followed by chemical activation to enhance the activity of gas adsorption sites. The activation process improved the porous structure, increasing the specific surface area and allowing for efficient gas adsorption. The gas sensing ability and response time were improved by the increased surface area and micropore fraction. High performance gas sensing was then demonstrated by following a proposed mechanism based on the activation effects. Initially, the pore structure developed by activation significantly increased the amount of adsorbed gas, as shown by the high sensitivity of the gas sensor. Additionally, the increased micropore fraction enabled a rapid sensor response time due to improve the adsorption speed. Overall, the sensitivity for NO gas was improved approximately six-fold, and the response time was reduced by approximately 83% due to the effects of chemical activation.
        4,000원
        142.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        겨울철 유휴 논토양에 헤어리베치를 재배 이용하여 바이오에너지 원료작물인 옥수수를 재배할 경우 화학비료와 제초제를 절감하고, 옥수수의 무경운 재배법을 개발하고자 수행하였다. 헤어리베치 피복 이용 옥수수 무경운 직파재배 시 재식밀도에 따른 옥수수의 간장, 경태 및 엽색도 등은 관행재배에비하여 감소하였으며, 착수고는 밀식할 경우 증가하는 경향이었다. 그 밖의 옥수수의 출사기는 헤어리베치를 피복한 처리구에서 관행재배구에 비하여 평균 3일 지연되었으며, 재식밀도가 높을수록 또는 시비량이 감소될수록 지연되었다. 한편 경작지에서 우점하는 잡초는 여뀌, 바랭이 및 피였으며, 헤어리베치 피복량 증가는 잡초 건물중을 감소시켰다. 바이오에탄올생산량은 헤어리베치를 피복한 처리구에서 관행과 비교하여58.9~89.8%까지 확보할 수 있었으며, 재식밀도가 낮거나 시비량이 적을수록 감소 정도가 크게 나타났다. 바이오에너지 작물인 옥수수를 친환경적으로 생산하는 방법 중의 하나로 헤어리베치를 피복하고 무경운 직파하여 시비량을 50% 감량하고, 재식밀도를 125,000 주 ha-1로 높이면 총 건물수량과 바이오에탄올량을 관행과 유사한 수준을 얻을 수 있을 것으로 판단되었다.
        4,000원
        143.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 재배비중이 가장 높은 큰느타리2호의 단점을 보완하고 버섯의 국내 육성품종 다양화하고 보급을 확대시키기 위해 육성한『곤지3호』의 주요 품종특성은 다음과 같다. 균사생장적온은 26~29℃, 버섯발생 및 생육적온은 14~18℃였으며, 배양일수 30일, 초발이소요일수 8일, 생육일수 5일로 전체 생육일수는 46일로 큰느타리2호와 대등하였다. 유효경수는 병당 2.4개, 대굵기 43.7mm, 대길이 123.8mm, 갓직경 64.9mm로 큰느타리2호와 비슷하였지만, 갓표면의 색도에 있어 명도값(L값)이 54.4로 큰느타리2호 58.2보다 낮아 전체 적으로 진회색을 나타내었다. 병당 수량 182g/1100cc 내외로 통계적 유의성은 없었으나 큰느타리2호 보다 높은 경향을 나 타내었다. 자실체의 단단한 정도(경도)는 7,790g/cm2 로 큰느타리2호 5,650g/cm2보다 높았고, 탄력성, 씹음성, 탄력성 등 전체적인 물리적 지표들이 큰느타리2호보다 높았다.
        4,000원
        144.
        2010.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to assess an alternative method to characterize indoor environmental factors by multiple indoor and outdoor measurements. Using a mass balance model and regression analysis, penetration factor and source strength factor were calculated using multiple indoor and outdoor measurements. This study was performed in 30 selected apartments in Seoul, Asan, and Daegu area which were constructed within 4 years and over 4 years, to measure the concentration of NO2 from July, 2004 to September. The results of this study are as follows. The average concentration of NO2 in Seoul, Asan, and Daegu area in the apartment constructed within 4 years are nitrogen dioxide 48.01㎍/m3 and in the apartment over 4 years are nitrogen dioxide 46.54㎍/m3. Mean ratios of indoor to outdoor NO2 concentrations are Seoul 0.99, Asan 0.83, Daegu 1.18. The deposition constant and the source strength of NO2 were 0.97±0.55 hr-1 and 16.33±12.30 ppb/h, respectively. In conclusion, indoor environmental factors were effectively characterized by this method using multiple indoor and outdoor measurements.
        4,000원
        145.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        금어초 'Potomac Red'를 200공 플러그 트레이에서 육묘하면서 NH4+과 NO3- 비율을 조절한 액비로 시비한 결과 초장, 생체중 및 건물중 모두 27 : 73(NH4+:NO3-)의 비율로 시비된 처리에서 가장 좋은 생장을 나타냈다. 파종 56일 후 식물조직의 질소와 인산함량은 27 : 73로 시비된 처리에서 각각 2.84% 및 0.39%로 가장 높게 분석되었다. 식물체내 K의 함량은 처리간 차이가 뚜렷하지 않았지만, 관비용액의 NH4+ 비율이 높아질수록 식물체의 Ca 및 Mg 함량이 감소하는 경향이었다. 상토의 pH는 파종 3주 후부터 NH4+:NO3-의 시비 비율에 따른 처리간 차이가 발생하여 8주까지 계속적으로 변하였으며, NO3-의 비율이 증가할수록 중성쪽으로, 그리고 NH4+의 비율이 증가할수록 산성쪽으로 변하였다. 상토의 EC는 NH4+ 의 비율이 증가할수록 높아졌고, 100% NH4+ 처리에서 파종 8주 후 2.2dS·m-1까지 상승하였다. NH4+:NO3-의 비율에 따른 상토중 질소 농도변화는 100 : 0의 비율에서 가장 높은 NH4+-N 농도를, 0 : 100에서 가장 높은 NO3--N 농도를 나타내었고, 상토의 인산농도는 처리간 뚜렷한 차이가 없이 식물이 생장함에 따라 토양의 인산농도는 낮아졌다. 그러나 관비용액의 NH4+ 비율이 높아질수록 상토의 K, Ca 및 Mg 농도가 높아지는 경향이었다. 관비용액의 NH4+:NO3-의 비율에 대한 식물생장 반응을 고려할 때 두 질소 비율로 27 : 73으로 조절하는 것이 플러그 육묘를 위해 바람직하다고 판단하였다.
        4,000원
        146.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 팔레놉시스의 생육에 적합한 배양액내 NO3-와 NH4+의 비율을 찾고 그리고 그 비율이 화경의 품질에 미치는 영향에 대하여 알아보고자 수행되었다. 실험에 사용된 배양액내 NO3-와 NH4+의 비율은 100%: 0%, 90%: 10%, 80%: 20%, 70%: 30%였다. 배양액내 팔레놉시스의 생육은NO3-만을 공급할 때보다 NO3-와 NH4+를 함께 공급할 때 생육이 증가하였다. 특히 NH4+의 비율이 10%일 때 생체중과 건물중이 가장 높았다. 그러나 배양액내 NH4+의 비율이 10%에서 30%로 증가함에 따라 지상부와 뿌리의 생육은 감소 되었다. 화경의 길이, 개체당 화경수와 소화수 모두 NH4+ 비율이 0%에서 10%로 증가함에 따라 높았으나 30%로 높아질수록 감소하였다. 즉, 팔레놉시스의 생육에 적합한 배양액내 NO3-와 NH4+의 비율은 90%:10%이었다.
        4,000원
        147.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,600원
        148.
        2010.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study presents residential indoor and outdoor exposure concentrations distributions of volatile organic compounds (VOCs, benzene, toluene, xylene) and nitrogen dioxide (NO2) in industrial area (case) and agricultural area (control) during 5 days. Concentrations of VOCs and NO2 were measured with passive samplers in residential indoor and outdoor. Most of benzene, toluene and NO2 mean concentrations in case area were higher than those in control area. Considering the indoor and outdoor ratios (I/O) were higher than 1, the residence might be have the sources of indoor air pollutants such as smoking and using of gas range. Residential indoor concentrations of benzene, toluene, and NO2 with indoor smokers were higher than those and without indoor smokers. In conclusion, it is suggested that personal exposures to air pollutants might be affected by indoor sources as well as outdoor pollutants emitted from industrial complex, and indoor air quality and outdoor air quality should be simultaneously considered to reduce the personal exposure to air pollutants.
        4,200원
        149.
        2010.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Semiconducting metal oxides have been frequently used as gas sensing materials. While zinc oxide is a popular material for such applications, structures such as nanowires, nanorods and nanotubes, due to their large surface area, are natural candidates for use as gas sensors of higher sensitivity. The compound ZnO has been studied, due to its chemical and thermal stability, for use as an n-type semiconducting gas sensor. ZnO has a large exciton binding energy and a large bandgap energy at room temperature. Also, ZnO is sensitive to toxic and combustible gases. The NO gas properties of zinc oxide-single wall carbon nanotube (ZnO-SWCNT) composites were investigated. Fabrication includes the deposition of porous SWCNTs on thermally oxidized SiO2 substrates followed by sputter deposition of Zn and thermal oxidation at 400˚C in oxygen. The Zn films were controlled to 50 nm thicknesses. The effects of microstructure and gas sensing properties were studied for process optimization through comparison of ZnO-SWCNT composites with ZnO film. The basic sensor response behavior to 10 ppm NO gas were checked at different operation temperatures in the range of 150-300˚C. The highest sensor responses were observed at 300˚C in ZnO film and 250˚C in ZnO-SWCNT composites. The ZnO-SWCNT composite sensor showed a sensor response (~1300%) five times higher than that of pure ZnO thin film sensors at an operation temperature of 250˚C.
        4,000원
        151.
        2010.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Indoor, outdoor, and personal nitrogen dioxide (NO2) exposures were studied in a population of housewives. Daily Indoor and outdoor NO2 concentrations were measured and compared with simultaneously personal exposures of 17 housewives for 7 consecutive days in 17 houses. In this study, indoor and outdoor NO2 samples at home were collected only while the housewives were at home samples. Time activity patterns and house characteristics were used to determine the effects of these factors on personal exposure. Since housewives spent their times in indoor houses with mean of 78.3%, their NO2 exposures were associated with indoor houses NO2 levels (r= 0.89) rather than outdoor NO2 level (r= 0.85). Contribution of indoor NO2 concentration on personal exposure was estimated by 70.77% by using of mass balance model. The close association between measured indoor NO2 concentrations and measured personal exposure and contribution of indoor NO2 concentration suggests that measuring indoor concentrations of NO2 in the home is sufficient to estimate personal exposure accurately.
        4,000원
        152.
        2010.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        UBVI CCD photometry is obtained for the Ruprecht 93 (Ru 93)region. We are unable to confirm the existence of an intermediate-age open cluster in Ru 93 from the spatial distribution of blue stars. On the other hand, we find two young star groups in the observed field: the nearer one (Ru 93 group) comprises the field young stars in the Sgr-Car arm at d ≈ 2.1 kpc, while the farther one (WR 37 group) is the young stars around WR 37 at d ≈ 4.8 kpc. We derive an abnormal extinction law (RV = 3.5) in the Ruprecht 93 region.
        4,000원
        153.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 실험은 Dendrobium nobile 계통의 교잡종인 'Hamana Lake Dream' X 'No. 55' 유묘의 기내삽목 시 증 식 및 생육에 알맞은 배지와 배양조건을 구명하고자 실시하였다. Hyponex배지보다 MS배지에서 생장이 잘되었는데 MS배지에 활성탄을 0.1과 1.0g/L 수준에서 첨가했을 때 줄기수와 엽장, 근수, 생체중이 양호 하였으나 2.0g/L이상에서는 감소하였으나 통계적 유의성은 없었다. MS배지에 agar, sucrose, peptone, gelite 를 농도별로 첨가한 실험에서는 agar 5g/L 첨가 시 줄기 길이와 엽폭, 생체중의 값이 높았고, 절간장과 근수는 sucrose 40g/L을 첨가했을 때 효과적이었다. 또한 줄기수와 엽수는 peptone 1g/L에서 효과적이었으 나 gelite는 모든 농도에서 대조구에 비해 저조하였다. 기내삽목 시 배양온도는 28℃가 알맞았고 동일한 온도조건에서는 MS배지가 Hyponex배지보다 더 효과적이었다. 또한 sucrose 농도별 실험에서는 28℃에서 40 g/L를 첨가하는 것이 좋았다.
        4,000원
        157.
        2010.05 구독 인증기관 무료, 개인회원 유료
        In 450mm wafers production environment for next generation Fab, one of the most significant features is the adoption of full automation to the whole manufacturing processes involved. The full automation system will prevent the workers from intervening the manufacturing processes as much as possible and increase the importance of each individual wafer noticeably, and thus require a more robust scheduling system for entire semiconductor manufacturing processes. The scheduling system for 450mm wafers production also should be capable of monitoring the status of each individual wafer and collecting useful Fab data in real time. In this study, we first analysis of cluster tool in 450mm wafers production environment, and then propose a real-time scheduling algorithm based on timetabling algorithm.
        4,000원
        158.
        2010.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Recently, one-dimensional semiconducting nanomaterials have attracted considerable interest for their potential as building blocks for fabricating various nanodevices. Among these semiconducting nanomaterials,, SnO2 nanostructures including nanowires, nanorods, nanobelts, and nanotubes were successfully synthesized and their electrochemical properties were evaluated. Although SnO2 nanowires and nanobelts exhibit fascinating gas sensing characteristics, there are still significant difficulties in using them for device applications. The crucial problem is the alignment of the nanowires. Each nanowire should be attached on each die using arduous e-beam or photolithography, which is quite an undesirable process in terms of mass production in the current semiconductor industry. In this study, a simple process for making sensitive SnO2 nanowire-based gas sensors by using a standard semiconducting fabrication process was studied. The nanowires were aligned in-situ during nanowire synthesis by thermal CVD process and a nanowire network structure between the electrodes was obtained. The SnO2 nanowire network was floated upon the Si substrate by separating an Au catalyst between the electrodes. As the electric current is transported along the networks of the nanowires, not along the surface layer on the substrate, the gas sensitivities could be maximized in this networked and floated structure. By varying the nanowire density and the distance between the electrodes, several types of nanowire network were fabricated. The NO2 gas sensitivity was 30~200 when the NO2 concentration was 5~20ppm. The response time was ca. 30~110 sec.
        4,000원
        159.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Scriabin`s output is often split into three periods.: Op. 1-29 (1886-1901), Op. 30-57 (1903-1908), and Op. 58-74 (1910-1914). He made a gradual transition to atonality, beginning as early as 1903. It is precisely between the second and third periods when we begin to observe a significant shift taking place in Scriabin`s way of conceiving his music. The purpose of this paper is to document the decline of tritone in Scriabin`s music primarily found in the transitional part of the composer`s musical career. While the theory was formulated by Russian music theorists, it has had a direct influence on various ways of understanding Scriabin`s complicated later works. The second chapter deals with the tritone in Scriabin`s transitional period. The most important harmonic function in Scriabin`s transitional music is a ♭Ⅱ-Ⅴ progression. The third chapter explores Scriabin`s music from the viewpoint of Russian music theory. I focus primarily on the work of three Russian theorists, namely, Yavorsky, Dernova and Kholopov, and how their works are related to the tritone of Scriabin`s music. Both Dernova and Kholopov carry over Yavorsky`s theory when discussing Scriabin`s problematic compositions, and one gets the sense. The merit of Russian music theory lies in the methodology. In particular, Scriabin`s Poeme, Op. 59, No. 1 is examined by using Russian music theorists`s views. The Russian theorists offer a new system of analysis, thereby allowing us to have an intimate and perspicuous understanding of the late Scriabin`s mechanics.
        7,700원
        160.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,600원