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        검색결과 4

        1.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the catalytic combustion of propionaldehyde, which is an Offensive Odorant Substance assigned by the Korean Ministry of Environment (KMOE), over alumina-supported manganese oxide (Mn/Al2 O3) catalysts was investigated. The combustion reaction was carried out in a fixed-bed reactor at the temperature range of 200 ∼340 ℃. Mn/Al2O3 catalysts with Mn loadings ranging from 3.9 to 18.3 wt.% were prepared by impregnation method. The physicochemical characteristics of the catalysts were analyzed by X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM) and Brunauer-Emmett-Teller (BET). The Mn crystalline phases of the Mn/Al2O3 catalysts were identified as α-Mn2O3 and β-MnO2. Mn oxides were covered on γ-Al2O3 supports with an average diameter of around 1 μm. With the increase of Mn loadings, the BET surface areas, pore volumes and average pore diameters of the Mn/Al2O3 catalysts decreased. The catalytic activities of Mn/Al2O3 catalysts increased as the Mn loading was increased from 3.9 wt.% to 18.3 wt.%. The catalyst with 18.3 wt.% Mn loading was able to achieve 100% propionaldehyde conversion at 260 ℃. For the same temperature, a lower Gas Hourly Space Velocity (GHSV) and a lower propionaldehyde concentration promote the complete combustion of propionaldehyde.
        4,000원
        2.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objectives of this study were to analyze the characteristics of odor in the major facilities of a fishery industrial complex using the air dilution olfactory method and the instrumental analysis method. The results indicate that although the limit of dilution to threshold (D/T) ratio in the major facilities is not regulated by the Odor Emission Standard, the mean (D/T) ratio over than 3,000 which is higher than the limit in the outlet of industrial area 3 times was found at three sampling sites. In the case of the concentration of the malodorous compounds, ammonia concentration is higher than any other odor compounds. The methyl mercaptan, n-Butyric acid and hydrogen sulfide as the main pollutants are confirmed by the odor quotient (OQ). In our study, it is showed a moderately good correlation between the (D/T) ratio and the sum of OQ. By this result, we can estimate the odor characteristics and evaluate the potential impact of each odor compound. In addition, we consider that it will affect the people"s normal life and even cause for complaint around the boundary area by the diffusion of odor.
        4,000원
        3.
        2022.07 KCI 등재 서비스 종료(열람 제한)
        The latest aerospace technology is important for the stable flight of a launch vehicle, but weather conditions on the day of launch are also one of the essential factors for successful launch campaign. If a launch vehicle is directly struck while preparing to take off from the launch pad on the day of launch or the electronic device are damaged by induced current during flight of the launch vehicle, this means launch failure and can lead to enormous national loss. Therefore, for a successful launch campaign, it is necessary to analyze the lightning detection characteristics of the Naro Space Center. In this study, the seasonal factors of the lightning that occurred over the Naro Space Center from 2003 to 2017, the influence of the polarity, and the correlation with the lightning intensity was confirmed. As a result, there was a high probability of intensive occurrence of multiple lightning strikes in summer, and a high proportion of positive (+) lightning strikes in winter. Lastly, in the distribution of the number of lightning strikes, an average of 2.0 to 2.5 negative (-) lightning strikes occurs in the coastal regions of the South and West Seas when one flash happens.
        4.
        2019.12 KCI 등재 서비스 종료(열람 제한)
        Successful launch requires state-of-the-art launch vehicle technology and constant test operations, However, the meteorological threat to the launch vehicle flight trajectory is also an important factor for launch success. Atmospheric stability above the Naro Space Center at the this time is very important, especially because the initial flight operation can determine the success of the launch. Moreover, during the flight of launch vehicle with rapid pressure and thrust into the atmosphere, convection activity in the atmosphere may create environmental conditions that cause severe weather threats such as thunderstorms. Hence, studies of atmospheric instability characteristics over the Naro Space Center are a necessary part of successful launch missions. Therefore, the main aims of this study were to (1) verify the atmospheric stability index and convection activity characteristics over the Naro Space Center using radiosonde data observed from 2007 to 2018 by the Naro Space Center, (2) analyze changes in the atmospheric stability index according to monthly and seasonal changes, and (3) assess how the calculated atmospheric stability index is related to actual thunderstorm occurrence using statistical analysis. Additionally, we aimed to investigate the atmospheric characteristics above the Naro Space Center through the distribution chart of the atmospheric stability index during summer, when convection activity is highest. Finally, we assessed the relationship between lightning occurrence and unstable atmospheric conditions, through predictability analysis performed using the lightning observation data of the Korea Meteorological Administration.