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        검색결과 5

        1.
        2022.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        For the selective catalytic reduction of NOx with ammonia (NH3-SCR), a V2O5WO3/TiO2 (VW/nTi) catalyst was prepared using V2O5 and WO3 on a nanodispersed TiO2 (nTi) support by simple impregnation process. The nTi support was dispersed for 0~3 hrs under controlled bead-milling in ethanol. The average particle size (D50) of nTi was reduced from 582 nm to 93 nm depending on the milling time. The NOx activity of these catalysts with maximum temperature shift was influenced by the dispersion of the TiO2. For the V0.5W2/nTi-0h catalyst, prepared with 582 nm nTi-0h before milling, the decomposition temperature with over 94 % NOx conversion had a narrow temperature window, within the range of 365-391 °C. Similarly, the V0.5W2/nTi-2h catalyst, prepared with 107 nm nTi-2h bead-milled for 2hrs, showed a broad temperature window in the range of 358~450 °C. However, the V0.5W2/Ti catalyst (D50 = 2.4 μm, aqueous, without milling) was observed at 325-385 °C. Our results could pave the way for the production of effective NOx decomposition catalysts with a higher temperature range. This approach is also better at facilitating the dispersion on the support material. NH3-TPD, H2-TPR, FT-IR, and XPS were used to investigate the role of nTi in the DeNOx catalyst.
        4,300원
        2.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Heatwaves are one of the most common phenomena originating from changes in the urban thermal environment. They are caused mainly by the evapotranspiration decrease of surface impermeable areas from increases in temperature and reflected heat, leading to a dry urban environment that can deteriorate aspects of everyday life. This study aimed to calculate daily maximum ground surface temperature affecting heatwaves, to quantify the effects of urban thermal environment control through water cycle restoration while validating its feasibility. The maximum surface temperature regression equation according to the impermeable area ratios of urban land cover types was derived. The estimated values from daily maximum ground surface temperature regression equation were compared with actual measured values to validate the calculation method’s feasibility. The land cover classification and derivation of specific parameters were conducted by classifying land cover into buildings, roads, rivers, and lands. Detailed parameters were classified by the river area ratio, land impermeable area ratio, and green area ratio of each land-cover type, with the exception of the rivers, to derive the maximum surface temperature regression equation of each land cover type. The regression equation feasibility assessment showed that the estimated maximum surface temperature values were within the level of significance. The maximum surface temperature decreased by 0.0450˚C when the green area ratio increased by 1% and increased by 0.0321˚C when the impermeable area ratio increased by 1%. It was determined that the surface reduction effect through increases in the green area ratio was 29% higher than the increasing effect of surface temperature due to the impermeable land ratio.
        4,300원
        3.
        2015.04 구독 인증기관·개인회원 무료
        The development and fitness of insects depend on the temperature to which they are exposed. The thermal windows are defined as the temperature range between the minimum and maximum rate of development for individual species. The intrinsic optimal temperature for development proposed by Ikemoto is one of important factors that determine the fitness of optimum life history. The temperature requirements for development of 65 species from five orders of insects was obtained from several journals. The minimum and maximum rate of development was estimated using empirical models. The temperature tolerance range of enzyme activation was estimated using Shape-Schoolfield-Ikemoto (SSI) model. The mean and range of intrinsic optimal temperature were 20.89°C and 15.7~27.7°C. The mean intrinsic optimal temperatures of Hemiptera and Endopterygota (Coleoptera, Diptera, Hymenoptera and Lepidoptera) were 20.97°C and 20.71°C. The mean and range of thermal windows were 25.59°C and 16.69~36.13°C. The mean thermal windows of Hemiptera and Endopterygota were 25.53°C and 25.62°C. also not much different. Each species of insects had a limited temperature range for development. It is needed further studies for understanding the ecological, physiological and evolutionary response of insects to their thermal environments.
        4.
        2019.07 KCI 등재 서비스 종료(열람 제한)
        This study investigated the relationship between heat-related illnesses obtained from healthcare big data and daily maximum temperature observed in seven metropolitan cities in summer during 2013~2015. We found a statistically significant positive correlation (r = 0.4~0.6) between daily maximum temperature and number of the heat-related patients from Pearson's correlation analyses. A time lag effect was not observed. Relative Risk (RR) analysis using the Generalized Additive Model (GAM) showed that the RR of heat-related illness increased with increasing threshold temperature (maximum RR = 1.21). A comparison of the RRs of the seven cities, showed that the values were significantly different by geographical location of the city and had different variations for different threshold temperatures. The RRs for elderly people were clearly higher than those for the all-age group. Especially, a maximum value of 1.83 was calculated at the threshold temperature of 35℃ in Seoul. In addition, relatively higher RRs were found for inland cities (Seoul, Gwangju, Daegu, and Daejeon), which had a high frequency of heat waves. These results demonstrate the significant risk of heat-related illness associated with increasing daily maximum temperature and the difference in adaptation ability to heat wave for each city, which could help improve the heat wave advisory and warning system.
        5.
        2015.10 KCI 등재 서비스 종료(열람 제한)
        This study tried to compare and analyze the thermal comfort index according to GVZ of school green space. For the analysis, this study performed a correlation analysis with weather elements by measuring and calculating UTCI, PMV, and WBGT according to GVZ. GVZ was in the order of Type 3 (5.68 m3/m2) > Type 2 (4.71 m3/m2) > Type 1 (3.37 m3/m2). The average temperature and solar radiation, surface temperature, globe temperature among weather characteristics was in the order of Type 1> Type 2 > Type 3. The UTCI in the school green space was in the order of Type 1 (33.95°C) > Type 2 (33.68°C) > Type 3 (32.73°C). At Type 3 that the GVZ is higher than other Types, it is belongs to range of 26~33°C which gets normal heat stress, and other Types belong to range of 33~38°C which gets strong heat stress. The PMV was in the order of Type 1 > Type 2 > Type 3, and the estimated rate of unsatisfaction was appeared as 100%, so it is uncomfortable even in the school green space that it requires measure on heat wave. The WBGT was in the order of Type 1 > Type 2 > Type 3. The result of the correlation analysis according to the heat comfort index shows that, the higher the green ratio and GVZ are, the UTCI has negative relationship, and PMV and WBGT were analyzed as have no relationship according to green characteristics, but this result was considered as measured at green space when the temperature was at its highest so the uncomfortable feeling was also highest. The result of correlation analysis of green characteristics and the weather elements shows that GVZ and insolation, temperature has negative relationship, so it is considered that the higher the GVZ is, the solar radiation and the temperature are decreased.