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        검색결과 274

        221.
        1997.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We examine the corecollapse times of isolated, two-mass-component star clusters using Fokker-Planck models. With initial condition of Plummer models, we find that the corecollapse times of clusters with M1/M2 >> 1 are well correlated with (N1/N2)^0.5 (m1/m2)^2 Trh, where (M1/M2) and (m1/m2) are the light to heavy component total and individual mass ratios, respectively, N1/N2 is the number ratio, and Trh is the initial half-mass relaxation time scale. We also find two-component cluster parameters that best match multi-component (thus more realistic) clusters with power-law mass functions.
        4,000원
        225.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We have mapped 1 deg2 region toward a high latitude HII region S73 (l, b) = (37°.69, 44°.55) and associated molecular cloud in 12CO J = 1 - 0, and 13CO J = 1 - 0, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. A high resolution autocorrelator is used to resolve extremely narrow CO linewidths (FWHP < 1 km/s) of the molecular cloud. Though the linewidths are very narrow, it is found that there is systematic velocity gradient in the molecular gas associated with the H II region. Both of 12CO and 13CO averaged spectra are non-gaussian, and there are obvious blue wings in the spectra. It is remarkable that the linewidths at the blueshifted region are broader than those of the rest of the cloud. The CO emission does match well with the dust emission.
        228.
        1994.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have constructed a 3-dim hydrodynamics code called BTSPH. The fluid dynamics part of the code is based on the smoothed particle hydrodynamics (SPH), and for its Poisson solver the binary tree (BT) scheme is employed. We let the smoothing length in the SPH algorithm vary with space and time, so that resolution of the calculation is considerably enhanced over the version of SPH with fixed smoothing length. The binary tree scheme calculates the gravitational force at a point by collecting the monopole forces from neighboring particles and the multipole forces from aggregates of distant particles. The BTSPH is free from geometric constraints, does not rely on grids, and needs arrays of moderate size. With the code we have run the following set of test calculations: one-dim shock tube, adiabatic collapse of an isothermal cloud, small oscillation of an equilibrium polytrope of index 3/2, and tidal encounter of the polytrope and a point mass perturber. Results of the tests confirmed the code performance.
        5,100원
        232.
        1985.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼멸구에 대(對)한 벼품종간(品種間)의 피해(被害)와 수량(收量)을 조사(調査)하였다. 1983 년(年) 전남(全南) 해남(海南)에서 29개(個) 벼품종(品種)을 살충제무산포구(殺蟲劑無散布區), 살충(殺蟲) 및 살충제무산포구(殺蟲劑無散布區), 살균제무산포(殺菌劑無散布) 두어 이앙(移秧)하고 충밀도(蟲密度), 벼고사시기(枯死時期), 수량(收量)을 조사(調査)하였다. 삼강(三剛)벼, 가야(伽倻)벼, 한강(漢江)찰벼, 청청(靑靑)벼는 극히 낮은 밀도(密度)와 피해(被害)가 없었고 밀양(密陽) 30호(號)와 원풍(圓豊)벼는 중간정도(中間程度)의 밀도(密度)와 피해(被害)를 보였고 그 이외(以外) 품종(品種)은 높의 밀도(密度)와 고사현상(枯死現狀)을 나타냈다. 살충제무산포(殺蟲劑無散布)에 의한 수량(收量) 감수효과(減收效果)가 적었던 품종(品種)은 가야(伽倻)(12%), 삼강(三剛)벼(29%), 한강(漢江)찰벼(35%)였고 감수효과(減收效果)가 컷던 품종(品種)은 복광(福光)벼(260%), 팔금(八錦)(223%), 송전(松前)벼(200%), 관악(冠岳)벼(200%)였다.
        4,000원
        233.
        2021.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The auroral observation has been started at Jang Bogo Station (JBS), Antarctica by using a visible All-sky camera (v-ASC) in 2018 to routinely monitor the aurora in association with the simultaneous observations of the ionosphere, thermosphere and magnetosphere at the station. In this article, the auroral observations are introduced with the analysis procedure to recognize the aurora from the v-ASC image data and to compute the auroral occurrences and the initial results on their spatial and temporal distributions are presented. The auroral occurrences are mostly confined to the northern horizon in the evening sector and extend to the zenith from the northwest to cover almost the entire sky disk over JBS at around 08 MLT (magnetic local time; 03 LT) and then retract to the northeast in the morning sector. At near the magnetic local noon, the occurrences are horizontally distributed in the northern sky disk, which shows the auroral occurrences in the cusp region. The results of the auroral occurrences indicate that JBS is located most of the time in the polar cap near the poleward boundary of the auroral oval in the nightside and approaches closer to the oval in the morning sector. At around 08 MLT (03 LT), JBS is located within the auroral oval and then moves away from it, finally being located in the cusp region at the magnetic local noon, which indicates that the location of JBS turns out to be ideal to investigate the variabilities of the poleward boundary of the auroral oval from long-term observations of the auroral occurrences. The future plan for the ground auroral observations near JBS is presented.
        234.
        2015.07 서비스 종료(열람 제한)
        Many spectral imaging technologies are available to nondestructive means to assess plant status including abiotic and biotic stress conditions. In recent years, ARS has developed various sensing and instrumentation technologies for agricultural applications. These include hyperspectral imaging for visible/near-infrared (NIR) reflectance and fluorescence imaging, and multispectral laser-induced fluorescence imaging. Hyperspectral imagery is a fusion of imaging and traditional spectroscopy. We recently expanded the hyperspectral capabilities to include rapid macro-scale Raman chemical imaging. The current state of the art of imaging technologies and their potential applications for characterization of the plant status are presented.
        235.
        2014.02 서비스 종료(열람 제한)
        Urban stormwater runoff was considered to be more contaminated than the runoff from other land uses due to vehicle and human activities. Specifically, road runoff was commonly regarded as the primary pollutant (e.g. particulates and heavy metals) in the urban environment. Effectiveness of stormwater management strategies and treatment facilities in treating road runoff were highly based on the accuracy of the stormwater quantity and quality estimation. Although direct sampling of runoff during a storm event effectively quantifies the contaminant contributions in a specific area, it is expensive and time consuming. In order to efficiently design these treatment facilities based from the typical pollutant and hydrologic processes, the operation of modelling techniques were recommended. In this research, the physical characteristics of an existing tree box filter treating road runoff were adjusted using stormwater management model (SWMM) to determine the most suitable design configuration for better volume and pollutant reduction. The catchment area (CA), storage volume (SV) and surface area (SA) of the facility was increased or decreased by an increment of 25%. These changes were simulated by SWMM and would predict the influence of larger or smaller CA, SV or SA with respect to the facility performance. The hydrologic, hydraulic and water quality data used in the modelling were gathered from the 10 storm events monitored from July 2012 to July 2013. The total suspended solids were considered as the main target pollutants for this research however, the results will be correlated with the common heavy metal constituents present in the sampled runoff. Various design installations (e.g. series and parallel installation of tree box filter) were also modelled to accurately justify the obtained design configurations. Among the different configurations simulated, increasing the original values of the CA, SV and SA between 0.75% and twice the original value would result to better performance for the system. As for the installations being modelled, a centralized system would provide better volume and pollutant reduction than a divided system.
        237.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        An Intergenerational Horticultural Program in a rural community in Korea was tried out to enhance social interaction between elderly citizens and children, to promote the positive self-esteem of the elderly in a rural community, to change the attitude of children towards the elderly, and to create a rural community full of vitality. The clients were 20 elderly (60-80 years old) and 40 preschool children (6-7 years old). The activities in this program included seed of hope, round autumn garden, dish garden, in the vegetable patch, flower decoration for the Chuseok Festival, rainbow flower basket, heart card, fragrance of love, and a kimchi party. The results were a decrease in depression among the elderly from 44.0% to 33.7%. General satisfaction among the elderly was 100%. The desire to rejoin among the elderly was 100%. General satisfaction among the children was 100%. The desire to rejoin among the children was 93.5%.
        238.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        This study was performed to analyze the improvement of soil physical property and soil biota characteristics through cultivation of green manure crops for a one-year period before creation of a tea plantation as follows. The study revealed that the contents of available phosphate tended to decrease after sod-culture by green manure cultivation and open-pollination, when compared to the level before cultivation. The ratio soil porosity increased by approximately 30% when Crotalaria juncea and Sorghum bicolar L. Moench were cultivated, while the soil bacteria and fungi also increased. In a research on microfauna using a pit fall trap, the population number of the microfauna was 174 of 27 species in the plot of open-pollinated sod-culture and no organic matter application, and 268 of 26 species in the plot of Sorghum bicolar L. Moench. Consequently, the culturing tool of Crotalaria juncea recorded the highest level of species diversity at 2.5, the evenness index at 3.7 and richness at 4.6, with the lowest level of a dominance index. The ecological quotient of microfauna was 0.76 in the plot of Sorghum bicolar L. Moench, and 0.63 in the plot of Crotalaria juncea.
        239.
        2011.06 KCI 등재 서비스 종료(열람 제한)
        This paper details the maritime accidents that occurred in the Philippines from 1972 to 2010. Firstly, it describes the general maritime situation in the country. It was followed by the traffic and safety infrastructure and the prevailing weather in the archipelago. The third section deals with the accidents' statistics and their geographical locations which is further sub-divided into three regions. It is grouped according to 10-year period. This paper describes the actual maritime situations, the pertinent national regulations, the inter-agencies policies and their safety regimes. It illustrates the shipping environment in the country including the maritime aids and infrastructure and the on human element factors.
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