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        검색결과 141

        104.
        1998.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have observed the 10-9 transitions of HC3N and its 13C substitutes (H13CCCN,HC13CCN, and HCC13CN), and the vibration ally excited 12-11 (vr=1) HC3N transition toward the Sgr B2 molecular cloud. The observed HC3N emission shows an elongated shape around the Principal Cloud (~4.5 pc in R.A. × 7.4 pc in Decl.). The optically thin H13CCCN line peaks around the (N) core and we derive the total column density N(H13CCCN) = 4 ×10 13 cm-2 at this position. Toward the 2' N cloud which shows the peculiar chemistry, the HC3N lines show enhancements compared to the extended envelope. The shocks of the 2' N may have resulted in the enhancement of HC3N. The hot component of HC3N is strongly concentrated around the (N) core and its HPW is ~0.9 pc in diameter. We derive the lower limit of the abundance ratio N(HC3N)/N(H13CCCN) to be larger than 40 in most regions except the (M) and (N) cores. The fractionation processes of 13C at this region may not be as effective as previously reported.
        4,000원
        112.
        1993.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리나라에 발생하고 있는 벼멸구 생태형의 형태적 차이를 구명하고자 생태형 1, 2, 3의 단시형 암컷과 숫컷의 다리부분의 형태를 관찰하였다. 앞다리, 가운데 다리 그리고 뒷다리의 제3부절의 형태를 51개 부위에서 조사한 다음 통계학적 분석을 위하여 정준 판별 분석법을 도입하였다. 각 생태형간의 Mahalanobis distance는 숫컷의 경우 생태형 2와 3 사이에서 가장 짧았고, 암컷은 생태형 1과 2 사이에서 가장 길었다. Scatter plot diagram상에서 각 생태 형간 분리현상이 뚜렷하여 중심점이 각각 다르게 나타났고 각 생태형에 속하는 개체는 중심점 부근에 고르게 분포하였다. 각 생태형간의 Group membership 조사에서 암수 모두 각 생태형은 각각 동일한 생텨형을 분류되었다.
        4,000원
        117.
        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
        118.
        2015.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We have carried out photometric follow-up observations of bright transiting extrasolar planets using the CbNUOJ 0.6 m telescope. We have tested the possibility of obtaining high photometric precision by applying the telescope defocus technique, allowing the use of several hundred seconds in exposure time for a single measurement. We demonstrate that this technique is capable of obtaining a root-mean-square scatter of sub-millimagnitude order over several hours for a V ~10 host star, typical for transiting planets detected from ground-based survey facilities. We compared our results with transit observations from a telescope operated in in-focus mode. High photometric precision was obtained due to the collection of a larger amount of photons, resulting in a higher signal compared to other random and systematic noise sources. Accurate telescope tracking is likely to further contribute to lowering systematic noise by exposing the same pixels on the CCD. Furthermore, a longer exposure time helps reduce the effect of scintillation noise which otherwise has a significant effect for small-aperture telescopes operated in in-focus mode. Finally we present the results of modelling four light-curves in which a root-mean-square scatter of 0.70 to 2.3 milli-magnitudes was achieved.
        119.
        2015.02 서비스 종료(열람 제한)
        Recently, Low Impact Development (LID) technology has been developed and used to collect, infiltrate, filter and confine runoff in order to enhance the storm water quality and to preserve the natural water cycle. In this study, two technologies were employed in order to treat runoff from an impervious surface such as a paved road and a parking lot. The infiltration trench which was constructed to manage stormwater runoff from a paved road abates and temporarily holds stormwater runoff and removes sediments and attached pollutants within the sub-surface structure prior to infiltration into the subsoils. On the other hand, the tree box filter which incorporates trees and other gardening plants to regulate and treat runoff drains the stormwater from a parking lot. The infiltration trench and tree box filter represent only 1% of the catchment area that they drain. This research was conducted to evaluate the hydrologic and water quality effects of the infiltration trench and tree box filter after LID. Storm event monitoring was conducted for the infiltration trench from May 2009 to August 2014 with a total of 38 storm events and 24 storm events in the tree box filter from July 2010 to July 2014. Hydrologic (i.e., total rainfall, antecedent dry day (ADD), runoff volume, etc.) and water quality (i.e. particulates, nutrients, organics, and heavy metals) parameters were analyzed before and after LID. The major findings of this study are as follows: The runoff before LID was discharged directly to the sewers and could lead to local flooding of transport systems and pollution to receiving waters during intense storm events. But, after LID the runoff was partially reduced for atleast 50% on the two (2) urban landuses. Furthermore, the pollutant concentration before LID was observed to be at high concentrations. However, it was reduced to an approximate of 60% after LID. With the combined processes of infiltration, filtration, retention and evapotranspiration that were provided by the infiltration trench and tree box filter, the runoff was partially reduced and a significant decrease in pollutant concentration has been observed. The results and findings of this study will help facilitate the LID for further application.
        120.
        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.
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