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        검색결과 210

        102.
        1997.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A small ultraviolet telescope which can be established on a satellite of the Korean small satellite (KITSAT) series is proposed with a concept design. Possible scientific objectives are identified, and the basic structure and characteristics of the telescope are described. In order to overcome limitation of pointing and stabilization accuracy of the KITSAT, a system of secondary stabilization is designed at the focal plane, where both star-tracking CCD and science detector share a 1.2deg field of view. Star tracking information is fed to three-axis drivers that move the platform on which the star-tracking CCD and science detector are installed. The proposed stabilization system is light and efficient, in comparison with a standard system of stabilization that basically moves the whole telescope or satellite. With a good intensified CCD and second stabilization system, the telescope will achieve a limiting magnitude of 21 at 1600 angstrom, which is sufficient for observing a variety of celestial objects, such as hot stars, nebulae, galaxies with UV excess, and quasars.
        4,000원
        103.
        1997.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Observational trends of the Jovian UV aurora, obtained from the Goddard High Resolution Spectrograph(GHRS) on board the Hubble Space Telescope(HST), are explained by a simple two component model. The model consists of cool and warm components with temperatures of about 400 and 1000K, and with methane absorptions corresponding to column densities of 6-9e16/cm2 and no methane absorption, respectively. Three trends that (1) brighter UV spectra have lower temperatures, and (2) spectra with stronger methane absorption show lower temperatures, and (3) spectra with stronger methane absorption seem to be brighter, are accounted by combinations of two components with various filling factors and intensity ratios. The model implies that precipitating particles responsibie for the cool component have higher individual energy and stronger energy flux than those for the warm component. Estimation of GHRS aperture location on UV auroral images taken by the Wide Field Planetary Camera 2(WFPC2) suggests that the cool component may correspond to emission along the oval, and the warm component to diffuse features of UV emission. Preliminary comparison of images by the WFPC2 and those by H3+ 4 micrometer ground-based observations implies that the warm component causes both weak diffuse features of UV emission and bright H3+ emission in an area at lambda III - 150 deg. inside the northern oval.
        4,000원
        104.
        1997.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        5,400원
        105.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the 1.5 μm NH3 band, the 2.3 μm CH4 band, the 2.12 μm H2 S(0) pressure-induced absorption, and the continua at 1.58 μm and 2.0 μm (short K-band). All images except those with the 1.58 μm continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about 45° S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric CH4, NH3 or H2. The impact sites observed with the 2.3 μm filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and 2.12 μm filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about 1%. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.
        4,000원
        106.
        1995.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Adult diapause in insects is characterized by suppression of reproductive development. It is induced by environmental cues such as photoperiod, temperature, food availability, and other conditions Diapause-inducing environment is recognized and analyzed by the brain of the insects. The interpreted information is conveyed via endocrine system to target tissues such as ovaries, fat body, and other tissues. From this signal hierarchy of a brain-endocrine-target tissue axis, several factors are involved to express a diapause trait in a quantitative mode, even though the insects show a binomial phenotye between being in diapause or not. Recent works estimated that the number of the factors is relatively small by a series of crossing trials between high and low diapause lines. Heritability of the diapause is quite high (ca. 70%) in some species. Epistasis, sex-linkage, pleiotropism, and other nongenetic components also affect diapause inheritance. Most physiological studies have been focused on control mechanisms of the juvenile hormone (JH) synthesis in corpora allata (CA) because JH level in hemolymph of teneral adults is critical to decide a later developmental mode. Allatostatin, an antagonizer of JH synthesis, has been believed to be a potent brain message to CA for adult diapause induction.
        4,500원
        107.
        1993.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 동특성추정법 (system identification) 을 이용한 교량구조의 손상정도를 평가하는 방법이 제 시되었다. 손상된 구조물의 비선형 동적거동은 휩모우멘트와 곡률반경의 시간이력 관계로써 표시하였으며, 구조물의 성질을 나타내는 특성계수는 실측자료를 이용한 동특성추정법을 사용하여 추정하였다. 또한, 구조 물의 성질의 다양성과 응답의 불확실성을 고려하여 손상은 확률변수로 나타내었으며, 예제해석으로는 곡선교 의 손상도추정이 수행되었다.
        4,000원
        108.
        1978.12 구독 인증기관·개인회원 무료
        109.
        1971.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험은 우리나라에서 발생하는 푸른곰팡이병균의 종의 빈도와 발병환경 및 방제법을 구명코져 실시하였다. 시험결과 Trichoderma koningi, T. lignorum, T. glaucum과 미동정의 1종등 4종의 병원균이 분리되었고 이들의 빈도는 각각 와 이었다. 푸른곰팡이병균은 감자배양액, 왁스만배양액과 리차드배양액에서 생육이 잘 되었으며 중성-염기성배지에서는 생육이 불량한 반면 산성에서 생육이 왕성하였으며 최적산도는 pH4였다. 양송이 수확기간 중 재배사내의 온도는 내외 일 때 본명의 발생이 적었고 수량이 많으며 이상에서는 본병의 발생이 격심하였다. 푸른곰팡이병균은 복토흙 소독시 에서 60분, 혹은 에서 30분간 열처리하므로서 완전히 사멸하였고 퇴비 후발효 과정에서도 사멸되었다.
        4,000원
        110.
        2019.02 KCI 등재 서비스 종료(열람 제한)
        본 연구는 하상재료의 종류와 유속에 따른 세굴변화에 대한 연구를 진행하였고, 유속, 구성방법 및 재료와 세굴에 대한 상관관계를 정의하여 호안 및 제방의 운용성을 검토하고자 실험을 통한 연구를 진행하였다. 본 연구의 실험에 사용된 재료는 제방에 사용되고 있는 재료로 모래, 황토를 이용 하였다. 실험실규모 고속수로에서 다양한 계측장비들을 이용하여 유속의 변화에 따른 재료의 세굴을 측정하였다. 이를 통해 세굴 전·후의 재료변 화를 수치적으로 분석하였다. 고유속흐름에서 하상재료에 따라 세굴의 정도를 비교·평가하여 안정성에 대한 연구도 진행하였다. 실험 결과 모래의 경우 응집력이 매우 약하여 1.0 m/s 이하에서도 40% 이상의 재료가 유실이 되고 황토의 경우 모래보다 유속이 빠른 2 m/s 이상에서도 6% 이하 의 재료가 유실이 되었다. 재료가 유실된 이유중 하나는 강한 응집력으로 건조균열이 발생하여 세굴에 취약한 결과를 보였다. 본 연구에서는 이러한 건조균열의 발생부터 재료가 유실되는 현상을 제거하는 방법부터 재료에 대한 구성과 유실정도를 평가 하였다.
        111.
        2018.10 KCI 등재 서비스 종료(열람 제한)
        본 연구의 목적은 금강유역(9,645.5 km2)을 대상으로 극한 기후변화 사상에 따른 수문 및 유황의 변동을 평가하는 것이다. 본 연구에서는 객관적인 극한 기후변화 사상을 평가하기 위해 강우관련 극한지수(STARDEX)를 적용하고, GCM 10개의 RCP 8.5 기후변화 시나리오에 대해 4개의 평 가기간별(Historical: 1975~2005, 2020s: 2011~2040, 2050s: 2041~2070, 2080s: 2071~2100)로 분석하였다. 분석 결과 5개의 습윤 (CESM1-BGC, HadGEM2-ES), 중간(MPI-ESM-MR) 건조(INM-CM4, FGOALS-s2) 극한 기후변화 사상 시나리오를 선정하여 SWAT 모형에 적용하였다. 2080s 기간에서 중간시나리오 대비 2080s의 증발산은 -3.2~+3.1 mm로 변화하였고, 2080s의 총 유출량은 +5.5~+128.4 m3/s 변화하였다. 건조한 시나리오의 경우 2020s 중간시나리오대비 큰 변화를 보였다. 건조한 시나리오에서의 2020s의 증발산량은 -16.8~-13.3 mm 의 변화를 보였고, 총 유출량은 -264.0~132.3 m3/s의 변화를 보였다. 유황 변동의 경우, 2080s 기간의 습윤한 시나리오에서 CFR은 +4.2~+10.5, 2020s 기간의 건조한 시나리오에서는 +1.7~2.6으로 변화 하였다. 극한 기후변화 시나리오를 적용한 금강유역의 수문인자의 변화에 따라 유황분 석을 실시한 결과, INM-CM4는 극한 건조상태를 나타내기에 적절한 시나리오로 나타났고 FGOALS-s2는 유황변동이 큰 가뭄 상태 분석에 적절한 시나리오로 나타났다. HadGEM2-ES는 유황변동이 작게 나타났기 때문에 최대유량 분석 시 활용 가능한 시나리오로 평가되었고, CESM1-BGC 의 경우 유황변동이 큰 것으로 나타나 극한 홍수 분석 시 적용할 수 있는 시나리오로 평가되었다.
        112.
        2018.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Gold kiwifruit was fermented with Lactobacillus plantarum CK10 derived from kimchi and the fermented products were extracted with ethanol at various fermentation time-points The bacterial cellular density, total titratable acidity, total polyphenol content (TPC), and total flavonoid content (TFC) increased during fermentation, while pH values and total soluble solids decreased. Levels of TPC and TFC were highest after five days, at 1.21±0.13 mg GAE/g dry weight and 0.36±0.04 mg RE/g dry weight, respectively. The antioxidant activities of the fermented gold kiwifruit were analyzed using Fe2+ chelating activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH)-, and 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid) (ABTS)- radical scavenging activities, and superoxide dismutase (SOD)-like activity. The Fe2+ chelating activity of gold kiwifruit (125-500 μg/mL) peaked after five days of fermentation at 38.40-78.47%. The DPPH radical- scavenging activity and SOD-like activity were somewhat higher after seven days of fermentation (36.01-86.81% and 54.79-93.83% at 2.5-10.0 mg/mL concentration of samples, respectively). On the other hand, the ABTS radical- scavenging activity of fermented gold kiwifruit was similar to that of the non-fermented form. The polyphenol and flavonoid contents were significantly correlated with the antioxidant activity. In conclusion, our results suggest that TPC, TFC, and antioxidant activity were increased after five and seven days of fermentation, respectively. Therefore, fermented gold kiwifruit with its increased antioxidant activity could be useful in the development of functional foods.
        113.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        Ascidian embryos have become an important model for embryological studies, offering a simple example for mechanisms of cytoplasmic components segregation. It is a well-known example that the asymmetric segregation of mitochondria into muscle lineage cells occurs during ascidian embryogenesis. However, it is still unclear which signaling pathway is involved in this process. To obtain molecular markers for studying mechanisms involved in the asymmetric distribution of mitochondria, we have produced monoclonal antibodies, Mito-1, Mito-2 and Mito-3, that specifically recognize mitochondriarich cytoplasm in cells of the ascidian Halocynthia roretzi embryos. These antibodies stained cytoplasm like reticular structure in epidermis cells, except for nuclei, at the early tailbud stage. Similar pattern was observed in vital staining of mitochondria with DiOC2, a fluorescent probe of mitochondria. Immunostaining with these antibodies showed that mitochondria are evenly distributed in the animal hemisphere blastomeres at cleavage stages, whereas not in the vegetal hemisphere blastomeres. Mitochondria were transferred to the presumptive muscle and nerve cord lineage cells of the marginal zone in the vegetal hemisphere more than to the presumptive mesenchyme, notochord and endoderm lineage of the central zone. Therefore, it is suggested that these antibodies will be useful markers for studying mechanisms involved in the polarized distribution of mitochondria during ascidian embryogenesis.
        114.
        2017.05 서비스 종료(열람 제한)
        Background : The practice of keeping the medicinal herbs at room temperature causes many problems, but due to lack of sufficient field research and study, it is difficult to improve related regulations and safety management. Methods and Results : The Cnidium Rhizome and Angelica gigas Root were inoculated with Lasioderma serricorne F. and incubated at 28℃ for 2.5 months and 5 months. After five months, the number of Lasioderma serricorne F. in Cnidium Rhizome increased from 30 to 1,429 (about 47 times). In the same period, the number of insects in Angelica gigas Root increased from 30 to 663 (about 22 times). Due to the rapid increase in pest population, hygiene deteriorated, changes in the active ingredient and appearance quality of the herbal medicines, which greatly damaged the value of the herbal medicine. Conclusions : These results show that current regulation requiring only sealing and not specifying the storage temperature do not guarantee quality safety. Therefore, it is necessary to establish appropriate preservation standards and improve management regulations in order to preserve safety.
        115.
        2017.05 서비스 종료(열람 제한)
        Background : The hyphal growth of Poria cocos are known to grow well under medium temperature(25 - 28 ℃) and acidic(pH 4.0 - 5.0) conditions. Also, it is known that a large difference in the yield of Poria cocos depending on the cultivation method and environment. Therefore, this research was carried out to secure stable yield of Poria cocos using plastic house and bed soil. Methods and Results : The inoculation time was in mid-April 2016 and the inoculation amount was 3/4 lb each in pine trees of 60 (L) × 10 (D) ㎝. The inoculated wood was buried directly in the bed by soil composition and growth characteristics investigated after cultivating in plastic house from April to September, 2016. The composition of the bed soil was 6 treatments using peatmoss, cocopeat and perlite. The combination ratio ranges of peatmoss, cocopeat and perlite were 0 to 80 %, 0 to 60 % and 20 to 60 %, respectively. We assumed that the combination ratio of peatmoss (organic material) 60 % : perlite(inorganic material) 40% is good for the growth of the Poria cocos. In this ratio, instead of peatmoss, the amount of cocopeat was replaced by 20, 40, and 60 %, respectively. The pH and EC range of bed soil was 4.8 - 5.6, 0.7 - 2.2 dS/m, respectively. pH and EC tended to be lower in treatments with only peat moss and perlite. On the other hand pH and EC tended to raise with increasing cocopeat content. Volumetric soil water content and soil temperature were in the range of 13 - 28 % and 20 - 29℃, respectively, during the period of July to September. Soil water content tended to be higher with increasing cocopeat and peatmoss content and soil temperature tended to be lower. The degree of initial hyphal development and sclerotia formation were good in all treatments compared to the control. However, the number of sclerotia was 6 times higher in the ② treatment than in the control. The size of sclerotia was also the best at 12 (L) × 8 (W) ㎝ in the ② treatment. Conclusion : As a result of cultivating Poria cocos in plastic house, growth characteristics were different according to composition of bed soil. The first reason for this result is that the difference of soil moisture content depending on organic matter content affected the soil temperature. Actually, the average soil water content and soil temperature of ① treatment (organic material 80% ) showed 24% and 22℃ respectively during July to September, and no sclerotia was formed. However, in the ② treatment(organic material 60%), the average soil moisture and soil temperature were 14% and 26℃ during July to September, respectively and sclerotia formation was good. Another reason is that the pH of the bed soil affects the formation of sclerotia. Overall, the degree of hyphal development was good in low pH treatments, but no significant difference was found between the pH and the formation of sclerotia.
        116.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to examine the effects of NaOCl, sucrose, and BA concentration as pretreatment solution on quality and vase life of cut flowers in Dendranthema grandiflorum ‘Jinba’. Flower diameter, fresh weight, and vase life in control and 0 mg・L -1 NaOCl treatments decreased, and the treatment with 100~200 mg・L -1 NaOCl was more effective in the quality and vase life. In pretreatment with 2.5% sucrose solution, flower diameter and fresh weight decreased and vase life was shortest due to the rapid leaf wilting. However, pretreatment with 0.1% sucrose solution increased the flower diameter and fresh weight, and showed the longest vase life. When more than 80 mg・L -1 BA was treated with pretreatment solution, flower diameter and fresh weight decreased, and vase life was shortened. With pretreatment of 20 mg・L -1 BA, the flower diameter was bigger than in the other treatments, but it was no effect on fresh weight and vase life. Therefore, it was suggested that pretreatment solution mixed with 200 mg・L -1 NaOCl, 0.1% sucrose, and 20 mg・L -1 BA was the most effective for the quality and vase life of cut flowers in standard chrysanthemum ‘Jinba’.
        117.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to find a rapid determination of the hot air stress in maize (Zea mays L.) leaves using a portable chlorophyll fluorescence imaging instrument. To assess the photosynthetic activity of maize leaves, an imaging analysis of the photochemical responses of maize was performed with chlorophyll fluorescence camera. The observed chlorophyll imaging photos were numerically transformed to the photochemical parameters on the basis of chlorophyll a fluorescence. Chlorophyll a fluorescence imaging (CFI) method showed that a rapid decrease in maximum fluorescence intensity (Fm) of leaf occurred under hot air stress. Although no change was observed in the maximum quantum yield (Fv/Fm) of the hot air stressed maize leaves, the other photochemical parameters such as maximum fluorescence intensity (Fm) and Maximum fluorescence value (Fp) were relatively lowered after hot air stress. In hot air stressed maize leaves, an increase was observed in the nonphotoquenching (NPQ) and decrease in the effective quantum yield of photochemical energy conversion in photosystem II (Φ PSII). Thus, NPQ and ΦPSII were available to be determined non-destructively in maize leaves under hot air stress. Our results clearly indicated that the hot air could be a source of stress in maize leaves. Thus, the CFI analysis along with its related parameters can be used as a rapid indicating technique for the determining hot air stress in plants.
        118.
        2016.09 KCI 등재 서비스 종료(열람 제한)
        The wheat-rye translocations are world widely used in wheat breeding. Among the various forms of wheat-rye translocation, the 1RS (short arm of rye chromosome 1) translocations are the most widely used because of the valuable genes (e.g. biotic / abiotic resistance genes) introduced from rye. We have developed a new wheat-rye cultivar ‘TRANS’ which have freezing resistance and high yield in this study. ‘TRANS’ is a new wheat-rye translocation cultivar developed by crossing between common wheat ‘Keumkangmil’ and ‘951188-G3-G1’, a 1AL.1RS translocation derived from ‘Fleming’ with the aim of high yield and resistant genes to various unfavorable environments carried by 1RS. ‘TRNAS’ have clearly different genetic and agronomic traits to the control cultivar ‘Keumkangmil’. The heading date and maturity of ‘TRANS’ are later than that of ‘Keumkangmil’. ‘TRANS’ has 1023 spike number per square meters and grain yield of 541 kg/10a, which are higher than ‘Keumkangmil’ (904 spike number/m2 and 504 kg/10a yield). ‘TRANS’ showed winter hardiness and powdery mildew resistance in artificial infection test and field evaluation. ‘TRANS’ gives lower flour yield than ‘Keumkangmil’ but ash and protein content were similar to that of ‘Keumkangmil’. The color of flour and noodle dough of ‘TRANS’ were darker than ‘Keumkangmil’. Quality parameters related to milling, flour quality, noodle dough and end-use quality of ‘TRANS’ indicates that ‘TRANS’ is soft wheat suitable for noodle making. ‘TRANS’ can be cultivated in entire part of Korea. Registration Grant No.: 4695
        119.
        2015.09 서비스 종료(열람 제한)
        In animal development, the mechanisms by which localized factors and organelles in egg cytoplasm were exactly distributed into each daughter cell are essential for formation of various cell types. During ascidian Halocynthia roretzi embryogenesis, ooplasmic mitochondria were mainly segregated into muscle and neural precursor cells. At the 32-cell stage, localized mitochondria in the B6.2 blastomeres were preferentially distributed into the B7.4 muscle precursors compared with the B7.3 mesenchyme/ notochord precursors. When the B6.2 blastomeres were isolated from the early 32-cell stage embryos and then allowed to divide 2 times of cell division, the resultant partial embryos showed symmetric distribution of mitochondria, and the partial embryos were composed of equal size cells. In normal development, cell fates of the B7.3 blastomere were correlated with the unequal cleavage of B6.2 lineage cells that normally occurs in the next two-cell division stages to produce a large B8.5 mesenchyme and a small B8.6 notochord cell. Mitochondria are distributed asymmetrically in both cells. When embryos were treated with FGF receptor inhibitor SU5402 and MEK inhibitor U0126 between the 32-cell and the early 64-cell stages, the resultant embryos showed equal cleavage pattern and symmetric distribution of mitochondria in daughter cells of the B6.2 blastomeres. However, blocking of Nodal and Notch signaling did not affect the cell division pattern and mitochondrial distribution in the B6.2 lineage blastomeres between the 32-cell and 110-cell stages. Therefore, it is likely that FGF/MEK signaling is involved in asymmetric distribution of mitochondria and unequal cleavage of the B6.2 lineage blastomeres in ascidian embryo.
        120.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        Studies in Modern Grammar 70, 107-127. It is known that VP-ellipsis and VP-anaphora phenomena are typologically dependent. The goals of this paper is to offer a unified algorithm for English VP-ellipsis and Korean VP-anaphora, and show how the suggested resolution algorithm, adopted from Jager (2010), can account for these two in a uniform way.