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        검색결과 28

        21.
        2010.04 구독 인증기관·개인회원 무료
        22.
        2009.10 구독 인증기관·개인회원 무료
        23.
        2009.10 구독 인증기관·개인회원 무료
        This study was performed to compare the host preference, survivorship and feeding behavior using EPG against ggot-mae-mi, Lycorma delicatula against seven plants such as Ailanthus altissima, Vitis vinifera, Malus pumila, Pyrus calleryana, Hibiscus syriacus, and Pinus densiflora. In host preference. L. delicatula was most preferred the Ailanthus altissima, Vitis vinifera and was not preferred the other plants. Survival rate of 3rd Nymph was recorded from Ailanthus altissima, Vitis vinifera as 15.0, and 15.4 days, respectively, it showed longest period. However, Malus pumila, Pyrus calleryana, Hibiscus syriacus, were survived within 6 days and Pinus densiflora was within 5 days. Moreover, L. delicatula was survived within 2 days to the three kinds of fruits. Ecdysis rate from 3rd to 4th nymph also high from Ailanthus altissima, Vitis vinifera as 63.3, 63.0 % and the order was followed as Malus pumila(17.7%) > Pyrus calleryana(9.3%) > Hibiscus syriacus(7.8%) > Pinus densiflora(5.9%). Especially, ecdysis rate was recorded 0% to the three kinds of fruits. Feeding behavior was analyzed using EPG and compared the differences their waveform from seven kinds of plants and three kinds of fruits. Non-probing time was short in host plants, reversely, Phloem-feeding time was recorded longer in Ailanthus altissima, Vitis vinifera as 45.7 and 13.7 min, respectively. And other plants and fruits were not showed feeding behavior.
        25.
        2007.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The original environment of the solar system can be inferred by studying the oxygen isotope ratios in the Sun as well as in primitive meteorites and comets. The oxygen isotopic fractionation measured in primitive meteorites is mass-independent, which can be explained by the isotopic-selective photodissociation of CO. The isotopic-selective photodissociation model in a collapsing cloud by Lee et al. (2007) imply the birth of the Sun in a stellar cluster with an enhanced radiation field, which is consistent with the inferred presence of 60Fe.
        4,000원
        26.
        2007.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A new type of object called "Very Low Luminosity Objects (VeLLOs)" has been discovered by the Spitzer Space Telescope. VeLLOs might be substellar objects forming by accretion. However, some VeLLOs are associated with strong outflows, indicating the previous existence of massive accretion. The thermal history, which significantly affects the chemistry, between substellar objects with a continuous low accretion rate and objects in a quiescent phase after massive accretion (outburst) must be greatly different. In this study, the chemical evolution has been calculated in an episodic accretion model to show that CO and N2H+ have a relation different from starless cores or Class 0/I objects. Furthermore, the CO2 ice feature at 15.2μm will be a good tracer of the thermal process in VeLLOs.
        4,000원
        28.
        1999.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have carried out high-resolution observations along one-dimensional cuts through the three Galactic super-shells GS 064-01-97, GS 090-28-17, and GS 174+02-64 in the HI 21 cm and CO J=l-0 lines. By comparing the HI data with IRAS data, we have derived the distributions of the I100 and T100 excesses, which are, respectively, the 100 μm intensity and 100 μm optical depth in excess of what would be expected from HI emission. We have found that both the I100 and T100 excesses have good correlations with the CO integrated intensity W co in all three supershells. But the I100 excess appears to underestimate H2 column density N(H2) by factors of 1.5-3.8. This factor is the ratio of atomic to molecular infrared emissivities, and we show that it can be roughly determined from the HI and IRAS data. By comparing the T100 excess with Wco, we derive the conversion factor X ≡ N (H2) /Wco ≃ 0.26 - 0.66 in the three supershells. In GS 090- 28-17, which is a very diffuse shell, our result suggests that the region with N(H2) ≾ 3 × 10 20 cm-2 does not have observable CO emission, which appears to be consistent with previous results indicating that diffuse molecular gas is not observable in CO. Our results show that the molecular gas has a 60/100 μm color temperature Td lower than the atomic gas. The low value of Td might be due either to the low equilibrium temperature or to the lower abundance of small grains, or a combination of both.
        4,500원
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