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        검색결과 557

        423.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        In the present study we examine physical characteristics of a thin and rigid magnetic flux tube with a steady flow inside, which is embedded vertically upward in the solar atmosphere. We found from this study that (1) The downward material flow gives rise to a dominant heating in the flux tube which works with the conductive heating in the same direction. However, the upflow flow creates a dominant cooling which works against the conductive heating, resulting in a steeper temperature gradient with a shallower transition region. (2) Since the thickness of the transition region determines the material content in the transition region, a broader transition region of the downflow tube produces a larger differential measure.
        424.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We have mapped 17 deg2 region toward Galactic anticenter in 12CO J = 1 - 0 using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory (TRAO). The region mapped in this paper is the first target of the Galactic AntiCenter CO Survey Project (GACCOS) and was selected comparing with IRAS Sky Survey Atlas (ISSA) images at 100 μm. Molecular emission of the target area is found to be very extended and is well matching with the FIR emission boundary. There are several pieces of clouds, and as some of spectra show several peaks, there seem to be several clouds overlapped in some directions. The Velocity of Local Standard of Rest (VLSR) of the CO emission of the mapped region ranges from -20 to +10 km/s. It is also found that the two cloudlets located around I = 180° have VLSR = -20 km/s, which is very abnormal. The peak antenna temperature of 13 K arises near the H II Region S241.
        425.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We present the results of an rocket-borne observation of far-infrared [CII] line at 157.7 μm from the diffuse inter-stellar medium in the Ursa Major. We also introduce a part of results on the [CII] emission recently obtained by the IRTS, a liquid-helium cooled 15cm telescope onboard the Space Flyer Unit. From the rocket-borne observation we obtained the cooling rate of the diffuse HI gas due to the [CII] line emission, which is 1.3±0.2 × 10-26 ergss-1 H-1atom. We also observed appreciable [CII] emission from the molecular clouds, with average CII/CO intensity ratio of 420. The IRTS observation provided the [CII] line emission distribution over large area of the sky along great circles crossing the Galactic plane at I = 50° and I = 230°. We found two components in their intensity distributions, one concentrates on the Galactic plane and the another extends over at least 20° in Galactic latitude. We ascribe one component to the emission from the Galactic disk, and the another one to the emission from the local interstellar gas. The [CII] cooling rate of the latter component is 5.6 ± 2.2 ×10.
        426.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        The solar neighbourhood is the starting point for studies of the structure and evolution of the Galactic disk. Yet, our knowledge of the relative frequencies, distances, ages, chemical abundances, velocities, and birthplaces of the nearby stars is severely incomplete. We have determined complete, homogeneous, and precise such data for a kinematically unbiased sample of ~12,000 local F and G dwarf stars and describe a first, significant result from it.
        427.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We review observational evidence bearing on the formation of a prototypical large spiral galaxy, the Milky Way. New ground- and space-based studies of globular star clusters and dwarf spheroidal galaxies provide a wealth of information to constrain theories of galaxy formation. It appears likely that the Milky Way formed by an combination of rapid, dissipative collapse and mergers, but the relative contributions of these two mechanisms remain controversial. New evidence, however, indicates that initial star and star cluster formation occurred simultaneously over a volume that presently extends to twice the distance of the Magellanic Clouds.
        4,000원
        428.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        Based on the database of 128 disk galaxies (66 SO, 62 S and Irr) mailnly compiled from Kent and Gunn (1982) and Doi et a1.(1995) which is complete down to m < 15.6 mag within a radius of 3°, the orientation of spin vectors of disk galaxies of the Coma cluster has been analyzed. The results confirm the morphological dependence of the orientation of disk galaxies found from the analsis of the Virgo cluster. Common features of orientation of disk galaxies of both clusters are outlined.
        431.
        1996.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        실내에서 담배거세미나방의 영기별 약제감수성을 조사한 결과 시험된 약제 모두 유충의 영기가 높아질수록 약제감수성은 낮았다. Chlorpyrifors-methyl과 chlorpyrifos의 독성은 3령부터, etofenprox+PAP와 deltamethrin은 2령부터 현저히 떨어졌다. 포트시험결과 deltamethrin을 제외한 4약제 모두 90% 이상의 방제가를 보여 담배거세미나방의 방제에 유용하게 사용될 수 있을 것으로 생각된다. 하지만 야외에서 담배거세미나방은 전 영기가 혼재되어 있고 영기별 약제감수성이 다르기 때문에 적절한 약제선택은 물론 유충 발생초기에 약제를 살포하는 것이 중요하다.
        4,000원
        434.
        1995.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recent discovery of an Io-related feature in Jupiter's auroral regions prompted us to search for an or multiplet at 1304Å in IUE aurora spectra. In three independent IUE spectra taken on January 18, 1981, we found an emission structure at 1304Å , with a signal-to-noise of about three. If the structure is due to the OI emission, then it is a direct evidence of oxygen ion precipitation, which may originate from Io and Io torus. The emission rates of the H2 H2 band systems and the or multiplet are about 50 kR and 150 R, respectively. We have constructed high resolution model spectra with the estimated emission rates of H2 H2 , OI and SI for the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope. The model spectra clearly show the or and SI mulitplets separated from crowded H2 H2 Lyman and Werner band lines, and therefore it is promising to detect the OI and SI multiplets with the GHRS. Given the possibility that the lo-related feature may be caused by ion precipitations from the Io flux tube, it is likely that the OI emission may be detected in the footprint area of the IO flux tube.
        4,000원