간행물
한국지구과학회지 KCI 등재 The Journal of The Korean Earth Science Society
- 발행기관 한국지구과학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1225-6692 (Print)2287-4518 (Online)
- 수록기간 1979 ~ 2024
- 주제분류 자연과학 > 지구과학 자연과학 분류의 다른 간행물
- 십진분류KDC 450DDC 550
권호리스트/논문검색
제7권 제1호 (1986년 6월) 7건
1.
1986.06
구독 인증기관 무료, 개인회원 유료
Sixty-eight open clusters have been sampled in proportion to the age fraction of the number distribution of open clusters in Galaxy in order to find out the aging effect in number density distribution of member stars of the open clusters. The Ring method can be used to establish the number density distribution around the central regions of the open clusters. Their number density distributions have been classified to several types according to their shapes. They have been arranged to a serial distribution of A to F in age.
4,000원
2.
1986.06
구독 인증기관 무료, 개인회원 유료
In the Yeongil area, the Tertiary lacustrine sediments belonging to the Janggi or Beomgogri Group are widely distributed, and they are intimately associated with the Tertiary volcanics and the Yeongil basalt in space and time. The Tertiary strata are mainly composed of pyroclastic deposits resulting from the subvolcanic eruption of intermittently ascending magma prior to the emplacement of the volcanics. The Nuldaeri volcanics belong to calc-alkali rock series in chemical composition, which show basaltandesite-dacite-rhyolite series. It is composed chiefly of voluminous dacite, which is divided into massive dacite and brecciated dacite in the texture and andesite, and accompanied with less abundant rhyolite. Basalt also occurs in small amount by the xenolith in the basaltic tuff. The main constituent minerals of these rocks are plagioclase, pyroxene, hornblend, biotite, and minor constituent minerals are magnetite, apatite and calcite. Chemical analyses of 14 volcanic rocks are given. The analyses are plotted in several variation diagrams; SiO₂-total alkali, SiO₂-oxide, AFM, FeO^*/Mgo-FeO^* and FeO^*/Mgo-SiO₂ diagram. The Nuldaeri volcanics belong to the subalkali rock series, A-F-M diagram shows a gradual trend toward alkali enrichment. The several evidences support the view that the Nuldaeri volcanics were derived from basaltic parental magma by process of crystallization differentiation.
4,000원
3.
1986.06
구독 인증기관 무료, 개인회원 유료
The computation of the undulation of the Moho discontinuity from gravity data has frequently been carried out by the application of the Fourier series and the Sinc function (sin x/x), However, no serious effort has been attempted to examine the suitability of data and the adaptability of implicit assumptions required in such methods. This paper deals with model studies for comparison of the Fourier series and Sinc function methods, and examinations of several criteria for obtaining meaningful results. Also, an inversion method based on mass plane concept has been devised to complement the weakness of the above two methods. This method has been appeared as an effective scheme for increasing depth computation points so that a more detailed undulation is obtained.
4,900원
4.
1986.06
구독 인증기관 무료, 개인회원 유료
A finite difference numerical model for tidal current for the region of wide open boundaries has been established. A special attention is paid to developing a new method to treat open boundary condition, Along the open boundaries, it is supposed to know the sea surface elevations. Therefore, it is possible to apply the continuity equation to find boundary velocity at each boundary point using the elevations and the interior velocities adjacent to the boundary point at every time step. After the velocities along the boundaries are calculated, they are used to find a solution for the interior region. At the next time step new boundary velocities are calculated using the solution. The whole process is repeated until the solution converses to the tolerable range. This model with 4 tidal components, N₂, S₂, K₁, and O₁, is applied to the sea off Kunsan, the west coast of Korea. The model converses after about a-day's run when the time difference at each step is 30 seconds. The velocities produced by the model with the developed boundary method show no instabilities in the domain of computation. In comparision with the observed velocities, the computed ones show a fair agreement.
4,200원
5.
1986.06
구독 인증기관 무료, 개인회원 유료
Bipolar molecular outflows have been observed and analyzed with molecular emission lines, Especially, ^(12)CO(J=1→0) has been used to figure out their kinematic structures instead of H₂ molecule owing to the H₂ observational difficulties. Since 1980' s, the wing portions of the observed line profiles of ^(12)CO toward the molecular clouds, which might have been observed as star-formation regions, have been important to explain the dynamical behavior of the molecular clouds, that is, the interaction of the wind type flow from a central IR source with the surrounding molecular clouds. The interaction surely develops the bipolar shaped outflow pattern due to the rotational molecular disk surrounding the central source. The molecular disks have been observed with CS, SO₄ molceular emission lines that are useful to reveal the high density regions in the molecular cloud complexes. IR observations have also found out the existence of the buried central sources and their luminosities. The reversely developed wing portions in opposite regions with respect to the central IR source distinctively show the bipolar-shaped radio lobes, meaning the opposite directed outflows with an average velosity of∼25 ㎞ sec^(-1). Their average size and dynamical time scale are ∼1pc and ∼2×10⁴ yrs respectively. The mass involved in the outflow can be estimated with the aid of ^(13)CO obvervation toward the bipolar outflow regions. These regions have often optical or radio jets inside, sometimes, being related to Herbig-Haro objects and the shocked regions at their ends. The energetics and moments related to the outflows show that the radiative momentum of the central source can not produce the flows unless the radiation interact with the environmental gas many times, and also that they seem to be independent of the dynamical behaviors of the outflow, i.e., the size and the velocity themselves, and only to be dependent on the mass involved the outflows. The occurrance rate of the bipolar molecular outflow is estimated to be∼4×10⁴yr^(-4) kpc^(-1) with their number detected within the 1 kpc solar circle. This shows that the phenomena of the bipolar outflows can be produced in all kinds of spectral type stars, which might approach to the main-sequence in HR diagram. Many theories have been suggested to explain both the dynamics and the energetics of the outflows, being still insufficient. We expect that the molecular line observation with a high angular resolution and the developed theories should figure out the details of the outflows near future.
4,000원
6.
1986.06
구독 인증기관 무료, 개인회원 유료
3,000원
7.
1986.06
구독 인증기관 무료, 개인회원 유료
4,000원
