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1968년 ~ 2023년까지 1,187 건의 한국천문학회지를 격월간 확인하실 수 있습니다.
- The Korean Astronomical Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-4614 (ISSN : 1225-4614)
1225-4614
- DB구축현황 : 1,187건 (DB Construction : 1,187 Articles)
총 게시글 1,187건
페이지 78/119
771
- SUNG EON-CHANG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.87-88
- 1996
- 원문 바로보기
772
- CHANG KYONG-AE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.1
- pp.1-8
- 1996
- 원문 바로보기
When we follow the lines of the trajectory of photons which intersect the circle, the circle may suffer some deformation as approaching to the observer. We consider an infinitesimal light bundle suffering gravitational bending. We examine the deformation of the deflected light bundle due to the gravitational lens. The size of the deformation is expressed in terms of the focal length of the gravitational lens.
773
- CHAKRABARTI SANDIP K.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.281-282
- 1996
- 원문 바로보기
774
- TOHMURA ICHIROH
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.333-335
- 1996
- 원문 바로보기
Here we report the results from spectroscopic observations of soloar active regions in the HeI 10830 <TEX>${\AA}$</TEX> line at the German Vacuum Tower Telescope(VTT) in Tenerife during the August 199:3 International EFR(Emerging Flux Region) Campaign. Four active regions in various stages of their evolution, i.e., NOAA7558, 7560, 7561, and 7562, were ovserved on 10 August 1993. From the observed HeI 10830 <TEX>${\AA}$</TEX> spectra in these active regions, spectroscopic quantities such as equivalent width(EW), doppler shift, doppler width, etc., were derived(see Figure l(a)) and the correlation between them were studied(see Figure l(b)). Our main results are as follows: (I)In NOAA7562, which is a young and evolving EFR, the EW is large, while it is small around a simple and roundish spot of NOAA7558. (2)In these active regions, redshift in the 10830 line is dominant when the EW is larger. (3)As the doppler width increases, the line tends to shift redward. (4)When the EW is smaller, it seems to exist another component which have dynamic characteristics different from the redshifting component. In NOAA7560 and NOAA7561, regions which have several small spots, the values of the EW are intermediate. Results (2) and (3) may suggest the possible existence of downflow above active regions, if the HeI 10830 <TEX>${\AA}$</TEX>line is formed in the upper chromopshere, and it is consistent with the earlyer result from the SMM extreme-ultraviolet observation by Klimchuk(1987, Astrophys. J., 323, 368) (to be submitted. to Astronomy and Astrophysics; an extended abstract)
775
- MARKELOV S. V.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.387-388
- 1996
- 원문 바로보기
The principles to attain improved accuracy in a new controller for large CCD and mosaics detectors with the application of 16- and 32-bit DSP are presented.
776
- HAN WONYONG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.389-390
- 1996
- 원문 바로보기
The CCDs are widely used in astronomical observations either in direct imaging use or spectroscopic mode. However, the areas of available sensors are too small for large imaging format. One possibility to obtain large detection area is to assemble mosaics of CCD, and drive them simultaneously. Parallel driving of many CCDs together rules out the possibility of individual tuning; however, such optimisation is very important, when the ultimate low light level performance is required, particularly for new, or mixed devices. In this work, a new concept is explored for an entirely novel approach, where the drive waveforms are multiplexed and interleaved. This simultaneously reduces the number of leadout connections and permits individual optimisation efficiently. The digital controller can be designed within a single EPLD (Erasable Programmable Logic Device) chip produced by a CAD software package, where most of the digital controller circuits are integrated. This method can minimise the component. count., and improve the system efficiency greatly, based on earlier works by Han et a1. (1996, 1994). The system software has an open architecture to permit convenient modification by the user, to fit their specific purposes. Some variable system control parameters can be selected by a user with a wider range of choice. The digital controller design concept allows great flexibility of system parameters by the software, specifically for the compatibility to deal with any number of mixed CCDs, and in any format, within the practical limit.
777
- LA DAIL
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.83-91
- 1996
- 원문 바로보기
We present a model that rotating primordial blackholes(PBHs) produced at the end of inflation generate the random, non-oriented primordial magnetic field. PBHs are copiously produced as the Universe completes the cosmic phase transition via bubble nucleation and tunneling processes in the extended inflation hypothesis. The PBHs produced acquire angular momentum through the mutual tidal gravitational interaction. For PBHs of mass less than 1013g, one can show that the evaporation (photon) luminosity of PBHs exceeds the Eddington limit. Thus throughout the lifetime of the rotating PBH, radiation flow from the central blackhole along the Kerr-geodesic exerts torque to ambient plasma. In the process similar to the Bierman's battery mechanism electron current reaching up to the horizon scale is induced. For PBHs of Grand Unified Theories extended inflation with the symmetry breaking temperature of <TEX>$T_{GUT}\;\~\;10^{10}$</TEX> GeV, which evaporate near decoupling, we find that they generate random, non-oriented magnetic fields of <TEX>$\~10^{-11}G$</TEX> on the last-scattering surface on (the present comoving) scales of <TEX>$\~O(10)Mpc$</TEX>.
778
- HUANG KELIANG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.105-106
- 1996
- 원문 바로보기
In this paper, we present observations of absorption line spectrum of QSO 1225+317 with resolution of 18 km <TEX>$sec^{-1}$</TEX>. Four possible new heavy element line systems are identified. The properties of Lyman <TEX>$\alpha$</TEX> forest lines are discussed.
779
- LEE YOUNGUNG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.187-188
- 1996
- 원문 바로보기
We have mapped <TEX>$1 deg^2$</TEX> region toward a high latitude HII region S73 (l, b) = (<TEX>$37^{\circ}.69$</TEX>, <TEX>$44^{\circ}.55$</TEX>) and associated molecular cloud in <TEX>$^{12}CO$</TEX> J = 1 - 0, and <TEX>$^{13}CO$</TEX> J = 1 - 0, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. A high resolution autocorrelator is used to resolve extremely narrow CO linewidths (FWHP < 1 km/s) of the molecular cloud. Though the linewidths are very narrow, it is found that there is systematic velocity gradient in the molecular gas associated with the H II region. Both of <TEX>$^{12}CO$</TEX> and <TEX>$^{13}CO$</TEX> averaged spectra are non-gaussian, and there are obvious blue wings in the spectra. It is remarkable that the linewidths at the blueshifted region are broader than those of the rest of the cloud. The CO emission does match well with the dust emission.
780
- PANDEY A. K.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.179-180
- 1996
- 원문 바로보기
The aim of the paper is to analyse the extinction law in the giant H II region NGC 3603. The ratio R is found to be greater than 5.0. In front of the cluster the reddening law is found to be normal. We have obtained a distance of <TEX>$\~$</TEX>5.3 Kpc which is significantly smaller than those adopted so far.