• Journal of Astronomy and Space Sciences
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• 제4권2호
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• pp.69-80
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• 1987

Okazaki(1997)의 2색(V와B)의 광전측광에 의한 광도곡선을 Wilson and Devinney모델을 이용하여 T LMi의 광전궤도요소를 구하였으며 지금까지 발표된 이 별의 극심시각을 문헌으로 수집하여 궤도공전주기변화를 분석하였다.T LMi의 공전주기 변화는 simusoidal한 주기변화를 나타내며 그 진폭은 $0.^{d}0425$ 이고 장주기변화는 $62.^{y}01$ 로 나타났다. 한편, 이번 연구에서 얻어진 T LKi의 물리적 성질에 따르면 이 별은 "R CMa" 형으로 분류한다는 것은 재검토가 있어야 하겠다.검토가 있어야 하겠다.

• Journal of Astronomy and Space Sciences
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• 제24권2호
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• pp.145-154
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• 2007

접촉 케플러 궤도요소로부터 변환된 NORAD TLE를 정지궤도 위성의 안테나 포인팅에 직접 사용하기 위한 분석을 수행하였다. 일주일에 한번씩 동서방향과 남북방향의 위치유지를 위한 궤도조정을 수행하고 하루에 두 번씩 추력기를 이용한 모멘텀 덤핑을 통해서 궤도가 계속 변하는 통신해양기상 위성에 대해서 변환된 NORAD TLE를 이용한 안테나 포인팅 오프셋 각을 계산하여 위성신호를 수신할 수 있는지 검토하였다. 이를 통해 변환된 NORAD TLE를 사용하여 위성 관제시스템의 안테나 포인팅에 관련된 인터페이스를 간단하게 수행할 수 있음을 보였다. 또한 이심률이 큰 천이궤도에 있어서 위성의 평균 근점각에 따른 변환된 NORAD TLE 값의 차이를 분석하여 천이궤도의 원지점 근처에서의 NORAD TLE 변환 값이 더 좋은 결과를 나타내는 것을 알 수 있었다.

• Journal of Astronomy and Space Sciences
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• 제8권1호
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• pp.53-61
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• 1991

UV light curve of 31 Cygni has been made from the IUE high dispersion specta. The depth of primary minimum of the light curve is 5.2 magnitudes because the B4 star's steep spectral gradient. The light curve has been analyzed by the method of Wilson and Devinney Differential Correction (WD). The radial velocities have been measured using the Mg II h lines. The spectroscopic elements have been determined by the method of WD. The change of the Mg II resonance doublet has been investigated based on the eight representative spectra taken at well distributed orbital phases.

• 전자공학회지
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• 제22권2호
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• pp.37-50
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• 1995

This paper reviews NTT Laboratories' research and development of x-ray lithography during the last ten years since the application of synchrotron orbital radiation(SOR). First, the historical background of x-ray lithograhpy research, NTT's research programs on synchrotron x-ray lithography(SOR lithography), and the current status of NTT's SOR lithography system are overviewed. Then, the key elements of SOR lithography system are reviewed, including the electron storage ring, the x-ray stepper, and the x-ray mask. Finally the appilcation of SOR lithography technology to device fabrication is reported.

• 천문학회지
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• 제8권1호
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• pp.25-27
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• 1975

A time of minimum light for VV Orionis has been determined photographically using techniques developed by Jeong. The observed time of minimum light shows that VV Ori exhibits a constant orbital period. The O-C computed with the light elements given by Eaton is found to be $-0^d$, 0070. An attempt to correct for night-to-night shifts for plates taken on three nights in February and March 1975, was unsuccessful and thus the complete light curve initially planned was not obtained.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.609-614
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• 2013

Extended H$\ddot{u}$ckel tight-binding band structure calculations are used to address the chemical bonding and elastic properties of $Zr_2AC$ (A=Al, Si, P, and S). Elastic properties are interpreted by analyzing the density of states and the crystal orbital overlap population for the respective phases. Our results show that the bulk modulus of these ternary compounds is determined by the strength of Zr-A bonds.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.218-221
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• 2004

The electronic state of ZnO doped with Al, Ga and In, which belong to III family elements in periodic table, was calculated using the density functional theory. In this study, the program used for the calculation on theoretical structures of ZnO and doped ZnO was Vienna Ab-initio Simulation Package (VASP), which is a sort of pseudo potential method. The detail of electronic structure was obtained by the describe variational $X{\alpha}(DV-X{\alpha})$(DV-Xa) method, which is a sort of molecular orbital full potential method. The optimized crystal structures obtained by calculations were compared to the measured structure. The density of state and energy levels of dopant elements was shown and discussed in association with properties.

• 천문학회보
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• 제42권2호
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• pp.80.2-80.2
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• 2017

We present chemical and kinematic properties of the Milky Way's halo system investigated by carbon-enhanced metal-poor (CEMP) stars identified from the Sloan Digital Sky Survey. We first map out fractions of CEMP-no stars (those having no over-abundances of neutron-capture elements) and CEMP-s stars (those with over-enhancements of the s-process elements) in the inner- and outer-halo populations, separated by their spatial distribution of carbonicity ([C/Fe]). Among CEMP stars, the CEMP-no and CEMP-s objects are classified by different levels of absolute carbon abundances, A(C). We investigate characteristics of rotation velocity and orbital eccentric for these subclasses for each halo population. Any distinct kinematic features identified between the two categories in each halo region provide important clues on the origin of the dichotomy of the Galactic halo.

• 천문학회보
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• 제43권1호
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• pp.66.3-67
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• 2018

We present distinct chemical and kinematic properties associated with the inner and outer halos of the Milky Way, as identified by metal-poor stars from the Sloan Digital Sky Survey. In particular, using carbon-enhance metal-poor (CEMP) giants, we first map out the fractions of CEMP-no stars (without strongly enhanced neutron-capture elements) and CEMP-s stars (with a large enhancement of s-process elements) in the inner- and outer-halo populations, separated by their spatial distribution of carbonicity ([C/Fe]). The CEMP-no and CEMP-s objects are classified by their different levels of absolute carbon abundances, A(C). We investigate characteristics of rotational velocity and orbital eccentricity for these sub-classes within the halo populations. Distinct kinematic features and fractions between CEMP-no and CEMP-s stars identified in each halo region will provide important clues on the origin of the dichotomy of the Galactic halo.

• Journal of Astronomy and Space Sciences
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• 제3권2호
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• pp.93-102
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• 1986

정지통신위성을 동서방향으로 궤도 조정을 하기 위해서는 평균경도와 궤도의 이심률에 관해서 동시에 조정하여야 한다. 궤도이심률의 효과는 궤도중심방향의 $e_{c}$ 과 $e_{s}$의 위상면상에서 표시되어야 한다. 평균경도와 궤도이심률에 대한 진화도 얻었다.