구상성단 거성들의 분광 연구

이상각,LEE SANG-GAK 한국천문학회 2000 天文學論叢 Vol.15 No.suppl1

A large scatter of the chemical abundances among globular cluster red giants has been observed. Especially the chemical elements C, N, O, Na, Mg, and Al vary form star to star within globular clusters. Except for $\omega$ Cen and M22, most globular clusters could be considered to be monometallic of their iron peak elements within error ranges. The variations in light elements among globuar cluster giants appear much more pronounced than in field halo giants of comparable Fe-peak metallicity. It has been found that in general the nitrogen abundance is anticorrelated with both carbon and oxygen, while it is correlated with Na and AI. These intracluster abundance inhomogeneities can be interpreted either by mixing of nucleosythesized material from the deep stellar interior during the red giant branch phase of evolution or by inhomogeneities of primordially processed material, from which the stars were formed. The simple way of distingushing between two senarios is to obtain the element abundances of main-sequence stars in globular clusters, which are too faint for high resolution spectroscopic studies until now. Both 'evolutionary' and 'primodial' origins are accepted for explanations of abundance variations among red giants and CN-CH anticorrelations among main-sequence stars in globular clusters. This paper reviews chemical abundances of light elements among globular cluster giants, with brief reviews of cannonical stellar evolution of low mass stars after main-sequence and deep mixing for abundance variations of cluster giants, and a possible connection between deep mixing and second parameter.

담배의 노화과정 중 광합성 및 단백질 함량의 변화

이상각,심상인,강병화,Lee, Sang-Gak,Shim, Sang-In,Kang, Byeung-Hoa 한국연초학회 1995 한국연초학회지 Vol.17 No.1

This study was carried out to obtain the basic data which include the change of the photosynthetic rate and protein content according to growth stage in the process of senescence of tobacco plant The photosynthetic rate was the maximum with 26.31$\mu$mol.CO2/m2.sec and stomatal resistance was the minimum with 0.2552cm/sec at 15th days after leaf emergence. However, after 50 days the photosynthesis was very little occurred. During leaf developments the number of chloroplast was increased and reached at the maximum at 25th days after emergence of leaf, thereafter, it was decreased gradually. The content of protein increased continuously and showed the highest value at 15th days after leaf emergence. The degradation rate of soluble protein was more rapid than that of insoluble protein at early stage of senescence. The range of decrement in the insoluble protein was low at late stage of senescence. The content of Rubisco, the key enzyme of photoamthesis, corresponded to about 50% of soluble protein and reached to the maximum at 150 days after leaf emergence. As the senescence progressed, the content of large subunit(UV) of Rubisco showed a tendency to decrease more rapidly than that of small subunit(SSU). The total amount of amino acids was the highest at 15th days after leaf emergence.

4도 대물 프리즘 건판에서 PDS에 의한 스펙트럼 지수 측정

이상각,백원근,홍승수,Lee, Sang-Gak,Baek, Won-Geun,Hong, Seung-Su 한국천문학회 1993 天文學論叢 Vol.8 No.1

In order to check whether the 4-degree objective prism spectra can be used for deep spectroscopic studies of galactic structure, we measured the Rose(1984)'s seven indices between 3500 A and 4400 A for 19 Hyades stars on the Kiso Schmidt prism plate, K3496. By comparing the $4^{\circ}$-indices with those of Rose(1984), we have found that $H{\delta}/FeI$, $H{\gamma}/4325$, and P(3912)/P(CN) measured on the 4-degree prism spectra, are still useful for the derivation physical parameters.

PDS 측정 구경과 속도가 스펙트럼선에 주는 영향

이상각,오승준,김은혁,Lee, Sang-Gak,O, Seung-Jun,Kim, Eun-Hyeok 한국천문학회 1993 天文學論叢 Vol.8 No.1

The variation of instrumental profile for the different scan speed of PDS is estimated as FWHM of the assumed Gaussian Profile. The effects of scan speed and scan aperture of PDS on the objective prism spectrum analysis are investigated for 8 combinations of scan speed and scan aperture. Amomg them. D1 apture with 15 csu is found to be the most optimum choice for measuring KISO objective prism film. We suggest the preliminary test study of the scan speed and aperture for the optimum use of PDS for any massive scan of spectra. The optimum scan speed and aperture depends on the dispersion of spectrum as well as the type of phtographic emulsion.

영성문화자원으로서 남양성모성지의 가치를 통한 지역관광활성화 연구

이상각(Lee, Sang-gak),양승탁(Yang, Seung-tak) 한국문화융합학회 2019 문화와 융합 Vol.41 No.3

This study has been done for the purpose of activating local tourism by utilizing resources that hold attraction as spirituality cultural resources. These include holy and religious sites as well as healing tourism. Furthermore, if religious facilities are included to develop various programs, these will be great resources for activating local tourism. Therefore, this research tries to suggest strategies for linking The Shrine of Our Lady of the Rosary of Namyang, located in Hwaseong, Gyeonggi do, with local tourism; this has been done by estimating its value as a religious facility and spirituality cultural resource, and considering its preservation value as a tourism resource. In the case of this area, a cathedral and peace cultural sharing center are being built by a global architec and these areas will be used not only as religious facilities but also as a concert hall, library, and exhibition hall. What is more, these will be social and cultural facilities for local residents. The value of this structure, The Shrine of Our Lady of the Rosary of Namyang, has been estimated through the Contingent Valuation Method (CVM). For this contingent valuation, a survey was conducted from January 15, 2018 to February 28, 2018. This survey identified locals here and visitors illingness to make a donation for establishing The Shrine of Our Lady of the Rosary of Namyang and analyzed the responses empirically. Based on the result from CVM, WTP truncated mean of the value of The Shrine of Our Lady of the Rosary of Namyang is approximately 329,273 Korean Won per house. The total preservation value is expected to be 102.5 billion Korean Won. Such a value may show major donation willingness from Catholics, as this is a religious facility. However, as a result of estimation based on a logit model, main variables affecting donation intention include suggested price, level of support for facility establishment, and local identity. This implies that enhanced local identity may influence payment value of local spirituality cultural resources; also, level of support for establishing a cathedral and peace cultural center affected its payment value as well. The value of The Shrine of Our Lady of the Rosary of Namyang as a spirituality cultural resource is confirmed through this research. If its image as a local tourism resource is promoted through development of various programs, it will lay a strong foundation for activating local tourism. 본 연구는 영성문화자원으로서 관광적 매력을 지닌 자원의 활용을 통해 지역관광의 활성화를 위한 관점에서 진행되었다. 영성문화자원은 성지관광, 종교관광, 치유관광의 개념을 포함한 보다 넓은 범위의 활동을 위한 자원이 될 수 있으며, 종교적 시설을 이용하여 다양한 프로그램을 활용한다면 지역관광 활성화에 기여할 수 있는 자원이 될 수 있다. 따라서 경기도 화성시에 위치한 남양성모성지를 대상으로 종교적 시설인 영성문화자원의 가치를 추정하여 단순한 시설적 가치 외에 관광자원으로서의 보존가치를 파악해 봄으로써 지역관광과 연계할 수 있는 전략을 제시하고자 하였다. 특히 남양성모성지의 경우 세계적인 건축가에 의해 대성당과 평화문화나눔센터가 건립중이며, 이러한 시설은 단순 종교시설이 아닌 콘서트홀, 도서관, 북카페, 상설 및 기획전시관 등으로 이용될 예정이며, 지역주민을 위한 사회 문화적 시설로 활용될 예정이다. 이에 가상가치추정법(CVM)을 통해 남양성모성지의 건축물 건립에 대한 가치를 추정하였다. 가치추정을 위해 2018년 1월 15일부터 2월 28일까지 설문조사를 실시하였으며, 총 374명의 의견을 토대로 남양성모성지의 건축물 건립에 대한 개발기부금의 명목으로 지불의사를 파악하여 실증분석에 활용하였다. CVM을 통해 추정된 남양성모성지의 가치는 절단된 평균값(WTP truncated mean)을 기준으로 할 경우 가구당 329,273원으로 추정되었으며, 총 보존가치는 약 1,025억 원으로 추정되었다. 이는 종교적 시설이라는 특성 상 천주교 신도 여부가 지불의사에 많이 반영되긴 하였으나, 로짓모델 추정 결과 지불의사에 영향을 미치는 주요 변수로 제시금액, 시설 건립에 대한 지지도, 지역의 정체성 등이 영향을 미치는 것으로 나타났다. 이는 결과적으로 지역에 대한 정체성의 향상이 지역 내 영성문화자원에 대한 지불가치에도 영향을 줄 수 있으며, 대성당과 평화문화나눔센터 등의 건립에 대한 지지도 역시 영성문화자원에 대한 지불가치에도 영향을 주는 것을 확인하였다. 본 연구를 통해 영성문화자원으로서 남양성모성지의 가치를 확인하였으므로, 향후 이러한 시설을 기반으로 다양한 프로그램의 개발을 통해 지역관광자원으로의 이미지를 부각시키고 발전시키면 지역관광 활성화를 위한 기초가 될 수 있을 것이다.

태양 주위에 있는 만기형 주계열성의 자전에 관한 연구

양은수,이상각,Yang, Eun-Su,Lee, Sang-Gak 한국천문학회 1989 天文學論叢 Vol.4 No.1

태양 주위에 있는 만기형 주계열성들의 자전속도 분포와 자전축의 기울기 분포를 조사하였다. 이를 위해 104개의 낱별들과 8개의 Ursa Major Group별들, 그리고 Hyades 성단에 속한 20개의 별들에 대해 각 별들의 자전주기와 반경을 구하였다. 먼저, 별의 자전주기는 대부분 Noyes et al.(1984)의 채충활성도-자전주기 관계식을 이용하여 구했고, 반경은 태양으로부터의 거리가 25pc 이내인 별들을 택해서 Stefan법칙으로 계산하였다. 자전주기와 반경으로부터 결정된 적도자전속도는 0.4<(B-V)<0.8인 별에서는 (B-V)가 증가함에 따라 급격히 감소하고, 기존의 시선자전속도 관측자료에서 이미 밝혀진 위쪽 경계가 나타남과 동시에 아래쪽으로도 자전속도 값의 명확한 경계가 나타났다. 한편, 적도자전속도와 주어진 시선자전속도 값을 비교함으로써 태양 주위에 있는 낱별들의 자전축의 기울기를 구할 수 있었는데, 계산된 기울기는 은위에 무관한 멋대로분포를 따른다는 것을 알 수 있었다. The rotational properties of late-type main sequence stars in the solar neighborhood have been investigated. So rotation periods and stellar radii are determined for 104 field stars, 8 Ursa Major Group stars, and 20 Hyades cluster stars. Most of the rotation periods are derived using the Noyes et al. (1984)'s relation between chromospheric activity and rotation period. Stellar radii are calculated by the Stefan law for the nearby stars within 25 pc from the sun. Rotational velocities at equator are determined by the above rotation periods and stellar radii. Their distribution along the (B-V) color shows an upper boundary and an abrupt drop for the stars in the range of 0.4<(B-V)<0.8, as found from the apparent rotational velocity data. Furthermore, it is apparent that there is an lower boundary of rotational velocity. The inclination of rotation axis to line-of-sight is obtained by comparing the rotational velocity at equator with the apparent rotational velocity given by the analysis of the line profiles. For the field stars, it is found that the inclination has no correlation with the galactic lattitude and follows random distribution.

비(非) Friedmann 우주

현정준,이상각,민호기,Hyeon, Jeong-Jun,Lee, Sang-Gak,Min, Ho-Gi 한국천문학회 1987 天文學論叢 Vol.3 No.1

균질(均質) 등방성(等方性) 공간(空間)을 전제하는 Friedmann 우주의 타당성은 Planck 시기($t_p{\sim}10^{-43}sec$) 이진으로 소급시킬 수 없으므로 시초의 비(非)(Non) Friedmann 우주가 가능하다. 본 연구는 우주시초의 특이성과 관련되는 균질 우주와 비균질 우주의 특성, 지평선과 inflation의 관계를 개관한 다음, $t{\sim}t_p$의 양분자(量子論) 요동(搖動)이나 $t>t_p$의 GUT 상전이(相轉移)로 생기는 inflation 계기에 파생(派生)하는 시공(時空)의 거품들이 이루는 비균질(非均質) 우주의 가능성과 인간원리(人問原理)에 기반을 둔 우주 집단의 관련을 고찰한다.

장주기 변광성의 SiO 메이저 선 세기 변화 연구 : 메이저 펌핑 기작

김은혁,이상각,Kim, Eun-Hyeok,Lee, Sang-Gak 한국천문학회 1993 天文學論叢 Vol.8 No.1

In principle, both radiation and collision are capable of pumping the SiO masers. In order to check which pumping mechanism is more efficient, we calculated the rate equation for our model including the 3 vibrational slates with 7 rotational states of each vibrational slate. Through solving the radiative transfer equation with the Sovolev approximation, we estimated the line profiles from an expanding envelope for several transitions. It is found that the collision works more efficiently than the radiation for the inversion in excited vibrational stales. However in an expanding envelope model we could not get the strong line intensity as observed one because the population inversion is possible only in a small restricted region. For the enough population inversion to get type observed maser intensity. the number density of SiO and hydrogen molecules should be up to about $2{\times}10^5\;cm^{-3}$ and $1{\times}10^9\;cm^{-3}$, respectively, and the inversion should be occured in the region of no Jess than 11014cm.

내염성 식물의 탐색 및 생물학적 염해 모니터링 기술의 개발 2.염분 스트레스에 대한 작물의 출현과 초기 생장 반응

심상인 ( Sang In Shim ),이상각 ( Sang Gak Lee ),강병화 ( Byeung Hoa Kang ) 한국환경농학회 1998 한국환경농학회지 Vol.17 No.2

서울대학교 천문대 16인치 망원경의 추적 성능 향상을 위한 제어 소프트웨어의 개발

정웅섭,이상각,박수종,JEONG WOONGSEOB,LEE SANG-GAK,PARK SOOJONG 한국천문학회 1999 天文學論叢 Vol.14 No.1

We have improved the control and driving system of 16' reflector at Kwanak Observatory at Seoul National University, by completing encoder unit, and by developing programs for correction of errors resulting from hardware defects. The hardware defects of this telescope system are the large backlash and the nonuniform tracking and pointing. The telescope pointing accuracy for RA is improved to a few arc minutes, and that for DEC is several tens of arc minutes. The guiding error is improved to 0.7 arcsec/minute, allowing up to 3 minutes exposure for CCD imaging under typical seeing conditions at the Observatory.