• 천문학회보
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• 제37권1호
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• pp.101.2-101.2
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• 2012

An asteroid family is a population of asteroids in the proper orbital element space (a, e, i), considered to have been produced by a disruption of a large parent body presumably through a catastrophic collision. Asteroid families offer unique opportunities to reconstruct and characterize the break-up history of airless bodies in the main-belt. The Maria family is a typical old population (~3${\pm}$1 Gyr) of asteroids that have undergone significant collisional and dynamical evolution in the history of the inner Solar System; it is also believed to be one of the candidate source regions for giant S-type near-earth asteroids (NEAs). However, to date, physical characteristics of this family members such as rotational periods have been known only for 61 of the larger asteroids among 3,230 objects, which accounts for less than 2 percent of the family. In this presentation, we provide some preliminary results of our recent study: out of more than dozen of the family members, lightcurves for eight objects have been obtained for the first time. We plan to increase the number of target objects, and investigate evidences for the Yarkovsky/YORP effect on Maria family based on our observations.

• 천문학회보
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• 제43권1호
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• pp.51.2-51.2
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• 2018

Polarimetry is a powerful technique to investigate the physical properties of surface materials on airless bodies in the solar system. It is known that the degree of linear polarization changes as a function of the phase angle (the angle between Sun-target-Observer). Especially, the dependency of the polarization degree at large phase angle allows us to obtain information related to the particle size and porosity, which is difficult to be determined via other observation techniques (i.e., photometry and spectroscopy). However, despite the advantage, only a few asteroids were observed with polarimetric devices at large phase angles. Here, we present our new polarimetric research of Near-Earth Asteroids (NEAs) observed at the large phase angles. Among the NEAs, we focus on S- and Q-type asteroids, which include: (331471) 1984 QY1, (90075) 2002 VU94, and (66391) 1999 KW4. The observation was conducted using the Pirka 1.6-m Telescope at the Nayoro Observatory of Hokkaido University at the phase angles ${\alpha}{\sim}100degree$, which provides us the maximum polarization degrees of these objects. Considering the observational results together with two objects ((1566) Icarus and (4179) Toutatis) in reference papers [1], [2], we will discuss the implication of the regolith size on their surfaces.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.41-42
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• 2012

High temperature / high pressure spray equipment using a conventional method, unlike spray polyurea adjustable pot life and yellowing caused by UV light and chemicals do not occur, or discoloration of Self-Leveling Type of rugged hand-polyurea resin for technology development is underway. This new concept of polyurea resin roller, brush, airless spray, and they installed easily using the unfamiliar labor, and curing time of approximately four hours to gain control of the glass because it is Pot. Construction, but does not like the spray polyurea resin, compared to the existing degradation of the adhesion strength is concerned. In this study, Self-Leveling Type Manual of polyurea resin adhesion strength of target deterioration Let's minimize problems by reviewing existing domestic and infrastructure long-term durability for long life of the facility is to obtain.

• 한국항공우주학회지
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• 제39권8호
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• pp.719-724
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• 2011

비공기압 타이어(Non-Pneumatic tire)는 공기압 타이어와는 다르게 스포크(Spoke)로 공기압의 역할을 담당하는 새로운 타이어이다. 이 타이어는 공기압 타이어의 펑크에 대한 위험과 공기압 유지가 필요 없는 장접을 가졌으며, 공기가 존재하지 않는 우주에서도 사용이 가능하다. 본 연구에서는 음의 각으로 이뤄진 허니컴 구조의 비공기압 타이어를 수직 하중에 따른 접지압을 구하여, 이를 공기압 타이어와 비교하였다.

• Journal of Chest Surgery
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• 제29권6호
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• pp.621-625
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• 1996

"중엽증후군"의 용어는 Grahaml)등에,의해 처음 기술되어졌으며 대개 비후된 림프절에 의해 기관지 가 외부적으로 압박되 어 발생된다고 하였다. 환자들은 거의 증상이 없을 수 있으나 가장 흔한 발현 증상 은 기침, 호흡 곤란, 반복되는 발열, 객혈, 그리고 흥통 등이다. 진단방법은 흉부 X선, 기관지경검사, 기 관지조영술, 흉부컴퓨터단층될영 등이며 대개 공기가 없이 압축된 중엽이 중요한 소견이다. 본 저자들은 1990년 3월에서 1995년 5월까지 15례의 중엽증후군을 경 험하였으며 그 중 11례에서 수술 적 치료를 시행하였다. 중엽 증후군의 환자에서 수술적용은 악성 종양이 의심되거나,비가역적 기관지 확장증,기관지협착증,약물 치료에 호전이 없는 경우, 치료후 반복되는 감염 등의 경우에 시행하였다. 수술은 중엽절제술 8례,중엽 및 하엽절제술2례,상엽 및 중엽절제술 1례를시술하였다. 수술후 병리조 직소견상 결핵 6례, 만성감염 3례, 악성 종양 1례, 국소적 출혈 1례의 소견을 보였다 술후 합병증은 2례에서 발생하였으며,그 중 1례에서 술후 폐허탈, 1례에서 간장장애를 경험하였으며 치유되었다.였으며 치유되었다.