• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.370-371
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• 2003

Poly(lactic acid) is a thermoplastic and biodegradable polymer[1-3]. It has a wide range of application in medical fields such as sutures, screws for bone fractures and drug delivery systems. It has additional potential in other fields like agriculture and packaging. In recent years, there has been an increased interest in star-shaped polymers because they have a higher segment density within the distance of its radius of rotation than linear polymers have under the same conditions.[4] (omitted)

• 대한수학회지
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• 제57권5호
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• pp.1299-1322
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• 2020

We consider closed, star-shaped, admissible hypersurfaces in ℝⁿ⁺¹ expanding along the flow Ẋ = |X|^α-1 F^-β, α ≤ 1, β > 0, and prove that for the case α ≤ 1, β > 0, α + β ≤ 2, this evolution exists for all the time and the evolving hypersurfaces converge smoothly to a round sphere after rescaling. Besides, for the case α ≤ 1, α + β > 2, if furthermore the initial closed hypersurface is strictly convex, then the strict convexity is preserved during the evolution process and the flow blows up at finite time.

• 대한화학회지
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• 제54권6호
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• pp.717-722
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• 2010

Two derivatives of star shaped compounds based on naphthylamine benzene고리에 methoxy기와 ethoxy기가 치환기로 연결되어있는 naphthylamine 관련 화합물을 합성하였다. 합성한 화합물의 전자 및 열적특성을 cyclic voltametry (CV) 및 differential scanning calorimetry (DSC)를 이용하여 조사하였다.

• 제어로봇시스템학회논문지
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• 제1권1호
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• pp.13-19
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• 1995

In this paper, generalized singular value is defined. Using the generalized singular value, robust stability conditions and robust pole placement conditions of structured uncertain systems with star shaped uncertainties are derived. Especially, norm bounded and polytopic uncertainty regions are considered as star shaped uncertainty regions. Linear matrix inequality problems are proposed in order to compute the upper bound of the generalized singular value. The proposed linear matrix inequality problems can be solved by using the convex optimization method.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1993년도 ACT 93
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• pp.761-765
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• 1993

• Macromolecular Research
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• 제16권1호
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• pp.70-72
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• 2008

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.192-198
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• 2016

The distributions of (or constraints for) amplitude and phase around C-points, including Lemon, Mon-Star and Star, are studied. A Cartesian coordinate system with origin at the C-point is established. Four curves, where the azimuthal angles of polarization ellipses are 0°, 45°, 90°, and 135° respectively, are used to determine the distributions. Discussions of these constraints illustrate why Mon-Star is rarer than Lemon or Star in experiments. The transformation relationships between these three polarization singularities (PSs) are also discussed. We construct suitable functions for amplitude and phase according to their constraints, and simulate several PSs of particular shapes. With the development of modulation techniques for amplitude and phase, it is clear that this work is helpful for generating arbitrarily shaped C-points in experiments.

• 한국광학회지
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• 제30권4호
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• pp.142-145
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• 2019

일반적으로 체적형 방식의 디스플레이에는 큐브-모서리 재귀반사(corner cube retroreflector, CCRR)시트와 반투과 거울판이 사용되며, 이는 광원의 빛을 재귀반사시켜 부양영상(floating image)을 만든다. 이러한 기존 CCRR 방식은 광원의 강도를 1/4로 줄이는 반투막 투과 2회의 광손실과 각 단위 CCRR 크기에 의한 영상의 퍼짐 현상이 있다. 본 연구진이 제안하는 '혼성-병풍형' 구조 재귀반사(hybrid-t(transverse directional)-RRMA)는 광퍼짐을 최소화하여 부양영상의 품질을 향상시킬 뿐만 아니라, 광도를 4배로 높이며, 제작상의 편리함도 제공한다. '선형 v자 홈' (linear v-shaped groove)을 '포물선 v자 홈' (parabolic v-shaped groove)모양으로 조절한 재귀반사로 영상의 퍼짐을 개선하여 부양영상을 최적화하였고, '평면(flat wall) 재귀반사' 대신 '곡면(curved planar wall)-재귀반사' 구조를 적용한 '곡면-병풍형-재귀반사판'을 사용하여 반투과 거울판을 없애 반투막에 의한 광손실을 개선하고, 시스템을 단순화하였다.

• 천문학회지
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• 제28권2호
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• pp.177-196
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• 1995

We present UBV CCD photometry of the double cluster NGC 1850 located at the NW edge of the bar of the Large Magellanic Cloud. The color-magnitude diagram shows that NGC 1850 has a prominent population of massive core-He burning stars which is incomparably richer than any other known star clusters. The reddening is estimated from the (U-B) - (B-V) diagram to be E(B - V) = $0.15{\pm}0.05$. We have estimated the ages of NGC 1850 and a very compact blue star cluster (NGC 1850A) located at ${\sim}30''$ west of NGC 1850 using isochrones based on the convective overshooting models: $80{\sim}10$ Myrs and $5{\sim}2$ Myra, respectively. Several evidence suggest that it is probably the compact cluster NGC 1850A that is responsible for the arc-shaped nebulosity (Henize N 103B) surrounding the east side of NGC 1850.

• International Journal of Reliability and Applications
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• 제4권2호
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• pp.71-77
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• 2003

We propose, in this paper, the discrete version of NBU$_{Mg}$and show that the NBU$_{Mg}$ class is preserved under both the non-homo geneous poisson shock model and the general shock model.