• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.54.2-54.2
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• 2015

Within 100 pc of the Galactic Centre the tidal field is extremely strong. We investigate the survival of star clusters of different masses in strong tidal fields. We show that dense low-mass clusters are destroyed by strong tidal fields as the tidal fields add energy to the cluster. Only massive clusters (like the Arches) can survive for more than 1-2 Myr in strong tidal fields. Therefore, in Galactic Centre environments only massive young clusters should ever be observed.

• The Journal of the Korean dental association
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• v.12 no.6
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• pp.369-371
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• 1974

Using 316 plaster models of dental arches of Korean, (ages from 16 to 53) the auther observed the occlusion forms by the Welcker's classifying method. The results were as follows: Psalidontie type is most frequency seen, and its frequency is about 87% in male and about 91% in female. The frequency of occlusal form was decreased in the order of Stegodontie, Lalidodontie and Opisthodontie. Type. There were seldom appeared Progenie and Hiatodontie type.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.17-22
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• 1993

본 연구에서는 진동시 아치미소요소에 발생하는 합응력과 관성력의 동적평 형방정식을 이용하여 불연속 변화단면을 갖는 변화곡률 아치의 자유진동을 지배하는 미분방정식을 유도하고, 이를 해석하여 불연속 변화단면을 갖는 포 물선 아치의 자유진동을 해석하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.69-76
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• 2003

We investigate the fundamental mechanisms of the dynamic instability when the sinusoidal shaped arch structures subjected to sinusoidal harmonic excitation with pin-ends. In nonlinear dynamics, examining the characteristics of attractor on the phase plane and investigating the dynamic buckling process are very important thing for understanding why unstable phenomena are sensitively originated by various initial conditions. In this study, the direct and the indirect snap-buckling of shallow arches considering geometrical nonlinearity are investigated numerically and compared with the step excitation critical load.

• Korean Journal of Mathematics
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• v.14 no.1
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• pp.113-123
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• 2006

The arches may buckle in a symmetrical snap-through mode or in an asymmetry bifurcation mode if the load reaches a certain value. Each bifurcation curve develops as pressure increases. The governing equation is derived according to the bending theory. The balance of forces provides a nonlinear equilibrium equation. Bifurcation theory near trivial solution of the equation is developed, and the buckling pressures are investigated for various spring constants and opening angles.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.2
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• pp.53-63
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• 1995

본 논문의 다경간 연속아치의 자유진동에 관한 연구이다. 다경간 연속아치의 고유진 동수 및 진ㄷㅇ형을 산출하기 위하여 내부지점의 지점조건에 다른 경계조건식을 유도하였다. 아치의 선형은 포물선을 택하였으며, 회전-로울러-회전, 고정-회전-고정의 지점 조건을 갖는 2경간 연속아치에 대한 수치해석 결과를 제시하였다. Runge-Kutta maethod을 이용 하였다. 실제 수치해석예에서는 회전관성이 고유진동수에 미치는 영향을 고찰 하였으며, 무차원 고유진동수와 아치높이 지간길이비 및 세장비 사이의 관계를 분석하였다. 또한 실험을 토아여 이론적인 해석결과를 검증하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.185-192
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• 2002

In this study, we choose the sinusoidal shaped arch with pin-ends subjected to sinusoidal distributed excitation to investigate the fundamental mechanism of the dynamic instability. We derive the nonlinear equations of motion to investigate the instability phenomenon of arch structures and Identify the buckling characteristics of sinusoidal shaped arch structures through the nonlinear eigenvalue analysis with discreted equations of motion by Galerkin's method. We examine that phenomenons which direct snapping and indirect snapping with backbone curves to understand occurrence paths of the dynamic buckling.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.111-117
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• 2001

The problem of the vibration of arches has become a subject of interest for many investigators due to Its importance in many practical applications. The early investigators into the in-plane vibration of rings were Hoppe $^{1)}$ and Love $^{2)}$ . Love $^{2)}$ improved on Hoppe's theory by allowing for stretching of the ring. Lamb $^{3)}$ investigated the statics of incomplete ring with various boundary conditions and the dynamics of an incomplete free-free ring of small curvature.(omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.47-55
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• 2003

Curved beams are one of the most important basic structural units as well as the beams, columns and plates. Most complicated structures consist of only these basic units and therefore it is very attractive research subject to analysis both the static and dynamic behavior of such units including the arches. The problems of free vibrations of curved beams have been the subject of much work due to their many practical applications.(an ellipsis)

• The korean journal of orthodontics
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• v.43 no.6
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• pp.288-293
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• 2013

Objective: This study was aimed at comparing the mandibular arch forms of Korean and Vietnamese patients by using facial axis (FA) points on three-dimensional (3D) models. Methods: Mandibular casts of 68 Korean (Class I malocclusion, 30; Class II malocclusion, 38) and 78 Vietnamese (Class I malocclusion, 41; Class II malocclusion, 37) patients were scanned in their occluded positions and grouped according to arch form (tapered, ovoid, and square). The FA point of each tooth was digitized on the 3D mandibular models. The measurements and frequency distributions of the arch forms were compared between the ethnic groups. Results: The Vietnamese patients had significantly greater intercanine depth and intercanine and intermolar width-to-depth ratios than the Korean patients (p < 0.05). The frequency distributions of the arch forms were also significantly different (p = 0.038), but no sexual dimorphism was found. Conclusions: Vietnamese people tend to have deeper and wider arches than Korean people. The three arch forms are evenly distributed in Korean people, but Vietnamese people frequently have square arches. Clinicians should identify the correct arch form of an ethnic group before initiating orthodontic treatment.