• Kyungpook Mathematical Journal
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• v.35 no.1
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• pp.39-75
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• 1995

• Journal of the Korean Mathematical Society
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• v.40 no.4
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• pp.629-639
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• 2003

We give results describing behavior of regions of holomorphic extension of CR functions near boundary points of their domain of definition.

• Journal of KSNVE
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• v.10 no.5
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• pp.865-872
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• 2000

This paper presents the modeling, theoretical formulation, and stability analysis for a combined system of a spinning disc and a head that contacts the disc. In the analytic model, head interference is considered by a rotating mass-spring-damper system together with a frictional follower force on the damped annular discs. The multiple scale method is utilized to perform the stability system that shows the existence of instability associated with parametric resonances. Using the formulated system , instability regions of optical recording disc are investigated with variation of mass, stiffness and friction force of a head, respectively. The simulation results show that the stiffness of a head is the most sensitive parameter on the instability of the disc.

• Journal of the Korean Mathematical Society
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• v.55 no.5
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• pp.1019-1030
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• 2018

In [12,13] the researchers introduced universally convex, universally starlike and universally prestarlike functions in the slit domain ${\mathbb{C}}{\backslash}[1,{\infty})$. These papers extended the corresponding notions from the unit disc to other discs and half-planes containing the origin. In this paper, we introduce universally prestarlike generalized functions of order ${\alpha}$ with ${\alpha}{\leq}1$ and we obtain upper bounds of the second Hankel determinant ${\mid}a_2a_4-a^2_3{\mid}$ for such functions.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.2
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• pp.34-41
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• 1991

In this study, the equations of motion of the thin annular plate with uniform thickness were derived from the classical theory of the plate. In addition the distribution of the inplane stress and the natural frequency due to the change of the ratio of the outer radius to the inner radius was presented by the analytic method using the numerical analysis. Results were compared with those from the experiment. As a result, the strain of rotating circular plate increased as the radius and rpm became greater, and the strain of radial direction was two times greater than that of transverse direction. Besides, it was confirmed that the natural frequency increased according to the decrease of the radius keeping the thickness constant.