• Proceedings of the KSME Conference
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• 2008.11a
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• pp.481-484
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• 2008

The important factor to evaluate the running safety of a railway vehicle would be the interaction force between wheel and rail(derailment coefficient), for which is one of important factors to check the running safety of a railway vehicle that may cause a tragic accident. Element that analyze derailment coefficient is consisted of wheel load and lateral force. In this paper, studied about method that calculate vertical force(wheel load) by bending load of axle in rolling stocks.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.252-253
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• 2001

The purpose of this work is to investigate the dynamics of an atomic wave packet whose center-of-mass motion is quantized in a resonant standing wave cavity field. The mechanical aspect of the matter-field interaction has been extensively studied In the theme of atomic beam deflection, diffraction, or reflection by a standing-wave field. The effect caused in the behavior of spontaneous emission by the atomic center-of-mass motion, classical and quantized, in a standing wave cavity mode has been studied, and recently the one-atom laser with quantized atomic center-of-mass motion has been investigated. (omitted)

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.124-128
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• 2009

In this study, the effect of multi-step purification or functionalization on physicochemical properties of multi-walled carbon nanotubes (MWNTs)/epoxy (EP) nanocomposites was investigated. The nanocomposites containing multi-step purified MWNTs showed a stronger influence on $T_g$ and increased in mechanical properties in comparison to nanocomposites containing the same amount of only purified MWNTs. Consequently, the multi-step purification of MWNTs led to an improvement of thermomechanical properties of nanocomposites, resulting from improving the intermolecular interaction of MWNTs in epoxy matrix resins.

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.37-40
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• 2006

• Bulletin of the Korean Chemical Society
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• v.14 no.4
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• pp.476-480
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• 1993

The ab initio calculations were performed on ClO and $ClO^+$ using the configuration interaction and M${\phi}$ller-Plesset methods of several different levels of approximation. Three different basis sets, 66 contracted Gaussian-type orbitals,6-31$G^*$ and 6-311$G^*$, were employed in this calculation. The results of calculation were compared with the experimental values of ClO. The values from the calculation with 66cGTO basis set gave excellent agreement with the experimental values. The spectroscopic constants of $ClO^+$ were also predicted.

• Structural Engineering and Mechanics
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• v.5 no.2
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• pp.149-165
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• 1997

A dynamic time-history analysis of the coupled internals and core in the vertical direction is performed as a part of the fuel assembly qualification program. To reflect the interaction between the fuel rods and grid cage, friction element is developed and is implemented. Also derived here is a method to calculate a hydraulic force on the reactor internals due to pipe break. Peak responses are obtained for the excitations induced from earthquake and pipe break. The dynamic responses such as fuel assembly axial forces and lift-off characteristics are investigated.

• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.147-157
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• 2006

This paper represents a numerical study of the flow field due to the interactions between a pair of vortices produced by vortex generators in a rectangular channel flow. In order to analyze longitudinal vortices induced by the vortex generators, the pseudo-compressibility method is introduced into the Reynolds-averaged Navier-Strokes equations of a 3-dimensional unsteady, incompressible viscous flow. A two-layer $k-{\epsilon}$ turbulence model is applied to a flat plate 3-dimensional turbulence boundary to predict the flow structure and turbulence characteristics of the vortices. The computational results predict accurately the vortex characteristics related to the flow field, the Reynolds shear stresses and turbulent kinetic energy. Also, in the prediction of skin friction characteristics the computational results are reasonably close to those of the experiment obtained from other researchers.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.4
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• pp.165-169
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• 2004

This paper reports a miniaturized conductor-backed CPW (CBCPW) bandpass filter based on a thin film polyimide layer coated on CMOS-grade silicon. With a 20 ${\mu}{\textrm}{m}$-thick polyimide interface layer and back metallization on the CMOS-grade silicon, the interaction of electromagnetic fields with the lossy silicon substrate has been isolated, and as a result a low-loss and low-dispersive CBCPW line has been obtained. Measured attenuation constant at 20 GHz is below 1.2 ㏈/cm, which is compatible with the CPW on GaAs. In addition, by using the proposed CBCPW geometry, miniaturized BPF for Ku band application is designed and its measured frequency response shows excellent agreement with the predicted value with validating the performances of the proposed CBCPW geometry for RFIC interconnects and filter applications.

• Journal of Mechanical Science and Technology
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• v.20 no.9
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• pp.1323-1338
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• 2006

An analytical method to estimate the coupled frequencies of the circular plate submerged in fluid is developed using the finite Fourier-Bessel series expansion and Rayleigh-Ritz method. To verify the validity of the analytical method developed, finite element method is used and the frequency comparisons between them are found to be in good agreement. For the perforated plate submerged in fluid, it is almost impossible to develop a finite element model due to the necessity of the fine meshing of the plate and the fluid at the same time. This necessitates the use of solid plate with equivalent material properties. Unfortunately the effective elastic constants suggested by the ASME code are found to be not valid for the modal analysis. Therefore in this study the equivalent material properties of perforated plate are suggested by performing several finite element analyses with respect to the ligament efficiencies.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.191-192
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• 2002

The scuffing failure is a critical problem in modern machine components, especially for the requirement of high efficiency and small size. In this study. scuffing experiments are conducted using Acoustic Emission(AE) measurement by an indirect sensing approach to detect scuffing failure. Using AE signals we con get and indication about the state of the friction processes, about the quality of solid and liquid layers on the contacting surface in real time. The FFT(Fast Fourier Transform)analyses of the AE signal are used to understand the interfacial interaction and the relationship between the AE signal and the state of contact is presented.