• Journal of computational fluids engineering
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• v.15 no.4
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• pp.32-39
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• 2010

In this study, we consider Taylor-Couette flow with the outer cylinder at rest and the inner one oscillating with a mean angular velocity. Varying the mean angular velocity, amplitude and frequency of the oscillation, we investigate the characteristics of modulated Taylor vortices. At a constant mean angular velocity, Taylor vortices intensify as the amplitude increases and frequency decreases. The axial wavenumber is calculated by spectral analysis. When the frequency varies, the axial wavenumber does not change at a constant mean angular velocity and amplitude. But, the axial wavenumber increases, as the mean angular velocity increases.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.772-775
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• 2003

A bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. A force-displacement relation for bushings is important for multibody dynamics numerical simulations. For the nonlinear viscoelastic axial response, Pipkin-Rogers model, the direct relation of force and displacement, has been derived from Lianis model and the sinusoidal input was used for Pipkin-Rogers model, and the affection of displacement with frequency change was studied with Pipkin-Rogers model.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.76-79
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• 1999

The study has been performed for the relation between die and product in forward extrusion by the experiment. Strains of the die have been given by the simple experiment using the strain gauge located at the outer surface of the die and the history of the deformation of the die and product is given by the experiment and Lame's formula. The inner pressure of the die causes the deformation of die that affects the accuracy of dimension and shape of product. The product with accurate dimension and shape can be obtained by analysing elastic deformation of the die during process. The deformation of the die during metal forming process has been usually predicted by the experience of industrial engineer or finite element analysis. But it is difficult to predict the dimension of product at unloading and ejected states. The study has given useful results for the deformation history of the die and product through the experiment and Lame's formula at forward extrusion for solid cylinder and can be applied to the die design for product with accurate dimension.

• Progress in Superconductivity and Cryogenics
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• v.2 no.2
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• pp.44-48
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• 2000

The high temperature superconducting bulk can be used as the rotor of an ac motor. This paper presents the fabrication and test results of a ac motor with HTS bulk rotor. The rotor of a conventional squirrel cage induction motor was replaced with cylinder type YBCO bulk. Height and outer diameter of the HTS bulk was 15mm and 46mm, respectively. Eddy current brake using aluminium disk was used to measure the torque of the HTS motor. No load test, locked rotor test and load test were performed to examine the characteristics of the HTS motor. Test results show the motor can rotate at synchronous speed without any special starting circuit. Maximum output power of the constructed HTS motor was 408W.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1925-1928
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• 1996

In this work, the behavior of conducting wire type particles existing inside the cylinder type coaxial electrode has been systematically investigated by charge simulation method and electrostatic force analysis from the view point of the acquired charging before being lifted off into the gap under the high ac voltage. Spheroidal charge are adopted as a image charge for the CSM analysis in order to calculate the acquired charges of the particles which are erected on the surface of the outer electrode. For this purpose, different material of the particle and their lengths and diameters have been considered in view to calculate their lift-off field, acquired charge and to understand their effect on the lift-off voltage. The results imply that the particle lengths and diameter have an different influence on the particle behavior in GIS system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.6
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• pp.677-684
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• 2003

A new unipolar aerosol charger was developed by using an indirect photoelectric charging. The charger consists of two coaxial tubes, the inner UV lamp wrapped with stainless mesh and the outer Al cylinder. In this study, the effects of flow rate, particle size, and electric field were examined to search the optimal charging conditions with experimental and numerical methods. Monodisperse NaCl particles were fed into an annular space and the particles were charged by negative ions generated from Al plate exposed to the UV light. According to experimental results, the average number of elementary charge on particles increases from 2.5 to 5.5 as particle size increases from 50nm to 130nm at 2.5 L/min and 100V. The average number of elementary charge on particles was maximized at 25V as the electric potential between the stainless mesh and Al plate was varied from 0V to 400V.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.7-12
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• 2005

In heavy industrial fields such as power plant and chemical plant, it is often necessary to restore a damaged part of large machinery or structure which is installed in the hazard working place. In this paper, to evaluate the safety of plastic deformed cylindrical beam a finite element technique has been used. The variations of residual stresses on the process of damaging and restoring for surfaces and cross-sections have been examined. The results show that the maximum von Mises stresses occur outer cylinder surfaces of boundary between cylindrical beam support md cylindrical beam when deformation procedure and restoring force is applied. The maximum residual stress remains 158.6MPa in the inner wall and this value correspond to $53\%$ of yield stress then restoration procedure is finished.

• Applied Microscopy
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• v.1 no.1
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• pp.27-34
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• 1969

The compound eyes of the adult Drosophila melanogaster were. fixed in 1.25 per cent glutaraldehyde and 1 per cent osmium tetroxide buffered with sodium cacodylate at pH 7.2. Double fixed specimens were dehydrated using the alcohol series and embedded in Epon 812. They were sectioned with porter blum and JUM 5B ultra-microtome and then stained with lead hydrooxide and uranyl acetate. All thin sections were examined with Hitachi HS-7 or HU-11 electron microscope. The rhabdomere of the compound eye is composed of numerous microvilli packed, arranged, and projected from inner edge of each retinal cell. Each microvillus consisted of a centrum, about $82{\AA}$ in diameter, surrounded by the substances, about $105{\AA}$ in width, which were bounded with double membrane about $44{\AA}$ in thickness. In each inner edge of the microvilli, there was a cylinder, about $175{\AA}$ in diameter, in parallel with retinal cells, which contained a cylindrical axis about $583{\AA}$ in diameter. The surface of the outer edges .of .the microvilli was bounded with reticullar substances about $500{\AA}$ in thickness.

• Journal of Electrical Engineering and information Science
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• v.2 no.3
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• pp.77-81
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• 1997

In his work, the influence of wire type conducting particles on the insulation reliability of GIS has been systematically investigated when the epoxy resin based dielectric coating was made on he inner side of outer electrode. For this purpose, coaxial cylinder-type electrode was adopted in 362 kV chamber and various sizes of Cu conducting particle were used under different gas pressures. In order to elucidate the coating effect on the gas insulation, different thickness of dielectric coating has been considered and then the lift-off voltage and flashover voltages have been measured. The results shown that the dielectric coating has a remarkable influence by restraining the movement of particle in GIS system, and thus GIS insulation reliability is noticeably improved.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.474-478
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• 2004

A bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. A force-displacement relation for bushings is important for multibody dynamics numerical simulations. For the nonlinear viscoelastic axial response, Pipkin-Rogers model, the direct relation of force and displacement, has been derived from Lianis model and the sinusoidal input was used for Pipkin-Rogers model, and the affection of displacement with frequency change was studied with Pipkin-Rogers model.