• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.13-17
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• 2006

RoeM and AUSMPW+ schemes are two of the most accurate and efficient schemes which are recently developed for the analysis of single phase gas dynamics. In this paper, we developed two-phase versions of these schemes for the analysis of gas-liquid large density ratio two-phase flow. We adopt homogeneous equilibrium model (HEM) using mass fraction to describe different two phases. In the Eulerian-Eulerian framework, HEM assumes dynamic and thermal equilibrium of the two phases in the same computational mesh. From the mixture equation of state (EOS), we derived new shock-discontinuity sensing term (SDST), which is commonly used in RoeM and AUSMPW+ for the stable numerical flux calculation. The proposed two-phase versions of RoeM and AUSMPW+ schemes are applied on several air-water two-phase test problems. In spite of the large discrepancy of material properties such as density, enthalpy, and speed of sound, the numerical results show that both schemes provide very satisfactory solutions.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.490-495
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• 2006

In this research, the design procedure and the design method of a single-phase line-start permanent magnet motor (LSPM) are proposed. In the design procedure, the permanent magnet is designed first and the windings and capacitors are designed later. As well, the points of design of each design parameter are explained. In the design of the single-phase LSPM, the equivalent circuit method is combined with the finite element method (FEM) because it has a shorter analysis time than FEM. The 400 watts single-phase LSPM is designed and manufactured. The characteristics of the manufactured single-phase LSPM are analyzed and experimented. From the analysis result and the experiment result, it is verified that the design procedure and the design method of the single-phase LSPM is valid.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.5
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• pp.289-297
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• 1988

In this paper, the analysis of a generating torque characteristics of 2-phase induction motor driven with the phase control method is presented. The generating torque equations which represent average torque and pulsating torque are derived from the elementary machine model. The calculating equations which can get the values of average torque and pulsating torque is expressed by the parameters of the equivalent circuit of 2-phase induction motor. According to the calculating equations, these performance characteristics are investigated under various conditions. Finally, a strategy to eliminate non-linearity and pulsating torque generated in driving 2-phase induction motor with the phase control method is presented.

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.354-364
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• 2012

In this paper, a new 2-step quadrature phase-shifting digital holographic optical encryption method using orthogonal polarization is proposed and tolerance errors for this method are analyzed. Unlike the conventional technique using a PZT mirror, the proposed optical setup comprises two input and output polarizers, and one ${\lambda}$/4-plate retarder. This method makes it easier to get a phase shift of ${\pi}$/2 without using a mechanically driven PZT device for phase-shifting and it simplifies the 2-step phase-shifting Mach-Zehnder interferometer setup for optical encryption. The decryption performance and tolerance error analysis for the proposed method are presented. Computer experiments show that the proposed method is an alternate candidate for 2-step quadrature phase-shifting digital holographic optical encryption applications.

• The Transactions of the Korean Institute of Power Electronics
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• v.28 no.1
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• pp.59-67
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• 2023

This paper explores the variation of DC-Link current ripple analysis in terms of duty cycle and phase angle of Multi-phase/Multi-stage boost converter. A 2-Stage/1-Stage boost converter DC-Link current is used to determine the difference between the 1st stage diode current and the 2nd stage inductor current. Each stage boost converter diode and inductor current is subordinate to the phase angle and duty cycle. The magnitude of the ripple current is variable according to phase angle and duty cycle. The analysis results are verified by variation of DC-Link current ripple using a 1kW typical 2-stage/1-stage boost converter.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.314-320
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• 2001

A novel mode of parallel operation of a modular 3-phase AC-DC flyback converter for power factor correction along with tight regulation was recently analyzed and presented. The advantage of the proposed converter does not require expensive high voltage and high current devices that are normally needed in popular boost type 3-phase converter. In this paper the detailed small signal analysis of the modular 3-phase AC-DC flyback converter is provided for control purposes and also experimental results are included to confirm the validity of the analysis.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.548-553
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• 2003

The frequency and phase angle of the utility voltage are important in many industrial systems. this paper present a detailed analysis of single-phase digital PLL control for utility connected systems. and its performance under utility conditions with noise is discussed. The experimental results demonstrate phase tracking capability in the single-phase grid-connected operation.

• 전기의세계
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• v.23 no.2
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• pp.39-45
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• 1974

An analysis is developed for the torque characteristics of single-phase induction motors having variable shaded-pole angles. The machanism have two sets of stator windings which one set of stator fed from single-phase sources and other shorted by inserted external impedances. Thus, by phisically rotating one set of stator windings with respect to the other, the only shaded-kpole effect torque performance of a single- phase induction machine and its performance prediction to be expected of the optimum shaded-pole angle can be achieved.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.75-80
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• 2005

The present work was undertaken to numerically analyze the defrosting phenomena of windshield glass. In order to analysis the phase change from frost to water on windshield glass by discharging hot air from a defroster nozzle, the flow and the temperature field of the cabin interior, the heat transfer through the windshield glass, and the phase change of frost should be solve simultaneously. In the present work, the flow field was obtained by solving 3-D incompressible Navier-Stokes equations, and the temperature field was computed from the incompressible energy equation. The phase change process was solved by the enthalpy method. For the code validation, the temperature and the phase change of the driven cavity were calculated. The calculation showed a good agreement with other numerical results. Then, the present code was applied to the defrosting problem of a real automobile, and a good agreement with the experimental data was also obtained.

• Interaction and multiscale mechanics
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• v.4 no.2
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• pp.155-164
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• 2011

The lattice strain evolution within polycrystalline solids is influenced by the crystal orientation and grain interaction. For multi-phase polycrystals, due to potential large differences in properties of each phase, lattice strains are even more strongly influenced by grain interaction compared with single phase polycrystals. In this research, the effects of the grain interaction and crystal orientation on the lattice strain evolution in a two-phase polycrystals are investigated. Duplex steel of austenite and ferrite phases with equal volume fraction is selected for the analysis, of which grain arrangement sensitivity is confirmed in the literature through both experiment and simulation (Hedstr$\ddot{o}$m et al. 2010). Analysis on the grain interaction is performed using the results obtained from the finite element calculation based on the model of restricted slip within crystallographic planes. The dependence of lattice strain on grain interactions as well as crystal orientation is confirmed and motivated the need for more in-depth analysis.