• Journal of the Korean Ceramic Society
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• v.29 no.7
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• pp.572-576
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• 1992

Dielectric constant of ferroelectric ceramics with poling is important in relation to the mechanism of dielectric breakdown. From the research about the dielectric constant variation with poling in tetragonal and rhombohedral phase PZT ceramics, it is known that the dielectric constant after poling is determined by competing effects between increasing effects (compressive stress induced by electrostriction of piezoelectric effects) and decreasing increase in large grain size with poling is smaller than in small grain size.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.49-52
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• 2003

The effects of nitrogen on the deformation behavior of duplex stainless steel have been studied The variation of strength was correlated with the characteristic microstructures. Analysis based on Hall-Petch relation confirmed that nitrogen enhances phase-boundary strengthening effect. The evolution of dislocation structure, slip traces, and misorientation distribution during deformation were also characterized to elucidate the effect of nitrogen on inelastic deformation mechanism.

• Journal of the Korean Society of Safety
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• v.9 no.3
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• pp.67-73
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• 1994

The gas holdup and volumeteric liquid phase mass transfer coefficient with the variation of the concentration of CMC aqueous solution, gas velocity, diameter and area of the draught tube were investigated. As the results of the experiments, the gas holdup and volumetric liquid phase mass transfer coefficient decreased with decreasing the concentration of CMC aqueous solution, increased with increasing the gas velocity and increased with increasing the circulated area ratio of the draught tube.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.299-304
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• 2000

In this paper we investigate accurately the input-output characteristic of single-phase diode rectifier. The diode rectifier has some advantages of simplicity cost and high-efficiency. But it has some defects which THD of input current low PF and voltage drop of output side. In order to compensate it we analyzed using the parameter variation and introduced capacitor insertion method for reducing the distortion and increasing the PF.

• 한국전산유체공학회:학술대회논문집
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• 1997.10a
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• pp.113-119
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• 1997

This paper addresses to the injection pressure effect on the diesel spray. The injection pressure is varied from 10MPa, in general system, upto 200MPa, in high pressured system in order to understand the effect. The gas phase is modelled in terms of the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled following the discrete droplet model approach in Lagrangian form. The droplet distributions, vapor fractions and gas flows are analyzed in various injection pressure cases.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.1
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• pp.64-71
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• 2016

This paper proposes nonlinear behavior in a love model for Romeo and Juliet with an external force of discontinuous time. We investigated the periodic motion and chaotic behavior in the love model by using time series and phase portraits with respect to some variable and fixed parameters. The computer simulation results confirmed that the proposed love model with an external force of discontinuous time shows periodic motion and chaotic behavior with respect to parameter variation.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.653-654
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• 2006

A Pre-emphasis transmitter for DRAM bus system has achieved 3.2Gbps/pin operation at 1.8V supply voltage with 0.18um CMOS process. The transmitter has 800MHz PLL to generate 4 phase clocks. The 4 phase clocks are used for input clock of PRBS and multiplexing. One tap pre-emphasis is used to reduce inter symbol interference (ISI) caused by channel low pass effects. The analog calibration makes the optimized driver impedance independent with the PVT variation.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.3
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• pp.1-7
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• 1992

This paper discusses the self-adaptive equalization technique which has adaptibility to channel characteristics varation without training sequence. The criterion function used in this paper is based on the concept of cumulant matching. This function can be applied to nonminimum phase channel, and we can verify the fact that if the constrained condition is satisfied. this criterion has no local optimum. As the adaption algorithm, the normalized gradient-searching technique is used. Simulations verify the performance of our method in case of 8PAM, 8PSK(CCITT V.27), 16QAM(CCITT V.29) sources and three type nonminimum phase channels.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1038-1040
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• 1993

Single phase AC to DC Boost-converter which is control led with a variable hysteretic current mode for improvent of input power factor makes high power factor possible. Power Factor correction circuit can be identified with a determination of each parameters. A simaluation and experiment result to load and parameter variation is examined.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.3
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• pp.129-138
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• 2019

In this work, we propose detection method for ionosphere storm that occurs locally using widespread GNSS reference stations. For ionosphere storm detection, we compare ionosphere condition with other reference stations and estimate direction of movement based on ionosphere time variation. The method use carrier phase measurement of dual frequency, for accuracy and precision of test statistics, are evaluated with multiple GNSS reference stations data.