• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.10
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• pp.693-698
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• 1999

Vacuum interrupters have a special asymmetric electrode structure to generate an magnetic field and consequently to increase the interrupting ability. Accordingly 2-dimensional analysis has a large analysis error because radial flux can not be considered. In this paper, in order to analyse the electric field distribution of a vacuum interrupter with arc shield more accurately, 3-dimensional finite element method(FEM) is used. The induced electric potentials of floating shield was increased with the gap distance, which is because the relative position of shield is closer to the fixed contact so that the capacitance distribution inside interrupter is varied. The calculated results also show that the induced potential of shield causes electric field distortion so that the maximum value of electric field in a vacuum interrupter with arc shield is higher than that without one.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.6
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• pp.411-417
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• 2009

The transient shear stress response of an electrorheological fluid is investigated experimentally. The characteristic time constants of an electrorheological fluid sheared between two concentric cylinders were obtained under various electric field strengths and shear rates. Also, two experimental modes are adopted to investigate the effect of the shear flow on the dynamic behavior of the fluid; one is that the electric field is induced before shearing, and the other is the electric field is induced after shearing. From the difference in the response time between two modes, the cluster formation time were obtained. The response times were decreased with the increase of the shear rate, irrelatively of the electric field strength. The cluster formation time were monotonically increased with increase of shear rate, and thereafter, were converged with a certain value.

• ETRI Journal
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• v.26 no.3
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• pp.277-280
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• 2004

The distributions of electric field and induced second-order nonlinearity are analyzed in the periodic poling of optical fibers. A quasi-phase matching efficiency for the induced nonlinearity is calculated in terms of both the electrode separation distance between the applied voltage and generalized electrode width for the periodic poling. Our analysis of the quasi-phase matching efficiency implies that the conversion efficiency can be enhanced through adjusting the separation distance, and the electrode width can be maximized if the electrode width is optimized.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.228-232
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• 2014

The magnetic field generated by the feeding line of a wireless power transfer system induces voltage on the rail of a railway system. The induced voltage of the rail can have a bad influence on the track circuit and on safety. This paper simulated three feeding lines to study the relation between the feeding lines and the induced voltage of the rail; it also proposed magnetic field distribution of the feeding line to reduce the induced voltage.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.9-15
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• 1996

An electric field induced by a point dipole soruce within a conductor-backed lossy dielectric slab above the earth is calculated by anumerical method. the calcualtion is peformed on the plane which is parallel to the conductor plane and containing the point dipole soruce. Computed S$_{21}$ values of two parallel planar dipole antennas and two collinear planar dipole antennas are compared against each other, as well as the electic field magnitudes in those arrangements.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.142-149
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• 2003

Domain switching effect on crack growth in ferroelectric ceramics under combined electric and mechanical loading is investigated. The shape and size of the switching zone is shown to depend strongly on the relative magnitude between the applied electric field and stress field as well as on the ratio of the coercive electric field to the yield electric field. The toughening mechanism is thought to be ferroelectric domain switching leading to the development of a process zone around the crack. Crack-tip stress intensity factor induced by domain switching for the steady state crack growth is numerically obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.620-623
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• 2003

Non-linear behaviors of multilayer piezoelectric ceramic actuator (MCA) were investigated under electrical and mechanical stress. DC 100 V bias was applied to the MCA to obtain displacement. Laser vibrometer, which using Doppler effect, was employed to characterize displacement caused by $d_{33}$ mode of MCA. To understand this non-linear behavior of MCA, displacement was measured and compared under different load states. By increasing load, electric field-induced strain and piezoelectric constant($d_{33}$) of MCA was decreased. We attribute this phenomenon to the domain wall motion and depoling of MCA under heavy load.

• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.48-55
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• 2012

Degradation of performance and life time of a functional material or device thereof is induced, to a great extent, by mass transfer in the material that is driven by various thermodynamic forces imposed intentionally or accidentally during its operation or service. The forces are any gradient of intensive thermodynamic variables, component chemical potentials, electrical potential, temperature, stresses, and the like. This paper reviews electric-field induced degradation phenomena in ionic solid compounds including insulation resistance degradation, crystal shift, microstructural alterations, compositional unmixing, and compound decomposition. Their inner workings are also discussed qualitatively.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.1
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• pp.50-55
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• 1992

Piezoelectric Buzzer which has been generally used requires about 30kV/cm poling process and has the aging effects. In this study, 0.85 PZN - 0.10 BT - 0.05 PT system ceramics with additives of 0 - 2 wt% YS12TOS13T were fabricated and investigated on electromechanical coupling coefficient(kS1pT), electric field induced charge coefficient(dS131T), and sound level. As the results, in the 0.4 wt% YS12TOS13T added composition ceramics compared with the basic, kS1pT was increased from 0.355 to 0.39 and induced piezoelectric d constant increased from 204 to 220 x 10S0-12T (C/N) and sound level of electrostrictive Buzzer has the highest value of 71.5 dB under 8kV/cm bias electric field.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.6
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• pp.341-345
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• 2000

This paper analysed the induced electric field of human body under the 765 kV transmission line considering permittivity and conductivity. As permittivity of human body is very high as 106 at 60 Hz, special numerical computation technique is Surface Charge Method(SCM) for composite media with extremely different properties is applied to reduce calculation error of induced electric field inside the human body.