• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.39-42
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• 1993

In this paper, we performed theoretical simulation for directional coupler using BPM program. Simulation results shored that the optimum optical waveguide refractive index between the guides were 3$\mu\textrm{m}$. Using the parameters of n$_1$=2.25, n$_2$=2.25, n$_3$=2.2, gap=3$\mu\textrm{m}$, W= 30$\mu\textrm{m}$, $\Delta$z=0.l$\mu\textrm{m}$, λ=1.5$\mu\textrm{m}$, we decided other design parameters. When we applied 40[V] in the optimum condition of the directional coupling effect, we concluded the refractive index variation of 0.001.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.134-136
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• 1993

Microelectronic fabrication technology .is based on the use of lithsgraphy to create small linewidths and patterns that make up ULSI. In previous papers, we discussed the theoretically calculated values such as ion range, ion concentration,ion transmission coefficient and the defocused ion beam-induced characteristics in a-Se$_{75}$Ge$_{25}$. In this paper, the typical Monte Carlo (MC) simulation results and p개cedures for the focused ion beam lithography were presented. The interaction and scattering of ions with the resist depend on the beam energy, impact parameter arid resist parameters. For ion exposure simulations, the quantity of interest is the spatial distribution of energy deposited by ions in the resist due to interaction phenomena with resist ions.s.s.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.249-258
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• 2004

We investigated structural phases of potassium intercalated into carbon nanotubes using a structural optimization process applied to atomistic simulation methods. As the radius of carbon nanotubes increased, structures were found in various phases from an atomistic strand to multishell packs composed of coaxial cylindrical shells and in helical, layed, and crystalline structures. Numbers of helical atom rows composed of coaxial tubes and orthogonal vectors of a circular rolling of a triangular network could explain multishell phases of potassium in carbon nanotubes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.878-881
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• 2002

Energy distribution function for electrons in $SF_6+Ar$ mixtures gas used by MCS-BEq algorithm has been analysed over the E/N range 30 ~ 300[Td] by a two term Boltzmann equation and by a Monte Carlo Simulation using a set of electron cross sections determined by other authors, experimentally the electron swarm parameters for 0.2[%] and 0.5[%] $SF_6+Ar$ mixtures were measured by time-of-flight(TOF) method, The results show that the deduced electron drift velocities, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients and mean energy agree reasonably well with theoretical for a rang of E/N values. The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of the molecules.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.79-82
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• 1999

This paper presents a study of cold combined forward-backward extrusion product. The case of product with thin wall in piercing process occur defects of deformation and breakdown during piercing process and the center web of product with thin thickness cause flow defect. Such defect is made by the difference of material flow. Methods of the material flow control in the two directions and forming process to remove this flow defect is proposed. The effectiveness of the proposed methods is examined by comparison experiment and finite element simulation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.515-518
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• 2002

In this study, the ellipsoidal cap type magnetic pole structure was proposed for the electro-magnet in B-H curve tracer. From the simulation for the electro-magnet without specimen, the area of effective uniform field(99% range for the central field value) was considerably increased in case of the newly proposed ellipsoidal cap type magnetic pole than that of the conventional simple-inclined cap type magnetic pole. Also, through the simulation for the electro-magnet with permanent magnet specimen(NaFe30), the optimal Positions of the magnetic field measurement sensor(Hall sensor) were found out in each case and the errors were decreased in case of the newly proposed ellipsoidal cap type magnetic pole.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.40-42
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• 2002

Electromigration is atomic diffusion driven by a momentum transfer from conducting electrons. With every new generation of intergrated circuits, interconnect line widths have been reduced and current densities in the interconnect have become higher. This leads to an increase in the threat to interconnect reliability due to electromigration. In this paper, we simulated stress evolution with changing temperature, duty factor(ratio of on time and pulse time), frequency under pulsed DC condition. As a result, we predict MTF(median time to failure) and found that exponent n is affected by changing temperature, duty factor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.18-21
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• 2002

As the mask design rules get smaller, the probability of the process failure becomes higher due to the narrow overlay margin between the contact and metal interconnect layers. To obtain the minimum process margin, a tabbing and cutting method is applied with the rule based optical proximity correction to the metal layer, so that the protection to bridge problems caused by the insufficient space margin between the metal layers can be accomplished. The side-lobe phenomenon from the attenuated phase shift mask with the tight design nile is analyzed through the aerial image simulation for test patterns with variation of the process parameters such as numerical aperture, transmission rate, and partial coherence. The corrected patterns are finally generated by the rules extracted from the side-lobe simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.10
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• pp.914-920
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• 2002

This study investigates the mechanism of a dual mode probe that generates both of the longitudinal and shear waves simultaneously with a single FZT element. Most of conventional ultrasonic probes are constructed to generate either longitudinal or shear waves. After poling, PZT has the hexagonal 6mm crystal symmetry. All possible crystal cuts are checked to determine appropriate Euler transformation angles for efficient excitation of dual modes. For the selected cut, performance of the dual mode element is analyzed through numerical simulation and experiments. Results of the analysis determine the optimal crystal cut for simultaneous generation of P and S waves of equal strength.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.402-405
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• 2002

This paper presented the characteristic of Heat-transfer on the winding composed with Epoxy-resin in a 50 kVA cast-resin dry type transformer The resin cast transformer is used widely in supplying electricity systems. However, to know the thermal characteristics of that is very useful in designing, manufacturing, and maintaining, there is no pertinent method to calculate this. In this paper, Based on the results of the physical characteristics and the simulation by commercial software using FEM method, we established the Prototype Model for this. According to that Model, an analysis on a variation of the hottest spot temperature was discussed as a function of thermal conductivity for the individual windings composed with Epoxy-resin. The thermal conductivity of the individual windings with reference to upper way was discussed.