• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.856-858
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• 2003

Biotop map can be utilized in the urban area for nature conservation and impact assessment for the proposed activities. High resolution satellite data such as IKONOS and KOMPSAT1-EOS were used to classify land use activities in biotop mapping. After land use classification, field -check was done to survey the wildlife and vegetation. These maps were combined and the boundaries were delineated to produce the biotop map. Within the boundary the characteristics of each polygon were identified, and named. This study was carried out at Daedok Science Town in Taejeon Metropolitan Area. The purpose of this study is to produce the biotop map using high resolution remote sensing data together with other ground data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.75-76
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• 2006

In this paper, the polycrystalline silicon photodiodes utilizing vertically directed current path are investigated. The location of electrodes is considered with the grain direction and the current path. The relationships between grain boundaries and characteristics of photodiode are simulated to apply the vertically grown polycrystalline silicon to photodiodes. From the results, the vertically grown polycrystalline silicon photodiode is a potential candidate for CMOS image sensor. However, the increment of dark current related to grain boundaries should be reduced.

• MALSORI
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• no.35_36
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• pp.157-173
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• 1998

This is a pilot study on applying the Rise/Fall/connection(RFC) model to Korean intonation tot speech synthesis. RFC model contains successive intonation events, which can be pitch accents and intonation boundary tones. The intonation contour of RFC model is composed of piecewise linear curves of rise, fall, and connection elements, and each element can have any amplitude and duration. In this paper, elements of RFC model is slightly modified to accommodate the characteristics of Korean intonation. Subjective preference test was conducted to compare the modified RFC model with the original one. The results show that the intonation contour produced by the modified RFC model is perceptually indistinguishable from that of the original RFC model, while the former requires less number of labels than the latter.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.367-373
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• 2001

The effect of characteristic of surface roughness and roughness patterns on friction and sliding wear was studied experimentally under reciprocating boundary lubricant sliding conditions. The test was conducted with specimens which have various arithmetic mean value and roughness pattern under the condition of different normal load. The experimental results show that the friction coefficient is decreased because of oxidation mass and valley effect as the normal loads increasing It was found that the specimens with surface roughness with a transverally oriented pattern have a smaller firction coefficient than the other two roughness patterns under the condition of the roughness values of Ra=0.5 and Ra=0.2 .

• Tribology and Lubricants
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• v.13 no.2
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• pp.89-95
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• 1997

This paper considers two dimensional analysis for lubrication between the single piston ring and the cylinder liner. The piston ring is treated as a reciprocating, hydrodynamic bearing with combined sliding and squeeze motion. Reynolds' equation is used, to model lubrication with Reynolds' cavitation boundary condition. This analysis is developed to get the cyclic variation of minimum film thickness and viscous frictional force. Two types of piston ring face shape are considered. This result can be used to study the influence of ring shape design parameter to improve the characteristics of sealing and lubrication.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.334-339
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• 2001

The nonlinear vibration characteristics of hydrodynamic journal bearings with a circumferentially groove are analyzed numerically when the external sinusoidal disturbances are given to the rotor-bearing system continuously. Also, the cavitation algorithm implementing the Jakobsson-Floberg-Olsson boundary condition is adopted to predict cavitation regions in the fluid film more accurately than conventional analysis which uses the Reynolds condition. It is found that the difference between linear and nonlinear analysis is much more remarkable as the amplitude of external disturbance increases, and it depends upon the excitation frequency of external disturbance. It is also shown that the cavity region in the fluid film is increased as the amplitude or excitation frequency of external disturbance increases. The whirling center of the steady state orbit moves closer to the bearing center as the amplitude or the excitation frequency of the external disturbance increases because of smaller range of full film region.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.9-12
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• 2005

The rapid thermal response (RTR) molding is a novel process developed to raise the temperature of mold surface rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly to the ejection temperature. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filing difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. In order to take into account the effects of thermal boundary conditions of the RTR mold, coupled analysis with transient heat transfer simulation is suggested and compared with conventional isothermal analysis. The proposed coupled simulation approach based on solid elements provides reliable thin wall flow estimation fur both the conventional molding and the RTR molding processes

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.430-430
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• 2010

MICC 방법으로 제작된 TFT는 large grain과 그에 따른 grain boundary의 감소로 인하여여, 소자의 전기적 특성을 좋게 할 수 있다. 본 연구에서는 bi-layer channel의 large grain size TFT를 제작하여 소자의 전기적 특성을 비교하였다. Channel의 width / length의 크기는 각 각의 경우 $7/5{\times}2$, $10/5{\times}2$, $15/5{\times}2$ (${\mu}m$)로 하였다. 소자의 성능 측정 결과 Field-effect mobility의 경우에는 channel width가 증가할 수록 감소하는 경향성을 나타내었으며, Threshold voltage의 경우에는 조금 감소하는 경향성은 있었으나 변화의 폭이 매우 작았다. Output characteristics 의 경우에는 모든 set에서 좋은 saturation 특성을 보였다. 이것은 current croding이 없었다는 것을 의미하는데, 큰 grain size로 인한 효과로 해석 할 수 있다. 본 연구에서는 bi-layer channel에서 corner effect에 중점을 두어 소자의 전기적 특성 변화에 대하여 논하였다.

• Water for future
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• v.20 no.1
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• pp.49-54
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• 1987

A numerical analysis of the characteristics of wave reflection over rippled beds (sand bars) was carried out By Boundary Element Method(B.E.M) using linear elements. It is assumed that the incident wave is normal and oblique to the rippled beds and the wave may be and the escribed by two-dimensional linear theory. The accuracy of the computational scheme is investigated by comparing the laboratory data, the analytic measured results of the other researchers. The B.E.M results for the normal incident wave is held for the mechanism of the resonant Bragg reflection at the point where the wave length of the bottom undulation is one half the wave length of the surface wave.

• Journal of Welding and Joining
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• v.10 no.3
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• pp.40-53
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• 1992

고온고압장치(High Temperature and Pressure Vessels)의 적용을 위한 기초연구로서 9Cr-1Mo강 용접부의 연화특성에 대하여 검토하였다. 9Cr-1Mo 강재에 Bead-on-Plate용접을 실시한 후, 용접부의 기계적 성질과 그 현미경조직관찰 및 미세경도를 측정한 결과, As-Welded 및 용접 후열처리(PWHT)등의 조건에 관계없이 용접열향부의 변태역과 템퍼링역의 경계에서 모재의 경 도보다 낮은 경도값(연화역)을 나타내었으며 이러한 원인은 결정립계(Grain boundary)에 석출 되는 탄화물의 형성에 의한 뜨임 현상임이 판명되었다.