• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.340-346
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• 2000

The vibration induced by high speed train running on rail is dealt with as an environmental problem. The train induced vibration is characterized by moving loads of specific frequency contents and soil conditions. In fact various sources are involved the wheal distance, number of cars, speed of operation, drift of rails, structural form vibration, etc. In this paper the characteristics of transferring vibration induced by the operational high-speed train is discussed. And the field measurements was conducted at region from Chungnam Yungi So-jung-myan to Chungbuk Chungwon hyun-do-myun. In the future is would be proposed the fundamental data for establishment of the countermeasure for vibrational reduction of high speed train using the results of the field measurements and quantitative prediction of the vibration level

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.2
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• pp.1-5
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• 1998

$CaSnO_3$ specimens were fabricated by solid reaction method, and their humidity sensitive characteristics have been investigated. Capacitance increases with increasing relative humidity, better humidity sensitivity are shown at lower frequencies. Humidity sensitivity are stable at variable temperatures, and hysteresis phenomenon is shown with adsorption and desorption. Drift phenomenon is exhibited by exposing the specimens in the air, and a decrease of humidity sensitive by contamination is inhibited by heat cleaning.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1544-1545
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• 2011

For quantitative understanding of gas discharge phenomena, we should know electron collision cross section. Processing plasma etching of semiconductor, and research are being used in the etching source $C_4F_6$ gas may be used by itself and mixed with other gases are also used. However, the molecular gas $C_4F_6$ study on the characteristics of the electron transport and the cross-sectional area of the decision is still lacking. Therefore, we understand the electron transport characteristics and analysed the electron transport coefficients. And to understand and interpret physical properties of the ionization coefficient ${\alpha}$/N, and the attachment coefficient ${\eta}$/N in $C_4F_6$ gas.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.220-222
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• 2003

In this paper, we analyze on the discharge characteristics through 1-D simulations in an at plasma display panel discharge cell. The model is based on a Poisson' equation, continuity and drift-diffusion equation. Results are presented in a 95% neon, 5% xenon gas mixture, for a gap length of 100us and a gas pressure of 400Torr at ambient temperature. Results for other gap length are also discussed. As a result, an increase of the gap cause increase of luminous efficiency but with larger sustaining voltage.

• Journal of KSNVE
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• v.11 no.2
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• pp.354-364
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• 2001

The vibration induced by high speed train running on rail is dealt with as an environmental problem. The train induced vibration is characterized by moving loads at specific frequencies and soil conditions. In fact, it is predicted that the vibration sources are involved the wheel distance, number of cars, speed of operation, drift of rails, structural born vibration, etc. In this paper the characteristics of transferring vibration induced by the high-speed train in operation is discussed. Field measurements was conducted at region from Chungnam Yungj So-jung-myan to Chungbuk Chungwon hyun-do-myun. In the near future. these data will be used as the fundamental data for establishment of the countermeasure for vibrational reduction of high speed train using the results of the field measurements and quantitative prediction of the vibration level

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.81-81
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• 2003

We report the plasma blob events that were observed from KOMPSAT-1 (2250 LT, 685-km altitude) and from DMSP F15 (2130 LT,840-km altitude) in the low-latitude ionosphere. The global distribution of blobs showed a season-longitudinal dependence similar to the distribution of the equatorial plasma bubbles, although they were observed along the ${\pm}$15 dip latitudes. The blobs drifted upward relative to the ambient plasmas, and the electron temperatures and H+ proportions were lower within the blobs compared to those in the background. These characteristics of the plasma blobs are very similar to the characteristics of the equatorial plasma bubbles. Then, we suggest that the blobs were originated from the lower altitudes by the mechanism that drives an upward drift of the plasma bubbles. The blob events did not occur in a correlated way with the magnetic activity or daily variation of the solar activity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.63-64
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• 2006

Here we present detailed simulation results of trench field stop IGBTs. Besides the reduced on-state voltage drop there is also an Increase of forward blocking voltage. A trench gate IGBT has low on-state voltage drop mainly due to the removal of the JFET region and a field stop IGBT has high forward blocking voltages due to the trapezoidal field distribution under blocking condition. We have simulated the static characteristics of TIGBT with field stop technology by 2D simulator(MEDICI). The simulated result of forward blocking voltage and on-state voltage drop is about 1,408V and 1.3V respectively at $110{\mu}m$ N-drift thickness.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.925-928
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• 1998

In this paper, the electron transport characteristics in $SiH_4$ has been analysed over the E/N range $0.5{\sim}300[Td]$ and Pressure value 0.5, 1, 2.5 [Torr] by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity. diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50[Td] for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results of Boltzmann equation and Monte carlo simulation have been compared with experimental data by Pollock, Ohmori, cottrell and Walker.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.1023-1027
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• 2000

In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. This paper models of the thermal errors for error analysis and develops on-the-machine measurement system by which the volumetric error are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses, a designed spherical ball artifact, and five gap sensors. In order to analyze the thermal characteristics under several operating conditions, experiments performed with the touch probe unit and five gap sensors on the vertical and horizontal machining centers.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.131-135
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• 1989

Hot electron simulation of silicon using Monte Carlo method was carried out to investigate impact ionization characteristics near the drain of MOSFET's at 77 and 300K. We successfully characterized drift velocity and impact ionization at 77 and 300K employing a simplified energy band structure and phonon scattering mechanisms. Woods' soft energy threshold model was introduced to the Monte Carlo simulation of impact ionization, and good agreement with reported experimental results was resulted by employing threshold energy of 1.7 eV. It is suggested that the choice of the critical angle between specular reflection and diffusive scattering of surface roughness scattering may be important in determining the impact ionization charateristics of Monte Carlo simulation near the drain of MOSFET's.