• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.85-87
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• 2012

We present a numerical investigation on gaseous (ethylene-air mixture) detonation in the elastoplastical metal tubes to understand the wall effects associated with the developing detonation instability. The acoustic disturbances originating from the rapidly expanding tube walls reach the detonating flame surface, thereby causing flame distortions and total energy losses. The compressible Navier-Stokes equations with equation of state for gas and elasto-plastic deformation field equations for inert tubes are solved simultaneously to understand the complex multi-material interaction in the rapidly expanding gas pipe. In order to track governing variables across the material interface, we use the hybrid particle level-set and ghost fluid methods to precisely estimate the interfacial quantities. Features observed from the deforming (thin) tube show substantially different behavior when a detonation propagates in the rigid (thick) tube with no acoustically responding wall conditions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.97-102
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• 1993

According as the high integrity of the semi conductor devices is definited required, the concern on the multi-layered wiring, and three-dimensional devices is growing these days. Therefore, plasma-enhanced chemical vapored deposition(PECVD) enables low-teperature process and is widely used, but it causes the instability of the devices due to a lot of impurities within the film. The PECVD oxynitride was formed by changing the gas ratio of (N$_2$O) to (N$_2$+NH$_3$). It's contained a small portion of hydrogen, had higher refrctive index and capacitance than oxide, and showed the capacitance increasement and the chemical stabi1ity. This is caused by nitrogen distribution increase of the interface lather than within the film.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1673-1678
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• 2005

This paper addresses both theoretical and experimental studies of the stability of haptic interfaces during the simulation of virtual Coulomb friction. The first objective of this paper is to present an analysis of how friction affects stability in terms of the describing function method and the absolute stability theory. Two different feedback methods are introduced and are used to evaluate the analysis: an active force feedback, using a motor, and a passive force feedback, using controllable brake. The second objective of this paper is to present a comparison of the theoretical and experimental results. The results indicate that the sustained oscillations due to the limit cycle occur when simulating friction with an active force feedback. In contrast, a passive force feedback can simulate virtual friction without the occurrence of instability. In conclusion, a hybrid active/passive force feedback is proposed to simulate a highly realistic friction display.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.118-120
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• 2003

The behavior of viscous fingerings caused by an external force is investigated by using a two­phase lattice Boltzmann method. The effects of the modified capillary number, the viscosity contrast, and the modified Darcy-Rayleigh number on the instability of interfaces are found. The calculated wave numbers are in good agreement with the theoretical ones in the range of wave numbers smaller than 10, but the calculated ones tend to become smaller than the theoretical ones in higher wave numbers.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.721-728
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• 2003

Nowadays, a lot of enterprise completed the ERP implementation and these ERP-based enterprises consider the construction of WMS or already have done it. However the enterprises which Implemented WMS linked with ERP have many problems In the warehouse management and the reason ran be summarized In two poults First. In the integration point of view, only Interface issue between ERP and WMS was taken into account, therefore it was hard to reflect the phased process change. Second, a large number of WMS functions were tried to implement at the same tune and these attempts caused confusion and Instability which Is Interpreted as a main reason of the WMS failure. This paper presents the phased construction method for the successful implementation or WMS and in the integration point or view, the phased process change appears naturally

• 전자공학회논문지D
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• 제35D권3호
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• pp.11-17
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• 1998

Although GaAs HBTs are very attractive for high power amplifier because of their power handling capablity, they can't be actively commercialized due to the degradation of current gain occured in hihg current operation. In this paper we analyzed the type of current gain degradation of GaAs HBTs under high constant current stress, and identified the mechanism by using two dimensional numerical simulation. The cause of degradation was found out to be the variation of surface recombination states at the interface between GaAs extrinstic base and the nitride passivating the surface of base. The energy radiated from recombination of carriers in bulk as well as near the surface is estimated to activate the change of the surface states.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1582-1585
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• 2009

The effects of bias stress on spin-coated zinc tin oxide (ZTO) transistors are investigated. Applying a positive bias stress results in the displacement of the transfer curves in the positive direction without changing the field effect mobility or the subthreshold behavior. Device instability appears to be a consequence of the charging and discharging of temporal trap states at the interface and in the zinc tin oxide channel region.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.415-419
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• 2004

Thermal barrier systems are susceptible to instability of the thermally grown oxide(TGO) at the interface between the bond coat(BC) and the thermal barrier coating(TBC). The instabilities have been linked to thermal cycling and initial geometrical imperfections, as well as to misfit strains due to oxide growth and expansion misfit. In this work, deformation of TGO near a surface groove due to thermal cycling has been observed at high temperatures, $1100^{circ}C$, $1150^{circ}C$, $1200^{circ}C$. The effect of peak temperature and the thickness of substrate are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.473-476
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• 1987

Low temperature phosphorus-nitride CVD was newly developed for a high quality gate insulator on InP substrate. This film showed the Poole-Frenkel type conduction in high electric field with resistivity higher than $1{\times}10^{14}$ ohm-cm near the electric field of $1{\times}10^7\;volt/cm$. The C-V hysteresis width was very small as 0.17 volt. The density of interface trap states was $2{\times}10^{11}cm^{-2}ev^{-1}$ below the conduction band edge of InP substrate. Effective electron mobility was about $1200-1500\;cm^2/Vsec$ and showed the instability of PN-InP MISFETs drain current reduced less than 10 percent for the period $0.5-10^3sec$.

• 대한기계학회논문집B
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• 제20권6호
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• pp.1948-1958
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• 1996

Experimental and theoretical studies on the air-assist coaxial atomizer have been continuously carried out for a long time. But now the importance of the theoretical study is tending to increase as with the development of computer. This study is concerned to the spray modelization, especially, the instability of the liquid jet surrounded by the air stream which flows with high velocity. To study the phenomena of the break up, we used the linear theory based on the classical Kelvin-Helmholtz theory for capillary wave at a simple interface and we investigated the variation of liquid core radius. As a result, we obtained that the drop diameter and the variation of the liquid core radius predicted by using our model are reasonable.