• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.250-256
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• 2014

In this study, we deposited and investigated ${\mu}c$-Si:H thin films prepared by Plasma Enhanced Chemical Vapor Deposition(PECVD) system. To deposition silicon thin films, we controlled $SiH_4$ gas concentration, RF input power, and heater temperature. According to the experiments, the more $SiH_4$ gas concentration increased, deposition rate also increased but crystalline property decreased at the same conditions. In the RF input power case, deposition rate and crystalline property increased together when the input power increased from 100[W] to 300[W]. If RF input power was 300[W], deposition rate has reached saturation point. In the heater temperature, deposition rate increased when heater temperature increased. Crystalline property maintained a certain level until heater temperature was $250[^{\circ}C]$. And then it was a suddenly increased. Multistep method has been proposed to improve the quality of ${\mu}c$-Si:H thin film. $SiH_4$ gas was injected with a time interval. According to the experiments, crystallite ratio improve about 20~60[%] and photo conductivity increased up to six times.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.58-62
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• 1998

In the industrial motor drive systems, a torsional vibration is often generated because of the elastic elements in torque transmission. One of general methods for the system is H$\infty$ controller to suppress the torsional vibration and reject the torque disturbance. vibration and reject the torque disturbance. Moreover, the two-degrees-of-freedom controller, which includes the H$\infty$ controller, is designed in order to improve the command following property. In this paper, we propose a new H$\infty$ controller with partial state feedback. This method having simple structure satisfies with the fast command following property and the attenuation of disturbances and vibrations simultaneously, just like the complicated TDOF H$\infty$ controller

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.576-578
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• 2000

This paper address the prediction method of a soil thermal property depending on soil moisture contents and suggests the guideline to determine the soil thermal resistivity for the calculation of the cuurent carrying capacity of underground power cables in Korea.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.529-534
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• 2005

In this paper, a new type of output feedback control, called a $H_2/H_{\infty}$ fnite memory control (FMC), is proposed for deterministic state space systems. Constraints such as linearity, unbiasedness property, and finite memory structure with respect to an input and an output are required in advance to design $H_2/H_{\infty}$ FMC in addition to the performance criteria in both $H_2$ and $H_{\infty}$ sense. It is shown that $H_2$, $H_{\infty}$, and mixed $H_2/H_{\infty}$ FMC design problems can be converted into convex programming problems written in terms of linear matrix inequalities (LMIs) with some linear equality constraints. Through simulation study, it is illustrated that the proposed $H_2/H_{\infty}$ FMC is more robust against uncertainties and faster in convergence than the existing $H_2/H_{\infty}$ output feedback control schemes.

• Bulletin of the Korean Mathematical Society
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• v.45 no.1
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• pp.59-66
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• 2008

Keskin and Harmanci defined the family B(M,X) = ${A{\leq}M|{\exists}Y{\leq}X,{\exists}f{\in}Hom_R(M,X/Y),\;Ker\;f/A{\ll}M/A}$. And Orhan and Keskin generalized projective modules via the class B(M, X). In this note we introduce X-local summands and X-hollow modules via the class B(M, X). Let R be a right perfect ring and let M be an X-lifting module. We prove that if every co-closed submodule of any projective module P contains Rad(P), then M has an indecomposable decomposition. This result is a generalization of Kuratomi and Chang's result [9, Theorem 3.4]. Let X be an R-module. We also prove that for an X-hollow module H such that every non-zero direct summand K of H with $K{\in}B$(H, X), if $H{\oplus}H$ has the internal exchange property, then H has a local endomorphism ring.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.5-11
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• 2008

To study the effects of $H_2$ gas on AIN insulation thin film, we prepared AIN thin film on Si and GaAs substrate by means of reactive sputtering method using $H_2$ gas as an additives, With treatment conditions of $H_2$ gas AIN thin film shows variable electrical properties such as its crystallization and hysterisis affected to electrical property, As a results, AIN thin film fabricated on Si substrate post-treated with $H_2$ gas for 20 minutes shows much better an insulation property than that of pre-treated, And AIN film treated with $H_2$ gas comparing to non-treated AIN film shows a flat band voltage decreasment. But In GaAs substrate $H_2$ gas does not effect on the flat band voltage.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.350-356
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• 1990

Functional properties such as nitrogen solubility, emulsifying property, foaming property, and water and oil absorption of sesame and perilla protein isolates were determined at pH range of 2-10 and ionic strength of 0-0.5M NaCl. Nitrogen solubility of protein isolates in distilled water showed minimum value at pH6.0 in sesame and at pH 4.0 in perilla and soybean protein isolates, and significantly increased above pH 8.0 in all samples. Addition of 0.1M NaCl solution increased nitrogen solubility, however, decreased in 0.5M NaCl solution. Emulsion activities of all the protein isolates showed minimum value at pH 4.0 and increased in 0.1M NaCl solutions while it was reduced in 0.5M NaCl solutions. The perilla protein isolate showed higher emulsion activity than that of soybean and sesame protein isolates at above pH 6.0. Foaming capacities of sesame and perilla protein isolates were lower than soybean protein isolate and generally all of the samples showed higher profiles in NaCl solutions. The foaming stability of soybean isolate decreased abruptly in 10min, while it was slowly decreased for sesame and perilla isolates during initial 30 min. Oil absorption capacity of perilla protein isolate was higher than that of sesame and soybean protein isolates. Water absorption capacity was similar among the three samples studied.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.31-35
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• 2002

It is hard to expect excellent electrical, mechanical and chemical properties from most of the composite materials presently used as insulators due to insufficient wettability property caused by the difference of interfacial properties between the matrix material and the reinforcer. Therefore, various interfacial coupling agents have been developed to improve the interfacial properties of composite materials. But if the wettable coupling agents are used outdoor for a long time, change in quality takes place in the coupling agents themselves, bringing about deterioration of the properties of the composite materials. In this study, composite materials were put to dry interfacial treatment by use of plasma technology. It has been presented that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system pressure, 100 W of discharge power, and 3 minutes of discharge time. Also, the surface resistance rate and dielectric property were improved.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.295-298
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• 2005

This paper is concerned with the precision material property measurement of a micro metal thin foil that is used in MEMS technology. Since these MEMS components require great precision and accuracy, evaluation of reliability such as the lift cycle endurance test, impact test, and residual stress test is necessary for these components. However, in practice, real reliability tests are not easy to perform due to consideration of various factors. Rather than actual testing, it would be much easier to evaluate the reliability of components by the analytical approach. Although the analytical method is utilized by software tools, it is obviously necessary to acquire fundamental properties of materials through real test methods. In this paper, the oriented mechanical properties of aluminum thin foil are measured by nano scale material property measurement system.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.250-252
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• 2003

This paper is the estimation of the thermal property for the backfill materials according to the experimental measurements both a laboratory and field test.