• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.207-207
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• 2009

In this work, we report the physical properties of amorphous $Al_2O_3$ thin films by plasma-enhanced chemical vapour deposition (PECVD) using trimethyl-aluminium (TMA) as the Al precursor at low temperatures. The thin films were deposited on Si substrates. The composition and the bonding structure of the amorphous $Al_2O_3$ films were studied using Fourier transform infrared spectroscopy (FT-IR), Ellipsometer and UV-visible Spectrophotometer and MOCON.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.189-194
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• 2001

PDP(Plasma Display Panel)의 투명 유전체에 적용 가능한 저융점 유리 중에서 납성분이 포함 되어 있지 않는 Bi계 유리의 연구를 행하였다. 기판과의 일체화를 위한 유리의 응용으로, 소자와의 반응 억제와 열응력 완화를 위해 유리의 저융점화 및 열팽창 계수를 제어하였다. 본 연구에서 제조된 Bi계 유리는 DTA와 TMA의 열분석을 통해 50$0^{\circ}C$부근에서 연화점이 있고, 7.31~10.02$\times$$10^{-6}$$^{\circ}C$, 비유전을 11.1~13.3, 광투과도가 80%이상으로 PDP 투명유전체에 적용 가능한 Bi계 유리를 얻을 수 있었다.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.143-149
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• 1990

A sol-gel processing of $YBa_2Cu_3O_{7-x}$ superconductor using metal nitrate salts and sodium hydroxide as the starting materials has been investigated because of the need to produce pure, hompgeneous superconducting materials. Since the precipitation of barium hydroxides can be obtained only at high basicities, the process has to be carried out Ca. pH 13 to get the simultaneous coprecipitation with the other metal hydroxides. The involved reaction mechanisms were investigated and intermediate and final products were characterized by means of thermogravimetric analysis(TGA), infra-red(IR) spectroscopy, X-ray diffraction(XRD) analysis, scanning electron microscopy(SEM), thermal mechanical analysis(TMA) and electrical measurement.

• Food Science and Preservation
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• v.6 no.1
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• pp.110-114
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• 1999

In order to study the natural preservation of food, sixteen kinds of medicinal plants were extracted by 80% methanol and then antimicrobial activity of the extracts was investigated against various kinds of microorganisms. The extracts of medicinal plants showed good effects of antimicrobial activity against bacteria except Bacillus cereus, Escherichia coli O-157. Especially, the extracts of Artemisia annua, Aster scaber, Solidago virganrea shower good inhibitory effects on the growth of bacteria to the cooling preservation foods, and Artemisia annua was decreased of the TMA(Trimethylamine) test. the result thus indicate that Artemisia annua, Aster scaber, Solidago fischeri extract inhibitory effects on cooling preservation foods, so that it may be potential as a natural preservatives.

• Journal of the Korean Ceramic Society
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• v.38 no.7
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• pp.628-633
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• 2001

전자 패키징에 적용 가능한 저융점 유리 중에서 납성분이 포함되어 있지 않는 Bi계 유리의 연구를 행하였다. 기판과의 일체화를 위한 유리의 응용으로, 소자와의 반응 억제와 열응력 완화를 위해 유리의 저융점화 및 열팽창계수를 제어하였다. 본 연구에서 제조된 Bi계 유리는 DTA와 TMA의 열분석을 통해 5$50^{\circ}C$ 부근에서 연화점이 있고, 열팽창계수는 7.52~12.09$\times$$10^{-6}$/$^{\circ}C$의 범위였으며, 비유전율은 9~13이었다. 본 연구의 납성분을 포함되어 있지 않는 유리조성은 우수한 내산성을 나타내었다.

• Journal of applied mathematics & informatics
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• v.27 no.1_2
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• pp.59-68
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• 2009

In this paper we present an iterative scheme for finding a common element of the set of zero points of accretive mappings and the set of fixed points of nonexpansive mappings in Banach spaces. By using viscosity approximation methods and under suitable conditions, some strong convergence theorems for approximating to this common elements are proved. The results presented in the paper improve and extend the corresponding results of Kim and Xu [Nonlinear Anal. TMA 61 (2005), 51-60], Xu [J. Math. Anal. Appl., 314 (2006), 631-643] and some others.

• Journal of applied mathematics & informatics
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• v.27 no.1_2
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• pp.13-23
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• 2009

Some strong convergence theorems of explicit iteration scheme for asymptotically nonexpansive semi-groups in Banach spaces are established. The results presented in this paper extend and improve some recent results in [T. Suzuki. On strong convergence to common fixed points of nonexpansive semigroups in Hilbert spaces, Proc. Amer. Math. Soc. 131(2002)2133-2136; H. K. Xu. A strong convergence theorem for contraction semigroups in Banach spaces, Bull. Aust. Math. Soc. 72(2005)371-379; N. Shioji and W. Takahashi. Strong convergence theorems for continuous semigroups in Banach spaces, Math. Japonica. 1(1999)57-66; T. Shimizu and W. Takahashi. Strong convergence to common fixed points of families of nonexpansive mappings, J. Math. Anal. Appl. 211(1997)71-83; N. Shioji and W. Takahashi. Strong convergence theorems for asymptotically nonexpansive mappings in Hilbert spaces, Nonlinear Anal. TMA, 34(1998)87-99; H. K. Xu. Approximations to fixed points of contraction semigroups in Hilbert space, Numer. Funct. Anal. Optim. 19(1998), 157-163.]

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.470-473
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• 2010

Graphene, consisting of a single layer of carbon in a two-dimensional lattice, has been emerging as a fascinating material with many unique physical, chemical and mechanical properties. In this study, graphenes were prepared by a chemical method. To develop high performance polymer nanocomposites reinforced by graphenes, adequate dispersion of the fillers and strong interfacial bonding between the fillers and the polymer matrix are essential. The purpose of this study was to examine the influence of introducing amine groups on the surfaces of graphenes. FT-IR spectroscopy, SEM were used to confirm the functionalization. Epoxy nanocomposites comprising the graphenes were prepared and their characteristics were investigated by DSC, DMA and TMA. Fracture surfaces of the nanocomposites were investigated by SEM. The functionalized graphenes induced strong interfacial bonding than the pristine graphenes and resulted in considerable improvements in the performance of the nanocomposites.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.104-107
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• 2005

COMS(Communication, Ocean, and Meteorological Satellite) is the geostationary satellite for the mission of satellite communication, ocean monitoring, and meteorological service. It is scheduled to be launched at the end of 2008. Ocean payload of COMS named as GOCI(Geostationary Ocean Color Imager) observes ocean color and derives the chlorophyll concentrlition, the concentration of dissolved organic material and so on. In operational oceanography, satellite derived data products are used to provide forecasting and now casting of the ocean and coastal water state. In this work, conceptual design of structural part of GOCI is carried out and two baseline concepts are proposed. The one is dioptric module that uses lens system and the other is TMA(Three Mirror Anastigmat) module that uses mirror system. Trade-off studies between two concepts are investigated by considering optical and mechanical performances. Finally, on-going tasks and future development plan are briefly discussed.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.195-195
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• 2003

PDP, FED 등의 디스플레이와 각종 IC 칩부품에 적용 가능한 저융점 유리 프릿 중에서 환경규제가 이루어지고 있는 납성분이 포함되어 있지 않은, Bi계 유리 프릿의 열적 거동 연구를 행하였다. 열처리 온도에 따른 열거동에 따라 프릿의 소성온도 및 미세구조가 결정되므로, 열처리 온도에 따른 유리 프릿의 젖음각을 측정하였고, DTA와 TMA를 통해 유리전이온도, 연화점, 열팽창계수 변화 경향성을 관찰하였다. 본 연구에서 제조된 유리는 조성에 따라 전이온도가 390-50$0^{\circ}C$, 연화점이 400-55$0^{\circ}C$, 열팽창계수가 65-120$\times$10-7/$^{\circ}C$ 범위를 나타내었으며, 고온현미경 측정 결과 Pb-계 유리와 비교시 유사한 열거동을 나타내었다.