• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.991-994
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• 2007

In this paper, we have designed the anti-reflection(AR) coating for $1400{\sim}1600$ nm wavelength range on the ferrule facet of optical connector. The low-temperature ion-assisted deposition was applied to AR coating on the ferrule facet in order to avoid damage of optical connector. We have measured the refractive index of coating film($Ta_2O_5\;and\;SiO_2$) using the ellipsometer and optimized the film thickness using the SEM and thickness measurement equipment. UV-VIS-NIR spectrophotometer is used to measure transmissivity of the AR coated ferrule facet. The refractive index of $Ta_2O_5\;and\;SiO_2$ is $2.123{\sim}2.125$ and $1.44{\sim}1.442$, respectively, for $1400{\sim}1600$ nm wavelength range. The transmissivity of the AR coated ferule facet is more than 99.8 % for $1425{\sim}1575$ nm wavelength range and more than 99.5 % for $1400{\sim}1600$ nm wavelength range. The return loss of the AR coated ferrule facet is 30.1 dB.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.315-320
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• 2000

We have investigated the crystal structure and electrical properties of Pt/SBT/$ZrO_2$/Si (MFIS) and Pt/SBT/Si (MFS) structures for the gate oxide of ferroelectric memory. XRD spectra and SEM showed that the SBT film of SBT/$ZrO_2$/Si structure had larger grain than that of SBT/Si structure. $ZrO_2$ film between SBT film and Si substrate is confirmed as a good candidate for a diffusion barrier by the analysis of AES. The remanent polarization decreased and coercive voltage increased in Pt/SBT/$ZrO_2$/Pt/$SiO_2$/Si structure. This effect may increase memory window of MFIS structure directly related to the coercive voltage. From the capacitance-volt-age characteristics, the memory windows of Pt/SBT (210 nm)/$ZrO_2$ (28 nm)/Si structure were in the range of 1~l.5 V at the applied voltage of 4~6 V. The current densities of Pt/SBT/ZrO$_2$/Si with as -deposited Pt electrode and annealed at $800^{\circ}C$ in $O_2$ambient were $8\times10^{-8} A/\textrm{cm}^2$ and $4\times10^{-8}A/\textrm{cm}^2$ , respectively.

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.189-195
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• 2001

We prepared TMR junctions of NiFe(170 )/CoFe(48 )/Al(13 )-O/CoFe(500 )/Ta(50 ) structure on 2.5$\times$2.5 $\textrm{cm}^2$ area Si/SiO$_2$ substrates in order to investigate the uniformity of magnetoresistance(MR) value using a ICP magnetron sputter. Each layer was deposited by the ICP magnetron sputter and tunnel barrier was formed by the plasma oxidation method. We measured MR ratio and resistance of TMR devices with four-terminal probe system by applying external magnetic field. Although we used ICP sputter which is known as superior to make uniform films, the standard variation of MR ratio was 2.72. The variation was not dependent on the TMR devices location of a substrate. We found that MR ratio and spin-flip field (H's) increased as the resistance increased, which may be caused by local interface irregularity of the insulating layer. The variation of resistance value was 64.19 and MR ratio was 2.72, respectively. Our results imply that to improve the insulating layer fabrication process including annealing process to lessen interface modulation in order to mass produce the TMR devices.

• Food Science and Preservation
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• v.5 no.4
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• pp.386-391
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• 1998

Lactobacillus plantarum KLAB21 isolated from kimchi has been shown to produce antimutagenic subtance(s) into the culture medium using Salmonella typhimurium TA100 and S. typhimurium TA98 (Rhee and Park, Korean J. Appl. Microbiol.. Biotechnol., 1999, in press). In this study, the effects of culture conditions were investigated to maximize the production of antimutagenic substance(s) against 4-nitro-O-phenylenediamine(NPD) by the strain KLAB21. Glucose(255) as a carbon source and yeast extract or bactopeptone(1%) as a nitrogen source showed the highest production of the antimutagenic substance(s). Optimal initial pH of the culture medium, culture temperature and shaking speed for the antimutagenic substance(s) production were pH 7.0, 37$^{\circ}C$ and 150rpm, respectively. Under the optimal conditions, the antimutagenic activity of L. plantarum KLAB21 culture supernatant against NPD on Salmonella typhimurium TA100 and S. typhimurium TA98 were 73.95% and 59.74%, respectively.

• KSBB Journal
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• v.18 no.4
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• pp.324-328
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• 2003

In a mutagenicity test using the Salmonella typhimurium TA98 and TA100, the Xanthium strumarium L. extracts had not a mutagenicity. The extracts were assayed that antioxidative effect using a colony formation assay. The extracts showed protective effects against the cytotoxicity of H$_2$O$_2$ and increased the immunity induced by TNF and IL-1${\beta}$. The modulating effect of Xanthium strumarium L. extract on the induction of carcinogenesis by N-methyl-N'-nitro-N-nitrosoguanidin (MNNG), was investigated in Wistar rats. The GSH content was found to be reduced by MNNG treatment, but increased on adding extract. In addition the Xanthium strumarium L. extract increased p53 expression versus MNNG alone.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.11a
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• pp.32-32
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• 2003

• Proceedings of the Korean Vacuum Society Conference
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• 1995.02a
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• pp.047-48
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• 1995

• Proceedings of the Korean Vacuum Society Conference
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• 1995.02a
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• pp.049-50
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• 1995

• Proceedings of the Korean Vacuum Society Conference
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• 1993.02a
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• pp.90-91
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• 1993

• Proceedings of the Korean Vacuum Society Conference
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• 1994.06a
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• pp.90-91
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• 1994