• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.120-120
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• 1998

Boron nitride (BN) films have attracted a growing interest for a variety of t technological applications due to their excellent characteristics, namely hardness, c chemical inertness, and dielectrical behavior, etc. There are two crystalline phases 1551; of BN that are analogous to phases of carbon. Hexagonal boron nitride (h-BN) has a a layered s$\sigma$ucture which is spz-bonded structure similar to that of graphite, and is t the stable ordered phase at ambient conditions. Cubic boron nitride (c-BN) has a z zinc blende structure with sp3-bonding like as diamond, 따ld is the metastable phase a at ambient conditions. Among of their prototypes, especially 삼Ie c-BN is an i interesting material because it has almost the same hardness and thermal c conductivity as di없nond. C Conventionally, significant progress has been made in the experimental t techniques for synthesizing BN films using various of the physical vapor deposition 밍ld chemical vapor deposition. But, the major disadvantage of c-BN films is that t they are much more difficult to synthesize than h-BN films due to its narrow s stability phase region, high compression stress, and problem of nitrogen source c control. Recent studies of the metalorganic chemical vapor deposition (MOCVD) of I III - V compound have established that a molecular level understanding of the d deposition process is mandatory in controlling the selectivity parameters. This led t to the concept of using a single source organometallic precursor, having the c constituent elements in stoichiometric ratio, for MOCVD growth of 삼Ie required b binary compound. I In this study, therefore, we have been carried out the growth of h-BN thin f films on silicon substrates using a single source precursors. Polycrystalline h-BN t thin films were deposited on silicon in the temperature range of $\alpha$)() - 900 $^{\circ}$C from t the organometallic precursors of Boron-Triethylamine complex, (CZHs)3N:BRJ, and T Tris(dimethylamino)Borane, [CH3}zNhB, by supersonic molecular jet and remote p plasma assisted MOCVD. Hydrogen was used as carrier gas, and additional nitrogen w was supplied by either aDlIDonia through a nozzle, or nitrogen via a remote plasma. T The as-grown films were characterized by Fourier transform infrared spectroscopy, x x-ray pthotoelectron spectroscopy, Auger electron spectroscopy, x-ray diffraction, t transmission electron diffraction, optical transmission, and atomic force microscopy.roscopy.

• Korean Journal of Optics and Photonics
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• v.16 no.6
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• pp.535-541
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• 2005

We report on the development of a passively mode-locked near-infrared femtosecond laser with Cr:YAG crystal that operates near room temperature. The laser wavelength could easily be tuned by using only the internal prism pair over 110 nm from 1400 nm to 1510 nm in cw and over about 30 nm in mode-locked operation, respectively Maximum cw output powers of 810 mW were obtained with $1.5 \%$ output coupler for absorbed pump powers of 7.6 W. For compensation of the internal group velocity dispersion, an IR graded prism pair was used. The Cr:YAG laser delivered nearly Fourier-transform limited pulses with a pulse duration as short as 64 fs at 100 MHz repetition rate. In the mode-locked regime, the laser was operating at 1510 nm with a spectral bandwidth of 44 nm. In order to avoid unstable mode-locking and power instabilities, self-built tubes were inserted into the beam path in the resonator and purged with N2 gas. Finally, output powers of the Cr:YAG laser were optimized to 250 mW fer long time stable mode-locked operation.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.581-588
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• 2007

To enhance the photodecomposition of concentrated ammonia into N2, Pt/V-TiO2 photocatalysts were prepared using solvothermal and impregnation methods. Nanometer-sized particles of 0.1, 0.5 and 1.0 mol% V-TiO2 were prepared solvothermally, and then impregnated with 1.0 wt% Pt. The X-ray diffraction (XRD) peaks assigned to V2O5 at 30.20 (010) and Pt metal at 39.80 (111) and 46.20 (200) were seen in the 1.0 wt% Pt/ 10.0 mol% V-TiO2. The particle size increased in the order: pure TiO2, V-TiO2 and Pt/V-TiO2 after thermal treatment at 500 °C, while their surface areas were in the reverse order. On X-ray photoelectron spectroscopy (XPS), the bands assigned to the Ti2p3/2 and Ti2p1/2 of Ti4+-O were seen in all the photocatalysts, and the binding energies increased in the order: TiO2 < Pt/V-TiO2 < V-TiO2. The XPS bands assigned to the V2p3/2 (517.85, 519.35, and 520.55 eV) and V2p1/2 (524.90 eV) in the V3+, V4+ and V5+ oxides appeared over V-TiO2, respectively, while the band shifted to a lower binding energy with Pt impregnation. The Pt components of Pt/ V-TiO2 were identified at 71.60, 73.80, 75.00 and 76.90 eV, which were assigned to metallic Pt 4f7/2, PtO 4f7/2, PtO2 4f7/2, and PtO 4f5/2, respectively. The UV-visible absorption band shifted closer towards the visible region of the spectrum in V-TiO2 than in pure TiO2 and; surprisingly, the Pt/V-TiO2 absorbed at all wavelengths from 200 to 800 nm. The addition of vanadium generated a new acid site in the framework of TiO2, and the medium acidic site increased with Pt impregnation. The NH3 decomposition increased with the amount of vanadium compared to pure TiO2, and was enhanced with Pt impregnation. NH3 decomposition of 100% was attained over 1.0 wt% Pt/1.0 mol% V-TiO2 after 80 min under illumination with 365 nm light, although about 10% of the ammonia was converted into undesirable NO2 and NO. Various intermediates, such as NO2, -NH2, -NH and NO, were also identified in the Fourier transform infrared (FT-IR) spectra. From the gas chromatography (GC), FT-IR and GC/mass spectroscopy (GC/MS) analyses, partially oxidized NO and NO2 were found to predominate over V-TiO2 and pure TiO2, respectively, while both molecules were reduced over Pt/V-TiO2.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.444-450
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• 2013

A Gram-negative, strictly aerobic, non-motile, non-spore-forming, and rod-shaped bacterial strain designated FW-$6^T$ was isolated from a freshwater sample and its taxonomic position was investigated by using a polyphasic approach. Strain FW-$6^T$ grew optimally at $10-42^{\circ}C$ and at pH 7.0 on nutrient and R2A agar. Strain FW-$6^T$ displayed ${\beta}$-glucosidase activity that was responsible for its ability to transform ginsenoside $Rb_1$ (one of the dominant active components of ginseng) to Rd. On the basis of 16S rRNA gene sequence similarity, strain FW-$6^T$ was shown to belong to the family Sphingomonadaceae and was related to Novosphingobium aromaticivorans DSM $12444^T$ (98.1% sequence similarity) and N. subterraneum IFO $16086^T$ (98.0%). The G+C content of the genomic DNA was 64.4%. The major menaquinone was Q-10 and the major fatty acids were summed feature 7 (comprising $C_{18:1}{\omega}9c/{\omega}12t/{\omega}7c$), summed feature 4 (comprising $C_{16:1}{\omega}7c/iso-C_{15:0}2OH$), $C_{16:0}$, and $C_{14:0}$ 2OH. DNA and chemotaxonomic data supported the affiliation of strain FW-$6^T$ to the genus Novosphingobium. Strain FW-$6^T$ could be differentiated genotypically and phenotypically from the recognized species of the genus Novosphingobium. The isolate that has ginsenoside converting ability therefore represents a novel species, for which the name Novosphingobium ginsenosidimutans sp. nov. is proposed, with the type strain FW-$6^T$ (= KACC $16615^T$ = JCM $18202^T$).

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1249-1256
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• 2017

In our search for new sources of bioactive secondary metabolites from Streptomyces sp., the ethyl acetate extracts from endophytic Streptomyces SUK 25 afforded five active diketopiperazine (DKP) compounds. The aim of this study was to characterize the bioactive compounds isolated from endophytic Streptomyces SUK 25 and evaluate their bioactivity against multiple drug resistance (MDR) bacteria such as Enterococcus raffinosus, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter spp., and their cytotoxic activities against the human hepatoma (HepaRG) cell line. The production of secondary metabolites by this strain was optimized through Thornton's medium. Isolation, purification, and identification of the bioactive compounds were carried out using high-performance liquid chromatography, high-resolution mass liquid chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, and cryopreserved HepaRG cells were selected to test the cytotoxicity. The results showed that endophytic Streptomyces SUK 25 produces four active DKP compounds and an acetamide derivative, which were elucidated as $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Leu-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Phe-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Phe)$, and N-(7-hydroxy-6-methyl-octyl)-acetamide. These active compounds exhibited activity against methicillin-resistant S. aureus ATCC 43300 and Enterococcus raffinosus, with low toxicity against human hepatoma HepaRG cells. Endophytic Streptomyces SUK 25 has the ability to produce DKP derivatives biologically active against some MDR bacteria with relatively low toxicity against HepaRG cells line.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.608-615
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• 2017

The objective of this study was to evaluate the physicochemical, structural, and rheological properties of new domestic potato cultivars ('Goun', 'Sebong', and 'Jinsun') against the foreign potato cultivar 'Atlantic'. Based on the results obtained from scanning electron micrograph, X-ray, and Fourier transform infrared spectrum analyses, the structural properties of all potato flours were not considerably different. Rapid visco analyzer analyses showed that the setback viscosities of 'Goun', 'Sebong', and 'Jinsun' were significantly lower than that of 'Atlantic'. For steady shear rheological properties, potato flour dispersions showed shear-thinning behaviors (n=0.45~0.49) at $25^{\circ}C$. Apparent viscosity and consistency index of 'Atlantic' were similar to those of 'Sebong' and 'Jinsun'. For dynamic shear rheological properties, storage modulus (G′) and loss modulus increased, whereas complex viscosity (${\eta}^*$) was reduced with increasing frequency from 0.63 to 62.8 rad/s. G′ and ${\eta}^*$ values of 'Jinsun' were significantly higher than those of the other potato cultivars.

• Archives of design research
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• v.12 no.4
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• pp.327-337
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• 1999

As the computer technology grows so fast, it can affect the human life in every fields. Specially, advent of Digital epoch is changing human life completely. In the past, people should get the information through the mass-media. But these days we can produce and provide some information through new media, Internet. In other words, two-ways communication like internet make individual be the producer in the information stream. Especially, net generation is different form the old generation and they want to express themselves distinctively from others. Nevertheless, they can't have the chance to express their identity properly and only they try to satisfy their needs by consuming special goods. In this article, I want to suggest a program that an individual can express their own identity and image. I will transform CIP (Corporate Information Program) and adjust it to an individual case. This is different from the previous study that emphasize the external factor figure, etc. First, we will find the MI(mind identity) and the BI(behavior identity). Second, we will present the VI(visual identity) by using two factors. - MI, VI. Finally, we will analyze them totally and make the PI(personal identity ) that can express their own identity and philosophy well. Through this programs, they can express themselves well and get the chance to think creatively. I am sure this program will have more implications about image strategy.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.546-553
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• 2012

Urushiol extracted from lacquer tree exhibits good thermal stabilities as well as antimicrobial andantioxidant properties. However, it has been known that the urushiol derivates bring out allergy. In this study, polyurushiol (PUOH) powders were successfully synthesized for the safe and convenient handling of allergic urushiol. First, the as-synthesized PUOH was confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermal gravimetric analyzer (TGA), antioxidant test and antimicrobial test. And then, six different LDPE/PUOH composite films were prepared via a twin screw extruder system and investigated their feasibility to use as active packaging materials. Their chemical structures, morphology, thermal optical and antimicrobial properties of the LDPE/PUOH composite films were investigated as a function of PUOH contents. FTIR and SEM results showed that LDPE/PUOH composite films have a weak interfacial interaction and poor dispersion with a high PUOH loading. The thermal properties increased up to 3 wt% as the content of PUOH increases. Compared to the pure LDPE films, LDPE/PUOH composite films are more effective in the UV absorbance and antibacterial activity against E. coli. To maximize the performance of LDPE/PUOH compositefilms as the packaging materials, further researches are required to enhance the dispersion of PUOH powders in the LDPE matrix.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.360-368
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• 2017

The objective of this research was to elucidate the physicochemical, structural, pasting and rheological properties of potato starch isolated from a foreign potato cultivar ('Atlantic') and new domestic potato cultivars ('Goun', 'Sebong', and 'Jinsun'). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and one-dimensional nuclear magnetic resonance (1D NMR) showed that the structural properties of potato starch did not vary significantly with cultivars. RVA analysis demonstrated that the 'Atlantic' starch had the highest breakdown viscosity among all potato starches. In steady shear rheological analysis, all potato starch dispersions showed shear-thinning behaviors (n =0.63-0.72) at $25^{\circ}C$. The highest apparent viscosity (${\eta}_{a,5}$), consistency index (K), and yield stress (${\sigma}_{oc}$) were observed in the 'Goun' starch dispersion. In dynamic shear rheological analysis, storage modulus (G') and loss modulus (G") values of new domestic potato starch dispersions were higher than those of the 'Atlantic' starch dispersion.

• Journal of the Korean Institute of Gas
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• v.2 no.4
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• pp.18-24
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• 1998

Polyurethane (PU) synthesized from 4,4'-diphenylmethane diisocyanate having high functionality (f=2.9) and polyester polyol have been investigated by differential scanning calorimeter (DSC), dynamic mechanical thermal analyzer (DMTA), and Fourier transform infrared spectroscope (FT-IR). From the DSC measurement of polyurethane, a single transition temperature ($T_g$) was observed. This result indicates that polyurethanes synthesized in this work have homogeneous network structure due to high functionality of diisocyanate. It was also found that the $T_g$ of polyurethane was increased as hard segment content was increased. The results from DMTA measurement are consistent with DSC results. In order to investigate the effect of thermal annealing on the $T_g$ of polyurethane, the samples were annealed at various annealing conditions. $T_gs$ of polyurethanes were found to increased with annealing temperature. From swelling experiment and FT-IR studies, it was found that the $T_g$ was increased as crosslinking density of polyurethane was increased.