• Korean Journal of Food Science and Technology
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• v.48 no.6
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• pp.542-547
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• 2016

The thermal properties of ramie leaf ${\beta}$-amylase (RBA) were examined to develop a novel process for enzyme purification. The thermostability of RBA extract prepared from ramie leaf powder was examined at various temperatures. RBA activity decreased slightly, whereas other carbohydrate-active enzymes, such as $\small{D}$-enzyme, were rapidly inactivated during 30 min incubation at $60^{\circ}C$. When the heat-treated extract was incubated with various substrates, maltose was produced exclusively as the major product, whereas the untreated crude extract produced maltose and other maltooligosaccharides. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, fewer protein bands were observed for the heat-treated extract than the untreated extract, indicating that the thermostable RBA was partially purified and other thermolabile enzymes were eliminated. Thus, the treatment of the RBA extract at $60^{\circ}C$ for 30 min resulted in 5.4-fold purification with a recovery yield of 90%.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.871-874
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• 2005

The effect of rice starch at different concentrations (0, 4, 6, and 8%) on dynamic rheological properties of surimi sols was investigated by small-deformation oscillatory measurements at $10^{\circ}C$ and during heating from 10 to $95^{\circ}C$. Dynamic frequency sweeps at $10^{\circ}C$ showed that the magnitudes of storage modulus (G') decreased with increasing starch concentration while those of tan $\delta$ increased. G' values of surimi-rice starch sols during heating decreased with increasing starch concentration, indicating that the pattern of G' changes during heating was influenced by the concentration of the added rice starch. In general, the characteristic G' thermograms of all samples showed a similar sol-gel transition pattern.

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.26-31
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• 2004

The radiation-induced changes taking place in poly(vinylidene fluoride) (PVDF) exposed to $^{60}Co$ $\gamma-ray$ irradiation were investigated in correlation with the applied doses. Samples were irradiated in air at room temperature by $^{60}Co$ $\gamma-ray$ to doses in the range of 200 to 1000kGy. Various properties of the irradiated PVDF were studied using FTIR, differential scanning calorimetry (DSC), gel fraction and elongation. $^{60}Co\gamma-ray$ irradiation was found to induce changes in chemical, thermal, mechanical and structural properties of PVDF and such changes vary depending on the radiation dose.

• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.269-273
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• 1995

A thermotolerable restriction endonuclease. Svil, found in Streptomyces violochromogenes D2-5 was purified. For the purification, streptomycin sulfate and ammonium sulfate precipitation was used. Ph osphocellulose P-ll, DEAE-Cellulose and Sephacryl-S200 HR colum chromatography were also performed. The purified enzyme was found to be homogeneous and the molecular weight of the enzyme estimated by polyacrylamide gel electrophoresis containing 0.1$%$ SDS was about 32, 000 daltons. The recognition sequence and cleavage site of the enzyme were determined to be $5^1$-$TT\downarrow CGAA$-$3^1$ which is the same sequence as that of Asull. Unlike Asull, however, the Svil shows high thermal stability.

• Bulletin of Food Technology
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• v.7 no.2
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• pp.64-73
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• 1994

Using 20 lipases from various microbial origins medium chain glycerides, namely, mono-, di-, and tri-carproyl glycerols from glycerol and acid were synthesized in isooctane. Enzyme reaction was performed at 0.35 M of capric acid, 0.025M of glycerol and the same mass of silica gel to remove water in 5ml of isooctane with 30mg of lyophilized lipase. Among 20 lipases, eleven lipases showed good synthetic activities, especially lipase from Pseudomonas aeruginosa (Lipase PS), Rhizomucor miehei origined lipase and Chromobacterium viscosum lipase (Lipase CV) showed good activities for production of tricaproylglycerol, while Lipase OF-360 (origined from Candida rugosa) and Lipase D (Rhizopus delemar) were good for production of dicaprolyglycerol. The lipases, especially Lipase PS, have high thermal stability at $ 60^{circ}C$, and optimum pH of lyophilization for dehydrating the lipase was pH 6.5.

• Macromolecular Research
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• v.17 no.9
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• pp.697-702
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• 2009

Mesoporous ethanesilica thin film was prepared using PEO-PLGA-PEO triblock copolymers as structure-directing agents and (1,2-bis(triethoxysilyl) ethane BTESE; bridged organosilicates) as inorganic precursors via one-step sol-gel condensation of ethanesilica precursors. The mesostructure of ethanesilica films is critically dependent on the processing experimental parameters after the hydrolyzed silica sol mixture was spin-cast. This study examined the effects of the block copolymer template/organosilica precursor ratio in the casting solution and aging period before calcination of the mesostructure. It was further demonstrated that mesoscopic ordering of organosilicate thin films is induced by the rearrangement of block copolymer template/organosilica hybrid during thermal decomposition of the PEO-PLGA-PEO triblock copolymer. The mesoporous structure and morphology were characterized by SAXS, TEM and solid-state NMR measurement.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.106-114
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• 1963

The products from polymer pyrolysis at $450^{\circ}$ are cooled with ice, then liquid and gaseous portions are analysed by gas chromatography. Di-2-ethyl hexyl sebacate column, silicone oil column, silica gel column and tetraethyleneglycol dimethylether column, which was most effective for the separation of hydrocarbon gases, are used. Identification of isomers could be secured more effectively by gas chromatography than mass spectrometry. Elucidation of the mechanism for thermal decomposition of polymers could be done through the identification of pyrolysis products. Although more extensive work is needed, some patterns of polymer pyrolysis are discussed.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.964-970
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• 2002

We synthesized three kinds of chromophores incorporating aromatic quinoline unit as a $\pi-conjugated$ bridge in order to prepare more thermally stable nonlinear optical (NLO) chromophores than general stilbene unit. The NLO poly(methylmethacrylate) copolymer, polyimides, and polyester were successfully synthesized by these corresponding quinoline-based monomers. Their physical and optical properties were investigated by thermogravimetry, gel permeation chromatography, ultraviolet-visible spectroscopy, second harmonic generation (SHG) and electro-optic (EO) measurement. All the polymers exhibited better thermal stability,however their NLO activity was a little lower than that of general stilbene-based NLO polymers. Among three kinds of polymers, the PMMA copolymer with quinoline chromophores had the largest SHG coefficient d33 value of 27 pm/V (at 1.064 $\mu\textrm{m})$ and EO coefficient r33 value of 6.8 pm/V (at 1.3 $\mu\textrm{m}$).

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.20-20
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• 2003

A new and simple method has been developed to synthesize highly crystalline and monodisperse maghemite (γ-Fe₂O₃) and zirconia (ZrO₂) nanocristallites. High temperature aging of metal-surfactant complex was founded to generate monodisperse nanoparticles, wherein the nuclei were prepared by the thermal decomposition of iron-oleate complex in case of iron oxide and nonhydrolytic sol-gel reaction in case of zirconia respectively. By varying the experimental conditions, in other words concentration of surfactants, kind of metal precursor, reaction temperature and so on, the diameter of spherical nanoparticles could be controlled at various size. The synthesized nanoparticles were characterized by electron diffraction, X-ray diffraction, and low- and high-resolution transmission electron microscope.

• Journal of Integrative Natural Science
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• v.2 no.2
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• pp.78-81
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• 2009

In recent years, organometallic polymer containing silane and silole unit has been a topic of interest because of the wide range of optical, electrical and luminescent properties. In previous work, we synthesized functionalsilanebridged[1]ferrocenophane from the reaction of dimethyldichlorosilane[Me2SiCl2] and diphenyldichlorosilane[Ph2SiCl2] and dichloromethylvinylsilane[C3H6SiCl2] with ferrocene$[Fe({\eta}-C5H4)2]$ and n-BuLi. In this work, we have synthesized Poly(ferrocenylsilane) via the Thermal Ring-Opening Polymerization(ROP). characteristics of the poly(ferrocenylsilane) were investigated by gel permeation chromatography(GPC), 1H- and 13C-NMR spectroscopy.