• Korean Journal of Materials Research
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• v.21 no.2
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• pp.111-114
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• 2011

As a growth-template of ZnO nanorods (NR), a hexagonal $\beta-Ni(OH)_2$ nanosheet (NS) was synthesized with the low temperature hydrothermal process and its microstructure was investigated using a high resolution scanning electron microscope and transmission electron microscope. Zinc nitrate hexahydrate was hydrolyzed by hexamethylenetetramine with the same mole ratio and various temperatures, growth times and total concentrations. The optimum hydrothermal processing condition for the best crystallinity of hexagonal $\beta-Ni(OH)_2$ NS was determined to be with 3.5 mM at $95^{\circ}C$ for 2 h. The prepared $Ni(OH)_2$ NSs were two dimensionally arrayed on a substrate using an air-water interface tapping method, and the quality of the array was evaluated using an X-ray diffractometer. Because of the similarity of the lattice parameter of the (0001) plane between ZnO (wurzite a = 0.325 nm, c = 0.521 nm) and hexagonal $\beta-Ni(OH)_2$ (brucite a = 0.313 nm, c = 0.461 nm) on the synthesized hexagonal $\beta-Ni(OH)_2$ NS, ZnO NRs were successfully grown without seeds. At 35 mM of divalent Zn ion, the entire hexagonal $\beta-Ni(OH)_2$ NSs were covered with ZnO NRs, and this result implies the possibility that ZnO NR can be grown epitaxially on hexagonal $\beta-Ni(OH)_2$ NS by a soluble process. After the thermal annealing process, $\beta-Ni(OH)_2$ changed into NiO, which has the property of a p-type semiconductor, and then ZnO and NiO formed a p-n junction for a large area light emitting diode.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.227-236
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• 1995

The objective of this research was to characterize fucoidans isolated from Laminaria religiosa and Undaria pinnatifida in Korea to obtain basic data for Production of soluble dietary fiber materials with biological functionality. Fucoidans were successively extracted 3 times at $65\%$ for 1hr with arid solution of pH 2.0, and cetylpyridinium chloride was used for partial purification. The yields of partially purified fucoidans were $2.71\%$ for L. religiosa, $6.65\%$ for sporophylls of U. pinnatifida and $0.40\%$ for blade of U. pinnatifida. The yield from sporophylls of U. pinnatifida was highest among the sample tested, whereas the yield from blade of U. pinnatifida was lowest. It appeared that the fuconidans content in different parts of U. pinnatifida varied. Partially purified fucoidans were separated into 3 fractions by DEAE-Sephadex A-25 ion exchange column and the maior fractions were refractionated with tractional precipitation with ethanol. $60-70\%$ ethanol precipitated fractions of 1. religiosa and sporophylls of U. pinnatifida turned out to be homogeneous by cellulose acetate electrophoresis and gel filteration chromatography. The molar ratios of fucose, galactose, and sulfate in the purified fucoidans(ethanol precipitated fractions) were 1 : 0.31 : 2.43 for L. religiosa and 1 : 0.97 : 1.99 for sporophylls of U. pinnatifida. The averaged molecular weights of the purified fucoidans from L. religiosa and sporophylls of U. pinnatifida were 31,000 and 38,000, respectively.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.743-753
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• 2014

The number concentrations and the water soluble ionic concentrations of $PM_{2.5}$ have measured at Gosan site in Jeju, Korea, from March 2010 to December 2010, to clarify their characteristics. $PM_{2.5}$ number concentrations vary from 22.57 to $975.65particles/cm^3$ with an average value of $240.41particles/cm^3$, which have been recorded evidently high in spring season as compared with those in other season. And the concentrations in small size ranges are greatly higher than those in large size ranges, so the number concentration in the size range $0.25{\sim}0.45{\mu}m$ has more than 94% of the total number concentration of $PM_{2.5}$. The major ionic components in $PM_{2.5}$ are $SO{_4}^{2-}$, $NH_4{^+}$ and $NO_3{^-}$, which are mainly originated from anthropogenic sources, on the other hand, the concentrations of $Cl^-$, $K^+$, $Ca^{2+}$ and $Mg^{2+}$ are recorded relatively lower levels. The concentrations of the major ionic components are very high in spring season, but the concentration levels of the other components are recorded significantly high in winter season. On the other hand, in summer season, the lowest concentration levels are observed for overall components as well as the sum of them. The concentration ratios of nss-$SO{_4}^{2-}/SO{_4}^{2-}$ and nss-$Ca^{2+}/Ca^{2+}$ are 98.1% and 88.9%. And the concentration ratio of $SO{_4}^{2-}/NO_3{^-}$(3.64) is greatly higher than the value in urban area due to no large $NO_x$ emission sources in the measurement. In addition, the correlation and the factor analysis for the number and the ionic concentrations of $PM_{2.5}$ are performed to identify their sources. From the Pearson correlation analysis and the factor analysis, it can be suggested that the smaller parts(< $0.5{\mu}m$) of $PM_{2.5}$ is contributed by anthropogenic sources, but the sources of the remaining larger parts of $PM_{2.5}$ are not able to be specified sources in this study.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.495-510
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• 2017

This study was to investigate the antioxidant activities of Cryptomeria japonica leaves extracts such as essential oil, methanol extract and hot water extract and to evaluate its potential as a natural antioxidant. Antioxidant activities of extracts were evaluated by DPPH radical scavenging activity, FRAP activity, zanthin oxidase inhibitory activity, and iron ion chelate activity, comparing with the positive controls. According to the results, methanol and hot water extracts showed higher antioxidant activities than essential oil. This fact suggested that terpenoids have lower antioxidant effect than phenolic compounds which were found in methanol and hot water extracts. Especially, acetone and water soluble fractions of methanol extract and ethanol fraction of hot water extract contained a lot of phenolic compounds and hydroxyl group, indicating that many hydroxyl groups and glycosidic bonds showed higher antioxidant effect than the other fractions. These results can suggest that the phenolic compounds which contained hydroxyl group or glycosidic bonds have a certain role for effective antioxidant activities.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.362-367
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• 2006

Waste activated sludge(WAS) collected from domestic wastewater treatment plant is biomass that contains large quantities of organic matter. However, relevant literature show that the bio-hydrogen yield using WAS was too low. In this study, the effect of pretreatment of WAS on hydrogen yield was investigated. Pretreatment includes acid and alkali treatments, grinding, heating, ozone and ultrasound methods. After pretreatment organic matters of WAS were solubilized and soluble chemical oxygen demand(SCOD) was increased by 14.6 times. Batch experiments were conducted to investigate the effects of pre-treatment methods and buffer solution, hydrogen partial pressure, and sodium ion on hydrogen production from WAS by using heated anaerobic mixed cultures. Experimental results showed that addition of buffer solution, efficient pre-treatment method with alkali solution, and gas sparging condition markedly increased the hydrogen yield to 0.52 mmol $H_2/g$-DS.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.675-687
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• 2005

In this study, the cyclone/denuder/filter pack sampling system was used to measure the daily concentrations of water soluble inorganic compounds of fine ($D_{p}< 2.5\;{\mu}m$) and coarse ($D_{p}<10{\mu}m$m) size fractions of aerosol and related gases at Gosan super site during ABC-EAREX 2005. The mean concentrations for $HNO_{3},\;HNO_{2},\;NH_{3}$, were 0.39, 0.08, and $0.29\;{\mu}g/m^3$. respectively. Average concentrations of sulfate, nitrate, and ammonium in $PM_{2.5}$ were 3.39, 1.06, and $1.04\;{\mu}g/m^3$, which occupied about $26\%$ of total $PM_{2.5}$ mass. In particular, more than half of these ionic species were found in size of less than $2.5\;{\mu}m$. Gas phase nitric acid concentrations have shown high correlation coefficient with $HNO_{2}$(R=0.80) and $O_{3}$(R=0.78), implying the active photochemical reactions from its precursors. Equivalent molar ratios between major ion components, $NH_{4}\;^{+}/nss\;SO_4\;^{2-},(0.83\;for\;PM_{2.5},\;0.86\;for\;PM_{10})$, revealed that the existing forms of the secondary aerosols were probably $(NH_{4})_{2}SO_{4}\;and\;(NH_{4})_{3}H\;(SO_{4})_{2}$. Especially, $(NH_{4}\;^{+}+K^{+}+Ca^{2+}+Mg^{2+})/(NO_{3}\;^{-}+nss\;SO_{4}\;^{2-}) (0.99\;for\;PM_{2.5},\;1.05\;for\;PM_{10})$ indicated that some of them existed not only as $NH_{4}NO_{3}$ but also as $CaSO_{4}\;or\;KNO_{3}$, which pointed out the probability of influences from the abundant soil components during Asian dust (AD) periods. These neutralized types of secondary aerosols showed that pollutants could be aged and transported from a distance.

• Microbiology and Biotechnology Letters
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• v.36 no.1
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• pp.55-60
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• 2008

Colored rices are a hulled grains having red or purple pigments in bran. Especially black rice (Heugjinjubyeo) is considered to be a healthy food in Asia. Black rice is of great interesting because of the possible biological activity with their anthocyanins. Anthocyanins are water-soluble plant pigments and representatives of flavonoids. The anthocyanins in black rice include cyanidin 3-O-glucoside, peonidin 3-O-glucoside, malvidin 3-O-glucoside, pelagonidin 3-O-glucoside and delphinidin 3-O-glucoside. In this study, anthocyanins in a black rice were analyzed quantitatively and qualitatively with HPLC and UV-Vis spectrophotometer. The anthocyanins contained approximately 95% of cyanidin-3-O-glucoside and 5% of peonidin-3-O-glucoside. Antioxidant activities of the anthocyanin extract were investigated by using various in vitro methods. The 100g/ml concentration of the anthocyanin extracted exhibited 88.83% inhibition on the peroxidation of linoleic acid, 55.20% DPPH free radical scavenging activity, 54.96% superoxide anion radical scavenging activity, and 72.67% hydrogen peroxide scavenging activity. And it also showed high ferrous ion reducing capability. These results suggest that the anthocyanin extracted from black rice may be utilized as a possible antioxdiant agent against ROS.

• The Korean Journal of Pharmacology
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• v.27 no.2
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• pp.145-153
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• 1991

Human neutrophil cathepsin-G, which has been known as one of the active enzymes causing inflammatory diseases, was purified by two steps procedure involving one size exclusion (Ultorogel AcA54) and one ion exchange (CM-Sephadex) chromatography. Purified HNCGs were cross-reacted with Anti-HNCathepsin-G antibodies which were radised in rabbits and purified by cathepsin-G labeled Sepharose 4B affinity chromatography. HNCGs were effectively inhibited by NSAIDs including phenylbutazone, sulindac, oxyphenbutazone, salicylic acid and salicyluric acid. $IC_{50}_s$ of these drugs for inhibition of Cathepsin G were 0.3-0.8 mM. Other NSAIDs including aspirin showed little or no inhibition effect on the activity of Cathepsin G. These results strongly indicated that NSAIDs which showed inhibition effect on the activity of HNCGs possibly be at least a part of mechanism of action which might be related to direct inhibition of cathepsin G at the tissue destruction sites beside of their known mechanism of action as an anticyclo-oxygenase in treatment of inflammatory diseases. Lipid soluble component of Korean Red Ginseng which was known as an anti-inflammatory agent inhibited HNCGs strongly, but no other fractions did inhibited HNCGs. Antibiotics including novobiosin and rifamycin showed some inhibition effect on HNCGs, i. e.., $IC_{50}$ of these drugs were 2.6 mM and 1.5 mM respectively, and other antibiotics including penicillin G showed no or negligible inhibition effect on the activity of HNCGs. However. tetracyclines inhibited HNCGs very effectively at the concentration of therapeutic range. The inhibition effect of the activity of HNCGs by tetracycline are not related to the N-dimethyl radical on the 4 position of the tetracycline molecule. Furthermore, N-dedimethylated tetracyclines may have beneficial effect for long term treatment of chronic inflammatory diseases without developing any drug resistance to microorganisms.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.490-497
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• 2002

Sintering property, mechanical property and bioactivity of $CaO-SiO_2-B_2O_3$ glass-ceramics were investigated. This glass-ceramics was sintered at 750-830${\circ}$ and showed nearly pore-free microstructure. The glass-ceramics consisted of three phases, i.e. monclinic-wollastonite, calcium borate and borosilicate glass matrix. The mechanical strength was higher than that of other bioactive ceramics, especially compressive strength(2813 MPa) and fracture toughness($3.12 MPa{\cdot}m^{1/2}$). Bioactivity of the glass-ceramics depends on amount of $CaB_2O_4$ and borosilicate glass matrix. It might be likely that more soluble $CaB_2O_4$ raises supersaturation of Ca ion in SBF solution and borosilicate glass forms Si-OH group that presents nucleation site of hydroxycarbonate apatite(HCA) layer. So, glassceramics of more $CaB_2O_4$ and borosilicate glass showed better bioactivity.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.411-418
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• 2005

Polymer-modified mortar and concrete are prepared by mixing either a polymer or monomer in a dispersed, or liquid form with fresh cement mortar and concrete mixtures, and subsequently curing, and if necessary, the monomer contained in the mortar or concrete is polymerized in situ. Although polymers and monomers in any form such as latexes, water-soluble polymers, liquid resins, and monomers are used in cement composites such as mortar and concrete, it is very important that both cement hydration and polymer phase formation proceed well the yield a monolithic matrix phase with a network structure in which the hydrated cement phase and polymer phase interpenetrate. In the polymer-modified mortar and concrete structures, aggregates are bound by such a co-matrix phase, resulting in the superior properties of polymer-modified mortar and concrete compared to conventional mortar and concrete. The purpose of this study is to obtain the necessary basic data to develope appropriate latexes as cement modifiers, and to clarify the effects of the monomer ratios and amount of emulsifier on the properties of the polymer-modified mortars using methyl methacrylate-butyl acrylate(MMA/BA) and methyl methacrylate-ethyl acrylate(MMA/EA) latexes. The results of this study are as follows, the water absorption, chloride ion penetration depth and carbonation depth of MMA/BA-modified mortar are lowest. However, they are greatly affected by the polymer-cement ratio rather than the bound MMA content and type of polymer.