• Journal of the Korean Wood Science and Technology
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• v.46 no.2
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• pp.178-188
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• 2018

The aim of this study was to assess the in vitro potential of water extract from torrefied oak wood as a natural antioxidant. The antioxidant potential of the extracts was assessed by employing different in vitro assays, including reducing power, DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)], and FRAP (ferric reducing antioxidant potential) assays. The DPPH activity of the extract was increased in a dose-dependent manner. Measurement of total flavonoid content of water extract from torrefied oak wood was achieved using an aluminum chloride colorimetric assay; the extract contained 192.12 mg/g flavonoid, which was significantly high when compared with standard quercetin. The results obtained in this study indicate that water extract from torrefied oak wood has significant potential for use as a natural antioxidant agent.

• Korean Journal of Microbiology
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• v.20 no.3
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• pp.119-124
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• 1982

As a basic study to elucidate nutritional physiology and composition of synthetic medium of red rotting bacteria, Erwinia carotovora, of ginseng, the effects of hydrogen ion concentration, various kinds of carbon sources, nitrogen source, micrometallic salts and it's concentration on the gorwth of the bacteria were investigated and the results were as follows. Optimal pH in the basal medium for the growth of the bacteria was 6.5. After incubation the pH in culture media was neutralized. Among the various kinds of carbon sources, sucrose, glucose mannitol, but organic acids were not utilized effectively as nutrients. After incubation the pH turned acidic. Alanine as organic nitrogen sources nad ammonium sulfate as inorganic nitrogen promoted the growth, but L-valine and sodium nitrite were the least effective. Ferric chloride 1.0mg/dl and ferrous sulfate 100mg/dl were the most effective as micrometallic sources. Control and boric acid were the least effective. New synthetic medium based on the above results was follows ; Alanine 1.0g, $KH_2PO_4\;1.0g, \;sucrose\;30.0g, \;MgSo_4{\cdot}7H_2O\;0.5g, \;FeCl_3{\cdot}6H_2O\;1.0mg\;thiamine\;200{\gamma}g$, and distilled water 1000ml, pH6.5.

• Textile Coloration and Finishing
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• v.16 no.6
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• pp.16-22
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• 2004

This study was carried out to investigate K/S values, surface color, the fastness to washing, bacteria reduction rate of the silk and cotton fabrics dyed with Rhus verniciflua extract under the various dyeing conditions. The optimum dyeing temperature, dyeing time, dyeing pH and repetition of the silk fabrics dyed with Rhus verniciflua extract were $l00^{\circ}C, 30min., pH 5, five times repetition respectively, but in the cotton fabrics, it were $60^{\circ}C . 30min., pH 7, one times repetition. It were colored orangish Yellow in the silk fabrics and colored bright yellow in the cotton fabrics dyed with Rhus verniciflua extract. Surface color(munsell value) was not changed by the mordanting agents but those of the silk showed high tone when mordanting with stannous chloride, and it was decolored and darked when mordanting with ferric sulfate. The fastness to washing in the silk fabrics dyed with mordanting agents improved in 4～5 grade, but the cotton fabrics were 3～4 grade, so washing fastness of the silk and cotton fabrics were significantly improved when washing with the neutral detergent. The bacteria reduction rate of the silk fabrics increased drastically by dyeing of Rhus verniciflua extract.

• Advances in nano research
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• v.2 no.4
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• pp.187-198
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• 2014

Magnetite nanoparticles (MNPs) of different sizes were synthesized by solvothermal process maintaining their stoichiometric composition and unique structural phase. Utilizing hydrated ferric (III) chloride as unique iron precursor, it was possible to synthesize sub-micrometric magnetite clusters of sizes in between 208 and 381 nm in controlled manner by controlling the concentration of sodium acetate in the reaction mixture. The sub-micrometer size nanoclusters consist of nanometric primary particles of 19 - 26.3 nm average size. The concentration of sodium acetate in reaction solution seen to control the final size of primary MNPs, and hence the size of sub-micrometric magnetite nanoclusters. All the samples revealed their superparamagnetic behavior with saturation magnetization ($M_s$) values in between 74.3 and 77.4 emu/g. $M_s$. The coercivity of the nanoclusters depends both on the size of the primary particles and impurity present in them. The mechanisms of formation and size control of the MNPs have been discussed.

• Journal of Applied Biological Chemistry
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• v.44 no.1
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• pp.12-15
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• 2001

The antioxidative compounds and antioxidant contents of ginger (Zingiber officinale) rhizomes were determined. Substances reextracted using ethyl acetate from crude methanol extract of fresh ginger rhizome were separated through thin layer chromatography. Ten phenolic antioxidative bands were visualized through color reactions using ferric chloride-potassium ferricyanide and 1,1-diphenyl-2-picrylbydrazyl (DPPH). The antioxidative compounds were purified through preparative TLC and high performance liquid chromatography (HPLC), among which, five antioxidants were identified as 4-, 6-, 8-. and 10-gingerols and 6-shogaol on the basis of their molecular weights determined through LC-MS. As shown in experiments using DPPH free radicals, 6-Gingerol and PT4-HP8 (unknown) were revealed to be more efficient than BHT (butylated hydroxy toluene). Contents of gingerols were determined through reverse phase HPLC. Total gingerol contents (sum of 6-,8-, and 10-gingerols) in rhizomes of different ginger varieties varied significantly. The HG55 (collected at Wanju district in Korea) and the HG52 (imported from Brazil) showed the highest gingerol contents.

• Resources Recycling
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• v.2 no.4
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• pp.27-32
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• 1993

A process has been studied to recover gallium from steelmaking dust which had several hundreds ppm of gallium. Aqueous solution containing 38 mg/l gallium was obtained by leaching of dust with 2.25 mol/l sulfuric acid. The leach liquor contained iron and zinc about 1,000 times greater than gallium. Gallium was then concentrated by ion exchanger of chelating resin with functional group of amino carboxylic acid after reduction of ferric ion to ferrous ion and pH adjustment. Gallium was concentrated to be 13 g/l in the resulting eluate by double ion exchanges. The liquor was further treated to remove impurities by solvent extraction technique empolying TOMAC as extractant. The galluim with 99% purity was finally obtainable.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.1
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• pp.1-8
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• 1994

Laboratory experiments were conducted to investigate the effect of digestion temperature on the settleability and dewaterability of anaerobically digested sludge. The digesters were operated at a hydraulic retention time of 20 days with a loading rate of 0.63~0.66kg volatile solids per cubic meter per day at the temperature of $35^{\circ}C$ and $55^{\circ}C$. A mixed primary and secondary municipal sludge was used as a feed. The interface height of the sludge during settling test was recorded to identify settleability. As a measure of dewaterability of the sludge, specific resistance and capillary suction time were also measured with and without chemical conditioning. Higher digestion efficiency was obtained at $55^{\circ}C$ than $35^{\circ}C$. However, the settleability and dewaterability of the sludge at $35^{\circ}C$ were quite higher than those of the sludge digested at $55^{\circ}C$. The optimum dosages of ferric chloride for sludge conditioning were 0.4% and 0.6% at $35^{\circ}C$ and $55^{\circ}C$, respectively. The filtrate COD of the sludge digested at $55^{\circ}C$ was higher than at $35^{\circ}C$, which means that poor dewaterability of the sludge result in high filtrate COD.

• Korean Journal of Microbiology
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• v.15 no.3
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• pp.123-130
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• 1977

In previous paper, it was reported that antibiotic substance such as tetracycline and streptomycin were produced by S'. albus subsp. and S'. globosus. And increase of mycelial growth of two strains, antibiotic production, and changes of pH range are extended to approximately 110-130 hrs in fermenting medium, there-after they decreased with culture period exception of pH range. Two Streptomyces spp. required commonly 4-5% starch as carbon sources and 1.5-2.0% soybean meal as nitrogen sources. However, 0.005-0.01M potassium phosphate dibasic, calcium carbonate (6mg/ml in S.albus subsp. and 2mg/ml in S. globosus), 0.01-0.03M, magnesium sulgate and 0.01M ferric chloride showed as optimal concentration for the growth of 2 strains. Mineral compoments such as zinc, manganese, cobalt, sodium and copper at the level of 10/sup -4/ -10/sup -6/M were observed. Especially, zinc ion showed toxicity to the growth of 2 strains at 0.005M. In relation with pH, there is a little difference in mycelial growth with cultural initial pH.

• Journal of Distribution Science
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• v.17 no.4
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• pp.51-57
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• 2019

Purpose - This study aims to improve the distribution structure of the OLED market and develop cost-effective optimization techniques. Specifically, it is a study on the optimization of ferric chloride to improve the etch of SUS MASK for OLED. Research design, data, and methodology - Applying the optimal conditions of the experiment, the final confirmation was evaluated for improvement by the Process Capability Index (Cpk). It is possible to derive social performance such as improvement of precision of SUS MASK manufacturing, economic performance such as defect rate, reduction of waste generation and treatment cost, technological achievement such as SUS MASK production technology, improvement of profit structure of technology development and process improvement do. Results - The improvement of the Cpk before the improvement was made was confirmed to be 0.57% with a defect estimate of 25.07% with a failure estimate of 0.57% after the improvement, and 8.84% with a failure estimate of 0.57% level after the improvement. Conclusions - If the conclusions obtained from the specimen experiment are applied to the manufacturing process of SUS MASK, it will be possible to expect excellent cost-effective competitiveness due to the improvement of precision and reduction of defect rate to enhance the OLED market penetration.

• Korean Membrane Journal
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• v.7 no.1
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• pp.58-66
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• 2005

Nanofiltration (NF) of a dyeing wastewater was carried out using polyamide NF-membranes. Before applying the wastewater to the membrane process, it was pretreated with various chemical coagulants such as alum, ferric chloride and HOC-100A. In order to see the effect of the pretreatment of the wastewater using chemical coagulants on the membrane separation process, the optimum conditions for the coagulation and sedimentation process using the chemical coagulants were sought. By the pretreatment, despite the different coagulants used, the chemical oxygen demand (COD) and UV-absorbance of the wastewater were lowered by more than $70\%$. The pretreated wastewater was then applied to the membrane process. The effect of the coagulants used for the pretreatment on the membrane fouling was studied. From this study, it was found that the HOC-100A was the best out of the coagulants used far the removal of the materials that could cause membrane fouling.