• Journal of Korean Society of Environmental Engineers
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• v.31 no.3
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• pp.179-185
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• 2009

In this research, the removal capacity of Cr(VI) by the reused powdered wastes (RPW) containing aluminium oxides was studied. As a pre-treatment process for the preparation of calcined wastes, calcination was conducted at $550^{\circ}C$ to remove organic fraction in the raw wastes. In order to study the adsorption trend of Cr(VI) ions from aqueous solutions, the pH-edge adsorption, adsorption kinetic and adsorption isotherm were investigated using a batch reactor in the presence of four different background electrolytes($NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-},\;PO_4\;^{3-}$). Cr(VI) adsorption was greatly reduced in the presence of $SO_4\;^{2-}$ and $PO_4\;^{3-}$ over the entire pH range. Meanwhile the inhibition effect by $NO_3\;^-$ and $CO_3\;^{2-}$ was relatively lower than that by $SO_4\;^{2-}$ and $PO_4\;^{3-}$. Cr(VI) adsorption was maximum around pH 4.5 in the presence of $NO_3\;^-$ and $CO_3\;^{2-}$. As the concentration of background electrolytes increased, Cr(VI) adsorption decreased. This result mightly suggests that adsorption between the surface of RPW and Cr(VI) occurs through outer-sphere complex. Cr(VI) adsorption onto the RPW was well described by second-order kinetics. From the Langmuir isotherm at initial pH 3, the maximum adsorbed amount of Cr(VI) onto the RPW was 11.1, 10, 3.3, 5 mg/g in the presence of $NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-}$, and $PO_4\;^{3-}$, respectively.

• Journal of the Korean Society of Costume
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• v.51 no.4
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• pp.5-14
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• 2001

Excavated costumes at the women's tomb in 17C have been sustained good condition. These materials give us that Jang ui(長衣) and so chang ui(소창의) with chechori(유), skirt, trousers(袴) reflects on women's fashion style at that time. By seeing these costumes, we can get the characteristics of costumes in mid-chosun era with chechori, skirt, jang ui, so chang ui etc. The features of chechori in this area are follows : form - diagonal gil, collar - kalkit and tangkokit, length - about 50cm, materials - silk, cotton, grass-cloth, kind - single, double. clothing padded with cotton wool etc. It is the first time that chang ui, one of Po, is excavated in this area. There are three pieces of jang ui which is significant data to study deeply on the costume in 1700's. Jang ui mainly made of silk in pattern, silk, cotton and decorated stylish printing on the robes. With these material and style, we can induce the mode of mid-chosun period. Through comparative studying we have many chances to understand women's the garment for the dead(염습의) in mid-chosun period.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1094-1097
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• 2001

The control method of Thyristor-controlled Reactor(TCR) is described in this paper for compensating the poor power factor, unbalanced and/or nonlinear load. Also, auxiliary controller such as DC current and power-factor controller is described. The reference current of TCR is calculated from the active and reactive current components for each of the positive and negative sequence components in the load currents. This reactive power control technique was verified by Matlab Simulink and 33Kvar TCR simulator, and will be used in 4.3Mvar TCR system, which will be installed next year at R-Tech Co., located in Po-Hang.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.627-628
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• 2008

We have studied the optical performance of flexible polymer network liquid crystal (PNLC) films at various bending states. Different measurement setups, wide and narrow opening angles of detector, were used to collect scatting light of PNLC films. The optical and dynamic properties of bent PNLC implied the change of LC domains.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1295-1298
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• 2006

Influences of anti-reflection surface treatment, radius of curvature and ambient illuminance on legibility of reflective-type displays were studied. The results showed that legibility mainly depended on the surface treatment. Better surface treatment also produced less visual fatigue after the letter-search task

• Advances in aircraft and spacecraft science
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• v.1 no.4
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• pp.443-454
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• 2014

An experimental study was conducted to investigate the effect of Reynolds number on compressible convex-corner flows, which correspond to an upper surface of a deflected flap of an aircraft wing. The flow is naturally developed along a flat plate with two different lengths, resulting in different incoming boundary layer thicknesses or Reynolds numbers. It is found that boundary layer Reynolds number, ranging from $8.04{\times}10^4$ to $1.63{\times}10^5$, has a minor influence on flow expansion and compression near the corner apex in the transonic flow regime, but not for the subsonic expansion flow. For shock-induced separated flow, higher peak pressure fluctuations are observed at smaller Reynolds number, corresponding to the excursion phenomena and the shorter region of shock-induced boundary layer separation. An explicit correlation of separation length with deflection angle is also presented.

• Journal of Animal Science and Technology
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• v.51 no.3
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• pp.249-254
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• 2009

The effect of Mg supplement on the composting of swine manure and the formation of $MgNH_4PO_46H_2O$ (MAP) crystal during composting were examined. Mg source was added at a rate of 1.2 molar ratios to soluble phosphate ($PO_4$) level in swine manure. The temperature profiles and final compost qualities revealed that the Mg source addition didn't retard the decomposition of organic matters. As the added Mg reacted with $NH_4$ and $PO_4$ in manure, creating MAP crystal, the $NH_4$ level was reduced, and this was resulted in low nitrogen lose during the composting. The phosphate level was also decreased with the addition of Mg source, and hence the ratio of orthophosphate to total phosphate (OP/TP) in the final compost was lowered. Therefore, it was assured that supplement of Mg source into the composting materials could enhance the quality of compost by preserving nourishment and converting it into a slowly releasing fertilizer. X-Ray diffraction examination of the final compost showed that a distinct MAP crystal was formed during the composting, and the crystal mainly existed with the compost particle size less than 2.8 mm and over 2/3 of nourishment of the final compost was found in those particles.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.1
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• pp.1-8
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• 2007

Environment factors related to the distribution of organic matter in surface seawater and sediments were investigated to estimate main pollution sources and range of their influence in Gwangyang Bay. The main pollution sources for the factors that affect organic matter distribution could be divided into three main sources: fresh water runoffs from Seomjin and Dong River, Gwangyang-si domestic sewage, and Yosu Industrial Complex. Considering the characteristics in horizontal distributions of the environmental factors in water column, sediment, and water current regime, the influencing range of these main sources was likely to be divided into three areas within the bay as follows: Area I receiving lots of fresh water from Seomjin River, Area II receiving lots of domestic sewage from Gwangyang-si and fresh water of Dong River, Area III receiving lots of materials from Yosu Industrial Complex. Area I seems to be characterized as low salinity, high concentration of $NO_3-N,\;and\;SiO_2-Si$, Area II as low salinity, high concentration of $NO_3-N,\;NH_4-N,\;and\;SiO_2-Si$, and Area III as high water temperature, high concentration of $NH_4-N,\;and\;PO_4-P$ in water column, high concentration of $NH_4-N,\;PO_4-P,\;and\;SiO_2-Si$ in surface sediments.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.329-334
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• 1998

This study was conducted in order to investigate removal rate of organic matter, nitrogen and phosphorus to reduce environmental polluation with treatment to attach combined septic tank to 3 stage soil filter after mixing anaerobic treated water of livestock wastewater and low concentrated wastewater generated in farm house. Because anaerobic filter bed was packed in combined septic tank and a microorganism was accumulated in combined septic tank with increasing hydraulic retention time(HRT), if HRT $4{\sim}12day$, CODcr was removed $63.4{\sim}84.0%$. Also, $NH_4\;^+-N$ and $PO_4\;^{3-}-P$ were removed $3.9{\sim}5.4%$ and $18.3{\sim}29.0%$, respectively. In being re-treated by 3 stage soil filter, although hydraulic loading rate was gradually increased, CODcr, $NH_4\;^+-N$ and $PO_4\;^{3-}-P$ were removed above 90% due to filtration, adsorption, ion exchange, and action of soil microorganism. Generally, the attached treatment of combined septic tank and 3 stage soil filter did suitably treat livestock wastewater to water standard of discharge applied from '96 year, in view of decreasing pollution loading amount and recycling of agricultural water.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.683-688
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• 1993

The antioxidative effect of the 75% ethanol extracts of preliminary selected Fritillaria ussuriensis Max(Fs), Houttuynia cordata Thunb(Hc), Portulaca oleracea L.(Po) and Perilla frutescene Var javanica Hara cake(Pf) were tested on palm oil and lard by rancimat test. Each solvent fraction of chloroform, ethyl acetate(EtOAc), butanol and water, was also evaluated its antioxidative effect with some synergists, like as ascorbic acid, citric acid and ${\delta}-tocopherol$. Po extract showed higher antioxidative effect on lard and the fraction of all test plants were the most effective on palm oil and lard with ascorbic acid and ${\delta}-tocopherol$. When 200 ppm of EtOAc fraction of Fs, He and Po extract each with 200 ppm of ascorbic acid were added to palm oil, the antioxidative index(AI, induction time of oil containing each extract/induction time of test oil) were 1.60, 1.53 and 1.47 respectively and 200 ppm of EtOAc fraction of Po and Pf extract each with 200 ppm of tocopherol to lard, the AI were 3.19 and 3.63 respectively.