• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.75-78
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• 2003

This study is to investigate the probability to develop the AE Water-reducing agent which can decrease the bleeding by mixing melamine type super-plasticizer(SP) and methyl cellulose(MC) viscosity agent. According to the result, as the mixing ratio of melamine type SP and MC viscosity agent increases, the bleeding is reduced due to a increase of the air content. When the mixing ratio of melamine type SP and MC viscosity agent is 1:2 and 1;3 at the water content of 165kg/$m^3$ and 175kg/$m^3$ respectively, slump and air content are satisfied and bleeding is reduced to some extent, so this is determined as the mixing ratio of AE water reducing agent for reduction of bleeding. It is prove that the developed AE water reducing agent for reduction of bleeding can reduce the amount of bleeding and prohibit the plastic shrinkage crack by slowing down the bleeding speed. Compressive strength of hardened concrete does not make any difference in comparison with plain concrete.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.356-363
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• 1997

Many research works have been carried out to investigate the factors governing the performance of diesel engine. The area of the study has been focused on reducing both of NOx and smoke because of many difficulties to reduce them simultaneously in diesel engines. One of the efforts is an application of EGR technology to reduce NOx emission, which is very effective, but increases other emissions and makes fuel economy worse. In order to solve the problem, EGR is employed with water emulsified fuel and tested in this paper. Emulsified fuel is produced by centrifugal mixer and the amount of water is controlled by water injector and pulse generator, and EGR rate is controlled with 6-step control valve. The chamber pressure, fuel consumption and emissions are measured with various values of both EGR and water mixing rate, The results show that NOx emission is reduced much rather and smoke is also reduced simultaneously.

• Korean journal of food and cookery science
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• v.11 no.4
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• pp.337-341
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• 1995

The effect of time and amount of water by conventional blanching method on the retention minerals in spinach and broccoli was investigated. The vegetables were blanched for 1, 2, 3 and 4 minutes, with 150 $m\ell$, 300 $m\ell$, 450 $m\ell$ of water for every 100 g of raw material. Blanching of spinach showed that Na was reduced remarkably after 2 minute of blanching, the others (K, Fe, Ca, Mg, P, Cu) were gradually decreased as the blanching time increased. Blanching of broccoli showed that the content of minerals were reduced remarkably after 1 minute of blanching. The longer blanching time further reduced the content of minerals. The retention of minerals (Na, K, Fe, Ca, Mg, P, Cu) in spinach and broccoli was reduced gradually as the blanching water increased. The retention rate of minerals were 12.7％ of Na, 37.4％ of K, 37.1％ of Fe, 43.9％ of Ca, 39.0％ of Mg, 53.5％ of P, 56.2％ of Cu in spinach and 21.0％ of Na, 41.3％ of K, 57.8％ of Fe, 38.8％ of Ca, 51.5％ of Mg, 57.7％ of P, 44.4％ of Cu in broccoli for 4 min, with water 450$m\ell$ every 100g of raw material.

• Membrane Journal
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• v.23 no.3
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• pp.220-225
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• 2013

Hydrophilic monomers were polymerized for lamination on polyvinylidene fluoride (PVDF) membrane surface for hydrophilization of the membranes. Hydrophilization reduced the contact angle from $95^{\circ}$ to $55^{\circ}$ and enhanced the water flux by 10 times while it reduced the bovine serum albumin (BSA) adsorption amount to 1/4 level. Thermal polymerization process was optimized by examining several operation parameters. Dimethyl oxobuthyl acrylamide (DOAA) showed the best effect due to its better hydrophilicity than others. Increase of amount of monomer enhanced the performance until the optimum concentration of 30 wt%, beyond which excess amount of monomer resulted in homopolymerization to deteriorate the performance. Azobis (isobutyronitrile)(AIBN) initiator has greater activation temperature range than benzoyl peroxide (BPO) and it showed better hydrophilation performance. Two stage lamination process, application of initiator followed by monomer addition, was more effective than one stage process, addition of initiator and monomer at once, which still reduced the contact angle but also reduced the water flux by pore blocking phenomena.

• Water for future
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• v.35 no.5
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• pp.21-30
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• 2002

The inflow into a multi-purpose dam reservoir contains many suspended solids from the upper stream during the rainy season. Concentrations of SS increased to 73.3 mg/l and the TP measurement increased to 0.09 mg/l during the rainy season in 1999. It was discovered that particles less than $10\;\mu\textrm{m}$ in size composed about 50% of the total amount. Some of these particles reduce the reservoir capacity and have an impact on water. In this study, the sediment depth at Daecheong multi-purpose dam was examined. Piston coring was performed at 9 locations At Hoenam 1 out of 9 locations examined showed maximum depth, which was 90 cm and at Muneui 3 showed the minimum depth, which was 35 cm. At Hoenam, the release rate of TN was found to be $62.14~84.72\;mg/\textrm{m}^2{\cdot}day$ in 1998. However, it was found to considerably reduced to $23.20\;mg/\textrm{m}^2{\cdot}day$ in 2001. The release rate of TP was measured at $13.02~14.38\;mg/\textrm{m}^2$.day at 1998, and it was reduced to $6.93mg/\;mg/\textrm{m}^2{\cdot}day$ in 2001.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.465-470
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• 2012

Objectives : In general, the active of volatile compounds which become usually known as the principal ingredient of bad breath is closely connected with temperature. In this study, an investigation was made into the correlation between oral malodor and the temperature of rinsing water. Specifically, an analysis was made of saliva in rinsing water with relation to amount, flow and pH. In addition, a calculation was made of O'Leary index. The results are expected to be basic data for oral malodor reduction plans. Methods : A total of 30 women who are in their 20s without any systemic disease and teeth braces and non-pregnant were chosen for the study. The research was carried during 3 weeks from 28 Mar to 11 Apr in 2011. Results : Saliva was not significantly affected by the temperature of rinsing water, in connection with saliva amount, saliva flow and saliva pH. The O'Leary index and oral malodor was the highest in warm water, but the subjects preferred rinsing with cold water. Conclusions : In conclusion, oral malodor was found to be reduced in inverse proportion to the temperature of rinsing water. Thus, it is recommended to rinsing water with warm water after tooth brushing.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E4
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• pp.169-175
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• 2003

The effect of gas composition on the discharge characteristics and the ozone production in silent discharge (SD) process was investigated. The major gas components, $N_2$, $O_2$, and $H_2O$ influence the discharge properties according to their relative magnitude of ionization thresholds and electron affinities. The generated amount of ozone increased with the discharge energy by increasing the electron mean energy. The higher oxygen content injected, the higher ozone produced. A small amount of water vapor significantly lowered the discharge onset voltage by the ionization threshold decreasing effect and high electrical conductivity. However, the further increase of water vapor contributes to decrease the electron density by the electron affinity The addition of water greatly reduced the ozone generation through the formation of OH radical and the catalytic ozone destruction process.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.164-171
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• 1999

A new technique for recycling process water was developed in order to reduce the calcium hardness of the closed OCC recycling system. Calcium ions present in the white water were precipitated as calcium carbonate by a reaction with sodium carbonate and the CaCO$_3$precipitates were easily removed from the system by a dissolved air flotation(DAF) method. After the DAF stage, CO$_2$-gas was purged into the water because the pH of Na$_2$CO$_3$-treated white water was reduced to neutral by CO$_2$gas. Since CaCO$_3$precipitate tends to stick onto the fine fiber surface and then is selectively removed from the water, a proper amount of suspended solid in the process water acts as an important factor in deciding the removal efficiency. By the application of Na$_2$CO$_3$addition - DAF - CO$_2$purging to the short circulated white water the calcium hardness was significantly reduced by 92% and more. The removal of calcium ions with fine fibers led to drainage improvement, reduction of fresh water consumption, and enhanced efficiency of wet-end chemicals.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.2
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• pp.15-24
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• 1999

A new technique for recycling of white water was developed in order to reduce the calcium hardness in a closed OCC recycling system. Calcium ions present in the white water were precipitated as calcium carbonate by reacting with sodium carbonate, and the precipitated $CaCO_3$ was removed from the system using a flotation fractionation method, which has been commonly used in deinking process. In the flotation stage, a mixed gas of $CO_2$-air was purged into the flotation cell because the pH of $Na_2CO_3$-treated white water was reduced to neutral by $CO_2$ gas. Since $CaCO_3$ precipitate tends to stick onto fine fiber surface and then selectively removed from the white water, a proper amount of suspended solid in white water acts as an important factor for deciding the removal efficiency. By the application of $Na_2CO_3$ addition-$CO_2$ flotation to the short circulated white water, the calcium hardness was significantly reduced by 87% and more. Removal of calcium ions with fine fibers led to a drainage improvement, reduction of fresh water consumption, and enhanced efficiency of wet-end chemicals.

• Plant Resources
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• v.8 no.2
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• pp.103-109
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• 2005

Lettuce (Lactuca sativa L.) is known to contain water-soluble substances that improve antioxidant status due to the richness in antioxidants. Greenhouse experiment was carried out under different shading conditions during spring lettuce growing season. Shade significantly reduced shoot weight, number of leaves and chlorophyll content, while it increased shoot length of lettuce plants. The antioxidant potential of the individual fraction was in order of n-butanol > ethyl acetate > water > n-hexane fraction, although was less than that of commonly used antioxidants, BHT and ascorbic acid. Fractions from lettuce plants dose-dependently increased DPPH free radical scavenging activity, in vitro test. By means of HPLC analysis, BuOH fraction of cultivar 'Hwahyang' (57.93 mg $100g^{-1}$) had the highest amount of antioxidant chi orogenic acid. Shading treatment increased average amount of chlorogenic acid of all cultivars in BuoH, EtOAc, hexane and water fractions by 33, 120, 144, and $58\%$, respectively. These results suggest that lettuce plants had potent antioxidant activity, and their activities were differently exhibited depending on cultivar and fraction.