• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.5
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• pp.905-914
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• 1996

To study the effect of the bleaching agents in detergents on the degradation of cotton fabrics, the carboxyl contents, copper numbers, degree of polymerization, the change of tensile strengths and fiber surfaces of cotton fabric before and after washing were examined. The results obtained were as follows: As the cycles and temperature of washing increased, the carboxyl content of washed cotton fabric changed little but the copper unmber of cotton fabric was increased. At 6$0^{\circ}C$ , 8$0^{\circ}C$ the copper number of cotton fabric washed with soidum perborate (PB) was higher than that of with sodium percarbonate (PC). The degree of polymeriazation and tensile strength of cotton fabric were decreased and at higher temperature those were more decreased but were less decreased when tetraacetyehylenediamine (TAED) was added. The degree of polymerization had negative relation with copper unmber but with tensile strength of cotton fabric had positive relation. Cotton fiber surface was more degraded by bleaching agents and hydrogen peroxide exhaustion was increased as the temperature of washing increased. And hydrogen peroxide exhaustion had negative relation with the degree of polymerization.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.156-159
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• 2010

Peroxide is used frequently to provide electron acceptors to aerobes for the purpose of in situ bioremediation of contaminated soil/sediment. In this study, oxygen release rate of peroxides and factors affecting on dissolution and diffusion of oxygen into pore water were evaluated. Peroxides studied in this study were magnesium peroxide ($MgO_2$), calcium peroxide ($CaO_2$), and sodium percarbonate ($Na_2CO_3{\cdot}1.5H_2O_2$). $Na_2CO_3{\cdot}1.5H_2O_2$ showed the highest oxygen release rate per unit mass and the shortest release duration time among three peroxides. A simple first-order decay model for predicting the release rate of oxygen from peroxide into pore water was presented and used to fit the experimental data. The first order oxygen release rate constants k for $MgO_2$, $CaO_2$ and $Na_2CO_3{\cdot}1.5H_2O_2$ were 0.45 /hr, 3.22 /hr and 134 /hr, respectively. If $MgO_2$ was mixed with clay, oxygen release rate was lowered significantly mainly due to limitation of contact area and diffusion, implying that oxygen can be provided to the indigenous aerobes for the extended period of time.

• Applied Chemistry for Engineering
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• v.1 no.1
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• pp.91-99
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• 1990

For-${\alpha}$-APM was efficiently prepared by the reaction of For-Asp anhydride and Phe-OMe in methylethylketone, $CH_3CN$, and in water. The selective recovery of For-${\alpha}$-APM from the resulting For-${\alpha}$-APM and For-${\beta}$-APM mixture was possible via repetitive extraction at constant pH of 4.00. The oxidative deformylation was successfully performed by using several oxidants including $H_2_O2$/THF, sodium percarbonate, and $H_2_O2$/HCl/MeOH giving APM in high yields. The efficiency of the oxidative deformylation was raised in acidic condition for all the deformylation reactions.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.222-234
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• 2017

Green tides, which was mainly caused by Ulva spp., have been increasing in severity and frequency globally, and have negatively affected on marine ecosystems. This study was conducted to investigate effects of various physical and chemical factors on the death of Ulva australis (ULAUS) and to consider a practical measures useful for alleviating Ulva bloom. Soaking of ULAUS thalli in pure water for 8 hr didn't induce a death, but incubation in 1.0-1.5% salinity for 7 d inhibited sporulation by about 70%. Desiccation gave rise to a serious damage when more than 40-50% of initial fresh weight was lost. ULAUS growth was sensitive to temperature and seriously inhibited from more than $30^{\circ}C$. At $35^{\circ}C$, $40^{\circ}C$, $45^{\circ}C$ and $50^{\circ}C$, treatment time required for 90-95% death of ULAUS thalli was 1 d, 10 min, 30 sec, and 1 sec, repectively. ULAUS growth was seriously inhibited at lower than pH 6.0 and completely dead at pH 4.0. Several compounds for ULAUS control was selected and the chemcals causing a rapid death were oxidants such as hydrogen peroxide and sodium percarbonate. Taken together, our results suggest that low salinities, dryness, pH, high temp. and compounds could be selected for Ulva bloom control, and high temperature and compounds seems to be useful for a development of practical control methods.