• Journal of Environmental Science International
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• v.22 no.7
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• pp.905-913
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• 2013

We compared the applicability and economical efficiency of peroxone process with those of ozone process in the existing water treatment plant on downstream of Nakdong River. After comparing the peroxone process for removing geosmin with the ozone process in lab scale test, peroxone process showed much higher removal efficiency than the ozone process at the same ozone dosage. Proper range of $H_2O_2/O_3$ ratio were 0.5~1.0 and the half-life of geosmin was about 5.5~6.8 min when the $H_2O_2/O_3$ ratio was set to 0.5 during 1~2 mg/L of ozone dosage. Peroxone process could reduce the ozone dosage about 50 to maximum 30% for the same geosmin removal efficiency compared to the ozone process in the pilot scale test. In case of 1,4-dioxane treatment, peroxone process could have 3~4 times higher efficiency than ozone process at the same ozone dosage. The results of estimating the economical efficiency of ozone and peroxone process for treating geosmin and 1,4-dioxane by using pilot scale test, in case of the removal target was set to 85% for these two materials, the cost of peroxane process could be reduced about 1.5 times compared to ozone process, and in the same production cost peroxone process could have 2~3 times higher removal efficiency than ozone process. The removal efficiency by peroxone process showed a large difference depending on the physicochemical characteristics of target materials and raw water, therefore detailed examination should be carried out before appling peroxone process.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.1
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• pp.100-107
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• 1998

Polyester filaments were dyed with disperse dye in dyebath containing water and water miscible organic solvents . acetone, 1,4-dioxane, DMF. In case of Acetone and 1,4-dioxane, the equilibrium dyeuptake was maximun at the volume fraction 0.05. The equilibrium dye uptakes were decreased as volun~e fraction of organic solvents were increased. When the volume fractions of water miscible organic solvents were varied, dye uptake was increased constantly with dyeing time. In dyebath containing water and water miscible organicsolvent, the dyeuptake was increased quickly during initial 40∼ 60 min. and slowly increased there after. The slope of Ct/Coo to t was greater in dyebath containing water and water miscible organic solvents than dyebath containing water. The differences of the slope with volulne fractions of water miscible organic solvent were not shown big.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.503-508
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• 1987

The protonation constants of 3,4 : 9,10-dibenzo-1,12-diaza-5,8-dioxacyclotetradecane $(NenOenH_4)$ and stability constants of its transition metal complexes have been determined by the potentiometric titration in 1 : 1 dioxane-water mixture with 0.1 ionic strength at $25^{\circ}C.$ For a given anion system, the stabilitv constants of the complexes are in the order of $Mn^{2+}<\;Co^{2+}\;< Ni^{2+}\;<\;Cu^{2+}\;>\;Zn^{2+}$, which accords with the Williams-Irving series.

• Membrane Journal
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• v.20 no.4
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• pp.304-311
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• 2010

In this study, loose RO hollow fiber membranes using CTA polymer were prepared by phase inversion method and their water purification properties were tested. 1,4-dioxane and LiCl was used as a skin layer formation agent and pore formation agent, respectively. Water flux, salt rejection, chlorine resistance, MWCO and membrane morphology were evaluated as a function of the dope composition. When the membrane prepared using the dope solution of CTA/NMP/1,4-dioxane = 18/72/10 (wt%) with air gap of 30 cm, it shows improved RO performance such as $20.5L/m^2hr$ of water flux, 60% of NaCl rejection, 10,000 ppm/hr of chlorine-resistance and around 5,000 Da of MWCO.

• Analytical Science and Technology
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• v.18 no.3
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• pp.173-187
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• 2005

• Analytical Science and Technology
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• v.8 no.4
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• pp.793-798
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• 1995

A new chromoionophore sym-(decyl)(2-hydroxy-5-nitrobenzyloxy)-dibenzo-16-crown-5 (1) has been synthesized for $Na^+$ photometry in aqueous media. Apparent $pK_a$ values of 1 in the presence of 0.10 M LiCl, NaCl, and KCl were measured by spectrophotometry in 50% 1,4-dioxane-50% water (v/v) and compared with the $pK_a$ of 8.68 in the presence of 0.10 M TMACl. A significant $pK_a$ shift to a lower pH was only observed for $Na^+$ (${\Delta}pH=1.31$) due to selective binding of 1 with $Na^+$. Based upon this $pK_a$ shift, chromoionophore 1 was found to selectively respond to $Na^+$ with a detection limit of $10^{-3}M$ and no interference from $K^+$ up to 0.05 M for detection of 10.0 mM $Na^+$ in 50% 1,4-dioxane-50% water (v/v).

• Analytical Science and Technology
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• v.8 no.1
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• pp.47-53
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• 1995

The aggregation of Pyronin G($PG^+$) with tetraphenylborate($TPB^-$) anion has been investigated in aqueous solution by absorption and fluorescence spectrophotometries. The addition of 1,4-dioxane in aqueous solution of $PG^+$ and $TPB^-$ dissociates the aggregates of PG-TPB due to the increased hydrophobicity of the mixed solvent as compared to pure water, and yields higher $PG^+$ momomer concentration than aqueous $PG^+$ solution. The aggregation is not observed in any organic solvents except in water. The absorption maxima of $PG^+$ are correlated relatively well with ${\pi}^*$ scale and $(n^2-1)/(2n^2+1)$ funtion. But better linear relationship was obtained with ${\pi}^*$ scale for alcohols.

• Polymer(Korea)
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• v.34 no.4
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• pp.381-385
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• 2010

Aiphatic diester monomer, 3-[(benzyloxycarbonylamino)butyl]-1,4-dioxane-2,5-dione (BABD), was synthesized with the N-$\varepsilon$-benzyloxy-carbonyl-L-lysine as starting material. This monomer was synthesized to add the functionality to poly(lactic acid)s. BABD unit was successfully incorporated into the PLLA chain which was confirmed by $^1H$ NMR. The copolymer composition could be controlled by the feed ratios of monomer. The $M_n$ of this resultant polymer is expected to reach high molecular weight after the purification of monomer and optimization of polymerization time, though the polymer showed relatively low degree of polymerization ($M_n$＝3300). The copolymer is expected to possess the enhanced hydrophilicity and the possibility of chemical modification on amino group.

• Journal of Photoscience
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• v.12 no.1
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• pp.51-54
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• 2005

The electronic excitationenergy quenching of 2, 5-diphenyl-1, 3, 4-oxadiazole (PPD) by Carbon tetrachloride ($CCl_4$) in different solvents viz, n-hexane, n-heptane, toluene, benzene, cyclohexane, 1, 4- dioxane has been carried out at room temperature to understand the role of quenching mechanism. The Stern-Volmer plots have been found to be linear. As probability of quenching per encounter 'p' is less than unity, and the activation energy for quenching '$E_a$' is greater than the activation energy of diffusion '$E_d$', it is inferred that the fluorescence quenching mechanism is not due to material diffusion alone.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.965-970
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• 2003

This study has been performed to develope a method for the simultaneous determination of 1,4-dioxane (DOX), epichlorohydrin (EPC), propylene chlorohydrin (PCH), ethylene chlorohydrin (ECH) and 1,3-dichloro-2-pro-panol (DCP) in polysorbates, chloline chloride, choline bitartrate, modified starch and spices by purge and trapgas chromatography. Experimental design was used to select a suitable trap by measuring the limit of detection (LOD) and to investigate the effect of temperature and salt of extraction, and the percentage of recovery in various matrix. The LOD of DOX, EPC, PCH, ECH and DCP were 1.38$\mu\textrm{g}$, 0.23$\mu\textrm{g}$, 3.30$\mu\textrm{g}$, 3.97$\mu\textrm{g}$, 20.43$\mu\textrm{g}$ respectively, by means of using Vorcarb 3000 trap with 5$0^{\circ}C$ sample sparger. Excluding EPC, the recoveries of target compounds were above 90% in all matrix. Target compounds in polysorbates (17), choline chloride (5), choline bitartrate (5), modified starch (8) and spices (25) were not detected. But 2.5 ppm of DOX was detected in Tween 80.