• Journal of Soil and Groundwater Environment
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• v.15 no.2
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• pp.10-17
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• 2010

Advanced oxidation processes (AOPs) have advantages to reduce the processing time and mineralize contaminants dissolved in groundwater. Recently, remediation techniques for organic contamination in groundwater have been studied, and technology using $UV/H_2O_2$ is generally accepted as one of the most powerful and reliable alternative for the remediation of groundwater contamination. In this study, $UV/H_2O_2$ technology, which generates hydroxyl radical ($\cdot$ OH) as known for strong non-selective oxidant, was used to degrade chlorinated solvents (TCE and PCE), and it was expanded to apply continuous stirred tank reactor (CSTR) system (i.e. combinations of three CSTR). The tested parameters for CSTR system were retention time and groundwater/$H_2O_2$ injection volume ratio. To find optimum parameters for CSTR system, various retention time (6 min ~ 90 min) and groundwater/$H_2O_2$ injection volume ratio (5/1 ~ 119/1) were tested. Other conditions for CSTR were adapted from the batch test results, which concentration of $H_2O_2$ and UV dose were 29.4 mM (0.1%) and 4.3 kWh/L, respectively. Based on the experimental results, the optimum parameters for CSTR system were 20 min for retention time and 119/1 for groundwater/$H_2O_2$ injection volume ratio. Applying these optimum conditions, chlorinated solvents (TCE and PCE) were removed at 99.9% and 99.6%. Moreover, the effluent concentrations of TCE and PCE are 0.036 mg/L and 0.087 mg/L, respectively, which are satisfied the regulatory level (TCE 0.3 mg/L, PCE 0.1 mg/L). Consequently, the CSTR system using $UV/H_2O_2$ technology can achieve high removal efficiency in the event of treatment of groundwater contaminated by chlorinated solvents (TCE and PCE).

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.1040-1052
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• 2023

The objective of this study was to investigate the protective effects of functional nutrients including various functional amino acids, vitamins, and minerals on chicken intestinal epithelial cells (cIECs) treated with oxidative stress. The cIECs were isolated from specific pathogen free eggs. Cells were exposed to 0 mM supplement (control), 20 mM threonine (Thr), 0.4 mM tryptophan (Trp), 1 mM glycine (Gly), 10 μM vitamin C (VC), 40 μM vitamin E (VE), 5 μM vitamin A (VA), 34 μM chromium (Cr), 0.42 μM selenium (Se), and 50 μM zinc (Zn) for 24 h with 6 replicates for each treatment. After 24 h, cells were further incubated with fresh culture medium (positive control, PC) or 1 mM H₂O₂ with different supplements (negative control, NC and each treatment). Oxidative stress was measured by cell proliferation, whereas tight junction barrier function was analyzed by fluorescein isothiocyanate (FITC)-dextran permeability and transepithelial electrical resistance (TEER). Results indicated that cell viability and TEER values were less (p < 0.05) in NC treatments with oxidative stress than in PC treatments. In addition, FITC-dextran values were greater (p < 0.05) in NC treatments with oxidative stress than in PC treatments. The supplementations of Thr, Trp, Gly, VC, and VE in cells treated with H₂O₂ showed greater (p < 0.05) cell viability than the supplementation of VA, Cr, Se, and Zn. The supplementations of Trp, Gly, VC, and Se in cells treated with H₂O₂ showed the least (p < 0.05) cellular permeability. In addition, the supplementation of Thr, VE, VA, Cr, and Zn in cells treated with H₂O₂ decreased (p < 0.05) cellular permeability. At 48 h, the supplementations of Thr, Trp, and Gly in cells treated with H₂O₂ showed the greatest (p < 0.05) TEER values among all treatments, and the supplementations of VC and VE in cells treated with H₂O₂ showed greater (p < 0.05) TEER values than the supplementations of VA, Cr, Se, and Zn in cells treated with H₂O₂. In conclusion, Thr, Trp, Gly, and VC supplements were effective in improving cell viability and intestinal barrier function of cIECs exposed to oxidative stress.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.129-135
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• 2005

In this study, we have analyzed the removal efficiencies of $SO_2$ and $SO_2/NO$ by the pulsed corona discharge process and investigated the effects of several process variables on those removal efficiencies systematically. The effects of process variables such as applied voltage, pulse frequency, residence time, and initial concentrations of reactants (NO, $SO_2$, $NH_3$, $H_2O$, and $O_2$) on the removal efficiency were analyzed. As the applied voltage, the pulse frequency or the residence time increases or as the $O_2$ or the $H_2O$ or the $NH_3$ concentration in the inlet feed gas stream increases, the $SO_2$ removal efficiencies and the simultaneous removal efficiencies of $SO_2/NO$ also increase. These experimental results can be used as a basis to design the pulsed corona discharge process to remove $NO_x$ and $SO_x$.

• Korean Journal of Materials Research
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• v.1 no.2
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• pp.71-76
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• 1991

The superconducting powders in $YBa_2Cu_3O_{7-x}$ and Bi-Pb-Sr-Ca-Cu-O system were easily prepared from water in oil type emulsion by loading each cation into the aqueous phase. In $YBa_2Cu_3O_{7-x}$ system, the superconducting orthorhombic phase was formed by calcining at $750^{\circ}C$ for 10h in $O_2$. The size of the superconducting phase powders was submicron. The density of the sintered specimen using this powders was about 95% of the theoretical density and the resistance sharply decreases at about 90K, In Bi-Pb-Sr-Ca-Cu-O system the low Tc phase($(Bi, Pb)_2Sr_2Ca_1Cu_2O_y$) was formed by calcining at $800^{\circ}C$ for 10h in a low oxygen partial pressure of 1/20 atm The shape of clacined powder is thin plate of which size is about $2\mu\textrm{m}$ and thickness is smaller than $\mu\textrm{m}$. It was observed that the high Tc phase ($(Bi, Pb)_2Sr_2Ca_2Cu_3O_y$) was formed by sintering at $850^{\circ}C$ for 30h in oxygen pressure of 1/20 atm without intermediary grinding. The above sintered sample exhibited superconductivity with a Tc(zero)=105K.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.492-499
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• 2017

Combined treatment with gaseous and aqueous chlorine dioxide ($ClO_2$) was performed to improve the microbiological safety and quality of paprika. A single treatment of 50 ppmv $ClO_2$ gas for 30 min decreased the populations of Escherichia coli O157:H7 and Salmonella Typhimurium by 2.33 and 2.91 log CFU/g, respectively. In addition, a single treatment of aqueous $ClO_2$ (50 ppm) for 5 min decreased these populations by 1.86 and 1.37, respectively. The most dramatic effects were achieved by combined treatment of 50 ppm aqueous and gaseous $ClO_2$ for 30 min, which decreased populations of E. coli O157:H7 and S. Typhimurium by 4.11 and 3.61 log CFU/g, respectively. With regard to the qualities of paprika, no adverse effects were elicited by the combined treatment. Thus, combined treatment with aqueous and gaseous $ClO_2$ is a suitable approach that can be used to improve the microbial safety and quality of paprika.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1774-1780
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• 2008

New PVC based polymeric membrane electrodes (PME) and coated glassy carbon electrodes (CGCE) based on synthesized Schiff base complexes of Co(III); [Co(Salen)$(PBu_3)_2$]$ClO_4$, [Co($Me_2$Salen)$(PBu_3)_2$]$ClO_4$, [Co(Salen)$(PBu_3)H_2O$]$ClO_4$; as anion carriers for potentiometric determination of $ClO_4\;^-$were studied. The PME and also CGCE electrodes prepared with [Co(Me2Salen)$(PBu_3)_2$]$ClO_4$ showed excellent response characteristics to perchlorate ions. The electrodes exhibited Nernstian responses to $ClO_4\;^-$ ions over a wide concentration range with low detection limits ($1.0 {\times} 10^{-6}\;mol\;L^{-1}$ for PME and $9.0 {\times} 10^{-7}\;mol\;L^{-1}$ for CGCE). The electrodes possess fast response time, satisfactory reproducibility, appropriate lifetime and, most importantly, good selectivity toward $ClO_4\;^-$ relative to a variety of other common inorganic anions. The potentiometric response of the electrodes is independent of the pH in the pH range 2.5-8.5. The proposed sensors were used in potentiometric determination of perchlorate ions in mineral water and urine samples. The interaction of the ionophore with perchlorate ions was shown by UV/Vis spectroscopy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1768-1774
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• 2008

The particulate behaviors of nickel ferrite were investigated under the simulated PWR shutdown chemistry conditions. Temperature of the simulated water with concentration of 0.1 ppm Li and 2,000 ppm B was dropped from $300^{\circ}C$ to $150^{\circ}C$ with a rate of $0.625^{\circ}C/min$ and then constantly maintained at $150^{\circ}C$ under the pressure of 2,500 psi. The on-line particle counting and the concentration measurement of nickel dissolved were performed under 5, 15 and 25 cc/kg $H_2O$ dissolved hydrogen. Experimental results showed that total particle count in the simulated water was not greatly changed for three hydrogen concentrations as temperature was decreased. However, particles were smaller as temperature was decreased and then maintained constantly. The degree of variation in particle size distribution was greater at 15 cc/kg $H_2O$ dissolved hydrogen than any other dissolved hydrogen concentrations. Concentration of nickel ion was increased as temperature was decreased and was higher at 15 cc/kg $H_2O$ dissolved hydrogen than any other dissolved hydrogen concentrations. Theses results show that nickel ferrite is unstable with temperature variation and at dissolved hydrogen concentration of 15 cc/kg $H_2O$.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.600-606
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• 2018

The influence of acidity in MTT zeolite of different Si/Al molar ratio's on the catalyst activity in methanol-to-olefin (MTO) reaction has been investigated. The Si/Al ratio was controlled with the Al content in the gel when N,N,N',N'-tetramethyl-1,3-diaminopropane was used as a structure directing agent (SDA). The gel composition was controlled to $20SiO_2$ : 30SDA : x (=0.25~1.25)$NaAlO_2$ : 2NaOH : $624H_2O$, which was subject to the hydrothermal synthesis at 433 K for 4 days. As the composition of sodium aluminate decreased, the particle size of MTT zeolite increased, and also the amount of acid sites decreased. To investigate the catalytic performance, MTO reaction was carried out at 673 K with $1.2h^{-1}$ WHSV. It was found that the H-MTT (1.00Al) catalyst with a Si/Al molar ratio of 24 maintained the methanol conversion over 90% for 900 min.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.2
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• pp.287-293
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• 2015

This research verifies stainability, super bacteria antibacterial features and antibiotic resistance of Ulmus davidiana var. japonica Nakai (UD) extract in dye cotton cloth. UD was extracted with hot water, the test cloth dyed, and then processed by mordanting treatment using $FeSO_4$ $7H_2O$, $CuSO_4$ $5H_2O$ and $Al_2(SO_4)_3$. The surface color and color fastness of the three kinds (original cloth, the cloth without mordancy and mordant cloth) were measured and the influence of dying of cotton cloth and the mordant method on the genesistasis of Methicillin-resistant Staphylococcus aureus (MRSA), antibiotic resistant bacteria. 1. The surface color of the cotton cloth for dyeing (without and with mordancy) displayed a reddish and yellowish color. Stainability was greatest when the mordant of $FeSO_4$ $7H_2O$ was used. 2. When a mordant was not used for dyeing, the color fastness to washing, perspiration and friction of the contaminated cloth was satisfactory at 4 to 5 grade in general. 3. As for the antibiotic effect to super bacteria, the growth of germ was meaningfully suppressed both on the cloth without and with mordancy compared to the comparison cloth; in addition, the dyeing method with the biggest antibacterial impact was found to be the mordancy with the mordant of $CuSO_4$ $5H_2O$ after dyeing. The results of the experiments that involved dyeing with UD extract showed that cotton cloth processed through mordancy with the mordant of $CuSO_4$ $5H_2O$ had the biggest antibiosis to super bacteria and that processed with the mordant of $FeSO_4$ $7H_2O$ had the greatest stainability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.501-504
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• 2003

In this paper, for enhancement of property on a-Si:H TFTs We measure interface characteristics of ferroelectrics thin film and a-Si:H thin film. First, SrTiO$_3$ thin film is deposited bye-beam evaporation. Deposited films are annealed for 1 hour in N2 ambient at 150$^{\circ}C$ ∼ 600$^{\circ}C$. Dielectric characteristics of deposited SrTiO$_3$ films are very good because dielectric constant shows 50∼100 and breakdown electric field are 1∼1.5MV/cm. a-SiN:H,a-Si:H(n-type a-Si:H) are deposited onto SrTiO$_3$ film to make MFNS(Metal/ferroelectric/a-SiN:H/a-Si:H) by PECVD. After the C-V measurement for interface characteristics, MFNS structure shows no difference with MNS(Metal/a-SiN:H/a-Si:H) structure in C-V characteristics but the insulator capacitance value of MFNS structure is much higher than the MNS because of high dielectric constant of ferroelectrics.