• Journal of Korean Society for Atmospheric Environment
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• v.8 no.1
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• pp.38-44
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• 1992

In thisy study the quantities of the inorganic ions in the precipitation of the rural area of Choongbook Province are analyzed. The sampling period of the study was between February and June of 1991. Anion concentrations were determined by ion chromatography. Metal cation concentrations were analyzed by atomic absorption spectroscopy. Nessler's reagent was used for ammonium ion. The average pH of the rain was 4.6. Occasionally, however, acidic rain of pH 3.5 was found. The ratio of anion/cation was 0.57, where the concentrations of anion was much smaller than the same of the cation. This was attributed to the high concentrations of the ammonium ion. Ion concentrations were higher in February and March than other months. Also, it was found that the $2[SO_4^{2-} + [NO_3^-]-[NH_4^+]$ gave the highest correlation with the pH values.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1E
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• pp.24-28
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• 1997

Ultrasonic relaxation measurements for imidazole and its derivative in phosphate buffer exhibit a high peak of absorption at neutral pH. Near neutral pH, protolysis and hydrosis may be neglected and the essential reaction only consists of a direct proton-exchange. The kinetics constants and the volume changes for the proton transfer reaction with the protonated imidazole and 2-methylimidazole have been determined at 25℃. The kinetics constants are 7.2×108s-1M-1for imidazole and 1.7×108s-1M-1 for 2-methylimidazole. The kinetics constants are used to estimate the spectrum of relaxation times and acoustic relaxation amplitude associated with intermolecular and intramolecular proton-exchange reactions in bilogical media. It is concluded that the magnitude of the acoustic absorption reasonalbly attributable to the perturbation of proton-transfer equilibria between imidazole and inorganic phosphate is comparable in magnitude with the acoustic absorption observed in some intact tissues.

• Journal of Photoscience
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• v.11 no.32
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• pp.65-69
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• 2004

The mechanism of interaction of four coumarin derivatives (CDS) with bovine serum albumin (BSA) was studied using spectrofluorometric technique. It was found that the coumarin ring common to all CDS makes major contribution to interaction. Binding affinities could be related to parachor values of CDS. Stem-Volmer plots indicated the presence of static component in the quenching mechanism. Results also showed that both tryptophan residues of protein are accessible to CDS. The high magnitude of rate constant of quenching indicated that the process of energy transfer occurs by intermolecular interaction forces and thus CDS binding site is in close proximity to tryptophan residues of BSA. Binding studies in the presence of the hydrophobic probe, 8-anilino-l-naphthalein-sulfonic acid showed that there is hydrophobic interaction between CDS and the probe and they do not share common sites in BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CDS to BSA involve hydrophobic bonds predominantly. The effects of various metal ions on the binding of CDS with BSA were also investigated.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.66-67
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• 2012

As polymer coatings of nano-structured surface become significant to obtain functionalized materials, catechol derived from a mussel protein has attracted increasing attention for its universal adhesiveness. In addition to the unique adhesion property, its reducing ability of metal ions during oxidative polymerization to polydopamine (pD) widely expands the application of catechol molecules in the field of surface modification. In this study, we present the catechol conjugated smart polymer coatings for regulating surface properties such as wettability and anti-fouling effects. In additino, the in situ silver coating of electrospun polymer nanofibers using a silver-catechol redox reaction is presented as a simple method to produce metal nanostructures.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.237-246
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• 1988

The higher bacterial numbers on clay than on sand were caused by different environmental factors. Such factors affecting the adsorption of E. coli ATCC 11775 in the sediment as follows; optimal pH range for the adsorption of E. coli ATCC 11775 was pH 7.5-pH 9.5. E. coli ATCC 11775 were shown maxima in the salinity of 18.$75%_{o}$ on sand type sediment and $12.5%_{o}$ on clay type sediment. Bacteria attached better to clay typed sediment than to sand typed sediment when organic substance was eliminated. Beef extract of 0.5%-1% concentration was found to promote the attachment of E. coli ATCC 11775 effectively. Peptone of 0.5% was enganced the attachment on the clay, and peptone of 1.3%-5%, on the sand. E. coli ATCC 11775 was found to adsorb onto benthonite with the highest efficiency and on celite with the lowest efficiency. Efficiency of adsorption by inorganic ions was shown due to higher values of ion. Adsorption was achieved in the order of $Al^{3+}, Ca^{2+}, Na^{+}$.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1071-1077
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• 2003

The aim of this study is, firstly, to find out what kinds of inorganic species are produced in the photocatalytic oxidation of ammonium-nitrogen containing water and, secondly, to seek the influence of anion for the photocatalytic oxidation of ammonium contained compounds. The photoenergy above 3 eV(λ <415 nm) was effectively absorbed by TiO$_2$ and TiO$_2$/polymer was used to be oxidized NH$_4$-N in wastewater to NO$_3$-N. Existing the anion as Cl$\^$-/, the rate of photocatalytic oxidation decreased regardless of other condition. This result showed that the chloride ions reduced the rate of oxidation by scavenging oxidizing radical species as OH$\^$-/ and OCl$\^$-/. Some of the added ion might have blocked the active sites of the catalyst surface, thus deactivated the catalyst.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1262-1264
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• 1993

An amorphous $Se_{75}Ge_{25}$ thin film as inorganic resist for the focused ion beam lithography(FIBL) is investigated. This film offers an attractive potential alternative to polymer resists because of a number of advantages, such as the possibility of preparing physically uniform films of thickness as small as 200A and obtaining both positive and negative resist action in the same material, compatibility with dry processing, the sensitivity on optical, e-beam and ion beam exposure, the high-temperature stability, etc. In previous paper, the defocused ion beam-induced characteristics in a-$Se_{75}Ge_{25}$ film has been propose. Practically it is neccesary to know the relation with resist and source ions. For the purpose, the ion stopping power, the ion projected range and ion transmission coefficiency are studied. In this paper, the theoretically calculated values of parameters are presented and compared with theory.

• Membrane and Water Treatment
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• v.10 no.4
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• pp.299-305
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• 2019

Managed aquifer recharge (MAR) systems are gaining interest as an alternative to conventional water resources. However, when the water recovered in MAR systems, dissolved iron and manganese species may easily oxidize and they cause well screen clogging or require abandonment of extraction wells. In this study, both oxic and anoxic conditions were analyzed to verify the feasibility of the membrane filtration performance under various solution chemistries. The fouling mechanisms of the metal ions under anoxic conditions were also investigated by employing synthetic wastewater. The fouled membranes were then further analyzed to verify the major causes of inorganic fouling through SEM and XPS. The newly suggested anoxic process refining existing membrane process is expected to provide more precious information about nanofiltration (NF) membrane fouling, especially for demonstrating the potential advantages to chemical-free drinking water production for indirect potable reuse.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.9
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• pp.677-685
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• 2011

The reverse osmosis membrane processes have several operational problems. Fouling by inorganic scale occurs on membrane surface due to increases in concentrations over solubility by retaining ions on feed side of the membrane. Inorganic scales could be controlled by antiscalants or acid addition. In this study, three antiscalants having different characteristics were selected and evaluated on efficiency of $CaCO_3$ scale control. The $CaCO_3$ scale was inhibited by the antiscalants : 0.4 mg/L for SHMP, 0.6 mg/L for Spectra Guard, and 3 mg/L for Flocon 150 N. Increasing concentration factors of simulated sea water resulted in increases in antiscalant doses for the scale control. The increases in doses were positively proportional to the concentrate factors used in this study. Spectra Guard, one of the polyacrylate type antiscalants, was the most effective to control $CaCO_3$ scale. The antiscalants with the different scale inhibition time and doses implied the different control mechanisms.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.418-423
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• 2017

In hydroponics, the nutrient solution is supplied considering the water and nutrient uptake characteristics of crops. However, as the ionic uptake characteristics are changed as a result of the weather conditions or the growth response of the crops, the root zone can not be maintained in optimal condition. In addition, the coir substrate has been used mainly for the tomato cultivation in place of the inorganic substrate, there are few studies on long-term cultivation using coir substrate. Therefore, this study was conducted to investigate the effect of EC level of irrigation solution on tomato growth and inorganic ions of root zone in soilless culture using coir. Coir substrate mixed with 5 : 5 chip and dust was used. EC level of irrigation solution was 1.0, 1.5, 2.0, and $3.0dS{\cdot}m^{-1}$. At the initial stage, $NO_3-N$, P, Ca and Mg in the drainage were lower than the irrigation level at 1.0 and $1.5dS{\cdot}m^{-1}$. However, EC $2.0dS{\cdot}m^{-1}$ or higher, all the ions except P were highly concentrated in the drainage. The average fruit weight was not significantly different between 1.0 and $1.5dS{\cdot}m^{-1}$ until 3th cluster, but from the next cluster, the higher the EC level, the smaller the weight. The number of fruit and yield to 6th cluster was the highest at $1.5dS{\cdot}m^{-1}$. From the next cluster, The yield was decreased with the higher EC level. At the early stage of growth, BER occurred only in EC $3.0dS{\cdot}m^{-1}$, but increased in all treatments with increasing irradiation. The incidence rate of EC $3.0dS{\cdot}m^{-1}$ was higher than that of the lower EC level treatment.