• Economic and Environmental Geology
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• v.34 no.6
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• pp.539-553
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• 2001

Geochemical data of the Han river water, including four tributary water samples in the main Han river are presented in this paper. The concentration of dissolved ions in the North Han river water decreases in order of Ca>Na>K>Mg and HCO$_3$>NO$_3$>SO$_4$>Cl, which it mainly affected by the chemical weathering of granite and gneiss in the drainage basin. Meanwhile, the South Han river water shows a decreasing order of Ca>Mg>Na>K and HCO$_3$>SO$_4$>NO$_3$>Cl, which is controlled by the bed rock geology of carbornate rooks and the inflow of acid mine drainage from the metal and coal mines in the Taebaegsan and Hwanggangri areas. The main Han river waters are characterized by unusually high concentration of Na, Cl and SO$_4$ (Ca>Na>K>Mg and HCO$_3$>SO$_4$>CI>NO), indicating a significant anthropogenic pollution by human activities in the metropolitan Seoul city. The geochemical data of the Han river waters from 1981 through 1996 to 1999 records a significant increase in SO$_4$ and NO$_3$, which responsible for the increasing arid mane drainage and municipal anthropogenic pollution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.116-116
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• 2008

Cu CMP 공정시 높은 압력으로 인하여 low-k 유전체막에 손실을 주며, 디싱과 에로젼 같은 문제점을 해결하기 위하여 기존의 CMP에 전기화학을 결합시킴으로서 낮은 하력에서의 Cu 평탄화를 달성 할 수 있는 ECMP(Electrochemical Mechanical Polishing)기술이 필요하게 되었다. 본 논문에서는 $NaNO_3$ 전해액이 Cu 표면에 미치는 영향을 SEM (Scanning electron microscopy), EDS (Energy Dispersive Spectroscopy), XRD(X-ray Diffraction)를 통하여 전기화학적 특성을 비교 분석하였다.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.988-993
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• 2008

The characteristics of NO oxidation using sodium chlorite ($NaClO_2$) powder have been investigated by a flow type packed-bed reactor, where the reaction temperature and the space velocity are varied in the range of $20{\sim}230^{\circ}C$ and $0.4-2.2{\times}10^5hr^{-1}$, respectively, and the simulation gas mixtures are composed of NO (0~200 ppm), $NO_2$ (0-200 ppm), $O_2$ (0~15%) and $H_2O$ (0~15%) within $N_2$ balance. It has been found that the oxidation efficiency of NO depends greatly on the reaction temperature, exhibiting the existence of critical reaction temperature at about $170^{\circ}C$ where the oxidation efficiency of NO is maximized and then abruptly decreased with further increase of reaction temperature, resulting in being negligible over $190^{\circ}C$. Such a behavior in the oxidation efficiency has been originated from the phase transition of $NaClO_2$ at about $170^{\circ}C$ to form $NaClO_3$, and NaCl which are chemically inactive toward the oxidation of NO. The chemical reaction of NO with $NaClO_2$ has been observed to produce $NO_2$, ClNO and $ClNO_2$, whereas that of $NO_2$ only OClO species. Additionally, we have also observed that the introduction of $O_2$ and $H_2O$ has little influence on the oxidation of NO.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.451-457
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• 2000

Experimental investigations on the effect of two kinds of additives ; aqueous NaOH solution and ammonia(NH$_3$) for removal of NOx and SO$_2$ simultaneously by corona discharge were carried out. The simulated combustion flue gas was[NO(0.02[%])-SO$_2$(0.08[%])-$CO_2$-Air-$N_2$] Volume percentage of aqueous NaOH solution used was 20[%] and $N_2$flow rate was 2.5[$\ell$/min] for bubbling aqueous NaOH solution Ammonia gas(14.81[%]) balanced by argon was diluted by air. NH$_3$ molecular ratios(MR) based on [NH$_3$] and [NO+SO$_2$] were 1, 1.5 and 2.5 The vapour of aqueous NaOH solution and NH$_3$was introduced to the main simulated combustion flue gas duct through injection systems which were located at downstream of corona discharge reactor. NOx(NO+NO$_2$) removal rate by injecting the vapour of aqueous NaOH solution was much better than that by injecting NH$_3$however SO$_2$removal rate by injecting NH$_3$was much better than that by injecting the vapour of aqueous NaOH SO$_2$removal rate slightly increased with increasing applied voltage. When the vapour of aqueous NaOH solution and NH$_3$were simultaneously injection NOx and SO$_2$ removal rate were significantly increased.

• Analytical Science and Technology
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• v.14 no.2
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• pp.103-108
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• 2001

Rare earth elements(REE) were separated by solvent extraction with tri-n-butyl phosphate(TBP) and $NaNO_3$, followed by back extraction with water. The method was applied to the determination of REE to circumvent the spectral interferences of ICP-AES analysis. The effects of the $NaNO_3$ concentration and the addition of hydrophobic solvents on the extraction efficiencies were investigated. Increases of the $NaNO_3$ concentration enhanced the extraction efficiencies of REE, and more than 95% recoveries were obtained at 5M of $NaNO_3$ concentration. On the other hand, addition of hydrophobic solvents lowered the extraction efficiencies. The method was applied to determine the REE in the monazite sample. But the precisions of the analytical results were more than 20%.

• Journal of Powder Materials
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• v.13 no.4 s.57
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• pp.278-284
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• 2006

Spherical Ag powder was prepared in the system of $AgNO_3\;and\;NaBH_4$ by wet chemical reduction method. The size of Ag powder was increased as the reaction temperature and the concentration of reducing agent was decreased in the constant concentration of dispersion agent. Optimum conditions of producing Ag powder having $1.39{\mu}m$ of D50 was 1M of $AgNO_3$, 0.5M of $NaBH_4$, 1.5g of Gelatine in the room temperature.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.389-398
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• 1996

In order to understand the relative importance of various pathways leading to the production and transformation of aerosols under different atmospheric conditions, the behavior of atmospheric aerosols have been investigated using a high volume tape sample in Seoul for a week period during August 1990. The concentrations of anion $(SO^{2-}_4, NO^-_3, CI^-)$ and cation $(Ca^{2+}, Na^+, NH^+_4)$ species of aerosol samples were analyzed to identify the ionic composition of aerosols and to estimate their relative contributions to aerosol formation. The concentrations of aerosol species were calculated by a multiple regression model. The results of our calculations indicate the existence of various chemical species such as $(NH_4)_2SO_4, Na_2SO_4, CaSO_4, NH_4NO_3, NaNO_3, Ca(NO_3)_2, NH_4Cl$, and NaCl salts. According to our calculations, the most dominant species of aerosol was $(NH_4)_2SO_4$ with the mean concentration of 23.3 $/mu g/m^3$ (66.9%). The proportion of different componts with aerosol (e.g., $NH_4NO_3$ and $NH_4Cl$) was strongly affected by temperature, relative humidity, and partial presure of gases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.379-385
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• 1987

A field experiment was conducted to find out the effects of liming (soil pH) and sources of N on the chemical constituents of soil and leaf lamina of burley tobacco. Treatments consisted of liming (nonliming, liming to soil pH 5.5 and 6.5) as the main plot and N sources［compound fertilizer of containing 3.9% $NH_4-N$ and 6.1% $NH_2-N,\;NaNO_3,\;(NH_2)_2CO\;and\;(NH_4)_2SO_4$］as the sub-plot. The soil pH was high in $NaNO_2$ plot, while low in $(NH_4)_2SO_4$. But the differences of Ca concentration in top soil among N sources were not detected. The $NO_3-N$ concentration in top soil was high in high limed and $NaNO_3$ plot. The $NO_3-N$ content of leaf (lamina) at 75 days after transplanting was high in $NaNO_3$ plot and CaO con-tent of leaf at 45 days after transplanting was high in high limed plot. But neither liming nor N source had effect on the contents of total nitrogen, $P_2-O_{5}\;and\;K_2O$ of leaf during growing season. There was no significant differences in total alkaloid and total nitrogen contents of cured leaf (lamina) to liming and N source. But when the source of N was $NaNO_3$, the content of total alkaloid was increased by adding lime. When the source of N was $(NH_4$)_2SO_4$, the content of $K_2O$ in cured leaf was high while CaO was low. But neither liming nor N source had effect on the contents of $P_2-O_{5}$ and MgO in cured leaf.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.5
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• pp.210-213
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• 2011

Glass-ceramics composed of $5Na_2O-36CaO-10TiO_2-xP_2O_5$ could be obtained with $P_2O_5$ content as following procedure: 1) leaching out $Ca_3(PO_4)_2$ crystals between $Ca_3(PO_4)_2$ and $NaTi_2(PO_4)_3$ selectively in 1 N HCl solution for 2 days, and 2) exchanging $Na^+$ ion to $Ag^+$ ion in Ag($NO_3$) solution for 1 day. Scanning electron microscope (SEM) and X-rat diffractometer (XRD) were measured to verify the proper synthesis of glass-ceramics. And anti-bacteria test was accomplished using Staphylococus aureus bacteria. In the results of anti-bacteria test, the bacteria were died perfectly after 3 hours.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.187-200
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• 1990

The purpose of this study was to investigate antimicrobial effect of several irrigation solutions on 7 anaerobes and 2 aerobes, which are found frequently in infected root canals. The antimicrobial effects of normal saline, 3% $H_2O_2$, 0.5% & 3.5% NaOCl, 10% & 50% citric acid and mixed solutions of 3% $H_2O_2$ plus 3.5% NaOCl were compared. No. 80 paper points dipped in bacterial broth were soaked in each irrigation solutions and moved into thioglycolate broth, subcultured in agar plate for bacterial growth. The results were as follows: 1. Normal saline had no antimicrobial effect. 2. Mixed solutions of 3% $H_2O_2$ plus 3.5% NaOCl, 10% citric acid had relatively weak antimicrobial effect. 3.3% $H_2O_2$, 50% citric acid, 0.5% NaOCl showed relatively strong antimicrobial effect. 4. 3.5% NaOCl had the strongest antimicrobial effect among used 7 irrigation solutions.