• Proceedings of the Korean Magnestics Society Conference
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• 1991.05a
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• pp.73-74
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• 1991

The films with ferromagnetic fine particles dispersed in nonmagnetic matrix, such as $Fe-Al_2O_3$ and Fe-Cu have been studied for use of magnetic recording medium, optically device and sensor. Their magnetic properties depend strongly on structural parameter such as size and volume fraction of ferromagnetic particles. Fe-Cr-Ni alloy sputtered films also have microstructure with ferromagnetic -- b.c.c phase and nonmagnetic f.c.c phase grains. Magnetic properties of these films depend strongly on such a unique structure. These are depend on the ratio in volume of ferromagnetic particles to nonmagnetic ones $V_F/V_N$, the saturation magnetization Ms increased with increase of $V_F/V_N$. The coercivity Hc of the as-deposited films took maximum value of about 200 Oe at adequate $V_F/V_N$ and then Ms and Squareness S were 500 emu/cc and 0.5, respectively.(omitted)

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.120-122
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• 2002

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.61-66
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• 1998

An artificial zeolite was synthesized from bituminous coal fly ash by thermo-alkali treatment, $100{\pm}3^{\circ}C$ and 3.5 N NaOH solution for 24 hours, to develope new useful material in waste water treatment system. The artificial zeolite had much higher cation exchange capacity, $299cmol^+\;kg^{-1}$ and lower concentration of extractable heavy metals than bituminous coal fly ash. The higher the temperature and the longer the shaking time, the more Zn, Cu, Cd and Pb were sorbed chemically by the artificial zeolite. Shaking artificial zeolite and wastewater at $35^{\circ}C$ for 9 hours, the amount of sorbed heavy metals were $123.5g\;kg^{-1}$ for Zn, $164.7g\;kg^{-1}$ for Cu, $184.4g\;kg^{-1}$ for Cd and $350.6g\;kg^{-1}$ for Pb, respectively.

• 한국해양학회지
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• v.30 no.5
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• pp.371-381
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• 1995

To investigate the concentrations and transport patterns of particulate metals in river suspended matters, eighteen samples were collected from a fixed station located in the upper part of the Keum River through one year, and analysed for major elements (AI, Fe, P, Mn) and trace elements (Cr, Co, Ni, Cu, Zn, Cd, Pb, U). The contents of metals in suspended particulate matters (SPM) varied greatly with season and SPM load; maximum value in winter with low SPM level and minimum value in flood period and in spring Yangtze SPMs. The different trace metal level between rivers of Korea and China may be caused by the different geology of drainage basin(U) and by the different extent of anthropogenic input (Mn, Pb). Most of all particulate metals (>70%) except Mn, P and Cd were transported in the flood period with high water discharge and high suspended load. The magnitude of each transport phase (dissolved, non-detrital and detrital metals) was compared. The portions of labile metals (dissolved plus non-detrital metals) in the aquatic environment were in the range of 50%(Co) to 92%(Mn) of total metal transport and in the rank of Mn>Cd, U>Cu>Zn>Ni>Pb>Co.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.276-284
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• 2000

Distributions of organic carbon (Co$_{org}$), organic nitrogen (N$_{org}$), and heavy metals (Zn, Pb, Cr, Cu, Mn) were investigated in Lake Shihwa sediments. Surface and core samples were collected in April and September, 1997 and March, 1998 for the study. The results show that these components contents are variable with sampling timeand station. In surface sediments, both Co$_{org}$ and N$_{org}$ have similar distribution pattern in which their high contents found in stations located near the land, indicating that the streams and industrial wastes seem to act as point sources. The C$_{org}$ contents are linearly related with those of heavy metals. It appears, therefore, that the distribution of heavy metals may be partly controlled by a complex interplay of biogenic, terrestial, and anthropogenic factors. The C/N ratios from three stations are in the range of 3-32, with an average of 13.2. Vertical profiles of heavy metals in sediment cores are similar to those of C$_{org}$ and N$_{org}$. Copper content of sediments is enriched compared to that of reported value before dike construction, but Zn and Mn are not deposited considerably. Especially, Pb content show less variable. Currently, anthropogenic effects of industrial complex may not reached to drainage gate area where heavy metal contents are comparable with those adjacent to coastal sediments.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.291-295
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• 1998

Changes of chemical components and natural supplies by precipitation at agricultural zone in Chinan area of Chonbuk province from May 1, 1997 to April 30, 1998 were investigated. pH of precipitation ranged $6.44{\sim}7.24$ and EC showed $14.23{\sim}30.67{\mu}S/cm$. The $total{\sim}N$, NH4-N and NO3-N were $1.43{\sim}10.14$, $0.57{\sim}4.39$, and $0.18{\sim}1.69㎎/L$ respectively. The content of total-P showed $0.015{\sim}0.087㎎/L$ but ortho-P was not detected. The content of suspended solid, $Ca^{++}$, $Mg^{++}$, $Na^+$ and $K^+$ showed $3.6{\sim}15.3$, $0.37{\sim}1.66$, $0.17{\sim}0.52$, $0.22{\sim}0.87$, and $0.17{\sim}0.58㎎/L$. The content of SO42- and Cl- showed $3.37{\sim}014.47㎎/L$ and $1.02{\sim}7.24㎎/L$ respectively. Only Cu and Zn of heavy metals were detected $0{\sim}0.019㎎/L$ and $0.009{\sim}0.098㎎/L$ but Cd, Cu, Ni and Cr were not detected. Natural supplies of chemical components were 39.48㎏/ha/yr of total-N, 21.82㎏/ha/yr of $NH_4-N$, 6.90㎏/ha/yr of $NO_3-N$ and 0.68㎏/ha/yr of total-P. Also $Ca^{++}$, $Mg^{++}$, $Na^+$, $K^+$, $SO_4^{2-}$ and $Cl^-$ were supplied 14.46, 5.00, 7.26, 5.46, 98.76 and 31.16㎏/ha/yr respectively. Only of heavy metals were supplied 0.024㎏/ha/yr of Cu and 0.044㎏/㏊/yr of Zn.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.197-204
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• 1999

The extent of heavy metal pollution in agricultural in soils near the abandoned mine land site was investigated using their concentrations from the 47 sampling sites in B mine. Samples were prepared using 0.1N HCI - Korean Standard Methods - and then analysed for Cd, Cu, Pb, As and Cr by Inductively Coupled Plasma Spectrometer. In addition, soil and mine tailing samples were sequentially extracted to investigate the chemical speciation of heavy metals in them. The soils in the vicinity of mining area are highly contaminated by heavy metals ranging up to 5.96mg Cd/kg, 253.3mg Cu/kg, 76.7mg Pb/kg, and 15.45 mg As/kg, according to the analysis of Korean Standard Methods. The heavy metal levels by the sequential extraction are much higher than its level by Korean Standard Methods, and little correlated with each other. Based on the results, it is suggested that the As pollution in agricultural soils near the AMLS should be dealt as of prior significance in establishing reclamation strategies for the area.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.291-295
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• 2002

We measured the concentrations of heavy metals and VOCs in groundwaters (N=38) in Seoul. The comparison of our data with U.S. Environmental Protection Agency's Maximum Contaminant Levels for Drinking Water and with the Korean Drinking Water Standards shows that most of the metals except for Fe and Mn do not exceed the levels. However, the concentrations of most heavy metals (esp., Zn, Cu, Cr, Ni) tend to increase in residential and industrialized areas. The examination of the metal speciation using Anodic Stripping Voltammetry (ASV) and TOC analyzer Indicates that large amounts of Zn occur as labile metal fraction, whereas Cu occurs as non- labile forms at many sites, possibly due to its tendency to be adsorbed onto inorganic colloidal particles to form electroinactive species in groundwater. The most frequently existed VOCs in Seoul groundwaters are trichloroethylene and tetrachloroethylene, especially in agricultural, industrial, and high traffic areas.

• Journal of Korea Soil Environment Society
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• v.5 no.2
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• pp.67-85
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• 2000

Fifty seven soil samples were collected from the paddy soil filled with tailings in the vicinity of the Seosung Pb-Zn mine. Those samples were analyzed for As, Cd, Co, Cr, Cu, Pb, and Zn in order to investigate heavy metal pollution levels in the paddy soil. Analyses of the soil samples were carried out using Inductively Coupled Plasma Atomic Emission Spectrometry(ICP-AES) . Paddy soils show pH range from 6.55 to 8.26. X-ray diffraction analyses of the paddy soil indicate that the soils consist predominantly ankerite, siderite, quartz, mica, and clay minerals with minor amounts of amphibole and chlorite. The mineral composition of the waste rocks consists of massive galena, sphalerite, and minor amounts of pyrite, arsenopyrite, chalcopyrite, calcite, siderite, Pb-sulfosalt, and marcasite. The paddy soils were significantly contaminated by heavy metals(average concentrations, As: 334.4 ppm, Cd: 37.6 ppm, Co: 15.7 ppm, Cu: 214.1 ppm, Pb: 4,612 ppm, and Zn: 4,468 ppm).

• Environmental Engineering Research
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• v.12 no.1
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• pp.1-7
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• 2007

Most of the herb residue producing from oriental medical clinics(OMC) and hospitals(OMH) is wasted in Korea. To develop of adsorbent for removing heavy metal from wastewater, the various pre-treatment methods of the herb residue were evaluated by potentiometric titration, Freundlich isotherm adsorption test and the kinetic adsorption test. The herb residue was pre-treated for increasing the adsorption capacity by cleaning with distilled water, 0.1 N HCl and 0.1 N NaOH and by heating at $370^{\circ}C$ for 30 min. It showed a typical weak acid-weak base titration curve and a short pH break like commercial activated carbon during photentiometric titration of pre-treated herb residue. The log-log plots in the Freundlich isotherm test were linear on the herb residue pre-treated with NaOH or HCl like commercial activated carbon. The adsorption capacity(qe) in the Freundlich isotherm test for $Cr^{6+}$ was 1.5 times higher in the pre-treated herb residue with HCl than in activated carbon. On the other hand the herb residue pre-treated with NaOH showed the good adsorption capacities for $Pb^{2+}$, $Cu^{2+}$ and $Cd^{2+}$ even though those adsorption capacities were lower than that of activated carbon. In kinetic test, most of heavy metals removed within the first 10 min of contact and then approached to equilibrium with increasing contact time. The removal rate of heavy metals increased with an increase of the amount of adsorbent. Likewise, the removal rates of heavy metals were higher in the herb residue pre-treated with NaOH than in that pre-treated with HCl. The adsorption preference of herb residues pre-treated with NaOH or HCl was $Pb^{2+}>Cu^{2+}$ or $Cd^{2+}>Cr^{6+}$ in the order. Conclusively, the herb residue can be used as an alternative adsorbent for the removal of heavy metals depending on pr-treatment methods.