• 한국해양학회지
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• v.13 no.1
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• pp.19-28
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• 1978

To estimate the chemical mass balance of several kinds of trace metals in sea water, suspended matter and bottom sediments, sixty samples from the Kum and Mankyung estuaries were analyzed. In both estuaries, the distribution patterns of leachabl suspended trace metals and of bottom sediments were established to be similar. The relationship between the metal concentration and clay content of the sediments was found to be such that the metal concentration increases with an increase in clay content. A linear correlation ws determined between pairs of leachable metals (Fe-Zn, Fe-Mn and Zn-Mn) in the Kum estuary. However, in the Mankyung estuary linear relationship does not exist. Finally, it is suggested that the trace metals are reworking in the Kum estuary and those in the Mankyung estuary are sinking.

• Journal of the Korean Electrochemical Society
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• v.7 no.1
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• pp.1-8
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• 2004

This paper deals with the recent development of high-voltage cathode materials of mono- and di- metal ions substituted spinel $LiMn_2O_4$ for lithium batteries. $LiCu_xMn_{2-x}O_4(0{\leq}x{\leq}0.5)$ shows reversible intercalation/deintercalation in two potential regions, $3.9\~43\;and\;4.8-5.0V$ and stable electrochemical cycling behavior but with low capacity. $LiNi_{0.5}Mn_{1.5}O_4$ obtained by a sol-gel process delivers a capacity of 127mAh $g^{-1}$ on the first cycle and sustains a value of 124 mAh $g^{-1}$ even after the 60th cycle. The $Li_xCr_yMn_{2-y}O_4(0{\leq}x{\leq}0.5)$ solid-solutions exhibit enhanced specific capacity, larger average voltage, and improved cycling behaviors for low Cr content. $LiCr_yMn_{2-y}O_4$ presents a reversible Li deintercalation process at 4.9V, whose capacity is proportional to the Cr content in the range of $0.25{\leq}x{\leq}0.5$ and delivers higher capacities. $LiM_yCr_{0.5-y}Mn_{1.5}O_4(M=Fe\;or\;Al)$ shows that the capacity retention is lowered compared with lithium manganate. The cumulative capacities obtainable with Al-substitutted materials are less than those with Fe-substituted materials. $LiCr_xNi_{0.5-x}Mn_{1.5}O_4(x=0.1)$ delivers a high initial capacity of 1$152mAh\;g^{-1}$ with excellent cycleability.

• Korean Journal of Materials Research
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• v.2 no.2
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• pp.126-132
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• 1992

Experiment has been performed to investigate the thermal and magnetic properties of Mn-ferrite by electrolysis. Using the 0.2%C mild steel as soluble anode and SUS 304 stainless steel as cathode, Mn-ferrite could be made from the sulfuric acid leaching of the wasted manganese dry cell and $MnSO_4$reagent by electrolysis. As the result of X-ray diffraction, thermal analysis and magnetic measurement, Mn-ferrite was the spinel type in $Mn_{x}Fe_{3-x}O_4$ (X=1), the weight loss rate of $Mn_{x}Fe_{3-x}O_4$ were linearly increased up to the $200^{\circ}C$. Ms, Mr and Hc values were decreased with increasing Mn content and heating temperature. When Mn-ferrite was formed by $MnCl_2$reagent electrolysis, Ms values were higher than those formed from the sulfuric acid leaching of the wasted manganese dry cell and $MnSO_4$reagent by electrolysis. In Mn-ferrite, which was formed from the sulfuric acid leaching of the wasted manganese dry cell by electrolysis, Ms and Mr values were higher, Hc values were lower than which was formed by $MnSO_4$ reagent electrolysis at $200^{\circ}C\;and\;300^{\circ}C, while the same values at $100^{\circ}C$. The shape of particles was spherical type, the sizes of them were about $0.1{\mu}m$ sub-micron in $MnSO_4$reagent electrolysis, $0.5{\mu}m$ in the sulfuric acid leaching of the wasted manganese dry cell by electrolysis.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.281-295
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• 2010

This paper deals with magnetic susceptibility, mineralogy, soil properties (pH, EC, CEC, loss on ignition), iron and manganese oxides, the content and partitioning of heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn), and their mutual relationship in the soil samples of an unpolluted, abandoned mine area, and industrial complex area. The various minerals derived from weathered bedrock were identified by X-ray diffraction in the unpolluted soil samples, except for the magnetic minerals. XRD analysis also revealed the existence of hematite and magnetite related to mine tailings and waste rocks in the abandoned mine area samples. The industrial complex area samples had carbonate minerals, such as calcite and dolomite, that might be due to anthropogenic deposition. The sum of the reducible, oxidizable, and residual fractions was over 80% for the abandoned mine area samples and over 50% for the industrial complex area samples using the sequential extraction method. The industrial complex area samples had a relatively high carbonate fraction that was associated with carbonate minerals. The content of aqua regia-extractable Fe, Mn, As, and Zn had a high positive correlation with the content of the dithionite-citrate-bicarbonate (DCB)-extractable method related to Fe/Mn oxide phases. The 54% and 58% of aqua regia-extractable Fe and As content, respectively, acted together with the concentrations of the DCB-extractable phases. Magnetic susceptibility values of total samples ranged from 0.005 to $2.131{\times}10^{-6}m^3kg^{-1}$. The samples including iron oxide minerals, such as hematite and magnetite, had a high magnetic susceptibility. The magnetic susceptibility showed a significant correlation with the heavy metals, Cd (r=0.544, p<0.05), Cr (r=0.714, p<0.01), Ni (r=0.645, p<0.05), Pb (r=0.703, p<0.01), and Zn (r=0.496, p<0.01), as well as Fe (r=0.608, p<0.01) and Mn (r=0.615, p<0.01). The aqua regia-extractable Fe and Mn content had a significant positive correlation with Cd, Cr, Cu, Ni, and Zn. However, the DCB-extractable Fe and Mn content had a significant positive correlation with As and Ni, indicating that the heavy metals were associated with Fe and Mn oxide minerals.

• Applied Biological Chemistry
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• v.29 no.2
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• pp.227-236
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• 1986

Three types of Kochujang(soybean-red pepper paste) were prepared with glutinous rice flour (group A), glutinous rice grain (group B) or the mixture of flour and grain (group C) to investigate some chemical composition, enzyme activities and the texture during aging period. 'There were no remarkable differences in the contents of moisture, crude protein, crude fat, minerals and alcohols, titrable acidity and pH among the tested groups. Amino nitrogen content, acidic protease and saccharogenic amylase activities were measured to be higher values for group A whereas reducing sugar content higher values for group B. All tested groups contained Ca, Cu, K, Mn, Mg, P and Fe, particularly higher amount of K but a trace of Cu, Mn and Fe. All tested groups showed higher content of aspartic acid, glutamic acid, cystine, proline and lower content of histidine and valine 60 days after the preparation. The total free amino acid content was 16.49 mg/g for group A, 13.68 mg/g for group B and 15.84 mg/g for group C. The measurement of texture showed high values of hardness and adhesiveness with group A immediately after the preparation and with group B at the end of aging. Cohesiveness and springiness were high with group A while low with group B throughout aging period.

• Korean Journal of Medicinal Crop Science
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• v.1 no.2
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• pp.171-177
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• 1993

This experiment was conducted to select and rear the adaptable cultivar which isused for various purpose and to build a year-round cultivation using with characters of aerial part and analysis of chemical components in 28 local cultivar of Artemisia princeps Var. The growth of aerial part, which are stem length, stem diameter, no. of branch, node, leaf size and leaf pubescence, in north local cultivars was more vigorous than those of south local caltivars. Fresh weight of "Myeongcheonssuk " was highest in local caltivars, and in view of local area, local cultivars which was collected from Iri Si and Euiseong Gun was shown the highest fresh weight. Local cultivars as mentioned above had a characters with plenty of leaves, nodes and pubescence of leaf is long. In chemical components of leaves in morth cultivar, content of N, MgO, Zn, Cu, Mn was high, while $P_2O_5,\;K_2O$ in middle local cultivars, Fe in south local cultivars. The more content of carbohydrate in leaves was high, the content of $K_{2}O$ had a increasing tendency. In local cultivars which was collected form Iri Si and Euiseong Gun with the highest fresh weight, content of $N,\;P_{2}O_5,\;K_{2}O$ was high, on the other hand content of MgO, Zn, Ca, Mn, Fe, was low in leaves of Artemisia Princeps Var.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05a
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• pp.2-2
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• 1992

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.506-508
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• 2001

The ferrite plating with applying power ultrasound waves of 19.5 kHz and 600W enabled us to encapsulate entirely MnZn ferrite cores for transformers with Ni$\sub$x/Zn$\sub$y/Fe$\sub$3-x-y/O$_4$coating. Supplying a NH$_4$OH solution during the plating broke the limit of the solubility of Ni ions to ferrite-plated films. The electrical resistivity of the NiZn ferrite coating increased with increasing the Ni and Zn content, reaching 2.3${\times}$10$\^$5/Ωcm at the composition of Ni$\sub$0.24/Zn$\sub$0.30/Fe$\sub$2.46/O$_4$. The saturation magnetization was 540 emu/㎤. As a result, the MnZn ferrite cores were successfully encapsulated with the NiZn ferrite coatings for an insulation layer.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.103-106
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• 2012

To investigate distribution characteristics of heavy metals in soils in the vicinity of King Sejong Station of King George Island, Antarctica, Fe, Mn, Cu, Zn, Pb, Co, Cd, Cr, Ni and Mo contents were investigated under different distances and directions from King Sejong Station. 13 sample sites were distributed from King Sejong Station. In site 4, the Cd content was higher than that in other sites. The Cr content was the highest in site 9, and the Ni and Mn contents were high in site 12. Cu, Co and Zn were highly contained in distance 1~2 km from King Sejong Station. Cd, Cr, Ni and Mo contents were lower, whereas Fe, Mn, Cu, Zn, Pb and Co contents were higher than other heavy metal contents at all sites.

• Journal of the korean society of oceanography
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• v.32 no.3
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• pp.120-127
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• 1997

Depositional environment off the Shihwa Dam has been studied to investigate the change of sedimentation process and the pollution. In order to understand how the sediments are distributed, polluted and modified, depositional factors have been analyzed and compared with the previous data. Study area, located off the Shihwa Dam, was surveyed to collect 25 bottom samples and 2 cores in 1996 and echo-sounding in 1997. These sediments were analyzed for the study of the global characteristics of sediment such as grain size and organic matter. Among these samples, the selected twenty surface sediments were analyzed for the comparison with their contents of metallic elements (Al, Mn, Fe, V, Cr, Co, Ni, Cu, Zn, Cd, Pb, As). According to field and lab analysis of sediments, three sedimentological zones have been generally identified around study area; near the dam (sandy Silt), near the dike (Sand) and offshore (silty Sand) zones. Textural parameters show that the content of silt and clay is dominant near the dam excepting the dike zone of LNG Storage Base and offshore (Palmido). The total concentration of Mn, Ni, Fe, Zn and Cd in bulk sediments was increased after the construction of the dam, while the content of Mn and Cr were higher near tidal channel than in the offshore area. Meanwhile, the annual increasing pattern of some heavy metal has appeared in this area. Based on this primary study, modification of the depositional environment may be caused by the construction of the dam and LNG Storage Base. Additionally, environmental evaluation on organic/inorganic factors has been suggested for interpreting environmental changes caused by coastal development in the nearshore such as the Shihwa coastal area.