• Journal of Environmental Science International
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• v.1 no.2
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• pp.71-79
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• 1992

Selective extraction procedure has been used to quantify copper and cadmium In association with the various phases of aquatic sediment such as exchangeable/adsorbed, carbonate, manganese oxides, organic matter and iron oxides. Changes of pH influenced on the partitioning of copper in carbonate and exchangeable/ad- sorbed phases and of cadmium in carbonate phase of aquatic sediment. Addition of NTA and EDTA, copper and cadmium associated with carbonate phase were released from sediment to water. Total partitioning coefficient was 8.361 for copper and 0.497 for cadmium. The relative binding strengths of copper and cadmium to each solid phase can be ranked by using the partitioning coefficints. For copper it was observed that carbonate > organic matter > exchangeable/adsorbed > manganese oxides > iron oxides and for cadmiunm it was observed that exchangeable/adsorbed > carbonate > manganese oxides > organic matter > iron oxides.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.1-8
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• 2012

The effects of several factors including organic pigment blending and calending conditions on the surface and optical properties of coated paper were investigated. When clay and calcium carbonate are blended in the ratio of 7 to 3, highest smoothness and relative sediment volume were obtained. When organic pigments were added to the mixture of clay and calcium carbonate, the relative sediment volume did not changed significantly. However, when organic pigments were added to calcium carbonate, sheet gloss and smoothness were improved, and showed the better results than that obtained from the mixture of organic pigment and clay. When organic pigment is blended with clay, the particles of organic pigment are buried in the packing structure of coating layer. However, the particle shape of calcium carbonate is quite different from that of clay, and the aspect ratio of calcium carbonate is similar to that of organic pigment. Thus organic pigment particles are not buried and improved effectively the physical characteristics of coating layer. When the hollow sphere pigment was blended, opacity and sheet gloss were improved significantly. Even though the coating color applied was reduced, the similar level of opacity was maintained. Also, if particle size and void volume are increased, gloss is improved, because coating layer is easily transformed in calendering. Therefore, even though lower pressure was applied during calendering, the smoothness of surface of coating layer was improved, and the decrease of void volume in coating layer was reduced, and the quality of coated sheet can be improved.

• Geomechanics and Engineering
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• v.7 no.6
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• pp.649-663
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• 2014

In past few years, the use of bacterial calcium carbonate precipitation (biocementation) has become popular as a ground improvement technique for sandy soil. However, this technique was not applied to organic soil. This study focused on bacterial calcium carbonate precipitation and its effect on permeability in organic soil. A special injection system was prepared for inducing bacterial solution to the samples. The bacterial solution supplied to the samples by gravity for 4 days in specific molds designed for this work. Calcite precipitation was observed by monitoring pH value and measuring amount of calcium carbonate. Change in the permeability was measured before and after biocementation. The test results showed that the pH values indicates that the treatment medium is appropriate for calcite precipitation, and amount of precipitated calcium carbonate in organic soil increased about 20% from untreated one. It was also found that the biocementation can be considered as an effective method for reducing permeability of organic soil. The results were supported by Scanning electron microscopy (SEM) analysis and energy-dispersive x-ray (EDX) analysis.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.466-470
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• 2014

In this paper, organic solvent electrolytes were prepared by a mixture of propylene carbonate (PC), dimethyl carbonate (DMC), tetraethylammonium tetrafluoroborate ($TEABF_4$)s to evaluate the ionic properties of propylene carbonate (PC)/dimethyl carbonate (DMC) mixtures as solvents for a capacitor application, in view of improving the electrochemical performances. The bulk resistance and interfacial resistance of the mixture electrolytes were investigated using an AC impedance method. The morphology of carbon-based electrodes which were contained in different electrolytes was analyzed by scanning electron microscopy (SEM) method. From the experimental results, by increasing the FEC content, capacitance of electrodes was increased, and the interfacial resistance was decreased. In particular, by a content of 2 vol % FEC in 0.2 M $TEABF_4$ PC/DMC solvent, the electrolyte showed the superior capacitance. However, when FEC content exceeds 2 vol %, the capacitance was decreased and the interfacial resistance was increased.

• Carbon letters
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• v.16 no.1
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• pp.51-56
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• 2015

Carbonate-type organic electrolytes were prepared using propylene carbonate (PC) and dimethyl carbonate (DMC) as a solvent, quaternary ammonium salts, and by adding different contents of 1-ethyl-3-methyl imidazolium tetrafluoroborate ($EMImBF_4$). Cyclic voltammetry and linear sweep voltammetry were performed to analyze conducting behaviors. The surface characterizations were analyzed by scanning electron microscopy method and X-ray photoelectron spectroscopy. From the experimental results, increasing the $EMImBF_4$ content increased the ionic conductivity and reduced bulk resistance and interfacial resistance. In particular, after adding 15 vol% $EMImBF_4$ in 0.2 M $SBPBF_4$ PC/DMC electrolyte, the organic electrolyte showed superior capacitance and interfacial resistance. However, when $EMImBF_4$ content exceeded 15 vol%, the capacitance was saturated and the voltage range decreased.

• Journal of the korean society of oceanography
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• v.34 no.3
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• pp.144-150
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• 1999

Slope sedimentation on the modern west Florida continental margin is controlled by pelagic carbonate accumulation and off-shelf sedimentation of neritic carbonates and terrigenous fines. Production and deposition of pelagic carbonates by planktonic foraminifera and coccoliths have played a significant role in the total slope sedimentation and are mainly promoted by sea-surface productivity. Organic carbon data reflect the relatively high biological productivity in surface waters, indicating high accumulation of biogenic calcareous sediments. The surface-water productivity in the study area is supported by the relation among microfossil assemblages, carbonate mineralogy and sedimentary organic carbon.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.375-382
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• 1999

In order to investigate the contamination characteristics of the heavy metals in the mine tailings of abandoned gold mine and its surrounding agricultural soils, a sequential extraction procedure of increasing reactivity in the dissolution processes of the heavy metals(Cd, Cu, and Pb) which were associated with solid and/or solution phase in soils was attempted to partition into six particulate fractions : exchangeable, bound to carbonate, bound to Fe-Mn oxides, bound to organic matter, residual, and soluble. Among indigenous heavy metals in the mine tailings, Pb was the most abundant and Cu and Cd were followed by. Fractionation result of Pb obtained from the triplicate samples of the mine tailings were in the order of Fe-Mn oxide> Carbonate> Residual> Organic> Exchangeable> Soluble, while Wolgok series were Exchangeable > Fe-Mn oxide > Carbonate> Organic> Residual> Soluable. However the other heavy metals studied were not followed this trend. The fractionation results of mine tailing and agricultural soils demonstrated that different geochemical fractions were operationally defined by an extraction sequence that generally followed the order of decreasing solubility. Therefore potential mobility and bioavailability of heavy metals as toxic pollution sources can be evaluated when studying the pollution levels of heavy metals in soils.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.50-55
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• 2023

Lithium-ion secondary batteries are currently in high demand and supply. The purpose of this study is to secure the safety of the process by studying the combustion characteristics of EC(Ethylene Carbonate), Which is mainly used as an electrolyte organic solvent for lithium ion batteries. The flash points of the EC by using Setaflash and Pensky-Martens closed-cup testers were experimented at 141 ℃ and 143 ℃, respectively. The flash points of the EC by Tag and Cleveland open cup testers were experimented at 152 ℃ and 156 ℃, respectively. The AIT(Auto Ignition Temperature) of the EC was experimented at 420 ℃. The LEL(Lower Explosive Limit) calculated by using lower flash point of Setaflash was calculated at 3.6 Vol.%.

• Journal of the korean society of oceanography
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• v.31 no.4
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• pp.207-216
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• 1996

A geochemical study of three piston cores (ST.4, ST.6 and ST.20) taken from the Northwest Pacific (eastern edge of Shikoku Basin) provides information about changes in surface water paleoproductivity and sedimentation during the last 127 kys. Paleoproductivity variations were estimated on the basis of total organic carbon content and carbonate mass accumulation rate. The paleoproductivity based on total organic carbon shows significant spatial variations between glacial and interglacial periods. During the last glacial maximum (LGM) paleoproductivity increased about 1.5 times with deglaciation decrease compared with those of the Holocene at inner side of the Shikoku Basin (ST.4 and ST.6). On the other hand, paleoproductivity at outer side of Shikoku Basin (ST.20) indicating not distinctive increase but deglaciation increase. The C/N ratios fall below 10 for cores ST.4 and ST.6, but C/N ratios between 100 ka and 80 ka in ST.20 which show around 10 or larger values suggest a predominance of marine organic carbon with some admixture of terrigenous materials. The carbonate mass accumulation rate of three cores show different patterns of calcareous record with respect to organic carbon based paleoproductivity variation. In the inner side of Shikoku Basin (ST.4 and ST.6) the carbonate mass accumulation rate decreased during last glacial maximum, and significant increase of carbonate mass accumulation rate is recognized at outer side of Shikoku Basin (ST.20). Thus, this set of data reveals that spatial paleoproductivity variations between inner and outer side of Shikoku Basin during the glacial and interglacial periods.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.352-354
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• 2002

A series of ABA type triblock copolymers of trimethylene carbonate (TMC) and $\varepsilon$-caprolactone($\varepsilon$-CL) with different molar ratio were synthesized using ethylene glycol as initiator and stannous octoate as catalyst by ring-opening bulk polymerization. The characterization of the triblock copolymers was characterized by $^1$H-NMR, $\^$13/C-NMR, FT-IR, GPC and DSC, and compared with random copolymer. (omitted)