• Journal of Conservation Science
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• v.27 no.1
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• pp.31-40
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• 2011

Copper-red (Dongwha, Jinsa) is Korean traditional inorganic pigment used for red-coloring on the porcelain surface during Goryeo and Joseon Periods. Trace amounts of copper-red porcelains are handed down because of the technical difficulty of making and coloring of the pigment. It is known that copper ore sources were extensively distributed in Korea according to old literatures and some of them are still producing copper ore at this present. Main types of copper-bearing mineral in Korea are chalcopyrite ($CuFeS_2$) and malachite ($Cu_2CO_3(OH)_2$), and they are easily collected from the ground surface. This means Korea had geographical and economic geological advantages for supplying raw material of the pigment. These two minerals showed good red-coloring in color test for porcelain pigment. As a coloring element, copper showed micro size less than $5{\mu}m$ in diameter in glaze matrix. The dispersion of copper particle is the most decisive factor for red chromaticity of copper-red porcelain, as well as copper content of the pigment.

• Elastomers and Composites
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• v.40 no.3
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• pp.188-195
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• 2005

Chemical and physical changes and the contents of functional groups in the carbon black surface after the ozone treatment was investigated using elemental analysis, pH, tint strength, DBP, $N_2SA$, IA, and acid-base reaction. As the treatment time was increased, surface structure, particle size and surface area of carbon black did not change, while surface oxygen contents increased, and pH decreased and then saturated after $1{\sim}2$ hour. The contents of carboxylic, lactone, hydroxyl, and carbonyl groups were analyzed with four bases such as $NaHCO_3,\;Na_2CO_3,\;NaOH$, and $NaOC_2H_5$. Before oxidation, the carbonyl group was dominantly present on the surface, but by increasing the treatment time, the contents of the carboxylic and carbonyl groups increased to a saturated level after $1{\sim}2$ hour. Before and after the oxidation, the lactone and hydroxyl groups were nearly absent. These results showed that the reaction mechanism of carbon black and ozone is similar to that of ethylene and ozone. Weight of oxidized carbon black was increased after treating AIBN, while free radical was slightly decreased by ESR analysis. When carbon black was treated with organic compounds containing mercapto- groups, the results of ESR showed that free radical peak intensity was almost diminished compared to original carbon black.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.306-310
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• 2007

Characteristics of GDL (Gas Diffusion Layer) mainly determine the gas diffusion and water removal in a cell, thereby changing the performance and affecting durability of PEFC. To optimize the water management and understand the two phase flow in a GDL, it is important to study the behaviors of GDL micro structure under the real operating condition. In the clamped condition of cell, the GDL beneath the rib is more compressed than beneath the channel. Many researches on physical, electrochemical, mechanical behaviors of gas diffusion layer has been conducted. However, changes in surface properties under clamped condition have rarely studied. In present study, the morphology of broken connections of carbon fibers and detachment of PTFE coatings on the fibers were shown from the microscopic observations. In addition, changes in wetting properties of GDL by compression were investigated by using XPS and liquid uptake methods. The hydrophobic characteristics of GDL surface beneath the rib of the flow field plate are changed due to the deformation of micro structure.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.422-430
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• 2000

Three-year-old Pinus koraiensis seedlings, transplanted in brown forest soils originating from granite were treated with simulated acid rain of pH concentrations 5.6(control), 4.0, 3.0, 2.5 and 2.0 for 210 days from April 21 to November 17, 1999. Visible injury of the seedlings were observed at the pH 2.0 and pH 2.5 treatments. The total dry weight of the seedlings decreased at pH 2.0 treatment compared with that of the control, and T/R ratio increased at pH 2.0 treatment compared with others. The elements in each part of the seedlings, concentrations of Ca, P and content of chlorophyll in needles increased at the pH 2.0 treatment compared with the control. The concentration of N in the needles of the seedlings increased as the soil pH decreased. As the treated pH was lowered, soil pH has decreased, and concentrations of Ca, Mg, Al, and Mn increased, especially at pH 4.4. In addition, there was a strong correlation(r=0.90, p<0.05 ; r=-0.94, p<0.01) between the dry weight of the seedlings and the pH and Al concentration of the soils. Therefore, the pH and Al concentration in the soil may be useful indicator for assessing the effect of acid rain on the growth of woody plants.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.119-127
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• 2005

This study was carried out to investigate the effect of magnesium concentrations in fertilizer solution on growth and cut flower quality of chrysanthemum 'Biarritz'. The nutrient concentrations in plant tissue and soil solution of root media were also determined. Magnesium deficiency appeared on older leaves with interveinal yellow-green chlorosis. Marginal chlorosis and necrosis also developed on some of older leaves. Elevation of Mg concentration in fertilizer solution increased cut flower weight at harvesting stage resulting in the 8.84g in 1.5mM treatment. Dry weight of whole above ground plant tissue increased as Mg concentrations in fertilizer solution were elevated within the range from 0 to 15mM, but that of 20mM decreased compared to 15mM treatment. The dry weight of 0.5, 1.0 and 1.5mM treatments were 8.42, 8.75 and 8.848 and tissue Mg contents of those based on the youngest fully expanded leaves at harvesting stage were 0.34, 0.53 and $0.71\%$, respectively. Based on dry weight and tissue Mg contents, Mg fertilization to maintain tissue contents higher than $0.64\%$ is necessary to ensure flower quality and yield. By considering the concentration in 15mM treatment, Mg concentration in soil solution of root media should be higher than $3.68mg{\cdot}L^{-1}$ at harvesting stage.

• Journal of Ginseng Research
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• v.29 no.4
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• pp.192-205
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• 2005

This study is for geochemical relationships between ginsengs and soils from three representative soil types from Keumsan, shale, phyllite and granite areas. For this study, ginsengs (2, 3 and 4 years), with the soils and their host rock, are collected and are analysed for the transitional elements. In the weathered soils, the shale area is high in the most of elements, but low in the granite area. High correlation relationships are shown in the shale area. In the field soils, the shale area is mainly high, but low in the granite area. Comparing with ages, most of elements are high in the 2 year soils, but low in the 4 year soils. Regardless of the localities, positive and negative correlations are dominant in the shale area. In the host rocks, high element contents are shown in the phyllite and shale areas. Positive and negative correlations are found in the shale and phyllite areas for large numbers of the element pairs. In the ginsengs, differences of the element contents with ages are not clear, but show high element contents in the 2 year ginsengs of the shale and phyllite areas, and low contents in the 4 year ginsengs of the granite area. Positive correlations are shown in the Cu-Zn pair in the shale and phyllite areas, and Co-Cu pair in the granite area. In the relative ratios(weathered soil/field soil), most of elements from the shale area are high, above I, suggesting high element contents in the weathered soils of the shale area relative to the granite and phyllite areas. In the relative ratios(weathered soil/host rock), most of elements are above 1, suggesting the high element contents in the weathered soils relative to the host rocks. Relative ratios (soil/ginseng) of the element contents are several to ten times. Regardless of the areas, big differences of the relative ratios are found in the Co and small differences are in the Cu and Zn, which suggest that differences between soils and ginsengs are big in the Co contents and small in the Cu and Zn contents. Regardless of the ages, differences among relative ratios are small in granite area relative to the shale area, which suggest more similar contents between ginsengs and soils in the granite areas.

• Journal of the Mineralogical Society of Korea
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• v.30 no.1
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• pp.11-19
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• 2017

Reddish brown clay-silt sediments covered granitoid weathering crust in the Jangdongri area, Naju, Korea. Mineralogical and geochemical properties of the ~2 m sediment section were investigated. The sediments were composed mainly of quartz (50%) and clay minerals (45%) with minor contents of K-feldspar, goethite, hematite, and gibbsite. The clay minerals were illite, illite-smectite mixed-layers, vermiculite, hydroxy-Al vermiculite, kaolinite, and halloysite. Mineral composition varied little through the section with the minor upward enrichment of plagioclase and chlorite. Abundant illitic clay minerals indicated the remote source of the sediments because clays derived by granite weathering in Korea were dominated by kaolin minerals. A comparison with the mineral composition of Asian dust (Hwangsa) suggested that plagioclase and K-feldspar disappeared by chemical weathering after deposition, resulting in the quartz and clay-rich sediments. Plagioclase and chlorite altered to kaolin and vermiculite, respectively. Goethite and hematite derived by the weathering of iron-bearing minerals stained the sediment to reddish brown color. The mineralogical and geochemical properties of the reddish brown clay-silt sediments were consistent with those of eolian deposits identified in Korea, supporting eolian origin of the Jangdongri sediments, requiring future confirmation including age dating and isotopic analysis.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.234-238
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• 2016

Solid ash-free coal (AFC) samples recovered from solvent-extracted solution by vacuum drying, dilution precipitation and spray drying methods were compared in terms of physical properties and chemical structure. AFC was prepared by using Kideco coal (Indonesian sub-bituminous coal) and polar N-methyl-2-pyrrolidone (NMP) solvent as raw materials. The physical properties of the AFCs were characterized with proximate, ultimate, and calorific value analysis. In analyzing the chemical structure, FTIR and NMR were used. the proximate analysis showed much reduced ash in the AFCs compared to parent raw coal. The FTIR result showed that the extraction solvent was not fully removed from the AFC prepared by vacuum drying. However, the solvent was not detected in the AFC recovered by using dilution precipitation. Dilution precipitation has advantages over the other two methods, since it can be done at relatively low temperature and separate ash-free coal from extraction solvent more effectively.

• Journal of the Korean Electrochemical Society
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• v.8 no.2
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• pp.94-98
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• 2005

Coptp films with the additive elements (X=Fe, Mn) of varying concentrations were prepared by in-situ electrodeposition, to tailor their magnetic properties. Alloys of CoPtP-X (X=Fe, Mn) were synthesized by changing the solution concentrations of Fe and Mn for electrodeposition. In the electrodeposited CoFePtP alloys, preferred orientation of the electrodeposited films changed from hexagonal (001) to (100) direction with increasing iron contents as revealed by X-ray diffraction, and these films exhibited various magnetic properties ranging from a typical hard magnetic to a soft magnetic property in accordance with microstructural variations. In the case of Mn addition, excellent hard magnetic property was observed at a specific Mn concentration of 0.0126 M in the electrolyte, with the coercivity of 4630 Oe and squareness of 0.856 and this was attributed to the fact that magnetization easy-axis (hexagonal c-axis) coincides with the preferred growth orientation of the film confirmed by transmission electron microscopy.

• Polymer(Korea)
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• v.29 no.5
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• pp.501-507
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• 2005

Small intestinal submucosa (SIS) had been widely used as a biomaterial without immune rejection responses. SIS sponges prepared by crosslinking with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). SIS powders dissolved in $3\%(v/v)$ acetic acid aqueous solution for 48hrs and freeze-dried. EDC solution ($H_2O$ : ethanol = 5 : 95) as a crosslink agent was used in concentration of 100mM. In vitro, rat-BMSCs seeded in SIS sponges and induced the osteogenesis for 28 days. We have characterized the osteogenic potential of rat-BMSCs in SIS sponges by alkaline phosphatase activity(ALP), n assay, SEM and RT-PCR for osteogenic phenotype. In SEM, all morphology of SIS sponges was regular and showed interconnected pore structure. By RT-PCR analysis, we observed type I collagen expression. These results demonstrate osteogenic differentiation of rat-BMSCs. In conclusion, we confirmed that the morphology of surface, cross-section, and side of SIS sponges were highly porous with good interconnections between each pores, which can support the surface of cell growth, proliferation, and differentiation. This result indicates that SIS sponge is useful for osteogenesis of BMSCs.