• Proceedings of the Mineralogical Society of Korea Conference
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• 2003.05a
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• pp.66-66
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• 2003

King George island, Antarctica, is mostly covered by ice sheet and glaciers, but the land area is focally exposed for several thousand years after deglaciation. For a mineralogical study of chemical weathering in the polar environment, glacial debris was sampled at the well-developed patterned ground which was formed by long periglaclal process. As fresh equivalents, recently exposed tills were sampled at the base of ice cliff of outlet glaciers and at the melting margin of ice cap together with fresh bedrock samples. Fresh tills are mostly composed of quartz, plagioclase, chlorite, and illite, but those derived from hydrothermal alteration zone contain smectite and illite-smectite. In bedrocks, chlorite was the major clay minerals in most samples with minor illite near hydrothermal alteration zone and interstratified chlorite-smectite in some samples. Smectite closely associated with eolian volcanic glass was assigned to alteration in their source region. Blocks with rough surface due to chemical disintegration showed weathering rinds of several millimeter thick. Comparision between inner fresh and outer altered zones did not show notable change in clay mineralogy except dissolution of calcite and some plagioclase. Most significant weathering was observed in the biotite flakes, eolian volcanic glass, sulfides, and carbonates in the debris. Biotite flakes derived from granodiorite were altered to hydrobiotite and vermiculite of yellow brown color. Minor epitactic kaolinite and gibbsite were formed in the cleaved flakes of weathered biotite. Pyrite was replaced by iron oxides. Calcite was congruently dissolved. Volcanic glass of basaltic andesite composition showed alteration rim of several micrometer thick or completely dissolved leaving mesh of plagioclase laths. In the alteration rim, Si, Na, Mg, and Ca were depleted, whereas Al, Ti, and Fe were relatively enriched. Mineralization of lichen and moss debris is of much interest. They are rich of A3 and Si roughly in the ratio of 2:1 to 3:1 typical of allophane. In some case, Fe and Ti are enriched in addition to Al and Si. Transmission electron microscopy of the samples rich of volcanic glass showed abundant amorphous aluminosilicates, which are interpreted as allophane. Chemical weathering in the King George Island is dominated by the leaching of primary phyllosilicates, carbonates, eolian volcanic glass, and minor sulfides. Authigenesls of clay minerals is less active. Absence of a positive evidence of significant authigenic smectite formation suggests that its contribution to the clay mineralogy of marine sediments are doubtful even near the maritime Antarctica undergoing a more rapid and intenser chemical weathering under more humid and milder climate.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.1-11
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• 2007

The objectives of this study are: (1) to compare the rates and pathways of organic matter minerlaization at stagnant freshwater wetland in Shiwha to highly irrigated coastal wetland in Ganghwa; and (2) to discuss the significance of irrigation into the sediment in controlling the organic carbon oxidation in Shiwha wetland. Concentrations of $CO_2$, $NH_4{^+}$ and $H_2S$ in the pore water of the Shiwha wetland were 3 times, 30 times, and 3 times higher than that in the pore water of the Ganghwa wetland, respectively. The ratio of Fe(III) to total reduced sulfur at the Ganghwa wetland was 12 times higher than at the Shiwha wetland. The results indicated that the Ganghwa wetland with frequent tidal inundation were relatively oxidized than highly stagnant Shiwha wetland. Rates of organic matter oxidation at the Ganghwa wetland ($0.039mM\;C\;h{-1}$) was 390 times higher than that at the Shiwha wetland ($0.0001mM\;C\;h{-1}$). Rates of sulfate reduction at the Shiwha wetland ($314{\sim}580nmol\;cm^{-3}\;d{-1}$) were comparable to the sulfate reduction at Ganghwa wetland ($2{\sim}769nmol\;cm^{-3}\; d{-1}$), whereas Fe(III) reduction rates were 1.7 times higher at the Ganghwa wetland ($0.1368{\mu}mol\;cm^{-3}\;d{-1}$) than at the Shiwha wetland ($0.087{\mu}mol\;cm^{-3}\;d{-1}$). The results implied that the water flow system of the Shiwha wetland was too stagnant to flush out the reduced pore water from the sediment, and thus anaerobic microbial respiration was limited by the availability of electron acceptors.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.307-327
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• 2008

Geochemical study on the rocks and minerals of the Gyeongju low and intermediate level waste repository was carried out in order to provide geochemical data for the safety assessment and geochemical modeling. Polarized microscopy, X-ray diffraction method, chemical analysis for the major and trace elements, scanning electron microscopy(SEM), and stable isotope analysis were applied. Fracture zones are locally developed with various degrees of alteration in the study area. The study area is mainly composed of granodiorite and diorite and their relation is gradational in the field. However, they could be easily distinguished by their chemical property. The granodiorite showed higher $SiO_2$ content and lower MgO and $Fe_2O_3$ contents than the diorite. Variation trends of the major elements of the granodiorite and diorite were plotted on the same line according to the increase of $SiO_2$ content suggesting that they were differentiated from the same magma. Spatial distribution of the various elements showed that the diorite region had lower $SiO_2,\;Al_2O_3,\;Na_2O\;and\;K_2O$ contents, and higher CaO, $Fe_2O_3$ contents than the granodiorite region. Especially, because the differences in the CaO and $Na_2O$ distribution were most distinct and their trends were reciprocal, the chemical variation of the plagioclase of the granitic rocks was the main parameter of the chemical variation of the host rocks in the study area. Identified fracture-filling minerals from the drill core were montmorillonite, zeolite minerals, chlorite, illite, calcite and pyrite. Especially pyrite and laumontite, which are known as indicating minerals of hydrothermal alteration, were widely distributed in the study area indicating that the study area was affected by mineralization and/or hydrothermal alteration. Sulfur isotope analysis for the pyrite and oxygen-hydrogen stable isotope analysis for the clay minerals indicated that they were originated from the magma. Therefore, it is considered that the fracture-filling minerals from the study area were affected by the hydrothermal solution as well as the simply water-rock interaction.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.563-572
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• 2006

In order to propose optimum in-situ treatment for reducing phosphorous release from sediment of stationary lakes, a series of column tests were performed. The sediment used in experiment was very fine clay with a mean grain site $7.7{\phi}$ and high $C_{org}$ contents(2.4%). Phosphorous releases were evaluated in two ways : in lake water(with microbial effect) and in distilled water(without microbial effect). As in-situ capping material, sand and loess were used while Fe-Gypsum and $SiO_2$-Gypsum were used for in-situ chemical treatment. In case of lake water considering the effect of microorganism, phosphorous concentration rapidly decreased in the early stage of experiment but it was gradually increased after 10 days. Flux of phosphorous release for control was $3.0mg/m^2{\cdot}d$. Whereas, those for sand layer capping(5 cm) and loess layer capping(5 cm) were $2.5mg/m^2{\cdot}d\;and\;1.8mg/m^2{\cdot}d$, respectively because the latter two were not consolidated sufficiently. For Fe-gypsum and $SiO_2$-gypsum the fluxes were $1.4mg/m^2{\cdot}d$ which meant that reduction efficiency of phosphorous release was more than 40% higher than that of control. The case capping with complex layer was $1.0mg/m^2{\cdot}d$, which showed high reduction efficiency over 60%. The addition of gypsum($CaSO_4{\cdot}2H_2O$) into the sediment reduced release of Phosphorus from the sediments. Gypsum acted as a slow-releasing source of sulphate in sediment, which enhanced the activity of SRB(sulfate reducing bacteria) and improved the overall mineralization rate of organic matter.

• Economic and Environmental Geology
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• v.27 no.6
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• pp.523-535
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• 1994

The strata-bound type iron ore bodies in the Chungju mine are interbedded with metamorphic rocks which are intruded by Mesozoic granitic rocks. The iron ore deposit occurs as layer or lens shape which are concordant with the metamorphic rocks. The iron ore is classified into banded and massive types based on the mode of texture and occurrence. Grain size and iron-oxides tend to become coarser toward massive ore than banded ore. Banded ores commonly contain internal layers defined by alternating magnetite- rich, hematite-rich, magnetite-hematite, and quartz-rich mesobands. The banded iron ore consists of hematite, magnetite, quartz, feldspar, and minor amounts of biotite, muscovite, chlorite, carbonates, epidote, allanite, and zircon. Massive ores which are characterized by high magnetite content occur in contact of granitic rocks. The massive iron ores consist mostly of magnetite and quartz, with minor amounts of hematite, pyrite, microcline, biotite, muscovite, chlorite, carbonates, epidote, allanite and zircon. Magnetite from banded and massive ores is almost pure $Fe_3O_4$ in composition, including 0.14 to 0.27 wt.% MnO and 0.10 to 0.15 wt.% MnO, respectively. Hematite of the ore contains 0.87 to 1.27 wt.% $TiO_2$ in banded ore and 3.44 to 6.96 wt.% $TiO_2$ in massive ore, respectively. Biotite shows a little compositional variation depending on ore types. Biotite of the banded ore has lower FeO, $TiO_2$ and $Al_2O_3$, and higher MgO and $SiO_2$ than the massive ore. The modes of occurrence and petrography of ore implies that massive ores might have been formed either under more reducing environments or higher temperature condition than banded ore. Banded ores might represent early episode of iron enrichment due to regional metamorphism. Massive ores might be related to the contact metamorphism resulting from late granitic intrusion.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.179-189
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• 2002

The Geology of the Shizhuyuan W-Sn-Bi-Mo deposits, situated 16 Ian southeast of Chengzhou City, Hunan Province, China, consist of Proterozoic metasedimentary rocks, Devonian carbonate rocks, Jurassic granitic rocks, Cretaceous granite porphyry and ultramafic dykes. The Shizhuyuan polymetallic deposits were associated with medium- to coarse-grained biotite granite of stage I. According to occurrences of ore body, ore minerals and assemblages, they might be classified into three stages such as skarn, greisen and hydrothernlal stages. The skarn is mainly calcic skarn, which develops around the Qianlishan granite, and consists of garnet, pyroxene, vesuvianite, wollastonite, amphibolite, fluorite, epidote, calcite, scheelite, wolframite, bismuthinite, molybdenite, cassiterite, native bismuth, unidetified Bi- Te-S system mineral, magnetite, and hematite. The greisen was related to residual fluid of medium- to coarse-grained biotite granite, and is classified into planar and vein types. It is composed of quartz, feldspar, muscovite, chlorite, tourmaline, topaz, apatite, beryl, scheelite, wolframite, bismuthinite, molybdenite, cassiterite, native bismuth, unknown uranium mineral, unknown REE mineral, pyrite, magnetite, and chalcopyrite with minor hematite. The hydrothermal stage was related to Cretaceous porphyry, and consist of quartz, pyrite and chalcopyrite. Scheelite shows a zonal texture, and higher MoO) content as 9.17% in central part. Wolframite is WO); 71.20 to 77.37 wt.%, FeO; 9.37 to 18.40 wt.%, MnO; 8.17 to 15.31 wt.% and CaO; 0.01 to 4.82 wt.%. FeO contents of cassiterite are 0.49 to 4.75 wt.%, and show higher contents (4.]7 to 4.75 wt.%) in skarn stage (Stage I). Te and Se contents of native bismuth range from 0.00 to 1.06 wt.% and from 0.00 to 0.57 wt.%, respectively. Unidentified Bi-Te-S system mineral is Bi; 78.62 to 80.75 wt.%, Te; 12.26 to 14.76 wt.%, Cu; 0.00 to 0.42 wt.%, S; 5.68 to 6.84 wt.%, Se; 0.44 to 0.78 wt.%.

• Economic and Environmental Geology
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• v.30 no.4
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• pp.289-301
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• 1997

The Boguk cobalt mine is located within the Cretaceous Gyeongsang Sedimentary Basin. Major ore minerals including cobalt-bearing minerals (loellingite, cobaltite, and glaucodot) and Co-bearing arsenopyrite occur together with base-metal sulfides (pyrrhotite, chalcopyrite, pyrite, sphalerite, etc.) and minor amounts of oxides (magnetite and hematite) within fracture-filling $quartz{\pm}actinolite{\pm}carbonate$ veins. These veins are developed within an epicrustal micrographic granite stock which intrudes the Konchonri Formation (mainly of shale). Radiometric date of the granite (85.98 Ma) indicates a Late Cretaceous age for granite emplacement and associated cobalt mineralization. The vein mineralogy is relatively complex and changes with time: cobalt-bearing minerals with actinolite, carbonates, and quartz gangues (stages I and II) ${\rightarrow}$ base-metal sulfides, gold, and Fe oxides with quartz gangues (stage III) ${\rightarrow}$ barren carbonates (stages IV and V). The common occurrence of high-temperature minerals (cobalt-bearing minerals, molybdenite and actinolite) with low-temperature minerals (base-metal sulfides, gold and carbonates) in veins indicates a xenothermal condition of the hydrothermal mineralization. High enrichment of Co in the granite (avg. 50.90 ppm) indicates the magmatic hydrothermal derivation of cobalt from this cooling granite stock, whereas higher amounts of Cu and Zn in the Konchonri Formation shale suggest their derivations largely from shale. The decrease in temperature of hydrothermal fluids with a concomitant increase in fugacity of oxygen with time (for cobalt deposition in stages I and II, $T=560^{\circ}C-390^{\circ}C$ and log $fO_2=$ >-32.7 to -30.7 atm at $350^{\circ}C$; for base-metal sulfide deposition in stage III, $T=380^{\circ}-345^{\circ}C$ and log $fO_2={\geq}-30.7$ atm at $350^{\circ}C$) indicates a transition of the hydrothermal system from a magmatic-water domination toward a less-evolved meteoric-water domination. Sulfur isotope data of stage II sulfide minerals evidence that early, Co-bearing hydrothermal fluids derived originally from an igneous source with a ${\delta}^{34}S_{{\Sigma}S}$ value near 3 to 5‰. The remarkable increase in ${\delta}^{34}S_{H2S}$ values of hydrothermal fluids with time from cobalt deposition in stage II (3-5‰) to base-metal sulfide deposition in stage III (up to about 20‰) also indicates the change of the hydrothermal system toward the meteoric water domination, which resulted in the leaching-out and concentration of isotopically heavier sulfur (sedimentary sulfates), base metals (Cu, Zn, etc.) and gold from surrounding sedimentary rocks during the huge, meteoric water circulation. We suggest that without the formation of the later, meteoric water circulation extensively through surrounding sedimentary rocks the Boguk cobalt deposits would be simple veins only with actinolite + quartz + cobalt-bearing minerals. Furthermore, the formation of the meteoric water circulation after the culmination of a magmatic hydrothermal system resulted in the common occurrence of high-temperature minerals with later, lower-temperature minerals, resulting in a xenothermal feature of the mineralization.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.3
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• pp.245-253
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• 2011

Purpose: The aim of this in vitro study was to estimate surface characteristic after peptide coating and investigate biological response of human mesenchymal stem cell to anodized titanium discs coated with RGD peptide by physical adhesion and chemical fixation. Materials and methods: Fluorescence isothiocyanate (FITC) modified RGD-peptide was coated on the anodized titanium discs (diameter 12 mm, height 3 mm) using two methods. One was physical adhesion method and the other was chemical fixation method. Physical adhesion was performed by dip and dry procedure, chemical fixation was performed by covalent bond via silanization. In this study, human mesenchymal stem cell was used for experiments. The experiments consisted of surface characteristic evaluation after peptide coating, analysis about cell adhesion, proliferation, differentiation, and mineralization. Obtained data are statistically treated using Kruskal-Wallis test and Bonferroni test was performed as post hoc test (P=.05). Results: The evaluation of FE-SEM images revealed no diffenrence at micro-surfaces between each groups. Total coating dose was higher at physical adhesion experimental group than at chemical fixation experimental group. In cell adhesion and proliferation, RGD peptide coating did not show a statistical significance compared with control group (P>.05). In cell differentiation and mineralization, physical adhesion method displayed significantly increased levels compared with control group and chemical fixation method (P<.05). Conclusion: RGD peptide coating seems to enhance osseointegration by effects on the response of human mesenchymal stem cell. Especially physical adhesion method showed more effective than chemical fixation method on response of human mesenchymal stem cell.

• Economic and Environmental Geology
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• v.45 no.1
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• pp.1-8
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• 2012

Copper-zinc-bearing skarns of the Kasihan area developed at limestone layers in the sedimentary facies of the Late Oligocene Arjosari Formation. The skarns consist mainly of fine-grained, massive clinopyroxene-garnet, garnet, garnet-epidote, and epidote skarns. Most copper and zinc(-lead) ore mineralization occur in the clinopyroxene-garnet and garnetepidote skarn, respectively. Clinopyroxene occurs as a continuous solid solution of diopside and hedenbergite (from nearly pure diopside up to ${\approx}34$ mole percent hedenbergite), with a maximum 28.2 mole percent johannsenite component. The early and late pyroxenes of Kasihan skarns are diopsidic and salitic, respectively. They fall in the fields typical Cu- and Zn-dominated skarns, respectively. Garnet displays a relatively wide range of solid solution between grossular and andradite with up to ${\approx}2.0$ weight percent MnO. Garnet in early pyroxene-garnet skarn ranges from 49.1 to 91.5 mole percent grossular (mainly ${\geq}78$ mole % grossular). Garnets in late garnet and garnet-epidote skarns range from 2.8 to 91.4 mole percent grossular (mainly ${\geq}70$ mole % for garnet skarn). Epidote compositions indicate solid solutions of clinozoisite and pistacite varying from 65.8 to 76.2 mole percent clinozoisite. Phase equilibria indicate that skarn evolution was the result of interaction of water-rich fluids ($X_{CO_2}{\leq}0.1$) with original lithologies at ${\approx}0.5$ kb with declining temperature (early clinopyroxene-garnet and garnet skarn, ${\approx}450$ to $370^{\circ}C$; late garnet-epidote and epidote skarn, ${\approx}370$ to $300^{\circ}C$).

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.213-220
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• 2013

Two types of onions cultivated with different methods of sulfur application (designated as S-1 and S-2) were examined for their physicochemical and sensory properties, and then compared with onions without sulfur application as a control. During cultivation, dietary sulfur methylsulfonylmethane (MSM) was sprayed on the leaves twice starting at 2 months before harvest, with one month intervals for S-1. For S-2, the MSM was applied once onto surface soils before sowing, and then once again on the leaves at 2 months before harvest. Thiosulfinate, a major sulfur-containing compound in onions, increased in the order of control, S-1, and S-2, without noticeable differences in the strength of spicy hot taste and flavor. The S-2 onions demonstrated a total reducing capacity three times higher than control and S-1 did. It indicates that the application of sulfur would positively affect the quality of onions under the condition where sufficient time is given for soil mineralization.