• The Journal of the Petrological Society of Korea
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• v.3 no.2
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• pp.138-155
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• 1994

Granitic gneiss containing biotite banded gneiss relict around the Daeheung talc deposit are widely distributed which were formed by regional metamorphism of both epidote-amphibolite and iater greenschist facies and granitization. They were derived from same silico-aluminous rocks of sedimentary origin. The mineral assemblages, which are common in the biotite banded gneiss, formed during regional metamorphisms, are survived in the granitic gneiss. The mineral assemblages of the latter greenschist facies may be formed retrogressively from the first epidote-amphibolite facies. The chemical compositions of biotite, muscovite, and chlorite, the important constituents of the gneisses, were controlled by the bulk composition, the chemical composition of the original mineral, and environment of the regional metamorphisms and granitization. The chemical equilibrium between coexisting'minerals, especially biotite and muscovite, is relatively well established, which was controlled mainly by tschermakitic and phengitic substitutions. Cholrite was formed mainly from either biotite or muscovite by retrogressive alteration or granitization, and have nearly similar chemical compositions regardless of the occurrences. The orientation trend of the foliation, joint and quartz vein developed in the gneisses was analyzed by equal area projection which the latter two show nearly identical trend in the strike and dip. This may suggest that the hydrothermal solution was introduced along joint during wet granitization.

• The Journal of the Petrological Society of Korea
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• v.4 no.1
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• pp.49-58
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• 1995

Staurolite-biotite-andalusite-garnet (SBAG) assemblage and its sub-assemblages (SBA and SBG) commonly occur in the Dueumri Formation near the Chunyang granite, belonging to andalusite and sillimanite zones. The occurrence of the SBAG mineral assemblage is unusual because it is univariant in the $K_2O-FeO-MgO-Al_2O_3-SiO_2-H_2O$ (KFMASH) model system. We used projection and singular value decomposition (SVD) methods to investigate the equilibrium relationship between SBAG and its sub-assemblage. The SVD modelling of single specimen containing the SBAG assemblage suggests no reaction relationship with respect to mass-balance. Thus, the SBAG assemblages are stabilized by non-KFMASH component. On the other hand, the AFM-Mn projection suggests a reaction relationship between SBAG and its sub-assemblage because they intersect each other in this composition space. The SVD modelling, however, suggests no reaction relationship between these assemblages. Thus, the SBAG assemblages are likely to be stabilized by the variation in bulk-rock composition and/or 1.1~2,. The stable occurrence of staurolite in the sillimanite zone is compatible with pressure estimates from the garnet-plagioclase-biotite-muscovite geobarometer.

• Economic and Environmental Geology
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• v.35 no.2
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• pp.121-136
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• 2002

The $CO_2$-rich springs in the Kyungpook Province has been found at 16 locations. Most of the $CO_2$-rich springs outflow along either fault zones or the geologic boundary between Mesozoic granites and their adjacent rocks. The $CO_2$-rich water samples show a high $CO_2$ concentration ( $P_{CO2}0.46 to 5.21 atm), weak acidic pHs, wide electrical conductivity values ranging from 422 to 2,280 $\mu\textrm{S}$/cm, and high re content. They are classified into the ca-HC $O_3$ type in chemical composition.$\delta$$^{18}$ O and $\delta$$^2$H data indicate that $CO_2$-rich water is meteoric origin. The $\delta$$^{13}$ C values (-1.5$\textperthousand$ to -6.1$\textperthousand$ PDB) suggest that dissolved $H_2$C $O_3$$^{0}$ C $O_3$- are mainly derived from a deep-seated $CO_2$ and carbonate minerals. The thermodynamic equilibrium state between $CO_2$-rich water and major minerals, and hydrochemical characteristics indicate that major source minerals determining the chemical composition of $CO_2$-rich water are carbonate minerals, plagioclase, K-feldspar and Fe-oxides. Under high $CO_2$ pressure and the weak acidic condition, most of the $CO_2$-rich water samples are thermodynamically in the dissolution state with respect to albite and carbonate minerals.

• The Journal of Engineering Geology
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• v.9 no.3
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• pp.207-225
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• 1999

Twenty water samples (eleven groundwater and nine geothermal water samples) were collected to elucidate hydrogeochemical characteristics of the groundwater and geothermal water in the Dongrae hot-spring area and its vicinity. Major and minor elements were analyzed for ground and geothermal water samples. Physicochemical properties of the groundwater and the geothermal water were examined and chemical composition of the two waters were compared. Factor and correlation analyses were carried out to simplify the physicochemical data into grouping some factors and to find interaction between them. The groundwaters belong to $Ca-HCO_3$ type, while the geothermal waters belong to Na-Cl type. The Na and Cl concentrations in the Dongrae hot-spring area are higher than those of other granite areas in South Korea. The Na/Cl weight ratio ranges from 0.7 to 1.3 for the geothermal waters. On the phase stability diagram groundwaters fall effectively in the field of stability of kaolinite, while geothermal waters fall in the stability field of microcline or kolinite depending on the chemical composition system. Based on the Na-K, Na-K-Ca and Na-K-Ca-Mg geothermometers, the geothermal reservoir is estimated to have equilibrium temperature between 115 and $145^{\circ}C$.

• Clean Technology
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• v.13 no.1 s.36
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• pp.34-45
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• 2007

Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dichloromethane and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing dichloromethane as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of dichloromethane and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the dichloromethane composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature. The second half of this work is focused on the particle formation of the simvastatin drug by a supercritical anti-solvent recrystallization process in a cylindrical high-pressure vessel equipped with an impeller. Microparticles of the simvastatin drug were prepared as functions of pressure (8 MPa to 12 MPa), temperature (303.15 K, 313,15 K), feed flow rate of carbon dioxide, and stirring speed (up to 3000 rpm), in order to observe the effect of those process parameters on the size and shape of the drug microparticles recrystallized.

• 한국해양학회지
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• v.29 no.2
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• pp.164-170
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• 1994

The well preserved ostracodes of the Chunbuk Formation in Pohang Basin were analyzed isotopically to understand paleoceanographic conditions of the southeastern park of Korean peninsula which Songhacdong, and Mulcheonri areas range from - 2.2 to - 0.7% (PDB), - 0.7 to 0.0% , and -20.0 to - 0.8%, and their corresponding paleotemperatures range from ca 20 to 27$^{\circ}C$ (average = 24$^{\circ}C$), 17 to 20$^{\circ}C$ (average = 18$^{\circ}C$), and 20 to 26$^{\circ}C$ (average=23$^{\circ}C$),respectively. Assuming the $\delta$/SUP 18/O composition of the Middle Miocene seawater was about - 0.34% (SMOW), the paleotemperatures of the Middle Miocene shallow seawater in the Pohang Basin was almost equal to or slightly higher than the present summer temperature (ca 16 to 20$^{\circ}C$) near Pohang area. Carbon isotopic value of Cyhere omotenipponica is - 0.8% (PDB), reflecting marine carbonate carbon composition. Carbon isotopic compositions of other ostracodes such as Aurial okumurai, Trachyleberis niitsmai, Urocythereis sp., Urocythereis cf. gorokuensis, and Acanthocythereis mutsuensis range from - 5.2 to - 3.4% (PDB), which might have secreted their shells out of equilibrium with ambient seawater. This disequilibrium was most likely to have resulted from metabolic (=vital) effect, rather than temperature of productivity.

• The Journal of the Petrological Society of Korea
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• v.25 no.3
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• pp.261-281
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• 2016

Our knowledge of the lithosphere beneath the Korean Peninsula has been improved through petrologic and geochemical studies of upper mantle xenoliths hosted by Quaternary intraplate alkali basalts from Jeju Island. The xenoliths are mostly spinel lherzolites, accompanied by subordinate harzburgite and pyroxenites. The mantle xenoliths represent residual mantle material showing textural and geochemical evidence for at least a three-stage evolution, fractional partial melting, recrystallization, and metasomatism. Their composition primarily controlled by early fractional melt extraction and porphyroclastic and mylonitic fabrics formed in a shear-dominated environment, which was subsequently modified by residual slab-derived fluids (or melts). Modal metasomatic products occur as both anhydrous phase(orthopyroxene) and hydrous phase (phlogopite). Late-stage orthopyroxene is more common than phlogopite. However, chemical equilibrium is evident between the primary and secondary orthopyroxene, implying that the duration of post-metasomatic high temperatures enabled complete resetting/reequilibration of the mineral compositions. The metasomatic enrichment pre-dates the host Jeju Quaternary magmatism, and a genetic relationship with the host magmas is considered unlikely. Following enrichment in the peridotite protolith in the mantle wedge, the upper mantle beneath proto-Jeju Island was transformed from a subarc environment to an intraplate environment. The Jeju peridotites, representing old subarc fragments, were subsequently transported to the surface, incorporated into ascending Quaternary intraplate alkali basalt. The result of this study implies that long term material transfer in the transformation of geotectonic setting from a subarc to intraplate may have played a significant role in the evolution of lithospheric mantle, resulting in the enriched mantle domains, such as EM I or EM II in the lithospheric mantle beneath East Asia.

• Animal Bioscience
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• v.37 no.2
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• pp.274-283
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• 2024

Objective: The aim of the study was to evaluate the physicochemical properties (nutrient composition, pH, water content and activity, sorption properties) and mechanical properties (compression force and energy) of granulated feed mixtures with various inclusion levels of crude fibre concentrates ARBOCEL and VITACEL for broiler chickens, i.e. +0.0% (control group - group C), +0.3%, +0.8%, +1.0%, +1.2%. Methods: The feed mixtures were analyzed for their physicochemical properties (nutrient composition by near-infrared spectroscopy, pH with the use a CP-401 pH meter with an IJ-44C glass electrode, water content was determined with the drying method and activity was determined with the Aqua Lab Series 3, sorption properties was determined with the static method) and mechanical properties (compression force and energy with the use TA-HD plus texture analyzer). The Guggenheim-Anderson-de Boer (GAB) model applied in the study correctly described the sorption properties of the analyzed feed mixtures in terms of water activity. Results: The fibre concentrate type affected the specific surface area of the adsorbent and equilibrium water content in the GAB monolayer (p≤0.05) (significantly statistical). The type and dose of the fibre concentrate influenced the dimensionless C and k parameters of the GAB model related to the properties of the monolayer and multilayers, respectively (p≤0.05). They also affected the pH value of the analyzed feed mixtures (p≤0.05). In addition, crude fibre type influenced water activity (p≤0.05) as well as compression energy (J) and compression force (N) (p≤0.001) (highly significantly statistical) of the feed mixtures. Conclusion: The physicochemical analyses of feed mixtures with various inclusion levels (0.3%, 0.8%, 1.0%, 1.2%) of crude fiber concentrates ARBOCEL or VITACEL demonstrated that both crude fiber types may be used in the feed industry as a feedstuff material to produce starter type mixtures for broiler chickens.

• Korean Journal of Materials Research
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• v.11 no.12
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• pp.1035-1041
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• 2001

The refining process and solubility of Ti in Al matrix during mechanical alloying (MA) were investigated by using X-ray diffraction (XRD), transmission electron microscopy (TEM) as functions of alloy composition, milling time and ball to powder ratio (BPR). Mechanical alloyed samples were annealed for investigating their stability and the formation behavior of$Al_3Ti$in the temperature range from$200{\circ}C$to$600{\circ}C$. It is observed from present experimental that disappearance of Ti peaks in mechanically alloyed Al-10wt%Ti is not simply attributable to the dissolution of Ti into Al, but associated mainly with extreme refining and/or heavy straining of Ti particles The annealing of the mechanically alloyed Al-Ti powders show differences in aluminide formation behavior when Ti content in Al is equal to or less than l0wt% and higher than l5wt%Ti. When Ti-content in Al is equal to or less than l0wt%, the MA powders transform directly to a global equilibrium state forming $DO_{22}- type\;Al_3$Ti above$400{\circ}C$. In the Al-Ti samples with equal to or higher than l5wt%Ti, transitional phases of cubic$Al_3Ti$and tetragonal $Al_{24}Ti_8$ are formed above$400{\circ}C$. They are stable only below$500{\circ}C$, and, $DO_{22}-type\;Al_3Ti$ becomes dominant aluminide at temperature higher than$ 600{\circ}C$.

• Economic and Environmental Geology
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• v.14 no.4
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• pp.167-182
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• 1981

Skarn silicates from the Shinyemi lead-zinc ore deposits can be distinguished as following three mineral assemblages: 1) garnet-pyroxene-phlogopite-wollastonite assemblages, 2) garnet-pyroxene assemblages, 3) garnet-epidote assemblages The assemblages are considered to be related with occurrences and kindes of ore minerals, and stage of mineralization in the deposits. Microprobe analyses of some garnets from the deposits show strong chemical zoning which is due to the changing equilibrium condition during growth of garnet crystal. Depositional condition of ore deposits and place of the ore-related igneous rock are discussed in the light of chemical composition of garnet and occurence of skarns in the Shinyemi.