• Journal of Applied Reliability
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• v.15 no.3
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• pp.197-206
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• 2015

Failure analysis of pre-insulated pipe (SPPS 380, 400A) transporting high temperature water ($95{\sim}110^{\circ}C$) for a plant was carried out. The damaged area (${\Phi}5mm$) of pre-insulated pipe was found only on welds. The chemical composition of damaged pipe meets specification of carbon steel pipes for pressure service (KS D 3562). As results of microstructure analysis, crack propagated from outer to inside after pitting corrosion occurred on the outside surface. The non-metallic inclusion existed on the end of crack. And the non-metallic inclusion continuously and linearly formed along with the bond line of welds. Based on SEM-EDS analysis, the nonmetallic inclusions have higher Manganese (Mn) and Oxygen (O) content but sulfur (S) was not detected. As results of water quality analysis, hydrogen ion concentration and minerals like Fe, Mg, Si were in low level. But the content of dissolved oxygen (11.2 ppm) was slightly higher than that of standard. It seems that the cause of damaged pipe is grooving corrosion due to MnO inclusion formed on bond line and corrosion took place nearby welds.

• Economic and Environmental Geology
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• v.23 no.1
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• pp.1-9
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• 1990

A couple of Au-Ag-bearing epithermal quartz veins of Cretaceous(87.9Ma) in age are developed in the Cretaceous(112Ma) granodiorite batholith which was emplaced in Mesozoic Baegyari sedimentary formation. Au minerals consist mostly of electrum with a 54.2-61.9 wt% Au and are closely associated with sulfide minerals including pyrite, chalcopyrite, pyrrhotite, galena and sphalerite. Homogenization temperatures of fluid inclusions in quartz, fluorite and calcite are $196-368^{\circ}C$ (avg. $240^{\circ}C$), $74-176^{\circ}C$ (avg. $115^{\circ}C$) and $75-200^{\circ}C$ (avg. $119^{\circ}C$) respectively. Sulfur isotopic compositions( +5- +8‰) of ore sulfides indicate a deep-seated sulfur origin. Oxygen isotope compositions of different stages of quartz vary from +5.6 to +9.3‰ and calculated ${\delta}^{18}O$ values of ore fluid at $250^{\circ}C$ range from -3.2 to +0.4‰, reflecting an isotopically evolved ore fluid mixed with a $^{18}O$ depleted meteoric water under the variable mixing ratios between hydrothermal and meteoric waters. Isotopic data of calcite minerals support the above conclusions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.351-354
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• 1998

The formation of the $YBa_2Cu_30_{7_\delta}$(Y123) thick films has been investigated by a surface diffusion Imcess between $3BaCu0_2$+2CuO composite coating powder and a $Y_2BaCuO_5$(Y211). This reaction has been studied in the temperature of $930^{\circ}C$ and $940^{\circ}C$ for 2h to 10h in an oxygen atmosphere. The Y211 substrates becomes covered by co-precipitation of Y123 grains and CuO inclusions. X-ray diflractotnctn. revealed that the lager consisted of an orthorhombic crystal structure. The maximum Jc of $400A/\textrm{cm}^2$ is abtained when the specimen was heat-treated at $930^{\circ}C$ for 6h on the Y211 substrate.

• Economic and Environmental Geology
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• v.20 no.3
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• pp.169-177
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• 1987

The Manjang copper magnetite-fluorite orebodies are imbedded within the limestone beds of the Hwajonri Formation. The ore deposits are characterized by magnetite-fluorite bearing skarn orebody in the west orebody and copper sulfide veins of the central and main orebodies. This study includes fluid inclusion geothermometry, salinity analysis, stable isotope analysis, and application of phase rule to mineral associations in skarn ore. Ore minerals are closely associated with the skarn silicates such as garnet, wollastonite and epidote. Magnetite and fluorite are remarkable in the west orebody whereas chalcopyrite is dominate in the central and main orebodies where pyrite and pyrrhotite also appear as sulfide gangues. Homogenization temperature and salinity of fluid inclusions are measured ranging between $240^{\circ}C$ and $350^{\circ}C$, 6.3~12.9 wt. percent in quartz and $220^{\circ}C$ and $350^{\circ}C$, 8.5~9.9wt. percent in fluorite, respectively. This indicates that the filling temperature and salinity are higher in quartz than in fluorite with the tendency of both to be linearly decreased suggesting an attribution of meteoric water to the mineralization. $T-fo_2$ diagram in the Ca-Fe-Si system at 1 kb and $Xco_2$=0.02 shows that the mineral assemblages with decreasing temperature are andradite-hedenbergite-calcite, hedenbergite-andradite-quartz, magnetite-andradite-quartz, and magnetite-quartz-calcite, indicating that magnetite crystallizes mostly late skarn stage at lower temperature. According to the carbon and oxygen isotopic values of the host limestone and calcite in ores, the sourec of carbon might be mixture of host limestone and deep seated carbons. Sulfur isotope data imply that ore fluids be relatively homogeneous in sulfur isotopic composition, mainly derived from igneous source.

• Journal of Microbiology and Biotechnology
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• v.31 no.6
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• pp.890-901
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• 2021

The 11α-hydroxylation of canrenone can be catalyzed by Aspergillus ochraceus in bioreactors, where the geometry of the impeller greatly influences the biotransformation. In this study, the effects of the blade number and impeller diameter of a Rushton turbine on the 11α-hydroxylation of canrenone were considered. The results of fermentation experiments using a 50 mm four-blade impeller showed that 3.40% and 11.43% increases in the conversion ratio were achieved by increasing the blade number and impeller diameter, respectively. However, with an impeller diameter of 60 mm, the conversion ratio with a six-blade impeller was 14.42% lower than that with a four-blade impeller. Data from cold model experiments with a large-diameter six-blade impeller indicated that the serious leakage of inclusions and a 22.08% enzyme activity retention led to a low conversion ratio. Numerical simulations suggested that there was good gas distribution and high fluid flow velocity when the fluid was stirred by large-diameter impellers, resulting in a high dissolved oxygen content and good bulk circulation, which positively affected hyphal growth and metabolism. However, a large-diameter six-blade impeller created overly high shear compared to a large-diameter four-blade impeller, thereby decreasing the conversion ratio. The average shear rates of the former and latter cases were 43.25 s^-1 and 35.31 s^-1, respectively. We therefore concluded that appropriate shear should be applied in the 11α-hydroxylation of canrenone. Overall, this study provides basic data for the scaled-up production of 11α-hydroxycanrenone.

• Economic and Environmental Geology
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• v.24 no.2
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• pp.131-150
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• 1991

The Weolseong diatreme was temporally and spatially related to the intrusion of the Gadaeri granite, and was -mineralized by meteoric aqueous fluids. In the Nokdong As-Zn deposit, pyrite, aresenopyrite and sphalerite are the most abundant sulfide minerals. They are associated with minor amount of magnetite, pyrrhotite, chalcopyrite and cassiterite, and trace amounts of Pb-Sb-Bi-Ag sulphosalts. The AsZn ore probably occurred at about $350^{\circ}C$ according to fluid inclusion and compositional data estimated from the arsenic content of arsenopyrite and iron content of sphalerite intergrown with pyrrhotite + chalcopyrite + cubanite. Heating studies of fluid inclusions in quartz indicate a temperature range between 180 and $360^{\circ}C$, and freezing data indicate a salinity range from 0.8 to 4.1 eq.wt % NaCl. The coexisting assemblage pyrite + pyrrhotite + arsenopyrite suggests that $H_2S$ was the dominate reduced sulfur species, and defines fluid parameter thus: $10^{-34.5}$ < ${\alpha}_{S_2}$ < $10^{-33}$, $10^{-11}$ < $f_{S_2}$ < $10^{-8}$, -2.4 < ${\alpha}_{S_2}$ < -1.6 atm and pH= 5.2 (sericte stable) at $300^{\circ}C$. The sulfur isotope values ranged from 1.8 to 5.5% and indicate that the sulfur in the sulfides is of magmatic in origin. The carbon isotope values range from -7.8 to -11.6%, and the oxygen isotope values from the carbonates in mineralized wall rock range from 2 to 11.4%. The oxygen isotope compositions of water coexisting with calcite require an input of meteoric water. The geochemical data indicate that the ore-forming fluid probably was generated by a variety of mechanisms, including deep circulation of meteoric water driven by magmatic heat, with possible input of magniatic water and ore component.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.75-87
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• 2003

The Haman-Gunbuk mineralized area is located within the Cretaceous Gyeongsang Basin along the southeastern part of the Korean peninsula. Major ore minerals, magnetite, scheelite, molybdenite and chalcopyrite, together with base-metal sulfides and minor sulfosalts, occur in fissure-filling tourmaline, quartz and carbonates veins contained within Cretaceous sedimentary and volcanic rocks anu/or granodiorite (118{\pm}$3.0 Ma). The ore and gangue mineral paragenesis can be divided into three distinct stages: Stage 1, tourmaline+quartz+Fe-Cu ore mineralization; Stage II, quartz+sulfides+sulfosalts+carbonates; Stage 111, barren calcite. Earliest fluids are recorded in stage I and early por-tions of stage II veins as hypersaline (35~70 equiv. wt.% NaCl+KCl) and vapor-rich inclusions which homogenize from ~30$0^{\circ}C$ to $\geq$50$0^{\circ}C$. The high-salinity fluids are complex chloride brines with significant concentrations of sodium, potassium, iron, copper, and sulfur, though sulfide minerals are not associated with the early mineral assemblage produced by this fluid. Later solutions circulated through newly formed fractures and reopened veins, and are recorded as lower-salinity(less than ~20 equiv. wt.% NaCl) fluid inclusions which homogenize primarily from ~200 to 40$0^{\circ}C$. The oxygen and hydrogen isotopic compositions of fluid in the Haman-Gunbuk hydrothermal system represents a progressive shift from magmatic-hydrothermal dominance during early mineralization stage toward meteoric-hydrothermal dominance during late mineralization stage. The earliest hydrothermal fiuids to circu-late within the granodiorite stock localiring the ore body at Haman-Gunbuk could have exsolved from the crystal-lizing magma and unmixed into hypersaline liquid and $H_2O$-NaCl vapor. As these magmatic fluids moved throughfractures, tourmaline and early Fe, W, Mo, Cu ore mineralization occurred without concomitant deposition of othersulfides and sulfosalts. Later solutions of dominantly meteoric origin progressively formed hypogene copper and base-metal sulfides, and sulfosalt mineralization.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.395-405
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• 2009

The maturity of amber matrix and inclusion was studied to explore the effect of heat treatment on the formation of the sun spangle in the transparent Baltic amber from Gdansk, Poland. Optical microscope revealed two types of inclusions in the original amber samples. The inclusions in the amber which had sun spangle were dramatically expanded by the heat treatment, comparing to those without sun spangle which contains fissure and shows different refractive index. The amber sample which didn't show sun spangle after the heat treatment showed a strong carbon related peak in TOF-SIMS spectra and weak oxygen related peak. it means that the maturity of this amber sample is comparatively higher than the one with spangle. The two amber samples show similar IR spectra before the heat treatment. However, the amber which had sun spangle exhibited an additional 1019 $cm^{-1}$ absorption peak and a more intense 887 $cm^{-1}$ peak. The different chemical compositions between the two types of amber is believed to be due to the different absorption spectra between 1000~600 $cm^{-1}$. According to the study of DSC analysis, the two samples show different DSC profiles. Although they have the same geological origin, their geological ages are different and have different chemical compositions. Thus, they exhibited different behavior after the heat treatment. The formation of sun spangle seemed to depend on the difference in the heat expansion rate of amber matrix with different maturity and chemical compositions.

• Economic and Environmental Geology
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• v.32 no.2
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• pp.129-139
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• 1999

Hydrothermal gold deposits of the Trabong district in Vietnam occur as single-stage quartz $\pm$ calcite veins (0.3-1.2 m thick) which fill fault fractures in graphite-bearing gneiss and schist of the Chulai Complex and Kham Duc Formation of the Proterozoic age. Ore grades are 1.3 to 92.4 g/ton Au. Ore mineralogy is very simple, consisting mainly of pyrite with minor amounts of base-metal sulfides and electrum. Gold grains occur in two assemblages as follows: (1) early, Fe-rich (7.2-10.4 mole % FeS) sphalerite + electrum (50.4-64.3 atom % Au) assemblage occurring as inclusions in pyrite; (2) late, Fe-poor «4.7 mole % FeS) sphalerite + galena + electrum (47.6-81.7 atom % Au) assemblage occurring along fractures of pyrites. Based on fluid inclusion data and thermochemical considerations of ore mineral assemblages, ore minerals were formed at high temperatures (about $230^{\circ}C$ to $420^{\circ}C$) from $H_{2}O-CO_{2}(-CH_{4})$-NaCI fluids with the sulfur fugacity of about $10^{-6}$ to $10^{-10}$ atm. Fluid inclusion data also indicate that ore mineralization occurred mainly as a result of fluid unmixing accompanying $CO_2$ effervescence. Calculated oxygen and measured hydrogen isotope compositions of mineralizing waters (${\delta}^{18}O_{V-SMOW}$ values = 5.3 to 8.6$\textperthousand$, ${\delta}D_{V-SMOW}$ values = - 60 to - 52$\textperthousand$), along with the sulfur isotope compositions of vein sulfides (${\delta}^{34}S_{CDR}$ values = - 1.2 to 2.8$\textperthousand$) and carbon isotope compositions of inclusion $CO_2$ (${\delta}^{13}C_{PDB}$ values = - 4.7 to - 2.0$\textperthousand$) indicate that the high temperature (mesohypothermal) gold mineralization formed from a magmatic fluid.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.211-220
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• 2002

The Xiaoxinancha Cu-Au deposit in the Jilin province, located in NNE 800 km of Beijing, is hosted by diorite. The ore mineralization of Xiaoxinancha Cu-Au deposit show a stockwork occurrence that is concentrated on the potassic and phyllic alteration zones. The Xiaoxinancha Cu-Au deposit in the south is being mined with its reserves grading 0.8% Cu, 3.64 g/t Au and 16.8 g/t Ag and in the north, grading 0.63% Cu, 3.80 g/t Au and 6.8 glt Ag. The alteration assemblage occurs as a supergene blanket over deposit. Hydrothermal alteration at the Xiaoxinancha Cu-Au deposit is centered about the stock and was extensively related to the emplacement of the stock. Early hydrothermal alteration was dominantly potassic and followed by propylitic alteration. Chalcocite, often associated with hematite, account for the ore-grade copper, while chalcopyrite, bornite, quartz, epidote, chlorite and calcite constitute the typical gangue assemblage. Other minor opaque phases include pyrite, marcasite, native gold, electrum, hessite, hedleyite, volynskite, galenobismutite, covellite and goethite. Fluid inclusion data indicate that the formation of this porphyry copper deposit is thought to be a result of cooling followed by mixing with dilute and cooler meteoric water with time. In stage II vein, early boiling occurred at 497$^{\circ}$C was succeeded by the occurrence of halite-bearing type III fluid inclusion with homogenization temperature as much as 100$^{\circ}$C lower. The salinities of type 1II fluid inclusion in stage II vein are 54.3 to 66.9 wt.% NaCI + KCI equiv. at 383$^{\circ}$ to 495$^{\circ}$C, indicating the formation depth less than 1 km. Type I cupriferous fluids in stage III vein have the homogenization temperatures and salinity of 168$^{\circ}$ to 365$^{\circ}$C and 1.1 to 9.0 wt.% NaCI equiv. These fluid inclusions in stage III veins were trapped in quartz veins containing highly fractured breccia, indicating the predominance of boiling evidence. This corresponds to hydrostatic pressure of 50 to 80 bars. The $\delta$$^{34}S$ value of sulfide minerals increase slightly with paragenetic time and yield calculated $\delta$$^{34}S_{H2S}$ values of 0.8 to 3.7$\textperthousand$. There is no mineralogical evidence that fugacity of oxygen decreased, and it is thought that the oxygen fugacity of the mineralizing fluids have been buffered through reaction with magnetite. We interpreted the range of the calculated $\delta$$^{34}S_{H2S}$ values for sulfides to represent the incorporation of sulfur from two sources into the Xiaoxinancha Cu-Au hydrothermal fluids: (1) an isotopically light source with a $\delta$$^{34}S$ value of I to 2$\textperthousand$, probably a Mesozoic granitoid related to the ore mineralization. We can infer from the fact that diorite as the host rock in the Xiaoxinancha Cu-Au deposit area intruded plagiogranite; (2) an isotopically heavier source with a $\delta$$^{34}S$ value of > 4.0$\textperthousand$, probably the local porphyry.