• Plant Journal
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• v.18 no.4
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• pp.58-65
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• 2023

In this study, to increase the methane content of biogas supplied from Nanji Water Regeneration Center and to purify impurities, a three-stage membrane purification process was designed and installed to demonstrate operation. The methane concentration of biomethane produced in the 2 Nm3/h purification process was set to three cases: 95%, 96.5%, and 98%, and the membrane area ratio of the membrane was 1:1, 1:2, 1:1:1, The optimum conditions for the membrane area of the separator were derived by changing to five of 1:2:1 and 1:2:2. 3 stage separation membrane process of 30 Nm3/h was installed to reflect the optimum condition of 2 Nm3/h, and biomethane production of 98% or more of methane concentration was demonstrated. As a result of the operation of the 2 Nm³/h refining device, the methane recovery rate at the 98% methane concentration was 95.6% when the membrane area ratio was 1:1 as the result of the two-stage operation of the separator, and the recovery rate of methane at 1:2 was increased to 96.8%. The methane recovery rate of the membrane three-stage operation was highest at 96.8% when the membrane area ratio was operated at 1:2:1. The carbon dioxide removal rate was 16.4 to 96.4% and the 2:2 to 95.7% film area ratio in the two-step process. In the three-step process, the film area ratio was 1:2:1 to 95.4%, and the two-step process showed higher results than the three-step process. In the 30 Nm3/h scale biogas purification demonstration operation, the methane concentration after purification was 98%, the recovery rate of methane was 97.1%, the removal rate of carbon dioxide was 95.7%, and hydrogen sulfide, the cause of corrosion, was not detected, and the membrane area ratio was 1:2:1 demonstration operation, biomethane production with a methane concentration of 98% or higher was possible.

• Conservation Science in Museum
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• v.29
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• pp.1-32
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• 2023

The Paintings of a 60^th Wedding Anniversary Ceremony Created by an Unknown Painter (Deoksu 6375), housed by the National Museum of Korea, is a five-panel painting book depicting scenes from a wedding ceremony. Hoehonrye is a type of repeated wedding ceremony to commemorate a couple's 60th wedding anniversary with congratulations from the community. The paintings of the book record five scenes from the wedding: jeoninrye, a ceremony where the groom brings a wooden wild goose to the bride's house; gyoberye, the groom and the bride bowing to each other; heosurye, pouring liquor to toast to the couple's longevity; jeopbin, offering tea to guests; and a banquet to celebrates the couple's 60th wedding anniversary. The book describes figures, buildings and a variety of items in detail with delicate brushstrokes. The techniques were examined using microscopy, infrared, and X-ray irradiation and hyperspectral imaging analysis. The invisible parts were examined to identify the rough sketch and distinguish pigments and dyes used for each color. The components of the pigments were determined by X-ray fluorescence analysis, while the dyes were identified by UV-vis spectrometry. Microscope observation revealed that the fabric used for the paintings was raw silk thread with almost no fiber twist, and plain silk fabric. Hyperspectral imaging analysis, X-ray fluorescence analysis, and UV-vis spectrometry confirmed that the white pigment was white lead and the black was chinese ink. The red pigments were using red clay, cinnabar, and a mixture of cinnabar and minium. Brown was made using red clay and organic dyes, and yellow using gamboge. Green was identified as indigo, malachite, chrome green, barium sulfide, and blue as azurite, smalt, and indigo. The purple dye was estimated as a mixture of indigo and cochineal, and gold parts were used gold powder. Hyperspectral images were distinguished parts damaged and conservation treatment area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.213-228
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• 2009

This study was conducted to investigate spatio-temporal changes in macrobenthic community structure and benthic environmental conditions in Geoje-Hansa Bay, which is the greatest oyster producing site in Korea. Field survey for benthic environment and macrobenthos was seasonally carried out at 15 stations covering oyster farming sites and non-farming sites from February to November, 2008. The grain size of surface sediments was dominated by very fine silt with the mean phi of about $9\;{\Phi}$ and TOC was 1.9% on average. Mean dissolved oxygen content was 8.1 mg/L and lowest in August corresponding to the 2nd degree in seawater quality criteria. Total species number was 351 and mean density was $3,675\;ind./m^2$, both of which were dominated by polychaete worms. Spatio-temporal variation in above two biological variables was great with higher values seasonally in spring and spatially in channels rather than inner bay. Dominant species were Lumbrineris longifolia (21.3%), Aphelochaeta monilaris (17.8%) and Ericthonius pugnax(6.1%), all of which are typical species of organically enriched area. From the multivariate analyses, the whole macrobenthic community was distinguished into two groups of channel and inner bay group. Spatio-temporal changes of macrobenthic community in Geoje-Hansan Bay were related to those of TOC and acid volatile sulfide (AVS). Our results showed that Geoje-Hansan Bay should be intermediately affected by organic pollution, and that such organic enrichment was more remarkable at farming stations in the inner bay.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.379-393
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• 2002

Within the Boseong-Jangheung area of Korea, five hydrothermal gold (-silver) quartz vein deposits occur. They have the characteristic features as follows: the relatively gold-rich nature of e1ectrurns; the absence of Ag-Sb( -As) sulfosalt mineral; the massive and simple mineralogy of veins. They suggest that gold mineralization in this area is correlated with late Jurassic to Early Cretaceous, mesothermal-type gold deposits in Korea. Fluid inclusion data show that fluid inclusions in stage I quartz of the mine area homogenize over a wide temperature range of 200$^{\circ}$ to 460$^{\circ}$C with salinities of 0.0 to 13.8 equiv. wt. % NaCI. The homogenization temperature of fluid inclusions in stage II calcite of the mine area ranges from 150$^{\circ}$ to 254$^{\circ}$C with salinities of 1.2 to 7.9 equiv. wt. % NaCI. This indicates a cooling of the hydrothermal fluid with time towards the waning of hydrothermal activity. Evidence of fluid boiling including CO2 effervescence indicates that pressures during entrapment of auriferous fluids in this area range up to 770 bars. Calculated sulfur isotope composition of auriferous fluids in this mine area (${\delta}^34S$_{{\Sigma}S}$$\textperthousand$) indicates an igneous source of sulfur in auriferous hydrothermal fluids. Within the Sobaegsan Massif, two representative mesothermal-type gold mine areas (Youngdong and Boseong-Jangheung areas) occur. The ${\delta}^34S values of sulfide minerals from Youngdong area range from -6.6 to 2.3$\textperthousand$ (average=-1.4$\textperthousand$, N=66), and those from BoseongJangheung area range from -0.7 to 3.6$\textperthousand$ (average=1.6$\textperthousand$, N=39). These i)34S values of both areas are comparatively lower than those of most Korean metallic ore deposits (3 to 7TEX>$\textperthousand$). And, within the Sobaegsan Massif, the ${\delta}^34S values of Youngdong area are lower than those of Boseong-Jangheung area. It is inferred that the difference of ${\delta}^34S values within the Sobaegsan Massif can be caused by either of the following mechanisms: (1) the presence of at least two distinct reservoirs (both igneous, with ${\delta}^34S values of < -6 $\textperthousand$ and 2$\pm$2 %0) for Jurassic mesothermal-type gold deposits in both areas; (2) different degrees of the mixing (assimilation) of 32S-enriched sulfur (possibly sulfur in Precambrian pelitic basement rocks) during the generation and/or subsequent ascent of magma; and/or (3) different degrees of the oxidation of an H2S-rich, magmatically derived sulfur source ${\delta}^34S = 2$\pm$2$\textperthousand$) during the ascent to mineralization sites. According to the observed differences in ore mineralogy (especially, iron-bearing ore minerals) and fluid inclusions of quartz from the mesothermal-type deposits in both areas, we conclude that pyrrhotite-rich, mesothermal-type deposits in the Youngdong area formed from higher temperatures and more reducing fluids than did pyrite(-arsenopyrite)-rich mesothermal-type deposits in the Boseong-Jangheung area. Therefore, we prefer the third mechanism than others because the ${\delta}^34S values of the Precambrian gneisses and Paleozoic sedimentary rocks occurring in both areas were not known to the present. In future, in order to elucidate the provenance of ore sulfur more systematically, we need to determine ${\delta}^34S values of the Precambrian metamorphic rocks and Paleozoic sedimentary rocks consisting the basement of the Korean Peninsula including the Sobaegsan Massif.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.1
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• pp.1-13
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• 2006

A field survey on the spatio-temporal distribution characteristics and origins of organic matter in surface sediments was carried out monthly at six stations in Gamak Bay, South Korea from April 2000 to March 2002. The range of ignition loss(IL) was $4.6{\sim}11.6%(7.1{\pm}1.6%)$, while chemical oxygen demand(CODs) ranged from $12.25{\sim}99.26mgO_2/g-dry(30.98{\pm}19.09mgO_2/g-dry)$, acid volatile sulfide(AVS) went from no detection(ND)${\sim}10.29mgS/g-dry(1.02{\pm}0.58mgS/g-dry)$, and phaeopigment was $6.84{\sim}116.18{\mu}g/g-dry(23.72{\pm}21.16{\mu}g/g-dry)$. The ranges of particulate organic carbon(POC) and particulate organic nitrogen(PON) were $5.45{\sim}23.24 mgC/g-dty(10.34{\pm}4.40C\;mgC/g-dry)$ and $0.71{\sim}2.99mgN/g-dry(1.37{\pm}0.58mgN/g-dry)$, respectively. Water content was in the range of $43.1{\sim}77.6%(55.8{\pm}5.6%)$, and mud content(silt+clay) was higher than 95% at all stations. The spatial distribution of organic matter in surface sediments was greatly divided between the northwestern, central and eastern areas, southern entrance area from the distribution characteristic of their organic matters. The concentrations of almost all items were greater at the northwestern and southern entrance area than at the other areas in Gamak Bay. In particular, sedimentary pollution was very serious at the northwestern area, because the area had an excessive supply of organic matter due to aquaculture activity and the inflow of sewage from the land. These materials stayed longer because of the topographical characteristics of such as basin and the anoxic conditions in the bottom seawater environment caused by thermocline in the summer. The tendency of temporal change was most prominently in the period of high-water temperatures than low-water ones at the northwestern and southern entrance areas. On the other hand, the central and eastern areas did not show a regular trend for changing the concentrations of each item but mainly showed a higher tendency during the low-water temperatures. This was observed for all but AVS concentrations which were higher during the period of high-water temperature at all stations. Especially, the central and eastern areas showed a large temporal increase of AVS concentration during those periods of high-water temperature where the concentration of CODs was in excess of $20mgO_2/g-dry$. The results show that the organic matters in surface sediments in Gamak Bay actually originated from autochthonous organic matters with eight or less in average C/N ratio including the organic matters generated by the use of ocean, rather than terrigenous organic matters. However, the formation of autochthonous organic matter was mainly derived from detritus than living phytoplankton, indicated the results of the POC/phaeopigment ratio. In addition, the CODs/IL ratio results demonstrate that the detritus was the product of artificial activities such as dregs feeding and fecal pellets of farm organisms caused by aquaculture activities rather than the dynamic of natural ocean activities.

• Economic and Environmental Geology
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• v.25 no.4
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• pp.417-433
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• 1992

Lead-zinc-copper deposits of the Jeonheung and the Oksan mines around Euiseong area occur as hydrothermal quartz and calcite veins that crosscut Cretaceous sedimentary rocks of the Gyeongsang Basin. The mineralization occurred in three distinct stages (I, II, and III): (I) quartz-sulfides-sulfosalts-hematite mineralization stage; (II) barren quartz-fluorite stage; and (III) barren calcite stage. Stage I ore minerals comprise pyrite, chalcopyrite, sphalerite, galena and Pb-Ag-Bi-Sb sulfosalts. Mineralogies of the two mines are different, and arsenopyrite, pyrrhotite, tetrahedrite and iron-rich (up to 21 mole % FeS) sphalerite are restricted to the Oksan mine. A K-Ar radiometric dating for sericite indicates that the Pb-Zn-Cu deposits of the Euiseong area were formed during late Cretaceous age ($62.3{\pm}2.8Ma$), likely associated with a subvolcanic activity related to the volcanic complex in the nearby Geumseongsan Caldera and the ubiquitous felsite dykes. Stage I mineralization occurred at temperatures between > $380^{\circ}C$ and $240^{\circ}C$ from fluids with salinities between 6.3 and 0.7 equiv. wt. % NaCl. The chalcopyrite deposition occurred mostly at higher temperatures of > $300^{\circ}C$. Fluid inclusion data indicate that the Pb-Zn-Cu ore mineralization resulted from a complex history of boiling, cooling and dilution of ore fluids. The mineralization at Jeonheung resulted mainly from cooling and dilution by an influx of cooler meteoric waters, whereas the mineralization at Oksan was largely due to fluid boiling. Evidence of fluid boiling suggests that pressures decreased from about 210 bars to 80 bars. This corresponds to a depth of about 900 m in a hydrothermal system that changed from lithostatic (closed) toward hydrostatic (open) conditions. Sulfur isotope compositions of sulfide minerals (${\delta}^{34}S=2.9{\sim}9.6$ per mil) indicate that the ${\delta}^{34}S_{{\Sigma}S}$ value of ore fluids was ${\approx}8.6$ per mil. This ${\delta}^{34}S_{{\Sigma}S}$ value is likely consistent with an igneous sulfur mixed with sulfates (?) in surrounding sedimentary rocks. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values. Equilibrium thermodynamic interpretation indicates that the temperature versus $fs_2$ variation of stage I ore fluids differed between the two mines as follows: the $fs_2$ of ore fluids at Jeonheung changed with decreasing temperature constantly near the pyrite-hematite-magnetite sulfidation curve, whereas those at Oksan changed from the pyrite-pyrrhotite sulfidation state towards the pyrite-hematite-magnetite state. The shift in minerals precipitated during stage I also reflects a concomitant $fo_2$ increase, probably due to mixing of ore fluids with cooler, more oxidizing meteoric waters. Thermodynamic consideration of copper solubility suggests that the ore-forming fluids cooled through boiling at Oksan and mixing with less-evolved meteoric waters at Jeonheung, and that this cooling was the main cause of copper deposition through destabilization of copper chloride complexes.

• 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.