• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.305-311
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• 2017

This study aimed to evaluate the fermentation characteristics of mixed Makgeolli with barley and wheats under, fermentation at different temperatures (20, 25, and $30^{\circ}C$) and time (3, 6, and 9 days). The pH and sugar of mixed Makgeolli were 3.68~4.26 and $12.30{\sim}17.31^{\circ}Brix$, respectively. The total acidity showed proportionate increase with fermentation temperature and time; whereas, reducing sugar contents decreased with increasing fermentation temperature and time. The alcohol contents of mixed Makgeolli varied significantly by fermentation temperature and time (p<0.05). In terms of color values, the L value decreased with increasing fermentation temperatures, and a value increased significantly with increasing fermentation time. The number of microorganisms (yeast, total bacteria and lactic acid bacteria) in mixed Makgeolli decreased progressively with increasing fermentation temperature and time. Among the organic acids (citric, lactic, malic, and pyruvic acids) in mixed Makgeolli, citric and lactic acid was present at the highest concentrations. From these results, the optimum fermentation conditions of mixed Makgeolli with barley and wheat were $20{\sim}25^{\circ}C$ for 6 days.

• Journal of Powder Materials
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• v.16 no.5
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• pp.316-325
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• 2009

Fe based (Fe$_{68.2}$C$_{5.9}$Si$_{3.5}$B$_{6.7}$P$_{9.6}$Cr$_{2.1}$Mo$_{2.0}$Al$_{2.0}$) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The experiment results show that the as-prepared Fe amorphous powders less than 90 $\mu$m in size has a fully amorphous phase and its weight fraction was about 73.7%. The as-atomized amorphous Fe powders had a complete spherical shape with very clean surface. Differential scanning calorimetric results of the as-atomized Fe powders less than 90 $\mu$m showed that the glass transition, T$_g$, onset crystallization, T$_x$, and super-cooled liquid range $\Delta$T=T$_x$-T$_g$ were 512, 548 and 36$^{\circ}C$, respectively. Fe amorphous powders were mixed and deformed well with 10 wt.% Cu by using AGO-2 high energy ball mill under 500 rpm.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.259-273
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• 1992

The Seongsan mine is one of the largest dickite deposits in the southwestern part of the Korean Peninsula. The main constithent minerals of the ore are dickite and quartz with accessory alunite, kaolinite and sericite. The geology around the Seongsan mine consists mainly of the late Cretaceous felsic volcanic rocks. In the studied area, these rocks make a synclinal structure with an axis of E-W direction plunging to the east. Most of the felsic volcanic rocks have undergone extensive hydrothermal alteration. The hydrothermally altered rocks can be classified into the following zones: Dickite, Dickite-Quartz, Quartz, Sericite, Albite and Chlorite zones, from the center to the margin of the alteration mass. Such zonal arrangement of altered rocks suggests that the country rocks, most of which are upper part of the rhyolite and welded tuff, were altered by strongly acid hydrothermal solutions. It is reasonable to consider that initial gas and solution containing $H_2S$ and other compounds were oxidized near the surface, and formed hydrothermal sulfuric acid solutions. The mineralogical and chemical changes of the altered rocks were investigated using various methods, and chemical composition of fifty-six samples of the altered rocks were obtained by wet chemical analysis and X.R.F. methods. On the basis of these analyses, it was found that some components such as $SiO_2$, $Al_2O_3$, $Fe_2O_3$, CaO, MgO, $K_2O$, $Na_2O$ and $TiO_2$ were mobilized considerably from the original rocks. The formation temperature of the deposits was estimated as higher than $200^{\circ}C$ from fluid inclusion study of samples taken from the Quartz zone. On the basis of the chemical composition data on rocks and minerals and estimated temperatures, the hydrothermal solutions responsible for the formation of the Seongsan dickite deposits were estimated to have the composition: $m_{K^+}=0.003$, $m_{Na^+}=0.097$, $m_{SiO_2(aq.)}=0.008$ and pH=5.0, here "m" represents the molality (mole/kg $H_2O$).

• KSBB Journal
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• v.32 no.2
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• pp.124-132
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• 2017

A methane-oxidizing bacterium was isolated from rice paddy field soil around Jeollanam-do province, Korea, and characterized. The isolate was gram-negative, orange pigmented and short rod ($1.1-1.2{\times}1.6-1.9{\mu}m$). It was catalase and urease-negative but oxidase-positive. The strain utilized methane and methanol as sole carbon and energy sources. It had an ability to grow with an optimum pH 7.0 and an optimum growth temperature $30^{\circ}C$. The strain was resistant to antibiotic polymyxin B but sensitive to streptomycin, kanamycin, ampicillin, chloramphenicol and rifampicin. The isolate required copper for their growth with concentration range of $2-25{\mu}M$, with an optimum of $10{\mu}M$. Under optimal culture condition, specific cell growth rate and generation time were found to be $0.046hr^{-1}$ and 15.13 hr, respectively. Phylogenetic analysis based on 16S rDNA sequences indicated that the strain formed a tight phylogenetic lineage with Methylomonas koyamae with a value of 99.4% gene sequence homology. So, we named the isolate as Methylomonas sp. SM4. 8.6 mM methanol was accumulated in the reaction mixture containing 70 mM sodium formate and 40 mM $MgCl_2$ (MDH inhibitor) under atmosphere of methane:air (40:60) mixture for 24 hr at $30^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1180-1185
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• 2006

Lab-scale batch experiments using several 25-L transparent acrylic reactors were conducted to develop optimum capping materials that can reduce phosphorus released from polluted sediments. The sediment used in the experiment was very fine clay(8.8 $\Phi$ in mean grain size), and organic carbon($C_{org}$) content was as high as 2%. Four kinds of batches with different capping materials Brucite($Mg(OH)_2$), Sea sand($SiO_2$), Granular-gypsum($CaSO_4{\cdot}2H_2O$), Double layer(brucite+sand), and one control batch were operated for 30 days. Phosphorus fluxes released from bottom sediments in the control batch were estimated to be 14.6 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, while 9.5 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 5.2 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 4.2 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, and 3.1 $mg{\cdot}m^{-2}{\cdot}d^{-1}$ in the batch capped with Sea sand, Granular-gypsum, Double layer, and Brucite, respectively. The results obtained from lab-scale batch experiments show that there were 70% reduction of phosphorus for some materials such as Brucite, Double layer(brucite+sand), and whereas sea sand only about 35%. The pH range of surface sediment to which Brucite was applied showed about $8.0{\sim}9.5$ in the weak alkaline state. This effect can prevent liberation of $H_2O$. The addition of gypsum into the sediment can reduce the progress of methanogenesis because of fast early diagenesis and sufficient supply of $SO_4^{2-}$ to the sediments, stimulate the SRB highly. Therefore, the application of Brucite and Gypsum can reduce phosphorus release from the sediment as a result of formation of $Mg_5(OH)(PO_4)_3$, pyrite($FeS_x$), and apatite-mineral.

• Ocean and Polar Research
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• v.26 no.3
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• pp.401-414
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• 2004

Temperature, salinity, alkalinity, pH, nutrient, chlorophyll, and iron were measured within the upper 250m water column around the Antarctic Polar Front in the Scotia Sea from late November to early December 2001. Temperature and salinity showed a rapid change across the Polar Front, and the temperature minimum layer existed only in the southern area of the Polar Front. Total $CO_2$ and nutrient concentrations were relatively high and increased rapidly with water depth in the southern area of the Polar Front, which was resulted from upwelling of the Antarctic deep water containing high concentrations of total $CO_2$ and nutrient. ${\Delta}C:{\Delta}N:{\Delat}P$ ratios measured in the norhem and southern areas of the Polar Front were 75:11.4:1 and 84:12.5:1, respectively, which were lower than the Redfield ratio. ${\Delta}Si:{\Delta}N$ ratio (3.65) measured in the southern area of the Polar Front was two times higher than that (1.95) in the northern area. These two ratios were higher than the ratio (1.0) measured in the temperate and tropical oceans. Chlorophyll concentrations were extremely high in the area of $59^{\circ}{\sim}60^{\circ}S$, which was attributed to favorable environmental conditions for phytoplankton growth in this area, such as sufficient iron, high water column stability, and high silicate concentration.

• Journal of Photoscience
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• v.12 no.1
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• pp.17-23
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• 2005

Application of a new photocatalyst has been attempted to improve the efficiency and rates of photocatalytic degradation of azo dyes by using a model dye such as Methyl Orange. As a new photocatalyst, $TiO_2$ encapsulated EFAL-removed zeolite Y ($TiO_2$ /EFAL-removed zeolite Y) has been synthesized by ion-exchange in the mixture of EFAL-removed zeolite Y with 0.05 M aqueous [$(NH_4)_2 TiO(C_2O_4)_2.H_2O$] [$TiO(C_2O_4)_2.H_2O$]. This new photocatalyst has been characterized by measuring XRD, IR and reflectance absorption spectra as well as ICP analysis, and it was found that the framework structure of $TiO_2$ /EFAL-removed zeolite Y is not changed by removing the extra-framework aluminum (EFAL) from the normal zeolite Y and the $TiO_2$ inside the photocatalyst exists in the form of $(TiO^{2+})_n$ nanoclusters. Based on the ICP analysis, the Si/Al ratio of the $TiO_2$ /EFAL-removed zeolite Y and the weight of $TiO_2$ were determined to be 23 and 0.061g in 1.0g photocatalyst, respectively. It was also found that adsorption of the azo dye in the $TiO_2$ /EFAL-removed zeolite is very effective (about 80 % of the substrate used). This efficient adsorption contributes to the synergistic photocatalytic activities of the $TiO_2$ /EFAL-removed zeolite by minimizing the required flux diffusion of the substrate. Thus, the photocatalytic reduction of methyl orange (MO) was found to be 8 times more effective in the presence of $TiO_2$ /EFAL-removed zeolite Y than in the presence of $TiO_2$ /normal zeolite Y. Furthermore, the photocatalytic reduction of MO by using 1.0 g of the $TiO_2$ /EFAL-removed zeolite Y containing 0.061g of $TiO_2$ is much faster than that carried out by using 1.0 g of Degussa P-25.

• Journal of Ginseng Research
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• v.40 no.2
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• pp.185-195
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• 2016

Background: To investigate the effect of pectinase-treated Panax ginseng (GINST) in cellular and male subfertility animal models. Methods: Hydrogen peroxide ($H_2O_2$)-induced mouse spermatocyte GC-2spd cells were used as an in vitro model. Cell viability was measured using MTT assay. For the in vivo study, GINST (200 mg/kg) mixed with a regular pellet diet was administered orally for 4 mo, and the changes in the mRNA and protein expression level of antioxidative and spermatogenic genes in young and aged control rats were compared using real-time reverse transcription polymerase chain reaction and western blotting. Results: GINST treatment ($50{\mu}g/mL$, $100{\mu}g/mL$, and $200{\mu}g/mL$) significantly (p < 0.05) inhibited the $H_2O_2$-induced ($200{\mu}M$) cytotoxicity in GC-2spd cells. Furthermore, GINST ($50{\mu}g/mL$ and $100{\mu}g/mL$) significantly (p < 0.05) ameliorated the $H_2O_2$-induced decrease in the expression level of antioxidant enzymes (peroxiredoxin 3 and 4, glutathione S-transferase m5, and glutathione peroxidase 4), spermatogenesis-related protein such as inhibin-${\alpha}$, and specific sex hormone receptors (androgen receptor, luteinizing hormone receptor, and follicle-stimulating hormone receptor) in GC-2spd cells. Similarly, the altered expression level of the above mentioned genes and of spermatogenesis-related nectin-2 and cAMP response element-binding protein in aged rat testes was ameliorated with GINST (200 mg/kg) treatment. Taken together, GINST attenuated $H_2O_2$-induced oxidative stress in GC-2 cells and modulated the expression of antioxidant-related genes and of spermatogenic-related proteins and sex hormone receptors in aged rats. Conclusion: GINST may be a potential natural agent for the protection against or treatment of oxidative stress-induced male subfertility and aging-induced male subfertility.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.421-430
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• 2014

In this study, a series of autoclave experiments were conducted in order to investigate the geochemical and mineralogical effects of carbon dioxide on deep subsurface environments. High pressure and temperature conditions of $50^{\circ}C$ and 100 bar, which are representative environments for geological $CO_2$ sequestration, were created in stainless-steel autoclaves for simulating the interactions in the $scCO_2$-groundwater-mineral reaction system. Zeolite, a widespread mineral in Pohang Basin where many researches have been focused as a candidate for geological $CO_2$ sequestration, and groundwater sampled from an 800 m depth aquifer were applied in the experiments. Geochemical and mineralogical alterations after 30 days of $scCO_2$-groundwater-zeolite sample reactions were quantitatively examined by XRD, XRF, and ICP-OES investigations. The results suggested that dissolution of zeolite sample was enhanced under the acidic condition induced by dissolution of $scCO_2$. As the cation concentrations released from zeolite sample increase, $H^+$ in groundwater was consumed and pH increases up to 10.35 after 10 days of reaction. While cation concentrations showed increasing trends in groundwater due to dissolution of the zeolite sample, Si concentrations decreased due to precipitation of amorphous silicate, and Ca concentrations decreased due to cation exchange and re-precipitation of calcite. Through the reaction experiments, it was observed that introduction of $CO_2$ could make alterations in dissolution characteristics of minerals, chemical compositions and properties of groundwater, and mineral compositions of aquifer materials. Results also showed that geochemical reactions such as cation exchange or dissolution/precipitation of minerals could play an important role to affect physical and chemical characteristics of geologic formations and groundwater.

• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.75-84
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• 2010

This study was performed to investigate change in chemical composition of Acer mono saps collected in Hamyang, Inje, Namyangju and Yeongwol depending on storing period. pH of A. mono sap was in the range of 4.43~5.68, and it was decreased rapidly with the increase of storing period. A. mono sap collected in Yeongwol in Feb. 22 contained 2.06% sucrose. Degradation of sucrose was occurred when storing period was extended, and it caused production of organic acid like pyruvic acid, lactic acid, acetic acid and ethanol. Detected minerals in A. mono sap were K, Ca, Na, Mg, P, Si, Al, Mn, Fe, Cu and Zn, however, K and Ca content reached 93%. A. mono sap collected in Inje in Mar. 03 contained 131.72 mg/${\ell}$, which was especially high K content among the A. mono sap. 1.55~3.50 mg/${\ell}$ of Ascorbic acid was found in the A. mono sap. Sap collected in early date was less degraded.