• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.485-494
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• 2018

This study aims to identify the characteristics of oxidation and chemical composition of PM in winter season, 2017 at Incheon area. The mean concentration of air pollutants were $46{\pm}22{\mu}g/m^3-PM_{10}$, $29{\pm}18{\mu}g/m^3/-PM_{2.5}$, $5{\pm}3ppb-SO_2$, $0.56{\pm}0.24ppm-CO$, $21{\pm}13ppb-O_3$ and $28{\pm}17ppb-NO_2$, respectively. The dominant ion of the $PM_{1.0}$ chemical component were organic with $3.2{\mu}g/m^3$ and nitrate with $1.9{\mu}g/m^3$. The day and night variation of the $PM_{1.0}$ chemical components was higher in nighttime than those of daytime. The averaged nitrate oxidation rate (SOR) was 0.06 and sulfate oxidation rate was 0.11 during the field campaign. In the high mass loading period, nitrate oxidation rate (NOR) was up to 0.6 and also the nitrate in $PM_{1.0}$ was increased. The averaged ratio of $NO_x/SO_2$ was 8.7 and nitrate/sulfate was 3.1, respectively. In this results, the nitrate component in $PM_{1.0}$ was influenced by NOx from the stationary source as power plant and the mobile source around the measurement site.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.111-123
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• 2022

Carbonate green rust (CGR) and sulfate green rust (SGR) commonly occur in nature. In this study, CGR and SGR were synthesized through co-precipitation, and their formation mechanisms and physicochemical properties were investigated. X-ray diffraction (XRD) and Rietveld refinement showed both CGR and SGR with layered double hydroxide structure were successfully synthesized without any secondary phases under each synthetic condition. Refined structural parameters (unit cell) for two green rusts were a (=b) = 3.17 Å and c = 22.52 Å for CGR and a (=b) = 5.50 Å and c = 10.97 Å for SGR with the crystallite size 57.8 nm in diameter from (003) reflection and 40.1 nm from (001) reflections, respectively. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) results showed that both CGR and SGR had typical hexagonal plate-like crystal morphologies but their chemical composition is different in the content of C and S. In addition, Fourier transform infrared (FT-IR) spectroscopy analysis revealed that carbonate (CO₃^2-) and sulfate (SO₄^2-) molecules were occupied as interlayer anions of CGR and SGR, respectively. These SEM/EDS and FT-IR results were in good agreement with XRD results. Changes in the solution chemistry (i.e., pH, Eh and residual iron concentrations (Fe(II):Fe(III)) of the mixed solution) were observed as a function of the injection time of hydroxyl ion (OH^-) into the iron solution. Three different stages were observed in the formation of both CGR and SGR; precursor, intermediator, and green rust in the formation of both CGR and SGR. This study provides co-precipitation methods for CGR and SGR in a way of the stable synthesis. In addition, our findings for the formation mechanisms of the two green rusts and their physicochemical properties will provide crucial information with researches and industrials in utilizing green rust.

• Journal of Sericultural and Entomological Science
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• v.16 no.1
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• pp.21-48
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• 1974

The studies were carried out to disclose the physical and chemical properties of sericin fraction obtained from silk cocoon shells and its characteristics of swelling and solubility. The following results were obtained. 1. The physical and chemical properties of sericin fraction. 1) In contrast to the easy water soluble sericin, the hard soluble sericin contains fewer amino acids include of polar side radical while the hard soluble amino acid sach as alanine and leucine were detected. 2) The easy soluble amino acids were found mainly on the outer part of the fibroin, but the hard soluble amino acids were located in the near parts to the fibroin. 3) The swelling and solubility of the sericin could be hardly assayed by the analysis of the amino acid composition, and could be considered to tee closely related to the compound of the sericin crystal and secondary structure. 4) The X-ray patterns of the cocoon filament were ring shape, but they disappeared by the degumming treatment. 5) The sericin of tussah silkworm (A. pernyi), showed stronger circular patterns in the meridian than the regular silkworm (Bombyx mori). 6) There was no pattern difference between Fraction A and B. 7) X-ray diffraction patterns of the Sericin 1, ll and 111 were similar except interference of 8.85A (side chain spacing). 8) The amino acids above 150 in molecular weight such as Cys. Tyr. Phe. His. and Arg. were not found quantitatively by the 60 minutes-hydrolysis (6N-HCI). 9) The X-ray Pattern of 4.6A had a tendency to disappear with hot-water, ether, and alcohol treatment. 10) The partial hydrolysis of sericin showed a cirucular interference (2A) on the meridian. 11) The sericin pellet after hydrolysis was considered to be peptides composed with specific amino acids. 12) The decomposing temperature of Sericin 111 was higher than that of Sericin I and II. 13) Thermogram of the inner portioned sericin of the cocoon shell had double endothermic peaks at 165$^{\circ}C$, and 245$^{\circ}C$, and its decomposing temperature was higher than that of other portioned sericin. 14) The infrared spectroscopic properties among sericin I, II, III and sericin extracted from each layer portion of the cocoon shell were similar. II. The characteristics of seriein swelling and solubility related with silk processing. 1) Fifteen minutes was required to dehydrate the free moisture of cocoon shells with centrifugal force controlled at 13${\times}$10$^4$ dyne/g at 3,000 R.P.M. B) It took 30 minutes for the sericin to show positive reaction with the Folin-Ciocaltue reagent at room temperature. 3) The measurable wave length of the visible radiation was 500-750m${\mu}$, and the highest absorbance was observed at the wave length of 650m${\mu}$. 4) The colorimetric analysis should be conducted at 650mu for low concentration (10$\mu\textrm{g}$/$m\ell$), and at 500m${\mu}$ for the higher concentration to obtain an exact analysis. 5) The absorbing curves of sericin and egg albumin at different wave lengths were similar, but the absorbance of the former was slightly higher than that of the latter. 6) The quantity of the sericin measured by the colorimetric analysis, turned out to be less than by the Kjeldahl method. 7) Both temperature and duration in the cocoon cooking process has much effect on the swelling and solubility of the cocoon shells, but the temperature was more influential than the duration of the treatment. 8) The factorial relation between the temperature and the duration of treatment of the cocoon cooking to check for siricin swelling and solubility showed that the treatment duration should be gradually increased to reach optimum swelling and solubility of sericin with low temperature(70$^{\circ}C$) . High temperature, however, showed more sharp increase. 9) The more increased temperature in the drying of fresh cocoons, the less the sericin swelling and solubility were obtained. 10) In a specific cooking duration, the heavier the cocoon shell is, the less the swelling and solubility were obtained. 11) It was considered that there are differences in swelling or solubility between the filaments of each cocoon layer. 12) Sericin swelling or solubility in the cocoon filament was decreased by the wax extraction.. 13) The ionic surface active agent accelerated the swelling and solubility of the sericin at the range of pH 6-7. 14) In the same conditions as above, the cation agent was absorbed into the sericin. 15) In case of the increase of Ca ang Mg in the reeling water, its pH value drifted toward the acidity. 16) A buffering action was observed between the sericin and the water hardness constituents in the reeling water. 17) The effect of calcium on the swelling and solubility of the sericin was more moderate than that of magnecium. 18) The solute of the water hardness constituents increased the electric conductivity in the reeling water.