• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.63.1-63.1
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• 2020

We investigate the effect of recent star formation (RSF) on the α-elements-to-iron ratio ([α/Fe]) estimation for galaxies. Measuring galactic [α/Fe] is a powerful tool to pinpointing the timescale of chemical evolution and star formation. Our working hypothesis is that, with increasing stellar surface temperature, absorption equivalent width (EW) of α-elements decreases faster than that of Fe-peak elements, and thus RSF will lower the line ratio of EW(α)/EW(Fe). Moreover, young stars outshine, effectively lowering EW(α)/EW(Fe) of integrated light of RSF galaxies. Here we test our hypothesis using SDSS (optical spectrophotometric), GALEX (UV photometric) and IllustrisTNG datasets, and show that, if RSF is not considered thoroughly, EW(α)/EW(Fe) lowered by RSF can be routinely misinterpreted as low [α/Fe]. We discuss possible implications of the result in the context of the conventional [α/Fe]-mass relation of galaxies.

• Economic and Environmental Geology
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• v.26 no.1
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• pp.67-81
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• 1993

This dissertation is a basic research on the degradation of rocks and aims at clarifying the relations between the progression of degree of weathering and the variation of chemical composition. The author wants to make clear the degradation of rocks and the process of formation of sedimentary rocks from a standpoint of elucidation of migration of elements. This study is considered to be significant not only as a part of research on the distribution of earth crust materials but as the petrogenesis of rocks. The chemical studies on the weathered rocks have been started relatively early and there are not a few researches on them: Goldich, 1938; Harris, et al., 1966; Ruxton, 1968; Berner, et al., 1982; Kanuss, 1983; Lasaga, 1984; Siagel, 1984. The degree of migration of elements in weathering is the composite result of various factors. Because, at the present time, it is difficult to clarify the individual and composite effects of each factor theoretically and quanititatively, we must accumulate empirical data and use them relatively. In such consideration the author acquired some data of chemical weathering from the chemical analysis of granitic and basaltic rocks in and around Fukuoka city, Japan and granitic rocks in and around Chonju and Iri cities, Korea. Because both rock types studied can be considered as representative materials of acidic and basic rocks compsing the earth crust, it is significant to examine the phenomena of weathering of both rock types. The following results are obtained from the analysis and examinations of chemical compositions of the original and weathered rocks. The loss rate of major elements has no uniformity, but the following relation holds in general; Ca, Na> K, Si> Mg> Fe, Al. As weathering proceeds, the ratio of $Al_2O_3/CaO$ shows increasing phenomena, and that of $Na_2O/CaO$ decreasing. The range of migration of composition is broad in basaltic rocks but narrow in granitic rocks. The reason is that the chemical weathering of basaltic rocks progresses more easily than that of granitic rocks. The chemical weathering potenitial index of basaltic rocks in larger than that of granitic rocks. The reason is that the chemical weathering of basaltic rocks proceeds more easily than that of granitic rocks. In weathering, the decrease of mobile cations such as $Ca^{2+}$, $Na^{2+}$, $Mg^{2+}$ and the increase of $H_2O$ in basaltic rocks are more obvious than in granitic rocks.

• Journal of Astronomy and Space Sciences
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• v.34 no.3
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• pp.199-205
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• 2017

A high resolution spectroscopic observation of the red supergiant star RM_1-390 in the Large Magellanic Cloud was made from a 3.6 m telescope at the European Southern Observatory. Spectral resolving power was R=20,000, with a signal-to-noise ratio S/N > 100. We found the atmospheric parameters of RM_1-390 to be as follows: the effective temperature $T_{eff}=4,250{\pm}50K$, the surface gravity ${\log}\;g=0.16{\pm}0.1$, the microturbulent velocity $v_{micro}=2.5km/s$, the macroturbulence velocity $v_{macro}=9km/s$ and the iron abundance $[Fe/H]=-0.73{\pm}0.11$. The abundances of 18 chemical elements from silicon to thorium in the atmosphere of RM_1-390 were found using the spectrum synthesis method. The relative deficiencies of all elements are close to that of iron. The fit of abundance pattern by the solar system distribution of r- and s-element isotopes shows the importance of the s-process. The plot of relative abundances as a function of second ionization potentials of corresponding chemical elements allows us to find a possibility of convective energy transport in the photosphere of RM_1-390.

• Economic and Environmental Geology
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• v.32 no.3
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• pp.261-271
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• 1999

Mining activity in the Gubong gold mine started in 1908 and lasted up to recent days. Heavy metals derived from the activity may be porentially toxic to human life and envirinment of this area. Because metal toxicity depends on chemical associations into five operationally defined groups: exchangeable, carbonate, reducible, oxidizable, and residual fractions, and the Most of heavy metals have significant little significance (alomost<1%). And Cu is mainly associated with the oxidizable from. Total concentration of heavy metals, pH, and mineralogy affect the chemical forms of the metals. Heavy metal concentrations. Significant amounts of metal elements (5∼65.1% in Pb, 6.2∼39.7% in Zn, 8.7∼54.7% in Cd, and 3.6∼24.7% in Cu) were present in carbonate form from mine wastes, contaminated soils and sediments. High pH value and cerussite (Pb bearing carbonate mineral) in mine wastes, contaminated soils and sediments. High pH value and cerussite (Pb beraring varbonate mineral) in mine waste support this result. Areas with high corbonate bound from would have higher potentoal conamination, however, because elements of carbonate bound forms are easily mobilized under lower pH conditions in the surface envionments due to acid to rain soil acidification.

• Carbon letters
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• v.9 no.2
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• pp.131-136
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• 2008

In order to investigate the effect of doping C, N, B and F elements on $TiO_2$ for reducing the band gap, the heat treatment of $TiO_2$ was carried out with tetraethylammonium tetrafluoroborate. Through XRD and XPS analysis, the C, N, B and F doped anatase $TiO_2$ was confirmed. According to the increase of temperature during treatment, the particle size was increased due to aggregation of $TiO_2$ with elements (B, C, N and F). To investigate the capacity of photocatalyst for degradation of dye under solar light, the degradation of acridine orange and methylene blue was conducted. The degradation of dyes was carried out successfully under solar light indicating the effect of doping elements (B, C, N and F) on $TiO_2$ for reducing the band gap effectively.

• The Korea Journal of Herbology
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• v.20 no.2
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• pp.17-26
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• 2005

Objectives : The study has been undertaken to scrutinize the results of Halloysitum Rubrum before and after physical and chemical manipulation. Methods : I used X-rays diffracted analysis system(Phillips X'Pert - MPD System) on condition of 40Kv, Anode of Cu Ka to grasp the compositions of crude Halloysitum Rubrums which have been from here and there after pulverization them below 200 mesh. X-rays fluorescence analysis system have been used to check the chief elements content of the ore on condition of 40Kv, 95mA. ICP-MS analysis system(Perkin Elmer, Elan 6100)have been used after a micro-elements and a heavy metals take advantage of mixed acid were dissolved completely. Results : The compositions of the ore Halloysitum Rubrum are composed of large amount of Halloysite and Kaolinite, and small amount of Hematite, Alum, quartzite. The chief elements content of the ore Halloysitum Rubrum are composed of Al and Si. A heavy metals in Halloysitum Rubrum are As, Cd, Cr, Cu, Pb, Zn, etc. As and Zn's amounts was lessen after physical and chemical manipulation Halloysitum Rubrum are decreased at $400^{\circ}C\;and\;450-500^{\circ}C$ each by heat analysis system. Conclusion : Results of this study show that Halloysitum Rubrum can be used in a diverse ways to treat many kinds of disease.

• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.383-390
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• 2002

To investigate behaviors of Ti and O elements and microstructures of anodic titanium oxide films, the films were prepared by anodizing pure titanium in $H_2$S $O_4$, $H_3$P $O_4$, and $H_2O$$_2$ mixed solution at 180V. The microstructures and chemical states of the elements were analyzed using SEM, X-ray mapping, AFM, XRD, XPS (depth profile). The films formed on a titanium substrate showed porous layers which were composed of pore and wall, And with increasing anodizing time a hexagonal shape of cell structures were dominant and solace roughness increased. From the XRD result the structure of the Ti $O_2$ layer was anatase type of crystal on the whole. In the XPS spectra it was found that Ti and O were chemically binded in forms of Ti $O_2$, TiOH, $Ti_2$ $O_3$ at Ti 2p, and Ti $O_2$, $Ti_2$ $O_3$, $P_2$ $O_{5}$, S $O_4^{2-}$ at O ls respectively. Concentration of Ti $O_2$ decreased as the depth increased from the surface of the oxide film towards the substrate, but to the contrary concentrations of TiOH and $Ti_2$ $O_3$ increased.d.

• Economic and Environmental Geology
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• v.7 no.4
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• pp.175-184
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• 1974

Weathering of granites has a great geochemical significance, because of their chemical stability near the earth surface which is more pronounced than in most other rocks. The author intended to observe the relative mobility of major elements in weathering process of the granite, distributed on outskirts of Iri city Jeolla-bugdo, Korea. He analysed fresh granites and weathered ones from the Baeg-Gu granite mass and obtained following conclusions in the triangle-diagrams and the oxidized variation diagrams of the samples. 1) The increasing phenomena of $H_2O$ was observed clearly in early and late stages of weathering process. 2) The early stage of weathering is commenced by physical weathering and followed by chemical weathering. 3) The ratio of $FeO/Fe_2O_3$, FeO/MgO, and $SiO_2/Al_2O_3$ decreased uniformly from early to late stage of weathering processes. 4) It was proved that weathering potential of granite was larger than that of basaltic rock. 5) The order of mobility in major elements was Ca, Na and K

• Proceedings of the KSEEG Conference
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• 2005.04a
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• pp.3-6
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.303-305
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• 2011

A study of different levels of Nutrition Elements and the chemical properties of the soil was conducted to determine the yield performance of potato. Application of sulfur, potassium, and Magnesium significantly affected final height, dry matter content, and crispiness of potato. The final pH, organo-nitrogen, phosphorus, potassium, and magnesium content in the soil were significantly affected by S-K-Mg application.