• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.4
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• pp.371-382
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• 2022

Carbonates are inorganic ligands that are abundant in natural groundwater. They strongly influence radionuclide mobility by forming strong complexes, thereby increasing solubility and reducing soil absorption rates. We characterized the spectroscopic properties of Am(III)-carbonate species using UV-Vis absorption and time-resolved laser-induced fluorescence spectroscopy. The deconvoluted absorption spectra of aqueous Am(CO₃)₂^- and Am(CO₃)₃^3- species were identified at red-shifted positions with lower molar absorption coefficients compared to the absorption spectrum of aqua Am³⁺. The luminescence spectrum of Am(CO₃)₃^3- was red-shifted from 688 nm for Am³⁺ to 695 nm with enhanced intensity and an extended lifetime. Colloidal Am(III)-carbonate compounds exhibited absorption at approximately 506 nm but had non-luminescent properties. Slow formation of colloidal particles was monitored based on the absorption spectral changes over the sample aging time. The experimental results showed that the solubility of Am(III) in carbonate solutions was higher than the predicted values from the thermodynamic constants in OECD-NEA reviews. These results emphasize the importance of kinetic parameters as well as thermodynamic constants to predict radionuclide migration. The identified spectroscopic properties of Am(III)-carbonate species enable monitoring time-dependent species evolution in addition to determining the thermodynamics of Am(III) in carbonate systems.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.80.2-80.2
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• 2015

We present spatial and chemical distributions of Carbon-Enhanced Metal-Poor (CEMP) stars in the Milky Way's halo, as observed by the Baryon Oscillation Spectroscopic Survey (BOSS). Although the BOSS was designed to obtain spectra of galaxies and quasars, it also observed numerous metal-poor main-sequence turnoff stars for the purpose of flux calibration. The stars observed in the BOSS are two magnitudes fainter (15.5 < g < 19.2) than those in the legacy SDSS, thus it is an extremely useful sample to probe the distant halo. Using effective temperatures, surface gravities, [Fe/H], and [C/Fe] derived for these stars by the SEGUE Stellar Parameter Pipeline (SSPP), we investigate the spatial distribution of [Fe/H] and [C/Fe], the distribution of [C/Fe], and frequency of CEMP stars among these stars. These tools enable characterization of the origin of the halo and its initial mass function.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.1
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• pp.109-116
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• 2006

The heat treatment characteristics of natural talc sample was investigated in diverse analytical view point. The mass decrease comes to heat treatment was resulted by the continuous and the discontinuous process and the obtained result show very similar two step profiles with 8.9 % mass decrease. The dehydroxylation of -OH groups contained talc crystal was analyzed by spectroscopic method and the crystallographic variations was also observed after heat treatment. According to XPS result, the magnesium hydroxide($Mg(OH)_2$) of untreated talc powder changed to magnesium oxides(MgO) after heat treatment.

• Korean Journal of Optics and Photonics
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• v.3 no.2
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• pp.92-100
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• 1992

A Spectroscopic Ellipsorneter(SE) is fabricated. The PSA configuration of the rotating analyzer type where the effects of the imperfect optical elements can be minimized is adopted. The straight through operation shows that the standard deviations of tan$\psi$ and cos$\Delta$ are less than 0.2% in the spectral range of 300nm-850nm. From the film data of ellipsometric spectra the bulk dispersion relation of a few fluorides and the void distribution inside the fluoride thin films are obtained.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.397-400
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• 2003

In this study, humic and fulvic acids in soils at the vicinity of domestic atomic power plants(NPPs), located in Yungkwang(YK), Uljin(UJ), Kori(KR), Koseong(KS), Wolseong(WS) area, and in volcanic ash soils of the Cheju island(Mt. Hanla(HL), Manjanggul(MJ)) were isolated, and characterized using chemical(elemental analysis, proton exchange capacity, molecular size distribution) and spectroscopic(UV/Vis., IR, FL, $^{13}$ C NMR spectra) methods. The results were compared with one another and compiled for their DB establishments. The humic substances distribution (humic acid, fulvic acid, Humin) in the soils were also determined by IHSS standard method. Main purpose of this study was to provide a basic data needed to evaluate the effect of humic substances on the migrational behaviour of radioactive elements in contaminated surface soil.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.46-47
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• 2006

This study is about the spectroscopic characterization of abnormal cells in a macro to micro approach. In the first step a commercial UV-Vis apparatus is used, which is ultimately altered to the limits to decrease detection volume. In the ultimate stage an infrared femtosecond laser setup is used to measure on individual cells.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.250-253
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• 2009

Effective methods for monitoring the quality of polycrystalline silicon (poly-Si) films are discussed. Raman spectroscopy is typically used to determine crystallinity of poly-Si, but this method has limitations for data gathering on large substrates for mass production of poly-Si TFT backplanes. Spectroscopic ellipsometry is proposed as an alternative for fast and simple estimation of poly-Si quality on large substrates. By using both ellipsometry and Raman spectroscopy, it is possible to determine whether the quality and uniformity of the poly-Si films meet the criteria required for mass production of TFT backplanes for AMOLED panels.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.4
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• pp.483-489
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• 2007

We have investigated quantitative measurement techniques of the degree of dispersion of single-walled carbon nanotubes (SWNTs). SWNTs were suspended in aqueous media using a sodium dodecyl sulfate (SDS) surfactant. SWNTs with different dispersion states were prepared by controlling the intensity and time of sonication and centrifugation. The laser spectroscopic techniques were employed to characterize the dispersion state; i.e., raman fluorescence and absorption spectroscopic techniques. Raman spectroscopy has been used to probe the dispersion and aggregation state of SWNTs in solution. Individually suspended SWNTs show increased fluorescence peaks and decreased roping peaks at a raman shift 267 $cm^{-1}$ compared with the samples containing bundles of SWNTs. The ultraviolet-visible-near infrared (UV-vis-NIR) absorption spectrum of decanted supernatant samples show sharp van Hove singularity peaks

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.1-5
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• 2018

Wood Polymer Composites(WPC) have attracted significant attention because of ecological and environmental concerns. However, the structure of Wood Flour containing many hydroxyl groups(-OH) reduces the interface adhesion to Phenol-formaldehyde(PF) and it decreases the mechanical properties of the PF/Wood Flour Composites. The present work involves the modification of Wood Flour using silanes reinforced with Phenol-formaldehyde to enhance the mechanical properties of the composites. The spectroscopic properties of the composites were analyzed using FT-IR, XPS(X-ray Photoelectron Spectroscopy) and the mechanical properties i.e., tensile strength, flexural strength and impact strength were studied. We confirmed the modification effect of silanes by spectroscopic analysis, and the mechanical properties of the composites using wood flour modified by silanes were significantly improved.

• Journal of Life Science
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• v.5 no.4
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• pp.181-189
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• 1995

Carotenoids liberated from the red carotenoprotein from the skin of ascidian(Halocynthia roretzi)were developed on TLC, and two bands were obtained with different Rfvalues. Their chemical reactivities and spectroscopic properties were studied and elucidated as astaxanthin diester and astaxanthin monoester. After saponification of carotenoid ester, GC analysis was performed. The carotenoid ester contained oleic acid, palmitic acid and palmitoleic acids as 50% of total amount, and had higher content unsaturated fatty acid including eicosapentanoic acid than saturated fatty acid.