• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.345-346
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• 2017

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2787-2794
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• 2013

Cholesterol and cholesterol oxidation products (COPs) may accumulate in foods of animal origin during processing or storage. An effective and sensitive analytical method was developed by increasing the UV absorption of compounds through derivatization by attaching a chromophore to the functional groups of cholesterols (cholesterol, 20-hydroxycholesterol, 7-ketocholesterol, cholestane-$3{\beta}$-$5{\alpha}$-$6{\beta}$-triol, 25-hydroxycholesterol, and $5,6{\alpha}$-epoxycholesterol). The influences of the reaction time, volume of reaction solvent, amounts of derivatizing reagent, and extraction solvents were investigated, as they may influence the reaction and extraction yield. The derivatized COPs were analyzed simultaneously on a C18 column (2.1 mm i.d. ${\times}$ 100 mm length, $3.5{\mu}m$ particle size) using a gradient elution with water and acetonitrile. The derivatized COPs showed increased sensitivity and selectivity in HPLC/UV-Vis. The LOD and LOQ were in the concentration ranges of 0.018-0.55 mg/kg and 0.059-1.84 mg/kg from the powdered milk. And the accuracy and precision were 78.1-116.7% and 1.1-9.9%, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.37-46
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• 2001

In this study, We compared the properties of tinted and colored lenses with the standards m the ordinary optical properties, coloration, UV, IR and luminous transmittance, color acceptance for traffic signal, and chromaticity. The UV, lR and luminous transmittance was analysed in the range of 175 nm to 3000 nm by using a UV-Vis-IR spectrophotometer and was used in the synthesis of spectrum of various color lens. A experimental function was made from the slope obtained from the transmittance change as a function of coloration time. We could expect the ordinary optical properties and color acceptance for traffic signal of various color lenses with the requirements of US standard(ANSI Z-80.3).

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.137-140
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• 2006

This paper describes a technique combining chemometrics with UV spectroscopy for the determination of the concentra tions of two tissue additives (i.e., wet strength and softening agents) in a cellulose fiber containing solution. In single as ent solutions, the concentration of the additive can be measured by UV spectroscopy at the wavelength where the species having absorption. For a binary (i.e., containing two additives) solution system, the spectral characterization is very complicated. However, if aided by a chemometrical calibration technique, each additive in the binary solution can be quantified simultaneously. The present method is very rapid and simple, it can easily perform a continuous measurement in the changes in the additives' concentration after fiber addition, and therefore this becomes a valuable tool for the adsorption kinetics study of chemical additives onto the cellulose fibers. The time-dependent adsorption behaviors of the wet-strength, softening agent, and their both on fiber were also presented.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.350-356
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• 2014

Recently, Chemical Vapor Deposition (CVD) synthetic diamonds have been introduced to the jewelry gem market, as CVD technology has been making considerable advances. Unfortunately, CVD diamonds are not distinguishable from natural diamonds when using the conventional gemological characterization method. Therefore, we need to develop a new identification method that is non-destructive, fast, and inexpensive. In our study, we employed optical microscopy and spectroscopy techniques, including Fourier transform infra-red (FT-IR), UV-VIS-NIR, photoluminescence (PL), micro Raman, and cathodoluminescent (CL) spectroscopy, to determine the differences between a natural diamond (0.30 cts) and a CVD diamond (0.43 cts). The identification of a CVD diamond was difficult when using standard gemological techniques, UV-VIS-NIR, or micro-Raman spectroscopy. However, a CVD diamond could be identified using a FT-IR by the Type II peaks. In addition, we identified a CVD diamond conclusively with the uneven UV fluorescent local bands, additional satellite PL peaks, longer phosphorescence life time, and uneven streaks in the CL images. Our results suggest that using FT-IR combined with UV fluorescent images, PL, and CL analysis might be an appropriate method for identifying CVD diamonds.

• Conservation Science in Museum
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• v.12
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• pp.9-17
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• 2011

This study examined non-destructive UV-Vis spectrophotometry as well as 3-D fluorescence spectrophotometry of textile that made use of red dye such as Sappan wood, madder, Safflower, Gromwell. The authors produced two textile specimen that were dyed by not only two kinds of textile (cotton and silk) but also three kinds of mordanting (no-mordanting, alumen and iron), and they investigated effects of each dye material upon investigation results. At analysis with UV-Vis spectrophotometry of dyed textile specimen, dyeing made by sappan wood, madder and gromwell had significant difference depending upon mardant regardless of kinds of textile, and safflower had no significant difference depending upon textile and mordant. At analysis with 3D-fluorescence spectrophotometry, specimen dyed with sappan wood had difference with mordants, and with madder, there were difference with textiles, and safflower had inherent fluorescence spectrum regardless of textiles and mordants, while gromwell had no fluorescence spectrum.

• Analytical Science and Technology
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• v.13 no.2
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• pp.250-257
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• 2000

Paint, fiber and dye which play a critcal role in proving the relationship between a suspect and a victim or a crime scene, are one of the most frequently encountered trace evidences at a forensic laboratory, however, in usual, because of infinitesimally small sizes of forensic samples, investigation of the spectroscopic characteristics of such samples is becomming more and more prevalent in forensic science as a non-destructive method. In this study, transmittance/reflectance profiles at ultraviolet-visible region (240-780nm), were investigated by UV/visible microspectro- photometer and used to analyze the spectral characteristics of different types of 14 microfibers, 12 inks of four colors and 44 automotive paints of two colors. Good results for discrimination were given from spectra of these samples due to the characteristic bands in uv/vis region, respectively.

• Elastomers and Composites
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• v.49 no.4
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• pp.330-335
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• 2014

Niobium pentoxide ($Nb_2O_5$) nanoparticles were synthesized using niobium (V) chloride and pluronic F108NF as the precursor and templating agent, respectively. The $Nb_2O_5$-graphene nanocomposites were placed in an electric furnace at $700^{\circ}C$ and calcined under Ar atmosphere for 2 h. The morphology, crystallinity, and photocatalytic degradation activity of the samples were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and UV-vis spectroscopy. The $Nb_2O_5$-graphene nanocomposites acted as a photocatalyst in the photocatalytic degradation of organic dyes under 254 nm UV light; the organic dyes used were methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and brilliant green (BG). The photocatalytic degradation kinetics for the aforesaid dyes were determined in the presence of the $Nb_2O_5$-graphene nanocomposites.

• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.233-242
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• 2023

In recent years, energy-management studies in buildings have proven useful for energy savings. Typically, during heating and cooling, the energy from a given building is lost through its windows. Generally, to block the entry of ultraviolet (UV) and infrared (IR) rays, thin films of deposited metals or metal oxides are used, and the blocking of UV and IR rays by these thin films depends on the materials deposited on them. Therefore, by controlling the thicknesses and densities of the thin films, improving the transmittance of visible light and the blocking of heat rays such as UV and IR may be possible. Such improvements can be realized not only by changing the two-dimensional thin films but also by altering the zero-dimensional (0-D) nanostructures deposited on the films. In this study, 0-D nanoparticles were synthesized using a sol -gel procedure. The synthesized nanoparticles were deposited as deep coatings on polymer and glass substrates. Through spectral analysis in the UV-visible (vis) region, thin-film layers of deposited zinc oxide nanoparticles blocked >95 % of UV rays. For high transmittance in the visible-light region and low transmittance in the IR and UV regions, hybrid multiple layers of silica nanoparticles, zinc oxide particles, and fluorine-doped tin oxide nanoparticles were formed on glass and polymer substrates. Spectrophotometry in the UV-vis-near-IR regions revealed that the substrates prevented heat loss well. The glass and polymer substrates achieved transmittance values of 80 % in the visible-light region, 50 % to 60 % in the IR region, and 90 % in the UV region.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.177-180
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• 2000

We studied the degradation of EVA for the protection of solar cell by UV-rays irradiation. We investigated the reduction of electrical efficiency, photo transmmitance and degradation of EVA by UV-rays irradiation. We utilized the UV irradiation equiped with fluorescent 313nm UV lamp and radiated for 400 hours. For the chemial analysis, we used the UV-vis spectrometer, XPS and examined the degradation mechanism by UV irradiation. It is found that the discolored phenomena, the decrease of photo transmmitance and oxidation reaction is occured by UV irradiation on the EVA sample for the protection of solar cell.