• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.29-36
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• 2010

The spectroscopic characteristics of synthetic and natural emeralds were investigated by UV-Vis and FTIR spectroscopy before and after heat treatment. The Mo and Co for synthetic flux and C1 for synthetic hydrothermal emeralds have been detected by X-ray fluorescence analysis. In the region of UV-Visible, the absorption of emerald from Colombia was generally increased after the heat treatment. The peak which related to C1 component in the $3000-2600cm^{-1}$ was shown in the hydrothermal synthetic emeralds by FTIR spectroscopy. The $2358cm^{-1}$ peak which originates from $CO_2$ was decreased after the heat treatment in the natural emerald. This was corresponded with the changes of gas element after heat treatment.

• Journal of the Korean Chemical Society
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• v.65 no.4
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• pp.254-259
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• 2021

The purpose of this work is the development of a method for an effective, less expensive, rapid, and simultaneous determination of three phenolic compounds (caffeic acid, gallic acid, and quercetin) widely present in food resources and known for their antioxidant powers. The method relies on partial least squares (PLS) calibration of UV-visible spectroscopic data. This model was applied to simultaneously determine, the concentrations of caffeic acid (CA), gallic acid (GA), and quercetin (Q) in six herb infusion extracts: basil, chive, laurel, mint, parsley, and thyme. A wavelength range (250-400) nm, and an experimental calibration matrix with 21 samples of ternary mixtures composed of CA (6.0-21.0 mg/L), GA (10.0-35.2 mg/L), and Q (6.4-17.5 mg/L) were chosen. Spectroscopic data were mean-centered before calibration. Two latent variables were determined using the contiguous block cross-validation procedure after calculating the root mean square error cross-validation RMSECV. Other statistic parameters: RMSEP, R², and Recovery (%) were used to determine the predictive ability of the model. The results obtained demonstrated that UV-visible spectrometry and PLS regression were successfully applied to simultaneously quantify the three phenolic compounds in synthetic ternary mixtures. Moreover, the concentrations of CA, GA and Q in herb infusion extracts were easily predicted and found to be 3.918-18.055, 9.014-23.825, and 9.040-13.350 mg/g of dry sample, respectively.

• Journal of The Korean Astronomical Society
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• v.33 no.1
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• pp.57-73
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• 2000

We have done a spectroscopic study of the solar transition region using high resolution UV & EUV data obtained by SUMER(Solar Ultraviolet Measurements of Emitted Radiation) on board SOHO(Solar and Heliospheric Observatory). Optically thin and conspicuous emission lines observed at the solar limb are carefully selected to acquire average values of physical parameters for the quiet region as a function of radial distance. Our main results found from the present study can be summarized as follows. 1) Nonthermal velocities estimated from various UV lines do not decrease with height at least within one total line intensity scale height above the limb. 2) Nonthermal velocity distribution with temperature is very similar to that of the disk center, in the sense that its peak is located around $2{\times}10^5 K$, but the value is systematically larger than that of the disk. 3) It is found that nonthermal velocity is inversely proportional. to quadratic root of electron density up to about 10 arc seconds above the limb, i.e. ${\xi}\~N_e^{-1/4}$, implying that the observed nonthermal broadening can be attributed to Alfven waves passing through the medium. 41 Electron density estimated from the O V 629/760 line ratio is found to range from about $1{\times}10^{10}cm^{-3}$ to $2{\times} 10^{12}cm^{-3}$ in the transition region.

• 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.

• Natural Product Sciences
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• v.24 no.1
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• pp.36-39
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• 2018

Phytochemical analysis of Boehmeria nivea (Bn) leaves by medium pressure liquid chromatography led to the isolation of a flavonoid glycoside identified by spectroscopic analysis as rutin. The amount of rutin in the leaves of Bn harvested from nine regions in South Korea (Bn 1-9) which were collected on the months of June, July, August, and September was determined by HPLC-UV analysis. A gradient elution program that utilizes a $Discovery^{(R)}$ C18 ($4.6{\times}250mm$, $5{\mu}m$) column and mobile phase composed of 1% acetic acid-water: acetonitrile (90:10 to 60:40 for min) was followed. The injection volume and flow rate were $10{\mu}l$ and 1 mL/ min, respectively. UV detection was set at 350 nm. Results show that Bn-8 harvested in September reported the highest content of rutin among the samples analyzed. This study provides a basis for the optimal harvest time of Bn which maximizes the yield of rutin.

• 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.

• Archives of Pharmacal Research
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• v.4 no.1
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• pp.43-51
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• 1981

The effect of some alcohols on the riboflavin derivatives in non-polar solvent was studied by various spectroscopic method in order to support the view point that alcohol may directly interect with the isoalloxazine moiety of FAD, the coenzyme of D-amino-acid oxidase. The most possible association complex between alcohol and riboflavin is the 1:1 complex through the 2-C carbonyl function of the isollaxazine ring nd the hydroxyl proton of alcohol. It is appeared that methanol has a larger association constant than any other alcohols, and the association constant decreases with the carbon number increases and being bulkier in the alkyl group of alcohols.

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.353-356
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• 2010

Zinc oxide (ZnO) thin films were deposited using atomic layer deposition. The electrical and optical properties were characterized using Hall measurements, spectroscopic ellipsometry and UV-visible spectrophotometry. The electronic concentration and the mobility were found to be critically dependent on the deposition temperature, exhibiting increased resistivity and reduced electronic mobility at low temperature. The corresponding optical properties were measured as a function of photon energy ranging from 1.5 to 5.0 eV. The simulated extinction coefficients allowed the determination of optical band gaps, i.e., ranging from 3.36 to 3.41 eV. The electronic carrier concentration appears to be related to the reduction in the corresponding band gap in ZnO thin films.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.143-144
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• 1998

The spectroscopic characteristic of 9 items in the urinalysis strip are measured to develop the urine analysis system. From experimental results, we determined the wavelength range which could accurately distinguish the degrees of 9 test items. Simulation is performed to distinguish the primary color reaction in the urinalysis strips using reflectance of urine strips, luminous intensity of LEDs, and spectral sensitivity of photodiodes. The simulation results agree well with experimental results by using UV-Visible spectrophotometer.

• Natural Product Sciences
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• v.21 no.4
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• pp.273-277
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• 2015

Comprehensive chemical analysis of extracts and fractions of marine actinomycete strains led to the discovery of a new minor secondary metabolite, salternamide E (1), from a saltern-derived halophilic Streptomyces strain. The planar structure of salternamide E (1) was elucidated by a combinational analysis of spectroscopic data including NMR, MS, UV, and IR. The absolute configuration of salternamide E (1) was determined by circular dichroism spectroscopic analysis. Salternamide E displayed weak cytotoxicity against various human carcinoma cell lines.