• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.4
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• pp.138-141
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• 2001

The fluorescence emission spectrum of Cr$^{3+}$ doped BeAl$_{6}$ O$_{10}$ crystals at 300 K contains a broad band, three R-like lines and another emission lines. It has been identified by a lifetime resolution spectroscopic technique that there are three kinds of single-Cr$^{3+}$ centers, Cr(I), Cr(II), Cr(III), in this crystal. Cr(I) and Cr(II) are high-crystal field centers responsible for the three main "R-lines", and Cr(III) is a low-crystal field center responsible for the main broad band emission. The structures of these luminescent centers are reported.ted.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.812-816
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• 2003

Accurate ab initio computational chemistry has evolved dramatically. In particular, the development of multireference-based approaches has opened up a completely new area, and has had a profound impact on the potential of theoretical chemistry. Multireference-based perturbation theory (MRPT) is an extension of the closed-shell single reference Møller-Plesset method, and has been successfully applied to many chemical and spectroscopic problems. MRPT has established itself as an efficient technique for treating nondynamical and dynamical correlations. Usually, a complete active space self-consistent field (CASSCF) wave function is chosen as a reference function of MRPT. However, CASSCF often generates too many configurations, and the size of the active space can outgrow the capacity of the present technology. Many attempts have been proposed to reduce the dimension of CASSCF and to widen the range of applications of MRPT. This review focuses on our recent development in MRPT.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.47-49
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• 1995

We report the spectroscopic properties of column-III nitrifies of GaN, GaInN, and AlGaN. The column-III nitride semiconductors are promising materials to realize the current-injection-type blue-and ultraviolet (UV)-light-emitting devices with high performance. To acheive the lasing with low threshold, the devices are must constructed to double heterostructure by succesive epitaxial growth technique, and we must confine the carriers in the potential barrier and optical confinement in wave guide between barrier and active layers has different refractive index. The refractive index of column-III nitride semiconductors, however, are rarely reported. The measured refractive index was 2.9, and the observed characteristic peak near the enrgy gap was analysed using a dielectric function and may due to excitonic contribution.

• Journal of the Korean Society for Nondestructive Testing
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• v.12 no.1
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• pp.9-15
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• 1992

Ultrasonic spectroscopy is likely to become a very powerful NDE method for detection of microfects and thickness measurement of thin film below the limit of ultrasonic distance resolution in the opaque materials, provides a useful information that cannot be obtained by a conventional ultrasonic measuring system. In this paper, we considered a thin film below the limit of ultrasonic distance resolution sandwitched between two substances as acoustical analysis model, demonstrated the usefulness of ultrasonic spectroscopic analysis technique using information of ultrasonic frequency for measurements of thin film thickness, regardless of interference phenomenon and phase reversion of ultrasonic waveform. By using frequency intervals(${\triangle}f$) of periodic minima from the ratio of reference power spectrum of reflective waveform obtained a sample to power spectrum of multiple reflective waves obtained interference phenomenon caused by ultrasonic waves reflected at the upper and lower surfaces of a thin layer, can measured even dimensions of interest are smaller than the ultrasonic wave length with simplicity and accuracy.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.309-311
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• 2017

Properties of ULIRGs (Ultra Luminous InfraRed Galaxies) are important to understand the cosmic star formation history. To investigate their properties up to z=0.3, we search for ULIRGs identified by using the AKARI/FIS Bright Source Catalogue and the WISE All-Sky catalog. By matching the AKARI $90{\mu}m$ catalogue with the WISE catalog, we selected 3,452 galaxies. Additionally, combined with the SDSS DR10 spectroscopic data, we selected 952 galaxies with spec-z. We then computed total infrared luminosities using SED fitting technique, and identified 31 ULIRGs, 561 LIRGs and 344 IRGs. For these galaxies, we found an indication that ULIRGs selected by AKARI change the SED shape with redshift (z = 0.1 - 0.3).

• Journal of Biosystems Engineering
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• v.23 no.1
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• pp.49-56
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• 1998

The objectives of this study were to develop models to predict the contents of moisture and protein of single kernel of brown rice based on visible/NIR (near-infrared) spectroscopic technique. The reflectance spectra of rice were obtained in the range of the wavelength 400 to 2,500 nm with 2 nm intervals. Multiple linear regression(MLR) and partial least squares (PLS) were used to develop the models. The MLR model using the first derivative spectra(10 nm of gap) with Standard Normal Variate and Detrending (SNV and Drt.) preprocessing showed the best results to predict moisture content of the sin린e kernel brown rice. To predict the protein content of a single kernel of brown ricer the PLS model used the raw spectra with multiplicative scatter correction(MSC) preprocessing over the wavelength of 1,100~1,500 nm.

• Near Infrared Analysis
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• v.1 no.1
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• pp.23-26
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• 2000

The objectives of this study were to examine the ability to predict soluble solid and firmness in intact apple based on the visible/near-infrared spectroscopic technique. Two cultivars of apples, Delicious and Gala, were handled, tested and analyzed. Reflectance spectra, Magness-Taylor (MT) Firmness, and soluble solids in apples were measured sequentially. Maximum and minimum diameters, height, and weight of apples were recorded before the MT firmness tests. Apple samples were divided in to a calibration set and a validation set. The method of partial least squares (PLS) analysis was used. a unique set of PLS loading vectors (factors) was development for soluble solid and firmness. The PLS model showed good relationship between predicted and measured soluble solids in intact apples in the wavelength range of 860∼1078 nm. However, the PLS analysis was not good enough to predict the apple firmness.

• Korean Journal of Pharmacognosy
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• v.38 no.4
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• pp.354-357
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• 2007

Three compounds (1-3) were isolated from the roots of Potentilla discolor (Rosaceae). The structure of compounds 1-3 were elucidated as stigmast-5-en-3-ol $({\beta}-sitosterol,\;1),\;2,19{\alpha}-dihydroxy$-2-oxo-urs-1,12-dien-28-oic acid (fupenjic acid, 2), 3-O-${\beta}$-D-glucopyranosylstigmast-5-en-3-ol (${\beta}-sitosterol\;{\beta}-D-glucopyranoside, 3) based on physical and spectroscopic data. $^{13}C-NMR$ assignments were completed by 2D-NMR technique. The three compounds were firstly isolated from Potentilla discolor.

• Journal of Radiation Protection and Research
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• v.45 no.1
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• pp.11-15
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• 2020

Background: There have been various studies to investigate the mechanisms of DNA damage from low-energy electrons. To understand the mechanism of these strand breaks, it is necessary to investigate the dissociation mechanism of the DNA constituents, that is, bases, sugars, and phosphates. Materials and Methods: We studied the dissociation of thymine base upon interaction with low-energy electrons. For this experiment, thymine powder was pressed onto the indium base and irradiated by 5 eV electrons. Results and Discussion: Non-irradiated and irradiated thymine samples were compared and analyzed using the X-ray photoelectron spectroscopic technique to analyze the dissociation patterns of the molecular bonds after low-energy electron irradiation of thymine. Conclusion: With 5 eV electron irradiation, C-C and N-C = O bonds are the primary dissociations that occur in thymine molecules.

• Journal of the Korean Ceramic Society
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• v.52 no.6
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• pp.502-507
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• 2015

We examined the photo catalytic activity and catalytic recyclability of CdSe/graphene nanocomposites fabricated via modified hydrothermal technique. The prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Raman spectroscopic analysis, and X-ray photoelectron spectroscopy (XPS). The photocatalytic behavior was investigated through decomposition of RBB as a standard dye under visible light radiation. Our results indicate that there is significant potential for graphene based semiconductor hybrids materials to be used as photocatalysts under visible light irradiation for the degradation of organic dyes from industry effluents.