• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.83-86
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• 1989

Electrical conductivity, I - V and DLTS have been measured on polycrystalline samples of $\alpha-Fe_{2}O_{3}$ containing small deviation from stoichiometry and small amounts of added titanium. DLTS (Deep Level Transient Spectroscopy) in the current transient mode has been applied to the measurement of the trap density at the grain boundary. Titanium enters the $\alpha-Fe_{2}O_{3}$ lattice substitutionally as $Ti^{4+}$, thus producing an $Fe^{2+}$ and maintaining the average charge per cation at three. The $Fe^{2+}$acts as a donor center with respect to the surrounding $Fe^{3+}$ions.

• Archives of Pharmacal Research
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• v.28 no.9
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• pp.1031-1036
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• 2005

[ $(+)-Lyoniresinol-3{\alpha}-O-\beta-D-glucopyranoside$ ] (1) was isolated from an ethyl acetate extract of the root bark from Lycium chinense Miller, and its structure was determined using 1D and 2D NMR spectroscopy including DEPT, HMQC, and HMBC. $(+)-Lyoniresinol-3{\alpha}-O-\beta-D-glucopyranoside$ exhibited potent antimicrobial activity against antibiotic-resistant bacterial strains, methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients, and human pathogenic fungi without having any hemolytic effect on human erythrocytes. In particular, compound 1 induced the accumulation of intracellular trehalose on C. albicans as stress response to the drug, and disrupted the dimorphic transition that forms pseudo-hyphae caused by the pathogenesis. This indicates that $(+)-Lyoniresinol-3{\alpha}-O-\beta-D-glucopyranoside$ has excellent potential as a lead compound for the development of antibiotic agents.

• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.247-251
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• 1985

Dichloro cobalt(III) complex of a flexible tetradentate ligand of ethylenediamine-N,N'-di-S-${\alpha}$-propionic acid (eddp) has been prepared via the air-oxidation technique. Only ${\Delta}$-cis isomer has been yielded showing high stereoselectivity of the eddp ligand. Elemental analysis, ir, nmr and electronic absorption spectra have been used to characterize the complex and the absolute configuration of the complex is assigned by means of the nmr spectroscopy.

• Korean Journal of Microbiology
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• v.23 no.4
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• pp.302-308
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• 1985

It is shown by means of nuclear magnetic resonance spectroscopy that 3,4,5-trihydroxy-2-keto-L-valeraldehyde (L-xylosone), an ${\alpha}$-ketoaldehyde, is formed during the oxidative catabolism of L-ascorbic acid. It is proposed that this substance serves as a substrate for the glyoxalase system by which it is transformed to L-xylonic acid. As L-xylonic acid is further oxidized to L-erythroascorbic acid, a biochemical pathway is proposed for the action of vitamin C which consists of two further ${\gamma}$-lactones and three different substrates of the glyoxalase system.

• Bulletin of the Korean Chemical Society
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• v.4 no.1
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• pp.45-47
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• 1983

In order to standardize the ${\sigma}^*,\;{\rho}^*$ is taken as unity for the benzoic acids by analogy with the fact that ${\rho}$ of benzoic acids in the ground state is taken as unity. The $pK_{\alpha}^*$ of many benzoic acid derivatives are determined by UV spectroscopy and fluorescence spectral analysis whenever possible. The ${\sigma}^*$ constants are derived from the Hammett equation utilizing these $pK_{\alpha}^*$ values and the $pK_{\alpha}^*$ of the benozic acid derivatives showed better correlationship with ${\sigma}^*$ than ${\sigma},\;{\sigma}^+\;and\;{\sigma}^-$ as expected. From these ${\sigma}^*$ values, ${\rho}^*$ of the phenol derivatives was calculated to be 1.28. The new standardized ${\sigma}^*$ values are calculated from the $pK_{\alpha}^*$ values of phenols since more accurate and abundant data are available for phenols than the benzoic acid derivatives.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.812-818
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• 2011

[ $V_{0.9}Sb_{0.1}O_x$ ]systems, bulk and deposited on different supports (five types of ${\gamma}$-aluminas, ${\alpha}$-alumina, silica-alumina, silica gel, magnesium oxide), have been tested in the oxidative dehydrogenation (ODH) of iso-butane. This statement is derived from the data obtained by a set of characterisation techniques(specific surface area measurements, X-ray diffraction, X-ray photoelectron spectroscopy, laser Raman spectroscopy, in situ differential scanning calorimetry and in situ diffuse reflectance-absorption infrared Fourier transform spectroscopy).

• Journal of the Korean Magnetics Society
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• v.13 no.1
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• pp.21-28
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• 2003

M-type hexagonal BaF $e_{12-2x}$ $Co_{x}$ $Ti_{x}$ $O_{19}$ (0$\leq$x$\leq$1.0) ferrite powders prepared by a sol-gel method. The crystallographic and magnetic properties were characterized with a x-ray diffraction (XRD), thermogravimetry (TG), differential thermal analysis (DIA), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), and Mossbauer spectroscopy. The result of XRD measurements show that the a and c lattice parameters increase with increasing x from $\alpha$=5.882 and c=23.215 $\AA$ for $\chi$=0.0, to $\alpha$=5.895 and c=23.295 $\AA$ for $\chi$=1.0. From the Mossbauer results, the $Co^{2+}$- $Ti^{4+}$ site occupancies have been affected the changes in the magnetization and in the coercivity. The Curie temperature linearly decreases with increasing $Co^{2+}$- $Ti^{4+}$ concentration x.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.881-885
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• 2017

This work presents a new technique for discriminating between alpha particles of different energy levels. In a first study, two groups of alpha particles emitted from radium-226 and americium-241 sources were successfully separated using a CR-39 microfilm of appropriate thickness. This thickness was adjusted by chemical etching before and after irradiation so that lower-energy particles were stopped within the detector, while higher-energy particles were revealed on the back side of the detector. The number of tracks on the front side of the microfilm represented all alpha particles incident on that side from the two sources. However, the number of tracks on the back side of the microfilm represented only the long-range alpha particles of higher energy that arrived at that side. Therefore, by subtracting the number of tracks on the back side from the number of tracks on the front side, one could easily determine the number of tracks for the short-range alpha particles of lower energy that remained embedded in the microfilm. Discrimination of the two energy levels is thus achieved in a simple, fast, and reliable process.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1159-1165
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• 2016

The nutritional value of feed proteins and their utilization by livestock are related not only to the chemical composition but also to the structure of feed proteins, but few studies thus far have investigated the relationship between the structure of feed proteins and their solubility as well as digestibility in monogastric animals. To address this question we analyzed soybean meal, fish meal, corn distiller's dried grains with solubles, corn gluten meal, and feather meal by Fourier transform infrared (FTIR) spectroscopy to determine the protein molecular spectral band characteristics for amides I and II as well as ${\alpha}$-helices and ${\beta}$-sheets and their ratios. Protein solubility and in vitro digestibility were measured with the Kjeldahl method using 0.2% KOH solution and the pepsin-pancreatin two-step enzymatic method, respectively. We found that all measured spectral band intensities (height and area) of feed proteins were correlated with their the in vitro digestibility and solubility ($p{\leq}0.003$); moreover, the relatively quantitative amounts of ${\alpha}$-helices, random coils, and ${\alpha}$-helix to ${\beta}$-sheet ratio in protein secondary structures were positively correlated with protein in vitro digestibility and solubility ($p{\leq}0.004$). On the other hand, the percentage of ${\beta}$-sheet structures was negatively correlated with protein in vitro digestibility (p<0.001) and solubility (p = 0.002). These results demonstrate that the molecular structure characteristics of feed proteins are closely related to their in vitro digestibility at 28 h and solubility. Furthermore, the ${\alpha}$-helix-to-${\beta}$-sheet ratio can be used to predict the nutritional value of feed proteins.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.12-18
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• 1992

The trap levels of ZnO-based varistor are obtained by Isothermal Capacitance Transient Spectroscopy method. Here ICTS measuring system consists of YHP 4192A Impedance Analyzer and a personal computer for the data acquisition. Between $-40^{\circ}C$ and $60^{\circ}C$, the grain boundary trap levels of 0.48 and 0.94eV were detected for $ZnO-Bi_2O_3-MnO$ system. The hole omission spectra are observed in the case of the addition of CoO into the $ZnO-Bi_2O_3$ system, while the electron emission spectra are detected in the case of the addition of MnO. The nonlinear resistance coefficient $\alpha$ increases with the decrease of the dormer concentration. Finally, the trap level density of $ZnO-Bi_2O_3-MnO$ system is found to decrease with the amount of CoO, while $\alpha$ is found to increase with the amount of CoO.