• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.5
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• pp.30-36
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• 2013

Hydrophobic property of Kapok fiber was investigated by sequential removal of its components by different extraction methods. Acetone extraction for the removal of the hydrophobic extractives, holo-cel-lulose preparation after the removal of lignin and xylan extraction by potassium hydroxide was applied. The degree of hydrophobicity of each samples were measured by the water sorption ability. The water sorption ability of Kapok fiber was increased by the sequential treatment of acetone extraction, holocellulose preparation and xylan removal. Based on holocellulose compositional analysis by $^1H$-NMR spectroscopic method, the unusual high amount of the acetyl groups in the holocellulose of Kapok partially contributed to the hydrophobicity of Kapok holocellulose fiber.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1276-1276
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• 2001

Polycyclic aromatic hydrocarbons(PAHs) are widely distributed in the environment and are often implicated as potential carcinogens. The chromatographic methods of detection and quantitative determination of PAHs in environmental samples are costly, time consuming, and do not account for all kinds of PAHs. This work describes a quantitative spectroscopic method for the analysis of mixtures of eight PAHs using multivariate calibration models for Fourier transform near infrared(FT-NIR) spectral data. The NIR spectra of mixtures of PAHs (anthracene, pyrene, 1,2-benzanthracene, perylene, chrysene, benzo(a)pyrene, 1-methylanthracene and benzo(ghi)perylene) were measured in the wavelength range from 1100 nm to 2500 nm. The spectral data were processed using a partial least squares regression. We have studied the spectral characteristics of NIR spectra of mixtures of PAHs. It was possible to determine each PAM used in this study at the environmental level(mg L-1) in the laboratory samples. Further development may lead to the rapid determination of more PAHs in typical environmental samples.

• Journal of Pharmaceutical Investigation
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• v.23 no.2
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• pp.61-69
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• 1993

Prodrug of cefazolin (CFZ) was prepared with the objective of improving its oral bioavailability. Cefazolin phthalidyl ester (CFZ-PT) was synthesized and evaluated as potential prodrug form. The successful synthesis of CFZ-PT was identified by spectroscopic analysis. Partition coefficient studies showed that CFZ-PT is more lipophilic than CFZ and the ester was hydrolyzed enzymatically into the parent drug in blood, liver and intestinal homogenates. The pharmacokinetic characteristics of CFZ-PT and CFZ were compared following oral administrations to rabbits. Serum CFZ concentration was determined by HPLC method and the ester compound (prodrug) was not detected in serum following oral administration of CFZ-PT. CFZ-PT did not have antimicrobial activity in vitro against Bacillus subtilis ATCC 6633, whereas CFZ-PT in serum after oral administration to rabbits had antimicrobial activity. From above observations, it was noted that CFZ-PT is rapidly hydrolyzed to CFZ in the body and the bioavailability of CFZ-PT was increased by 3.5-fold than that of CFZ. From these results of this study, it was concluded that CFZ-PT may be a novel prodrug of CFZ which can improve the oral absorption of CFZ.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.832-834
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• 1992

Using the PECVD method, the silicon nitride films were deposited by changing the $SiH_4/NH_3$ gas flow ratio from 0.2 to 1.4 at an interval of 0.2, AES, FTIR, and Spectroscopic Ellipsomter were used to analyze the film composition and structure, the refractive index, and the deposition rate. Also the C-V analysis was used to estimate the memory performance in the capacitor type MNOS memory devices, which utilized native oxide as the tunneling barrier, with the silicon nitride by the above deposition conditions. As a result, it was confirmed that the performance of MNOS memory devices with PECVD silicon nitride was comparable to that with LPCVD or APCVD silion nitride.

• Korean Journal of Pharmacognosy
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• v.45 no.1
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• pp.88-92
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• 2014

Lysimachia foenum-graecum (LF) has been used for home remedy of common cold and headache in China. Foenumoside B from LF has been reported for anti-obesity effects. We used foenumoside B as a marker for content evaluation of different parts of LF. Ethanol extract of LF was used for isolation of foenumoside B and purified further by column chromatography. The structure was identified as foenumoside B by interpretation of spectroscopic analysis, including $^1H$-, $^{13}C$-NMR and FT-ICR-MS. High-performance liquid chromatography (HPLC) method was used to compare the quantitative level of foenumoside B in different parts of LF. Foenumoside B contents in the leaf, stem, and aerial part showed significant differences. Contents of foenumoside B was detected highly in the leaf extracts. The results would be useful for efficient extraction of foenumoside B in LF.

• Natural Product Sciences
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• v.26 no.3
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• pp.236-243
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• 2020

Salvia plebeia R. Br. is a plant which has been used as an edible crop and traditional medicine in Asian countries. In this study, HPLC-PDA analysis and countercurrent chromatography (CCC) coupled with reversed-phase (RP) HPLC method were applied to isolate ten isolates from 3.3 g of n-butanol soluble extract from hot-water extract of S. plebeia. The use of CCC enabled us to efficiently fractionate the starting material with less sample loss and facilitate the isolation of compounds from S. plebeia extract using RP-HPLC. The isolates were determined to be caffeic acid (1), 6-hydroxyluteolin 7-O-β-D-glucoside (2), eudebeiolide B (3), (R)-rosmarinic acid (4), homoplantaginin (5), eudebeiolide D (6), plebeiolide C (7), salpleflavone (8), eupafolin (9) and hispidulin (10) based on the spectroscopic evidence.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.1
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• pp.91-95
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• 1999

The Streptomyces albulus broth, when the polylysine in the broth, that has powerful growth inhibiting effect far many microbes, is its maximum, had filtered off the cells, to use the broth as preservative for keeping favorable taste of Korean Kimchi. Some microorganisms in their specific growth medium, known to deteriorate the useful nutrient of the Kimchi, has grown with different amounts of the inhibiting broth, to determine the minimum growth inhibition concentration. The ${\varepsilon}$-poly-L-lysine had been identified from the IR spectroscopic analysis of the purified poly lysine of the broth from ion exchange chromatographic separation. The content of the polylysine had been determined by methyl orange decoloration effect. Though the minimum inhibition concentration, evaluated by the naked eye based on the conventional method measuring the turbid feature after 18 hours of culture, has different values each other, the observed effects confirmed that the crude broth could be used as a natural preservative for the Kimchi in extending the fair taste.

• Journal of The Korean Astronomical Society
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• v.26 no.2
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• pp.115-134
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• 1993

The light curve and radial velocity curve of multiperiodic dwarf cepheid VI719 Cyg (HD200925) with peculiar light curve have been reanalyzed in order to identify the oscillation modes to confirm the helium settling within the envelope. To do these, through the period search for the photometric and radial velocity data from the literature, two different periods were determined and the oscillation modes corresponding to the first and second periods were identified as the fundamental and first radial overtones. Hence the helium settling within the envelope was confirmed from the period ratio. The color excess, metallicity, effective temperature, and surface gravity corresponding to two different modes were determined and it was found that these parameters almost do not depend upon different oscillation mode. By utilizing the surface brightness method, we investigated the variation of angular diameter and radial displacement and it was found that the angular variation is very peculiar. Also by referring to the stellar models, mass and age were determined as $2.7M_{\bigodot}$ and 0.42 Gyr respectively which make this variable star heavier and younger than other multimode dwarf cepheids. Preliminary spectroscopic CCD observations were carried out and it was found that Mg in VI719 Cygni is nearly solar abundent according to the analysis of $5172.68{\AA}MgI$ line which is inconsistent with the photometric result. It was suggested that VI719 Cyg may be classified as a $\rho$ Pup stars according to the photometric characteristics.

• Carbon letters
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• v.10 no.4
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• pp.314-319
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• 2009

The surface treatment effects of reinforcement filler were investigated based on the dynamic mechanical properties of mutiwalled carbon nanotubes (MWCNTs)/epoxy composites. The as-received MWCNTs(R-MWCNTs) were chemically modified by direct oxyfluorination method to improve the dispersibility and adhesiveness with epoxy resins in composite system. In order to investigate the induced functional groups on MWCNTs during oxyfluorination, X-ray photoelectron spectroscopy was used. The thermo-mechanical property of MWCNTs/epoxy composite was also measured based on effects of oxyfluorination treatment of MWCNTs. The storage modulus of MWCNTs/epoxy composite was enhanced about 1.27 times through oxyfluorination of MWCNTs fillers at $25^{\circ}C$. The storage modulus of oxyfluorinated MWCNTs (OF73-MWCNTs) reinforced epoxy composite was much higher than that of R-MWCNTs/epoxy composite. It revealed that oxygen content led to the efficient carbon-fluorine covalent bonding during oxyfluorination. These functional groups on surface modified MWCNTs induced by oxyfluorination strikingly made an important role for the reinforced epoxy composite.

• Membrane Journal
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• v.23 no.2
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• pp.136-143
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• 2013

Recently, a novel coating method using an aqueous doapmine solution was proposed, the deposited coating was found to have extraordinarily strong-adhesion to numerous materials such as metal and polymers. However, it has suffered from many controversy in scientific fields due to its final structure and deposited mechanisms. Here, we have proposed a new structure for final dopamine product coupling with solid state spectroscopic, thermal behavior, and gas transport behaviors of dopamine coated microporous polyethersulfone membranes. In its final analysis, the results represented that it is a supramolecular aggregated of monomers consisting of 5,6-dihydroxyindoline and its derivative in contrast to previously proposed polymeric structure.