• Bulletin of the Korean Chemical Society
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• v.27 no.12
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• pp.2040-2044
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• 2006

Dielectric studies of methyl acrylate with 1-propanol, 1-butanol, 1-heptanol and 1-octanol binary mixtures have been carried out over the frequency range from 10 MHz to 10 GHz at temperatures of 283, 293, 303 and 313 K using Time Domain Reflectometry (TDR) for various concentrations. The Kirkwood correlation factor and excess inverse relaxation time were determined and discussed to yield information on the molecular structure and dynamics of the mixture. The values of the static dielectric constant, relaxation time and the Kirkwood correlation factor decrease with increased concentration of methyl acrylate in alcohol. The Bruggman plot shows a non-linearity of the curves for all the systems studied indicates the heterointeraction which may be due to hydrogen bonding of the OH group of alcohol with C=O of the methyl acrylate. The excess inverse relaxation time values are negative for all the systems at all the temperatures indicates that the solute-solvent interaction hinders the rotation of the dipoles of the system.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3755-3760
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• 2012

Single crystals of lithium potassium phthalate (LiKP) were successfully grown from aqueous solution by solvent evaporation technique. The grown crystals were characterized by single crystal X-ray diffraction. The lithium potassium phthalate $C_{16}\;H_{12}\;K\;Li_3\;O_{11}$ belongs to triclinic system with the following unit-cell dimensions at 298(2) K;$a=7.405(5){\AA}$;$b=9.878(5){\AA}$;$c=13.396(5){\AA}$;${\alpha}=71.778(5)^{\circ}$;${\beta}=87.300(5)^{\circ}$;${\gamma}=85.405(5)^{\circ}$; having a space group P1. Mass spectrometric analysis provides the molecular weight of the compound and possible ways of fragmentations occurs in the compound. Thermal stability of the crystal was also studied by both simultaneous TGA/DTA analyses. The UV-Vis-NIR spectrum shows a good transparency in the whole of Visible and as well as in the near IR range. Third order nonlinear optical studies have also been studied by Z-scan technique. Nonlinear absorption and nonlinear refractive index were found out and the third order bulk susceptibility of compound was also estimated. The results have been discussed in detail.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.251-255
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• 2011

A new and highly stereoselective synthesis of (E)-4'-amino-3,4,5-trimethoxystilbene was achieved by using 3,4,5-trimethoxybenzaldehyde and p-nitrotoluene as starting materials through condensation under solvent-free condition and followed by the reducing of nitro group with the system of $NH_2NH_2/FeCl_3$/C in ethanol. The crystal structure of (E)-4'-amino-3,4,5-trimethoxystilbene was also determined by X-ray diffraction analysis.

• Korean Journal of Agricultural Science
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• v.21 no.1
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• pp.54-59
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• 1994

An antibacterial component was isolated from the roots of evening primrose(Oenothera odorata Jacquin). The component was purified by repeated preparative TLC of the chloroform-extract with solvent system of toluene(7):ethyl acetate(4):formic acid(O.8). NMR spectrum indicated that it is a steroid compound containing radical(-C=C-C=0) and aromatic structures. Its antibacterial activity against strains of the genus Streptococcus was relatively high, the MIC value was 50 acccording to the Hoechst Manual-345, as compared with the other genera such as Staphylococcus and Escherichia.

• ETRI Journal
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• v.35 no.4
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• pp.571-577
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• 2013

The fabrication of a thin-film transistor backplane and a liquid-crystal display using printing processes can eliminate the need for photolithography and offers the potential to reduce the manufacturing costs. In this study, we prepare contact via structures through a poly(methyl methacrylate) polymer insulator layer using inkjet printing. When droplets of silver ink composed of a polymer solvent are placed onto the polymer insulator and annealed at high temperatures, the silver ink penetrates the interior of the polymer and generates conducting paths between the top and bottom metal lines through the partial dissolution and swelling of the polymer. The electrical property of various contact via-hole interconnections is investigated using a semiconductor characterization system.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.81-90
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• 2014

Flexible production system has been expanded to all sectors of economy with the change of labor market and diversification of employment. The unstable employment with irregular work has replaced stable employment with regular work. This study has investigate the impact pathway of the type of employment on health status especially ill-health symptoms experiences. Among the first Korean Working Conditions Survey data, the employee's response data was used to analyze the path way with multiple regression analysis. The result has shown the direct effect of the type of employment on ill-health symptoms experience. Indirect effect of the type of employment was found the pathway via the exposure to noise, high temperature, low temperature, dust, skin contact to chemicals, painful posture, heavy material handling, standing position, repetitive movement of hands. However the exposure to the other hazardous factors such as organic solvent, wholebody vibration, radiation, lifting people, infectious materials were not influenced by the type of employment.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2163-2167
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• 2012

A rapid, specific, and reliable LC-MS/MS-based bioanalytical method was developed and validated in rat plasma for the simultaneous quantitation of amitriptyline and its metabolite nortriptyline. Chromatographic separation of these analytes was achieved on a Gemini C18 column ($50{\times}4.60mm$, $5{\mu}m$) using reversed-phase chromatography. The mobile phase was an isocratic solvent system consisting of 1% formic acid in water and methanol (10:90, v/v), at a flow rate of 0.2 mL/min. The analytical range was set as 0.1-500 ng/mL for amitriptyline and 0.08-500 ng/mL for nortriptyline using a $200{\mu}L$ plasma sample. The accuracy and precision of the assay were in accordance with FDA regulations for the validation of bioanalytical methods. The validated method was successfully applied to a pharmacokinetic study in six rats after oral administration of amitriptyline (15 mg/kg). This method allows laboratory scientists to rapidly determine amitriptyline and nortriptyline concentrations in plasma.

• Journal of the Korean Chemical Society
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• v.21 no.1
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• pp.67-72
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• 1977

Author studied on the isolation technique and properties of the products obtained by the reaction of soybean oil with maleic anhydride. Before studying above purpose, oleic acid and linoleic acid contained in soybean oil were reacted with maleic anhydride. Thin-layer chromatography using silica coated plate and solvent system consisting of petroleum ether-diethyl ether = 7:3∼5:5 (v/v) resulted in good effects on the isolation of maleic anhydride adducts. Four fractions were separated and fraction No. 2 were analyzed by IR & UV spectrophotometer, obtaining the following conclusions. In the case of oleic acid adduct and linoleic acid adduct, it were conjectured that the succinic acid type adduct was formed. In the case of conjugated $C_{18}$ fatty acid adduct, cyclohexene type adduct was formed which differed from oleic acid and linoleic acid adduct.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.503-508
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• 1987

The protonation constants of 3,4 : 9,10-dibenzo-1,12-diaza-5,8-dioxacyclotetradecane $(NenOenH_4)$ and stability constants of its transition metal complexes have been determined by the potentiometric titration in 1 : 1 dioxane-water mixture with 0.1 ionic strength at $25^{\circ}C.$ For a given anion system, the stabilitv constants of the complexes are in the order of $Mn^{2+}<\;Co^{2+}\;< Ni^{2+}\;<\;Cu^{2+}\;>\;Zn^{2+}$, which accords with the Williams-Irving series.

• Journal of Life Science
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• v.20 no.7
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• pp.999-1004
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• 2010

Investigations were carried out on a $\beta$-glucosidase produced by Aspergillus niger under solid-state fermentation conditions as a model of enzyme recovery from fermented wheat bran. The leaching efficiency of distilled water to recover the enzyme from the fermented bran was higher than acetate buffer, citrate buffer, citrate-phosphate buffer and 5% methanol; thus, the conditions were further optimized with distilled water as the extracting agent. After fermented bran was washed three times with distilled water for 1.5 hr each under shaking conditions at 1:5 solid to solvent ratio, a maximum recovery of 0.025 U/g of wheat bran was obtained.