• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1821-1826
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• 2009

Liquid crystal display (LCD) devices contain a colour filter which can visualise colour images by transmitting or absorbing light. Colour properties of LCD mainly depend on colour materials such as pigments and polymeric binders. In this paper, colour properties were studied to improve colour quality of LCD. Generally, the colour properties can be classified into three categories which are colour purity, brightness and contrast ratio. For this study, photo resists were prepared by treatment of pigments and synthesis of polymeric binder. The treated pigments were dispersed and formulated with additives for preparing a photo resist that could be used for manufacturing colour filters. As a result of what we studied, type, mixture ratio and concentration of pigments were very important to improve colour purity of LCD device.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.846-848
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• 2009

Two modifications of the ${\alpha}\;and\;{\beta}$ forms of propyl mercaptan nickel(II) cluster, [$Ni_6(SCH_2CH_2CH_3)_{12}$], have been synthesized and their crystal structures have been determined by single-crystal X-ray diffraction. The alkyl groups are away from $Ni_6$ ring in $\alpha$ form whereas they are near to the Ni atom in $\beta$ form. The distance of Ni-H in $\beta$ form [2.576(5) $\AA$] is much shorter than that in $\alpha$ form [3.101(2) $\AA$]. In the crystal lattice of $\beta$ form, the whole structure forms a flower shape.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.1
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• pp.193-195
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• 2006

The effects of ethanol extract from Lepidolaena clavigera (L. clavigera) on antifungal activity were investigated. The crude ethanol extract of L. clavigera inhibited the growth of the Gram positive bacterium Bacillus subtilis ATCC 19659, (1 mm inhibition zone at 150 ${\mu}g/disc$) and the dermatophytic fungus Trichophyon mentagrophyes ATCC 28185, (2 mm inhibition zone at 150 ${\mu}g/disc$), and cytotoxic to P388 murine leukaemia cells ATCC CCL 46 P388D1, (IC50 >12,500 ${\mu}g/mL\;at\;150\;{\mu}g/disc$) and cytotoxic to BSC monkey kidney cells (@ 5 mg/mL, 150 ${\mu}g/disc$; ++: 50% activity). We suppose that this crude ethanol extract of L. clavigera is the antifungal activity.

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.22-26
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• 1992

The solution structures of the vanadium(V) complexes of iminodiacetate analogues, such as iminodiacetate (IDA), methyliminodiacetate (MeIDA), ethyliminodiacetate (EtIDA), benzyliminodiacetate (BzIDA), pyridine-2,6-dicarboxylate (DPA), and 2-hydroxyethyliminodiacetate (HEIDA), have been studied by $^{13}C-$ and $^{51}V$-NMR spectroscopy. Assuming that the complexes have a $cis-VO_2$ core, IDA, MeIDA, EtIDA, and BzIDA act as facial tridentate ligands to form octahedral complexes, whereas DPA coordinates to $VO_2^+$ as a meridional tridentate. And one water molecule fulfills the remaining site to satisfy the coordination number of six. But HEIDA coordinates to $VO_2^+$ through one IDA moiety and one hydroxyl group, acting as a tetradenate.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.396-399
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• 1990

Fourier transform infrared spectroscopy has been applied to the characterization of titania surface. The bands due to surface OH groups were observed to be more intense in the reduced titania than in the oxidized titania. The IR spectra of CO adsorbed on titania exhibited two C-O stretching bands, namely at 2187 and 2209 cm$^{-1}$. The intensities were stronger in the oxidized titania.The 2187 cm$^{-1}$-peak was attributed to CO coordinated to $Ti^{4+}_{5c}$ (subscriptindicates the coordination number of the coordinatively unsaturated cation by oxygen ions), while the 2209 cm-1-peak due to the $Ti^{4+}_{4c}{\cdots}$CO complex.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.1
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• pp.61-68
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• 2019

Purine type compounds has been recently reported to cause the death for lung cancer cell, related to microtubules-targeting agents (MTAs). Therefore it can be used to develop as theranostic radiopharmceuticals in nuclear medicine or gadolinium-based MRI imaging agents by chelate chemistry. In the study, we tried to chemically bind a DOTA chelate on the end of purine compound and obtained a specific conjugate of DOTA-purine for metal coordination. In particular, radiometal like Cu-64, for the development of MRI imaging agents, can be utilized to choice good candidates before the synthesis of gadolinium complexes. By the screening of radioisotope technique, Gd-DOTA-purine type complex was successfully prepared and showed MRI imaging for lung cancer cell into the mouse model.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.274-279
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• 1992

Immobilization method of lariat azacrown ethers, containing hydroxyl group in the side arm of crown ring, on the polymer matrix and the phase-transfer catalytic activity of thus obtained immobilized lariat azacrown ethers were studied. Polystyrene resins with crown ether structures and hydroxyl groups adjacent to the macrorings were prepared by the reaction of crosslinked polystyrene resins containing epoxy groups with monoaza-15-crown-5 or monoaza-18-crown-6. Microporous crosslinked polystyrene resins containing epoxy group for the syntheses of these immobilized lariat crown catalysts were prepared by suspension polymerization of styrene, divinylbenzene (DVB 2%) and vinylbenzylglycidyl ether. The immobilized lariat catalysts with 10-20% ring substitution exhibited maximal activity for the halogen exchange reactions of 1-bromooctane with aqueous KI or NaI under triphase heterogeneous conditions. Immobilized catalyst exhibited higher activity than corresponding catalyst without the hydroxyl group and this result was suggested that the active site have a structure in which the $K^+$ ion was bound by the cooperative coordination of the crown ring donors and the hydroxyl group in the side arm.

• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.181-195
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• 2020

Characteristics of carbonized biomass obtained from a Wood charcoal briquette manufacturing process using an open hearth kiln are analyzed in this research, and differences in the characteristics based on the results of a mechanical screening process and the position within the kiln. One type of biomass and five types of carbonized biomass were collected from a Wood charcoal briquette manufacturer. After screening and grinding processes were performed on samples of 1 type of biomass and 5 types of carbonized biomass extracted from a Wood charcoal briquettes manufacturer to classify by particle size, fixed carbon, ash, volatile matters, elemental composition, and high heating value (HHV) were measured. Experimental results showed that the carbonized biomass collected from the middle layer had the highest HHV, 20.4 MJ/kg, and therefore had the highest fuel quality. In terms of particle size, the carbonized biomass below 100 mesh had the lowest ash content and the highest HHV, carbon content, and fixed carbon content. Correlation analyses showed that ash content had negative correlations with HHV, volatile matters, fixed carbon, and carbon content, which suggested that ash content affected negatively on fuel quality.

• Journal of the Korean Chemical Society
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• v.66 no.2
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• pp.124-135
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• 2022

The purpose of this study was to analyze the chemisry education contents of South Korea and North Korea for understanding chemistry education of North Korea. Chemistry education in South and North Korea was investigated in terms of learning period and learning quantaty. Especially, what content North Korea learned prior to South Korea and what contents learned more were analyzed. The subjects of this study were South Korean 2015 revised National Science Curriculum and North Korean science textbooks in Kim Jong-un era. The North Korean textbooks analyzed are 'Nature' for North Korean elementary school 3, 'Natural Science' for North Korean middle school 1 and 2, and 'Chemistry' for North Korean high school 1 and 2. The analysis results are as follows. First, the content elements to be learned in advance in North Korean textbooks were density, oxidation and reduction, battery, and atomic weight. Second, the content elements additionally learned in North Korean textbooks include separation of mixtures, fuels, oxidation and reduction, metals, organic and inorganic substances, metals and non-metal oxides and hydroxides, inorganic substances used as fertilizers, nutritional substances, and salt reaction and utilization, atomic orbitals, hybridization of orbitals, coordination bonds and complexes. As a future research task, a qualitative analysis of the elements of North Korean chemistry, the activities of textbooks, and an experimental analysis were proposed.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.303-308
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• 2010

Pseudo-first-order rate constants ($k_{obsd}$) have been measured spectrophotometrically for nucleophilic substitution reactions of 4-nitrophenyl benzoate (5a), 4-nitrophenyl 4-methoxybenzoate (5b), and 4-nitrophenyl 4-hydroxybenzoate (5c) with alkali metal ethoxides, $EtO^-M^+$ ($M^+=Li^+$, $Na^+$ and $K^+$) in anhydrous ethanol (EtOH) at $25.0{\pm}0.1^{\circ}C$. The plots of $k_{obsd}$ vs. [$EtO^-M^+$] exhibit upward curvatures in all cases, indicating that $M^+$ ions catalyze the reactions and ionpaired $EtO^-M^+$ species are more reactive than dissociated $EtO^-$. Second-order rate constants for reactions with dissociated $EtO^-$ and ion-paired $EtO^-M^+$ (i.e., $k_{EtO^-}$ and $k_{EtO^-M^+}$, respectively) have been calculated from ion-pair treatment for the reactions of 5a and 5b. However, such ion-pair treatment has failed to determine $k_{EtO^-}$ and $k_{EtO^-M^+}$ values for the reactions of 5c. It has been concluded that reactions of 5a and 5b are catalyzed by one metal ion, which increases electrophilicity of the reaction center through coordination on the carbonyl oxygen. In contrast, reactions of 5c have been suggested to involve two metal ions, i.e., the one coordinated on the carbonyl oxygen increases the electrophilicity of the reaction center while the other one associated on the phenoxy oxygen decreases the charge repulsion between the anionic reagents (i.e., $EtO^-$ and deprotonated 5c). It has been found that the rate equation derived from the mechanism involving two metal ions fits nicely to the kinetic results obtained for the reactions of 5c.