• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.326-333
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• 1978

m-Phenylenedihydrazine(MPDH) was prepared via tetrazonium salt: m-Phenylenediamine was tetrazotized with sodium nitrite at $-10∼-5^{\circ}C$ in concentrated hydrochloric acid medium, reused tetrazonium salt was reduced with stannous chloride and MPDH was separated as dihydrochloride which was recrystallized from alcohol. The free base of MPDH being unstable it could hardly be obtained in the air. $MPDH{\cdot}2HCl$ did not show sharp melting point but decomposed at $185^{\circ}C$. MPDH, like aromatic monohydrazines, condensed with mono-and dicarbonyl compounds giving dihydrazones or cyclic compounds. The structures of condensation products obtained from the reaction of MPDH with carbonyl compounds are determined.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.723-726
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• 2010

An efficient and simplified protocol for $NaHSO_4/SiO_2$ catalyzed solvent-free synthesis of $\beta$-enaminone and 2-methylquinolin-4(1H)-one derivatives under microwave irradiation is described. A series of functionalized derivatives have been synthesized in shorter reaction times with moderate to good yields. The use of milder catalyst in non-conventional method offers significant advantages over conventional methods, such as higher selectivities, simplicity, solvent-free reaction and non-environmental polluting conditions.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.509-514
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• 1999

In Preparing $BaTiO_3$ powder under hydrothermal conditions, effects of reaction period feedstock concentration and mixing rate on crystallinity, mean size and size distribution of particles were studied. Experimental results showed that the particle size became smaller with its narrow distribution as the reaction period and mixing rate increased, but feedstock concentration decreased in contrast with the results based on the classical nucleation-growth model. From these results, $BaTiO_3$ particles seem to be prepared hydrothermally through a multiple reaction procedure that includes dissolution, precipitation, hydrolysis-condensation, aggregation, diffusion and transformation.

• Journal of the Korean Ceramic Society
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• v.28 no.11
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• pp.865-872
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• 1991

LAS (lithium aluminosilicate) sol was synthesized using the hydrolysis-condensation reaction of TEOS, chelated Al(OBus)3 and LiNO3 with H2O in alcohol (ethanol+2-propanol) medium. Lowering Li content by a factor of 1/2 significantly enhanced densification and retarded the crystallization of LAS gel by ~30$0^{\circ}C$. Dense LAS specimen with essentially pore-free microstructure was obtained by sintering the sol-gel derived gel at 80$0^{\circ}C$ for 4 h and annealing at 120$0^{\circ}C$ for 2 h. Similary, a mixed colloidal processing was attempted as a convenient, alternative route for the fabrication of dense LAS sintered body. The $\beta$-spodumene seeding (~0.8 ${\mu}{\textrm}{m}$) in the sol-gel derived LAS modified the sequence of phase transformations and lowered the temperature of crystallization by ~12$0^{\circ}C$. Combining the epitaxial seeding with the sol-gel process, we could lower the crystallization temperature to the sintering temperature range (~80$0^{\circ}C$) and, demonstrate a possibility of making the viscous sintering/crystallization as a continuous as a continuous unit process.

• Journal of the Korean Chemical Society
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• v.19 no.6
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• pp.438-442
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• 1975

The syntheses of anomeric mixtures of 1-(4-thio-${\alpha},{\beta}$-D-ribofuranosyl)-5-fluoro-and 5-chlorouracils from their corresponding bis(trimethylsilyl) derivatives of 5-halogenouracils and 2,3,5-tri-O-acetyl-4-thio-${\alpha},{\beta}$-D-ribofuranosyl chloride are described. Preliminary biochemical studies showed that in leukemia 1210 cells and Streptococcus faecium, the ${\beta}$-anomeric 5-chloro-4'-thionucleoside is not greatly different from the corresponding 4'-oxygen analog. However, the 5-fluoro-4'-thionucleoside showed a growth inhibitory effect more than that of the oxygen counterpart. The potential chemotherapeutic use of the analog is to warrant further study.

• Polymer(Korea)
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• v.30 no.1
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• pp.1-9
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• 2006

The development of functional polymeric materials for biomedical application has progressed on the basis of functionality, biocompatibility and biodegradability. In this paper we review the functional polymeric biomaterialsbased systems and propose a range of biomedical applications in the near future. These systems include the functional biodegradable polymers synthesized in our research laboratory, biodegradable polymeric materials, thermosensitive polymeric materials, cationic polymeric materials, non-condensing polymeric biomaterials, bio-polymeric DNA matrix for tissue engineering, and polymeric biomaterials for RNA interference (RNAi) technology.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.670-674
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• 2009

3-Chromonealdehyde(2,2-disubstituted)hydrazone derivatives were synthesized by dehydration condensation. They are green-emitting materials for organic light emitting device (OLED) composed of electron acceptor of 3-chromonealdehydes and electron donor of 2,2-disubstituted hydrazones by a conjugated structure. The structural properties of reaction products were analyzed FT-IR and $^1H-NMR$ spectroscopy. The thermal stabilities and reactivities were measured by melting points and yields. The UV-visibles and PL properties can be determined by excitation spectra and emission spectra, respectively.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.134-139
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• 2009

A series of allylidenethiosemicarbazone compounds (2a~2e) were obtained in 45~85% by condensing (E)-3-(aryl)acrylaldehyde (1a~1e) with thiosemicarbazide. Theses compounds on treatment of 2,4'-dibromoacetophenone and 2,3-dichloroquinoxaline yielded 2,4-disubstituted thiazoles (3a~3e) and 2-[(E)-3-(aryl)allylidenehydrazono]thiazolo[5,4-b]quinoxaline (4a~4e) in good yield respectively. The structures of all the newly synthesized compounds were identified by IR and $^1H-NMR$ spectral data.

• Korean Journal of Microbiology
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• v.35 no.1
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• pp.65-71
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• 1999

This study was carried out utilzing ability of sole carbon sources in soil microbial communities used by Biolog GN microplate. Cluster analysis showed that soil microbial cornmuties were categorized into three groups as forest, non-forest soil and naked soil of microbial group. Soil microbial commutites in a forest soil of Qirercus mongoIica was divided into another group microbial communites in Qirercus dendata vegetation soil and Pinus dnzsqlora vegetation soil by Multidimensional scaling(MDS). Generally, sole carbon utilzing abilties were higher in order of polymer, amino acids and carboxylic acids, but it was lower in amides substrates carbon group. From the result: it was supposed that metabolic diversity of microbial communities was corresponded to vegetation succession.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.609-613
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• 2006

4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) derivatives were synthesized by Knoevenagel condensation. They are red-emitting materials for OLED (Organic Light-Emitting Diode) composed of electron donor of aminostyryl groups and electron acceptor of two cyano(nitrile)groups in a conjugated structure. The structural properties of reaction products were analyzed by FT-IR and $^1H-NMR$ spectroscopy. The thermal stabilities and reactivities were measured by melting points and yields. The UV-visible and PL properties can be determined by exitation and emission spectra, respectively.