• 대한화학회지
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• 제13권2호
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• pp.141-147
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• 1969

Organophosphorous compounds can be reduced by zinc metal in acidic solution after alkaline hydrolysis. Although phosphates and phosphonates did not evolve any gas, dithioates did evolve hydrogen sulfide and phosphine, thionates and thiolates did evolve only hydrogen sulfide. The evolved gases were qualitatively detected by means of lead acetate and silver nitrate or mercuric bromide papers and determined by spectrophotometrically. The reduction mechanism and analytical method of dithioates were proposed.

• 한국표면공학회지
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• 제35권6호
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• pp.401-407
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• 2002

Most of organic compounds discharged from industrial wastewater are treated by chemical oxidation, adsorption and biodegradable process. This process has been demanded a new advanced environmental wastewater treatment process. From this point of view, an electrochemical oxidation process using electrocatalysts has been developed for the destruction of organic compounds. Through this study, a ruthenium oxide/iridium oxide supported on titanium expanded metal was fabricated by thermal decomposition method and its performance was excellent during this experiment.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.226.3-227
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• 2000

No Abstract, See Full Text

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
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• pp.60-65
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• 2004

The possibility of mechano-chemical synthesis and influence of mechanical activation on thermal synthesis of borides and boron carbides of mass-low metals is investigated. The opportunity of mechanochemical synthesis in the mill AGO-2 of such compounds as Al $B_2$and Ca $C_2$ $B_2$is established. Influence of mechanical activation in the mill SPEX 8000 on synthesis of such compound as $Mg_{0.5}$A $l_{0.5}$ $B_2$is shown. Features of synthesis in systems containing metal magnesium are considered.d.d.

• Bulletin of the Korean Chemical Society
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• 제16권11호
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• pp.1093-1099
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• 1995

The polycondensations of bis(2-hydroxyethyl) naphthalate were kinetically investigated in the presence of various metallic compounds as catalysts at 295 ℃. The effect of the catalyst nature in the polycondensation has been studied. The order of catalytic activity on the formation of poly(ethylene 2,6-naphthalate) was found to be related to the stability constants which are indicated in an index of the catalytic activity.

• Bulletin of the Korean Chemical Society
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• 제25권7호
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• pp.959-964
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• 2004

A low-dimensional metal frequently exhibits a metal-insulator transition through a charge-density-wave (CDW) or a spin-density-wave (SDW) which accompany it's structural changes. The transition temperature is thought to be determined by the amount of energy produced during the transition process and the softness of the original structure. $AMo_4O_6$ (A=K, Sn) are known to be quasi-one dimensional metals which exhibit metalinsulator transitions. The difference of the transition temperatures between $KMo_4O_6$ and $SnMo_4O_6$ (A=K, Sn) is examined by investigating their electronic and structural properties. Fermi surface nesting area and the lattice softness are the governing factors to determine the metal-insulator transition temperature in $AMo_4O_6$ compounds.

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1215-1218
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• 2003

An analysis of the bonding situation in CaM₂P₂ (M=Fe, Ni) with ThCr₂Si₂ structure is made in terms of DOS and COOP plots. The main contributions to covalent bonding are due to M-P and P-P interactions in both compounds. Particularly, the interlayer P-P bonding by variation in the transition metal is examined in more detail. It turns out that the shorter P-P bonds in CaNi₂P₂ form as a result of the decreasing electron delocalization into ${{\sigma}_p}^*$ of P₂ due to the weaker bonding interaction between the metal d and ${{\sigma}_p}^*$ as the metal d band is falling from Fe to Ni.

• 한국분말재료학회지
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• 제6권1호
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• pp.49-55
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• 1999

Al-Cr-Zr nanocomposite metal powders were prepared by mechnical alloying (MA) in order to develop aircraft structure materials with lighter weight and lower cost than the conventional Ti and Ni alloys. The morphological changes and microstrutural evolution of Al-6wt.%Cr-3wt.%Zr nanocomposite metal powders during MA were investigated by SEM, XRD and TEM. The approximately 50$\mu$m sized Al-Cr-Zr nanocomposite metal powders has been formed after 20 h of MA. The individual X-ray diffraction peaks of Al, Cr and Zr were broadened and peak intensitied were decreased as a function of MA time. The observed Al crystallite size by TEM was in the range of 20 nm, which is a simliar value calculated by Scherrer equation. The microhardness of Al-Cr-Zr nanocomposite metal powders increases alomost linearly with increase of the processing time, reaching a saturation hardness value of 127 kg/$mm^2$ after 20 h of processing. The intermetallic compound phase of $Al_3Zr_4$ in the matrix was identifed by XRD and TEM.

• Bulletin of the Korean Chemical Society
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• 제20권7호
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• pp.796-800
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• 1999

Three anthrylazacrown ethers in which the anthracene fluorophore π system is separated from the electron donor atoms by one methylene group were synthesized, and their photophysical study was accomplished. These fluorescent compounds showed a maximum fluorescence intensity at pH=5 in aqueous solutions and a decrease in fluorescence intensity upon binding of paramagnetic metal cations (Mn 2+ (d 5 ), Co 2+ (d 7 ), Cu 2+ (d 9 )). The decrease in fluorescence intensity may be attributed to the paramagnetic effect of metal cations to deactivate the excited state by the nonradiative quenching process. The benzylic nitrogen was found to play an important role in changing fluorescence intensity. From the observed linear Stern-Volmer plot and the fluorescence lifetime independence of the presence of metal ions, it was inferred that the chelation enhanced fluorescence quenching (CHEQ) mechanism in the system is a ground state static quenching process. Enhanced fluorescence was also observed when an excess Na + ion was added to the quenched aqueous solution, and it was attributed to cation displacement of a complexed fluorescence quencher.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.515-522
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• 2005

Enzyme-metal combo catalysis is described as a useful methodology for the synthesis of optically active compounds. The key point of the method is the use of enzyme and metal in combination as the catalysts for the complete transformation of racemic substrates to single enantiomeric products through dynamic kinetic resolution (DKR). In this approach, enzyme acts as an enantioselective resolving catalyst and metal does as a racemizing catalyst for the efficient DKR. Three kinds of enzyme-metal combinations - lipase-ruthenium, subtilisin-ruthenium, and lipase-palladium –have been developed as the catalysts for the DKRs of racemic alcohols, esters, and amines. The scope of the combination catalysts can be extended to the asymmetric transformations of ketones, enol acetates, and ketoximes via the DKRs. In most cases studied, enzyme-metal combo catalysis provided enantiomerically-enriched products in high yields.