• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.138-160
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• 2001

In this study we measured oxidation potentials and current densities for poly(vinylcholride) (PVC) and poly(carbonate)(PC) in nonaqueous solutions, in order to find out how corrosion (oxidation) potentials depend on temperature, pH, enzyme, or added salts. The Tafel's slopes were determined from the Tafel plots of polarization curves. The transfer coefficients (${\alpha}$) wre evaluated from the slope(1-${\alpha}$)nF/2.3 RT, and the electrode reactions appeared irreversible under all conditions.

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.537-544
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• 2001

뮬라이트, 지르코니아, 뮬라이트/지르코니아 비수성 현탁액의 분산 및 레올로지에 미치는 공정보조제의 영향이 침전밀도, 점도, 입자크기를 측정함으로써 검토되었다. 현탁액의 분산안정성 (높은 침전밀도와 낮은 점도로 특징 된)은 분산제+가소제+결합제를 함유하는 경우에 비하여 분산제 또는 분산제+가소제를 함유하는 경우가 우수하였다. Ball mulling 후의 입자크기분포는 공정보조제의 종류에 거의 영향을 받지 않았다. 결합제를 부가적으로 함유하는 현탁액은 상대적으로 강한 shear thinning 거동을 나타내었다.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.192-196
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• 2002

Ionic liquids based on l-ethyl-3-methylimidazolium cation $(EMI^+)$ and inorganic or organic anions containing fluorine atoms were applied to electrolyte materials for double-layer capacitors. The double-layer capacitors composed of a pair of activated carbon electrodes and an ionic liquid selected from $EMIBF_4,\; EMINbF_6,\;EMITaF_6,\;EMICF_3SO_3,\;EMI(CF_3SO_2)_2N,\;and\;EMI(C_2F_5SO_2)_2N$ showed inferior low-temperature characteristics to those of a conventional nonaqueous electrolyte based on propylene carbonate (PC) solvent. On the other hand, the capacitor using $EMIF{\cdot}2.3HF$ showed excellent low-temperature characteristics due to its high conductivity at low temperatures, however, it had a lower working voltage $(\~2V)$ than the conventional nonaqueous counterpart $(\~3V)$.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.831-834
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• 1995

The nature of hydrogen bonding between thioacetamide and azines has been thoroughly investigated using near IR absorption spectroscopy. The νN-H + amide II combination band in thioacetamide (TA) has been analyzed to determine the thermodynamic constants for the formation of hydrogen bonded 1:1 TA:azine complexes in CCl4 and CHCl3 solutions. The relative stabilities of TA-azine complexes (pyridine->1,2-diazine->1,3-diazine->1,4-diazine-TA) are in good agreement with the relative proton affinities of azines in the gas phase. The results serve as a basis for analyzing the factors which influence the hydrogen bonding formation of TA in nonaqueous solutions.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1483-1486
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• 1999

The contents of pentachlorophenol (PCP) and 2,3,5,6-tetrachlorophenol (TeCP) in textile products are regulated for safety. Since an organic solvent such as 2-methoxyethanol is needed to extract chlorinated phenols from textile samples, nonaqueous capillary electrophoresis has been applied to achieve the separation of PCP and isomers of TeCP. The run buffer was 100 mM Tris/acetate in methanol whose pH was adjusted to 8.0. All of the analytes were negatively charged at pH 8.0 and their electrophoretic velocities were higher than the electroosmotic flow of the methanol buffer. A reverse voltage of -20 kV was applied along a 27-cm fused silica capillary with ID of 50 μm, and PCP and 3 TeCP isomers were separated based on the difference in $pK_a$ values in less than 4 min. The limits of detection (S/N = 3) were about 0.02 μM. By varying pH of the methanol run buffer, $pK_a$ values of the 4 chlorinated phenols were also estimated.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.212-217
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• 1998

The electrochemistry and valence tautomerism of CoⅢ(N-N)(SQ)(Cat), [N-N=N,N,N',N'-tetramethylethylenediamine (TMEDA); SQ=3,5- or 3,6-di-tert-butyl-semiquinone, Cat=3,5- or 3,6-di-tert-butyl-catechol], have been investigated by spectroscopic, electrochemical, spectroelectrochemical methods in nonaqueous solvents under anaerobic condition. The transition temperature between tautomers is dependent upon the donation effect of substituted quinone ligand and solvent. It increases with the increase of donation effect of solvent and quinone ligand. CoⅢ(TMEDA)(SQ)(Cat) is reduced to [CoⅡ(TMEDA)(SQ)(Cat)]-, and then reduces to [CoⅡ(TMEDA)(Cat)2]2-. CoⅢ(TMEDA)(SQ)(Cat) is oxidized to [CoⅢ(TMEDA)(SQ)2]+, but the stability of the oxidized form in DMF is dependent upon the solution temperature. With the increase of solution temperatrue the oxidized form may be converted to [CoⅡ(TMEDA)(SQ)(BQ)]+ by intramolecular electron transfer from SQ ligand to CoⅢ.

• 한국전기화학회:학술대회논문집
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• 2003.11a
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• pp.79-90
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• 2003

• Environmental Engineering Research
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• v.9 no.5
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• pp.214-222
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• 2004

• Bulletin of the Korean Chemical Society
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• v.7 no.4
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• pp.320-321
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• 1986

• Korean Journal of Materials Research
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• v.15 no.5
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• pp.334-339
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• 2005

Nickel Powders were synthesized by the reduction of $Ni(OH)_2$ reactant slurries from nonaqueous media, and the morphological characteristics of nickel powders with the addition of NaOH, the composition of mixed solvents, reaction temperature and reaction time were investigated. The NaOH addition changed the structure of agglomeration in the submicron range. As the volume ratio of TEA to DEA increased, the powders slightly suppressed the agglomeration between particles and their size increased. The reaction temperature on size and shape of nickel powders was significant. As reaction time was shortened from 40 min to 0.3 min at $220^{\circ}C$, size distribution of nickel powders was transferred to a narrow size distribution owing to the presence of smaller particles with below $1.0\;{\mu}m$.