• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.286-289
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• 2000

Surfactants have been extensively considered for decontamination of the subsurface polluted with hydrophobic organic compounds. Enhanced solubilization of naphthalene and phenanthrene in surfactant solution of SDDBS, MADS12 and DADS12 was studied for single compounds and their binary mixture. The order of increasing solubility enhancement of naphthalene and phenanthrene is SDDBS < MADS12 < DADS12. The solubility enhancement of phenanthrene is more than that of naphthalene because of the higher hydrophobicity. A synergistic effect on the solubilization of two PAHs was observed in the presence of another PAH.

• The Korean Journal of Food And Nutrition
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• v.5 no.1
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• pp.23-32
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• 1992

Kinetic studies of nucleophilic substitution reactions of dansyl, bansyl, dabsyl chlorides with pyridines have been investigated at $0^{\circ}C$ in a range of methanol-acetonitrile binary solvent mixtures. The order of magnitude for reactivity of substrates with pyridines in the same reaction condition is dabsyl chloride>dansyl chloride> bansyl chloride. The value of $\rho$n(-2.29~ -4.66) and $\beta$(0.537~0.901) associated with a change substituent in the nucleophile are large and indicate a relatively advanced bond formation in the transition state. Solvatochromic correlations were predicted the increase of bond formation transition state according to the increasing MeCN contents, showing the greater contribution of polarity polarizability ($\pi$*) than hydro-gen bond donar acidity($\alpha$). We conclude that the reactions of dansyl, bansyl, dabsyl chlorides with pyridines proceed via associative Sn2 type reaction mechanism.

• New & Renewable Energy
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• v.3 no.2 s.10
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• pp.47-52
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• 2007

Hydrate phase equilibrium for the binary $CO_{2}$+water and $CH_{4}$+water mixtures in silica gel pore of nominal 6, 30, and 100 nm were measured and compared with the cacluated results based on van der Waals and Platteeuw model. At a specific temperature three-phase hydrate-water-vapor (HLV) equilibrium curves for pore hydrates were shifted to the higher-pressure condition depending on pore sizes when compared with those of bulk hydrates. Notably, hydrate phase equilibria for the case of 100 nominal nm pore size were nearly identical with those of bulk hydrates. The activities of water in porous silica gels were modified to account for capillary effect, and the calculation results were generally in good agreement with the experimental data.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.233-234
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• 2003

There are many advantages of dyebath-reuse, including less water to heat, less effluent to treat, and a reduced consumption of energy, dyes, and chemical auxiliaries. Because of the potential economic and environmental advantages involved in this process, clearly it is deserving of further investigation. Dyebath-reuse using pH-sliding system has been investigated in the dyeing of polyamide with a single acid dye in a previous study. (omitted)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.401-404
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• 1996

Optical absorption were performed on LB films of binary mixtures of three kinds of merocyanine dyes [DO], [DS], and [6Me-DS], where [DS] and [6Me-DS] from J-like aggregates but not [DO] in single component films. The observed optical absorption spectra of mixed films were markedly dependent on the combination of dyes. [DS]$_{1-x}$ [DO]$_{x}$ LB films show a sharp red shift J-like band peak in the while concentration range. We found the formation of J-aggregates in a mixed merocyanine dyes containing a non J-aggregate forming dye [DO], in a single component case. Further investigations on the present and other mixed dye films will be needed to clarify these points.ts.

• Journal of the Korean Chemical Society
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• v.21 no.2
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• pp.83-88
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• 1977

Kinetic studies on the rates of reactions of 2, 4-dinitrochlorobenzene with p-toluidine, aniline and p-chloroaniline in $CH_3CH-CH_3OH$ binary solvent mixtures have been carried out. The experimental results have been explained in terms of the specific solvation by alcoholic hydrogen. It has been shown that the bond breaking step is rate determining in the solvent system studied and the energy barrier is getting low as the solvent changes from acetonitrile to methanol.

• Journal of Ginseng Research
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• v.18 no.3
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• pp.196-199
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• 1994

A study was designed to investigate the sorption characteristics of binary mixture of red ginseng powder and maltodextrin(DE-17) or lactose stored at various relative humidities ranging from 52% to 93%. At low relative humilities below RH 67%, the sorption equilibrium was easily achieved, whereas at higher relative humidity values over 75%, all of the mixtures tended to absorb moisture continuously with an increase in storage time. A linear equation of log(dw/dt): a log(t)+ log b was found to be valid between the sorption rate and storage time with respect to storage humilities. A linearity was also found between log(1-Aw) and the amount of water absorbed over the Aw range of 0.52∼0.93 and the slope was affected by the kind of sugar added with that of red ginseng powder and maltodextrin mixture being the smallest.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.35-39
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• 2013

The flash point is an important indicator of the flammability of a chemical. In this study, the flash points for the n-propanol+n-butanol and n-propanol+acetic acid systems were measured by Tag open-cup apparatus. The experimental data were compared with the values calculated by the Raoult's law and optimization method based on van Laar and UNIQUAC equations. The calculated values by optimization method were found to be better than those based on the Raoult's law.

• Bulletin of the Korean Chemical Society
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• v.1 no.3
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• pp.101-104
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• 1980

A sequential copolypeptide with repeating unit sequences, in which a glycyl residue is flanked progressively by two ${\gamma}$-benzyl-L-glutamyl residues, has been synthesized by poymerizing p-nitrophenyl ester of ${\gamma}$-benzyl-L-glutamyl-${\gamma}$ -benzyl-L-gutamyl-glycine. Polymers obtained were characterized by viscosity and infra-red spectral data. The highest molecular weight obtained was 21,000. Molecular conformation in solid state was found to be a mixed form of and |${\beta}$-structure. Polymers obtained were insoluble in the most of the organic solvents except in a strong acid like dichloroacetic acid, but in binary mixtures of solvents such as dichloroacetic acid-ethylene dichloride or dichloroacetic acid-chloroform, they were soluble within certain ranges of solvent compositions.

• Analytical Science and Technology
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• v.34 no.2
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• pp.46-55
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• 2021

Evaluation of drug-excipient compatibility is one of the basic steps in the preformulation of pharmaceutical dosage forms. Some reactive excipients have been known so far which may cause stability problems for drug molecules in pharmaceutical dosage forms. The aim of this study was to evaluate drugexcipient compatibility of gliclazide with some common pharmaceutical excipients, known for their ability to incorporate in drug-excipient interactions. Binary mixtures were prepared using lactose, magnesium stearate, polyvinylpyrrolidone, sodium starch glycolate, polyethylene glycol 2000 and dicalcium phosphate. Based on the results; gliclazide was incompatible with all tested excipients; but not with dicalcium phosphate. DSC (Differential Scanning Calorimetry) results were in accordance with HPLC (High Pressure liquid chromatography) data and were more predictive than FTIR (Fourier Transform Infrared Spectroscopy). Drug and reactive excipients incompatibility was fully discussed and documented. It is advisable to avoid incompatible excipients or carefully monitor the drug stability when incorporating such excipients in final formulation designs.