• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.898-904
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• 2003

This study was conducted to observe the effect of various kinds of sugars and their molar concentrations on the Maillard browning reaction. To observe the effects of various kinds of sugar, glucose, fructose, tagatose, xylose, and sucrose were employed. A model solution consisting of 0.2 M sugar and 0.2 M glycine was prepared and heated at $100^{\circ}C$ for 5 hr. The model solution with adjusted concentrations of either tagatose or glycine was also heated at $100^{\circ}C$ for 5 hr. Tagatose showed the fastest Maillard reaction, followed by xylose, fructose, glucose, and sucrose. After glycine concentration of the model solution was fixed, the model solution showed more browning with an increase in tagatose concentration. When the tagatose concentration of the model solution was fixed, the model solution showed more browning with an increase in glycine concentration. The model solution with a fixed concentration of glycine showed more more browning than that with a fixed concentration of tagatose, since the former had higher amounts of the reactant.

• YAKHAK HOEJI
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• v.28 no.6
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• pp.299-303
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• 1984

In order to eluciate the effect of humidity and organic solvent on the decomposition of carbamide peroxide, the kinetic study was carried out. The carbamide peroxide was prepared from urea and 30%-hydrogen peroxide. The accelerated stability analysis for carbamide peroxide crystal in various relative humidity, and for 10%-carbamide peroxide solution of organic solvents were investigated. Both humidity and temperature were important factors influencing the decomposition rate of carbamide peroxide crystal. The higher the humidity and temperature, the greater was the reaction rate. The breakdown rate of crystal was observed as an apparent zero-order, and was faster than the rate of decomposition in dilute propylene glycol, glycerine or sorbitol solutioos which were measured as an apparent first-order reaction. The more dilute to 10% the organic solvents of 10%-carbamide peroxide, the slower was breakdown rate. It is, therefore, useful in the aspects of stability and economics to substitute solvent of carbamide peroxide topical solution (USP XXI) with 10%-propylene glycol or glycerine instead of anhydrous glycerine.

• Analytical Science and Technology
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• v.9 no.1
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• pp.62-71
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• 1996

The enhancement of the solar energy conversion efficiency into the electrical energy by the dye sensitization with a photoelectrochemical cell was studied. The magnitude of the rose bengal sensitized photocurrent containing the supersensitizer, thiourea was five times greater than that in the absence of thiourea. It was observed, however, that the long time span of irradiation causes the decrease in the photocurrent. Spectroscopic analysis of the dye solution showed that the dye molecule was photobleached and the insoluble aggregate which settles down in the solution, was formed as a result of the possible photocatalytic reaction and the disappearance of dye from the solution was the cause of the decreased photocurrent in the sensitization run.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.505-512
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• 1997

The Interfacial characteristics between various heavy metals and hydrous FeS were investigated. Heavy metals which have lower sulfide solubilities than FeS undergoes the lecttice exchange reaction when these metal tons contact FeS In the aqueous phase. For heavy metals which have higher suede solubilities than FeS, these metal ions adsorb on the surface of FeS. Such characteristic reactions were interpreted by the soled solution formation theory. The presence of ligand such as EDTA reduced largely metal removal efficiency due to formation of metal-ligand complex In the solution. In an attempt to elucidate the Interfacial characteristics, zeta potential of the hydrous FeS In the absence and In the presence of various metal loons were measured and analyzed.

• Journal of Powder Materials
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• v.10 no.5
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• pp.310-317
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• 2003

Two-component ceramic (alumina-zirconia) composites were fabricated by a soft-solution process in which polyethylene glycol (PEG) was used as a polymeric carrier. Metal salts and PEG were dissolved in ethyl alcohol without any precipitation in 1:1 volume ratio of alumina and zirconia. In the non-aqueous system, the flammable solvent made explosive, exothermic reaction during drying process. The reaction resulted in formation of volume expanded, porous precursor powders by a vigorous decomposition of organic components in the precursor sol. The PEG content affected the grain size of sintered composites as well as the morphology of precursor powders. The difference of microstructure in sintered composite was attribute to the solubility and homogeneity of metal cations in precursor sol. At the optimum amount of the PEG polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. It made less agglomerated particles in the precursor sol and affected on uniform grain size in sintered composite.

• Journal of the Korean Society of Safety
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• v.13 no.2
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• pp.109-115
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• 1998

Tri-cresyl phosphate(TCP) was synthesized by reaction of phosphorus chloride with mixed cresol(mixture of m-cresol, p-cresol, and others) in the presence of $AlCl_3$. Some of unwanted products and unreactants colored TCP. In order to separate TCP from these, vaccume distillation was carried twice, but colorless TCP could not be producted. Separation of unwanted materials by 2% NaOH solution was introduced before first and second distillation and optimal separation conditions such as NaOH concentration, mixing volume ratio, mixing time, and rpm were investigated for new batch separation and production of colorless TCP Optimal conditions were 2% NaOH solution, 35% mixing volume ratio of 2% NaOH solution, 1.5 hours of mixing time, and 20 rpm.

• Journal of Pharmaceutical Investigation
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• v.11 no.3
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• pp.21-26
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• 1981

The rate of decomposition of calcium thioglycollate in aqueous solution was shown to increase with increasing temperature and with diluting concentration of calcium thioglycollate. The effect of additive on oxidation rate of calcium thioglycollate was studied to prepare the more stable depilatory formula using additives, such as thiourea, mannitol, sodium thiocyanide, nicotinamide, triethanolamine and ethylenediamine. In all cases, the rate of oxidation was reduced when the additive was present in the solution, among them triethanolamine and ethylenediamine inhibited the decomposition rate remarkably. It is assumed that the decomposition reaction in aqueous solution is pseudo-first order reaction.

• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.4-6
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• 1999

We have performed spin-spray ferrite plating of $Fe_{3-x}Zn_xO_4$($X=0.47{\sim}0.97$) films in the temperature region T=85[$^{\circ}C$]. A reaction solution and an oxidizing solution were supplied to a reaction chamber by supply pumps. The Zn composition X in the $Fe_{3-x}Zn_xO_4$ Film increases as the content of $ZnCl_2$ increase, from X=0.47 at O.05[g/l] to X=0.97 at 0.15[g/l]. All the films are polycrystalline with no preferential orientation, and the magnetization exhibits no definite anisotropy. Grain size in the films increases as X increases, reaching 0.98[${\mu}m$] at X=0.97.

• Journal of the Korean Ceramic Society
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• v.18 no.2
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• pp.105-111
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• 1981

The iron precipitates were prepared by adding sodium carbonate solution to ferrous chloride and ferric chloride solutions to pH=9 and pH=4.5, respectively. The thermal reaction of the iron precipitates was investigated by means of TGA, DTA and X-ray diffraction. In the former the crystallization of $\alpha$-$Fe_2O_3$ begins at about 35$0^{\circ}C$, while in the latter at about 30$0^{\circ}C$, during the calclnation in air. In the iron precipitate from ferrous chloride solution, the activation energy for the crystallite-growth or $\alpha$-TEX>$Fe_2O_3$ in air is about 7.6$\times$104J/mole between 800 and 100$0^{\circ}C$. As the result of X-ray diffration for the reduction product of hematite, it was found that maghemite, magnetite and wustite are formed and that hematite is transformed to magnetite through maghemite.

• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.403-407
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• 2007

The anodic degradation of benzoquinone(BQ), a model compound for wastewater treatment was carried out using a home-made flow-through electrochemical cell with carbon fibers. To optimize the controlled current electrolysis condition of an aqueous BQ solution, the experimental variables affecting the degradation of BQ, such as the applying current, pH, reaction time, and flow rate of the BQ solution were examined. The degradation products of the oxidation reaction were identified by High Performance Liquid Chromatography and Inductively Coupled Plasma Atomic Emission Spectrometer. Low molecular weight aliphatic acids, and CO2 were the major products in this experiment. The removal efficiency of BQ from the solution increased with the applying current and time. 99.23% of 1.0 × 10-2 M BQ was degraded to aliphatic acids and CO2 when the applying current is 175 mA in a 12 hr electrolysis.