• The Journal of Pediatrics of Korean Medicine
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• v.31 no.3
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• pp.14-23
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• 2017

Objectives This study is conducted to evaluate skin fat barrier formation of Hataedock using the Coptis japonica & Glycyrrhiza uralensis extract. Methods The 3-week-old NC/Nga mice were divided into 3 groups: control group (Ctrl), Hataedock-treated group that uses the Coptis japonica & Glycyrrhiza uralensis (CGT) extract, and Hataedock-treated group that uses Bifidobacterium (BBT). After 2 weeks, changes in immunohistochemicals, and skin-lipid-barrier regulators were observed for the effects of Hataedock. Results In CGT group, loricrin-positive reaction has been increased by 231%, along with involucrin-positive reaction by 90%, filaggrin-positive reaction by 143%, and ASM-positive reaction by 341% in the stratum corneum. Conclusions Hataedock, using the extract of Coptis japonica & Glycyrrhiza uralensis, increased the expression of proteins promoting keratinocyte differentiation. This leads into conclusion that Hataedock may increase the keratinocyte formation and function which promotes skin barrier formation.

• Journal of Environmental Science International
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• v.13 no.7
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• pp.667-674
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• 2004

The objective of this study was to investigate the effects of pH and temperature on the formation of bromate, which is ozonation by-products, during ozonation. In this experiment, the operating parameters including pH 3 ～ 10 and temperature 15 ～ $30^{\circ}C$ were studied. Through the study for the bromate formation, reaction rate constant, and ozonation effect index on pH and temperature, the results obtained are as follows. At the same initial pH condition, the increase of pH shown similar trends even if the reaction variables such as temperature and reaction time of ozonation were exchanged. As pH and temperature were increasing, the bromate concentration was increased but bromine(HOBr+OBr) was decreased with increasing pH from 3 to 10. The activation energy(J/mol) for bromate formation decreased with increasing pH. The rate constants of bromate formation for the reaction of ozone and bromide, and ozone dosage coefficient$(K_{0})$ increased with temperature and pH. Ozonation effect index(OI) decreased with increasing temperature and pH.

• Korean Journal of Materials Research
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• v.16 no.1
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• pp.50-57
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• 2006

Phase mixtures of Titanium boride, nitride, and carbide powder were produced by the reduction of a mixture of titanium and boron oxides with carbon via a gas-solid phase reaction. Boron oxides produce a vapour phase or decompose to a metal sub-oxide gaseous species when reduced at elevated temperature. The mechanism of BO sub-oxide gas formation from $B_2O_3$ and its subsequent reduction to titanium diboride for the production of uniform size hexagonal platelets is explained. These gaseous phases are critical for the formation of boride, nitride and carbide ceramics. For the production of ceramic phase composite microstructures, the nitrogen partial pressure was the most critical factor. Some calculated equilibrium phase fields has been verified experimentally. The theoretical approach therefore identifies conditions for the formation of phase mixtures. The thermodynamic and kinetic factors that govern the phase constituents are also discussed.

• Bulletin of the Korean Chemical Society
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• v.16 no.7
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• pp.609-613
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• 1995

The reaction of chloro(methylthio and arylthio)methanephosphonate (1) and Pummerer-type reaction of sulfinylmethanephosphonate (2) with nucleophiles such as aromatic compounds and thiols were examined. The direct chlorination of (methylthio and arylthio)methanephosphonate with N-chlorosuccinimide (NCS) led to the formation of monochlorinated phosphonates (1) in good yield. The reaction of 1 with aromatic compounds and thiols in the presence of stannic chloride afforded a variety of aryl(methylthio)methanephosphonates (3) and thioacetals of formylphosphonates (4), respectively. Phosphonates 3 and 4 were also obtained from the reaction of Pummerer intermediate, generated from sulfinylmethanephosphonate (2), with aromatic compounds and thiols, respectively. A versatile reaction conditions to generate Pummerer intermediate were examined. The best condition was the combination of trifluoroacetic anhydride with stannic chloride. All reactions may involve an initial formation of α-phosphoryl thiocarbocation and a subsequent nucleophilic attack of aromatic compounds and thiols.

• Journal of the Korean Chemical Society
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• v.23 no.2
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• pp.80-87
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• 1979

The active site for the formation of acrolein in propylene oxidation reaction over copper(Ⅱ)-exchanged zeolite Y has been studied. At the early stage of the reaction, the formation of hydrocarbons was observed. The formation of hydrocarbons decreased gradually during the course of reaction, apparently due to the poisoning the Bronsted acid sites. The formation of acrolein was quite low when the formation of hydrocarbons was proceeding. The formation of acrolein was depend on the copper ion content and this can be related to the availability of the copper ions inside the supercage. It seems that it is the copper ion not the Bronsted acid site which is primarily responsible for the formation of acrolein.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.905-910
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• 2006

In order to evaluate the optimum operation condition of ozonation to minimize bromate formation, based on the NOM characteristics of raw waters, the pathway of bromate formation by ozonation in domestic raw waters was investigated. Considering the bromate formation reactions, the fractions of bromate formation from bromide by OH radical and molecular ozone were calculated with measured values of ozone decay rate ($k_c$) and Rct. The results showed that molecular ozone is more important role in the formation of bromate in domestic raw waters than OH radical. The ratio of bromide oxidation reaction by molecular ozone ranged 73~88%. Fractions of $HOBr/OBr^-$ reaction with both molecular ozone and OH radical were also determined. OH radical reaction with $HOBr/OBr^-$ was dominant. The differential equations based on the stoichiometry of bromate formation were established to predict the formation rate of bromate by ozonation. The results shows good correlation with experimental results.

• Microbiology and Biotechnology Letters
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• v.22 no.3
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• pp.283-289
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• 1994

The production of maltose utilizing swollen extrusion starch seems to have many technical advantages, such as, high reaction rate and high yield, production of high purity concentrated maltose, and low energy consumption, over the conventional method utilizing liquefied starch. The characteristics of maltose formation in heterogeneous enzyme reaction system comtaining swollen extrusion starch was investigated using fungal $\alpha $-amylase. The influence of extrusion conditions on structure of extruded starch, such as, degree of gelatinization, water absorption index, and water solubility index was analyzed. The relationship between the structural features and maltose forming reaction was investigated, and the result was analyzed in terms of surface reaction of insoluble extruded swollen starch. The characteristics of maltose formation from swollen sxtrusion starch was compared using endo-type fungal $\alpha $-amylase and exo-type $\beta $anylase, and the structural trasformation of extruded starch was also observed to clarify the reaction mechanism.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.360-367
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• 1997

The chemistry background of the Maillard reaction focused on pyrazines and factors affecting the reaction products were reviewed. The Maillard reaction, also called a non-enzymatic browning reaction, is quite complex and generates numerous reaction products. In processed foods, it is generally accepted as a key reaction to produce flavor components. Specially, pyrazines possess an important impact character on the roasted foods with other heterocyclic compounds. The Maillard reaction is initiated by condensation between reducing sugar and amino group, and N-glycosylamines are produced via Schiff base with dehydration of water. After the rearrangement of the N-glycosylamines, they follow transformation into deoxyhexosones which are reactive intermediates. Degradation and fragmentation are facilitated by rearranged compounds. By condensation, pyrazine, one of the final Maillard products, is generated as a relatively stable form to provide specific aromas. During the processes of the reaction, chemical or physical environmental parameters affect the formation of the products.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.291-296
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• 2018

Direct synthesis of methylchlorosilanes was developed by Rochow with addition of copper on the silicon surface as a catalyst and many research were followed. Most of research were focused on the increase of reaction activity through addition of promoters and concentrated on the increase of selectivity of DMDC. However, there are very few studies about the reaction mechanism. Although formation of DMDC was explained in literature, formation of other silanes were not mentioned at all. This reseach focused on the explanation about formation of all silanes obtained during direct reaction and TPD. Reaction paths were proposed by means of dissociative adsorption of methyl chloride and spillover of surface Cl and H. Surface silicon sites were considered as $=SlCl_2$ and $=Sl(CH_3)Cl$. The synthesis of all methylchlorosilanes were explained by the adsorption of methyl group on the silicon sites and by the surface diffusion of nearby Cl and H. The proposed reaction mechanism explains the formation of all silanes during the reaction and also during the TPD process.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.145-150
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• 2004

This study investigated the effect of chlorine dose and chlorine reaction time for the formation of haloacetic acids (HAAs). According to the results, HAA formation was highly affected by chlorine dose and chlorine reaction time. HAA formation reached a plateau value at 30 mg/L of chlorine dose and 24 hr of chlorine reaction time. For the speciation of formed HAAs in the test water, the concentration of brominated-HAAs was significantly lower than that of chlorinated-HAAs because of low level of bromide ion concentration in the test water. It also investigated the removal efficiency of HAA precursors by several unit processes, such as ozone alone, UV alone, and combined ozone/UV system. Of them, ozone/UV system was proved as the best process to control the HAAs formation. The increase of the brominated-HAAs was observed during ozonation with and without UV irradiation showing the slight increase of total HAA concentrations.