• 한국주조공학회지
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• 제5권4호
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• pp.271-282
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• 1985

In order to investigate the mold reaction characteristics of Mn steel and Cr steel castings individually, the mold reaction products were examined by scanning electron microscopy, electron prove microanalyzer and X-ray diffractometer. From this experiment, the results were summarized as follows: 1) The mold reaction depth increased with increase of Mn content, while it decreased with increase of Cr content. 2) Mold reaction depth decreased with Mn content at $1200^{\circ}C$. 3) Mn, among the reaction products, forms a low fusion silicate, Mn $O.SiO_2$ while Cr forms a stable oxide, $CrO_3$ which hindering the reaction between FeO and $SiO_2$ thus the formation of $FeO.SiO_2$ was depressed.

• 한국응용과학기술학회지
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• 제12권2호
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• pp.145-150
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• 1995

The Kinetics velocity for hydrolysis reaction of vanillylidene imine derivatives has been measured by ultra-violet ray spectrophotometer in 20wt% $dioxane-H_2O$ at $25^{\circ}C$. It was measured the reaction rate Constant of vanillylidene imine derivatives that can be applied widely following to pH-change at $25^{\circ}C$. Final products that hydrolyzed the vanillylidene imine certified in vanillin and aniline derivative, and the effect of substitution radical that has affected on hydrolysis reaction was largely promoted to reaction rate by electron attrating group in acidity and electron donoring group in basic. From the results of rate constant to hydrolysis reaction, substituent radical effect and final products. It has certified the hydrolysis reaction mechanism of vanillylidene imine derivatives.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1681-1688
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• 2010

Density functional theory was adopted to study the various surface products and their reaction channels focusing on the on-dimer configuration which has not been suggested before. Energetic results show that the most stable on-dimer configuration is the 6,6-[2+2] structure which resembles the typical [2+2] cycloaddition product. The 6,6-[2+2] product is also more stable than any other possible surface structures of inter-dimer configuration further suggesting its existence. Potential energy surface scan along various possible initial surface reactions show that some of the possible on-dimer surface products require virtually no reaction barrier indicating that initial population of on-dimer surface products is thermodynamically determined. Various surface isomerization reaction channels exist further facilitating thermal redistribution of the initial surface products.

• 한국식품영양과학회지
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• 제23권5호
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• pp.867-878
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• 1994

A general overview of the lipid peroxidation and its nutritional significance are presented ,with emphasis on the reaction mechaisms, peroxidized products, further interaction and nutritional/biological deterioration in a series of oxidative process. Overall mechanism with various factors and elements for initiation , propagation and termination of free radical reaction is reviewed and the primary /secondary products of peroxidized lipids are defined. Since these products are potentially reactive substances that can cause deterioration of proteins /amino acids and vitamins (carotene, tocopherols and ascorbic acid etc), mechanism and actual damages of their deterioration in some foods and biological models are outlined. Especially , chemical changes caused by interaction of peroxidized products (related hydroperoxides, radicals and malonaldehye etc) and protein are emphasized here. And also, the detailed mechanisms on radical scavenging of the these vitamins which are the most prominent natural antioxidants are presented . Additionally , the possible roles of peroxidicaed lipids and their secondary products in the process of aging an carcinogenesis are briefly discussed . However, it is important to not that more detailed and integrated studies on the reaction kinetics, energetics of peroxidation, their decomposed products , biochemical interaction potential damaging/aging / carcinogenic effects, protection from their oxidative spoilage and novel antioxidants in food and heterogeneous biological systems will be essential in order to assessing the implication of lipid peroxidation to human nutrition and health.

• Fisheries and Aquatic Sciences
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• 제11권3호
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• pp.133-139
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• 2008

Molecular techniques, including restriction fragment length polymorphism(RFLP) and polymerase chain reaction-single strand conformational polymorph isms(PCR-SSCP), were developed to identify salted, dried threadfin(Eleutheronema tetradactylum) and white herring(Ilisha elongata) fish. Using PCR with universal primers, conserved 367-bp fragments of the cytochrome b gene were amplified from fresh fish samples and sequenced. The sequences were then searched for specific restriction sites. The digestion of the PCR products with the endonucleases AvaI, FokI, MboII, and MspI generated RFLP, which was used to identify the commercial products. Similarly, the amplified PCR-SSCP products were developed and the products tested. Overall, similar patterns were found in the majority of the fresh and processed products. Based on the results, both RFLP and PCR-SSCP were useful in determining and validating the authenticity of the fish species used to prepare the commercial salted, dried products. A similar approach can be applied to other species.

• Journal of Photoscience
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• 제4권1호
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• pp.17-21
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• 1997

The photochemical reactions of the neat chloroform and the aqueous chloroform in the absence (saturated with argon) and presence of 02 (saturated with air or oxygen) have been investigated using 184.9 nm UV light. The irradiation of the deoxygenated neat chloroform causes the formation of hexachloroethane, pentachloroethane, and 1, 1, 2, 2-tetrachloroethane. The initial quantum yields of the products were determined to be 6.37 x 10$^{-4}$, 4.04 x 10$^{-4}$ and 1.76 x 10$^{-4}$, respectively. In the irradiation of aqueous chloroform, chloride ion was also formed along with the products listed above and 1, 1, 2, 2-tetrachloroethane was the predominant product among the chlorinated organic products, which contrasts to the case of the neat chloroform. The presence of oxygen during the irradiation of aqueous chloroform had an effect on the yield of the products. With increasing the concentration of oxygen, the formation of the products was decreased. Probable reaction mechanisms for the photochemical reaction were presented on the basis of products analysis.

• 한국분말재료학회지
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• 제2권2호
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• pp.158-164
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• 1995

Synthesis of the NiTi shape memory alloy using the thermal explosion mode of the self-propagating high-temperature synthesis has been investigated. The significant fractions of intermetallics phases were found to form at the Ti/Ni powder interface during the heating to the ignition temperature and seemed to influence the relative fraction of phases in the final products. As the heating rate to the ignition temperature was increased, the combustion temperature and the fraction of NiTi in the final reaction products were increased. The synthesis reaction under 70 MPa compressive pressure yielded a reaction product with 98% theoretical density.

• Bulletin of the Korean Chemical Society
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• 제20권4호
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• pp.441-444
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• 1999

The alkyl Grignard addition reaction on 1-benzyltetrazolylimine proceeds to give N-alkylated products (azophilic addition) and, in contrast, the same reaction on 2-benzyltetrazolylimine produced predominantly C-alkylated products (carbophilic addition). In this report we described theoretical explanations for this experimental finding on the basis of the frontier molecular orbitals and the electrostatic nature of the reactants and the reaction intermediates.

• Bulletin of the Korean Chemical Society
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• 제17권4호
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• pp.334-338
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• 1996

Tetra-chlorodibenzo-p-dioxins (tetra-CDDs) were prepared by microscale pyrolysis of trichlorophenates. During the pyrolysis reaction, tri-, di-, and mono-CDDs were also formed by the thermolysis of tetra-CDDs. The dechlorination pathways of tetra-CDDs were suggested for this reaction. The identification of these products was performed with capillary column gas chromatography-mass spectrometry.

• 한국수산과학회지
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• 제20권1호
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• pp.52-56
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• 1987

The antioxidative activity of each molecular weight (MW) fraction of Maillard reaction products prepared from a D-glucose and glycine system, i. e., MW below 1000, MW between 1000 to 3000 and MW above 5000, nondialyzable melanoidins, reduced melanoidins and ozone-treated melanoidins were estimated in a linoleic acid-aqueous system. The antioxidative activity ana reducing ability of Maillard reaction products increased with increasing molecular weight and color intensity. Maillard reaction products of MW above 1000 showed obvious antioxidative activity and reducing ability, whereas the MW fraction below 1000 showed only weak activities. When nondialyzable melanoidins were reduced with sodium borohydride, their color intensity and reducing ability remarkably decreased, but their antioxidative activity did not decrease so much.