• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.738-741
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• 2001

We carried out aminolyses of various rigid polyurethane foams (PUFs) using diethylene triamine and studied application of the aminolysis products as hardners of epoxy resins. Diglycidyl ether of bisphenol A was used for the study on the curing behavior of epoxy resin with the aminolysis product employing differential scanning calorimeter. Curing reaction of the epoxy resin is generally known to be autocatalytic second order reaction. We found that the curing reaction of the epoxy resin with the aminolysis product of rigid PUF did not show autocatalytic characteristics but followed the n-th order kinetics. The activation energy of the curing reaction of the epoxy resin with the aminolysis product of rigid PUF made from sugar based polyol was slightly lower than that of the epoxy resin with aminolysis product of rigid with made from amine based polyol.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1233-1236
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• 2010

2,3-Dichloro-1,4-naphtoquinone 1 compound was reacted with octadecanethiol 2 in two different mole ratio. Compound 3 was obtained from the reaction of 1 and 2 in 1:2 mole/mole ratio. Compounds 7 and 8 were obtained from reaction of 1 and 2 in 1:1 mole/mole ratio and known compound 9 was synthesized as by-product in this reaction. Novel compounds 5a-e were obtained from reaction of 1 and related thiols 4a-e. Known compounds 6c and 6e were synthesized as by-product in this reaction. The structures of the compounds were characterized by elemental analysis, UV-vis, FTIR, $^1H$-NMR, $^{13}C$-NMR and Mass spectroscopies.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.14 no.2
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• pp.17-22
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• 2003

Although researchers have, during the past decade, become increasingly interested in customer satisfaction customer reaction, and service quality issues, very little of research has devoted to the family restaurant. Family restaurant industry is among the fastest growing sectors of the tourism market. This paper discusses the importance of the family restaurant product and service quality, and presents the relationship among service quality, customer satisfaction, and customer reaction. The literature supports the value of family restaurant's service quality and relation between service quality and customer reaction. Exploratory study examined customer's satisfaction with service quality components and customer's reaction with satisfaction. The survey was conducted in four phases; service quality, customer reaction(satisfaction, repurchase intention, and word of mouth), restaurant information, general profile of customer. The results of the study show that service quality(product's quality, physical character) provided family restaurant customer with the overall satisfaction, and service quality affected on customer reaction(repurchase intention, positive word of mouth). Also overall satisfaction affected on repurchase intention and positive word of mouth.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.869-876
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• 1990

Hexagonal boron nitride was synthesized from boron oxide and sodium amide in ammonia gas stream. The reaction mechanisms and characteristics of as synthesized boron nitride was investigated by means of TG, DTA, IR, XRD, SEM and PSA. The results are ; 1) hexagonal boron nitride was synthesized from reactions at temperatures above 40$0^{\circ}C$ 2) Sodium metaborate was present as by-product after reaction so that the reaction mechanism is reduced as follows : 2B2O3＋3NaNH2longrightarrowBN＋3NaBO2＋2NH3. 3) boron nitride obtained at the reaction temperature below 40$0^{\circ}C$ is found to have random layer strudcture but the structure transits to ordered layer structure rapidly with increasing reaction temperature, showing separation of (101) differaction line from (10)band in XRD pattern of the reaction product at 50$0^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.13-19
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• 1989

Two different quartz types of gasification reactor were used for pyrolysis and gasification of sawdust, ricestraw, ricehusk and municipal wastes which contain only cellulosics., operating at 1 atmospheric and vacuum pressure respectively. Also a stainless steel autoclave gasification reactor was used which is possible to use up to 100 atmospheric pressures and $800^{\circ}C$ of reaction temperature to complete pyrolysis and gasification reaction. The catalysts used in this reaction w- ere $K_2CO_3$, $Na_2CO_3$, Ni and Ni-$K_2CO_3$ as CO-Catalyst. The product gas mixtures were identified to be CO, $CO_2$, $C_3H_3$, $CH_4$ and $CH_3CHO$ etc. by Gas Chromatography and Mass Spectrometry. The pressurized gasification reaction shows significant increase in terms of methane composition and yield of product gases, comparing with those from unpressurized gasification reactions. The total volume of product gas mixtures amounts to 1600-1800ml per1gof waste of waste lignocellulosics or municipal waste, and the metane content of the gas mixtures reached to 40%, when $800^{\circ}C$ of reaction temperature and 100 atmospheric pressures with Ni-$K_2CO_3$ as CO-catalyst in the pressurized gasification reaction were used. This results show that the product gas mixtures containing 40% of methane call be used for alternative enegy source.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.573-576
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• 2016

In this study, hydrogenation of 1,2,3,3,3-pentafluoropropene was performed to produce R-1234yf as an environmentally friendly refrigerant. Palladium based carbon was prepared as a catalyst in the hydrogenation reaction. The effect of reaction conditions including the weight hourly space velocity (WHSV), reaction temperature and ratio of hydrogen and reactants on the catalytic performance was investigated. Under the identical reaction conditions, the effect of WHSV on the main product selectivity was insignificant, but a high reaction temperature was essential for the good product selectivity. A high product selectivity was also obtained when the ratio of hydrogen and reactants kept less than 1.5. Moreover, a correlation model involving the statistical approach to predict product yields was developed.

• International Journal of Concrete Structures and Materials
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• v.1 no.1
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• pp.75-81
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• 2007

The concrete pavement of the Seohae Highway in Korea has suffered from serious distress, only four to seven years after construction. Deterioration due to Alkali-Silica Reaction (ASR) has seldom been reported per se in Korea, because the aggregate used for the cement concrete has been considered safe against alkali-silica reaction so far. The purpose of this study is to examine the deterioration caused by an alkali-silica reaction of concrete pavement in Korea. The investigation methods included visual inspection and Automatic Road Analyzer (ARAN) analysis of surface cracks, coring for internal cracks, stereo microscopic analysis, scanning electronic microscope (SEM) analysis, and electron dispersive X-ray spectrometer (EDX) analysis. The results are presented as follows: the crack pattern of the concrete pavement in Korea was longitudinal cracking, map cracking or D-cracking. Local areas of damage were noticed four to five years after construction. The cracks started from edges or joints and spread out to slabs. The most intensive cracking was observed at the intersection of the transverse and longitudinal joints. Where cracking was the most intense, pieces of concrete and aggregate had spalled away from top surface and joint interface area. The progress of deterioration was very fast. The reaction product of alkali-silica gel was clearly identified by its generally colorless, white, or very pale yellow hue seen through a stereo optical microscopy. The typical locations of the reaction product were at the interface between aggregate and cement paste in a shape of a rim, within aggregate particles in the cracks, and in the large void in the cement paste. Most of the white products were found at interface or internal aggregates. SEM and EDX analysis confirmed that the white gel was a typical reaction product of ASR. The ASR gel in Korea mainly consisted of Silicate (Si) and Potassium (K) from the cement. The crack in the concrete pavement was caused by ASR. It seems that Korea is no longer safe from alkali-silica reaction.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.145-150
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• 2018

A new methodology, the crack-spallation model, has been developed to analyze gas-solid reactions dominated by crack growth inside of the solid reactant and spallation phenomena. The new model physically represents three processes of the reaction progress: (1) diffusion of gas reactant through pores; (2) growth of product particle in pores; and (3) crack and spallation of solid reactant. The validation of this method has been conducted by comparison of results obtained in an experiment for oxidation of $UO_2$ and the shrinking core model. The reaction progress evaluated by the crack-spallation model shows better agreement with the experimental data than that evaluated by the shrinking core model. To understand the trigger point during the reaction progress, a detailed analysis has been conducted. A parametric study also has been performed to determine mass diffusivities of the gas reactant and volume increase constants of the product particles. This method can be appropriately applied to the gas-solid reaction based on the crack and spallation phenomena such as the voloxidation process.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.179-182
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• 1996

Hydrodediazoniation product (3a-d) was found to be the major product in the reaction of arenediazonium tetrafluoroborate (1a-d) with triethylamine (2) in methanol under nitrogen at room temperature. A quantitative study on the title reaction was investigated in detail and two remarks were noteworthy. One was the linear increase in the yield of 3a-d by increasing the molar concentration of 2 until equimolar concentration was reached between 1a-d and 2. The other was the suppression of the formation of 3a-d in the presence of oxygen. Based on these results, the title reaction was better understood by 1:1 electron transfer reaction between reactants (1a-d and 2) rather than by radical chain mechanism proposed in the reaction of arenediazonium tetrafluoroborate and triphenylphosphine.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2968-2972
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• 2013

A highly efficient and environmentally benign protocol has been developed for the first time to produce a wide range of biologically active 5-hydroxyindole derivatives using montmorillonite KSF clay as a reusable solid acid catalyst. The use of recyclable clay makes this procedure quite simple, more convenient and cost-effective.