• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.424-433
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• 2015

The operating characteristics of hydrogen iodide (HI) decomposition for hydrogen production were investigated using the commercial computational fluid dynamics code, and various factors, such as hydrogen production, heat of reaction, and temperature distribution, were studied to compare device performance with that expected for device development. Hydrogen production increased with an increase of the surface-to-volume (STV) ratio. With an increase of hydrogen production, the reaction heat increased. The internal pressure and velocity of the HI decomposer were estimated through pressure drop and reducing velocity from the preheating zone. The mass of $H_2O$ was independent of the STV ratio, whereas that of HI decreased with increasing STV ratio.

• Journal of Korean Society on Water Environment
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• v.18 no.3
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• pp.271-282
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• 2002

The sonochemical process has been applied as a treatment method to investigate its effect on the decomposition of humic substances (HS). The reaction kinetics and mechanisms in the process of sonochemical treatment for humic substances in wastewater have also been discussed. It was observed that the metal ions such Fe(II) and Mn(II) showed catalytic effects, while Al(III), Ca(II), and Mg(II) had inhibitory effects on the decomposition of humic substances in sonochemical reaction with hydrogen peroxide. Experimental results also showed factors such as hydrogen peroxide dose affected the formation of disinfection by-products. Two trihalomethanes, chloroform and dichlorobromomethane were formed as major disinfection by-products during chlorination. The depolymerization and the radical reaction of HS radicals appear to occur simultaneously. The final step of the reaction is the conversion of organic acids to carbon dioxide.

• YAKHAK HOEJI
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• v.15 no.1
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• pp.32-40
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• 1971

Optimum reactons for the preparation of extra-light magnesium carbonate from magnesium chloride and sodium carbonate solutions were found by observing the difference of crystalline shapes under an electromicroscope. Reaction temperature the and washing temperature were main factors affecting the crystalline shapes, and drying temperature was found to be of secondary importance. Optimum temperatures for reaction and washing ranged from $20^{\circ}C$ to $30^{\circ}C$ and the temperature over $40^{\circ}C$ should be avoided for the reaction and washing. It was found that the higher the drying temperature, the lighter the crsytal of the produced magnesium carbonate. Reaction time, molar ratio (Mg$^{2+}/CO_{3}^{2-}$ ) and the concentrations of magnesium chloride and sodium carbonate solutions have only a slight effect on the form of the product.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.1
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• pp.11-25
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• 2024

Lithium-ion batteries (LIBs) have attracted great attention as the common power source in energy storage fields of large-scale applications such as electrical vehicles (EVs), industries, power plants, and grid-scale energy storage systems (ESSs). Insertion, alloying, and conversion reactions are the main electrochemical energy storage mechanisms in LIBs, which determine their electrochemical properties and performances. The electrochemical reaction mechanisms are determined by several factors including crystal structure, components, and composition of electrode materials. This article reviews a new strategy to compensate for the intrinsic shortcomings of each reaction mechanism by introducing the material systems to form a single compound with different types of reaction mechanisms and to allow the simultaneous hybrid electrochemical reaction of two different mechanisms in a single solid solution phase.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.670-679
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• 2011

This study investigated the hotel buffet restaurant's service quality, emotional reaction of customer, recommendation intention, and defection intention. The survey was conducted from January 3 to February 7 in 2011, and 400 respondents were used in the data analysis. As a results of this study, the hotel buffet restaurant's service quality was classified by the interaction, outcome, and physical environment quality. The emotional reaction of hotel buffet restaurant's customer was classified by the positive and negative emotion. The all factors of hotel buffet restaurant's service quality had a positive impact on positive emotion, while it had a negative impact on negative emotion. The positive emotion reaction of hotel buffet restaurant's customer had a positive impact on the recommendation intention, while the negative emotion had a negative impact on the recommendation intention. And the negative emotion had a positive impact on the defection intention in hotel buffet restaurants. In addition, there were partially differences in the service quality and emotional reaction by general characteristics. There were significant differences in the recommendation intention by marriage status and monthly income. Therefore, the hotel buffet restaurants have to design a strategy of service for increasing customer's positive emotion and recommendation intention.

• Journal of the Korean Society of Combustion
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• v.21 no.4
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• pp.23-29
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• 2016

Reactivity of gasification defined by bouardard reaction is critical parameter in efficiency of the gasifier. In this study, char reactivity of the gasification was derived from the experiments using the intrinsic reaction kinetics model. Pressurized wire mesh heating reactor (PWMR) can produce high temperature and high pressure conditions up to 50 atm and 1750 K, respectively and PWMR was designed to evaluate the intrinsic reaction kinetics of $CO_2$ gasification. In this study, Kideco and KCH (sub-bituminous Indonesian coal) were pulverized and converted into char. Experiments used the PWMR were conducted and the conditions of the temperature and pressure were 1373~1673 K, 1~40 atm. To distinguish the pressure effect from high pressurized condition, internal and external effectiveness factors were considered. Finally, the intrinsic kinetics of the Kideco and KCH coal char were derived from $n^{th}$ order reaction rate equations.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1349-1351
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• 2008

This study examined the effects of temperature, D-psicose concentration, pH, and various amino acids on the Maillard browning reaction of D-psicose and glycine mixture and compared browning color intensity with those of other sugars, such as sucrose, D-glucose, D-fructose, and D-tagatose. When D-psicose (0.1 M) and glycine (0.1 M) mixture was heated at $70-100^{\circ}C$ for 5 hr, the absorbance at 420 nm increased with increasing reaction temperature and time. The Hunter a, b values, and color difference (${\Delta}E$) increased with increasing D-psicose concentration and pH within the range of pH 3-7 except at pH 6, while the L value decreased. The rate of Maillard browning reaction was in order of D-tagatose>D-psicose $\fallingdotseq$ D-fructose>D-glucose>sucrose. The browning color intensity of the D-psicose-basic and non-polar amino acids mixtures was higher than that of the D-psicose-acidic amino acids.

• Archives of design research
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• v.13 no.3
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• pp.7-16
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• 2000

Aesthetics undertakes important roll in design as a competitive factor. The importance of aesthetics can be found in experimental aesthetics, Gestalt psychology and design related literatures. These literatures suggest that, besides the importance of aesthetics, many other aesthetic factors would affect consumer reaction(recognition, emotional reaction, meaning), but the study is still in insufficient condition. Hense, this study tries to give a guideline -'how to design symbols'based on the apprehension of what kind of design is well recognized(correct recognition), gives positive emotional reaction(affect) to customers, and moreover, what sort of aesthetic factors affect these reactions by analyzing existing symbol designs.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.44-50
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• 2001

This study was carried out to investigate characteristics of water quality and THMs formation in lake-waters at kunsan. Of the parameters examined for water quality, pH, alkalinity, SO$_4$$^{-2}$ and Co- reflected the characteristics according to the origin, geography and water source of lakes while COD, SS, T-P, T-N and chlorophyll-a corelatively reflected well the influence of pollution factors around factors around lakes. The result of water quality analysis showed that most lakes in Kunsan area have the severe eutropnication problem, especially in summer. In lake-waters, THMFP overally continued to increase until 48 hour with the reaction time and THMs formation was largely achieved within 24 hour of the reaction time. The average formation ratio were 68.2% for CHCl$_3$, 23.6% for CHCl$_2$Br, 7.6% for CHClBr$_3$ and 0.6% for CHBr$_3$respectively and much difference depending on the reaction time was not shown. Overally, 96h-THEFP levels in lakes were high during June~September and showed higher tencency in lakes where could be regarded more contaminated on the whole. These results suggest that THMFP may be available for the management of lake-water quality as one if the useful parameters for the general evaluation of contamination. 96h-THEMFP failed to show the strong corelation individually with pH, TOC, COD and chlorphyll-a.

• Korean Journal of Materials Research
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• v.15 no.6
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• pp.419-425
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• 2005

In this paper, we describe the luminescent properties of the phosphors synthesized via sol-gel technique. When the phosphor prepared by sol-gel technique, reaction factors, such as pH condition, $R_w$ and drying temperature affected the luminescent intensity, particle size and morphology of final product. Therefore, we attempt to control these reaction factors in order to improve the luminescent efficiency of phosphors. As a result of our study, when the acid catalyst (HCl) was used, emission intensity was higher than the case of base catalyst $(NH_4OH)$. The product prepared at $R_w=60$ indicated the maximum intensity. As the increase of the $R_w$ value, the particle was agglomerated and emission intensity was decreased. Finally, optimum drying temperature of gel was found to be$ 180^{\circ}C$.