• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.67-74
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• 2002

A phosphor for Plasma Display Panel, BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$, showing a blue emission band at about 450nm was prepared by a solid-state reaction using BaCO$_3$, $Al_2$O$_3$, MgO, Eu$_2$O$_3$ as starting materials wish flux AlF$_3$. The study of the behaviour of Eu in BAM phosphor was carried out by the photoluminescence spectra and the Rietveld method with X-ray and neutron powder diffraction data to refine the structural parameters such as lattice constants, the valence state of Eu, the preferential site of Mg atom and the site fraction of each atom. The phenomenon of the concentration quenching was abound 2.25~2.3wt% of Eu due to a decrease in the critical distance for energy transfer of inter-atomic Eu. Through the combined Rietveld refinement, R-factor, R$_{wp}$, was 8.11%, and the occupancy of Eu and Mg was 0.0882 and 0.526 at critical concentration. The critical distance of Eu$^{2+}$ in BAM was 18.8$\AA$ at 2.25% Eu of the concentration quenching. Furthermore, c/a ratio was decreased to 3.0wt% and no more change was observed over that concentration. The maximum entropy electron density was found that the modeling of $\beta$-alumina structure in BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$correct coincided showing Ba, Eu, O atoms of z= 1/4 mirror plane.e.ane.e.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.343-349
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• 1991

Formation of charge transfer complex between iodine and substituted aniline [aniline, N,N-dimethylaniline(N,N-DMA), 2,6-dimethylaniline(2,6-DMA), 2,4,6-trimethylaniline(2,4,6-TMA)] in CHCl$_3$, CH$_2$Cl$_2$ : CHCl$_3$ (1 : 1), and CH$_2$Cl$_2$ have been studied kinetically by using conductivity method. In the transformation of initially formed outer charge transfer complex to inner complex, the effects of substituted aniline as electron donor and polar medium on the reaction were investigated. The rate of transformation depend on the dielectric contribution of medium and pK$_a$ value of substituted aniline. The order of rate increasing is 2,4,6-TMA, 2,6-DMA, aniline, and N,N-DMA. The activation enthalpy ${\Delta}H^{\neq}$ for 2.5 M-substituted aniline in CHCl$_3$ at 25$^{\circ}C$ is respectively N,N-DMA, 3.47 kcal/mol; aniline, 4.25 kcal/mol; 2,6-DMA, 7.79 kcal/mol and 2,4,6-TMA, 7.96 kcal/mol; and activation entropy ${\Delta}S^{\neq}$ is large and negative value of -41 ~ -55 cal/mol${\cdot}$K.

• Journal of Forest and Environmental Science
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• v.31 no.3
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• pp.207-213
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• 2015

It is estimated that there is a total of approximately 100,000 species in Korea. However, the number is currently about 30,000 and only 16,027 species are listed in the 'Species Korea' (as of December, 2014). Of the listed species, 51 species are designated as the Endangered Species Class I while 195 species are in the Class II, totaling 246 endangered species including 20 mammals. Under the circumstances that development (e.g., roads) is increasingly threatening the persistence of endangered mammals, it is significant to identify and preserve suitable habitats for them. In this context, evaluating the values of the suitable habitat environment would serve as essential information for development decision making. This study estimated the values of endangered mammals' forest habitats through spatialization of habitat services. In doing so, a species distribution model, Maximum Entropy Model (MaxEnt) was utilized for a group of endangered mammals including, mountain goat, wildcat, marten cat, and flying squirrel. To calculate the values per unit area, a benefit transfer method was used based on the point-estimate technique with the best available values estimated previously. The range of discount rate of 3.0 to 5.5 percent was applied taking the notion of social discount rate into account. As a result, the province with the highest values for endangered mammal habitats appeared to be Gangwon, followed by Gyeongbuk and Gyeongnam. The monetary values of the endangered mammal habitats were estimated to be 330 billion to 421 billion won per year.

• BMB Reports
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• v.45 no.8
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• pp.476-481
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• 2012

Flavodoxin (Fld) has been demonstrated to bind to ferredoxin-NADP$^+$ reductase A (FprA) in Pseudomonas putida. Two residues ($Phe^{256}$, $Lys^{259}$) of FprA are likely to be important for interacting with Fld based on homology modeling. Site-directed mutagenesis and pH-dependent enzyme kinetics were performed to further examine the role of these residues. The catalytic efficiencies of FprA-$Ala^{259}$ and FprA-$Asp^{259}$ proteins were two-fold lower than those of the wild-type FprA. Homology modeling also strongly suggested that these two residues are important for electron transfer. Thermodynamic properties such as entropy, enthalpy, and heat capacity changes of FprA-$Ala^{259}$ and FprA-$Asp^{259}$ were examined by isothermal titration calorimetry. We demonstrated, for the first time, that $Phe^{256}$ and $Lys^{259}$ are critical residues for the interaction between FprA and Fld. Van der Waals interactions and hydrogen bonding were also more important than ionic interactions for forming the FprA-Fld complex.

• Archives of design research
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• v.17 no.2
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• pp.67-76
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• 2004

The main stream of consumption about the products is tend to transfer from low price value with mass production, to the second value of products, such as pleasure, familiarity, humor, and metaphor. This second value is closely connected to a redundancy which are also related to modern science as well as product design. These terms such as matrials, identity, and gravitation, disappeared gradually, and these are substituted with an uncertainty principle, a fortuity, a contradictory concept, entropy etc. In sum this study focuses on the tendency of intelligency issue the recent design trends. This result shows that The 4th Column Thinking and Formation System which is related to an expansion and diversity of design intellectual ideas.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1260-1271
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• 2001

The simulation program which predicts the gas behavior in a spark ignition engine has been developed and verified by the comparison with the experimental results foy the MPI engine, naturally aspirated and turbochared engines with a carburettor. First paper describes the calculations of the behavior of gas in the intake and exhaust system. The generalized method of characteristics including friction, heat transfer, area change and entropy gradients was used to analyse the pipe flow The constant-Pressure model was applied for the analysis of the flow through engine valved, and the constant-pressure perfect-mixing model was applied for the flow at manifold junction. The concept of the sudden area change was used for the muffler and catalytic convertor. Fer the plenum chamber in an MPI engine, constant-pressure model and constant-volume model were both examined. Through the comparison of predicted results with experiments, the simulation program was verified by showing good prediction of the behavior of IC engine qualitatively and quantitatively under wide range of operating conditions.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3355-3360
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• 2011

The nucleophilic substitution reactions of 1,2-phenylene phosphorochloridate (1) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $-15.0^{\circ}C$. The studied substrate of 1,2-phenylene phosphorochloridate is cyclic five-membered ring of phosphorus ester, and the anilinolysis rate of 1 is much faster than its acyclic analogue (4: ethyl phenyl chlorophosphate) because of extremely small magnitude of the entropy of activation of 1 compared to 4. The Hammett and Bronsted plots exhibit biphasic concave upwards for substituent X variations in the nucleophiles with a break point at X = 3-Me. The values of deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) change from secondary inverse ($k_H/k_D$ < 1) with the strongly basic anilines to primary normal ($k_H/k_D$ > 1) with the weakly basic anilines. The secondary inverse with the strongly basic anilines and primary normal DKIEs with the weakly basic anilines are rationalized by the transition state (TS) variation from a predominant backside attack to a predominant frontside attack, in which the reaction mechanism is a concerted $S_N2$ pathway. The primary normal DKIEs are substantiated by a hydrogen bonded, four-center-type TS.

• Journal of Environmental Science International
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• v.22 no.9
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• pp.1161-1170
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• 2013

The efficiency of coal-based activated carbon in removing methylene blue (MB) and phenol from aqueous solution was investigated in batch experiments. The batch adsorption kinetics were described by applying pseudo-first-order, pseudo-second-order, and first order reversible reaction. The results showed that the adsorption of MB and phenol occurs complexed process including external mass transfer and intraparticle diffusion. The maximum adsorption capacity obtained from Langmuir isotherm was 461.0 mg/g for MB and 194.6 mg/g for phenol, respectively. The values of activation parameters such as free energy (${\Delta}G^0$), enthalpy (${\Delta}H^0$), and entropy (${\Delta}S^0$) were also determined as -19.0~-14.9 kJ/mol, 25.4 kJ/mol, and 135.2 J/mol K for MB and 51.8~54.1 kJ/mol, -29.0 kJ/mol, and -76.4 kJ/mol K for phenol, respectively. The MB adsorption was found to be endothermic and spontaneous process. However, the CV adsorption was found to be exothermic and non-spontaneous process.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.3
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• pp.139-148
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• 2016

Thermodynamic analysis is conducted on the first-order approximation model for turbines and compressors. It is shown that the adiabatic efficiency could be greater than unity, depending on the entropic mean temperature, entropy generation, thermal reservoir temperature, and heat transfer. Therefore, adiabatic efficiency applied to a diabatic control volume results in an error overestimating its performance. To resolve this overestimation, it is suggested that a reversible diabatic process be referred to as an ideal process to evaluate diabatic efficiency. The diabatic efficiency suggested in this work is proven to always be less than unity and it is smaller than the exergy efficiency in most cases. The diabatic efficiency could be used as a more general definition of efficiency, which would include adiabatic efficiency.

• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.4
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• pp.65-81
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• 2015

As research management is growing in importance for research organizations, their disciplinary structures need to be interpreted. However, it is not only difficult but ambiguous to detect causal relations between subjects because diverse disciplines interacting with each other lead the development of organizational research. Therefore, this article summarizes the major concepts and results recently achieved in the related fields such as research management, bibliographic analysis, information theory, and networks to characterize organizational knowledge structures. Relevant analytical methods obtained from the literature can be applied to empirical situations. Predictive causal relations can be measured using an information theoretic indicator on a series of organizational research portfolios identified from bibliographic information. A network approach would be suitable to manage organizational research effort from a holistic view. Knowledge structures of the Government-funded Research Institutes in Korea are explored experimentally.