• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.943-951
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• 1990

Steady-state sublimation vapour pressures of anhydrous bismuth triiodide have been measured by the continuous gravimetric Kundsen-effusion method from 430.0 to 558.9 K and equilibrium sublimation pressures were obtained from the steady-state data. Condensation coefficients and their temperature dependence have been derived from the effusiion measurement. Condensation coefficients ranged from 0.159 to 0.048(475 to 500K), the activation enthalpy and entropy for condensation have been obtained as -93.38kTmol-1 and -212.70JK-1mol-1. The standard sublimation enthalpy changes derived by both second(modified sigma function) and third(average enthalpy method) law methods were 138.261$\pm$0.023, 138.74$\pm$0.002kJmol-1 respectively. The standard sublimation entropy change derived by modified sigma function was 191.98$\pm$0.047 JK-1mol-1. The reliable standard sublimation enthalpy change based on a correlation of ΔgcrHom(298.15K) and ΔgcrSom(298.15K), a recommended p(T) equation has been obtained for BiI3(cr) ; 1g(p/Pa)=-C/(T/K)＋5.0711g(T/K)-2.838$\times$10-3(T/K)-7.758$\times$103(K/T)2＋1.4519 where p is in Pa, T in Kelvin, ΔgcrHom(298.15K) in kJmol-1 and C=(ΔgcrHom(298.15K)-8.7358)/1.9146$\times$10-2.

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.40-46
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• 1995

In order to study the dyeability of wool S-cyano ethylated wool-keratine(SCEK) as a model compound of wool was prepared from the reaction of reduced merino wool fiber and acrylonitrile. The binding of acid dyes(methyl orange and it's homologs) by SCEK over the temperature 60~9$0^{\circ}C$ were investigated. The first binding constants and the thermodynamic parameters in the course of the binding were evaluated. It was found that at the 60~9$0^{\circ}C$ range complex formation between the dye and SCEK is associated with an exothermic enthalpy change and a positive entropy change. The enthalpy and entropy changes of the binding are of the order of -4.5 kcal/mole and 8.5 eu, respectively, for each dye measured. Thus the binding is mainly enthalpy-controlled. Furthermore the effect of the alkyl chain length of the dye on both the ΔH$^{\circ}$and ΔS$^{\circ}$value is not prounced. Also temperature dependences of the ΔH$^{\circ}$and ΔS$^{\circ}$values were not obserbed.

• Journal of Magnetics
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• v.16 no.4
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• pp.440-443
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• 2011

In this study, we investigated the glass-forming ability (GFA) and magnetocaloric effect (MCE) of $Gd_{55}Co_{20}Al_{23}Si_2$ bulk glassy alloy. It is found that the addition of 2 at% Si is effective for extension of the supercooled liquid region (${\Delta}T_x$), the ${\Delta}T_x$ is 55 K for the $Gd_{55}Co_{20}Al_{25}$ glassy alloy, and increases to 79 K for the $Gd_{55}Co_{20}Al_{23}Si_2$ alloy. As a result, $Gd_{55}Co_{20}Al_{23}Si_2$ glassy alloys with diameters up to 5 mm were successfully synthesized. The alloys also exhibit large MCE, i.e., the magnetic entropy change (${\Delta}S_m$) of 8.9 J $kg^{-1}\;K^{-1}$, the full width at half maximum of the ${\Delta}S_m$ (${\delta}T_{FWHM}$) of 87 K, and the refrigerant capacity (RC) of 774 J $kg^{-1}$.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.1
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• pp.47-53
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• 2022

The escape behavior of prey fish to predator attack is directly linked to the survival of the fish. In this study, I explored the escape behavior of Medaka fish to bird attacks. To simulate the attack, I designed a model triangular-shaped bird to slide along a fishing line connected between rods at both ends of the tank. The triangular shape was set to 10×15 (S=1), 15×20 (S=2), and 20×25 cm (S=3) with base×height. The slope (θ) of the fishing line, which determines the attack speed of the model bird, was set to values of 15° (θ=1), 30° (θ=2), and 45° (θ=3). The escape behavior was characterized using five variables: escape speed (ν), escape acceleration (α), responsiveness (γ), branch length similarity entropy (ε), and alignment (ϕ). The experimental results showed when (S, θ)=(fixed, varied), the change in values of the five variables were not significant. Thus, the fish respond more sensitively to S than to θ In contrast, when (S, θ)=(varied, fixed), ν, α, and γ showed increasing trends but ε and ϕ did not change much. This indicates the nature of fish escape behavior irrespective of the threat is inherent in ε and ϕ. I found that fish escape behavior can be divided into two types for the five physical quantities. In particular, the analysis showed that the type was mainly determined by the size of the model bird.

• Steel and Composite Structures
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• v.19 no.3
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• pp.569-583
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• 2015

Recent years, explosive welding structures have been widely used in many engineering fields. The bonding state detection of explosive welding structures is significant to prevent unscheduled failures and even catastrophic accidents. However, this task still faces challenges due to the complexity of the bonding interface. In this paper, a new method called dual-tree complex wavelet transform based permutation entropy (DTCWT-PE) is proposed to detect bonding state of such structures. Benefiting from the complex analytical wavelet function, the dual-tree complex wavelet transform (DTCWT) has better shift invariance and reduced spectral aliasing compared with the traditional wavelet transform. All those characters are good for characterizing the vibration response signals. Furthermore, as a statistical measure, permutation entropy (PE) quantifies the complexity of non-stationary signals through phase space reconstruction, and thus it can be used as a viable tool to detect the change of bonding state. In order to more accurate identification and detection of bonding state, PE values derived from DTCWT coefficients are proposed to extract the state information from the vibration response signal of explosive welding structure, and then the extracted PE values serve as input vectors of support vector machine (SVM) to identify the bonding state of the structure. The experiments on bonding state detection of explosive welding pipes are presented to illustrate the feasibility and effectiveness of the proposed method.

• Journal of the Korean housing association
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• v.11 no.3
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• pp.125-136
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• 2000

The purpose of this study was to analyze water consumption in each apartment buildings influenced by several factors that are the income level of inhabitants, life style, the area apartments and climate. The automation of sanitary machines or facilities in recently built apartments has caused largely increases in amount of water consumption. Therefore, the design for water supply is very important for the maintenance of the optimum level or pressure of water supply. This study is based on the offer of basic data for improving the quality of water supply and employing the sanitary machines or sanitary facilities by analysis of amount increased of water consumption rapidly. Amount of water consumption data, the change in quality of entropy to the supply water pipe was analyzed and presented to indicate the necessary to basic materials for the design of an optimal water pipe.

• Korean Journal of Remote Sensing
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• v.34 no.1
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• pp.117-126
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• 2018

This study aims to evaluate the usability of polarimetric SAR measurements for discriminating water-covered area from other land cover types and to propose polarimetric parameters showing the better response to the flood. Flood-related changes in the polarimetric parameters were studied using the L-band PALSAR-2 quad-pol mode data acquired before and after the severe flood events occurred in Joso city, Japan. The experimental results showed that, among various polarimetric parameters, the HH-polarization intensity, the Shannon entropy, and the surfaces scattering component of model-based decomposition were found to be useful to discriminate water-covered areas from other land cover types. Particularly, an unsupervised change detection with the Shannon entropy provides the best result for an automated mapping of flood extents.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.11
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• pp.3022-3030
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• 1995

The irreversibility of condensation process in the supersonic flow of steam turbine cascade causes the entropy to increase and the total pressure loss to be generated. In the present study, in order to investigate the moist air flow in two dimensional steam turbine cascade made as the configuration of the last stage tip section of the actual steam turbine moving blade, the static and total pressures along suction side of the blade are measured by pressure taps and Pitot tube. The flow field is visualized by a Schlieren system. The effects of stagnation temperature and the degree of supersaturation on energy loss and entropy change in the flow are clearly identified.

• Clean Technology
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• v.20 no.3
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• pp.290-297
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• 2014

Batch adsorption studies were carried out for equilibrium, kinetics and thermodynamic parameters for adsorption of coomassi brilliant blue G (CBBG) using activated carbon with varying the operating variables like initial concentration, contact time and temperature. Equilibrium adsorption data were fitted into Langmuir, Freundlich and Dubinin-Radushkevich isotherms. From estimated separation factor of Langmuir and Freundlich, this process could be employed as effective treatment for removal of CBBG. Also from Dubinin-Radushkevich isotherm model, adsorption energy (E) indicated adsorption process is physical adsorption. From kinetic experiments, the adsorption reaction was found to confirm to the pseudo second order model with good correlation. Intraparticle diffusion was rate controlling step. Thermodynamic parameters like change of free energy, enthalpy, and entropy were also calculated to predict the nature of adsorption. The change of enthalpy (406.12 kJ/mol) indicated endothermic nature of the adsorption process. The change of entropy (1.66 kJ/mol K) showed increasing disorder in process. The change of free energy found that the spontaneity of process increased with increasing adsorption temperature.

• Textile Coloration and Finishing
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• v.12 no.1
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• pp.52-60
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• 2000

In the prior studies, we reported that the dye uptakes of C. I. Disperse Violet 1 on polyester fiber in hexane and cyclohexane were higher than those in the other solvents, as the number of carbon atoms of alkanes decreased, the dye uptake increased, and the logarithmic plot of the dye uptakes vs. the solubilities of the dye showed that the dye uptakes are inversely proportional to the solubilities. In this study, for Interpretation of dyeing behavior of C. I. Disperse Violet 1 on polyester in alkanes, the thremodynamic parameters of dyeing, such as standard affnity, heat of dyeing(enthalpy change), entropy change, diffusion coefficient, and activation energy of diffusion, were obtained from isotherms and dyeing rates at different temperature. As the number of carbon atoms of alkanes increased, the standard affinity decreased, but the heat of dyeing(enthalpy change) and the entropy change showed larger negative values. These results mean that as the number of carbon atoms of alkanes increases, the dye uptake decreases, but both the fraction of the dye molecules dyed at relatively highly aligned or compact region of polyester fiber and the regularity of dye aggregates in the fiber become increased. As the number of carbon atoms of alkanes increased, the diffusion coefficient decreased, but the activation energy of diffusion increased. In the alkane of larger number of carbon atoms, because the solubility of the dye is higher, the desorption rate of the dye is faster and the diffusion coefficient is smaller than those in the smaller alkanes. But the energy required to separate the dye molecules from the alkane molecules is much higher because the interaction between the alkane molecule and the dye molecule become strong with the number of carbon atoms.