• Journal of Environmental Science International
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• v.24 no.8
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• pp.981-992
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• 2015

This study is mainly focused on micellar effect of tetradecyltrimethyl ammonium bromide(TTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). Dephosphorylation of DPNPIN is accelerated by $BI^{\Theta}$ ion in $10^2$ M Carbonate buffer(pH 10.7) of $4{\times}10^{-4}$ M TTABr solution up to 80 times as compared with the reaction in Carbonate buffer by no benzimidazole(BI) solution of TTABr. The value of pseudo first order rate constant($k_{\psi}$) of the reaction in TTABr solution reached a maximum rate constant increasing micelle concentration. The reaction mediated by $R-BI^{\Theta}$ in micellar solutions are obviously slower than those by $BI^{\Theta}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of $R-BI^{\Theta}$ in Stern layer of micellar solution. The surfactant reagent, TTABr, strongly catalyzes the reaction of DPNPIN with R-BI and its anion($R-BI^{\Theta}$) in Carbonate buffer(pH 10.7). For example, $4{\times}10^{-4}$ M TTABr in $1{\times}10^{-4}$ M BI solution increase the rate constant($k_{\psi}=99.7{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 28, when compared with reaction($k_{\psi}=3.5{\times}10^{-4}1/sec$) in BI solution(without TTABr). And no TTABr solution, in BI solution increase the rate constant($k_{\psi}=3.5{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 39, when compared with reaction ($k_{\psi}=1.0{\times}10^{-5}1/sec$) in water solution(without BI).

• The Journal of the Acoustical Society of Korea
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• v.28 no.2
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• pp.155-163
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• 2009

In text-to-speech systems, the conversion of text into prosodic parameters is necessarily composed of three steps. These are the placement of prosodic boundaries. the determination of segmental durations, and the specification of fundamental frequency contours. Prosodic boundaries. as the most important and basic parameter. affect the estimation of durations and fundamental frequency. Break prediction is an important step in text-to-speech systems as break indices (BIs) have a great influence on how to correctly represent prosodic phrase boundaries, However. an accurate prediction is difficult since BIs are often chosen according to the meaning of a sentence or the reading style of the speaker. In Japanese, the prediction of an accentual phrase boundary (APB) and major phrase boundary (MPB) is particularly difficult. Thus, this paper presents a method to complement the prediction errors of an APB and MPB. First, we define a subtle BI in which it is difficult to decide between an APB and MPB clearly as a variable break (VB), and an explicit BI as a fixed break (FB). The VB is chosen using the classification and regression tree, and multiple prosodic targets in relation to the pith and duration are then generated. Finally. unit-selection is conducted using multiple prosodic targets. In the MOS test result. the original speech scored a 4,99. while proposed method scored a 4.25 and conventional method scored a 4.01. The experimental results show that the proposed method improves the naturalness of synthesized speech.

• Korea Trade Review
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• v.47 no.4
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• pp.161-176
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• 2022

Most companies are achieving economic benefits by producing products in the form of bi-national products, but there are also negative consequences such as reduced brand power, so strategic bi-national product planning and branding is essential. In order to actively reflect these practical needs, this study conducted a comprehensive and easy-to-generalize evaluation of Bi-national products that has been somewhat underdeveloped in previous studies. To this end, the selection and evaluation criteria of the products to be investigated were differentiated. This is to classify the products by place of use and the purpose of use so that the majority of bi-national products can be included, and then use the combination to derive the specific products to be evaluated for bi-national products. The evaluation of the product identified the phenomenon of psychological conflict among consumers due to the country of origin discrepancy at the level of decreasing brand authenticity. The above research design is an evaluation method that can encompass bi-national products as a whole, rather than an evaluation of a specific product or product line that is mainly reported in previous studies, and it is also very easy to apply to practice because it allows us to more carefully identify changes in psychological attitudes.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.565-575
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• 2010

This study is mainly focused on micellar effect of cetylpyridinium chloride(CPyCl) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). The reactions of DPNPIN with R-BI$^{\ominus}$ are strongly catalyzed by the micelles of CPyCl. Dephosphorylation of DPNPIN is accelerated by BI$^{\ominus}$ ion in $10^{-2}M$ carbonate buffer(pH 10.7) of $4{\times}10^{-3}M$ CPyCl solution up to 100 times as compared with the reaction in carbonate buffer by no BI solution of $4{\times}10^{-3}M$ CPyCl. The value of pseudo first order rate constant($k^m_{BI}$) of the reaction in CPyCl solution reached a maximum rate constant increasing micelle concentration. Such rate maxima are typical of micellar catalyzed bimolecular reactions. The reaction mediated by R-BI$^{\ominus}$ in micellar solutions are obviously slower than those by BI$^{\ominus}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of R-BI$^{\ominus}$ in Stern layer of micellar solution. The surfactant reagent, cetylpyridinium chloride(CPyCl), strongly catalyzes the reaction of diphenyl-4-nitrophenylphosphinate(DPNPIN) with alkylbenzimidazole (R-BI) and its anion(R-BI$^{\ominus}$) in carbonate buffer(pH 10.7). For example, $4{\times}10^{-3}M$ CPyCl in $1{\times}10^{-4}M$ BI solution increase the rate constant ($k_{\Psi}=1.0{\times}10^{-2}sec^{-1}$) of the dephosphorylation by a factor ca.14, when compared with reaction ($k_{\Psi}=7.3{\times}10^{-4}sec^{-1}$) in $1{\times}10^{-4}M$ BI solution(without CPyCl). And no CPyCl solution, in $1{\times}10^{-4}M$ BI solution increase the rate constant ($k_{\Psi}=7.3{\times}10^{-4}sec^{-1}$) of the dephosphorylation by a factor ca.36, when compared with reaction ($k_{\Psi}=2.0{\times}10^{-5}sec^{-1}$) in water solution(without BI). This predicts that the reactivities of R-BI$^{\ominus}$ in the micellar pseudophase are much smaller than that of BI$^{\ominus}$. Due to the hydrophobicity and steric effect of alkyl group substituents, these groups would penetrate into the core of the micelle for stabilization by van der Waals interaction with long alkyl groups of CPyCl.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.12
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• pp.969-976
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• 2011

In this study we aims to evaluate the effects of 1/3 mol% $Co_3O_4$ addition on the reaction, microstructure development, resultant electrical properties, and especially the bulk trap and grain boundary properties of $ZnO-Bi_2O_3-Sb_2O_3$ (Sb/Bi=2.0, 1.0, and 0.5) system (ZBS). The samples were prepared by conventional ceramic process, and characterized by XRD, density, SEM, I-V, impedance and modulus spectroscopy (IS & MS) measurement. In addition of $Co_3O_4$ in $ZnO-Bi_2O_3-Sb_2O_3$ (ZBSCo), the phase development, density, and microstructure were controlled by Sb/Bi ratio. Pyrochlore on cooling was reproduced in all systems. The more homogeneous microstructure was obtained in ZBSCo (Sb/Bi=1.0) system. In ZBSCo, the varistor characteristics were improved drastically (non-linear coefficient ${\alpha}$=23~50) compared to ZBS. Doping of $Co_3O_4$ to ZBS seemed to form $V^{\cdot}_o$(0.33 eV) as dominant defect. From IS & MS, especially the grain boundary of Sb/Bi=0.5 system is composed of electrically single barrier (0.93 eV) and somewhat sensitive to ambient oxygen with temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.59-59
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• 2011

We will report atomically sharp epitaxial growth of $Bi_2Se_3$ three-dimensional topological insulator films on Si(111) substrate with molecular beam epitaxy (MBE). It was achieved by employing two step growth temperatures to prevent any formation of second phase, like as $SiSe_2$ clusters, between $Bi_2Se_3$ and Si substrate at the early stage of growth. The growth rate was determined completely by Bi flux and the Bi:Se flux ratio was kept ~1:15. The second-phase-free atomically sharp interface was verified by RHEED, TEM and XRD. Based on the RHEED analysis, the lattice constant of $Bi_2Se_3$ relaxed to its bulk value during the first quintuple layer implying the absence of strain from the substrate. Single-crystalline XRD peaks of $Bi_2Se_3$ were observed in films as thin as 4 QL. TEM shows full epitaxial structure of $Bi_2Se_3$ film down to the first quintuple layer without any second phases. This growth method was used to grow high quality epitaxial $Bi_2Se_3$ films from 3 QL to 3600 QL. The magneto-transport properties of these thin films show a robust 2D surface state which is thickness independent.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.1
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• pp.69-73
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• 2001

In this study, we fabricated Bi-2223/Ag high temperature superconducting tapes using PIT(Powder-In-Tube) process to apply the superconducting magnet, cable and etc. It is inevitable to deform the superconducting taps with axial strain for application. Therefore, for the characterization of the strain sensitivity of the superconducting properties, the degradation of Bi-2223/Ag tapes due to axial strain were investigated by measuring the critical current as a function of applied tension strain and external magnetic field. The critical current of Bi-2223/Ag tapes were decreased slightly up to 0.3∼0.4% applied strain but, drastically decreased more than these strains. Superconducting filament cores consisted of brittle ceramic fibers were broken easily by the large strain and current path were decreased simultaneously.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.810-813
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• 2000

In this study, we fabricated Bi-2223/Ag high temperature superconducting tapes using PIT (Powder-In-Tube) process to apply the superconducting magnet, cable and etc. It's inevitable to deform the superconducting tapes with axial strain for application. Therefore, for the characterization of the strain sensitivity of the superconducting properties, the degradation of Bi-2223/Ag tapes due to axial strain were investigated by measuring the critical current as a function of applied tension strain and external magnetic field. The critical current of Bi-2223/Ag tapes were decreased slightly up to 0.3∼0.4% applied strain but, drastically decreased more than these strains. Superconducting filament cores consisted of brittle ceramic fibers were broken easily by the large strain and current path were decreased simultaneously.

• Journal of the Korean Ceramic Society
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• v.32 no.2
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• pp.248-256
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• 1995

The electrical conducton in the sintered 3Bi2O3.WO3 solid electrolyte was investigated by measuring the conductivity and ionic transport number. The electrical conductivity was about three to ten times higher than that of YSZ at temperatures between 300 and 80$0^{\circ}C$. D.C. polarization method confirmed that 3Bi2O3.WO3 was predominantly an ionic conductor. Unlike the instability of high conductive fcc phase in the rare-earth oxide-Bi2O3 or Y2O3-Bi2O3 systems at temperature below $700^{\circ}C$, fcc phase in the 3Bi2O3.WO3 exhibited no transformation even after annealing over 900 hrs at 600 and $650^{\circ}C$. Two samples which had different grain sizes showed almost the same conductivity. This result suggests that the electrical properties of grain and grain boundry were very similar.

• Progress in Superconductivity
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• v.4 no.2
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• pp.162-167
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• 2003

The critical current value of Bi-2223/Ag tape can be influenced by various factors. In particular, it was known that properties of precursor powders could affect the formation of Bi -2223 and grain growth rate of the same. Since, moistures and organic matters can easily contaminate the precursor powders of Bi-2223 tapes and degrade properties of superconductors, the precursor powders should be kept in optimal conditions to minimize contamination. In this study, the effect of moisture and organic matters has been investigated. A Bi-2223/Ag tape contaminated with a large amount of moisture and organic matter has been characterized by low critical current values and bubbling. It has been found that as the quantity of moisture increases, the Bi-2223 phases are formed at lower temperature and the amount of non-superconducting phase increases.