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Kyosai, South Korea

Kwak D.-J.,Kyungsung University | Kim J.-H.,Kyungsung University | Park B.-W.,Kyungsung University | Sung Y.-M.,Kyungsung University | And 2 more authors.
Current Applied Physics | Year: 2010

Aluminium-doped zinc oxide (ZnO:Al) conducting layer was deposited on polyethylene terephthalate (PET) substrate by r.f. magnetron sputtering to investigate the possible application of the film as transparent conducting electrode for film-typed dye-sensitized solar cells (FT-DSCs). The structural and electrical properties of ZnO:Al thin film were influenced significantly by the position of PET substrate and by also gas pressure. The minimum resistivity of 2.1 × 10-3 Ω cm was obtained at gas pressure of 5 mTorr. The deposition rate of ZnO:Al film at 5 mTorr of gas pressure was 248 nm/min. The efficiency of prepared FT-DSCs sample with ZnO:Al electrode showed about 2.1% (FF: 0.54, Voc: 0.73 V, Jsc: 5.3 mA/cm2). © 2009 Elsevier B.V.

Jeong K.-S.,Kyungpook National University | Lee H.-C.,Kyungpook National University | Baek Y.-S.,Kyungpook National University | Park J.-H.,Koje College
Journal of Electrical Engineering and Technology | Year: 2013

This study proposes a voltage and reactive coordinative control strategy with distributed generator (DG) in a distribution power system. The aim is to determine the optimum dispatch schedules for an on-load tap changer (OLTC), distributed generator settings and all shunt capacitor switching on the load and DG generation profile in a day. The proposed method minimizes the real power losses and improves the voltage profile using squared deviations of bus voltages. The results indicate that the proposed method reduces the real losses and voltage fluctuations and improve receiving power factor. This paper proposes coordinated voltage and reactive power control methods that adjust optimal control values of capacitor banks, OLTC, and the AVR of DGs by using a voltage sensitivity factor (VSF) and dynamic programming (DP) with branch-and-bound (B&B) method. To avoid the computational burden, we try to limit the possible states to 24 stages by using a flexible searching space at each stage. Finally, we will show the effectiveness of the proposed method by using operational cost of real power losses and voltage deviation factor as evaluation index for a whole day in a power system with distributed generators.

Min C.,Dongseo University | Kim H.,Koje College
Journal of Tourism and Cultural Change | Year: 2013

Cross-cultural attitudes are gaining more importance as contacts between people from different cultures are increasing in a globalized world. This is particularly the case and relevant for the tourism industry. The major purpose of this study is to investigate the relationship between cross-cultural attitudes and the attitudes toward foreign language within the tourism education context. An empirical study of 482 tourism students in South Korea revealed that cross-cultural attitudes had significant associations with attitudes toward studying a foreign language. Specifically, the 'integrative attitude', among the three types of attitudes toward foreign language study, showed the highest relationship with the 'cross-cultural attitude', being followed by the 'intrinsically motivated attitude'. However, the 'instrumental attitude' showed no significant relationship. Based on these findings, a need to approach language study from cultural perspectives is emphasized, suggesting a provision of programs and activities inspiring direct and indirect contacts with foreign cultures and people. The integration of cultural aspects of the tourism industry into foreign language study was also discussed in this context. Finally, the study's results were compared with those of previous studies and a tentative generalization that foreign language study has an effect in reducing social distance was proposed. © 2013 Copyright Taylor and Francis Group, LLC.

Shin D.-C.,Koje College | Kim T.-G.,Pusan National University | Kim D.-W.,Daegu University
Experimental Mechanics | Year: 2015

The linear contribution of total energy release rate for fracture of ferroelectric materials was studied based on the linear theoretic framework of piezoelectricity using the double-torsion technique. It was found that three linear contributions of the total energy release rate for piezoelectric material are definitely associated with pure mechanical compliance, electromechanical compliance, and pure electrical capacitance. To confirm the entity of contributions, mechanical and electromechanical compliances were analyzed obtained from result of load vs. displacement measured on each electric field, and electrical capacitance was obtained from property and geometry of samples. © 2015 Society for Experimental Mechanics

Kim Y.-Y.,Korea University | Kwak T.-S.,Korea University | Kim K.-N.,Koje College
Journal of the Korean Ceramic Society | Year: 2010

This study has been focused on properties of mirror surface grinding technology by ELID(Electrolytic In-process Dressing) for structural ceramics using in high precision structural parts as like semi-conductor manufacturing processes. The experimental studies have been carried out to get mirror surface for grinding of structural ceramics, SiC, Al2O3 and AlN. Grinding process of the ceramics is carried out with varying mesh type, depth of cut and feed rate using diamond wheel. The machining result of the surface roughness and condition of ground surface, have been analyzed by use of surface roughness tester, SEM, AFM and three dimensional surface profiler measurement system.

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