• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.11-16
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• 2016

Silicon carbide (SiC) has received significant attention over the past decade because of its high-voltage, high-frequency and high-thermal reliability in devices compared to silicon. Especially, a SiC Schottky barrier diode (SBD) is most often used in low-voltage switching and low on-resistance power applications. However, electric field crowding at the contact edge of SBDs induces early breakdown and limits their performance. To overcome this problem, several edge termination techniques have been proposed. This paper proposes an improvement in the breakdown voltage using a double-field-plate structure in SiC SBDs, and we design, simulate, fabricate, and characterize the proposed structure. The measurement results of the proposed structure, demonstrate that the breakdown voltage can be improved by 38% while maintaining its forward characteristics without any change in the size of the anode contact junction region.

• Korean Journal of Materials Research
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• v.30 no.6
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• pp.285-291
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• 2020

Recent advances in technology using ultra-thin noble metal film in oxide/metal/oxide structures have attracted attention because this material is a promising alternative to meet the needs of transparent conduction electrodes (TCE). AZO/Ag/AZO multilayer films are prepared by magnetron sputtering for Cu₂ZnSn(S,Se)₄ (CZTSSe) of kesterite solar cells. It is shown that the electrical and optical properties of the AZO/Ag/AZO multilayer films can be improved by the very low resistivity and surface plasmon effects due to the deposition of different thicknesses of Ag layer between oxide layers fixed at AZO 30 nm. The AZO/Ag/AZO multilayer films of Ag 15 nm show high mobility of 26.4 ㎠/Vs and low resistivity and sheet resistance of 3.58^⁎10^-5 Ωcm and 5.0 Ω/sq. Also, the AZO/Ag (15 nm)/AZO multilayer film shows relatively high transmittance of more than 65 % in the visible region. Through this, we fabricated CZTSSe thin film solar cells with 7.51 % efficiency by improving the short-circuit current density and fill factor to 27.7 mV/㎠ and 62 %, respectively.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.209-220
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• 2017

Organizational environments are becoming increasingly complex, dynamic and interdependent. To overcome these environmental, the Organization pay attention to the Empowering Leadership. And Empowering leadership leads to OCB(Organizational Citizenship Behavior) of the organization's members. To the empirical analysis of the theoretical relationship, we was set up the research model based on the literature research method. We used total 346 questionnaires from the Manufacturing workers in Dea-gu and Kyung-buk region. The results of this study are as followings; First, Empoewering Leadership are positively related to OCBI and OCBO. Second, Self Leadership is positively related to OCBI and OCBO, and Trust is only positively related to OCBI. Third, the mediating effects of Self Leadership is a significant partial mediations effect on the relationship between Empowering Leadership and OCBI, OCBO. This result is contribute to the development of the research field leadership.

• Culinary science and hospitality research
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• v.23 no.6
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• pp.127-134
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• 2017

Despite its importance to Thailand, museum tourism has not received sufficient attention from researchers and practitioners. Consequently, knowledge of museum tourist responses toward museum service quality is quite limited. Thus, the purpose of this study was to (1) examine the service quality of museums in Thailand and (2) revealed how tourists react positively namely through satisfaction and revisit intentions. This study further explored how the proposed relationships vary between Asian and European tourists. Based on Harrison and Shaw's (2004) museum experience model, facilities, staff services, and exhibition experience were proposed as three important service elements encountered during a service experience. Data were collected from foreign tourists who visited any of the 6 national museums in Bangkok. A total of 260 questionnaires were obtained over a 3-month period, all of which were retained and utilized for the analysis. Results found that exhibition experience and staff services were positively associated with tourist museum visit satisfaction, which in turn acted on revisit intention. In addition, exhibition experience was found to be the most important service element for Asian tourists, while staff services was most important for European tourists. Staff services and exhibition experience both played important roles in the tourist museum experience, while facilities did not have an effect on the evaluation of museum services. In response, museum managers need to implement a segmentation strategy that considers tourists' backgrounds such as region, culture, or nationality.

• Earthquakes and Structures
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• v.8 no.2
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• pp.305-377
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• 2015

The problem of earthquake induced torsion in buildings is quite old and although it has received a lot of attention in the past several decades, it is still open. This is evident not only from the variability of the pertinent provisions in various modern codes but also from conflicting results debated in the literature. Most of the conducted research on this problem has been based on very simplified, highly idealized models of eccentric one-story systems, with single or double eccentricity and with load bearing elements of the shear beam type, sized only for earthquake action. Initially, elastic models were used but were gradually replaced by inelastic models, since building response under design level earthquakes is expected to be inelastic. Code provisions till today have been based mostly on results from one-story inelastic models or on results from elastic multistory idealizations. In the past decade, however, more accurate multi story inelastic building response has been studied using the well-known and far more accurate plastic hinge model for flexural members. On the basis of such research some interesting conclusions have been drawn, revising older views about the inelastic response of buildings based on one-story simplified model results. The present paper traces these developments and presents new findings that can explain long lasting controversies in this area and at the same time may raise questions about the adequacy of code provisions based on results from questionable models. To organize this review better it was necessary to group the various publications into a number of subtopics and within each subtopic to separate them into smaller groups according to the basic assumptions and/or limitations used. Capacity assessment of irregular buildings and new technologies to control torsional motion have also been included.

• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.123-156
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• 2005

Strengthening the competitive edge of SMEs has become one of the most important economic issues in Korea as the bipolarization between large firms and SMEs has deepened. Accordingly, small innovative firms (referred as 'venture firms' in Korea) attract keen attention both from policy makers and academia. Also, we can sufficiently observe how the growth environment for venture firms has evolved, since it has been almost ten years after the Korean government started its support policy for venture firms. Considering this, now is the appropriate time to carry out an analysis of venture firms. From this point of view, this study looks at growth factors for venture firms to draw out policy implications. The empirical analysis shows interesting results. Firms with the following features all showed higher growth rates: firms with high R&D intensity, younger firms, bigger firms, firms using more policy loans, and firms located within and around the Seoul region. However, the empirical analysis has some limitations. The data used in the study is limited in terms of firm information and so there are some insufficiencies. Thus it is of great importance to compile the required data on firms to enable further in-depth studies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.433-433
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• 2009

ZnO-based materials have been extensively studied for optoelectronic applications due to their superiors physical properties such as wide direct bandgap (~3.37 eV), large exciton binding energy (~60 meV), high transparency in the visible region, and low cost. Especially, one-dimensional (1D) ZnO nanostructures have attracted considerable attention owing to quantum confinement effect and high crystalline quality. Additionally, various nanostructures of ZnO such as nanorods, nanowires, nanoflower, and nanotubes have stimulated the interests because of their semiconducting. and piezoelectric properties. Among them, vertically aligned ZnO nanorods can bring the improved performance in various promising photoelectric fields including piezo-nanogenerators, UV lasers, dye sensitized solar cells, and photo-catalysis. In this work, we studied the effect of the annealing temperature of homo seed layers on the formation of ZnO nanorods grown by hydrothermal method. The effect of annealing temperature of seed layer on the length and orientation of the nanorods was investigated scanning electron microscopy investigation. Transmission electron microscopy and X-ray diffraction measurement were performed to understand the effect of annealing temperatures of seed layers on the formation of nanorods. Moreover, the optical properties of the seed layers and the nanorods were studied by room temperature photoluminescence.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.310-320
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• 2000

Statement of the problem. The record base in fabricating procedures of the complete denture, as a temporary form for reproducing denture base, is used to record upper and lower jaw relation and to align artificial teeth and try-in it in the mouth. The accuracy of jaw relation record is affected by the accuracy, stiffness and stability of the record base. So, the accuracy of record base is the most important requirements of jaw relation records. Purpose of study. The purpose of this study was to evaluate the gap that occurred over the palatal area of a maxillary record base fabricated with autopolymerizing resin and light-curing resin. Methods/material. The maxillary record bases were fabricated out of autopolymerizing resin that is used the most frequently in clinics and light-curing resin that attracts special attention for its several merits. The light-curing resin was made by two kinds of polymerization methods, which are one step curing method and multiple step curing method. All record bases were cut in certain positions of the master cast 1 hour and 1 day later after fabrication and the accuracy of the master cast was measured and analyzed with a microscope. Results. A pattern of gap formation between the record base and the maxillary cast was observed in all specimens. According to kinds of resins, autopolymerizing resin was significantly more accurate than light-curing resin. There was no statistical difference according to time lapse, and in all three groups, the maximum discrepancy occurred at the posterior border in the mid-palatal region. Conclusion. The autopolymerizing resin is better than light-curing resin, and multiple step curing method is more accurate than one step curing method when using light-curing resin.

• Journal of the Korean Geographical Society
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• v.40 no.1 s.106
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• pp.63-77
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• 2005

Innovation, esp. technological innovation, in service sectors has drawn much attention as innovation-driven economy and service-led growth has been emphasized in the 21st century. This paper attempts to analyze the technological innovation from the perspective of geography and to understand the role of cooperative networks in the technological innovation. In sum, this study reveals that more firms in the Seoul Metropolitan Area (SMA) tended to succeed in the technological innovation in service sectors than those in the provinces. However, the difference originated from the difference in firms' internal capabilities, not from the difference in the external innovative capabilities represented by cooperative networks relevant to innovative milieu. In terms of cooperative partners, the fm in the provinces placed special importance on universities as cooperative partners, while the firms in the SMA put much emphasis on various types of cooperative partners. The cooperation with private partners was a statistically meaningful variable for the occurrence of technological innovation, regardless of firms' location. The cooperation with public partners proved to influence firms' application for the intellectual property right such as patents in both the SMA and the provinces.

• Korean Journal of Biological Psychiatry
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• v.2 no.1
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• pp.107-114
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• 1995

This study was to investigate the anatomical evidence of anxiety. MRI was used to study 11 patients with panic disorder and 15 patients with complex partial seizure, and 21 controls. The regions of interest in the MRI were measured with computer-assisted planimetry using the AutoCad and digitizer. The following results were obtained ; 1) The mean age was 49.7(12.4) years in patients with panic disorder and 30.1(7.5) years in patients with complex partial seizure. 2) There were na signi ficant differences between 3 groups in the values of cerebral area, temporal lobe, caudate nucleus, hippocampus, parahippocampus, amygdala, third ventricle and VBR. The right parahippocampal region which attracted most attention in neurobiological studies regarding anxiety, tended to be larger in both study groups compared to the control group, but with no statistical significance. 3) There was lett-right reversal of temporal lobes in both study groups. And these are mainly due to asymmetrical increase in area of the temporal lobe on right side. These results suggest that temporal lobe, especially right temporal, is the anatomical correspondence of anxiety and functional activation of temporo-limbic system may be accompanied by the structural change of temporal lobe.