• Carbon letters
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• v.28
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• pp.105-110
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• 2018

Owing to their scalability, flexible operation, and long cycle life, vanadium redox flow batteries (VRFBs) have gained immense attention over the past few years. However, the VRFBs suffer from significant polarization, which decreases their cell efficiency. The activation polarization occurring during vanadium redox reactions greatly affects the overall performance of VRFBs. Therefore, it is imperative to develop electrodes with numerous catalytic sites and a long cycle life. In this study, we synthesized heteroatom-rich carbon-based freestanding papers (H-CFPs) by a facile dispersion and filtration process. The H-CFPs exhibited high specific surface area (${\sim}820m^2g^{-1}$) along with a number of redox-active heteroatoms (such as oxygen and nitrogen) and showed high catalytic activity for vanadium redox reactions. The H-CFP electrodes showed excellent electrochemical performance. They showed low anodic and cathodic peak potential separation (${\Delta}E_p$) values of ~120 mV (positive electrolyte) and ~124 mV (negative electrolyte) in cyclic voltammetry conducted at a scan rate of $5mV\;s^{-1}$. Hence, the H-CFP-based VRFBs showed significantly reduced polarization.

• Journal of Hydrogen and New Energy
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• v.29 no.1
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• pp.90-96
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• 2018

Reaction characteristics and kinetics of a oxygen carrier (OCN717-R1SU) for chemical looping combustion (CLC) have been investigated using TGA by changing gas concentration (10-30 vol.% $CH_4$) and reaction temperature ($825-900^{\circ}C$). Reaction rate of OCN717-R1SU increased as temperature increased and it was found that reaction is delayed at the initial reaction regime. Johnson-Mehl-Avrami (JMA) model was adopted to explain the reaction phenomenon. The activation energy (E) determined by JMA model in reduction reaction of OCN717-R1SU is $151.7{\pm}2.03kJ/mol$ and pre-exponential factor and JMA exponent were also obtained. The parameters calculated in this study will be applied in design of the reactor and operation conditions for CLC process.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.143-149
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• 2009

The marine leisure activities are specially increasing among the other leisure activities due to the improving of people's life quality and formation of people's values which pursuit the various life styles with the development of economy and society and operation the system of five working days per week. Among the various marine leisure activities, skin scuba diving is the mast prevalent activity, even though it doesn't have proper legal system in relation to the safety of the activity. Thus, this paper studies the various legal issues in relation to skin scuba diving to improve the safety and activation of the activity, and identifies the problems and proposes the ways of improving it.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.434-442
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• 2015

The advanced passive pressurized water reactor (PWR) is being constructed in China and the passive residual heat removal (PRHR) system was designed to remove the decay heat. During accident scenarios with increase of heat removal from the primary coolant system, the actuation of the PRHR will enhance the cooldown of the primary coolant system. There is a risk of power excursion during the cooldown of the primary coolant system. Therefore, it is necessary to analyze the thermal hydraulic behavior of the reactor coolant system (RCS) at this condition. The advanced passive PWR model, including major components in the RCS, is built by SCDAP/RELAP5 code. The thermal hydraulic behavior of the core is studied for two typical accident sequences with PRHR actuation to investigate the core cooling capability with conservative assumptions, a main steam line break (MSLB) event and inadvertent opening of a steam generator (SG) safety valve event. The results show that the core is ultimately shut down by the boric acid solution delivered by Core Makeup Tank (CMT) injections. The effects of CMT boric acid concentration and the activation delay time on accident consequences are analyzed for MSLB, which shows that there is no consequential damage to the fuel or reactor coolant system in the selected conditions.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.2
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• pp.181-192
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• 2002

The purpose of this study is to clarify the expression of conceptual image by which the modern graphic artists use for creating new visual images and the characteristics in expression of the major fashion images in fashion illustration. In the present study, major findings on the basis of the analysis of expression of visual images in fashion illustration since 1980s are as follow: The conceptual image expression in the visual arts is based on the eight techniques. They are dual image, operation of image, copying·reproduction of image, deconstruction of image, pictorial image, symbolization of image, mystification of image, and making humorous image. Since 1980s, the major fashion images in fashion illustration are mainly classified as classic image, humor image, fantastic image, natural image, avant-garde image, simple image, casual image and feminine image. The characteristics in expression of these images in fashion illustration are; 1) fortification of dual image in classic image, 2) activation in humor image 3) grotesque fantastic image, 4) the modernization of natural image, etc. In addition that, the image of avant-garde is expressed by Postermodernism, Deconstructionism, Techno etc. since 1980s. Also, simple image of the modern composition, casual image of daily life, and feminine image which is emphasized with eroticism are also included in these characteristic in expression of images since 1980s.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.3
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• pp.40-49
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• 2002

The objective of this research is to suggest the appropriate natural environment conservation facility management plan in Korea through development of the proper definition and categorization. Bearing the above objective, this study employs the comparison and analysis between domestic and international case studies. Furthermore, several survey methods have been adopted as check-lists for the evaluation of the sample sites and quantitative interviews with government officials and visitors to investigate their perspectives. On the consequence, firstly it was found that considering ecological types and objectives, the proper applicability of natural environment conservation facility could be disaggregated into three types of eco-park, eco-experience and education, and eco-observation facility. Secondly, based on the interview results, the necessity of provision of the natural environment conservation facilities was strongly found among the governmental officials and the residents groups who also expect the expansion of the facilities. Lastly, it appears necessary that the expansion of supporting projects and programs on the natural environment conservation facilities, the estimation and provision of the appropriate funding for monitoring, management and operation, the arrangement of resident experts, and activation of the nature environment education programs.

• Culinary science and hospitality research
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• v.23 no.3
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• pp.227-241
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• 2017

This study was conducted to examine the importance and satisfaction of quality attribute, popularization and tourism commercialization of Pohang local food. The purpose of this study was to provide useful information for establishing efficient marketing direction that serves the popularization and the activation of the Pohang local food. On the prospects and improvement of Pohang local foods and its use, 86.1% of subjects stated that the status quo was being maintained or only a portion of the foods was being transmitted. On the dissemination of local foods as world foods, subjects stated 'cooking methods' and 'simplified cooking methods' were required. In the IPA result of Pohang local food quality attributes, it is important to continuously keep 'health', 'nutrition', 'hygiene', 'preference (taste)', 'freshness', and 'credibility toward the ingredients', while 'service' needs to do intensive care and operation. The importance and satisfaction of attributes regarding plans for popularizing local foods and commercializing tourism differed, with importance and satisfaction on average being high, although attributes on plans for popularizing local foods and commercializing tourism was lower than the expectation of customers. Such results mean that residents have high expectations for Pohang local foods, on the other hand, the quality of local foods fails to satisfy the expectations of residents. Therefore, it is important to improve the quality of local foods overall.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.975-982
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• 2006

To cope with the recent developments of info-communication technology and information infrastructure, and in particular, to respond to the environment of wire and wireless communication integration, and also to overcome the limit of the existing web-based Port-MIS, the Ministry of Maritime Affairs and Fisheries is developing a mobile Port-MIS public service system (hereinafter referred to as a mobile Port-MIS). Accordingly, this study analyzes the current situation of the mobile Port-MIS that is under operation of the lust stage, finding out the problems, and suggesting new measures to activate the mobile Port-MIS. We expect this study will be able to suggest a guideline to the government institutions or other related organizations that plan to introduce a mobile technology in the near future.

• The Journal of the Korea Contents Association
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• v.8 no.5
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• pp.176-183
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• 2008

The transition to digital television is a massive and complex undertaking, affecting virtually every segment of the television industry and all viewers who watch television. In this respect, consequences of digital conversion of broadcasting and its related industries are so tremendous that countermeasure establishment for activation of digital broadcasting and programming industry is required. This paper explores the current situation of digital broadcasting in terms of the channel operation and contents focusing on the cases of the U.S. and U.K. In doing so, this paper presents reasonable directions and policy suggestions that should be resolved to advance Korean digital broadcasting.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.257-261
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• 2015

We report on GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) that can cover the spectral range of $3.6-25{\mu}m$. One advantage of the GaAs QWIPs is the wavelength tenability as a function of their structural parameters. We have performed a systematic calculation on the detection wavelength of a typical $GaAs/Al_xGa_{1-x}As$ multi-quantum-well photodetector, with the aluminum mole fraction (x) of $Al_xGa_{1-x}As$ barrier in the range of 0.15-0.43 and the quantum-well width range from 30 to 60 $60{\AA}$. Design and fabrication of a QWIP based on $GaAs/Al_{0.23}Ga_{0.77}As$ structure with $37{\AA}$-thick well width has been carried out. The calculated operation wavelength of the QWIP is in a good agreement with the experimental data taken by photo response and activation energy calculation from thermal quenching of integrated photoluminescence.