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        검색결과 10

        1.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Epoxy resin (EP) is a thermosetting resin with excellent properties, but its application is limited due to its high brittleness and poor flame retardancy. Therefore, to solve this problem, a dispersion system of imidazole-containing ionic liquid ([Dmim]Es) and graphene in epoxy resin is designed based on the π–π stacking effect between imidazole and graphite layers. The study on the thermal and flame-retardant properties of the composites show that the modified [Dmim]Es–graphene nanosheets improved the flame retardancy, smoke suppression and thermal stability of epoxy resin. With the addition of 5wt% [Dmim]Es and 1% Gra, the exothermic rate (HRR) and total exothermic (THR) of the composites decrease by 35% and 30.2% compared with the untreated epoxy cross-linking, respectively. The limiting oxygen index reaches 33.4%, the UL-94 test rating reaches V-0. The characterization of mechanical properties shows that the tensile properties and impact properties increased by 13% and 30%, respectively. Through SEM observation, the addition of [Dmim]Es improves the dispersion of graphene in the EP collective and changes the mechanical fracture behavior. The results show that ionic liquid [Dmim]Es-modified graphene nanosheets are well dispersed in the matrix, which not only improves the mechanical properties of epoxy resin (EP), but also has a synergistic effect on flame retardancy. This work provides novel flame-retardant and graphene dispersion methods that broaden the range of applications of epoxy resins.
        4,900원
        2.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The evolvement in the microstructure and electrical properties of PAN-based carbon fibers during high-temperature carbonization were investigated. The study showed that as the heat treatment temperature increases, the change of carbon fiber resistivity around 1100 °C can be divided into two stages. In the first stage, the carbon content of the fiber increased rapidly, and small molecules such as nitrogen were gradually released to form a turbostratic of carbon crystal structure. The resistivity dropped rapidly from 3.19 × 10− 5 Ω·m to 2.12 × 10− 5 Ω·m. In the second stage, the carbon microcrystalline structure gradually became regular, and the electron movement area gradually became larger. At this time, the resistivity further decreases, from 2.12 × 10− 5 Ω·m to 1.59 × 10− 5 Ω·m. During carbonization, the tensile strength of carbon fiber first increased and then decreased. This is because the irregular and disordered graphite structure is formed first. As the temperature rose, the graphite layer spacing decreased and the grain thickness gradually increases. The modulus also gradually increased.
        4,000원
        3.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the Anzunbaengi (Triticum aestivum) whole wheat flour mixture group, some herbs (A [white], B [yellow], C [black], D [blue], and E [red]) were added. The physicochemical properties were compared to the strong flour and whole wheat flour mixture groups. The dry gluten content of the control group (strong flour) was 13.5±0.4%, and the content in the whole wheat flour test group was slightly lower in value than the control group. The final viscosity, breakdown, and setback values of the dough were 248.4±0.8, 104.8±0.9, and 103.1±2.9 RVU, respectively. The breakdown was significantly different in the control and whole wheat flour groups. The setback value of the dough was increased by 30 RVU in the whole wheat flour test group compared to the control group by 103.1±2.9 RVU, but there was no significant difference between the test group samples. The consistency of the control dough was 500±10 FU, and the whole wheat flour test group was significantly increased to 585±10~599±10 FU, respectively. The absorption rate was about 2% higher in the whole flour test group than in the control group (66.2±0.3%). The pH of the control paste gradually decreased with fermentation time, and the results of whole wheat flour test group were similar (5.78±0.12~5.88±0.12). As the fermentation time increased, the volume of dough was increased and the result was slightly lower in the whole wheat flour test group than in the control group.
        4,000원
        4.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As goods and services powered by AI continue to proliferate, scholarly opinion seems to consider that current WTO law is insufficient to regulate trade in AI-powered products. The following reasons can help explain this perceived insufficiency of the WTO law: (a) AI-powered products are difficult to categorise within the perceived goods/services dichotomy under WTO law, thus causing uncertainties as to the applicable legal regime; and (b) the WTO law has yet to respond to the need for national governments to strike a balance between trade and controversial trade practices regarding AI-powered products. This paper argues that while current WTO law is far from perfect, it does partly regulate trade in AI-powered products. The following observations substantiate the partial regulation of trade in AI-powered products by the WTO law: (a) AI-powered products cannot escape existing WTO disciplines on trade in goods and trade in services, by virtue of either the involvement of AI or the perceived goods/services dichotomy; and (b) efforts to balance trade/non-trade interests associated with trade in AI-powered products are allowed under the GATT/GATS’ ‘public morals’ and security exceptions.
        4,600원
        5.
        2006.04 구독 인증기관·개인회원 무료
        Laser additive direct deposition of metals is a new rapid manufacturing technology, which combines with computer aided design, laser cladding and rapid prototyping. The advanced technology can build fully-dense metal components directly from CAD files with neither mould nor tool. Based on the theory of this technology, a promising rapid manufacturing system called "Laser Metal Deposition Shaping (LMDS)" is being developed significantly. The microstructure and mechanical properties of the LMDS-formed samples are tested and analyzed synthetically. As a result, significant processing flexibility with the LMDS system over conventional processing capabilities is recognized, with potentially lower production cost, higher quality components, and shorter lead time.
        6.
        2001.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have constructed the foundations to a series of theoretical diagnostic methods to probe the jet phenomenon in young stars as observed at various optical forbidden lines. We calculate and model in a self-consistent manner the physical and radiative processes which arise within an inner disk-wind driven magneto centrifugally from the circumstellar accretion disk of a young sun-like star. Comparing with real data taken at high angular resolution, our approach will provide the basis of systematic diagnostics for jets and their related young stellar objects, to attest the emission mechanisms of such phenomena. This work can help bring first-principle theoretical predictions to confront actual multi-wavelength observations, and will bridge the link between many very sophiscated numerical simulations and observational data. Analysis methods discussed here are immediately applicable to new high-resolution data obtained with HST and Adaptic Optics.
        3,000원
        7.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper reports a part of research work on earthquake resistance consideration in regions of moderate seismicity, which is being carried out in the Department of Civil Engineering, Hong Kong University of Science & Technology. The possible seismic hazard in Hong Kong, which is located in a region of moderate seismicity, is described. A case study is presented to compare the wind and earthquake effects on Hong Kong buildings and to assess whether seismic analysis and desing is necessary for building structure. Potential problems of reinforced concrete buildings under earthquake effects in regions of moderate seismicity are discussed.
        4,000원
        8.
        2018.05 KCI 등재 서비스 종료(열람 제한)
        Purpose - Based on preceding studies, this thesis focuses on the finding of the definition and category of mobile tourism application and deriving out its characteristics. And after looking for how they make influences on continuous intention to use, we make empirical study with TAM model. Research design, data, and methodology - There are many Chinese tourist who visit Korea with user's constant intention to use of tourism application. This study is to find out the definition and category of mobile tourism application through research of preceding study and to fomulate the research model and hypothesis that how tourism application attributes (convenience, interaction, accessibility, local basis, security) affect constant intention to use of mobile tourism application. In order to verify a hypothesis, we conducted a survey for Chinese users of tourism application. In empirical study, we analyzed a structure model for frequency analysis, reliability analysis, exploratory factor analysis, validity analysis through IBM SPSS Statistics 21.0 and IBM SPSS AMOS 21.0 Results - Among tourism applications, convenience, interaction, accessibility and local basis have positive effects on both perceived usefulness and perceived easiness respectively. But security does not. Also perceived easiness has a positive effect on perceived usefulness. Finally, perceived usefulness and perceived easiness have positive effect on constant intent to use. Conclusions - Tourism application enterprises should put emphasis on design such as menu or function in order to simplify the operation of new services for new customers. Therefore, comfortable user interface and development of useful function can improve tourism application. Consequently, it leads to the promotion of tourism application. Also, when users perceive tourism application as a useful media which is easy, comfortable and useful content, the degree of constant intention to use becomes increased. It is important to provide plentiful and useful contents for customers and to develop user interface such as easy operation because these factors have positive effects on constant demand and use of tourism application.
        9.
        2018.01 KCI 등재 서비스 종료(열람 제한)
        Purpose - This paper aims to identify factors that influence the users' word-of-mouth intention (WOMI) regarding mobile apps, focussing on the impacts of technology acceptance model (TAM) and social network theory. Research design, data and methodology - Based on TAM, this study integrates social network theory into the research model. The 317 sets of data collected in a survey were tested against the model using SmartPLS. Results - Our findings suggest the following: 1) Personal innovativeness positively influences perceived usefulness (PU), perceived ease of use (PEU) and perceived enjoyment (PE); 2) PEU affects PU and PE; 3) Both PU and Satisfaction are directly correlated with WOMI. Although PEU and PE has no direct impact on WOMI, they may indirectly affect WOMI via Satisfaction, as PU, PEU and PE all positively influence satisfaction; 4) Network density and network centrality both play a mediating role in the relation between PEU and WOMI. Referral Reward Program have a positive moderating effect on the relation between PU and WOMI. Conclusions - The findings of this study illustrate the traits of Apps that can promote users’ WOMI, as well as the characteristics of people who are more likely to participate in the word-of-mouth process. The findings provide a theoretical basis for app developers to make word-of-mouth a marketing strategy.
        10.
        2010.09 KCI 등재 서비스 종료(열람 제한)
        Modified compact combline bandpass filters are proposed based on the miniaturized quarter-wave transmission line which is composed of the parallel coupled line and lumped capacitors. The electrical length of the parallel coupled line in a resonator, which determines the size of combline bandpass filters, is just 5˚ or 7˚, resulting in a compact circuit area. The designed combline bandpass filter also has a wide upper stopband by suppressing the spurious passbands, not moving. Measured results of two fabricated filters centered at 400MHz show good agreement with the theoretical predications.