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        검색결과 20

        1.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A combination of a series of epoxy coatings filled with octadecylamine (ODA)-modified graphene oxide (mGO) or commercial exfoliated graphite nanoplatelets (xGnP) was developed to boost the anticorrosion performances of mild steel substrates in acidic and NaCl aqueous solutions. The xGnP and mGO were applied successfully as fillers for the preparation of layer by layer (LBL) xGnP or mGO/epoxy coatings, respectively, which were coated on the clean steel surfaces to form LBLassembled layers. The LBL-assembled xGnP or mGO/epoxy coating-coated steel substrates exhibit excellent anticorrosion performances. The corrosion potentials (Ecorr) of xGnP-1/xGnP-2/3 and mGO-1/mGO-2/3 display at − 193 and − 150 mV, respectively, while Ecorr of the bare steel shows at − 871 mV of immersion in the 3.5 wt% NaCl solution. The most positive Ecorr values are obtained for xGnP-1/2/3 (− 117 mV) and mGO-1/2/3 (− 66 mV), showing the best anticorrosion performances compared to the bare steel (− 404 mV) in 17 wt% HCl solution.
        4,000원
        2.
        2023.07 구독 인증기관·개인회원 무료
        This study examines the impact of influencer-audience and audience-audience interactions in Livestream e-commerce by extending halo of the influencer to the brand and snowballing the opinions that empower other watchers. It finds that halo effect generates from influencer physical attraction and bandwagon effect from audience live comments significantly influenced product preference and purchase intentions.
        3.
        2023.07 구독 인증기관·개인회원 무료
        In the new digital age, the emergence of user-generated content enables consumers to enjoy greater freedom and control over their behavior on the internet and assume more active roles in sharing brand-related information with others. This research examines the role of brand engagement on consumer psychological ownership, purchase intention, electronic word of mouth (eWOM), and consumers’ willingness to defend the brand on social media. The findings provide evidence of consumer psychological process to demonstrate that companies can use social media to engage with consumers, so consumers are likely to spread positive WOM and be protective of the brand. It is important for marketing managers to assess the level of brand engagement on social media sites and develop tools and techniques to increase consumers’ participation such as using subliminal priming on brand image, with an aim to create a close consumer brand relationship.
        4.
        2023.07 구독 인증기관·개인회원 무료
        Webpage cookies collect and authorize access to users’ online footprints and regulate the data authorization for access, sharing, and usage. Data authorization, which is built based on, but exceeding cookies protocol, enables personalized recommendations under the framework of data-driven content-user matching in a way against customer privacy invasiveness and data breaches. However, gaps exist in how users’ desire for a personalized experience and the site’s perceived ethics contribute to the site-trust and cookies acceptance of categories at each type of site and how businesses’ reward incentives and cookie-based controls may intensify the willingness to contribute to the user data donation continuously.
        5.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon/carbon composites are widely used in re-entry engineering applications thanks to their excellent mechanical properties at high temperatures, but they are easily oxidized in the oxygenated atmosphere. It is important to research their residual mechanical properties influenced by oxidation behaviour, in order to ensure the in-service safety. A microscale degradation model is proposed to predict the oxidation behavior based on the mass conservation and diffusion equations, the derived equivalent steady recession rate of composite is employed to evaluate the residual mechanical properties of the oxidized composite theoretically. A numerical strategy is proposed to investigate the oxidation mechanism of this composite. The differences in the degradation rate between the fiber and the matrix resulted in the steady state and an unchanged shape of the front. Residual mechanical properties of composite with three different domains of oxidation were simulated with a multiscale coupled model. The numerical results demonstrated that the mechanical properties of this composite decreased by 24–32% after oxidation for 30 min at 850 °C. Oxidation also caused the stress redistribution inside components, with the stress concentration diminishing their load-bearing capacity. The local areas of increased stress in the pyrocarbon matrix provided new ways for diffusion of oxygen into the pyrocarbon matrix and fibers.
        4,300원
        6.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hydrogen energy is a promising source of renewable and clean energy for various industries, such as chemical, automobile, and energy industries. Electrolysis of water is one of the basic methods for the production of hydrogen energy. However, the high overpotential of the oxygen evolution reaction (OER) in water electrolysis has hindered the effective production of hydrogen using this method. Thus, the development of high-efficiency non-precious metal-based electrocatalysts for OER is extremely significant. In this study, we adopted a one-step hydrothermal method to fabricate Ni-based catalysts with N/Sdual doped graphene oxide/carbon nanotube (GO/CNT) supports using thiourea ( CH4N2S) and urea as the S source and the N source. It was observed that the amount of thiourea utilized in the synthesis of the catalyst affected the morphology, composition, and the electrochemical properties of the catalyst. For a GO/CNT-to-thiourea mass ratio of 1:10, the catalyst exhibited the highest activity, where the OER overpotential was 320 mV at a current density of 10 mA/cm2. This was attributed to the high specific surface area, high conductivity, and fast electron transport channels of the N/S-dual doped GO/ CNT composite. Furthermore, sulfurization of the Ni particles to form nickel sulfide played a significant role in enhancing the catalytic performance.
        4,000원
        9.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Highly luminescent carbon quantum dots (CQDs) are developed as fluorescent probes for selective detection of the heavy-ion Fe3+, where the CQDs exhibit excellent nontoxicity, functionalizability, sensitivity, and selectivity. Biomass-based CQDs and nitrogen-doped CQDs (N-CQDs) are synthesized for the selective detection of Fe3+ by using H2O2 as an oxidant and polyetherimide (PEI) as a nitrogen precursor by a green hydrothermal synthesis method. The prepared CQDs and N-CQDs exhibit an elliptical morphology and with an average particle size of 7 and 4 nm, respectively, and emit blue photoluminescence at 445 and 468 nm under excitation at 367 and 343 nm, respectively. The CQDs and N-CQDs exhibit good water solubility because of the abundant hydroxyl and carboxyl/carbonyl groups and graphic/pyrrolic/pyridinic nitrogen on the surfaces, giving rise to a quantum yield of about 24.2% and 30.7%, respectively. Notably, the Matrimony vine-PEI-based CQDs exhibit excellent Fe3+ selectivity and sensitivity relative to the Matrimony vine-based CQDs due to complexation of the numerous phenolic hydroxyl groups and nitrogen-containing groups with Fe3+, leading to increased fluorescence quenching, which greatly improves the sensitivity of detection. The minimum detection limit was 2.22 μmol L− 1 with a complexation constant of 44.7.
        4,000원
        10.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nitrogen-doped carbon dots (N-CDs), derived from the biomass (anthocyanin), are the novel additive to the nanocarbon materials, which is expected to bring a wide spectrum of novel applications. Moreover, metallic oxides are emerging for their unique potential for electrocatalysis. Herein, we report the synthesis of N-CDs for the selective detection of Fe3+ with a limit of detection of 2.57 μM in the range of 5–60 μM using ethylenediamine and H2O2 by a hydrothermal method. The obtained N-CDs displayed a spherical morphology with a particle size range of 2–7 nm and emitted blue luminescence at 394 nm under excitation at 319 nm. Meanwhile, we have demonstrated the fabrication of cost-efficient electrocatalysts for oxygen evolution reaction (OER) in an alkaline medium, employing N-CDs. Owing to the successful incorporation of N-CDs into NiO nanospheres, the resulting N-CDs/NiO with large surface areas, fast charge transfer, and increased conductivity vastly improved the catalytic activity. Remarkably, the optimal of N-CDs/NiO composite requires the overpotential of only 380 mV at a current density of 10 mA cm− 2 and a relatively low Tafel slope of 57.96 mV dec− 1 compared with pure NiO. These results open up a facile route for the application of N-CDs and offer prospects for CD-metal hybrids as high OER catalysts in electrochemical energy devices.
        4,300원
        11.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hierarchical porous carbons (HPCs) have been successfully prepared by a facile carbonization and subsequent CO2 activation process using corncob as a natural carbon precursor and Mg(C2H3O2)2 as a MgO nano-template precursor. The prepared corncob-based hierarchical porous carbons (C-HPCs) with desirable micropores and mesopores feature the excellent absorbency of gas (i.e., CO2 and CH4) and solution (i.e., methylene blue (MB)). Increasing the ratio of Mg(C2H3O2)2/corncob enlarged the specific surface area up to 1004 m2/ g, micropore and mesopore volumes, CO2, CH4, and MB adsorption capacities (112, 31 and 230 mg/g after 325 min, respectively). The results indicated that the pore structures of C-HPCs can be easily and suitably controlled by the amount of the template precursor and CO2 activation effecting concurrently, which leads to fascinating adsorption capacity for CO2, CH4, and MB.
        4,200원
        13.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the amendment of Child Welfare Law in 2003, the regional centers for children have been a part of the child welfare system, providing child-care services for families in poverty. In Korea, the regional centers for children were established during the poverty movement in the 1970s and have been developed as childcare providers for poor children since the financial crisis. However, the identity of regional centers for children is being threatened as the universal perspective on caring and the public values of caring services are being strengthened. There has raised a controversy around the role of regional centers for children that provide child-care services for vulnerable families. In addition, the survival of the regional centers for children is being threatened due to some issues regarding the content of their program as it is similar to those of other child-care agencies, the lack of cooperation among the ministries of government addressing public needs for child-care services, the poor working conditions of center employees, and the poor quality of services. The purpose of this study is to examine the formation process of the regional centers for children. After that, we discuss the current issues of the regional centers for children and seek alternatives that can settle the problems and respond properly to social changes.
        4,300원
        14.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature (600–850°C) on the CO2 adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of 1488 m2 g–1 was achieved at an activation temperature of 800°C (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to 850°C. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, CO2 adsorption isotherms showed that AC-800 exhibited the best CO2 adsorption capacity of 110 mg g–1 at 298 K and 1 bar.
        4,000원
        15.
        2018.07 구독 인증기관·개인회원 무료
        Based on survey data from 160 importing firms from 33 countries/regions, this study examines the effects of firm-owned versus sales rep-owned commitment on firm performance across varying degrees of economic distance between import and export countries. Results reveal both firm- and rep-owned commitment have positive effects on the export firm’s financial outcomes including the current and predicted future purchase share. Moreover, findings show that the larger the economic distance, the stronger the effect of rep-owned commitment but the weaker the effect of firm-owned commitment on sales performance. We also find two important antecedents to rep-owned commitment: economic-based instruments and relationship-based instruments, whereas only economic-based instruments have positive effect on firm-owned commitment.
        16.
        2018.07 구독 인증기관 무료, 개인회원 유료
        Theoretical Background Online tribalism is an unofficial network in virtual community due to common interests and affiliation to a topic, a belief, a figure, a ritual, or a culture (A. Taute and Sierra 2014, Badrinarayanan, Sierra and Taute 2014, Hamilton and Hewer 2010). In an interconnected world, consumers influence each other by initiating, spreading, appraising, receiving and internalising beliefs via social network and shape self - attitude and information status (Hilder 2004). These widely-existing phenomena suggest more efforts to be completed to address the gaps in knowledge in the following aspects: First, the information dissemination process should be understood with a stronger support of quantifying approaches to bring forward a systematic understanding to accommodate a wide range of drives for the complex social learning and assimilating procedure (Feliciani, Flache and Tolsma 2017, Macy et al. 2003, Huet, Deffuant and Jager 2008). For example, many qualitative research such as digital anthropology and netnography abound to explain the motivations, process, and outcomes of disseminating messages in the texture of social group (Flache and Macy 2011, Granovetter 1977). As the consequence, many tentative explanations have attempted to focus on the utilities of information circulation (Dupor, Kitamura and Tsuruga 2010, Gruhl et al. 2004, Kim and Baek 2014) and social influences (Gupta and Kim 2004, Kim and Baek 2014) but ended up with only incapability of modelling and quantifying the process. Within this trend, notably, two factors underpinning the changes in virtual community, i.e., individual’s information utility, motivation of seeking for conformity, remains a secret. In addition, it’s unclear that why and how active customers behave different from inactive ones from a perspective of information flow and social learning. Second, there is a lack of knowledge of how the intrinsic connections and dialectical dynamic between self-solicited individuals take place and adapt in the growth and evolution. With the tool of digitals, paradoxically, the essential ambiguity of digital openness and closure (Phelps et al. 2004), viability and tribalism (A. Taute and Sierra 2014, Badrinarayanan et al. 2014, Hamilton, Schlosser and Chen 2017), enculturation and acculturation, devastatingly remains under-investigated. Among these various perspectives to explain and model the dynamics of online community and social learning, there should exist a general framework that combines decisive bases of recipients and senders with various motives and constraints, with both subjectivity and objectivity. Opinion dissemination can therefore be understood not only as an objective procedure, but also with subjective intervention of participants where cognitive, psychological, and sociocultural factors intertwine to influence the collective learning pattern. Thirdly, some contextual findings are to be tested how the conditional relations may be established under different social settings. For example, theories show that engaged consumers usually exhibit enhanced consumer loyalty, satisfaction, empowerment, connection, emotional bonding, trust and commitment. However, literature rarely provide an answer that within a social group, how are traditions, patterns, communications, rewards, and punishments formed and evolved to lead to either conformity or dispute. To address the above gaps, this research adopts an interactive approach to deconstruct information into inputs (motivation, potential), action (interpersonal connection), and output (utility and identity). This research delivers several simulated experiments to identify how the evolution of customer opinions evolves out various patterns of self-efficacy and social recognition. The author assembles four aspects of input variables, including information utility, accordance utility, self-efficacy, and social status of consumers, and test the overall information prosperity and propensity of the social earning with different activeness levels. Findings The analytical firstly results show that active individuals exist in social group as the information hubs to dismiss the information and share a higher level of delight of owning knowledge and over time, become similar in knowledge standard. Consequently, a wider connection with and influence on mass audience of active members usually lead to a higher psychographic gain of attitudinal accordance compared with inactive and isolated ones in group. Secondly, at the individual level, the author found that the activeness in tribal group obviously result in a higher level of both self-recognition and social recognition on average. This pattern is consistent with vast literature in ethnography. And the relation between the activeness level and the self- and social-recognition level is positive. While at the aggregate level, it’s investigated that active individuals of online tribes have a stronger inclination, evidenced by a stronger propensity of spreading message, to further generate messages to impact other more profoundly when compared with inactive ones. The simulation experiment also indicated that a few contextual relations between variables, e.g., information-based and accordance -based delights, self-recognition and social recognition, information prosperity and transmission propensity, etc., moderated by the member activeness. It’s also found that extreme active individuals have a much higher marginal increase in accordance originated from the growing information volume owned in the process of influencing the society. Not coincidentally, their overall social recognition and attitudinal accordance from the group are significantly higher by the growth of personal knowledge. Conclusions This research contributes to the literature on the drives of tribal dynamics and its’ consequences on the changes of information valence and attitudinal changes and further to this, how the engagement level of individuals will influence these micro and macro outcomes. Notably, by adopting a self-reasoning method, the motives and outcomes are incorporated in a simulated method to develop not only the individual and the aggregate level of outcomes. This study also bears methodological significance by examining a series of hypotheses under the setting of a simulated online community. These findings suggest a series of contextual causality moderated between the characteristics, intentions and actions.
        3,000원
        17.
        2018.07 구독 인증기관·개인회원 무료
        Human beings are intrinsically social. How social interaction among tourists affect their experience remains under-represented. Drawing on S-O-R theory, social integration theory and social penetration theory, this study proposes and empirically tests a conceptual model that integrates self-disclosure, perceived cohesion, perceived intimacy, tourist engagement and tourist satisfaction with the experience. Also, the tie strength is theorized as a moderator in the relationship between self-disclosure and perceived cohesion as well as perceived intimacy. A field experiment was undertaken to collect data. The results from the structural analysis suggest that self-disclosure influences perceived cohesion and perceived intimacy, which in turn influence their engagement and satisfaction with tourism experience. Moreover, the initial tie strength has moderation effect on the relationship between self-disclosure and perceived cohesion as well as perceived intimacy. Overall, findings of this study contributes to the development of tourism experience research from the perspective of tourist-to-tourist interaction, and broadens the research on tourist engagement. Discussions and implications for tourism operators, limitations, and suggestions for future research are also provided.
        19.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Research and a, pp.ication of earthquake protection system in Taiwan have become very active since about ten years ago. Many passive isolators, etc., have been studied extensively. These studies have resulted in a few practical a, pp.ications and proposals of two draft design provisions for seismic isolation design of bridges and buildings. In addition to the pass control, analytical studies on active semi-active control have also been very active and the experimental studies have scheduled in the near future. This paper summarise the progress on recent research and a, pp.ication of earthquake protection systems in Taiwan. The emphases are given to the control systems that have been a, pp.ied in practical a, pp.ications.
        4,500원