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        검색결과 1,884

        1.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Today, the principles of green chemistry are being fundamentally applied in the chemical industry, such as the nitrobenzene industry, which is an essential intermediate for various commercial products. Research on the application of response surface methodology (RSM) to optimize nitrobenzene synthesis was conducted using a sulfated silica (SO4/SiO2) catalyst and batch microwave reactor. The nitrobenzene synthesis process was carried out according to RSM using a central composite design (CCD) design for three independent variables, consisting of sulfuric acid concentration on the silica (%), stirring time (min), and reaction temperature (°C), and the response variable of nitrobenzene yield (%). The results showed that a three-factorial design using the response surface method could determine the optimum conditions for obtaining nitrobenzene products in a batch microwave reactor. The optimum condition for a nitrobenzene yield of 63.38 % can be obtained at a sulfuric acid concentration on the silica of 91.20 %, stirring time of 140.45 min, and reaction temperature of 58.14 °C. From the 20 experiments conducted, the SO4/SiO2 catalyst showed a selectivity of 100 %, which means that this solid acid catalyst can potentially work well in converting benzene to nitrobenzene.
        4,600원
        5.
        2024.07 구독 인증기관 무료, 개인회원 유료
        This study responds to literature calls to investigate the different social and psychological antecedents of negative consumer emotional well-being in the context of the health crisis Covid-19. We perform a path analysis on a sample of Australian consumers during the Covid-19 lockdown. We find that social norms and word-ofmouth increase consumer fear-of-missing-out which in turn fuels panic buying behavior. Such behavior is moreover spurred by positive motivations to panic buy. By contrast, we find that consumer ability to self-regulate during Covid-19’s reduces their tendencies to succumb to panic buying. We moreover find that such self-regulation is enhanced through sustainable product consumption behavior during Covid-19. Lastly, it was found that panic buying has a negative influence on emotional well-being of consumers. Implications of our findings for theory and future research directions are provided.
        4,000원
        6.
        2024.07 구독 인증기관 무료, 개인회원 유료
        This research aims to analyse consumers’ (Millennials and Gen Z) luxury consumption behaviour by focusing on the intrinsic and extrinsic motivations that drive consumption of luxury goods. Then, the study investigates whether they prefer to purchase offline or online for luxury goods. Lastly, it analyses which media most influences individuals when it comes to luxury consumption. An online survey is developed and distributed to Millennials and Gen Z. A first round of data collection took place in 2022 and a second round of data collection will take place at the beginning of 2024. Initial findings show that consumers are driven by intrinsic rather than extrinsic motivations when purchasing and who influences more when buying luxury online. Furthermore, it emerges that consumers prefer to shop offline, highlighting the importance of physical stores.
        4,000원
        20.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Carbon fusion is important to understand the late stages in the evolution of a massive star. Astronomically interesting energy ranges for the 12C+12C reactions have been, however, poorly constrained by experiments. Theoretical studies on stellar evolution have relied on reaction rates that are extrapolated from those measured in higher energies. In this work, we update the carbon fusion reaction rates by fitting the astrophysical S-factor data obtained from direct measurements based on the Fowler, Caughlan, & Zimmerman (1975) formula. We examine the evolution of a 20M⊙ star with the updated 12C+12C reaction rates performing simulations with the MESA (Modules for Experiments for Stellar Astrophysics) code. Between 0.5 and 1 GK, the updated reaction rates are 0.35 to 0.5 times less than the rates suggested by Caughlan & Fowler (1988). The updated rates result in the increase of core temperature by about 7% and of the neutrino cooling by about a factor of three. Moreover, the carbon-burning lifetime is reduced by a factor of 2.7. The updated carbon fusion reaction rates lead to some changes in the details of the stellar evolution model, their impact seems relatively minor compared to other uncertain physical factors like convection, overshooting, rotation, and mass-loss history. The astrophysical S-factor measurements in lower energies have large errors below the Coulomb barrier. More precise measurements in lower energies for the carbon burning would be useful to improve our study and to understand the evolution of a massive star.
        4,000원
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