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        검색결과 7

        1.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Silicon carbide (β-SiC) was synthesized through an improved sol–gel method, then Ni/SiC catalysts were prepared using a hydrothermal method. The catalysts were characterized using TEM, H2- TPR, CO2- TPD and N2- TPD, etc. The results showed that the synthesized β-SiC had a large specific surface area, promoting the dispersion of Ni species and thus exposing more active sites. The interaction between Ni species and β-SiC contributed significantly to catalytic performance. Furthermore, the strong alkalinity of catalyst could adjust the bond energy of the active metal and N (M–N), which were conducive to desorption of the recombinant N2 from the metal surface, promoting to ammonia decomposition. Among the Ni/SiC catalysts, 30Ni/SiC-700 synthesized with the Ni loading of 30 wt% and calcination temperature of 700 °C, exhibited the optimal ammonia conversion rate of 93.4% at 600 °C under the space speed of 30,000 mL∙gcat −1∙h−1, and demonstrated a long-term stability, suggesting a very promising catalyst in ammonia decomposition.
        4,200원
        2.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study delves into the potential application of whisker carbon nanotube (w-CNT) in terms of electrical heating performance, with a particular emphasis on its significance in high-efficiency electrothermal conversion applications. Meanwhile, a comparative study was conducted on traditional carbon nanotubes (T1 and T3) with different aspect ratios. A uniform and dense carbon nanotube paper (BP) was prepared using a vacuum filtration method, including single-layer (T1, T3 and w-CNT BP), double-layer gradient composite (T1/T3-g, w-CNT/T3-g), and mixed composite (T1/T3-m and w-CNT/T3-m). The thickness of each type of BP is approximately 100 μm. The results demonstrated that electrical conductivity and electrical heating performance of single-layer BPs follow the order of T1 > T3 > w-CNT. While, mixed composite BPs are superior to double-layer gradient composite BPs in electrical conductivity and thermal performance. Notably, w-CNT/T3-m BP exhibits excellent electrothermal performance. Under an applied voltage of 5 V, the surface temperature of w-CNT/T3-m BP reaches 190 ℃. When the voltage is increased to 6 V, the surface temperature rises by 150℃ within 10 s, reaching a steady-state temperature of 318 ℃. This excellent electrothermal performance can be attributed to the introduction of w-CNT, which has a perfect and defect free structure according to Raman analysis. In-depth analysis using X-ray diffraction (XRD) indicated a more complete and higher degree of crystallinity in the w-CNT structure. In summary, this study not only provides experimental and theoretical basis for the application of high-performance electrothermal materials based on carbon nanotubes, but also foreshadows their broad application prospects in the field of macroscopic materials.
        4,000원
        4.
        2023.07 구독 인증기관·개인회원 무료
        In recent years E-commerce platforms recommend some products for consumers based on their shopping history and user persona. However, sometimes, unfamiliar products or styles would be recommended to consumers unintentionally or intentionally. Curiosity drives consumers to try but this idea would be declined with the consideration of product fit uncertainty. Augmented Reality (AR) is the integration of digital information with the user‘s environment in real-time (Hilken et al. 2018), it can deal with issues related to physical apprehension that hinder consumers’ online shopping (i.e, clothes, cosmetics), especially for the unfamiliar style. This study aims to investigate whether AR technology could improve consumers' purchase likelihood. Augmented Reality (AR) can enhance customer experiences in a multichannel environment (Hilken et al. 2017). AR Integrates online experiences into the offline experience (Hilken et al. 2018), such as virtual try-on or magic mirrors. Customers often find it difficult to imagine how firms’ products and services fit them personally or fit with their environment (Hilken et al. 2018). Drawn on AR, consumers can easily evaluate the fitness between themselves and the selected products. Prior studies have explored the different underlying processes of why AR technology could improve consumer purchase intention and customer experience. For instance, according to the situated cognition theory, AR creates a feeling of spatial presence (Hilken et al. 2017). The usage of AR benefits mental imagery, improving decision comfort (Heller et al. 2019). AR can compensate for consumers’ need for touch and offer hedonic and/or utilitarian benefits (Gatter et al. 2022). Based on media richness theory, AR offers more information for customers (Hoffmann et al. 2022), which represents a fitting concept for customers to evaluate the product (Javornik 2016).
        5.
        2022.06 구독 인증기관 무료, 개인회원 유료
        With the continuous prosperity and development of the marine industry, the number of ships is increasing while greenhouse gas emissions are rising. In order to meet the relevant international ship emission regulations, the solution of developing electric ships is proposed. As the core device of the electric ship propulsion system, the maturity and applicability of power battery technology play a key role in the development of the electric ship. This article introduces the principles and advantages of the fuel cell, lithium-ion battery as well as supercapacitor battery, respectively, and analyzes the application status and challenges of power batteries in existing electric ships. The development direction and problems to be solved of power battery in current and future ship applications are put forward, which can provide a reference for further research.
        4,000원
        6.
        2020.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the molecular cloud G33.92+0.11A, massive stars are forming sequentially in dense cores, probably due to interaction with accreted gas. Cold dense gas, which is likely the pristine gas of the cloud, is traced by DCN line and dust continuum emission. Clear chemical differences were observed in different source locations and for different velocity components in the same line of sight. Several distinct gas components coexist in the cloud: the pristine cold gas, the accreted dense gas, and warm turbulent gas, in addition to the star-forming dense clumps. Filaments of accreted gas occur in the northern part of the A1 and A5 clumps, and the velocity gradient along these features suggests that the gas is falling toward the cloud and may have triggered the most recent star formation. The large concentration of turbulent gas in the A2 clump seems to have formed mainly through disturbances from the outside.
        4,000원
        7.
        2005.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Transient luminous events (TLEs; sprites, elves, jets and etc.) are lightning-related optical flashes occurring above thunderstorms. Since the first discovery of sprites in 1989, scientists have learned a great deal about the morphological, spectroscopic and electromagnetic characteristics of TLEs through ground and spacecraft campaigns. However, most of the TLE studies were based on events recorded over US High Plains. To elucidate the possible biasing effects, space-borne observations are needed and have their merits. Imager of sprites and Upper Atmospheric Lightning (ISUAL) on the FORMOSAT-2 satellite is the first instrument to carry out a true global measurement of TLEs from a low- earth orbit. In this short paper, we apply a common astronomical data analysis technique, two-color diagram, on the ISUAL spectrophotometer (SP) data. By choosing appropriated bandpasses and converting the measured flux of TLEs into the unit of magnitude, two-color diagrams of TLEs can be constructed. We demonstrate that two-color diagrams, which were constructed from the narrow-band spectrophotometer data, can be used to classify different types of TLEs and trace their temporal evolution. The amount of reddening due to Earth's atmosphere can also be estimated from two-color diagrams assembled from the broad-band spectrophotometer data.
        3,000원