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        검색결과 2,950

        207.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Laser-induced graphene (LIG) uses a CO2 infrared laser scriber for transforming specific polymer substrates into porous graphene. This technique is simple, scalable, low-cost, free of chemicals, and produces a 3D graphene for applications across many fields. However, the resulting 3D graphene is highly sensitive to the lasing parameters used in their production. Here, we report the effects of power, raster speed, number of lasing passes (with and without spot overlapping) on the resulting LIG structure, morphology, and sheet resistance, using a polyimide (PI) substrate. We find that the number of lasing passes, laser spot overlapping and brand of PI used had a strong influence on the quality of the LIG, measured in terms of the IG/ ID and I2D Raman bands and sheet resistance. Increasing number of passes and overlapping of laser spots led to increased LIG pore sizes, larger graphene scales, and reduced sheet resistance. Furthermore, the over-the-counter desktop CO2 laser engraving unit used introduced additional restrictions that limited the quality of the LIG produced, particularly due to inconsistent control of the laser scribing speed and a poor thermal management of the laser unit.
        4,000원
        208.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Core–shell ZIFs wrapped CuO hybrid materials (CuO@ZIF-67(Co)) were designed, synthesized, characterized, and employed as peroxymonosulfate (PMS) activators to degrade methylene blue (MB). It demonstrated outstanding catalytic activity on account of the unique structure and the synergistic effect between CuO cores and ZIF-67(Co) shells, resulting in complete degradation of MB (10 mg/L) in 1 min. Reactive oxygen species (ROSs) research showed that both SO4 − and OH were responsible for the removal of MB. The synergistic activation mechanisms in the CuO@ZIF-67(Co)/PMS system were investigated, which mainly involved the effective electron transfer of CuO and ZIF-67(Co) for accelerating the cycle of CuII/ CuI and CoIII/ CoII. This study broadens the application of MOF-derived materials for wastewater treatment.
        4,500원
        209.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To determine the acceptability of Grain Utilization Value Added (GUVA) Japonica rice variety developed by the International Rice Research Institute (IRRI) and South Korea’s Rural Development Authority (RDA), home use tests were conducted in n=69 businesses that were using Japonica rice. In general, they were satisfied with the Japonica brands, because they provided them with the particulars needed in their Japanese and Korean dishes. According to them, the value and quality of the Japonica rice justify the price. However, the GUVA Japonica Rice variety’s positive ratings were significantly lower compared to the brands they were used to. This applied to both their overall and attributespecific evaluations. Among the attributes, size, shape, aroma, and stickiness received significantly lower ratings compared to the other Japonica varieties. For them, it was too small, too round, less aromatic, and less sticky which may lead to challenges in preparation consequently affecting the commercial acceptability of the dishes they offer. Even with this experience and perception, they were still willing to consider the GUVA Japonica Rice when it was available in the market. Using the Van Westendorp pricing model, GUVA Japonica yielded a price of PHP 51.00 (1.01 USD) which was competitive. These findings provide recommendations for measures that should be put in place so that value chain players can preserve and maintain quality until the rice reach the business market.
        4,500원
        210.
        2023.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper was to provide a theoretical outline of why critical media literacy (CML) should be included in Korean English education teaching practices and teacher training curricula. CML is a pedagogy designed to sensitize students to ideological meanings embedded in media that socialize people into specific values, beliefs, and behaviors. This paper begins with a review of theoretical foundations of CML including the symbolic nature of human consciousness signification and the processes of socialization, which are theoretically encapsulated within the dialectic among post-structural theories of discourse and representation. A review of literature on CML and its application to English as a foreign language (EFL) is then presented. Applications of CML include situated inquiry, discussion, creation of group multimodal projects suggests, how it fosters the development of critical thinking skills, the acquisition and use of new vocabulary idioms, and transforming student perceptions of themselves and their society.
        6,600원
        211.
        2023.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Using vocabulary learning strategies allows learners to gain vocabulary autonomously. This study presents data from a self-report survey of Korean university students comparing meaning discovery strategies they employ to comprehend unknown singleword items and unknown idioms. Survey data recorded strategies used by learners, and effectiveness of these strategies measured by rates of correct meaning discovery. The survey revealed that learners relied on context clues, dictionaries, and vocabulary analysis for both idioms and single word vocabulary items with equal effectiveness. Dictionary use was the most effective strategy for correct meaning discovery for both types of vocabulary, although context clues might be a positive factor for idioms but not for single-word items. Data also showed that learners tended to apply strategies methodically rather than heuristically but that methodical application did not necessarily translate into higher rates of correct meaning discovery. Implications for learners and paths for further research are discussed.
        5,400원
        214.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The surface of carbon films deposited with inverted plasma fireballs is analysed in this paper. Measurements were conducted with Raman spectroscopy, atomic force microscopy and nanoindentation. The latter was used to obtain Young’s modulus as well as Martens and Vickers hardness. The roughness of the film was measured by atomic force microscopy and its thickness was measured. It was shown with Raman spectroscopy that the films are homogeneous in terms of atomic composition and layer thickness over an area of about 125 × 125 mm. Furthermore, it was demonstrated that inverted plasma fireballs are a viable tool for obtaining homogeneous, large area carbon films with rapid growth and very little energy consumption. The obtained films show very low roughness.
        4,000원
        215.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The ultrasonic method is an alternative to the conventional route to produce structured carbon materials, offering the advantages of synthesis in a short period of time under room temperature. The main objective of this work is to synthesize a sulfonated mesoporous carbon catalyst from a phenolic resin composed of phloroglucinol and formaldehyde. The synthesis was performed by the soft-template method in an ultrasonic processor and the product was subsequently carbonized and sulfonated for application in the esterification model reaction. Functionalization with sulfuric acid of MCS5-6 h sample brought about a decrease in porosity but simultaneously resulted in the generation of functional groups of an acidic nature. The MCS5-6 h catalyst with a sulfonic density of 1.6 mmol g− 1, surface area of 402 m2 g− 1 and pore diameter of 10.6 nm maintained in mesoporous even after acid treatment. MCS5-6 h showed excellent activity in the esterification reaction with 95% oleic acid conversion. The recyclability of MCS5-6 h was satisfactory during five reaction cycles. The present work addressed a promising alternative for the synthesis of carbon catalysts using ultrasound irradiation, thus providing an alternative with a lower cost of time and energy for large-scale production.
        4,600원
        216.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lead sulfide ( PbS ) nanocrystals anchored on nitrogen-doped multiwalled carbon nanotubes ( CNx ) have been synthesized employing an environmentally friendly and inexpensive wet chemistry process. CNx∕PbS composites have been examined by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. Theorical ab initio calculations have been developed to determine the samples structural, morphological and optical properties to explain the experimental evidences. The PbS nanoparticles exhibit of 4 nm to 27 nm particle size with a face-centered cubic crystal structure and are homogeneously distributed along the carbon nanotubes. The nitrogen-doped CNTs acts as binding sites for the PbS clusters as ab initio theoretical study suggests.
        4,000원
        217.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon nanotube fiber is a promising material in electrical and electronic applications, such as, wires, cables, batteries, and supercapacitors. But the problem of joining carbon nanotube fiber is a main obstacle for its practical development. Since the traditional joining methods are unsuitable because of low efficiency or damage to the fiber structure, new methods are urgently required. In this study, the joining between carbon nanotube fiber was realized by deposited nickel–copper doublelayer metal via a meniscus-confined localized electrochemical deposition process. The microstructures of the double-layer metal joints under different deposition voltages were observed and studied. It turned out that a complete and defect-free joint could be fabricated under a suitable voltage of 5.25 V. The images of the joint cross section and interface between deposited metal and fiber indicated that the fiber structure remained unaffected by the deposited metal, and the introduction of nickel improved interface bonding of double-layer metal joint with fiber than copper joint. The electrical and mechanical properties of the joined fibers under different deposition voltages were studied. The results show that the introduction of nickel significantly improved the electrical and mechanical properties of the joined fiber. Under a suitable deposition voltage, the resistance of the joined fiber was 37.7% of the original fiber, and the bearing capacity of the joined fiber was no less than the original fiber. Under optimized condition, the fracture mode of the joined fibers was plastic fiber fracture.
        4,500원
        218.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hydroxyl radical (OH radical) is the most harmful free radical amongst the Reactive Oxygen Species (ROS) responsible for numerous diseases of DNA damage like mutagenesis, carcinogenesis and ageing. Therefore, it is important to find a suitable scavenger for OH radical. In the present contribution, we aim to investigate the ability of pristine armchair-SWCNT and B/N/P-doped armchair-SWCNT to scavenge OH radicals using DFT calculations. The calculations reveal that the B/Pdoped armchair-SWCNTs can act as a better scavenger for OH radical compared to pristine armchair-SWCNT but N-doped armchair-SWCNT does not act as a better scavenger for OH radical compared to pristine armchair-SWCNT. Furthermore, the developed scavenger is examined in terms of large-scale availability, biocompatibility, conductivity, stability and reactivity. For both in vivo and in vitro studies, the work is found to useful for enhancing SWCNT as a free radical scavenger.
        4,800원
        219.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서 Nematus tibialis를 국내에서 처음으로 보고한다. 이 종의 사진과 진단, 색 변이, 발육 단계와 분포 등을 제공하였다.
        4,000원
        220.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electro-Fenton (EF) process was first proposed in 1996 and, since then, considerable development has been achieved for its application in wastewater treatment, especially at lab and pilot scale. After more than 25 years, the high efficiency, versatility and environmental compatibility of EF process has been demonstrated. In this review, bibliometrics has been adopted as a tool that allows quantifying the development of EF as well as introducing some useful correlations. As a result, information is summarized in a more visual manner that can be easily analyzed and interpreted as compared to conventional reviewing. During the recent decades under review, 83 countries have contributed to the dramatic growth of EF publications, with China, Spain and France leading the publication output. The top 12 most cited articles, along with the top 32 most productive authors in the EF field, have been screened. Four stages have been identified as main descriptors of the development of EF throughout these years, being each stage characterized by relevant breakthroughs. To conclude, a general cognitive model for the EF process is proposed, including atomic, microscopic and macroscopic views, and future perspectives are discussed.
        5,200원