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        검색결과 3,043

        221.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study assessed the utility of netted melon ‘Top Earl’s’ and cantaloupe melon ‘Alex’ as functional fruits by analysing their moisture content, vitreous sugar, folic acid, citric acid, and beta-carotene levels. High-performance liquid chromatography (HPLC) was used to analyse the free sugar, folic acid, citric acid, and beta-carotene levels. The moisture content was not significantly different between ‘Top Earl’s’ and ‘Alex.’ The glucose, sucrose, and fructose contents were three, two, and one-and-a-half fold higher in ‘Alex’ than in ‘Top Earl’s.’ Moreover, citric acid was approximately three times higher in ‘Alex’ than that in Top Earl’s.’ However, the folic acid content was higher in ‘Top ‘Earl’s’ than ‘Alex,’ and the amount was 124 μg / 100 g FW and 112 μg / 100 g FW respectively. ‘Beta-carotene was undetectable in ‘Top Earl’s,’ whereas it was 1000 μg / 100 g FW in ‘Alex.’ β-carotene, a substance that is converted in the body into vitamin A and acts as an antioxidant, is an important component in healthy food. These results suggested that the cantaloupe melon ‘Alex’ has a higher free sugar content and functional ingredients, such as antioxidants, including citric acid and beta carotene, than the netted melon ‘Top Earl’s.’
        4,000원
        222.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With a strive to develop light-weight material for automotive and aerospace applications, aluminum-based hybrid nanocomposites (AHNCs) were manufactured utilizing the compocasting approach in this study. Chopped carbon fibers (CFs) are reinforced along with different weight fractions of nanoclay (1–5%) in the matrix of AA6026 forming AHNCs. The AHNCs specimens were examined by microstructural analysis, mechanical characterization, fatigue, and corrosion strength as per ASTM guidelines. Electroless plating method is adopted for coating CFs with copper to improve the wettability with matrix. SEM pictures of manufactured composites reveal thin inter-dendritic aluminum grains with precipitate particle of eutectic at intergranular junctions, as well as nanoclay particles that have precipitated in the matrix. Tensile strength (TS) rises with inclusion of nanoclay up to a maximum of 212.46 MPa for 3% nanoclay reinforcement, after which the TS is reduced due to non-homogeneity in distribution, agglomeration and de-bonding of nanoparticles. Similarly, micro-hardness increases with addition of 3% nanoclay after which it decreases. Higher energy absorption was achieved with 3% nanoclay reinforced hybrid and a significant improvement in flexural strength was obtained. With addition of both CFs and nanoclay, the fatigue strength of the hybrid composite tends to increase due to flexible CFs and high surface area nanoclays which strengthen the grain boundaries until 3% addition. Addition of nanoclay lowers the corrosion rate with nanoclays filling the crevices and voids in the matrix.
        4,600원
        223.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Here, we report the preparation of microporous-activated carbons from a Brazilian natural lignocellulosic agricultural waste, cupuassu shell, by pyrolysis at 500 ºC and KOH activation under different experimental conditions and their subsequent application as adsorbent for CO2 capture. The effect of the KOH:precursor ratio (wt/wt%) and the activation temperature on the porous texture of activated carbons have been studied. The values of specific surface area ranged from 1132 to 2486 m2/ g, and the overall micropore volume ranged from 0.73 to 1.02 cm3/ g. Carbons activated with 2:1 ratio of KOH and activation temperature of 700 ºC presented a CO2 adsorption at 1 bar of 7.8 and 4.4 mmol/g at 0 °C and 25 ºC, respectively. The isosteric heat of adsorption, Qst , was calculated for all samples by applying the Clausius–Clapeyron approach to CO2 adsorption isotherms at both temperatures. The values of CO2 adsorption capacities are among the highest reported in the literature, especially for activated carbons produced from biomass.
        4,000원
        227.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        On January 4, 2020, the official Twitter account of the former US President Trump threatens to target Iran’s cultural heritage sites conditioned on any Iranian retaliation on US military forces then stationed in the Middle East. The immediate context was that the US-led drone strike had killed Iran’s Major General Qasem Soleimani in Iraq (Baghdad) only two days prior. This study critically analyzes whether “Tweets” uploaded to President Trump’s Twitter account could reasonably be construed as a type of harm against international law instruments and framework on the safeguarding of cultural heritage. This paper provides a brief contextual overview of President Trump’s Tweets; traces the historical destruction of cultural property during conflicts and discusses the preservation of heritage; delineates international laws and assesses whether President Trump and the US might be legally bound to refrain from threats to destroy cultural property; and examines the increasing role of social media in the evolution of the idea of diplomacy.
        5,800원
        228.
        2023.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study assessed the influences of fluorine introduced into DLC films on the structural and mechanical properties of the sample. In addition, the effects of the fluorine incorporation on the compressive stress in DLC films were investigated. For this purpose, fluorinated diamond-like carbon (F-DLC) films were deposited on cobalt-chromium-molybdenum substrates using radio-frequency plasma-enhanced chemical vapor. The coatings were examined by Raman scattering (RS), Attenuated total reflectance Fourier transform infrared spectroscopic analysis (ATR-FTIR), and a combination of elastic recoil detection analysis and Rutherford backscattering (ERDA-RBS). Nano-indentation tests were performed to measure hardness. Also, the residual stress of the films was calculated by the Stony equation. The ATR-FTIR analysis revealed that F was present in the amorphous matrix mainly as C-F and C-F2 groups. Based on Raman spectroscopy results, it was determined that F made the DLC films more graphitic. Additionally, it was shown that adding F into the DLC coating resulted in weaker mechanical properties and the F-DLC coating exhibited lower stress than DLC films. These effects were attributed to the replacement of strong C = C by feebler C-F bonds in the F-DLC films. F-doping decreased the hardness of the DLC from 11.5 to 8.8 GPa. In addition, with F addition, the compressive stress of the DLC sample decreased from 1 to 0.7 GPa.
        4,000원