검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 1,892

        62.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report a simple procedure to fabricate single crystals 3D C60 having an FCC structure on silicon substrates using a vapour–solid set-up in vacuum conditions. The morphology of the deposited film can be tuned by controlling the temperature and position of the substrate. The as-fabricated samples are extensively characterised by transmission electron microscopy, scanning electron microscope, X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation, which allow us to shed light on the recrystallization process of the C60. In addition, the growth mechanism of the formation of crystalline 3D structure of the C60 film is discussed in detail. Based on the newly gained knowledge of mechanism and its unique properties, fullerene has shown huge potential as a solid lubricant on various kinds of substrates.
        4,000원
        64.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Processing and characterization of graphene (Gr)-reinforced aluminium alloy 7075 (AA7075) microcomposites and nanocomposites are reported in this work. Composites are fabricated by mechanical alloying process at wet conditions. The bulk composites are prepared by uniaxial die pressing to get higher densification and sintered in an inert atmosphere. Density of the nanocomposites is higher than the microcomposites due to the reduction of grain size by increased milling time. X-ray diffraction (XRD) analysis confirms graphene interaction with the AA7075 matrix lattice spaces. The effective distribution of graphene with aluminium alloy is further confirmed by the Transmission Electron Microscopy (TEM) analysis. The hardness of the composites proportionally increases with the graphene addition owing to grain refinement. Wear morphology is characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Microcomposites reveal abrasive and ploughing wear mechanism of material removal from the surface. Nanocomposites show adhesive wear with delamination and particle pull-out from the material surface.
        4,300원
        65.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper presents a Raman spectroscopy study of the influence of methane flow on the micro-tribological behavior of diamond-like carbon coatings deposited with an industrial plasma-enhanced chemical vapor deposition system. Results have shown a direct relationship between the methane flow and thickness of the coatings. The analysis of the Raman spectra and deposition parameters allowed establishing the influence of H content with the methane flow, the disorder level and estimation of the sp3 fraction on the carbon coatings. The micro-tribology tests showed a strong dependence of the wear resistance and hardness with Raman parameters. The coating deposited at 72-sccm methane flow presented a thickness of 1.7 μm and a sp3 fraction of 0.33. This sp3 fraction gave rise to a hardness of 24 GPa and an excellent wear resistance of 3.3 × 10–6 mm3 N−1 mm−1 for this DLC coating. Wear tests showed a swelling in the wear profiles on this coating, which was associated with the occurrence of a re-hybridization process.
        4,000원
        66.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        양배추는 짐바브웨 소규모 농가의 음식, 영양 및 소득원으로서 가장 중요한 엽채류 중의 한가지이다. 본 연구에서는 2종의 한국산 양배추 품종(K5 적보라색과 K8 녹색)이 짐바브웨의 열대성 기후에 적응이 가능한지 확인하고자 현지 생산 품종인 Fabiola과 생산성(yield), 조숙성(earliness) 및 연도 (tenderness) 등의 특성 비교 실험을 실시하였다. 본 실험은 2017년 짐바브웨 과학산업연구개발센터(SIRDC, Scientific Industrial Research and Development Center)의 시험포장에서 격리 상태로 5반복 실험으로 진행되었다. 1. 품종별 재배 기간은 현지 품종인 Fabiola가 85-90일, K5 품종이 120-140일 및 K8 품종이 100-120일 정도였다. 2. 양배추 두부 무게는 K8가 Fabiola와 K5 품종에 비하여 유의적으로 무거운 것으로 나타났다(P<0.05). 흥미로운 점은 K5 품종의 경우 타 품종에 비하여 무게가 2-3배 적었다. 3. K8은 35 ton/ha로서 K5의 18과 Fabiola의 25에 비하여 유의적으로 높은 판매 가능한 양배추 생산성이 있는 것으로 확인되었다(P<0.05). 이상의 결과를 종합해보면 K8과 K5 두 한국 양배추 품종 의 생산성, 재배기간 및 품질 특성 등을 현지 품종인 Fabiola 와 비교한 결과 열대성 기후인 짐바브웨에서도 재배가 가능하며 상품성 또한 가지고 있다고 사료된다.
        4,000원
        67.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The nutritional value and yield of mushrooms depend on the substrate on which it is grown. This study sought to biofortify Pleurotus floridanus with calcium supplements and assess its effect on the yield and calcium levels. The experiment was set up in a 2 × 5 factorial and replicated thrice in a completely randomized design. Two calcium supplements, OML and OMW, were added to two growth media. The examination of total dry weight yield showed that calcium supplements OML and OMW in the sawdust medium containing wheatbran in the ratio 1:10 had a mean value of 4.37 g, which was significantly higher (P < 0.05) than that in the control (1.29 g). However, in the sawdust-only medium, there was no significant difference (p > 0.05) in the application of treatments. No significant difference (p > 0.05) was observed between the calcium types in both growth media. The mineral analysis showed that calcium levels were increased in harvested mushrooms with the addition of calcium OML and OMW to the growth media.
        4,000원
        68.
        2020.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the discovery of a giant exoplanet in the microlensing event OGLE-2017-BLG-1049, with a planet―host star mass ratio of q = 9.53 ± 0.39 × 10-3 and a caustic crossing feature in Korea Microlensing Telescope Network (KMTNet) observations. The caustic crossing feature yields an angular Einstein radius of θE = 0.52 ± 0.11 mas. However, the microlens parallax is not measured because the time scale of the event, tE ≃ 29 days, is too short. Thus, we perform a Bayesian analysis to estimate physical quantities of the lens system. We fi nd that the lens system has a star with mass Mh = 0.55+0.36 -0.29 M⊙ hosting a giant planet with Mp = 5.53+3.62 -2.87 MJup, at a distance of DL = 5.67+1.11 -1.52 kpc. The projected star{planet separation is aㅗ = 3.92+1.10 -1.32 au. This means that the planet is located beyond the snow line of the host. The relative lens{source proper motion is μrel ~ 7 mas yr-1, thus the lens and source will be separated from each other within 10 years. After this, it will be possible to measure the flux of the host star with 30 meter class telescopes and to determine its mass.
        4,000원
        80.
        2020.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Two commonly used ceramics in molten salt research are alumina and mullite. The two ceramics were exposed to a combination of rare earth chlorides (YCl3, SmCl3, NdCl3, PrCl3, and CeCl3; each rare earth chloride of 1.8 weight percent) in LiCl-KCl at 773 K for approximately 13 days. Scanning electron microscopy with wave dispersion spectra was utilized to investigate a formation layer or deposition of rare earths onto the ceramic. Only the major constituents of the ceramics (Al, Si, and O2) were observed during the wave dispersion spectra. X-ray fluorescence was used as well to determine concentration changes in the molten salt as a function of ceramic exposure time. This study shows no evidence of ionic exchange or layer formation between the ceramics and molten chloride salt mixture. There are signs of surface tension effects of molten salt moving out of the tantalum crucible into secondary containment.
        4,000원
        1 2 3 4 5