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        검색결과 12

        4.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The (Ga1-xZnx)(N1-xOx) solid solution is attracting extensive attention for photocatalytic water splitting and wastewater treatment owing to its narrow and controllable band gap. To optimize the photocatalytic performance of the solid solution, the key points are to decrease its band gap and recombination rate. In this study, (Ga1-xZnx)(N1-xOx) nanofibers with various Zn fractions are prepared by electrospinning followed by calcination and nitridation. The effect of the composition and crystallinity of electrospun oxide nanofibers on the morphology and optical properties of the obtained solid-solution nanofibers are systematically investigated. The results show that the final shape of the (Ga1-xZnx) (N1-xOx) material is greatly affected by the crystallinity of the oxide nanofibers before nitridation. The photocatalytic properties of (Ga1-xZnx)(N1-xOx) with different Ga:Zn atomic ratios are investigated by studying the degradation of rhodamine B under visible light irradiation.
        4,000원
        6.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report on an all-solution-processed hydrothermal method to control the morphology of ZnO nanostructures on Si substrates from three-dimensional hemispherical structures to two-dimensional thin film layers, by controlling the seed layer and the molar contents of surfactants during their primary growth. The size and the density of the seed layer, which is composed of ZnO nanodots, change with variation in the solute concentration. The ZnO nanodots act as heterogeneous nucleation sites for the main ZnO nanostructures. When the seed layer concentration is increased, the ZnO nanostructures change from a hemispherical shape to a thin film structure, formed by densely packed ZnO hemispheres. In addition, the morphology of the ZnO layer is systematically controlled by using trisodium citrate, which acts as a surfactant to enhance the lateral growth of ZnO crystals rather than a preferential one-dimensional growth along the c-direction. X-ray diffraction and energy dispersive X-ray spectroscopy results reveal that the ZnO structure is wurtzite and did not incorporate any impurities from the surfactants used in this study.
        4,000원
        7.
        2016.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Flower-like nickel oxide (NiO) catalysts were coated on NiCrAl alloy foam using a hydrothermal method. The structural, morphological, and chemical bonding properties of the NiO catalysts coated on the NiCrAl alloy foam were investigated by field-emission scanning electron microscopy, scanning electron microscopy-energy dispersive spectroscopy, Xray diffraction, and X-ray photoelectron spectroscopy, respectively. To obtain flower-like morphology of NiO catalysts on the NiCrAl alloy foam, we prepared three different levels of pH of the hydrothermal solution: pH-7.0, pH-10.0, and pH-11.5. The NiO morphology of the pH-7.0 and pH-10.0 samples exhibited a large size plate owing to the slow reaction of the hydroxide (OH−) and nickel ions (Ni+) in lower pH than pH-11.5. Flower-like NiO catalysts (~4.7 μm-6.6 μm) were formed owing to the fast reaction of OH− and Ni2+ by increased OH− concentration at high pH. Thus, the flower-like morphology of NiO catalysts on NiCrAl alloy foam depends strongly on the pH of the hydrothermal solution.
        4,000원
        9.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 거대고리 금속 이온 착화합물과 유도체를 이용하여 미세 다공성 구조를 가지는 분리막의 제조에 관한 것이다. 고분자와 금속이온 리간드 착물 시스템을 이용함으로써 기존의 방법들에 비해 상 전이 과정을 보다 정교하게 제어할 수 있었다. 금속염, cyclohexanedione dioxime, hydroxyphenylboronic acid와의 축합 반응을 통하여 금속 clathrochelate 착물을 얻을 수 있었다. PES, PVP, BE와 금속 clathrochelate 착물을 DMF에 녹인 후 비용매 유도 상 전이법을 통하여 유무기 혼성 고분자막을 제조하였다. 제조된 분리막의 구조는 FE-SEM과 microflow permporometer로 조사하였다. p-Hydroxyphenyl group 을 가지는 Fe(II) clathrochelate 착물의 첨가는 분리막의 구조에 있어 기공 크기 분산도를 좁혀주고, 표면의 기공 밀도를 높여 주었으며 최대 기공 크기를 감소시킴을 볼 수 있었다.
        4,300원
        10.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Monodispersed flaky silver powder was obtained by controlling the ratios of and Agin in a mixed solution of ethylene glycol and ammonia with an addition of PVP. The effects of on its morphology and size were investigated. In molar ratio was found to be an important reaction factor for the nucleation and crystal growth of Ag powder. The synthesis of flaky powder was optimized at over 6 of molar ratio increased, the size of precipitates was increased regardless of the amount of Pt. In the absence of , the morphology and size of reduced Ag powder were found to be irregular in shape in diameter. However, homogenized fine Ag powder was obtained due to heterogeneous nucleation when used as a cat-alyst, and flaky one was synthesized with the addition of Pt over of Pt/Ag.
        4,000원
        11.
        2002.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        토마토녹응애(개칭)에 대해 주사전자현미경 관찰, 국내 분포, 기주식물, 온도에 따른 발육상, 약제 방제법에 관하여 연구하였다. 토마토녹응애는 2쌍의 다리를 가진 길이 의 미소동물로 feathered claw는 4줄이었다. 피해증상으로, 피해엽은 적갈색으로 변하고 줄기에는 털이 없어지고 광택이 나거나 표면이 그물형으로 갈라지며, 새순은 시들거나 위축된다. 과일은 과경 부근에 그을음이나 녹이 긴 것 같이 되고, 그물형으로 갈라진다. 충남의 부여와 유성, 강원도 평창, 경북의 칠곡, 구룡포의 유리온실에서 발견되었으며, 한국에서 기주로는 메꽃, 까마중, 가지, 꽈리, 나팔꽃, 페투니아, 감자, 고추, 담배, 토마토 등이 확인되었다. 이 응애는 에서 발육이 가능하였고, 한 세대는 6-11일로 높은 온도일수록 발육기간이 짧아지는 경향이었으며, 암컷이 수컷보다 수명이 길었는데, 25-28에서 12일로 가장 수명이 길었다. 살비제 중에서 fenazaquin과 cypermethrin의 효과가 가장 좋았다.
        4,000원