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        검색결과 8

        1.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        10 wt.% and 20 wt.%Li-TiO2 composite powders are synthesized by a sol-gel method using titanium isopropoxide and Li2CO3 as precursors. The as-received amorphous 10 wt.%Li-TiO2 composite powders crystallize into the anatase-type crystal structure upon calcination at 450oC, which then changes to the rutile phase at 750oC. The asreceived 20 wt%Li-TiO2 composite powders, on the other hand, crystallize into the anatase-type structure. As the calcination temperature increases, the anatase TiO2 phase gets transformed to the LiTiO2 phase. The peaks for the samples obtained after calcination at 900oC mainly exhibit the LiTiO2 and Li2TiO3 phases. For a comparison of the photocatalytic activity, 10 wt.% and 20 wt.% Li-TiO2 composite powders calcined at 450oC, 600oC, and 750oC are used. The 20 wt.%Li-TiO2 composite powders calcined at 600oC show excellent efficiency for the removal of methylorange
        4,000원
        2.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nano Pd spot-coated active carbon powders were synthesized by a hydrothermal-attachment method (HAA) using PVP capped Pd colloid in a high pressure bomb at , 450 psi, respectively. The PVP capped Pd colloid was synthesized by the precipitation-redispersion method. PVP capped Pd nano particles showed the narrow size distribution and their particle sizes were less than 8nm in diameter. In the case of nano Pd-spot coated active carbon powders, nano-sized Pd particles were adhered in the active carbon powder surface by HAA method. The component of Pd was homogeneously distributed on the active carbon surface.
        4,000원
        3.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper introduces an effect of a preparing -Ag composite on its mechanical properties and microstructure. In present study, -Ag was prepared by reduction-deposition route and wetting dispersive milling method, respectively. Two type of Ag powders (nano Ag and micron Ag size, respectively) were dispersed into powder during wetting dispersive milling in D.I. water. Each sample was sintered at for 2hr in atmosphere, and then several mechanical tests and analysis of microstructure were carried out by bending test, hardness, fracture toughness and fracture surface microstructure. As for microstructure, the Ag coated showed homogeneously dispersed Ag in in where pore defect did not appear. However, -nano Ag and -micro Ag composite appeared Ag aggregation and its pore defect, which carried out low mechanical property and wide error function value.
        4,000원
        4.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ag spot-coated Cu nanopowders were synthesized by a hydrothermal-attachment method (HA) using oleic acid capped Ag hydrosol. Cu nano powders were synthesized by pulsed wire exploding method using 0.4 mm in diameter of Cu wire (purity 99.9%). Synthesized Cu nano powders are seen with comparatively spherical shape having range in 50 nm to 150 nm in diameter. The oleic acid capped Ag hydrosol was synthesized by the precipitation-redispersion method. Oleic acid capped Ag nano particles showed the narrow size distribution and their particle size were less than 20 nm in diameter. In the case of nano Ag-spot coated Cu powders, nanosized Ag particles were adhered in the copper surface by HAA method. The components of C, O and Ag were distributed on the surface of copper powder.
        4,000원
        5.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A visible-light photoactive photocatalyst was synthesized successfully by means of cogrinding of anatase- in ambient, followed by heat-treatment at in air environment. In general, it is well known that the grinding-operation induces phase transformation of a- to rutile . This study investigates the influence of the amount of gas on the phase transformation rate of a- and enhancement of visible-light photocatalytic activity, and also examines the relation between the photocatalytic activity and the period of grinding time. The phase transformation rate of a- to rutile is retarded with the amount of NH3 injected. And the visible-light photocatalytic activity of samples, was more closely related to the period of grinding time than amount injected, which means that the doping amount of nitrogen into more effective to mechanical energy than amount injected. XRD, XPS, FT-IR, UV-vis, Specific surface area (SSA), NOx decomposition techniques are employed to verify above results more clearly.
        4,000원
        6.
        2008.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nano-sized TiO2-60 wt% SrO composite powders were synthesized by a sol-gel method using titanium isopropoxide and Sr(OH)2 · 8H2O as precursors. 3, -5, -7 wt%Ag spot-coated TiO2-60 wt% SrO composite powders were synthesized by a Ag electroless deposition method using TiO2-60 wt% SrO composite powders calcined at 1050˚C, which mainly exhibited the SrTiO3phase. However, a small number of rutile TiO2, Sr2TiO4 and SrO2 phases were also detected. In the Ag spot-coated powders synthesized by electroless deposition, nano-sized particles about 5-25 nm in diameter adhered to the TiO2-60 wt% SrO composite powders. The photocatalytic activity of Ag spot-coated TiO2-SrO and TiO2-SrO composite powders for degradation of phenol showed that all of TiO2-SrO composite powders were highly active under UV light irradiation. 7 wt%Ag spot-coated TiO2-60wt.%SrO composite powders had a relatively higher photocatalytic activity than did TiO2-SrO composite powders under visible light.
        4,000원
        7.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Using the nano Fe powders having 50 nm in diameter, Fe compact bodies were fabricated by injec-tion molding process. The relationship between microstructure and material properties depending on the volume ratio of powder/binder and sintering temperature were characterized by SEM, TEM techniques. In the compact body with the volume percentage ratio of 45(Fe powder) : 55(binder), which was sintered at the relative density was about and the values of volume shrinkage and hardness were about and 242.0 Hv, respec-tively. Using the composition of 50(Fe powder) : 50(binder) and sintered at the values of relative density, volume shrinkage and hardness of Fe sintered bodies were and 152.8 Hv, respectively. They showed brittle fracture mode due to the porous and fine microstructure.
        4,000원
        8.
        2003.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ni coated composite was successfully Prepared by the electroless deposition Process. The average size of Ni particles coated on the matrix powder was about 20 nm. It was hard to find any reaction compound as an impurity at interface between and Ni particles after sintering. The characterization of microstructure crystal structure and fracture behavior of the sintered body were investigated using XRD, TEM and Victors hardness tester, and compared with those of the sintered monolithic body. Many dislocations were observed in the Ni phase due to the difference of thermal expansion coefficient between and Ni phase, and no observed microcracks at their and Ni interface. In the /Ni composite, the main fracture mode showed a mixed fracture with intergranular and transgranuluar type having some ,surface roughness. The fracture toughness was slightly increased due to the plastic deformation mechanism of Ni phase in the /Ni composite.
        4,000원