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        검색결과 131

        43.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We measured the non-carbon content of single-walled carbon nanotubes (SWCNTs) in SWCNT soot using thermogravimetric analysis. The weight increased percentage by the oxidation of metal in the raw soot is well obtained by TGA graph which was confirmed with ICP-AES, XRD, and XPS. This work will be very useful for the purity precise evaluation of SWCNT with UN-vis-NIR spectroscopy.
        3,000원
        45.
        2006.09 구독 인증기관·개인회원 무료
        Bend tests were performed at temperatures between 77 and 473K for W-19vol%Cu, W-22vol%Ag and W-19vol%(BAg-8) composites. Yield and maximum strengths and ductility of the composite were discussed in terms of microstructure and fractography. Results are summarized as follows. (1) Almost no difference was recognized in yield strength between the composites. In contrast, a large difference was recognized in maximum strength and ductility between the composites. (2) Inferior mechanical properties of W-Ag composite to W-Cu composite are attributed to heterogeneous distribution of Ag-phases, whilst inferior mechanical properties of W-(BAg-8) composite to W-Cu composite are attributed to large pores at grain boundaries.
        46.
        2006.09 구독 인증기관·개인회원 무료
        Ti-Cu-Ni-Sn quaternary amorphous alloys of Ti50Cu32Ni15Sn3, Ti50Cu25Ni20Sn5, and Ti50Cu23Ni20Sn7 composition were prepared by mechanical alloying in a planetary high-energy ball-mill (AGO-2). The amorphization of all three alloys was found to set in after milling at 300rpm speed for 2h. A complete amorphization was observed for Ti50Cu32Ni15Sn3 and Ti50Cu25Ni20Sn5 after 30h and 20h of milling, respectively. Differential scanning calorimetry analyses revealed that the thermal stability increased in the order of Ti50Cu32Ni15Sn3, Ti50Cu25Ni20Sn5, and Ti50Cu23Ni20Sn7.
        47.
        2006.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Phosphoric acid-activated carbon WP's and zinc chloride-activated carbons WZ's were developed from wild cherry stones. The textural properties of the activated carbons were determined from nitrogen adsorption data at 77 K and the chemistry of the carbon surface, i.e. the surface carbon-oxygen groups (type and amount) was determined from the base and acid neutralization capacities (Boehm method). The adsorption of phenol, p-nitrophenol, p-chlorophenol, dinitrophenol and dichlorophenol was followed at 298 K. The activated carbons obtained were characterized by high surface area and large pore volumes as well as by high surface concentration of C-O groups. The investigated carbons exhibited high adsorption capacities towards phenols with these capacities increased with the increase of molecular weight and the decrease of the solubility of phenol in water. However, no general relationship could be observed between the adsorption capacities of carbons and any of their textural parameters or their surface chemistry. This may be attributed to the many factors controlling phenol adsorption and the different types and mechanisms of adsorption involved.
        4,000원
        54.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbons were obtained by activating wild cherry stones with different concentrations of phosphoric acid or zinc chloride at different temperatures. The adsorption of N2 at 77 K and of CO2 at 273 K was followed and the data were analyzes by considering different adsorption models. The activated carbons obtained measured high surface area with the most of the surface in all samples located in micropores. Fair agreement was found between the nitrogen surface areas calculated from the BET-, t-, α- and DR- methods, although the first three are based on surface coverage whereas the latter is based on micropore filling. The carbon dioxide surface areas calculated by the DA equation were smaller than the comparable nitrogen areas. This was ascribed to domination of surface coverage mechanism, the absence of activated diffusion process. Based on this explanation the CO2-surface areas as calculated by DA equation should be taken with great reservation.
        4,000원
        60.
        2005.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Cosmic Evolution Survey (COSMOS) is a Hubble Space Telescope (HST) treasury project. The COSMOS aims to perform a 2 square degree imaging survey of an equatorial field in I(F814W) band, using the Advanced Camera for Surveys (ACS). Such a wide field survey, combined with ground-based photometric and spectroscopic data, is essential to understand the interplay between large scale structure, evolution and formation of galaxies and dark matter. In 2004, we have obtained high-quality, broad band images of the COSMOS field (B, V, r', i', and z') using Suprime-Cam on the Subaru Telescope, and we have started our new optical multi-band program, COSMOS-21 in 2005. Here, we present a brief summary of the current status of the COSMOS project together with contributions from the Subaru Telescope. Our future Subaru program, COSMOS-21, is also discussed briefly.
        3,000원
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