通过关键词查论文: Copper (Cu)

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作者: Yasumitsu Kondo
摘要: Copper and nickel are accumulated in steels when steel scrap is used as steel sources. It is well known that copper causes hot shortness problem and nickel suppresses the effect of copper. In this paper, the behaviour of copper and nickel during oxidation is investigated. Steels containing copper and nickel were oxidized and the distribution of copper and nickel in the scale was examined. It was found that copper is not only enriched at the scale/metal interface but also exists in upper magnetite layer as a state of solid solution and along grain boundaries of the wustite layer as metal phase. From these results an assumption has been proposed that the liquid copper migrates from the scale/metal interface to the magnetite layer along the grain boundaries. On the other hand, nickel enriched in steel side near the scale/metal interface with copper. The metal particles containing nickel and copper remain inside the scale. Nickel also has an effect of the uneven scale/metal interface formation.
53
作者: B.M. Rosales, A. Fernández, E. Ayllón, E.N. Codaro, F.E. Varela, Jorge R. Vilche
543
作者: S.M. Myers, D.M. Follstaedt, D.M. Bishop
1635
作者: R. Maria Pérez, A. Abalos, José Manuel Gómez, Domingo Cantero
摘要: The study describes the sorption of Cr, Cu, Mn and Zn by Pseudomonas aeruginosa AT18 isolated from a site contaminated with petroleum and heavy metals. The concentrations studied (mgL-1) were Cr-50, Cu-49, Mn-60 and Zn-70. The solution pH and ionic strength were very important factors in the metal biosorption performance and the biosorption capacity of Pseudomonas aeruginosa AT18 for Cr3+ Cu2+, Mn2+ and Zn2+. In aqueous solution the biosorption increased with increasing pH in the range 5.46-7.72. The results obtained in the experimental assays show that Pseudomonas aeruginosa AT18 has the capacity for biosorption of the metallic ions Cr3+, Cu2+ and Zn2+ in solutions, although its capacity for the sorption of manganese is low (22.39 mg Mn2+/g of biomass) in comparison to the Cr3+, Cu2+ and Zn2+ ions, as shown by the individual analyses. However, 20% of the manganese was removed from an initial concentration of 49.0 mgL- 1, with a Qm value similar to that obtained in solutions containing mixtures of Cr3+ Cu2+, Mn2+ and Zn2+. The chromium level sorbed by Pseudomonas aeruginosa AT18 biomass was higher than that for Cu, Mn and Zn, with 100% removal in the pH range 7.00-7.72 and a Qm of 121.90-200.00 mg of Cr3+/g of biomass. The remove of Cr, Cu and Zn are a result also of precipitation processes.
615
作者: Y. Le Petitcorps, J.M. Poueylaud, L. Albingre, B. Berdeu, P. Lobstein, Jean François Silvain
327
作者: Hendrik Weidmueller, Thomas Weissgaerber, Thomas Hutsch, R. Huenert, T. Schmitt, K. Mauthner, J. Schulz-Harder
摘要: Electronic packaging involves interconnecting, powering, protecting, and cooling of semiconductor circuits for the use in a variety of microelectronic applications. For microelectronic circuits, the main type of failure is thermal fatigue, owing to the different thermal expansion coefficients of semiconductor chips and packaging materials. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers. The advantages of carbon nanofibers, especially the good thermal conductivity, are utlized to obtain a composite material having a thermal conductivity higher than 400W/mK. The main challenge is to obtain a homogeneous dispersion of carbon nanofibers in copper. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed. In order to improve the bonding strength between copper and nanofibers, different alloying elements were added. The microstructure and the properties will be presented and the influence of interface modification will be discussed.
853
作者: Salete S. Balula, Luís Cunha-Silva, Isabel C.M.S. Santos, Filipe A. Almeida Paz, João Rocha, Helena I.S. Nogueira, Ana M.V. Cavaleiro
摘要: Mono-substituted and sandwich-type copper substituted polyoxoanions ([PW11CuO39]5− and [Cu4(H2O)2(PW9O34)2]10−) were studied as catalysts for the epoxidation of cyclooctene and geraniol, using the green oxidant H2O2, with the results suggesting good efficiency at room temperature. High selectivity and reasonable conversion data were found after the first minutes of reaction. The copper centre may be responsible for this performance and our on-going research focuses in the preparation of new materials incorporating copper into polyoxometalates (POMs). In this context, we have also isolated a new crystalline dimeric sandwich-type polyoxocoppertungstate {H7.05[Cu3WO(H2O)(CuW9O34)(Cu0.6W9O34)]}7.75−. This compound was isolated as potassium salt and structurally characterized by FTIR and single-crystal X-ray diffraction (XRD). The polyoxoanion is composed by the [CuW9O34]12− and [Cu0.6W9O34]12.8− anionic fragments, joined together by a rhomb-like arrangement of three Cu2+ and one W6+ metallic centres, all exhibiting octahedral coordination geometries.
538
作者: Ji Whan Ahn, Hee Chan Cho, Kwang Suk You, Gi Chun Han, Nam Il Um
摘要: Most carbonation processes utilizing municipal solid waste incineration bottom ash characteristically involve a high water content (over 100%). In this work, we developed an improved carbonation process, utilizing various water contents. In addition, we investigated the characteristics of a carbonation reaction using municipal solid waste incinerator bottom ash as a function of water content and their effects on the stabilization of copper and lead. As a result of such a carbonation reaction, the effect on the stabilization of heavy metals can be obtained. Due to this, the leaching concentrations of these were reduced. In a high water content, calcium aluminum compounds via carbonation reaction adsorbed Cu and Pb ions. Where a low water content (especially 30%) is present, particle surfaces are surrounded by calcium aluminum compounds of bottom ash as a result of the carbonation process. The leaching concentration of Cu and Pb were decreased through the carbonation process.
533
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