1,721,138 research outputs found
New catalysts for acetylene polymerisation
No full textThe salts [NMe4]2[Ni5(CO)12], [NMe4]2[Ni6(CO)12], [NMe4]2[Ni12(CO)21H2] and [NEt4]3[Ni12(CO)21H] in acetone are efficient catalysts for the polymerisation of acetylene
Disegno – Laboratori del primo anno
No full textIl volume illustra l’attività condotta all’interno dei Laboratori del disegno tenuti presso la Facoltà del Design del Politecnico di Milano. Prendendo a riferimento l’a.a. 2000/2001, esso non si configura come testo didattico quanto, piuttosto, come rendiconto di una sperimentazione didattica che ha progressivamente portato ad affiancare all’insegnamento tradizionale del disegno forme di rappresentazione non grafiche (fotografia, modellistica ecc), per approdare, attraverso gli anni, all’attuale formula del laboratorio multidisciplinare. Collocati al primo anno del corso di studi, tali laboratori propongono pertanto un approccio complessivo ai problemi della rappresentazione, privilegiando una metodologia didattica di tipo induttivo e tenendo conto delle specificità che l’insegnamento del disegno presenta in una scuola di design rispetto ad una facoltà di architettura o di ingegneria
A new approach to the synthesis of cobalt and iron carbide carbonyl clusters by CO cleavage
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
PHYSICAL-PROPERTIES OF METAL CLUSTER COMPOUNDS .1. MAGNETIC MEASUREMENTS ON HIGH-NUCLEARITY NICKEL AND PLATINUM CARBONYL CLUSTERS
No full textMetal-carbonyl cluster compounds are composed of macromolecules that consist of a core of metal atoms coordinated by a "shell" of CO ligands. We present susceptibility and high-field magnetization measurements on various high-nuclearity platinum and nickel clusters. The compounds display very unusual low-temperature magnetic behaviour, which we ascribe to quantum-size-effects arising from the discreteness of the electronic energy levels due to the small dimensions of the metal clusters (10-40 atoms). We compare our results with predictions from molecular orbital calculations
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