1,720,957 research outputs found
Organolanthanide(II) Chemistry: Synthesis and Structure of [Cp*Sm(-OC)2FeCp*]2
No full textThe tetranuclear complex [Cp Sm(-OC)2FeCp ]2 (3) has been prepared by reaction of Cp 2Sm(THF)2 with [Cp Fe(CO)2]2 and structurally characterized by single-crystal X-ray diffraction
Diiminophosphinate des Lithiums, Samariums und Ytterbiums: Moleku¨lstrukturen von Li[Ph2P(NSiMe3)2](THF)2 und [Ph2P(NSiMe3)2]2Sm(μ-I)2Li(THF)2
No full textDie Molekülstruktur von Li[Ph2P(NSiMe3)2](THF)2 (2) wurde durch Röntgenstrukturanalyse bestimmt. Ein viergliedriger LiNPN-Ring bildet die zentrale Einheit des monomeren Moleküls. YbI2 reagiert mit zwei Äquivalenten Li[Ph2P(NSiMe3)2] (1) zum neuartigen Ytterbium(II)diiminophosphinat [Ph2P(NSiMe3)2]2Yb(THF)2 (3). Die analoge Reaktion von 1 mit SmI2 liefert das Samarium(III)derivat [Ph2P(NSiMe3)2]2Sm(μ-I)2Li(THF)2 (4), dessen Struktur ebenfalls röntgenographisch bestimmt wurde. Abstract: The molecular structure of Li[Ph2P(NSiMe3)2](THF)2 (2) has been determined by an X-ray diffraction study. A four-membered LiNPN ring forms the central unit of the monomeric molecule. YbI2 reacts with two equivalents of Li[Ph2P(NSiMe3)2] (1) to give the novel ytterbium(II)diiminophosphinate [Ph2P(NSiMe3)2]2Yb(THF)2 (3). A similar reaction of 1 with SmI2 affords the samarium(III) derivative [Ph2P(NSiMe3)2]2Sm(μ-I)2Li(THF)2 (4) whose structure has also been determined by an X-ray diffraction study
Monomere Organosamarium(III) Chalkogenolate durch reduktive Spaltung von E–E-Bindungen (E = S, Se, Te)
No full textDas THF-Addukt des Decamethylsamarocens, Cp2 Sm(THF)2, reagiert mit Disulfiden, Diseleniden und Ditelluriden zu Organosamarium(III)komplexen, die eine Sm–E-Bindung enthalten (E = p. Se, Te). Die Molekülstrukturen der Komplexe Cp2 Sm(S2CNMe2) (1), Cp2 Sm[TeC6H2Me3-2,4,6](THF) (4) und Cp2 Sm[SeC6H2(CF3)3-2,4,6](THF) (5) wurden röntgenographisch bestimmt. Abstract: The THF adduct of decamethylsamarocene, CP2Sm(THF)2, reacts with disulfides, diselenides and ditellurides to give organosamarium(III) complexes containing a Sm---E bond (E = S, Se, Te). The molecular structures of the complexes CP2Sm(S2CNMe2) (1), Cp2Sm[TeC6H2Me3-2,4,6](THF) (4) and Cp2Sm[SeC6H2(CF3)3-2,4,6](THF) (5 have been determined by X-ray diffraction
Alkoxysilylamide des Neodyms, Samariums und Ytterbiums: Viergliedrige anorganische Ringsysteme in der Lanthanidchemie
No full textLi[Me2Si(OtBu)(NtBu)] (1) reagiert mit YbI2 zum Ytterbium(II)alkoxysilylamid [Me2Si(OtBu(NtBu)]2Yb(THF)2 (2). Die analoge Reaktion von 1 mit SmI2 liefert das Samarium(III)derivat [Me2Si(OtBu)(NtBu)]2Sm(μ-I)2Li(THF)2 (3). Däruber hinaus wird die Darstellung von [Me2Si(O)tBu)(NtBu)] Nd (4) und [Me2Si(OtBu)(NtBu)]2Yb(μ-Cl)2Li(THF)2 (5) beschrieden. Die Molekülstrukturen von 4 und 5 wurden röntgenographisch bestimmt. Abstract: Li[Me2Si(OtBu)(NtBu)](1) reacts with YbI2 to give the ytterbium(II)alkoxysilylamide [Me2Si(OtBu)-(NtBu)]2Yb (THF)2 (2). The analogous reactio of 1 with SmI2 yields the samarium(III) derivative [Me2Si(OtBu)(NtBu)]2Sm(μ-I)2Li(THF)2 (3). Moreover, the preparation of [Me2Si(OtBu)(NtBu)]3Nd (4) and [Me2Si(OtBu)(NtBu)]2Yb(μ-Cl)2Li(THF)2 (5) is described. The molecular structures of 4 and 5 have been determined by X-ray crystallography
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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