1,721,482 research outputs found
Development of a numerical simulation of depth profiles of multilayers composed of very thin layers
No full textA numerical approach is presented in order to simulate multilayer depth profiles. In many practical cases the normalized measured intensity may be described well by a superimposition of error functions. Here, calculation of the error function has been performed using an approximation formula that allows it to be obtained by a simple but accurate method.Particular attention has been paid to the development of a procedure that can be applied to the fitting of experimental data relative to depth profiling of samples composed of very thin layers
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
Reactions of molybdenum pentachloride with oxygen and nitrogen donor ligands
No full textThe interactions of molybdenum pentachloride (1) with a variety of organic compounds were studied in dichloromethane and the metal products were isolated in the solid state. The 3:1 molar reactions of 1 with OCRR′ (R = R′ = Ph; R = H, R′ = 2-C6H4Me) afforded the complexes Mo(O)Cl3(OCRR′)2 (R = R′ = Ph, 2a; R = H, R′ = 2-C6H4Me, 2b) in high yields. Compound , 3, was isolated in 35% yield from 1 and 2-acetylfuran. The 1:1 reaction of 1 with phenazine (C12H8N2) 1 resulted in the formation of MoCl5(C12H8N2), 4; the oxydo-chloride derivative Mo(O)Cl3[κ1(N)-C12H8N2], 5, was prepared straightforwardly by addition of phenazine to Mo(O)Cl3, formed in situ upon treatment of 1 with tetrahydrofuran. The addition of a twofold excess of Me2NCH2CH2CO2Me to 1 afforded MoCl4[κ1(N)-Me2NCH2CH2CO2Me]2, 6, in 72% yield. The reaction of 1 with MeO2CCtriple bond; length of mdashCCO2Me led to a mixture of inseparable products: MoOCl3(κ1-MeO2CCtriple bond; length of mdashCCO2Me)2, 7a, MoCl5(κ1-MeO2CCtriple bond; length of mdashCCO2Me), 7b, and MoCl4(κ1-MeO2CCtriple bond; length of mdashCCO2Me)2, 7c, were recognized by combined EPR/DFT investigation. Analogous DFT/EPR studies were performed on 2b and 4. The X-ray structures of 2a, 3 and 5 were determined; the X-ray structure of 5 represents a rare example of crystallographically-characterized pentacoordinated Mo(V) neutral complex
Physical properties of TiN thin films
No full textThis paper reports on the characterization of films of titanium nitride (TiN) obtained by reactive sputtering of titanium in a nitrogen-rich ambient (r.f. sputtering) and by nitrogen implantation during vapour deposition of titanium thin films.In order to ger a complete picture of the properties of the atoms in these systems the thin films were charcterized with Auger electron spectroscopy and with a Seeman-Bohlin x-ray diffractometer. The overlayers were analyzed by four-point probe to evaluate the resystivity.The observed chemical and physical properties of the films strongly depend on both the growth technique and the particular parameters employed
One-pot preparation of (n4-alkadiene)dichloroplatinum(II) complexes from [PtCl6]2- and their easy reduction to platinum(0) alkene complexes under phase transfer catalysis conditions
No full textSYNTHESIS AND REACTIVITY OF cis-[PtCl2(RCN)(PPh3)]: USEFUL PRECURSORS TO trans-[PtCl(m-Cl)(PPh3)]2
No full textAuger quantitative analysis and preferential sputtering in brass alloys
No full textThe qualitative and quantitative characterization with Auger Electron Spectroscopy (AES) at the surfaces of bulk brass alloys with different stoichiometry have been carried out. In order to draw out a calibration curve to correlate the measured Auger signals to the true concentrations, the effects of ion bombardment on the surface composition (preferential sputtering) have been studied. The investigation has been performed in a concentration range from 60 to 100%at in Cu. The Auger measurements on clean surfaces have been executed on the alloys surfaces prepared in situ both by scraping and by sputtering with Ar ions. The results show that Zn is preferentially sputtered from the surface respect to Cu
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
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