1,721,092 research outputs found
RESOLVING THE SURFACE CONTRIBUTION OF THE P L2, 3 VV AUGER LINESHAPE OF GAP(110) VIA USE OF (1 X-1) SB OVERLAYERS
No full textAn experimental and theoretical study of the band-like P L2,3VV Auger lineshape for GaP(110) is reported (kinetic energy almost-equal-to 120eV). By deposition of one monolayer of Sb (isoelectronic to P) we determine the surface-related Auger lineshape as the difference between the two spectra measured from the as-cleaved surface and the GaP/Sb interface. Theoretical calculations based on a single particle approach including different structural coordination models (i.e. ideally truncated surface, real relaxed surface, ordered Sb overlayer) are performed, which allows to isolate the surface contribution of the L2,3VV Auger profile from the bulk related lineshape. Moreover the results of the joint analysis are discussed giving excellent agreement between calculations and measurements and pointing toward an interpretation of the P LVV lineshape in terms of surface structural probe
EXPERIMENTAL AND THEORETICAL SURFACE COMPONENT OF THE PL2,3VV AUGER LINESHAPE IN GAP(110) - THE USE OF ORDERED (1X1) SB OVERLAYERS
No full textAn analysis of the theoretical and experimental surface contribution of the PL2,3VV Auger lineshape in GaP(110) is performed. From the theoretical point of view the lineshapes are calculated within a single-particle framework from a slab-by-slab tight-binding calculation of the ideal and real relaxed surfaces. The experimental information is extracted by comparing the Auger feature of as-cleaved GaP(110) and of the GaP(110) interfaced with one ordered monolayer of Sb. This allows the LVV surface component to be isolated. A comparison with theory, showing strong similarities in the position of the surface-related features is discussed
Experimental and theoretical-study of the PL2,3VV auger lineshape of GaP(110)
No full textA joint experimental and theoretical investigation of the PL2,3VV Auger transition on GaP(110) is presented. The theoretical data, calculated within a pure band-like picture, are compared to the experimental spectra. The angular momentum character of the five features constituting the lineshape is identified. Strong contributions to the experimental data from many-body effects may be ruled out due to the good overall agreement with the theoretical lineshape therefore supporting a single particle description for this Auger feature. We discuss effects such as Coulomb correlation, initial state core hole screening, self-energy corrections, that may possibly contribute to the relative energy shifts observed in one of the pp components of the compared spectra
Strong chemical-reactivity at the early stages of YB overgrowth on GAP(110) - A synchrotron-radiation study
No full textAngle resolved XPS characterization of cationic polyacrylamides
No full textIn many applications surfaces are modified using polymer films and the polymers used are often complex copolymers. In biomedical applications it is critical to determine the surface properties of a substrate as it is these that mediate the cellular interactions. The surface structure of copolymer films can only rarely be established from their bulk composition alone. In this study angle resolved XPS was used to build a model of the structure of copolymer films produced on glass substrates from a family of poly(acrylamide) copolymers containing cationic blocks. The thickness of the copolymer films was demonstrated to be dependent on the concentration of the polymer solution and the ratio of non-cationic to cationic blocks in the copolymer. The data demonstrated that the cationic blocks of the copolymer preferentially segregated to the glass surface and the non-cationic poly(acrylamide) blocks preferentially segregated to the air-vacuum interface. A low concentration of the cationic functional groups was present throughout the poly(acrylamide) layer and it was suggested that this resulted from a small fraction of the cationic blocks being pulled into the poly(acrylamide) layer at points along the polymer chain where the two blocks are connected. Evidence of a thin surface hydrocarbon contamination layer was also observed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
QUENCHING THE SURFACE ELECTRONIC-STRUCTURE OF P-CONTAINING-III-V SEMICONDUCTORS VIA ORDERED (1X1) SB OVERLAYERS - A PL2,3VV AUGER LINE-SHAPE ANALYSIS
No full textWe report experimental PL2,3VV Auger line shapes of as-cleaved GaP(110) and InP(110) surfaces and of the relative Sb p(1 x 1) interfaces along with calculated slab-resolved densities of states (DOS). The joint experimental and theoretical analysis allows us to disentangle the surface-specific PL2,3VV contribution from the total signal of the as-cleaved surfaces
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