1,721,215 research outputs found
Influence of inert gas pressure on deposition rate during pulsed laser deposition
No full textThe deposition rates of permalloy and Ag are monitored during pulsed laser deposition in different inert gas atmospheres. Under ultrahigh vacuum conditions, resputtering from the film surface occurs due to the presence of energetic particles in the plasma plume. With increasing gas pressure, a reduction of the particle energy is accompanied with a decrease of resputtering and a rise in the deposition rate for materials with high sputtering yield. In contrast, at higher gas pressures, scattering of ablated material out of the deposition path between target and substrate is observed, leading to a decrease in the deposition rate. While in the case of Xe and Ar these processes strongly overlap, they are best separated in He. A He pressure of about 0.4 mbar should be used to reduce the kinetic energy of the deposited particles, to reach the maximum deposition rate and to avoid implantation of the particles. This is helpful for the preparation of stoichiometric metallic alloy films and multilayers with sharp interfaces
Community structure and support network variation in rural areas: a United Kingdom-Netherlands comparison
No full textAlloy-ceramic oxide multilayer mirrors for water-window soft x rays
No full textAlloy-ceramic oxide multilayers of Ni80Nb20-MgO with 3.56-nm period have been made by use of the pulsed-laser deposition technique and characterized by means of grazing-incidence x-ray reflectivity. The interface roughness was found to be only similar to0.35 nm at the two interfaces, Ni80Nb20-MgO and MgO-Ni80Nb20, leading to a peak reflectivity of similar to 38% at the first order. The atomic structure in the two individual layers, Ni80Nb20 and MgO, is found to be amorphous, in agreement with the deposition conditions. These multilayers can be used as mirrors for soft x rays in the angular range 18 degrees to 39 degrees depending on the actual wavelength of radiation in the water-window region. (C) 2001 Optical Society of America
Pulsed laser deposition of metals in various inert gas atmospheres
No full textThe changes in the properties of laser deposited metal thin films were investigated in different inert gas atmospheres (He, Ne, Ar and Xe). With increasing inert gas pressure, the reduction of particle energy is accompanied by a strong increase of the deposition rate (especially in He atmosphere), a transition from compressive to tensile stress, and changes in structure and texture. This is explained by a reduction of surface mobility of the deposited particles, a decrease of implantation, resputtering and shot-peening effects. At high gas pressures, deposition conditions similar to sputtering or even thermal deposition are obtained
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
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