1,720,958 research outputs found
Effects of temperature/humidity treatments on the peel strength of CuCr alloy films on polyimide
No full textA single layer of CuCr alloy was sputter deposited on polyimide films instead of Cu/Cr double layers. The adhesion strengths of the metal/polyimide thin films were measured by the peel test. In order to study the effects of temperature and humidity on the adhesion strength, 85 degrees C/85% R.H. (T/H) treatments were applied to the specimens. Results showed that the peel strength without T/H treatments increased proportionally with the Cr content in the CuCr alloy layer (x) up to 17 at %, and then saturated. Among the samples studied, the peel strength decreased with hold time under T/H conditions for all the cases, but most drastically for the sample with x = 8.5. The very poor peel strength of that sample (x = 8.5) was attributed to the occurrence of interfacial failures, which were thought to take place along CuCr oxide/polyimide interfaces
Effects of heat treatment at 350 degrees C on the adhesion of Cu-Cr alloy films to polyimide
No full textCuCr alloys with varying Cr content were sputter deposited on polyimide films, and the metal/polyimide films were maintained under 350 degrees C/N-2 environment up to 10 hours for the reliability measurements. The Cr contents of the alloy layer prepared were 0, 8.5, 17, 25, 34, and 100 atomic %, respectively. Before exposures to 350 degrees C, the peel strength increased proportionally with the Cr content in the alloy layer up to 17 atomic % and saturated. The failure occurred inside polyimide near the metal/polyimide interface by the cohesive failure mode except for the specimen with no Cr. After exposures to 350 degrees C, the peel strength dropped for all the specimens, but most drastically for the specimens with 8.5% Cr which failed along the Cr-oxide/polyimide interface by the interfacial failure mode. Through AES and XPS analyses, it was shown that the decrease of the peel strength during the heat treatment was primarily caused by the formation of brittle Cr2O3 at the metal/polyimide interface, which was accompanied by the reduction of carbidic bonds responsible for the good adhesion. (C) 2000 Kluwer Academic Publishers
Adhesion behavior of CuCr alloy/polyimide films under 350 degrees C and 85 degrees C/85% RH environments
No full textCuCr alloys with varying Cr content were sputter-deposited onto polyimide films and the metal/polyimaaide films were exposed to a 350 degrees C/N-2 environment for up to 10 h or to 85 degrees C/85% relative humidity (RH) (T/H) conditions for up to 840 h for reliability measurements. The Cr contents of the alloy layers (x) prepared were 0, 2.5, 8.5, 17, 25, 34, and 100 atomic %. Before exposure to hostile environments, the peel strength increased proportionally with the Cr content in the alloy layer up to x=17 and saturated around 550 J/m2, and failure occurred within the polyimide near the metal/polyimide interface, except for the specimen with no Cr (x=0). After exposure to 350 degrees C, the peel strength dropped for all specimens, but most drastically for the specimens with lower Cr contents (x=8.5) which failed along the Cr-oxide/polyimide interface. The general trend was the same in the case of the T/H treatment, where interfacial failure along the CuCr-oxide/polyimide interface was found far the specimens with lower Cr content (x less than or equal to 17). The extent of interfacial failure over the peeled metal surfaces was found to increase with the T/H treatment time and was inversely related to the peel strength
Cohesive failure of the Cu/polyimide system
No full textThe cohesive failure which occurs in the inside of the polymer near the metal/polymer interface was studied in the Cu:Cr/polyimide and Cu/CuCr/polyimide systems. The interface energy was varied by pretreating the polyimide surface by varying rf plasma power density, or by varying the Cr content in the CuCr alloy layer, respectively, and peel tests were conducted. Then, peeled metal strips were analyzed by AES and XPS, and correlations were made among the peel strength, the amount of carbide-like Cr-C bonds near the interface, and the polyimide thickness on peeled metal films inferred from the AES depth profiling. Results indicate that the peel strength increased with the rf power density at a constant metal thickness and that the thickness of polyimide adhering to peeled metal films increased with the peel strength, which was related to the amount of carbide-like Cr-C bond near the interface affecting the interface energy. In the case of specimens with the same plasma treatment but various metal layer thickness, the thickness of polyimide on peeled metal films remained constant even though the peel strength increased with the metal layer thickness. (C) 2000 Elsevier Science S.A. All rights reserved
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
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