1,720,980 research outputs found
A thermal actuator for nanoscale in-Situ microscopic testing: design and characterization.
No full textThis paper addresses the design and optimization of thermal actuators
employed in a novel MEMS-based material testing system. The testing
system is designed to measure the mechanical properties of a variety
of materials/structures from thin films to one-dimensional structures,
e.g. carbon nanotubes (CNTs) and nanowires (NWs). It includes a thermal
actuator and a capacitive load sensor with a specimen in-between. The
thermal actuator consists of a number of V-shaped beams anchored at both
ends. It is capable of generating tens of milli-Newton force and a few
micrometers displacement depending on the beams’ angle and their number.
Analytical expressions of the actuator thermomechanical response are
derived and discussed. From these expressions, a number of design criteria
are drawn and used to optimize the device response. The analytical
predictions are compared with both finite element multiphysics analysis
(FEA) and experiments. To demonstrate the actuator performance,
polysilicon freestanding specimens cofabricated with the testing system are
tested
An analysis of the membrane deflection experiment used in the investigation of mechanical properties of freestanding submicron thin films
No full text
Predictions of strength in MEMS components with defects - a novel experimental-theoretical approach
No full textGoing 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
An analysis of the membrane deflection experiment used in the investigation of mechanical properties of freestanding submicron thin films
No full textAbstractIn this paper we investigate, both experimentally and theoretically, the competition between different failure mechanisms (stretching, bending and curvature localization) in freestanding submicron thin films commonly used in micro-electromechanical systems. Microstructures made of elastic-brittle materials such as ultrananocrystalline diamond, diamond like carbon and silicon nitride, as well as elastic–plastic materials such as gold, aluminum, and copper, are tested by means of the membrane deflection experiment developed at Northwestern University. Evidence of competition between different failure modes has been found for the investigated elastic-brittle materials. The phenomenon is dependent on specimen size and shape. By contrast, in the case of elastic–plastic materials, failure due to stretching was found to be the dominant mechanism. An analytical model is proposed to rationalize the experimental data and to provide dimensionless parameters able to describe the competition between different failure mechanisms. These dimensionless parameters are particularly useful in the design of specimens employed in the MDE technique
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