1,720,984 research outputs found
Diamond and diamond-like carbon MEMS
No full textDiamond and diamond-like carbon (DLC) thin films possess a number of unique and attractive material properties that are unattainable from Si and other materials. These include high values of Young's modulus, hardness, tensile strength and high thermal conductivity, low thermal expansion coefficient combined with low coefficients of friction and good wear resistance. As a consequence, they are finding increasing applications in micro-electro-mechanical systems (MEMS). This paper reviews these distinctive material properties from an engineering design point of view and highlights the applications of diamond and DLC materials in various MEMS devices. Applications of diamond and DLC films in MEMS are in two categories: surface coatings and structural materials. Thin diamond and DLC layers have been used as coatings mainly to improve the wear and friction of micro-components and to reduce stiction between microstructures and their substrates. The high values of the elastic modulus of diamond and DLC have been exploited in the design of high frequency resonators and comb-drives for communication and sensing applications. Chemically modified surfaces and structures of diamond and DLC films have both been utilized as sensor materials for sensing traces of gases, to detect bio-molecules for biological research and disease diagnosis
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
MEMS based digital variable capacitors with a high-k dielectric insulator
No full textA novel MEMS based digital variable capacitor was designed and fabricated. The device consists of a multi-cantilever (or bridge) with variable length, suspended over a bottom electrode. By applying a voltage between the electrodes, the electrostatic force pulls the beams in one-by-one, realizing a digital increase in capacitance. A high-k dielectric HfO2 is also introduced to increase the capacitance value and tuning range. These devices were fabricated by a four-mask process, and electrical tests have confirmed the stepwise increase of the capacitance with bias. However it was found that it is difficult to pull-in more than 10 cantilevers and most of the cantilevers remained on the substrate when the bias is off. Charge injection from the pulled-in electrode into the insulator increases the pull-in voltage drastically, and prevents pulling-in more cantilevers. Trapped charges in the insulator produce an electrostatic force and keep the cantilever stuck on the substrat
Modelling and fabrication of low operation temperature microcages with a polymer/metal/DLC trilayer structure
No full textMulti-finger microcages with metal/diamond like carbon (DLC) bilayer and polymer/metal/DLC trilayer structures were analyzed, simulated and fabricated. Modelling by finite element analysis showed that a soft polymer can be used together with DLC to form a normally closed microcage which can be opened by 90 degrees angle at a temperature of similar to 400 K, which is much lower than that of a metal/DLC bilayer structure previously demonstrated. The opening temperature for a microcage is independent of the finger dimensions, but is simply determined by the thermal expansion coefficient difference of two materials used. Microcages with SU8/DLC bilayer and SU8/Al/DLC trilayer structures have been fabricated and fully closed microcages with diameters of similar to 40 mu m have been obtained. Initial electrical tests have showed these devices open by more than 90 degrees at a temperature lower than 150 degrees C, roughly in agreement with the theoretical analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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