1,720,987 research outputs found
Electric Field Properties of CdTe Nuclear Detectors
No full textRecently, diode-like In/CdTe/Pt detectors have been realized which look very promising thanks to their enhanced spectroscopic performance. Scope of this work is to investigate the electric field distribution inside these detectors and its temporal evolution by means of the Pockels effect. The implemented set-up allows us to map the electric field and thus to extract the field profiles between the contacts. The analysis shows that the field is mainly confined below the anode. After applying the bias, these detectors are not very stable at room temperature, and they present a pronounced degradation in spectroscopic performance. This degradation is correlated in this work to the evolution of the electric field which has been observed to ‘move’ towards the anode. We attribute this ‘polarization’ behavior in CdTe detectors to the concomitance of two factors: the presence of deep levels in the bulk material, and the high hole barrier height of In on CdTe
Charge Transients by Variable Wavelength Optical Pulses in CdTe Nuclear Detectors
Full text linkWe study charge transients induced by optical pulses in CdTe detectors. Different carrier dynamics and collection properties are observed in the signals induced by optical excitation in the wavelength range 500–1650 nm, depending on the absorption and on the transport mechanism involved. A systematic comparison between charge transients, by irradiation through cathode and anode contacts, allows to point out the role of defects near the surface, instability effects, deep level transitions into the bulk, and internal photoelectric effects at the contacts
Charge Transients by Variable Wavelength Optical Pulses in CdTe Nuclear Detectors
No full textCharge transients induced by optical pulses in CdTe detectors are used to investigate carrier dynamics and collection properties. Various features have been observed in the signals induced by optical excitation in the wavelength range 500nm - 1650nm, depending on the absorption, and the transport mechanism involved. A systematic comparison between charge transients recorded for irradiations through cathode and anode contacts, allows to point out the role of defects near the surface, instability effects, deep level transitions into the bulk, and finally internal photoelectric effects at the contacts
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
Dual ion-beam sputtering deposition of palladium-fluoropolymer nano-composites
No full textThe morphological (TEM) and chemical (XPS, ARXPS) characterizations of fluoropolymer films modified with palladium particles (CFx(Pd)) are reported in this article. The films, which have different levels of metal content, have been deposited by ion beam co-sputtering a Teflon target and a palladium one. Composite films with a thickness of a few nanometers have also been deposited and analyzed. For all degrees of thickness, the analyses show the fluoropolymer nature of the hosting material, the nanoscopic character of metal domains, and their uniform distribution in the polymer matrix. The likely application of this ion sputter-deposited material in the sensor field has also been preliminary tested
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
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