1,721,082 research outputs found
Conductivity, responsivity and noise in photoconductive devices. Development and check of a novel theory
No full textDependence of photoconduction noise on temperature: A check of barrier-type theory of photoconductivity in CdS based devices
No full textPhotoinduced space charge effect on current noise in photoconducting insulators
No full textABSTRACTA set of experimental measurements concerning both current noise and conductance relaxation curves in CdS and CdSe photoconductors has shown the existence of a relationship between the noise power spectrum and the Fourier transform of the phototransient curve. Some of these experimental results have already been published. It appears that at least two different noise components contribute to the total power spectrum. The first component, which dominates the low frequency part of tile spectrum, is strictly related to the behaviour of the relaxation curve. Indeed, it can be attributed to the fluctuation of the photoinduced positive trapped charge and consequently of the potential barrier at the interface electrode-photoconductive material. The second component, on the contrary, is practically independent of the light wavelength, and represents an intrinsic noise component related to the generation-recombination and trapping processes within the photoconductor. In this paper we present a theory accounting for both the photoinduced and the intrinsic noise component. This theory fits well to the experimental data concerning the dependence of noise on light intensity and wavelength, using the parameters obtained from the phototransient and photoconductance measurements performed on thle same specimens. It also gives tile correct order of magnitude of the measured absolute value of the noise power spectrum.</jats:p
A cline for glyoxalase i allele frequencies in Italy
No full textA gradient of glyoxalase I allele frequencies is described in Italian populations. The association between longitude and allele frequency is assessed through simple and multiple correlation, and gene flow is suggested as a major factor in the origin of such a pattern. © 1986 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted
Excess current noise in quantum well infrared photodetectors
No full textThe excess noise with respect to the simple shot noise is calculated for a single quantum well. device characterized by a modulation mechanism of the current transport process at the emitter potential barrier. The effect of the negative space charge on the noise is taken into account and it is shown that it acts as a smoothing factor for the shot noise but it is not influent on the excess noise generated by the barrier fluctuations
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
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