1,721,109 research outputs found
Marina e colonie : discorso pronunziato in Venezia il 28 maggio 1900 ... / Giovanni Roncagli
Full text linkMarina e colonie : discorso pronunziato in Venezia il 28 maggio 1900 ... / Giovanni Roncagli
Spezia : Tip. di F. Zappa, 1900
44 p. ; 19 c
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
Avalanche Current Waveform Estimated From Electroluminescence in InGaAs/InP SPADs
No full textWe demonstrated that the avalanche current waveform in InGaAs/InP single-photon avalanche diodes (SPADs) can be estimated from the measurement of the electroluminescence emitted by the SPAD itself. We simultaneously acquired and compared both optical and electrical waveforms and we extracted the dependence of avalanche current on electroluminescence, showing that the number of collected photons is almost proportional to the number of carriers flowing through the p-n junction, whereas the excess bias (that sets the electric field in the multiplication region when the avalanche is triggered) has a negligible impact. This non-invasive optical technique for estimating the avalanche current can be used when the electrical measurements of the SPAD current are not feasible
Growths and diffusions for InGaAs/InP single-photon avalanche diodes
No full textIn this paper we discuss some of the main characteristics and limitations of the fabrication process forInGaAs/InP single-photon avalanche diodes. The effects of minimum doping levels during semiconductorgrowths and the influence of wafer miscut on the dopant incorporation are analyzed with the support of experimental measurements on test wafers. The Zinc diffusion process is thoroughly analyzed and herewe present and compare experimental results from diffusion tests at different wafer temperatures andprecursor gas flows. In addition, double Zinc diffusion tests at high and low temperatures are discussed. Finally, the effects of the mask aperture on the Zinc diffusion depth have been measured, showing oppositetrends at high and low diffusion temperatures
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
Fast Active Quenching Circuit for Reducing Avalanche Charge and Afterpulsing in InGaAs/InP Single-Photon Avalanche Diode
No full textWe characterize three different quenching circuits for InGaAs/InP single-photon avalanche diodes (SPADs) operated in gated mode: i) a simple passive quenching circuit; ii) an active quenching circuit; and iii) a fast active quenching circuit. For each of these, we acquire the shape of the avalanche current, at different excess biases, by reconstructing the waveform of the photons emitted from the detector during an avalanche and we simultaneously measure the afterpulsing probability and the dependence of dark count rate on gate period (to estimate the maximum count rate). We prove that the avalanche charge reduction is in agreement with the reduction of afterpulsing probability, giving a four-time decrease in afterpulsing when employing the fast active quenching circuit compared to the simple passive quenching circuit
Design Criteria for InGaAs/InP Single-Photon Avalanche Diode
No full textWe provide a detailed insight on the design of InGaAs/InP single-photon avalanche diode (SPAD) for 1.55- μm photon detection. In order to lower SPAD noise [the dark count rate (DCR)] without lowering photon detection efficiency (PDE) or increasing afterpulsing, it is important to optimize detector vertical layer structure and diffusion profiles. We present simulations of SPAD structures with different models, including custom ones. We discuss the influences of multiplication region thickness and doping, absorption region thickness, and electric-field distribution on SPAD performance. Multiplication region thickness strongly affects tunneling generation, whereas a thicker absorption region gives higher absorption efficiency but reduces trigger efficiency. Their optimal values depend on InP and InGaAs material quality and on device operating conditions. We show how electric field within InGaAs must be chosen as a tradeoff between heterobarrier transit efficiency and carrier generation
Dark Count Rate Dependence on Bias Voltage During Gate-OFF in InGaAs/InP Single-Photon Avalanche Diodes
No full textWe characterized the dependence of the dark count rate (DCR) of InGaAs/InP single-photon avalanche diodes on the bias voltage during the OFF time when operated in gated mode. When the OFF bias voltage is too low, there is a strong increment of DCR particularly at temperatures . Measurements of DCR at different gate periods show that this effect is not related to afterpulsing, but to primary carrier generation. We infer that it is due to trapping at the heterobarrier and subsequent release of holes thermally generated in the InGaAs layer
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