1,721,083 research outputs found
Utilizzo di algoritmi algebrici per l'applicazione della tomografia ai controlli non distruttivi
No full textMessa a punto di una tecnica di tomografia interferometrica
No full textMediante la tecnica di ricostruzione tomografica si è misurato l'indice di rifrazione all'interno di una barretta di Pyrex. La misura è stata fatta utilizzando l'interferometria olografica in tempo reale. Si è rilevata con tale tecnica la differenza di cammino ottico fra lo spessore della barretta e un liquido, la glicerina, avente indice di rifrazione noto e molto simile al campione. Sono stati realizzati dodici interferogrammi secondo diverse angolazioni e a partire da questi si è ricostruita la distribuzione dell'indice di rifrazione all'interno del volume con la tecnica tomografica
Applicazione della tecnica tomografica nella sperimentazione meccanica: elaborazione e rappresentazione 3D dei risultati
No full textSome applications of tomography to te experimental mechanics are show. In particular the value of the refractive index inside a Pyrex bar is studied. The authors point out that the techniques, used for interpolation and 3D restitution inside the material volume, make easy the analysis of whole data
Monolithic Silicon-Based Nanobeam Cavities for Integrated Nonlinear and Quantum Photonics
Full text linkPhotonic resonators that allow an electromagnetic field to be confined in an ultrasmall volume with a long decay time are crucial to a number of applications requiring enhanced nonlinear effects. For applications to integrated photonic devices on chip, compactness and optimized in-plane transmission become relevant figures of merit as well. Here we optimize an encapsulated Si/SiO2 photonic-crystal nanobeam cavity at telecom wavelengths by means of a global optimization procedure, where only the first few holes surrounding the cavity are varied to decrease its radiative losses. This strategy allows us to theoretically achieve intrinsic quality factors close to 10 million, sub-diffraction-limited mode volumes, and in-plane transmission above 65%, in a structure with a very small footprint of about 8 mu m(2). We address and quantitatively assess the dependence of the main figures of merit on the nanobeam length and on fabrication disorder. Finally, we study a system of two optimized and laterally coupled nanobeam cavities with the goal of demonstrating an unconventional photon blockade at room temperature in a monolithic passive device. We estimate the single-photon nonlinearity of this device and discuss the relevant figures of merit, which lead to sub-Poissonian photon statistics of the transmitted signal. Our results hold promise for prospective experiments in low-power nonlinear and quantum photonics
Photonic crystal slab cavity simultaneously optimized for ultra-high Q/V and vertical radiation coupling
No full textWe present a design for a two-dimensional photonic crystal slab cavity in which the electric field localization is due to an extra hole in the lattice, as opposed to the more standard procedure of removal of holes. This leads to a tighter field confinement and a mode volume that is several times smaller than that of conventionally used designs. Through small modifications of the holes around the cavity, we optimize the theoretical quality factor (Q) to an ultra-high value of 20.9 x 10(6) and furthermore illustrate the possibility for high coupling efficiency to free-space modes in the vertical direction, while keeping a high Q of 3.7 x 10(6). Published by AIP Publishing.LTP
Impaired lactation performance following elective delivery at term: role of maternal levels of cortisol and prolactin.
No full textObjective: Lactation performance depends on stress surrounding labor and delivery, and it is likely to be different in women who underwent elective cesarean delivery (ECD) or vaginal (VD). The aim of this study was to assess the relationship between cortisol and human prolactin (hPRL), following ECD and lactation performance, from the delivery room to the 6th month of life. Methods: A total of 106 mothers were consecutively enrolled: 38 after ECD, 28 after emergency cesarean delivery (EmCD), and 40 after VD. Results: Basal stress-, lactogenic-hormones, cortisol, and hPRL were comparable on day 3 postpartum in all the women. Multivariate analysis indicated that ECD has a negative impact (OR; 95% CI) on breastfeeding prevalence on the seventh day (0.14; 0.00.44, p0.008) and at third month post partum (0.19; 0.050.71, p0.05) in comparison to VD. In addition, hPRL levels proved to have a statistically significant role in early breastfeeding (1.01; 11.01, p0.002). Conclusions: ECD is a risk factor for successful lactation performance. This information should be provided to mothers and caregivers for extra breastfeeding guidance. © 2012 Informa UK, Ltd
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
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