1,721,032 research outputs found
Photluminescence properties of orgainic-inorganic sol-gel films doped with semiconductor quantum dots
No full textHybrid organic-inorganic thin films doped with lead sulfide nanocrystallites were synthesized by a combination of colloidal chemistry and sol-gel processing. In order to study the influence on the spectroscopic properties of the crystallite surface, and hence the related defect states, PbS-doped films with different sulfur to lead ratios and different surface capping agent concentrations were fabricated. X-ray diffraction measurements showed the presence of nanoparticles with a mean diameter raging from 3 to 5 nm. The absorption spectra showed a large blue shift of the absorption edge to shorter wavelength, indicating strong quantum confinement. Strong photoluminescence emission in the near infrared was found by pumping at 514 or 532 nm. The emission intensity and its position were found to be dependent on the elaboration parameters. The film fabrication process influences only slightly the good particle size distribution of the colloidal PbS solutions. Best results were obtained for films with low sulfur to lead ratio or with high capping agent concentration
Monteleone M. 2015. Reshaping agriculture toward a transition to a post-fossil Bioeconomy. In: Law and Agroecology - A Transdisciplinary Dialogue. Editors: Monteduro M., Buongiorno P., Di Benedetto S., Isoni A. p. 359-376. Publisher: Springer-Verlag Berlin Heidelberg. ISBN: 978-3-662-46616-2P
No full text
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
Dispositivo concentratore di luce solare per un sistema di generazione fotovoltaica
No full textIn un sistema di generazione fotovoltaica avente una pluralità di celle fotovoltaiche, un dispositivo concentratore di luce solare è dotato di una pluralità di unità ottiche, che sono provviste di rispettivi concentratori primari a superficie curva composta presentanti, ciascuno, una apertura di entrata per l'ingresso diretto della luce solare, una apertura di uscita per l'uscita della luce solare concentrata verso una rispettiva cella fotovoltaica e un asse ottico attraversante l'apertura di entrata e di uscita, e che sono affiancate tra loro con gli assi ottici paralleli tra loro per definire una apertura di entrata complessiva per la luce solare, e ciascuna delle aperture di entrata definisce, su di un piano ortogonale agli assi ottici, un contorno di entrata sagomato in modo tale per cui l'apertura di entrata complessiva sia completamente coperta dall'insieme delle aperture di entrata
- …
