1,720,959 research outputs found
Materiali fotoattivi nanostrutturati: sintesi, caratterizzazioni e applicazioni.
Get PDFTitanium dioxide is suitable to answer some important needs of our society, particularly in the environmental field, as a photo catalyst, and in the energy field, for realization of devices for a rational use of solar energy. Thanks to nanotechnology, this material has found a renewed interest by the scientific community for innovative properties that occur as a result of its nanoscale.
The materials based on titanium dioxide produced in this work were obtained by sol-gel method, which is now one of the most studied techniques for the synthesis of nanostructured materials. The interest stimulated by this method is its extreme versatility and advantages of ease of control of process parameters. Specifically, samples were synthesized containing either only titanium dioxide, or inorganic hybrid silica / titania.
The reasons that led to the trial presented here lie in understanding the influence of experimental parameters (composition, temperature, time) that govern the synthesis process on nature and structural characteristics of the material isolated. Morphology, crystallinity and micro-structure, have been investigated by X-ray Powder Diffraction (XRPD), Nitrogen Physisorption, Atomic Force Microscope (AFM) and Debye Function Analysis (DFA). We also correlated the effect of experimental and structural aspects on the functional properties (photocatalytic activity) of the synthesized materials.
Another important aspect of this work concerns the investigation of the application of the materials produced for the surface modification of textile substrates (polyester) in order to obtain "smart textiles" that can effectively reduce environmental pollutants. In this area we investigated the effects of variation of process parameters on the performance exhibited by functionalized textiles
Testing the Debye Function Approach on a Laboratory X-ray Powder Diffraction Equipment. A Critical Study.
Get PDFCrystals: Structure and Microstructure of Nanocrystals Using the Debye Function Analysis
No full textSynthesis and solid state structure of thermally stable linear bi–pyrazoles
No full textThe long and rigid bi-pyrazolyl-based ligands 2,6-bis[4-(1H-pyrazol-4-yl)phenyl]pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetrone, L1, and 2,5-bis[4-(1H-pyrazol-4-yl)phenyl]thiazolo[5,4-d]thiazole, L2, were isolated in pure form, with satisfying yields, as very insoluble polycrystalline materials. Their thermal behavior was investigated by coupling thermal analyses and variable-temperature X-ray powder diffraction measurements. Their crystal structures were unraveled from powder diffraction data by a rather unconventional structure determination approach, without the a priori knowledge of the unit cell parameters. Inline with shorter analogues, successfully employed in the formation of porous MOFs with intriguing functional properties, L1 and L2 are promising to construct higher-porosity materials, potentially capable of hosting nano-sized guests
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Investigating the amorphous–crystalline interplay in SiO2/TiO2 nanocomposites by total scattering methods
No full textA combined real- and reciprocal-space total scattering approach was realized by applying Debye and radial distribution functions to nanocrystalline and amorphous fractions within the same experimental pattern. The method allows for the quantitative description of micro-structural features induced by the amorphous–crystalline interplay in silica–titania nanocomposites
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
L'attivita' economica pubblica e la concorrenza: profili applicativi degli articoli 90 del Trattato di Roma ed 8 della Legge 287/90
No full textDottorato di ricerca in diritto dell'economia. 6. ciclo. Tutore C. AngeliciConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
- …
