186,570 research outputs found
Mechanism of nucleophilic attack by secondary anilines on the nitrile group in platinum(II) ortho-cyanobenzyl complexes
No full textMechanism of nucleophilic attack by secondary anilines on the nitrile group in platinum(II) ortho-cyanobenzyl complexes
Il dialetto in poesia. Studio metrico sulla poesia novecentesca del Nord-Italia
No full textQuesta tesi di dottorato si articola attorno alla poesia dialettale contemporanea del Nord-Italia. Si tratta di uno studio metrico delle poesie scritte in diversi dialetti selezionati in base a un sistema linguistico unitario quale il galloitalico che si riscontra in Piemonte, Lombardia, Liguria e Emilia Romagna. Nello specifico, il corpus qui esaminato prende in considerazione le forme poetiche che, nel secondo Novecento, conferiscono al verso libero una certa regolarità come le strutture “semplici” quasi archetipiche delle quartine, delle ottave e di tutte le forme metriche che costituiscono un monoblocco multiplo di quattro in quanto possono nascondere una struttura in quartine spesso svelata dalla rima, dalla sintassi e a volte anche dal ritmo. Queste scelte che potrebbero sembrare arbitrarie sono in realtà legate alle scelte più diffuse dei poeti i quali recuperano spesso delle forme metriche della tradizione per innovarle o semplicemente per riproporle tale quali o con alcune variazioni. I legami con la tradizione e il concetto di libertà nella chiusura sono studiati in rapporto alle componenti fondamentali dell’organismo metrico, vale a dire la forma, le rime, la sillabazione e il ritmo. Si tratta insomma di capire, come dice Raboni, come “la dissonanza può essere usata per «salvare» l’ipotesi tonale” e come “la trasgressione metrica finisce col prolungare la vita della regola alla quale, derivandone, si oppone” (Giovanni RABONI, L’opera poetica, a cura di Rodolfo ZUCCO, Milano, Mondadori, i Meridiani, 2006, p.403). L’obbiettivo di questa ricerca è dunque quello di esplorare e di spiegare l’ambiguità metrica della poesia dialettale
novecentesca tenendo sempre presente un articolo fondamentale per questo tipo di studio scritto da Pier Vincenzo Mengaldo e intitolato Questioni metriche novecentesche. Nelle grandi linee, questa tesi non vuole solo prolungare una riflessione ancora ai suoi inizi nella poesia regionale
contemporanea, ma vorrebbe realizzare un panorama essenziale, benché sommario, che metta in primo piano gli aspetti innovativi e, a volte, conservativi della poesia dialettale contemporanea di alcune regioni del Nord-Italia.This study is articulated around the contemporary dialectal poetry of northern Italy. It is focused on the metric of poems written in different dialects chosen for their linguistic system unity, such as the “galloitalico” that influences the language of the following regions of Northern Italy: Piemonte, Lombardia, Liguria and Emilia Romagna. The corpus selected is organized around specific poetic forms that give the “verso libero” a kind of steadiness in the second half on the twentieth century, such as the “simple” and almost archetypal structures of the “quartine”, the “ottave” and of all other strophes that constitute a multiple of four. These choices that could appear
arbitrary are actually linked to the choices of the poets, who often appropriate the traditional metric canevas to change them, or on the contrary to follow them. The links with the tradition and the concept of liberty into the closing structures are therefore studied in relation to the metric such as the form, the rime, the versification and the rhythm. As Raboni declared, we will understand in this manner how “la dissonanza può essere usata per «salvare» l’ipotesi tonale” and how “la trasgressione metrica finisce col prolungare la vita della regola alla quale, derivandone, si oppone” (Giovanni RABONI, L’opera poetica, a cura di Rodolfo ZUCCO, Milano, Mondadori, i Meridiani, 2006, p.403). The aim of this study is therefore to explore and explain the metrical ambiguity of the contemporary dialectal poetry keeping in mind a central article for studies of this type written by Pier Vincenzo Mengaldo and entitled Questioni metriche novecentesche. This thesis will extend the debate on the regional contemporary poetry still in its infancy, as well as offer an essential even if
brief panorama that puts the innovative and, at times, conservative aspects of the contemporary dialectal poetry of some regions of Northern Italy in the foreground
Optical switching in metal tunnel-insulator n-p+ silicon devices
No full textThis paper considers the mechanism of optical switching and the possible utilisation of the metal tunnel-insulator n-p+ silicon device in optical communication systems. The pertinent design approaches are described. Under optical excitation, photo holes and electrons generated in the surface depletion region, or within diffusion range, will eventually be separated by the electric field and produce an increment in the forward current. Those hole-electron pairs generated in the junction region, or within diffusion range, produce a photovoltaic increase in the p+-n junction bias. Switching is induced optically, as it is electrically, by the build up of holes at the insulator-semiconductor interface. This paper employs the 1-dimensional diffusion equation to derive the light generated minority Carrier distributions and diffusion currents in the neutral n and p+ regions, together with the currents in the surface and p+-n junction depletion regions. The calculated values of both the drift and diffusion currents compare favourably with those observed experimentally
Calcium hydroxylapatite treatment of human skin: evidence of collagen turnover through picrosirius red staining and circularly polarized microscopy
No full textNicola Zerbinati,1 Alberto Calligaro2 1Department of Surgical and Morphological Sciences, University of Insubria (Varese) and Polyspecialist Medical Center, Pavia, 2Department of Public Health, Experimental and Forensic Medicine, Unit of Histology and Embryology, University of Pavia, Pavia, Italy Background: Calcium hydroxylapatite (CaHA, Radiesse®) is a biocompatible, injectable filler for facial soft-tissue augmentation that provides volume to tissues, followed by a process of neocollagenesis for improved skin quality. Objective: To examine the effects of CaHA treatment on the molecular organization of collagen using a combination of picrosirius red staining and circularly polarized light microscopy.Methods: Five subjects received subdermal injection of 0.3 mL of CaHA in tissues scheduled for removal during abdominoplasty 2 months later. Tissue specimens from the CaHA injection site and a control untreated area were obtained from excised skin at the time of surgery. Processed tissue sections were stained with picrosirius red solution 0.1% and visualized under circularly polarized light microscopy for identification of thick mature (type I) and thin newly formed (type III) collagen fibers. Pixel signals from both the control and CaHA-treated areas were extracted from the images, and morphometric computerized hue analysis was performed to provide a quantitative evaluation of mature and newly formed collagen fibers.Results: Under picrosirius red staining and circularly polarized light microscopy, green/yellow areas (thin newly formed collagen type III) were visible among the collagen fibers in tissue sections from the area of CaHA injection. In contrast, the majority of the collagen fibers appeared red (thick mature collagen type I) in control tissues. Morphometric analysis confirmed that, following CaHA treatment, the proportion of fibers represented by thin newly formed collagen type III increased significantly (p<0.01) in comparison with the proportion of thick mature collagen type I fibers. In contrast, collagen content of control tissues consisted almost exclusively of thick mature collagen type I fibers. Conclusion: The use of picrosirius red staining and circularly polarized light microscopy provides evidence that subdermal injection of CaHA stimulates the formation of new collagen and dermal remodeling. Keywords: calcium hydroxylapatite, neocollagenesis, picrosirius red, circularly polarized light microscopy, Radiesse 
Self-adaptive high-frequency injection based sensorless control for interior permanent magnet synchronous motor drives †
No full textAbstract: An auto-tuning and self-adaptation procedure for High Frequency Injection (HFI) based position and speed estimation algorithms in Interior Permanent Magnet Synchronous Motor (IPMSM) drives is proposed in this paper. Analytical developments show that, using conventional approaches, the dynamics of the high-frequency tracking loop varies with differential inductances, which in turn depend on the machine operating point. On-line estimation and adaptation of the small signal gain of the loop is proposed here, allowing accurate auto-tuning of the sensorless control scheme which does not rely on a priori knowledge of the machine parameters. On-line adaptation of Phase-Locked Loop (PLL) gains and of the injected voltage magnitude is also possible, leading to important advantages from the performance, loss and acoustic point of view. The theoretical basis of the method has been introduced first and the main concept demonstrated by means of simulations. Implementation has been carried out using the hardware of a commercial industrial drive and two Interior Permanent Magnet Synchronous Motors, namely a prototype and an off-the-shelf machine. Experimental tests demonstrate the feasibility and effectiveness of the proposal
Recognition of surface flow processes influeced by roads and trails in mountain areas using high-resolution topography
No full textRoad networks in mountainous forest landscapes have the potential to increase the susceptibility to erosion and shallow landsliding. The same issue is observed also for minor trail networks, with evidences of surface erosion due to surface flow redistribution. This could be a problem in regions such as the Italian Alps where forestry and tourist activities are a relevant part of the local economy. This is just one among the several effects of modern anthropogenic forcing: it is now well accepted by the scientific community that we are living in a new era where human activities may leave a significant signature on the Earth, by altering its morphology, and significantly affecting the related surface processes. In this work, we proposed a methodology for the automatic recognition of roads and trails induced flow direction changes. The algorithm is based on the calculation of the drainage area variation in the presence, or in the absence of anthropic features such as roads and trails on hillslopes. To simulate the absence of alteration, the surface was smoothed considering moving windows of varying size. In the analysis, we used a 1 and 0.5 m Airborne Laser Swath Mapping technology (ALSM), using LiDAR (Light Detection And Ranging), and 0.2 m Terrestrial Laser Scanner (TLS) derived Digital Terrain Models (DTMs). The aim of the work is to underline the effectiveness of the proposed method based on high resolution topography in the detailed recognition of surface flow direction alteration due to roads, but also trail networks. We propose an automatic method to map at a large scale such alterations, also in areas where it is difficult to recognize them without a trail network surveyed in the field. This methodology could be considered as a support for modeling (i.e., terrain stability and erosion models), and it can be used to interactively assist the design of new infrastructure to reduce their effects on surface instabilities. The reported methodology could also have a role in risk management and environmental planning for mountain areas where tourism and the related economic activities are critical, and where also trails deserve attention due to induced slope instabilities
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