Search results for "RFA"
showing 10 items of 11106 documents
Survey and Photogrammetric Restitution of Monumental Complexes: Issues and Solutions—The Case of the Manfredonic Castle of Mussomeli
2019
The latest results obtained through photogrammetric restitution enhanced by GNSS (Global Navigation Satellite System) RTK (Real-Time Kinematic) survey achieved increased levels of accuracy. These survey solutions are used to rapidly obtain a detailed model with an excellent level of accuracy (centimetric) with cheaper equipment. However, the contour conditions are not always favorable for obtaining the best results in a simple way. The work presented in this paper shows the survey and the photogrammetric restitution of the Manfredonic Castle of Mussomeli in Sicily, developed as a part of the PON NEPTIS European Project, aimed at the valorization of Cultural Heritage (CH). This case is a typ…
Two-dimensional and three-dimensional sonography of conjoined twins.
2002
Purpose The aim of this study was to evaluate and compare the diagnostic capabilities of 2-dimensional (2D) and 3-dimensional (3D) sonography for the study of conjoined twins. Methods Four pregnant women with an initial 2D sonographic diagnosis of conjoined twins were examined with color Doppler sonography, 3D multiplanar sonography, and orthogonal plane imaging and 3D surface rendering. Results All 4 cases of conjoined twins were initially diagnosed with either transvaginal or transabdominal 2D sonography. 3D sonography afforded more realistic views and demonstrated more clearly the linking areas and surface anomalies, but 2D and color Doppler sonography provided more definitive and specif…
Preparation of polycrystalline TiO2 photocatalysts impregnated with various transition metal ions : characterization and photocatalytic activity for …
2002
A set of polycrystalline TiO2 photocatalysts loaded with various ions of transition metals (Co, Cr, Cu, Fe, Mo, V, and W) were prepared by using the wet impregnation method. The samples were characterized by using some bulk and surface techniques, namely X-ray diffraction, BET specific surface area determination, scanning electron microscopy, point of zero charge determination, and femtosecond pump-probe diffuse reflectance spectroscopy (PP-DRS). The samples were employed as catalysts for 4-nitrophenol photodegradation in aqueous suspension, used as a probe reaction. The characterization results have confirmed the difficulty to find a straightforward correlation between photoactivity and si…
Characterization of the Solid State Properties of Anodic Oxides on Magnetron Sputtered Ta, Nb and Ta-Nb Alloys
2012
Tantalum oxide, niobium oxide and Ta-Nb containing mixed oxides were grown by anodizing sputter-deposited Ta, Nb and Ta-Nb alloys of different compositions. A photoelectrochemical investigation was performed in order to estimate the band gap and the flat band potential of the oxides as a function of their composition. The band gap of the investigated Ta-Nb containing mixed oxides changed monotonically between those estimated for Ta2O5 (4.1 eV) and Nb2O5 (3.4 eV) and in agreement with a proposed correlation between the Band gap of an oxide and the difference of electronegativity of the oxide constituents. From the differential capacitance curves recorded in a wide range of electrode potentia…
Minimality via second variation for microphase separation of diblock copolymer melts
2017
Abstract We consider a non-local isoperimetric problem arising as the sharp interface limit of the Ohta–Kawasaki free energy introduced to model microphase separation of diblock copolymers. We perform a second order variational analysis that allows us to provide a quantitative second order minimality condition. We show that critical configurations with positive second variation are indeed strict local minimizers of the problem. Moreover, we provide, via a suitable quantitative inequality of isoperimetric type, an estimate of the deviation from minimality for configurations close to the minimum in the L 1 {L^{1}} -topology.
Effect of high temperature annealing (T > 1650 °C) on the morphological and electrical properties of p-type implanted 4H-SiC layers
2019
This work reports on the effect of high temperature annealing on the electrical properties of p-type implanted 4H-SiC. Ion implantations of Aluminum (Al) at different energies (30-200 keV) were carried out to achieve 300 nm thick acceptor box profiles with a concentration of about 10(20) at/cm(3). The implanted samples were annealed at high temperatures (1675-1825 degrees C). Morphological analyses of the annealed samples revealed only a slight increase of the surface roughness RMS up to 1775 degrees C, while this increase becomes more significant at 1825 degrees C (RMS = 1.2 nm). Room temperature Hall measurements resulted in a hole concentration in the range 0.65-1.34 x 10(18)/cm(3) and m…
Tunable Superstructures of Dendronized Graphene Nanoribbons in Liquid Phase
2019
In this Communication, we report the first synthesis of structurally well-defined graphene nanoribbons (GNRs) functionalized with dendritic polymers. The resultant GNRs possess grafting ratios of 0.59-0.68 for the dendrons of different generations. Remarkably, the precise 3D branched conformation of the grafted dendrons affords the GNRs unprecedented 1D supramolecular self-assembly behavior in tetrahydrofuran (THF), yielding nanowires, helices and nanofibers depending on the dimension of the dendrons. The GNR superstructures in THF exhibit near-infrared absorption with maxima between 650 and 700 nm, yielding an optical bandgap of 1.2-1.3 eV. Ultrafast photoconductivity analyses unveil that …
Surface charges at the CaF2/water interface allow very fast intermolecular vibrational-energy transfer
2020
Abstract We investigate the dynamics of water in contact with solid calcium fluoride, where at low pH, localized charges can develop upon fluorite dissolution. We use 2D surface‐specific vibrational spectroscopy to quantify the heterogeneity of the interfacial water (D2O) molecules and provide information about the sub‐picosecond vibrational‐energy‐relaxation dynamics at the buried solid/liquid interface. We find that strongly H‐bonded OD groups, with a vibrational frequency below 2500 cm−1, display very rapid spectral diffusion and vibrational relaxation; for weakly H‐bonded OD groups, above 2500 cm−1, the dynamics slows down substantially. Atomistic simulations based on electronic‐structu…
Rational Design of Thermoresponsive Microgel Templates with Polydopamine Surface Coating for Microtissue Applications.
2021
Functional microgels provide a versatile basis for synthetic in vitro platforms as alternatives to animal experiments. The tuning of the physical, chemical, and biological properties of synthetic microgels can be achieved by blending suitable polymers and formulating them such to reflect the heterogenous and complex nature of biological tissues. Based on this premise, this paper introduces the development of volume-switchable core-shell microgels as 3D templates to enable cell growth for microtissue applications, using a systematic approach to tune the microgel properties based on a deep conceptual and practical understanding. Microscopic microgel design, such as the tailoring of the microg…
Existence de points fixes enlacés à une orbite périodique d'un homéomorphisme du plan
1992
Let f be an orientation-preserving homeomorphism of the plane such that f-Id is contracting. Under these hypotheses, we establish the existence, for every periodic orbit, of a fixed point which has nonzero linking number with this periodic orbit.