Search results for "Scanning"
showing 10 items of 1808 documents
Local tunneling study of three-dimensional order parameter in the pi band of Al-doped MgB2 single crystals
2007
We have performed local tunneling spectroscopy on high quality Mg$_{1-x}$Al$_x$B$_2$ single crystals by means of Variable Temperature Scanning Tunneling Spectroscopy (STS) in magnetic field up to 3 Tesla. Single gap conductance spectra due to c-axis tunneling were extensively measured, probing different amplitudes of the three-dimensional $\Delta_\pi$ as a function of Al content. Temperature and magnetic field dependences of the conductance spectra were studied in S-I-N configuration: the effect of the doping resulted in a monotonous reduction of the locally measured $T_C$ down to 24K for x=0.2. On the other hand, we have found that the gap amplitude shows a maximum value $\Delta_\pi= 2.3$ …
Photo-polymerized lauryl methacrylate monolithic columns for CEC using lauroyl peroxide as initiator
2009
Lauryl methacrylate (LMA)-ester based monolithic columns photo-polymerized using lauroyl peroxide (LPO) as initiator were prepared, and their morphological and CEC properties were studied. The composition of the polymerization mixture (i.e. ratios of monomers/porogenic solvents, 1,4-butanediol/1-propanol and LMA/crosslinker) was optimized. The morphological and chromatographic properties of LMA columns were evaluated by means of SEM pictures and van Deemter plots of PAHs, respectively. The polymerization mixture selected as optimal provided a fast separation of a mixture of PAHs with excellent efficiencies (minimum plate heights of 8.9-11.1 μm). Satisfactory column-to-column (RS D < 4.5%) a…
Comparison on photo-initiators for the preparation of methacrylate monolithic columns for capillary electrochromatography.
2010
The synthesis of lauryl methacrylate monoliths for capillary electrochromatography by UV polymerization using several free-radical initiators (alpha,alpha'-azobisisobutyronitrile, 2,2-dimethoxy-2-phenylacetophenone, dibenzoyl peroxide (BPO) and lauroyl peroxide (LPO)) has been investigated. Using a 1,4-butanediol/1-propanol mixture as porogenic solvent, the influence of each initiator and its content on the morphological and electrochromatographical properties of beds was evaluated. Under their respective optimum content, satisfactory separations of a test mixture of PAHs with similar efficiencies (minimum plate heights of 8.0-12.7 microm obtained from Van Deemter plots) were achieved for t…
CEC column behaviour of butyl and lauryl methacrylate monoliths prepared in non-aqueous media
2009
Polymeric monolithic stationary phases for capillary electrochromatography were prepared using two bulk monomers, butyl methacrylate (BMA) and lauryl methacrylate (LMA), by in situ polymerization in non-aqueous media. The effect of 1,4-butanediol/1-propanol ratio on porous properties was investigated separately for each monomer, keeping the proportion of monomers to pore-forming solvents fixed at 40:60 wt:wt. Also, mixtures of BMA and LMA at different 1,4-butanediol/1-propanol ratios were studied for tailoring the morphological features of the monolithic columns. The chromatographic performance of the different columns was evaluated by means of van Deemter plots of polycyclic aromatic hydro…
Full-Waveform Terrestrial Laser Scanning for Extracting a High-Resolution 3D Topographic Model: a Case Study on an Area of Archaeological Significance
2014
AbstractThis paper describes a method, which uses full-waveform terrestrial laser scanning to survey the surface of the slope below the Temple of Juno, located in the Valley of the Temples in Agrigento (Sicily, Southern Italy). The surface is characterized by the presence of large rock blocks, which have fallen down from the upper side; possible further detachments of rock blocks would cause a situation of general instability, with a very high risk to the archaeological structures in the near future. The methodology was designed to evaluate the potential of full-waveform laser scanning technology for the production of a very high resolution 3D topographic model of the slope, to be used as a…
Hierarchical imaging and computational analysis of three-dimensional vascular network architecture in the entire postnatal and adult mouse brain
2021
The formation of new blood vessels and the establishment of vascular networks are crucial during brain development, in the adult healthy brain, as well as in various diseases of the central nervous system. Here, we describe a step-by-step protocol for our recently developed method that enables hierarchical imaging and computational analysis of vascular networks in postnatal and adult mouse brains. The different stages of the procedure include resin-based vascular corrosion casting, scanning electron microscopy, synchrotron radiation and desktop microcomputed tomography imaging, and computational network analysis. Combining these methods enables detailed visualization and quantification of t…
Comparative Study of Different Methods for the Prediction of Drug–Polymer Solubility
2015
In this study, a comparison of different methods to predict drug-polymer solubility was carried out on binary systems consisting of five model drugs (paracetamol, chloramphenicol, celecoxib, indomethacin, and felodipine) and polyvinylpyrrolidone/vinyl acetate copolymers (PVP/VA) of different monomer weight ratios. The drug-polymer solubility at 25 °C was predicted using the Flory-Huggins model, from data obtained at elevated temperature using thermal analysis methods based on the recrystallization of a supersaturated amorphous solid dispersion and two variations of the melting point depression method. These predictions were compared with the solubility in the low molecular weight liquid ana…
Castellaccio of Monreale: From the Survey to the Visualisation of Virtual Reconstructions
2023
On Monte Caputo near Monreale stands a castle, presumably built in the twelfth century. The paper presents the first results of a still in progress survey activity, carried out on the entire monument using laser scanning and photogram-metric methods. This activity was carried out as part of a scientific agreement stipu-lated between the University of Palermo, Department of Architecture and the Club Alpino Siciliano, owner of the Castle. The graphic restitution of the survey provided new information and unpublished images of the castle. It was then possible to formu-late hypotheses on the virtual reconstruction of lost configurations. This was achiev-able thanks to the survey analytical read…
Does the brain know who is at the origin of what in an imitative interaction?
2012
International audience; Brain correlates of the sense of agency have recently received increased attention. However, the explorations remain largely restricted to the study of brains in isolation. The prototypical paradigm used so far consists of manipulating visual perception of own action while asking the subject to draw a distinction between self- versus externally caused action. However, the recent definition of agency as a multifactorial phenomenon combining bottom-up and top-down processes suggests the exploration of more complex situations. Notably there is a need of accounting for the dynamics of agency in a two-body context where we often experience the double faceted question of w…
Porous structure of fibre networks formed by a foaming process: a comparative study of different characterization techniques
2016
Recent developments in making fibre materials using the foam-forming technology have raised a need to characterize the porous structure at low material density. In order to find an effective choice among all structure-characterization methods, both two-dimensional and three-dimensional techniques were used to explore the porous structure of foam-formed samples made with two different types of cellulose fibre. These techniques included X-ray microtomography, scanning electron microscopy, light microscopy, direct surface imaging using a CCD camera and mercury intrusion porosimetry. The mean pore radius for a varying type of fibre and for varying foam properties was described similarly by all …