Search results for "Scanning"
showing 10 items of 1808 documents
Spatio-temporal Characteristics of THz Emission at the Subwavelength Scale via Optical Rectification
2011
Highly localized THz emission via optical rectification in thin nonlinear crystals is a promising method for subwavelength microscopy. We present here the peculiar THz spatio-temporal characteristics induced by the non-paraxial generation regime.
Properties of silicon integrated photonic lenses: bandwidth, chromatic aberration, and polarization dependence
2013
We analyze the properties of silicon integrated photonic lenses based on scattering optical elements. The devices have been inverse- designed by combining genetic algorithms and the multiple scattering theory. These lenses are able to focus an infrared plane wave front on a position freely determined during the design stage. The nanofabricated silicon integrated lenses have proved effective over a large range of wave- lengths, measured to be of the order of 100 nm. The lenses show chromatic aberration, with a displacement of the position of the focus mea- sured to be higher than 1.5 μm when the wavelength varies from 1500 to 1600 nm. Moreover, we analyze the polarization of the focused beam…
Optical field molding within near-field coupled twinned nanobeam cavities
2011
Twinned high Q nanobeam cavities can be optically coupled while being placed in the optical near-field of each other. They form then a new optical system which supports discrete field maps addressable by wavelength selection.
In-Depth Investigation of the Safety of Wooden Shelves Used for Traditional Cheese Ripening
2021
ABSTRACT The main goal of this research was to characterize the bacterial diversity of the wooden boards used for aging traditional Sicilian cheeses and to evaluate whether pathogenic bacteria are associated with these surfaces. Eighteen cheese dairy factories producing three traditional cheese typologies (PDO Pecorino Siciliano, PDO Piacentinu Ennese, and Caciocavallo Palermitano) were selected within the region of Sicily. The wooden shelf surfaces were sampled by a destructive method to detach wood splinters as well as by a nondestructive brushing to collect microbial cells. Scanning electron microscopy showed the presence of almost continuous bacterial formations on the majority of the s…
The impact of whey protein preheating on the properties of emulsion gel bead
2014
Thermal treatment effect (70 or 80 °C for 5 or 30 min) was evaluated on functional properties of whey protein isolate (WPI) dispersions used for the development of novel vitamin A delivery systems based on emulsion gel beads. This process combines an (O/W) emulsion diluted by a polysaccharide solution and a cold-set gelation induced by salt addition. Pre-heated WPI had a significant impact on the denaturation degree and on the surface hydrophobicity, respectively studied by differential scanning calorimetry and fluorescence. Stronger heating conditions (i.e. duration or temperature) induced complete denaturation, an increase of surface hydrophobicity and of viscosity. Under these conditions…
Liquid and vapour water transfer through whey protein/lipid emulsion films
2010
BACKGROUND: Edible films and coatings based on protein/lipid combinations are among the new products being developed in order to reduce the use of plastic packaging polymers for food applications. This study was conducted to determine the effect of rapeseed oil on selected physicochemical properties of cast whey protein films. RESULTS: Films were cast from heated (80 °C for 30 min) aqueous solutions of whey protein isolate (WPI, 100 g kg−1 of water) containing glycerol (50 g kg−1 of WPI) as a plasticiser and different levels of added rapeseed oil (0, 1, 2, 3 and 4% w/w of WPI). Measurements of film microstructure, laser light-scattering granulometry, differential scanning calorimetry, wetti…
Manipulation of nanoparticles of different shapes inside a scanning electron microscope
2014
In this work polyhedron-like gold and sphere-like silver nanoparticles (NPs) were manipulated on an oxidized Si substrate to study the dependence of the static friction and the contact area on the particle geometry. Measurements were performed inside a scanning electron microscope (SEM) that was equipped with a high-precision XYZ-nanomanipulator. To register the occurring forces a quartz tuning fork (QTF) with a glued sharp probe was used. Contact areas and static friction forces were calculated by using different models and compared with the experimentally measured force. The effect of NP morphology on the nanoscale friction is discussed.
Complex tribomechanical characterization of ZnO nanowires: nanomanipulations supported by FEM simulations
2016
In the present work, we demonstrate a novel approach to nanotribological measurements based on the bending manipulation of hexagonal ZnO nanowires (NWs) in an adjustable half-suspended configuration inside a scanning electron microscope. A pick-and-place manipulation technique was used to control the length of the adhered part of each suspended NW. Static and kinetic friction were found by a 'self-sensing' approach based on the strain profile of the elastically bent NW during manipulation and its Young's modulus, which was separately measured in a three-point bending test with an atomic force microscope. The calculation of static friction from the most bent state was completely reconsidered…
Direct Writing on Copper Ion Doped Silica Films by Electrogeneration of Metallic Microstructures
2017
International audience; A facile and rapid localized electrochemical reduction of colloid copper particles is proposed using the scanning electrochemical,microscope (SECM), technique. In this purpose, thin films of composite silica :glass containing copper salts were prepared by the sol-gel method via the dip coating technique. Acid-catalyzed tetraethylorthosilane (TEOS) solutions charged with copper nitrate were used as precursors. This one-pot experiment can be performed in mild conditions. The localized generation of copper metallic nanostructures on silica film has been performed by electroreduction of methyl viologen on an ultramicroelectrode (UME). The UME generates reducing species, …
Electronic and magnetic properties of Mn 12 molecular magnets on sulfonate and carboxylic acid prefunctionalized gold surfaces
2012
Structural, electronic, and magnetic properties of [Mn 12O 12(bet) 16(EtOH) 4](PF 6) 14·4CH 3CN·H 2O (in short Mn 12bet, bet = betaine = +N(CH 3) 3-CH 2-COO -) single-molecule magnets (SMMs) deposited on previously functionalized gold surfaces have been investigated. Self-assembled monolayers (SAMs) either of sodium mercaptoethanesulfonate (MES) or mercaptopropionic acid (MPA) are used as functionalization to avoid the direct interaction between the Mn 12bet molecules and the Au surface with the aim of preserving the main functional properties of the molecules. Scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) analysis show deposited Mn 12bet SMMs well-isolated …