Search results for "Microscopy"
showing 10 items of 3390 documents
Scanning probe microscopy of pine and birch kraft pulp fibres
2000
Abstract Fibres of the conventional pine and birch kraft pulps were characterized by scanning probe microscopy (SPM). The surface characteristics of these pulps taken at the early stages of pulping were compared with those from later stages of pulping (with or without subsequent oxygen/alkali delignification). It was observed that during delignification a granular surface structure was replaced by a fibrillar surface containing various disruptions. The granular and fibrillar regions were particularly well resolved by using phase imaging in tapping mode of SPM. It was concluded that the granular structure corresponded to surface lignin since the decrease in the relative amount of the granula…
Imaging Topological Spin Structures Using Light-Polarization and Magnetic Microscopy
2020
We present an imaging modality that enables detection of magnetic moments and their resulting stray magnetic fields. We use wide-field magnetic imaging that employs a diamond-based magnetometer and has combined magneto-optic detection (e.g. magneto-optic Kerr effect) capabilities. We employ such an instrument to image magnetic (stripe) domains in multilayered ferromagnetic structures.
Sulfidation Mechanism of Pure and Cu-Doped ZnO Nanoparticles at Moderate Temperature: TEM and In Situ XRD Studies
2012
International audience; Sulfidation mechanism of pure and Cu-doped ZnO nanoparticles (Cu0.03Zn0.97O and Cu0.06Zn0.94O) at 250 and 350 degrees C was studied by transmission electron microscopy (TEM) and in situ synchrotron XRD. For nondoped ZnO, we observed by TEM that partial reaction with H2S is accompanied by the formation of voids at the ZnO/ZnS interface. This phenomenon (known as the Kirkendall effect) confirms that sulfidation of nanosized ZnO by gaseous H2S proceeds via the outward growth of ZnS: Zn2+ and O2- are transferred to the external (ZnS/gas) surface, where zinc is combined with sulfur and oxygen reacts with protons yielding H2O. During sulfidation of Cu-doped ZnO, the caviti…
Structural and optical properties of novel surfactant-coated Yb-TiO2 nanoparticle
2010
Abstract In this paper a novel hybrid approach to synthesise composite nanoparticles is presented. It is based on the laser ablation of a bulk target (Yb) immersed in a reversed micellar solution which contains nanoparticles of a different host material (TiO2 nanoparticles) previously synthesised by chemical method. This approach thus exploits the advantages of the chemical synthesis through reversed micellar solution (size control, nanoparticle stabilisation), and of the laser ablation (‘‘clean’’ synthesis, no side reactions). Central role is played by the microscopic processes controlling the deposition of the ablated Yb atoms onto the surface of TiO2 nanoparticles which actually behave a…
Gallium nitride thin films as processed by several techniques: Their possible applications for PV-devices
2011
We present in this work the characterization studies carried on GaN — thin films as processed by the Close Spaced Vapor Technique (CSVT), Laser Ablation (LA), and Molecular Beam Epitaxy (MBE), under particular growth parameters for each of the three techniques. The films characterization was performed by x-ray diffraction (X-RD), Photoluminescence (PL), Raman spectroscopy, optical transmission, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). With these results an analysis of the samples was done, with an aim for a possible application of these thin films for PV-devices.
Alkoxide-intercalated CoFe-layered double hydroxides as precursors of colloidal nanosheet suspensions: structural, magnetic and electrochemical prope…
2014
Alkoxide-intercalated CoFe-layered double hydroxides (CoFe–LDHs) were synthesized via the non-aqueous methanolic route. According to powder X-ray diffraction and field emission scanning electron microscopy, they exhibit a nanosized plate-like morphology with a basal space of 9.21 A. The hydrolysis of the material in water leads to colloidal suspensions of nanosheets with lateral dimensions of about 20 nm and thicknesses of ca. 4 nm as demonstrated by atomic force microscopy and dynamic light scattering. Atomic resolution scanning transmission electron microscopy combined with electron energy-loss spectroscopy confirm the high crystalline quality of the crystals and the proper Co/Fe stoichio…
Near-field scanning optical microscopy to study nanometric structural details of LiNbO3 Zn-diffused channel waveguides
2008
A near-field scanning optical microscope (NSOM) is used to perform structural and optical characterization of the surface layer after Zn diffusion in a channel waveguide fabricated on lithium niobate. A theoretical approach has been developed in order to extract refractive index contrast from NSOM optical transmission measurements (illumination configuration). As a result, different solid phases present on the sample surface can be identified, such as ZnO and ZnNb2O6. They appear like submicrometric crystallites aligned along the domain wall direction, whose origin can be ascribed to some strain relaxation mechanism during the annealing process after Zn diffusion. Jose.Canet-Ferrer@uv.es
Atomic force microscopy visualization of injuries in Enterococcus faecalis surface caused by Er,Cr:YSGG and diode lasers
2014
Aim: To visualize by Atomic Force Microscopy the alterations induced on Enterococcus. faecalis surface after treatment with 2 types of laser: Erbium chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and Diode laser. Material and Methods: Bacterial suspensions from overnight cultures of E. faecalis were irradiated during 30 seconds with the laser-lights at 1 W and 2 W of power, leaving one untreated sample as control. Surface alterations on treated E. faecalis were visualized by Atomic Force Microscopy (AFM) and its surface roughness determined. Results: AFM imaging showed that at high potency of laser both cell morphology and surface roughness resulted altered, and that several ce…
Structural analysis of W3O/WO3 and TiO/TiO2 periodic multilayer thin films sputter deposited by the reactive gas pulsing process
2012
International audience; DC reactive sputtering was used to deposit titanium and tungsten-based metal/oxide periodic nanometric multilayers using pure metallic targets and Ar + O-2 gas mixture as reactive atmosphere. The innovative technique namely, the reactive gas pulsing process allows switching between the metal and oxide to prepare a periodic multilayered structure with various metalloid concentrations and nanometric dimensions. The same pulsing period was used for each deposition to produce metal-oxide periodic alternations close to 10 nm. Structure, crystallinity and chemical composition of these films were systematically investigated by Raman spectroscopy, X-ray diffraction and Energ…
Chemical hydrogels based on a hyaluronic acid-graft-α-elastin derivative as potential scaffolds for tissue engineering
2013
In this work hyaluronic acid (HA) functionalized with ethylenediamine (EDA) has been employed to graft α-elastin. In particular a HA-EDA derivative bearing 50 mol% of pendant amino groups has been successfully employed to produce the copolymer HA-EDA-g-α-elastin containing 32% w/w of protein. After grafting with α-elastin, remaining free amino groups reacted with ethylene glycol diglycidyl ether (EGDGE) for producing chemical hydrogels, proposed as scaffolds for tissue engineering. Swelling degree, resistance to chemical and enzymatic hydrolysis, as well as preliminary biological properties of HA-EDA-g-α-elastin/EGDGE scaffold have been evaluated and compared with a HA-EDA/EGDGE scaffold. T…