Search results for "Microscope"
showing 10 items of 1412 documents
Spin-Polarized Scanning Tunnelling Microscopy of Ultrathin Films
2006
Using low temperature spin-polarized scanning tunneling microscopy we have studied the morphology and magnetic properties of ultrathin Fe(0.5 ML)Au(0.5 ML) nanowires prepared on a Mo(110) single crystal. The Fe nanostripes grown by step flow on a Mo(110) at 700 K were covered by Au at RT, and subsequently annealed at 700 K. Differences in the morphology of Au on Fe(110)/Mo(110) and clean Mo(110) surfaces are observed and discussed. After annealing, the Mo is covered by a homogeneous FeAu ML alloy with several iron enriched islands which reveal an out-of-plane magnetic contrast. Direct lateral exchange coupling has been observed for these islands.
A new route to grow oxide nanostructures based on metal displacement deposition. Lanthanides oxy/hydroxides growth
2012
Abstract A metal displacement reaction has been used in order to cause precipitation of oxide nanostructures within pores of anodic alumina membrane (AAM) templates. Here, we focus on the displacement deposition of LnO/OH (Ln = La, Ce, Sm, Er) nanostructures using Zn as sacrificial anode, employing a specific cell arrangement where a galvanic couple was formed between zinc anode and the Au thin layer covering template pore bottom. Progress of displacement deposition reaction into template channels was monitored measuring the open circuit potential as well as pH changes of the electrolyte. A progressive de-activation of the anode surface was observed for long deposition times, caused by depo…
Anodic oxide films on tungsten—II. The morphology and dissolution of the films
1980
Abstract Scanning electron microscopy was used to investigate the morphology of anodic oxide films on tungsten, obtained in various conditions of anodization. Studies were made of the growth of porous films, whose thickness increases with time and depends upon the current density. Temperature and electrolyte composition influence the film morphology. Gravimetric measurements of film dissolution at 70°C show that after a transient time, the rate of metal dissolution and that of film formation coincide. The porous films thicken because tungsten dissolves as WO 2 2+ and precipitates as WO 3 .H 2 O.
Enhanced light confinement in a triangular aperture: Experimental evidence and numerical calculations
2005
We have recently demonstrated that the electric near-field emerging from a triangular aperture at the tip of a metal-coated tetrahedron of glass exhibits a highly confined and intense spot when the light incident from within the glass body is polarized perpendicularly to one edge of the aperture [Naber et al., Phys. Rev. Lett. 89, 210801 (2002)]. Here we present additional experimental material and a theoretical confirmation of this near-field optical effect. Based on the model of a triangular aperture in a planar metal film, we studied the influence of aperture size and film material on the field distribution. Even though our theoretical model is rather simplified as compared to the experi…
High temperature reactivity of nickel aluminide diffusion coatings
2008
Abstract The high-temperature oxidation behaviour of nickel aluminides has been studied at 900 °C in air under atmospheric pressure. Yttria doped and undoped specimens of nickel were aluminised and then oxidised for 100 h under isothermal and cycling conditions. The results showed that when yttria is added by metal-organic chemical vapour deposition technique prior to the aluminisation process, it increased the oxidation rate of aluminised nickel, but improved the oxide scale adherence under cyclic conditions. The effects of yttria on the scale morphology, oxidation behaviour and scale spallation tendency are discussed based on the experimental results, using X-ray diffraction (XRD), scanni…
Adhesion and Friction Forces between Spherical Micrometer-Sized Particles
1999
An experimental setup, based on the principles of atomic force microscopy (AFM), was used to measure directly the adhesion and rolling-friction forces between individual silica microspheres of radii between 0.5 and 2.5 \ensuremath{\mu}m. It showed that the linear dependence of the pull-off force on the particle radius is still valid for micron-sized particles. Rolling-friction forces between silica microspheres were measured for the first time by combining AFM methods and optical microscopy: They are $\ensuremath{\sim}100$ times lower than the corresponding adhesion forces.
Ordering of fluorite-type phases in erbium-doped oxyfluoride glass ceramics
2018
In this study, novel transparent Er3+ doped glass ceramics were prepared from melt-quenched oxyfluoride glasses with general composition of Na2O-NaF-BaF2-YbF3-Al2O3-SiO2. The crystallization of fluorite (BaF2, BaF2-YbF3, NaF-BaF2-YbF3 and Na0.5-xYb0.5+xF2+2x) and distorted fluorite (rhombohedral Ba4Yb3F17 and tetragonal NaF-BaF2-YbF3) phases was analysed in glass ceramics with different BaF2 and YbF3 ratio. The phase composition and microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Intense red upconversion luminescence (UCL) was detected under near-infrared excitation resulting from three photon upconversion followed by cross-relaxation betw…
Dynamic In Vivo Biocompatibility of Angiogenic Peptide Amphiphile Nanofibers
2009
Biomaterials that promote angiogenesis have great potential in regenerative medicine for rapid revascularization of damaged tissue, survival of transplanted cells, and healing of chronic wounds. Supramolecular nanofibers formed by self-assembly of a heparin-binding peptide amphiphile and heparan sulfate-like glycosaminoglycans were evaluated here using a dorsal skinfold chamber model to dynamically monitor the interaction between the nanofiber gel and the microcirculation, representing a novel application of this model. We paired this model with a conventional subcutaneous implantation model for static histological assessment of the interactions between the gel and host tissue. In the stati…
Bio-imaging with the helium-ion microscope: A review
2021
Scanning helium-ion microscopy (HIM) is an imaging technique with sub-nanometre resolution and is a powerful tool to resolve some of the tiniest structures in biology. In many aspects, the HIM resembles a field-emission scanning electron microscope (FE-SEM), but the use of helium ions rather than electrons provides several advantages, including higher surface sensitivity, larger depth of field, and a straightforward charge-compensating electron flood gun, which enables imaging of non-conductive samples, rendering HIM a promising high-resolution imaging technique for biological samples. Starting with studies focused on medical research, the last decade has seen some particularly spectacular …
Inulin coated plasmonic gold nanoparticles as a tumor-selective tool for cancer therapy.
2015
Preferential uptake by cancer cells of PEG-inulin coated gold nanoparticles loaded with the drug doxorubicin.