Search results for "TRANSMISSION ELECTRON"
showing 10 items of 426 documents
Tailoring of highly porous SnO2 and SnO2-Pd thin films
2019
Abstract Tin oxide is a material that attracts attention due to variety of technological applications. The main parameters that influence its properties are morphology, crystalline structure and stoichiometry. Researchers try to develop nanostructured thin films with tunable parameters that would conform its technological applications. Herein, we report on the preparation and characterization of highly porous SnO2 and Pd-doped SnO2 thin films. These films were deposited in the form of nanorods with controllable geometry. Such morphology was achieved by utilizing glancing angle deposition (GLAD) with assisted magnetron sputtering. This arrangement allowed preparation of slanted pillars, zig-…
Combination of Confocal Raman Spectroscopy and Electron Microscopy on the Same Individual Bundles of Single-Walled Carbon Nanotubes
2002
We report a method to investigate the same individual single-walled carbon nanotube (SWNT) bundles with both transmission electron microscopy (TEM) and Raman spectroscopy. Free-standing individual bundles are obtained by depositing a solution of suspend SWNTs on a carbon film with a regular pattern of holes, which can be localized by TEM and also by confocal Raman microscopy. While most of the TEM images predict that the bundles consist of tubes with a similar diameter, we will show that occasionally a certain tube diameter can be associated with a particular radial breathing mode frequency of the Raman spectrum. Single-walled carbon nanotubes (SWNTs) are one-dimensional molecular structure…
Insights into the formation of metal carbon nanocomposites for energy storage using hybrid NiFe layered double hydroxides as precursors
2020
[EN] NiFe-carbon magnetic nanocomposites prepared using hybrid sebacate intercalated layered double hydroxides (LDHs) as precursors are shown to be of interest as supercapacitors. Here, the low-temperature formation mechanism of these materials has been deciphered by means of a combined study using complementaryin situ(temperature-dependent) techniques. Specifically, studies involving X-ray powder diffraction, thermogravimetry coupled to mass spectrometry (TG-MS), statistical Raman spectroscopy (SRS), aberration-corrected scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) have been carried out. The experimental results confirm the early formation o…
Variation of lattice constant and cluster formation in GaAsBi
2013
We investigate the structural properties of GaAsBi layers grown by molecular beam epitaxy on GaAs at substrate temperatures between 220–315 C. Irrespective of the growth temperature, the structures exhibited similar Bi compositions, and good overall crystal quality as deduced from X-Ray diffraction measurements. After thermal annealing at temperatures as low as 500 C, the GaAsBi layers grown at the lowest temperatures exhibited a significant reduction of the lattice constant. The lattice variation was significantly larger for Bi-containing samples than for Bi-free low-temperature GaAs samples grown as a reference. Rutherford backscattering spectrometry gave no evidence of Bi diffusing out o…
A comparison of the Raman LAM and electron microscopy in determining crystallite thickness distributions: Polyethylenes with narrow size distributions
1989
Bon accord entre les resultats obtenus pour des polyethylenes cristallises a 118 o C pendant 2 et 20 minutes lorsqu'on prend en compte l'inclinaison de la chaine et pour des polymeres a distribution etroite
Axonemal Symmetry Break, a New Ultrastructural Diagnostic Tool for Primary Ciliary Dyskinesia?
2022
Diagnosis testing for primary ciliary dyskinesia (PCD) requires a combination of investigations that includes study of ciliary beat pattern by high-speed video-microscopy, genetic testing and assessment of the ciliary ultrastructure by transmission electron microscopy (TEM). Historically, TEM was considered to be the “gold standard” for the diagnosis of PCD. However, with the advances in molecular genetic techniques, an increasing number of PCD variants show normal ultrastructure and cannot be diagnosed by TEM. During ultrastructural assessment of ciliary biopsies of patients with suspicion of PCD, we observed an axonemal defect not previously described that affects peripheral doublets tilt…
Ultrastructure of Spinal Dura Mater
2014
Pia mater is the innermost of the three meningeal membranes, closely surrounding the brain, the spinal cord, and the portion of spinal nerve roots extending towards their exit across the dura mater. A cellular layer and a subpial compartment shape the structure of the pia mater. The cellular layer is made up of flat, overlapping pial cells with amorphous, fundamental substance interposed among them. The surface of the cellular plane appears smooth and bright under scanning electron microscopy (SEM). Transmission electron microscopy shows that the cellular component is about three to five pial cells thick at the medullary level and two to three cells thick at the level of the nerve roots. Th…
Small-Angle Scattering from Phase-Separated Metallic Alloys: From Experiment to Phase Diagrams
1994
In this paper, phase-separated metallic alloys are described in terms of concentration fluctuations. As a consequence, Small Angle Scattering equations which allow to calculate the entire scattering curve by incorporating particle-particle interference effects on the basis of the Percus-Yevick formalism, are obtained. It is shown that, for Aluminium-Lithium alloys, satisfactory fits of the experimental data can be obtained if it is assumed that Li rich elliptical monodisperse precipitate particles approach each other at average distances which are larger than the sum of the hard-sphere particle radii. It is also shown that a possible ambiguity of this model, within the Percus-Yevick formali…
Oil-Water Interface Templating of Mesoporous Macroscale Structures
1996
Ordered mesostructured porous silicas that are also macroscopically structured were created by control of the interface on two different length scales simultaneously. Micellar arrays controlled the nanometer-scale assembly, and at the static boundary between an aqueous phase and an organic phase, control was achieved on the micrometer to centimeter scale. Acid-prepared mesostructures of silica were made with the p6, Pm3n, and the P63/mmc structures in the form of porous fibers 50 to 1000 micrometers in length, hollow spheres with diameters of 1 to 100 micrometers, and thin sheets up to 10 centimeters in diameter and about 10 to 500 micrometers in thickness. These results might have implicat…
Characterization of the nanocomposite laminate structure occurring in fish scales from Arapaima Gigas
2008
In the present paper, the nanocomposite laminate structure of scales from the Amazonian fish Arapaima Gigas is investigated. The structure and composition of the scales were assessed by means of X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR). The theory of Fickian diffusion is used and discussed in order to rationalize the water absorption and desorption behavior of the scales. Morphology studies and fracture analysis of the native scales were carried out using Transmission Electron Microscopy (TEM), Light Optical Microscopy (LOM) and Scanning Electron Microscopy (SEM). A fibrous layer of collagen and a plywood-like structure were observed. In order to study the …