Template-Assisted Fabrication of Double-Shelled Nanotubes Composed of Inner Shell Pb(Zr0.52Ti0.48)O3 and Outer Shell TiO2 by Sol-Gel Process with Spin-Coating Technique

2011 ◽  
Vol 1292 ◽  
Author(s):  
Y. C. Choi ◽  
S. Y. Cho ◽  
S. D. Bu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spin Coating ◽  
Sol Gel ◽  
Outer Shell ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Scanning Transmission ◽  
Diffraction Patterns

ABSTRACTDouble-shelled nanotubes composed of inner shell Pb(Zr0.52Ti0.48)O3 (PZT) and outer shell TiO2 are successfully fabricated by a spin coating of each sol-gel solution on porous anodic alumina template. Field emission transmission electron microscopy images show that they have a ~ 10 nm wall thickness. The selected area electron diffraction patterns show that they have two mixed crystalline phases of tetragonal PZT and anatase TiO2. The analyses of scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy confirm their uniform distribution of each element.

scholarly journals Fabrication of TiO2Nanotanks Embedded in a Nanoporous Alumina Template

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
C. Massard ◽  
S. Pairis ◽  
V. Raspal ◽  
Y. Sibaud ◽  
K. O. Awitor
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Alumina Template ◽  
Nanoporous Alumina ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Sol Gel Process

The feasibility of surface nanopatterning with TiO2nanotanks embedded in a nanoporous alumina template was investigated. Self-assembled anodized aluminium oxide (AAO) template, in conjunction with sol gel process, was used to fabricate this nanocomposite object. Through hydrolysis and condensation of the titanium alkoxide, an inorganic TiO2gel was moulded within the nanopore cavities of the alumina template. The nanocomposite object underwent two thermal treatments to stabilize and crystallize the TiO2. The morphology of the nanocomposite object was characterized by Field Emission Scanning Electron Microscopy (FESEM). The TiO2nanotanks obtained have cylindrical shapes and are approximately 69 nm in diameter with a tank-to-tank distance of 26 nm. X-ray diffraction analyses performed by Transmission Electron Microscopy (TEM) with selected area electron diffraction (SAED) were used to investigate the TiO2structure. The optical properties were studied using UV-Vis spectroscopy.

A Transmission Electron Microscopy Study of CoFe2O4 Ferrite Nanoparticles in Silica Aerogel Matrix Using HREM and STEM Imaging and EDX Spectroscopy and EELS

2010 ◽  
Vol 16 (2) ◽  
pp. 200-209 ◽  
Author(s):  
Andrea Falqui ◽  
Anna Corrias ◽  
Peng Wang ◽  
Etienne Snoeck ◽  
Gavin Mountjoy
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Interlayer Spacing ◽  
Microscopy Study ◽  
Nanocomposite Materials ◽  
Electron Microscopy Study ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractMagnetic nanocomposite materials consisting of 5 and 10 wt% CoFe2O4 nanoparticles in a silica aerogel matrix have been synthesized by the sol-gel method. For the CoFe2O4-10wt% sample, bright-field scanning transmission electron microscopy (BF STEM) and high-resolution transmission electron microscopy (HREM) images showed distinct, rounded CoFe2O4 nanoparticles, with typical diameters of roughly 8 nm. For the CoFe2O4-5wt% sample, BF STEM images and energy dispersive X-ray (EDX) measurements showed CoFe2O4 nanoparticles with diameters of roughly 3 ± 1 nm. EDX measurements indicate that all nanoparticles consist of stoichiometric CoFe2O4, and electron energy-loss spectroscopy measurements from lines crossing nanoparticles in the CoFe2O4-10wt% sample show a uniform composition within nanoparticles, with a precision of at best than ±0.5 nm in analysis position. BF STEM images obtained for the CoFe2O4-10wt% sample showed many “needle-like” nanostructures that typically have a length of ∼10 nm and a width of ∼1 nm, and frequently appear to be attached to nanoparticles. These needle-like nanostructures are observed to contain layers with interlayer spacing 0.33 ± 0.1 nm, which could be consistent with Co silicate hydroxide, a known precursor phase in these nanocomposite materials.

TEM Study of Rutile-Phase TiO2 Nanosheets

2013 ◽  
Vol 850-851 ◽  
pp. 156-159
Author(s):  
Xin Yan Wu ◽  
Wei Xiong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Activity ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
Rutile Phase ◽  
High Photocatalytic Activity ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process

TiO2 nanosheets have been successfully synthesized via a simple sol-gel process. These nanostructures were characterized by transmission electron microscopy (TEM) and x-ray energy dispersive spectrometer (EDS). The sheet-shaped single-crystalline nanostructures are pure rutile-phase structure, with landscape dimension of 10-45 nm. EDS investigation confirms that the TiO2 nanosheets are only composed of Ti and O, and the atomic ration of Ti and O is close to 1:2. High photocatalytic activity might be expected for those TiO2 nanosheets due to their large surface area.

Microstructural Studies of Pulsed-Laser Irradiated Graphite Surfaces

1985 ◽  
Vol 51 ◽  
Author(s):  
J. S. Speck ◽  
J. Steinbeck ◽  
G. Braunstein ◽  
M. S. Dresselhaus ◽  
T. Venkatesan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Outer Boundary ◽  
Pyrolytic Graphite ◽  
Areal Density ◽  
Uniform Density ◽  
Fine Grain ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Diffraction Patterns

ABSTRACTThe surface structures of laser-irradiated samples of highly oriented pyrolytic graphite (HOPG) have been investigated using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The samples were irradiated with a 30 ns ruby laser (λ = 6943 !A) pulse with energy fluences ranging from 0.1 to 3.0 J cm−2. Optically, the specimens show a damage region approximately 5 mm in diameter. The surface structure displays three characteristic regions: an outer boundary characterized by submicron carbon spheroids resting on the surface; an inner boundary characterized by both submicron spheroids and 1 to 5 [m ‘torn’ carbon layers which appear to have broken away from the graphite surface after irradiation; a central region characterized by a uniform density of spheroids and a pattern of surface upheavals which trace out a grain pattern similar to that of the pristine substrate. Electron diffraction patterns taken on the irradiated region indicate an ultra-fine grain 2-dimensionally ordered carbon. Qualitative trends in the areal density of different microstructural features are presented. In addition, a simple model explaining the observed features is given. All observations are consistent with the rapid solidification of liquid carbon.

The identification of magnetic minerals and other selfassembled structures within magnetotactic bacteria using Electron Microscopy and related micro-techniques

1992 ◽  
Vol 50 (2) ◽  
pp. 1022-1023
Author(s):  
Dennis A. Bazylinski ◽  
Anthony J. Garratt-Reed ◽  
Richard B. Frankel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Behavior ◽  
Magnetotactic Bacteria ◽  
Structural Features ◽  
Magnetic Minerals ◽  
Intracellular Iron ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Scanning Transmission

Magnetotactic bacteria are a diverse group of procaryotes whose direction of motility is influenced by magnetic fields. These organisms are ubiquitous in aquatic habitats and contain unique intracellular iron-rich membrane-bounded inclusions called magnetosomes that are responsible for the cells’ magnetic behavior. The composition, size (40-100 nm), morphology, position, and orientation of the particles appear to be highly controlled by these bacteria. Ferrimagnetic magnetite (Fe3O4), greigite (Fe3S4), and pyrrhotite (Fe7S8) and nonmagnetic pyrite (FeS2) have been identified as the mineral phases of the magnetosomes in different bacteria. These organisms also contain other intracellular structures that reflect aspects of their physiology, metabolism, and ecology. In order to determine the external structural features of cells and the composition and structure of their intracellular inclusions, transmission electron microscopy (TEM), scanning-transmission electron microscopy (STEM), energy-dispersive x-ray detection (EDXA), and selected area electron diffraction (SAED) techniques were employed.The results of a typical electron microscope (EM) and microanalytical study of a Fe3O4-producing magnetotactic bacterium is shown in Figures 1-4. This unidentified organism, designated strain MV-4, was isolated from sulfide-rich water and sediment collected from a salt marsh.

Nanostructural characterizations of hydrogen-permselective Si–Co–O membranes by transmission electron microscopy

2009 ◽  
Vol 24 (2) ◽  
pp. 372-378 ◽  
Author(s):  
Shinji Fujisaki ◽  
Koji Hataya ◽  
Tomohiro Saito ◽  
Shigeo Arai ◽  
Yuji Iwamoto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gas Permeation ◽  
Hydrogen Gas ◽  
Transmission Electron Microscopy Micrographs ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Diffraction Patterns ◽  
Permeation Properties

Nanostructural characterizations of liquid metal–organic precursors-derived cobalt-doped amorphous silica (Si–Co–O) membranes supported on a mesoporous anodic alumina capillary (MAAC) tube were performed to study their unique high-temperature hydrogen gas permeation properties. Cross-sectional scanning transmission electron microscopy images and selected-area electron diffraction patterns indicated that the metal cobalt and the different oxidation states of cobalt oxides (CoO and Co3O4) nanocrystallites having a size range of 5–20 nm were in situ formed in the mesopore channels of the MAAC tube. In addition, high-resolution transmission electron microscopy micrographs and electron energy loss spectroscopy elemental mapping images indicated that the highly dense Co-doped amorphous Si–O formed within the mesopore channels of the MAAC tube. These nanostructural features could contribute to the hydrogen-selective permeation properties observed for the membranes.

scholarly journals Obtaining and Characterization of TiO2-GO Composites for Photocatalytic Applications

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
D. K. Calvo Ramos ◽  
M. Vega González ◽  
R. A. Esparza Muñóz ◽  
J. Santos Cruz ◽  
F. J. De Moure-Flores ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Uv Radiation ◽  
Uv Light ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

Titanium dioxide (TD) and graphene oxide (GO) were synthesized by sol-gel and improved Hummers method, respectively. This study shows the results of the incorporation through four different conditions (sol-gel, sol-gel and ultrasonic, annealed, and UV radiation, C1 to C4, respectively). It was observed that a homogeneous incorporation of TD on sheets of GO was obtained satisfactorily. The composites of TiO2/GO were characterized using different techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and infrared spectroscopy (IR). The photocatalytic activity of the composites was determined from the degradation of the dye azo tartrazine using UV and solar radiation. The best incorporation of TD nanoparticles on GO was obtained with condition C3 (thermal incorporation method) at a temperature of 65°C. This shows a uniformity in the size and shape of the TD as well as an excellent adherence to the sheet of GO. This addition is accomplished by ionic bonding in the presence of electrostatic Coulomb forces. The C3 composite degraded the tartrazine dye using UV radiation and sunlight. With the latter, the degradation time was three times faster than using UV light.

Structural and Chemical Characterization of Yb2O3-ZrO2 System by HAADF-STEM and HRTEM

2009 ◽  
Vol 15 (1) ◽  
pp. 46-53 ◽  
Author(s):  
C. Angeles-Chavez ◽  
P. Salas ◽  
L.A. Díaz-Torres ◽  
E. de la Rosa ◽  
R. Esparza ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystalline Structure ◽  
Sol Gel ◽  
Tetragonal Zirconia ◽  
Chemical Characterization ◽  
Dark Field ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractZrO2:Yb3+ nanocrystalline phosphors with high concentrations of ytterbium ions were prepared using the sol-gel method. X-ray diffraction, high-angle annular-dark-field scanning transmission electron microscopy (HAADF-STEM), energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy (HRTEM) were used to characterize the nanocrystalline phosphors annealed at 1000°C. Unit-cell distortion and changes in the crystalline structure of the monoclinic zirconia to tetragonal zirconia, and subsequently cubic zirconia, were observed with increased Yb concentration. Yb ions were randomly distributed into the lattice of the crystalline structure. No segregation of Yb2O3 phase was observed. The substitution of Zr atoms by Yb atoms on different crystalline phases was confirmed by the experimental results and theoretical simulations of HRTEM and HAADF-STEM.

scholarly journals Automated Crystal Orientation Mapping by Precession Electron Diffraction-Assisted Four-Dimensional Scanning Transmission Electron Microscopy Using a Scintillator-Based CMOS Detector

2021 ◽  
Vol 27 (5) ◽  
pp. 1102-1112
Author(s):  
Jiwon Jeong ◽  
Niels Cautaerts ◽  
Gerhard Dehm ◽  
Christian H. Liebscher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Scanning Transmission Electron Microscopy ◽  
Angular Resolution ◽  
Transmission Electron ◽  
Orientation Mapping ◽  
Scanning Transmission ◽  
Precession Electron Diffraction ◽  
Diffraction Patterns

The recent development of electron-sensitive and pixelated detectors has attracted the use of four-dimensional scanning transmission electron microscopy (4D-STEM). Here, we present a precession electron diffraction-assisted 4D-STEM technique for automated orientation mapping using diffraction spot patterns directly captured by an in-column scintillator-based complementary metal-oxide-semiconductor (CMOS) detector. We compare the results to a conventional approach, which utilizes a fluorescent screen filmed by an external charge charge-coupled device camera. The high-dynamic range and signal-to-noise characteristics of the detector greatly improve the image quality of the diffraction patterns, especially the visibility of diffraction spots at high scattering angles. In the orientation maps reconstructed via the template matching process, the CMOS data yield a significant reduction of false indexing and higher reliability compared to the conventional approach. The angular resolution of misorientation measurement could also be improved by masking reflections close to the direct beam. This is because the orientation sensitive, weak, and small diffraction spots at high scattering angles are more significant. The results show that fine details, such as nanograins, nanotwins, and sub-grain boundaries, can be resolved with a sub-degree angular resolution which is comparable to orientation mapping using Kikuchi diffraction patterns.

scholarly journals Processing of Copper by Hydrostatic Extrusion – Studies of Microstructure and Properties

2016 ◽  
Vol 61 (3) ◽  
pp. 1575-1580
Author(s):  
B. Leszczyńska-Madej ◽  
M. W. Richert ◽  
I. Nejman ◽  
P. Zawadzka
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Statistical Analysis ◽  
Scanning Transmission Electron Microscopy ◽  
Pure Copper ◽  
Hydrostatic Extrusion ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Diffraction Patterns

AbstractThe present study attempts to apply HE to 99.99% pure copper. The microstructure of the samples was investigated by both light microscopy and scanning transmission electron microscopy (STEM). Additionally, the microhardness was measured, the tensile test was made, and statistical analysis of the grains and subgrains was performed. Based on Kikuchi diffraction patterns, misorientation was determined. The obtained results show that microstructure of copper deformed by hydrostatic extrusion (HE) is rather inhomogeneous. The regions strongly deformed with high dislocation density exist near cells and grains/subgrains free of dislocations. The measurements of the grain size have revealed that the sample with an initial in annealed-state grain size of about 250 μm had this grain size reduced to below 0.35μm when it was deformed by HE to the strain ε=2.91. The microhardness and UTS are stable within the whole investigated range of deformation.

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