Search results for "Microscope"

Behaviour of advanced tritium breeder pebbles under simultaneous action of accelerated electrons and high temperature

2017

The authors greatly acknowledge the technical and experimen-tal support of O. Valtenbergs and L. Avotina (Institute of Chemical Physics, University of Latvia). The work is performed in the frames of the University of Latvia financed project No. Y9-B044-ZF-N-300, “Nano, Quantum Technologies, and Innovative Materials for Eco-nomics”.

MOCVD growth of TiO2 thin films on single crystal GaAs substrates

2000

Abstract TiO 2 thin films have been grown on (100)GaAs and (111)GaAs substrates by low-pressure metal organic chemical vapour deposition (LP-MOCVD). Titanium(IV) isopropoxide, Ti{OCH(CH 3 ) 2 } 4 , was used as a precursor and TiO 2 films were obtained without an additional oxygen flux. Scanning electron microscopy (SEM) experiments have shown a well ordered rod-like crystallisation in the films grown on (100)GaAs. This ordered crystallisation was favoured by a high deposition temperature ( T d =700°C). By contrast, no distinct order was observed in the films grown on (111)GaAs substrates. X-ray diffraction patterns revealed a mainly rutile structure for the TiO 2 films deposited on (100)GaA…

Mechanism of Formation of TiO2-Doped Mullites from Heated Single-Phase Gels Investigated by Structural and Microstructural Parameters

2008

An analysis of the microstructure of TiO 2 -doped mullites prepared from monophasic gels thermally treated in the temperature range 900°-1600°C is reported. Two series of gels with nominal compositions 3(Al 2-x Ti x O 3 ) ·2(SiO 2 ) and 2(Al 2-x Ti x O 3 )·(SiO 2 ), in the range 0≤x≤0.15, were prepared. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to follow the structural and textural evolution from gels to the final doped mullites. The crystallite sizes and microstrains were determined by linewidth refinements of XRD patterns using the integral breadth method of Langford and the Warren-Averbach analysis. XRD patterns showed the formation of Al 2 TiO 5 and…

Incremental lines in root cementum of human teeth: an approach to their ultrastructural nature by microscopy.

1998

In ground sections of human teeth, root cementum shows under the light microscope as alternating, almost concentric, dark and light rings. In paleontology and forensic medicine, the number of these incremental lines or annulations is used to derive the age-at-death of the individual. To find the ultrastructural features underlying these cemental annulations, we used bright-field light microscopy (LM), confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM), and electron-dispersive x-radiation (EDX) in a scanning electron microscope (SEM). Annulations visible in ground sections of about 100-μm thickness were no longer visible in semi-thin sections (thickness, 1-2 μ…

Synthesis of niobium aluminides using mechanically activated self-propagating high-temperature synthesis and mechanically activated annealing process

1999

The mechanically activated self-propagating high-temperature synthesis (MASHS) technique and the mechanically activated annealing process (M2AP) were used to produce NbAl3 intermetallic compound. The MASHS process results from the combination of two steps: first, a mechanical activation of the Nb 3Al powders mixture; second, a self-propagating high-temperature synthesis (SHS). The M2AP process also results from the combination of two steps: the first is the same; the second consists of the annealing of as-milled powders. Based on X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDXS), the as-milled powders, MASHS, and M2AP end-pr…

Room temperature electrodeposition of photoactive Cd(OH)2 nanowires

2009

Cd(OH)2 nanowires (NWs) were successfully prepared by room temperature electrogeneration of base using Cd(NO3)2 aqueous electrolyte and Anodic Alumina Membrane (AAM) as template. Cd(OH)2 films have been also deposited on tin-doped indium oxide (ITO) for comparison. SEM analysis shows high quality deposits made of closely packed nanowires (NWs) into AAM and uniform flake-like surface on ITO. XRD analysis reveals that Cd(OH)2 films on ITO are polycrystalline, while the nanowires grow along the preferential directions [100] and [110]. Photoelectrochemical measurements show that Cd(OH)2 NWs are photoactive materials with indirect and direct band gap of 2.15 and 2.75 eV, respectively. Keywords: …

Mikromorphometrie und Stereographie des Rauhtiefenreliefs beschichteter Implantatoberflächen durch Rasterelektronenmikroskopie und konfokale Laser-Sc…

1998

Aging resistance of bio-epoxy jute-basalt hybrid composites as novel multilayer structures for cladding

2017

Abstract Aging resistance of jute reinforced laminates is compared with two jute/basalt hybrid laminates prepared with different stacking sequences (i.e., sandwich and intercalated configuration). To this aim, composites are exposed to cyclic conditions comprising hygrothermal stress and UV radiation to promote an accelerated aging, for a period of 84 days. Specimens of each laminate are tested after 14, 28, 56 and 84 days, respectively. Quasi-static flexural tests, Charpy impact tests and dynamic mechanical tests are performed according to international ASTM and ISO standards. Furthermore, scanning electron microscopy and differential scanning calorimetry are used to evaluate the morpholog…

Nucleant layer effect on nanocolumnar ZnO films grown by electrodeposition

2013

Different ZnO nanostructured films were electrochemically grown, using an aqueous solution based on ZnCl2, on three types of transparent conductive oxides grow on commercial ITO (In2O3:Sn)-covered glass substrates: (1) ZnO prepared by spin coating, (2) ZnO prepared by direct current magnetron sputtering, and (3) commercial ITO-covered glass substrates. Although thin, these primary oxide layers play an important role on the properties of the nanostructured films grown on top of them. Additionally, these primary oxide layers prevent direct hole combination when used in optoelectronic devices. Structural and optical characterizations were carried out by scanning electron microscopy, atomic for…

Wettability of MXene and its interfacial adhesion with epoxy resin

2021

Abstract The surface energies of MXene nanofillers critically affect the mechanical properties and durability of any polymer-based devices and composites to which these fillers are applied. In this context, this study comprehensively investigates Ti3C2Tz MXenes prepared via the hydrochloric acid/lithium fluoride etching of Ti3AlC2. The surface energy values of 10-layer MXene coatings were evaluated to be between 47.98 and 64.48 mJ/m2 as per contact-angle measurements. The wettability properties were found to depend on the number of coating layers and the liquids used. Additionally, the coating roughness was evaluated by using atomic force microscopy. The effectiveness of MXenes as a reinfor…