Search results for "osi"
showing 10 items of 45335 documents
Plastic yielding of glass in high-pressure torsion apparatus
2018
International audience; Hardness measurements performed at room temperature have demonstrated that glass can flow under elevated pressure, whereas the effect of high pressure on glass rheology remains poorly quantified. Here, we applied a high-pressure torsion (HPT) apparatus to deform SCHOTT SF6 â glass and attempted to quantify the effect of pressure and temperature on the shear deformation of glass subjected to pressures from 0.3 GPa to 7 GPa and temperatures from 25 ℃ to 496 ℃. Results show that the plastic yield deformation was occurring during the HPT experiments on the SF6 glass at elevated temperature from 350 ℃ to 496 ℃. The yield stress of SF6 glass decreases with increasing tempe…
Batch-to-Melt Conversion Kinetics in Sodium Aluminosilicate Batches Using Different Alumina Raw Materials
2016
The batch-to-melt conversion in batches of sand, soda ash and corundum (C), alumina spinel (A), boehmite (B), or gibbsite (G) as Al2O3 carrier are studied using thermal analysis, X-ray diffraction, and 27Al nuclear magnetic resonance spectroscopy. Laboratory-scaled batches are either heated continuously or quenched from 1600°C in a series of increasing dwell times. The results show that the conversion from the raw materials to the fresh melt proceeds in two kinetic stages. During the first stage (3–5 min), fast conversion of nearly 95% by mass occurs and the conversion coefficient increases in the order G < C ≈ A < B. The second stage is controlled by the slow dissolution of intermediate cr…
The filter and calibration wheel for the ATHENA wide field imager
2016
The planned filter and calibration wheel for the Wide Field Imager (WFI) instrument on Athena is presented. With four selectable positions it provides the necessary functions, in particular an UV/VIS blocking filter for the WFI detectors and a calibration source. Challenges for the filter wheel design are the large volume and mass of the subsystem, the implementation of a robust mechanism and the protection of the ultra-thin filter with an area of 160 mm square. This paper describes performed trade-offs based on simulation results and describes the baseline design in detail. Reliable solutions are envisaged for the conceptual design of the filter and calibration wheel. Four different varian…
Dielectric response of BaTiO3 electronic states under AC fields via microsecond time-resolved X-ray absorption spectroscopy
2021
Abstract For the first time, the dielectric response of a BaTiO 3 thin film under an AC electric field is investigated using microsecond time-resolved X-ray absorption spectroscopy at the Ti K-edge in order to clarify correlated contributions of each constituent atom on the electronic states. Intensities of the pre-edge e g peak and shoulder structure just below the main edge increase with an increase in the amplitude of the applied electric field, whereas that of the main peak decreases in an opposite manner. Based on the multiple scattering theory, the increase and decrease of the e g and main peaks are simulated for different Ti off-center displacements. Our results indicate that these s…
Guest Editorial
2019
Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²
Correlative study of structural and optical properties of ZnSe under severe plastic deformation
2019
The effect of plastic deformation on the optical and structural properties of ZnSe crystals has been investigated. The optical properties have been monitored by cathodoluminescence measurements as a function of the deformation degree. Remarkable differences in the defect-related emissions from the most severely deformed areas have been encountered. Deformation of the crystal lattice of ZnSe, associated with slip phenomena, has been studied by means of Electron Backscattered Diffraction and micro-Raman spectroscopy. The relation between the deformation and the optical properties of the ZnSe crystals has been described.
Superparamagnetic recoverable flowerlike Fe3O4@Bi2O3 core–shell with g-C3N4 sheet nanocomposite: synthesis, characterization, mechanism and kinetic s…
2019
In the present research study, a simple method was developed for the synthesis of three-dimensional flowerlike Fe3O4@Bi2O3 core–shell with g-C3N4 sheet nanocomposites. The X-ray diffraction, Fourier transform infrared spectroscopy, scanning electronic microscopy, transmission electron microscope, vibrating sample magnetometer, dynamic laser scattering analyzer and UV–Vis diffuse reflection spectroscopy were employed for the characterization of structure, purity and morphology of the resultant samples. The degradation of indigo carmine as a model of organic dye pollutant is applied for photo-catalytic activity. The parameters which are affecting the efficiency of various parameters, such as;…
Complex structural contribution of the morphotropic phase boundary in Na0.5Bi0.5TiO3 - CaTiO3 system
2019
Abstract The correlation between structure and dielectric properties of lead-free (1-x)Na0.5Bi0.5TiO3 - xCaTiO3 ((1-x)NBT - xCT) polycrystalline ceramics was investigated systematically by X-ray diffraction, combined with impedance spectroscopy for dielectric characterizations. The system shows high miscibility in the entire composition range. A morphotropic phase boundary (MPB), at 0.09 ≤ x
Effect of Cu doping on Ba0.95Pb0.05TiO3 electrical properties studied by means of electrical impedance spectroscopy
2019
The ceramics of 0.95BaTiO3–0.05PbTiO3+Xwt.%CuO (X = 0.05, 0.1, 1, 3) were prepared by a solid phase reaction. The structural and morphology studies were carried out by means of X-ray diffraction te...
Neutron scattering and imaging: a tool for archaeological studies
2015
International audience; Neutron scattering and neutron imaging are powerful techniques for studying the structure of objects without damage, which is an essential prerequisite for investigations in Cultural Heritage domain, particularly in Archaeology. The deep penetration of neutrons in most materials allows for the study of relatively large objects. The contrast between similar materials, like metals in alloys, or that due to the presence of hydrogen atoms gives information about the internal structure of objects that have been modified or repaired in the past. Imaging and tomography give a 3-dimensional view of the whole object, permitting discrimination between different parts of the ob…