Search results for "engineer"
showing 10 items of 44296 documents
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;…
A consistent path for phase determination based on transmission electron microscopy techniques and supporting simulations.
2018
This work addresses aspects for the analysis of industrial relevant materials via transmission electron microscopy (TEM). The complex phase chemistry and structural diversity of these materials require several characterization techniques to be employed simultaneously; unfortunately, different characterization techniques often lack connection to yield a complete and consistent picture. This paper describes a continuous path, starting with the acquisition of 3D diffraction data - alongside classical high-resolution imaging techniques - and linking the structural characterization of hard metal industrial samples with energy-loss fine-structure simulations, quantitative electron energy-loss (EE…
Preparation, Characterisation and Dielectric Properties of YBa2Cu3O7-δ/ Insulator-Heterostructures
1996
YBa 2 Cu 3 O 7-δ /insulator/Au-heterostructures on SrTiO 3 or LaAlO 3 substrates were prepared to study the properties of the materials SrTiO 3 , BaTiO 3 and Ceo 2 . X-ray diffraction measurements in Bragg-Brentano geometry show c-axis-oriented growth for the superconductor and the insulators SrTiO 3 and CeO 2 . Typical values for the rocking curve width of the different insulating films are between 0.4° and 0.8°. The highest breakdown fields are measured for the insulator SrTiO 3 with +37.5 kV/mm and -8.8 kV/mm. The permittivity for CeO 2 is independent of applied field and only weakly temperature dependent. This is in contrast to the perovskite type insulators, where the permittivity depe…
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...
Bandgap behavior and singularity of the domain-induced light scattering through the pressure-induced ferroelectric transition in relaxor ferroelectri…
2018
[EN] In this letter, we have investigated the electronic structure of A(x)Ba(1-x)Nb(2)O(6) relaxor ferroelectrics on the basis of optical absorption spectroscopy in unpoled single crystals with A = Sr and Ca under high pressure. The direct character of the fundamental transition could be established by fitting Urbach's rule to the photon energy dependence of the absorption edge yielding bandgaps of 3.44(1) eV and 3.57(1) eV for A = Sr and Ca, respectively. The light scattering by ferroelectric domains in the pre-edge spectral range has been studied as a function of composition and pressure. After confirming with x-ray diffraction the occurrence of the previously observed ferroelectric to pa…
Analog isolated electronic dynamometer based on a magnetoresistive current sensor.
2017
In this work, an electronic system is presented to measure the force applied by a solenoid. The originality of the work is focused on the use of a magnetoresistive current sensor to provide the isolation barrier needed in the actual industrial plant where the solenoids are working. The design of the electronic system is presented as well as experimental measurements as a result of a calibration process showing a negligible hysteresis with that specific sensor. The magnetoresistive current sensor is used to develop transmission functions rather than playing its usual sensing roles.
From EFTA to EC/EU and Back to EFTA? The European Economic Area (EEA) As a Possible Scenario for the UK-EU Relations After Brexit
2018
Brexit is announced to take place and it appears, that the most probable scenario for the UK is the “Norway-Option”, i.e., to (again) become a member of the European Free Trade Association (EFTA) and join the EEA. The chapter identifies the major claims of the leave-campaign to analyse, whether by doing so, the Brexit proponents will achieve what they campaigned for. Furthermore, the paper explains the functioning of the EEA, exploring the potential changes for the UK, the EU, and the EEA/EFTA.
Nonlinear optical response of bulk ZnO crystals with different content of intrinsic defects
2018
Abstract The nonlinear optical (NLO) properties of native defect-rich ZnO single crystals were studied in details within the excitation of the continuous wave (CW) and pulsed laser radiation at 532 nm (2.33 eV). Analysis of the experimental data of optical elastic scattering, Fourier transform infrared (FTIR), near infrared–visible–ultraviolet (NIR–Vis–UV) spectra recorded in reflection and absorption modes, and data of photoluminescence (PL) spectroscopy confirmed the contribution of both intrinsic defects and their clusters, being determined before by neutron diffraction and XRD analysis. It was shown that the high sensitivity of the NLO diagnostics via self-action of a laser beam is due …
RBS and ERD cross-sections and optical model parameters for the analysis of lithium, boron and nickel
2000
Abstract Elastic scattering cross-sections for RBS analysis of nickel by 7 Li and 11 B ion backscattering near the Coulomb barrier have been determined. The lithium ion measurements were performed in the energy range of 8–15 MeV at the laboratory angles of 115° and 135°. For boron ions the energies between 14 and 24 MeV and scattering angles of 89°, 110° and 130° were used. For the analysis of lithium and boron by ERD the scattering cross-sections have been calculated by kinematically reversing the backscattering process. The calculated 58 Ni ion energies thus varied between 65 and 125 MeV for lithium and between 75 and 130 MeV for boron recoils. For the Li + Ni and B + Ni systems the thres…