Search results for "proper"
showing 10 items of 3167 documents
Advanced strategy to exploit wine-making waste by manufacturing antioxidant and prebiotic fibre-enriched vesicles for intestinal health.
2020
Grape extract-loaded fibre-enriched vesicles, nutriosomes, were prepared by combining antioxidant extracts obtained from grape pomaces and a prebiotic, soluble fibre (Nutriose®FM06). The nutriosomes were small in size (from ∼140 to 260 nm), homogeneous (polydispersity index < 0.2) and highly negative (∼ −79 mV). The vesicles were highly stable during 12 months of storage at 25 °C. When diluted with warmed (37 °C) acidic medium (pH 1.2) of high ionic strength, the vesicles only displayed an increase of the mean diameter and a low release of the extract, which were dependent on Nutriose concentration. The formulations were highly biocompatible and able to protect intestinal cells (Caco-2) fro…
Characterization of a new natural fiber from Arundo donax L. as potential reinforcement of polymer composites.
2013
Abstract The aim of this paper is to study the possibility of using of Arundo donax L. fibers as reinforcement in polymer composites. The fibers are extracted from the outer part of the stem of the plant, which widely grows in Mediterranean area and is diffused all around the world. To use these lignocellulosic fibers as reinforcement in polymer composites, it is necessary to investigate their microstructure, chemical composition and mechanical properties. Therefore, the morphology of A. donax L. fibers was investigated through electron microscopy, the thermal behavior through thermogravimetric analysis and the real density through a helium pycnometer. The chemical composition of the natura…
Elektrónová a pásová štruktúra CuMnAs študovaná optickou a fotoemissinou spektroskopiou
2017
Tetragonal phase of CuMnAs progressively appears as one of the key materials for antiferromagnetic spintronics due to efficient current-induced spin-orbit torques whose existence can be directly inferred from crystal symmetry. Theoretical understanding of spintronic phenomena in this material, however, relies on the detailed knowledge of electronic structure (band structure and corresponding wave functions) which has so far been tested only to a limited extent. We show that AC permittivity (obtained from ellipsometry) and UV photoelectron spectra agree with density functional calculations. Together with the x-ray diffraction and precession electron diffraction tomography, our analysis confi…
Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration
2013
Catalytic and catalytic photo-assisted hydration of propene to form 2-propanol in gas–solid regime at atmospheric pressure and 85 1C were carried out by using a heteropolyacid (POM) supported on different oxides. Binary materials were prepared by impregnation of H3PW12O40 on different commercial and home prepared supports (TiO2, SiO2, WO3, ZrO2, ZnO, Al2O3). Some of the composites were active both for catalytic and catalytic photo-assisted reactions. The Keggin type POM was completely and partially degraded, when supported on ZnO and Al2O3, respectively, and these binary solids always resulted as inactive for both catalytic and catalytic photo-assisted reactions. The supported Keggin POM sp…
Structural and electrical study of the topological insulator SnBi2Te4 at high pressures
2016
We report high-pressure X-ray diffraction and electrical measurements of the topological insulator SnBi2Te4 at room temperature. The pressure dependence of the structural properties of the most stable phase of SnBi2Te4 at ambient conditions (trigonal phase) have been experimentally determined and compared with results of our ab initio calculations. Furthermore, a comparison of SnBi2Te4 with the parent compound Bi2Te3 shows that the central TeSnTe trilayer, which substitutes the Te layer at the center of the TeBiTeBiTe layers of Bi2Te3, plays a minor role in the compression of SnBi2Te4. Similar to Bi2Te3, our resistance measurements and electronic band structure simulations in SnBi2Te4 at hi…
Experimental and theoretical study of the energetic, morphological, and photoluminescence properties of CaZrO3:Eu3+
2018
In this study, we present a combined experimental and theoretical study of the geometry, electronic structure, morphology, and photoluminescence properties of CaZrO3:Eu3+ materials. The polymeric precursor method was employed to synthesize CaZrO3:Eu3+ crystals, while density functional theory calculations were performed to determine the geometrical and electronic properties of CaZrO3:Eu3+ in its ground and excited electronic states (singlet and triplet). The results were combined with X-ray diffraction (XRD) measurements to elucidate the local structural changes induced by the introduction of Eu3+ in the crystal lattice. This process results in the formation of intermediate levels in the ba…
Backward transition radiation in the extreme ultraviolet region as a tool for the transverse beam profile diagnostic
2014
The present article summarizes the results of two experiments which were performed to study the radiation properties of backward transition radiation (BTR) in the extreme ultraviolet (EUV) region. This wavelength region is of particular interest for transverse beam profile imaging, because the spatial resolution is improved as a result of the reduced contribution in the imaging process of the fundamental diffraction limit. In addition, the influence of coherent effects in the transition radiation emission process, which have been observed in the visible region, might be mitigated. The first experiment, dedicated to the investigation of the BTR angular characteristics, indicates that the rad…
Structural and elastic properties of defect chalcopyrite HgGa2S4 under high pressure
2014
In this work, we focus on the study of the structural and elastic properties of mercury digallium sulfide (HgGa2S4) at high pressures. This compound belongs to the family of AB(2)X(4) ordered-vacancy compounds and exhibits a tetragonal defect chalcopyrite structure. X-ray diffraction measurements at room temperature have been performed under compression up to 15.1 GPa in a diamond anvil cell. Our measurements have been complemented and compared with ab initio total energy calculations. The axial compressibility and the equation of state of the low-pressure phase of HgGa2S4 have been experimentally and theoretically determined and compared to other related ordered-vacancy compounds. The pres…
Investigation of AC Electrical Properties of MXene-PCL Nanocomposites for Application in Small and Medium Power Generation
2021
The paper examined Ti3C2Tx MXene (T—OH, Cl or F), which is prepared by etching a layered ternary carbide Ti3AlC2 (312 MAX-phase) precursor and deposited on a polycaprolactone (PCL) electrospun membrane (MXene-PCL nanocomposite). X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM) indicates that the obtained material is pure Ti3C2 MXene. SEM of the PCL-MXene composite demonstrate random Ti3C2 distribution over the nanoporous membrane. Results of capacitance, inductance, and phase shift angle studies of the MXene-PCL nanocomposite are presented. It was found that the frequency dependence of the capacitance exhibited a clear sharp minima in the frequency range of 50 Hz to o…
High-pressure structural, elastic, and thermodynamic properties of zircon-type HoPO4 and TmPO4
2017
[EN] Zircon-type holmium phosphate (HoPO4) and thulium phosphate (TmPO4) have been studied by single-crystal x-ray diffraction and ab initio calculations. We report on the influence of pressure on the crystal structure, and on the elastic and thermodynamic properties. The equation of state for both compounds is accurately determined. We have also obtained information on the polyhedral compressibility which is used to explain the anisotropic axial compressibility and the bulk compressibility. Both compounds are ductile and more resistive to volume compression than to shear deformation at all pressures. Furthermore, the elastic anisotropy is enhanced upon compression. Finally, the calculation…