Search results for "ZINC"
showing 10 items of 1081 documents
High-density ZnO Nanowires as a Reversible Myogenic-Differentiation-Switch
2018
Mesoangioblasts are outstanding candidates for stem-cell therapy and are already being explored in clinical trials. However, a crucial challenge in regenerative medicine is the limited availability of undifferentiated myogenic progenitor cells because growth is typically accompanied by differentiation. Here reversible myogenic-differentiation switching during proliferation is achieved by functionalizing the glass substrate with high-density ZnO nanowires (NWs). Specifically, mesoangioblasts grown on ZnO NWs present a spherical viable undifferentiated cell state without lamellopodia formation during the entire observation time (8 days). Consistently, the myosin heavy chain, typically express…
Aromaticity and planarity of zinc phthalocyanine (ZnPc) characterized by splitting of NICS(1) index
2018
The planarity of zinc phthalocyanine (ZnPc) in the gas phase and water, with solute-solvent interactions modeled by polarized continuum model (PCM), has been characterized with new indexes of aromaticity. The aromaticity of individual ring subunits of ZnPc molecule was studied on the basis of nucleus independent chemical shift index (NICS) above and below the molecular plane. Density functional theory (DFT) with selected Pople-type basis sets was used to study the local aromaticity. The calculated NICS(1) and NICS(-1) indexes of aromaticity for a non-planar ZnPc molecule in the polar environment are significantly different.
Supramolecular capping-ligand effect of lamellar silica mesostructures for the one-pot synthesis of highly dispersed ZnO nanoparticles
2006
ZnO?SiO2 lamellar nanocomposites with high zinc content (5?Si/Zn?50) have been synthesized through a one-pot surfactant-assisted procedure from aqueous solution and starting from molecular atrane complexes of Zn and Si as inorganic hydrolytic precursors. This approach allows optimization of the dispersion of the ZnO nanodomains in the silica sheets. The nature of the layered silica materials has been confirmed by x-ray diffraction. Spectroscopic (ultraviolet?visible and photoluminescence) study of these layered silica materials shows that, regardless of the Si/Zn ratio, Zn atoms are organized in well-dispersed, uniform ZnO nanodomains (about 1.2?nm) partially embedded within the silica shee…
On the role of multi-functional polyhedral oligomeric silsesquioxane in polystyrene-zinc oxide nanocomposites
2014
Abstract Multi-functional trisilanol phenyl (TSPH) and trisilanol isobutyl (TSIB) polyhedral oligomeric silsesquioxane (POSS) have been used in the formulation of advanced polystyrene (PS)-zinc oxide (ZnO) nanocomposites. The neat matrix and PS/ZnO-based nanocomposites have been characterized through rheological, morphological, mechanical, and dynamic thermo-mechanical analysis. Both TSPH and TSIB are able to improve the dispersion of ZnO into the polystyrene matrix; furthermore, adding TSIB leads to better results because it facilitates better solubility into the PS matrix and interaction/reaction with the ZnO nanopowder. Finally, the optical properties and photo-oxidative resistance of th…
Formation of ZnO nanowires by anodization under hydrodynamic conditions for photoelectrochemical water splitting
2020
[EN] The present work studies the influence of hydrodynamic conditions (from 0 to 5000 rpm) during Zn anodization process on the morphology, structure and photoelectrocatalytic behavior of ZnO nanostructures. For this purpose, analysis with Confocal Laser-Raman Spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and photoelectrochemical water splitting tests were performed. This investigation reveals that hydrodynamic conditions during anodization promoted the formation of ordered ZnO nanowires along the surface that greatly enhance its stability and increases the photocurrent density response for water splitting in a 159% at the 5000 rpm electrode rotation speed.
Structural characterization of one-dimensional ZnO-based nanostructures grown by MOCVD
2010
Various one-dimensional (1D) ZnO-based nanostructures, including ZnO nano-wires (NWs) grown using vapour-liquid-solid (VLS) process, ZnO/ZnSe core/shell, nitrogen-doped ZnO and ZnMgO NWs were grown by metalorganic chemical vapour deposition (MOCVD). Transmission electron microscopy (TEM) analysis is presented. For all the samples, a high crystalline quality is observed. Some features are emphasized such as the gold contamination of ZnO wires grown under the metal droplets in the VLS process. It is concluded that MOCVD is a suitable technique for the realization of original ZnO nanodevices.
Recent advances in the development of high-resolution 3D cadmium-zinc-telluride drift strip detectors.
2020
In the last two decades, great efforts have been made in the development of 3D cadmium–zinc–telluride (CZT) detectors operating at room temperature for gamma-ray spectroscopic imaging. This work presents the spectroscopic performance of new high-resolution CZT drift strip detectors, recently developed at IMEM-CNR of Parma (Italy) in collaboration with due2lab (Italy). The detectors (19.4 mm × 19.4 mm × 6 mm) are organized into collecting anode strips (pitch of 1.6 mm) and drift strips (pitch of 0.4 mm) which are negatively biased to optimize electron charge collection. The cathode is divided into strips orthogonal to the anode strips with a pitch of 2 mm. Dedicated pulse processing analysis…
Room-temperature performance of 3 mm-thick cadmium-zinc-telluride pixel detectors with sub-millimetre pixelization.
2020
Cadmium–zinc–telluride (CZT) pixel detectors represent a consolidated choice for the development of room-temperature spectroscopic X-ray imagers, finding important applications in medical imaging, often as detection modules of a variety of new SPECT and CT systems. Detectors with 3–5 mm thicknesses are able to efficiently detect X-rays up to 140 keV giving reasonable room-temperature energy resolution. In this work, the room-temperature performance of 3 mm-thick CZT pixel detectors, recently developed at IMEM/CNR of Parma (Italy), is presented. Sub-millimetre detector arrays with pixel pitch less than 500 µm were fabricated. The detectors are characterized by good room-temperature performan…
Muon Knight shift at a structural defect in zinc crystals
1984
The interaction of a light hydrogen isotope with a structural defect is traced for the first time by means of the temperature dependence of the muon Knight shiftKμ in the hcp metal Zn. A surprising result is the huge and negativeKμ (−520 ppm) at the defect site, probably a multivacancy cluster.
Room-Temperature X-ray response of cadmium-zinc-Telluride pixel detectors grown by the vertical Bridgman technique
2020
In this work, the spectroscopic performances of new cadmium–zinc–telluride (CZT) pixel detectors recently developed at IMEM-CNR of Parma (Italy) are presented. Sub-millimetre arrays with pixel pitch less than 500 µm, based on boron oxide encapsulated vertical Bridgman grown CZT crystals, were fabricated. Excellent room-temperature performance characterizes the detectors even at high-bias-voltage operation (9000 V cm−1), with energy resolutions (FWHM) of 4% (0.9 keV), 1.7% (1 keV) and 1.3% (1.6 keV) at 22.1, 59.5 and 122.1 keV, respectively. Charge-sharing investigations were performed with both uncollimated and collimated synchrotron X-ray beams with particular attention to the mitigation o…