Search results for " edge"
showing 10 items of 226 documents
Study of Photo-Induced Thin Film Growth on Cds Substrates.*
1983
ABSTRACTPhoto-induced growth of ZnS on CdS has been studied using amorphous (thin film) and single-crystal substrates. The effect has been found to occur for light of wavelength shorter than the CdS absorption edge; a maximum light-induced thickness enhancement of 700 Å has been obtained for the ZnS film, with a growth rate of 2000 Å/min. The lightinduced growth, with its observed “memory” of several minutes is consistent with photo-desorption of an adlayer.
X-ray absorption study of the electronic structure of tungsten and molybdenum oxides on the O K-edge
2001
Magnetron sputtered amorphous thin films a-WO3, a-MoO3 and doped a-WO3:Ir have been studied by X-ray absorption spectroscopy on the oxygen K-edge in comparison with crystalline oxides as monoclinic m-WO3, orthorhombic α-MoO3, cubic Na0.6WO3, layered-type hexagonal h-WO3 and WO3·H2O, having variable electronic and atomic structure. The changes in the XANES ranging 10–15 eV above the absorption edge are interpreted based on the known band-structure calculations. The high-energy features are related to the multiple-scattering processes (EXAFS) at the nearest atoms.
ATHENA X-IFU thermal filters development status toward the end of the instrument phase-A
2018
Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The X-ray Integral Field Unit (X-IFU) is one of the two instruments of the Athena astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Programme. The X-IFU consists of a large array of transition edge sensor micro-calorimeters that will operate at 100 mK inside a sophisticated cryostat. A set of thin filters, highly transparent to X-rays, will be m…
Transition-edge sensor array development
2009
Local Structure of Supported Keggin and Wells-Dawson Heteropolyacids and Its Influence on the Catalytic Activity
2019
[EN] Keggin [PW12O40]3– and Wells–Dawson [P2W18O62]6– heteropolyanions are nanosized transition-metal-oxygen clusters belonging to the heteropolyacids (HPAs) family. They are widely used as catalysts due to their high Brønsted acidity, and their dispersion on solid supports favors the accessibility to their acid sites generally increasing the catalytic activity. A series of binary materials composed of Keggin or Wells–Dawson HPAs and SiO2, TiO2, and ZrO2 have been prepared by impregnation or solvothermal methods. Remarkable differences have been found in the catalytic activities among the unsupported and supported HPAs. These differences have been correlated in the past to the structural ch…
Large 256-Pixel X-ray Transition-Edge Sensor Arrays With Mo/TiW/Cu Trilayers
2015
We describe the fabrication and electrical characterization of 256-pixel X-ray transition-edge sensor (TES) arrays intended for materials analysis applications. The processing is done on 6-in wafers, providing capabilities on a commercial scale. TES films were novel proximity coupled Mo/TiW/Cu trilayers, where the thin TiW layer in between aims to improve the stability of the devices by preventing unwanted effects such as Mo/Cu interdiffusion. The absorber elements were electrodeposited gold of thickness 2 μm. The single-pixel design discussed here is the so-called Corbino geometry. Most design goals were successfully met, such as the critical temperature, thermal time constant, and transit…
Design and optimization of the wide-field spectrometer for EDGE mission
2007
Comparative Experimental and Theoretical Study of the Fe L-2,L-3-Edges X-ray Absorption Spectroscopy in Three Highly Popular, Low-Spin Organoiron Com…
2019
The occupied and unoccupied electronic structures of three highly popular, closed shell organoiron complexes ([Fe(CO)(5)], [(eta(5)-C5H5 )Fe(CO)(mu-CO)](2), and [(eta(5)-C5H5)(2)Fe]) have been theoretically investigated by taking advantage of density functional theory (DFT) calculations coupled to the isolobal analogy (Elian et al. Inorg. Chem. 1976, 15, 1148). The adopted approach allowed us to look into the relative role played by the ligand -> Fe donation and the Fe -> ligand back-donation in title molecules, as well as to investigate how CO- (terminal or bridging) and [(eta(5)-C5H5)](-)-based pi* orbitals compete when these two ligands are simultaneously present as in [(eta(5)-C5H…
No performance reduction at the present northern edge of Ambrosia artemisiifolia L. invasion range
2014
Plant populations at range edges may exhibit reduction of performances and fitness. In the case of biological invasions, such a reduction could be associated with a slowing down of the spread and explain the non-naturalization of a species outside its present invasion range. Common ragweed (Ambrosia artemisiifolia L.) is an ideal model to investigate such processes, since it is invasive in France but not naturalized in northern countries, such as Belgium and the Netherlands. In this study, we test if the performances of ragweed populations vary among different invasion zones. Three populations were selected in each of four invasion zones in Western Europe: 1) French invasion area; 2) northe…