Search results for "energy-dispersive X-ray"
showing 10 items of 30 documents
Analytical study by SEM/EDX and metallographic techniques of materials used in the iron production process during the iberian period
2002
Abstract This work is the archaeometric study of different types of materials used in iron production in the Iberian Period (6th–2nd century b.c.). The materials were recovered in several archaeological digs (which makes it possible to date the archaeological remains) on different sites in the Levante area of the Iberian Peninsula. The samples selected for this study belong to different materials used in the ancient iron production process such as ores, slags, finished objects, etc. The use of scanning electron microscopy (SEM) is proposed to observe surface images of the samples to determine their morphological, microstructural and topographic characteristics to obtain valuable information…
Measurement and control of electron wave packets from a single-electron source
2015
We report an experimental technique to measure and manipulate the arrival-time and energy distributions of electrons emitted from a semiconductor electron pump, operated as both a single-electron source and a two-electron source. Using an energy-selective detector whose transmission we control on picosecond time scales, we can measure directly the electron arrival-time distribution and we determine the upper bound to the distribution width to be 30 ps. We study the effects of modifying the shape of the voltage wave form that drives the electron pump, and show that our results can be explained by a tunneling model of the emission mechanism. This information was in turn used to control the em…
Salt accumulation and effects within foliage of Tilia × vulgaris trees from the street greenery of Riga, Latvia
2020
International audience; Green infrastructures within sprawling cities provide essential ecosystem services, increasingly undermined by environmental stress. The main objective in this study was to relate the allocation patterns of NaCl contaminants to injury within foliage of lime trees mechanistically and distinguish between the effects of salt and other environmental stressors. Using field material representative of salt contamination levels in the street greenery of Riga, Latvia, the contribution of salt contaminants to structural and ultrastructural injury was analyzed, combining different microscopy techniques. On severely salt-polluted and dystrophic soils, the foliage of street lime …
Micromorphological approach to the systematics of Mediterranean Isoëtes species (Isoëtaceae, Lycopodiophyta): analysis of the megaspore surface
2012
Megaspore ornamentation is one of the few morphological characters used in the taxonomy of the genus Isoëtes. In the present work, we test the application of this character for distinguishing some Isoëtes species occurring in the Mediterranean: Isoëtes sicula, which according to some authors should be included as a variety in I. histrix, and the recently described I. todaroana, whose affinity with other taxa is currently unknown. Two additional species (I. duriei, I. velata) were also included in the analysis. The megaspores were studied using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and chemical treatment. In all species, the megaspore surface is cove…
Large Area Deposition by Radio Frequency Sputtering of Gd0.1Ce0.9O1.95 Buffer Layers in Solid Oxide Fuel Cells: Structural, Morphological and Electro…
2021
We investigate the influence of position, under large circular sputtering targets, on the final electrochemical performance of 35 mm diameter button solid oxide fuel cells with sputter-deposited Gadolinium doped Ceria barrier layers, positioned in order to almost cover the entirety of the area associated with a 120 × 80 mm2 industrial cell. We compare the results obtained via structural and morphological analysis to the Electrochemical Impedance Spectroscopy (EIS) measurements performed on the button cells, disentangling the role of different parameters. The Atomic Force Microscopy analysis makes it possible to observe a decrease in the roughness values from the peripheral to the central zo…
Electrosynthesis of Sn-Co nanowires in alumina membranes
2010
A fabrication process of amorphous nanowires of Sn-Co alloys, based on electrodeposition into anodic alumina membranes, is described. It is shown that nanowires of tin-cobalt alloys with different compositions can be produced by varying electrodeposition time and concentration ratio of salts dissolved into the electrolytic bath. Importance of the chelating agent to produce amorphous Sn-Co alloys has also been addressed. Electrodepositions were carried out potentiostatically at -1 V versus Saturated Calomel Electrode and 60 degrees C for times ranging from 10 to 90 minutes; the atomic fraction of Co2+ in the aqueous electrolyte (Co2+/(Co2+ + Sn2+)) was varied from 0.33 to 0.67. Nanowires asp…
Characterization of prehispanic cosmetics found in a burial of the ancient city of Teotihuacan (Mexico)
2012
The present paper reports the chemical data obtained on samples of pigmenting materials contained in 31 miniature vessels found in a burial found in Teopancazco, a multiethnic neighborhood center located in the southeastern sector of the archaeological site of Teotihuacan (Central Mexico) and the analytical protocol established for the complete characterization of these archaeological materials. For this purpose a multi-technique approach based on the combination of several non destructive and micro-destructive instrumental techniques, namely, light microscopy (LM), scanning electron microscopy-X-ray micro-analysis (SEMe EDX), transmission electron microscopy (TEM), voltammetry of micropart…
Nanovector formation by functionalization of TRAIL ligand on single-walled carbon nanotube: Experimental and theoretical evidences
2015
Équipe 104 : Nanomatériaux; International audience; The synthesis and the characterization of a novel nanovector based on oxidized single-walled carbon nanotubes (SWCNT) functionalized with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) via noncovalent 1-pyrenebutanoic acid N-hydrosuccinimid ester (PSE) is described. Experimental noncovalent functionalized SWCNT by PSE are compared to full DFT theoretical predictions. For this, several experimental techniques are gathered to prove the well functionalization of oxidized SWCNT by pi-pi stacking such as micro Raman and XPS spectroscopy analysis coupled to full-DFT calculations. Scanning transmission electron microscopy (STEM) …
Characterization of spatial porosity and mineral distribution of crystalline rock using X-ray micro computed tomography, C-14-PMMA autoradiography an…
2019
The spatial porosity and mineral distribution of geological materials strongly affects transport processes in them. X-ray micro computed tomography (X-mu CT) has proven to be a powerful tool for characterizing the spatial mineral distribution of geological samples in 3-D. However, limitations in resolution prevent an accurate characterization of pore space especially for tight crystalline rock samples and 2-D methods such as C-14-polymethylmethacrylate (C-14-PMMA) autoradiography and scanning electron microscopy (SEM) are needed. The spatial porosity and mineral distributions of tight crystalline rock samples from Aspo, Sweden, and Olkiluoto, Finland, were studied here. The X-mu CT were use…
Modified Graphene Sheet Stacks for Hydrogen Binding
2017
Results are partially obtained using infrastructure of Lithuanian Energy Institute with support of COST Action MP1103 “Nanostructured materials for solid-state hydrogen storage”. Latvian National Research program IMIS2 is greatly acknowledged for financial support