Search results for "Metals"
showing 10 items of 2013 documents
Solid proton conductors as room-temperature gas sensors
1993
Ammonia-exchanged ceramic samples of beta alumina have been obtained from plasma-dispersed powders. The ionic conductivity is slightly affected by ion exchange, but the surface conductivity for the amonia-exchanged sample drastically changes in the presence of the water and ammonia vapours. The ammonia-doped xerogel of antimonic acid hydrate in the form of a thick film has been tested as a potentiometric ammonia sensor.
Impact of point defects on the elastic properties of BaZrO3: Comprehensive insight from experiments and ab initio calculations
2018
Abstract Acceptor doped BaZrO3 is the prototype of proton conducting perovskites which are of strong interest as electrolytes for intermediate temperature fuel cells. Elastic properties of both dry and hydrated Y-doped BaZrO3 (1.5–17 mol% Y) were determined using ultrasound time of flight (TOF) measurements, and complemented by ab initio calculations which allow for an analysis of the different contributions. The experimental and theoretical findings are consistent and reveal a strong decrease of the Young's, shear and bulk moduli upon increasing dopant concentration. This decrease is attributed to a combined effect of (i) macroscopic lattice chemical expansion mainly caused by differing io…
Heat transfer in semi-transparent materials during laser interaction
2004
Abstract A model of energy exchange, based on the finite element method is specially developed to determine the thermal field for semi-transparent polymers irradiated by laser. Our model, which uses the finite element method, allows to define the laser and specific structure characteristics in terms of density of power, speed and shape of the spotlight, material coefficient absorption, etc. The model has been experimentally validated by measuring the thermal response induced by the laser source. The experimental part of the study has been performed using a semiconductor laser diode source and an infrared thermography camera.
Slow relaxation of the magnetization, reversible solvent exchange and luminescence in 2D anilato-based frameworks.
2020
A series of multifunctional 2D frameworks prepared with Dy(iii) and the bromanilato ligand, formulated as: [Dy2(C6O4Br2)3(G)n]·nG with G = H2O, dimethylformamide (dmf) and dimethylsulfoxide (dmso), can exchange the coordinated and non-coordinated solvent molecules (G) in a reversible way. These multifunctional frameworks show field induced slow relaxation of the magnetization and luminescence that can be easily and reversibly modified by solvent exchange.
Stronger host-guest binding does not necessarily give brighter particles: a case study on polymeric AIEE-tunable and size-tunable supraspheres.
2018
Supraspheres were prepared from a pillar[5]arene-based linear polymer (the host) and several multitopic guests. According to host-guest binding studies in nanosystems, the optical and structural properties (fluorescence capability, density, and particle size) of the nanoparticles were correlated not with the host-guest binding affinities, but with the relative fluorescence quantum yield.
Liquid phase exfoliation of carbonate-intercalated layered double hydroxides.
2019
Direct exfoliation of a carbonate layered double hydroxide (LDH) has been achieved by using a novel horn-probe sonic tip, avoiding the development of time-consuming anion-exchange reactions. The most suitable solvents were chosen based on the Hildebrand solubility parameters and the thickness of the exfoliated nanosheets confirmed unambiguously the successful delamination.
Towards the Loewenstein limit (Si/Al = 1) in thermally stable mesoporous aluminosilicates
1999
The use of complexing agents to generate polynuclear precursor species containing both Al and Si allows the synthesis of thermally stable mesoporous aluminosilicates including solely tetrahedrally coordinated aluminium, in which the Si/Al ratio can be modulated down to a minimum Si/Al value of 1.06(4). Cabrera Medina, Saul, Saul.Cabrera@uv.es ; El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Latorre Saborit, Julio, Julio.Latorre@uv.es ; Beltran Porter, Aurelio, Aurelio.Beltran@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es
Metal enhanced fluorescence in rare earth doped plasmonic core–shell nanoparticles
2013
International audience; We theoretically and numerically investigate metal enhanced fluorescence of plasmonic core–shell nanoparticles doped with rare earth (RE) ions. Particle shape and size are engineered to maximize the average enhancement factor (AEF) of the overall doped shell. We show that the highest enhancement (11 in the visible and 7 in the near-infrared) is achieved by tuning either the dipolar or the quadrupolar particle resonance to the rare earth ion's excitation wavelength. Additionally, the calculated AEFs are compared to experimental data reported in the literature, obtained in similar conditions (plasmon mediated enhancement) or when a metal–RE energy transfer mechanism is…
Hybrid organic-inorganic light-emitting diodes.
2011
The demonstration of colour tunability and high efficiency has brought organic light-emitting diodes (OLEDs) into the displays and lighting market. However, high production costs due to expensive deposition techniques and the use of reactive materials still limit their market entry, highlighting the need for novel concepts. This has driven the research towards the integration of both organic and inorganic materials into devices that benefit from their respective peculiar properties. The most representative example of this tendency is the application of metal oxides in organic optoelectronics. Metal oxides combine properties such as high transparency, good electrical conductivities, tuneable…
Structural analysis of W3O/WO3 and TiO/TiO2 periodic multilayer thin films sputter deposited by the reactive gas pulsing process
2012
International audience; DC reactive sputtering was used to deposit titanium and tungsten-based metal/oxide periodic nanometric multilayers using pure metallic targets and Ar + O-2 gas mixture as reactive atmosphere. The innovative technique namely, the reactive gas pulsing process allows switching between the metal and oxide to prepare a periodic multilayered structure with various metalloid concentrations and nanometric dimensions. The same pulsing period was used for each deposition to produce metal-oxide periodic alternations close to 10 nm. Structure, crystallinity and chemical composition of these films were systematically investigated by Raman spectroscopy, X-ray diffraction and Energ…