Search results for "Metals"
showing 10 items of 2013 documents
Upconversion luminescence of a transparent glass ceramics with hexagonal Na(Gd,Lu)F4 nanocrystals
2017
Novel Er3+ doped transparent glass ceramics containing hexagonal Na(Gd,Lu)F4 nanocrystals were prepared from oxyfluoride glasses. The distribution of rare earth ions in the crystalline and glassy phase has been analyzed by X-ray diffraction and erbium luminescence decay kinetics measurement. A strong deviation of rare earth ion content in fluoride nanocrystals in comparison to the base glass has been observed. Preferential incorporation of Gd3+ over Lu3+ ions in the fluoride lattice leads to the stabilization of hexagonal Na(Gd,Lu)F4 structure and prevents the formation of cubic fluorite type solid solutions. A considerable enhancement of upconversion luminescence correlates with the format…
From human to artificial mouth, from basics to results
2009
Papier publié également dans : Proceedings en ligne de American Institute of Physics http://proceedings.aip.org/dbt/dbt.jsp?KEY=APCPCS&Volume=1137&Issue=1 (RN 2508; Sensory perception of the flavor release during the eating of a food piece is highly dependent upon mouth parameters. Major limitations have been reported during in vivo flavor release studies, such as marked intra- and inter-individual variability. To overcome these limitations, a chewing simulator has been developed to mimic the human mastication of food samples. The device faithfully reproduces most of the functions of the human mouth. The active cell comprises several mobile parts that can accurately reproduce shear and comp…
Bias and humidity effects on the ammonia sensing of perylene derivative/lutetium bisphthalocyanine MSDI heterojunctions
2016
International audience; In this paper, we prepared and studied sensors based on Molecular Semiconductor-Doped Insulator (MSDI) heterojunctions. These original devices are built with two stacked layers of molecular materials and exhibit very specific electrical and sensing properties. We studied the properties of a MSDI composed of the perylenetetracarboxylic dianhydride, PTCDA, or the fluorinated perylenebisimine derivative, C4F7-PTCDI, as n-type molecular material sublayers, and LuPc2 as a p-type semiconductor top layer. Their response to ammonia was compared to that of a resistor formed of only the top layer of the MSDI (LuPc2). Ammonia increases the current in the MSDIs whereas it causes…
The financial impact of Spanish pension reform: A quick estimate
2012
In this paper, we present a preliminary estimate of the financial impact of the recent reform of the Spanish pension system. After updating the projections of pension expenditure constructed in de la Fuente and Doménech (2010) for the period 2008-2060, we analyze the impact on this variable of raising the retirement age from 65 to 67 years, extending from 15 to 25 years the period over which wages are averaged to calculate the starting pension and increasing from 35 to 37 the number of contribution years required to obtain a 'full pension.' Conditional on a series of assumptions about the evolution of employment, productivity and demographics, our estimates suggest that these measures will …
Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates†
2011
During the mineralisation of metal carbonates MCO3 (M = Ca, Sr, Ba, Mn, Cd, Pb) liquid-like amorphous intermediates emerge. These intermediates that form via a liquid/liquid phase separation behave like a classical emulsion and are stabilized electrostatically. The occurrence of these intermediates is attributed to the formation of highly hydrated networks whose stability is mainly based on weak interactions and the variability of the metal-containing pre-critical clusters. Their existence and compositional freedom are evidenced by electrospray ionization mass spectrometry (ESI-MS). Liquid intermediates in non-classical crystallisation pathways seem to be more common than assumed.
Synergistic assembly of hyperbranched polyethylenimine and fatty acids leading to unusual supramolecular nanocapsules
2005
Self-assembly of hyperbranched polyethylenimine (PEI) and fatty acids leads to supramolecular inverted micellar structures that are able to irreversibly transfer water-soluble guest molecules into organic solvents. Perez Prieto, Julia, Julia.Perez@uv.es ; Stiriba, Salah Eddine, Salah.Stiriba@uv.es
Open-shell doublet character in a hexaazatrinaphthylene trianion complex
2015
Three-electron reduction of hexaazatrinaphthylene (HAN) with a magnesium(I) reagent leads to [(HAN){Mg(nacnac)}3] (1), containing a [HAN]3– ligand with a spin of S = ½. Ab initio calculations reveal that the [HAN]3– ligand in 1 has a groundstate wave function with multiconfigurational properties, and can be described as a triradicaloid species with a small amount of open-shell doublet character. peerReviewed
Ball-milling and AlB2 addition effects on the hydrogen sorption properties of the CaH2 + MgB2 system
2011
Abstract Among the borohydrides proposed for solid state hydrogen storage, Ca(BH 4 ) 2 is particularly interesting because of its favourable thermodynamics and relatively cheap price. Composite systems, where other species are present in addition to the borohydride, show some advantages in hydrogen sorption properties with respect to the borohydrides alone, despite a reduction of the theoretical storage capacity. We have investigated the milling time influence on the sorption properties of the CaH 2 + MgB 2 system from which Ca(BH 4 ) 2 and MgH 2 can be synthesized by hydrogen absorption process. Manometric and calorimetric measurements showed better kinetics for long time milled samples. …
The ferrimagnetic compounds CoM[M’(EDTA)]2⋅4H2O(M,M’=Co,Ni): Magnetic characterization of CoCo[Ni(EDTA)2]⋅4H2O
1990
Under the terms of the Creative Commons Attribution (CC BY) license to their work.
Guest exchange in dimeric capsules of a tetraurea calix[4]arene in the solid state
2007
A solid powder of hydrogen bonded dimers of a tetraurea calix[4]arene is able to exchange the encapsulated guest in contact with the vapor of a second guest. The molecules of a guest-free powder obtained from a polar solvent cannot rearrange in the solid phase to form new guest-filled capsules under these conditions.