Search results for "P25"
showing 10 items of 73 documents
Enhanced Electrochemical Properties of Na0.67MnO2 Cathode for Na-Ion Batteries Prepared with Novel Tetrabutylammonium Alginate Binder
2022
This research was funded by the State Education Development Agency, the Republic of Latvia, grant number 1.1.1.2/VIAA/1/16/166, "Advanced Materials for Sodium-Ion Batteries". Institute of Solid-State Physics, University of Latvia as the Centre of Excellence has received funding from the European Union's Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.
Electrolyte-driven electrochemical amplification by poly(thienylacetylene) encapsulated within Zeolite Y
2006
Electrochemical oxidation and reduction of poly(thienylacetylene) encapsulated inside zeolite Y (PTA@Y) exhibit with large anodic and cathodic doping currents with a significant reversibility. Thienyl groups lower the redox potential of polyacetylene chain whereas encapsulation stabilizes the resulting charged radical species blocking undesired post electron-transfer cross-link reactions. Size-exclusion effects associated produces an electrolyte-dependent amplification of currents recorded at PTA@Y-modified electrodes for electrochemical processes involving selected substrates in solution, namely, dinitrobiphenyl and benzidine. Keywords: Poly(thienylacetylene), Zeolite Y, Electrochemistry, …
Electrocatalysis of the oxidation of methylenedioxyamphetamines at electrodes modified with cerium-doped zirconias
2004
The catalytic effect of monoclinic and tetragonal cerium-doped zirconias (m-CexZr1−xO2 and t-CexZr1−xO2, 0<x<0.10, respectively), prepared from gel precursors, on the oxidation of methylenedioxyamphetamine (MDA) and methylenedioxymetamphetamine (MDMA) at pH 7.0 has been studied. Upon attachment of synthetic specimens to polymer film electrodes, an oxidation peak near to +1.05 V vs AgCl/Ag appears that is unaffected by chloride ions and common interfering compounds, namely, dopamine, norepinephrine and ascorbic acid. The catalytic effect appears to be strongly influenced by crystallinity of specimens and coordination of cerium, increasing from the amorphous starting material to t-CexZr1−xO2 …
Electrochemistry nanometric patterning of MOF particles: Anisotropic metal electrodeposition in Cu/MOF
2006
Abstract Electrodeposition of copper from Cu/MOF immersed into acetate buffer produces a quasi-periodic series of 10–20 nm sized laminae sandwiched within the pristine MOF lattice as monitored by voltammetry of microparticles/atomic force microscopy. This anisotropic patterning can be qualitatively described in terms of a highly orientation-dependent diffusion of electrons and charge-balancing electrolyte counterions in the MOF network.
Mass/charge balance as a tool to estimate dimensional change in polypyrrole-based actuators
2006
The deconvolution of the voltammograms of polypyrrole electrochemistry has proved to be possible through the electrochemical quartz crystal microbalance data using the F(dm/dQ) function. This deconvolution allows the evolution of the thickness of the polypyrrole films during their redox processes to be estimated and therefore, the mechanical contraction/decontraction of this polymer as a function of the ionic exchange processes can be evaluated. Keywords: Polypyrrole, EQCM, Thickness change
Automatic regrouping of strata in the goodness-of-fit chi-square test
2019
Pearson’s chi-square test is widely employed in social and health sciences to analyze categorical data and contingency tables. For the test to be valid, the sample size must be large enough to provide a minimum number of expected elements per category. This paper develops functions for regrouping strata automatically no matter where they are located, thus enabling the goodness-of-fit test to be performed within an iterative procedure. The functions are written in Excel VBA (Visual Basic for Applications) and in Mathematica. The usefulness and performance of these functions is illustrated by means of a simulation study and the application to different datasets. Finally, the iterative use of …
Azolium and acetate ions in DMF: Formation of free N-heterocyclic carbene. A voltammetric analysis
2016
In order to reveal the possible formation of free N-heterocyclic carbene (NHC) in DMF-azolium and acetate solutions, the proton exchange equilibrium between azolium cations and CH3COO− was investigated (by cyclic voltammetry) by adding CH3COOH or tetrabutylammonium acetate to DMF solutions of imidazolium or thiazolium salts of different acidity.The voltammetric analysis confirms that the deprotonation of the azolium cation by CH3COO− (with the formation of free NHC) is significant in the case of the more acidic thiazolium cations, while it is not effective with the less acidic imidazolium ones.Accordingly, the NHC-catalyzed benzoin condensation was carried out in DMF solutions of azolium sa…
How alternative food networks work in a metropolitan area? An analysis of Solidarity Purchase Groups in Northern Italy
2019
AbstractOur paper focuses on Solidarity Purchase Group (SPG) participants located in a highly urbanized area, with the aim to investigate the main motivations underlining their participation in a SPG and provide a characterization of them. To this end, we carried out a survey of 795 participants involved in 125 SPGs in the metropolitan area of Milan (Italy). Taking advantage of a questionnaire with 39 questions, we run a factor analysis and a two-step cluster analysis to identify different profiles of SPG participants. Our results show that the system of values animating metropolitan SPG practitioners does not fully conform to that traditionally attributed to an alternative food network (AF…
Urban segregation and unemployment: A case study of the urban area of Marseille – Aix-en-Provence (France)
2018
International audience; In this paper, we study the effects of the spatial organization of the urban area of Marseille – Aix-en-Provence on unemployment there. More specifically, differences in the characteristics of the residential population induce urban stratification with the result that urban structure may affect the probability of employment. In order to evaluate the effects of spatial structure on unemployment, we implement a spatial probit model to reveal the employment probabilities of young adults still living with their parents. Our results support the hypothesis that living in or near a deprived neighborhood decreases the probability of employment.
Novel procedure for the template synthesis of metal nanostructures
2008
In this work we describe a novel method for the fabrication of a regular and uniform array of Cu nanowires into anodic alumina membranes. It is based on galvanic contact between the metal sputtered film covering the bottom of template and a less noble metal. The growth rate was estimated as function of the immersion time. Nanowires with aspect ratio from 12 to 286 were obtained by adjusting the deposition time. Copper nanowires were found to be polycrystalline with an average crystalline size of about 40 nm. This procedure can be applied for the preparation of a wide range of metallic nanostructures and it can be easily scaled up for industrial processing. Keywords: Displacement deposition,…