Search results for "Valence"
showing 10 items of 2732 documents
The Effect of Ni Doping on the Performance and Electronic Structure of LSCF Cathodes Used for IT-SOFCs
2018
We investigated the effect of nickel doping on the electronic structure and performance of nanostructured La0.6Sr0.4Co0.2Fe0.8-0.03Ni0.03O3-delta prepared by the one-pot sol gel method. The commercial undoped La0.6Sr0.4Co0.2Fe0.8O3-delta (ISCF0.8) was used as reference. Moreover, for comparison, Ni (3 mol %) was deposited by wetness impregnation over the La0.6Sr0.4Co0.2Fe0.8O3-delta. We show by in situ X-ray absorption spectroscopy at 900 degrees C under air flow that nickel enters the B perovskite site of the material and favors the stabilization of the cobalt oxidation state, as evidenced by the delay in the decrease of the average Co valence with respect to undoped samples. Our results a…
How Hydrogen Bonds Affect Reactivity and Intervalence Charge Transfer in Ferrocenium‐Phenolate Radicals
2016
The ferrocenyl-phenol 2,4-di-tert-butyl-6-(ferrocenylcarbamoyl)phenol (H-1) forms intramolecular hydrogen bonds which are absent in its constitutional isomer 2,6-di-tert-butyl-4-(ferrocenylcarbamoyl)phenol (H-2). Their corresponding bases 1– and 2– show intra- and intermolecular NH···O hydrogen bonds, respectively. The phenolate 1– is reversibly oxidized to 1·, whereas 2– only undergoes a quasi-reversible oxidation to 2·, which suggests a higher reactivity. The radical pools of 1· and 2· formed by the oxidation/deprotonation of H-1 and H-2 have been probed by (rapid-freeze) electron paramagnetic resonance (EPR) spectroscopy and by spin-trapping techniques to elucidate the types of radicals …
“Symptoms associated with environmental factors” (SAEF) – Towards a paradigm shift regarding “idiopathic environmental intolerance” and related pheno…
2020
Health conditions characterized by symptoms associated with chemical, physical and biological environmental factors unrelated to objectifiable pathophysiological mechanisms are often labelled by the general term “idiopathic environmental intolerances”. More specific, exposure-related terms are also used, e.g. “multiple chemical sensitivities”, “electromagnetic hypersensitivity” and “candidiasis hypersensitivity”. The prevalence of the conditions varies from a few up to more than 50%, depending on definitions and populations. Based on evolving knowledge within this field, we provide arguments for a paradigm shift from terms focusing on exposure and intolerance/(hyper-)sensitivity towards a t…
‘Stars’ or ‘professionals’: the imagined vocation and exclusive knowledge of translators in Israel
2010
Amb l’examen de la professionalització suspesa de l’ocupació traductora a Israel, aquest article estudia dos tipus de discursos d’autopresentació i estratègies d’estatus: d’una banda, els dels traductors literaris, i de l’altra, els dels traductors tècnics, subtituladors i traductors literaris que no pertanyen a l’elit. L’anàlisi del primer grup es fonamenta en diversos centenars d’articles retrat i altres reportatges en els mitjans de comunicació, que situen en primer pla 23 traductors reconeguts, mentre que la del segon grup es basa en resultats provisionals d’entrevistes obertes amb 22 treballadors de la traducció no pertanyents a l’elit (seleccionats a partir d’una mostra més àmplia reu…
Need for liver evaluation in polycystic ovary syndrome
2007
Medicine is changing and requires a more in-depth knowledge also in fields that were previously considered completely different and dedicated to other specialists. A good example of this general trend is the paper by Cerda et al. [1] that shows a high prevalence of nonalcoholic fatty liver disease (NAFLD) in women with Polycystic Ovary Syndrome (PCOS). The authors studied 41 young women with PCOS and found that 17 patients (41%) had NAFLD. In addition, 7 patients with NAFLD had increased aminotransferase levels raising the possibility of a transition to nonalcoholic steatohepatitis (NASH). Other reports have shown similar data recently [2–5]. It is time therefore that doctors caring for pat…
On Finite Satisfiability of Two-Variable First-Order Logic with Equivalence Relations
2009
We show that every finitely satisfiable two-variable first-order formula with two equivalence relations has a model of size at most triply exponential with respect to its length. Thus the finite satisfiability problem for two-variable logic over the class of structures with two equivalence relations is decidable in nondeterministic triply exponential time. We also show that replacing one of the equivalence relations in the considered class of structures by a relation which is only required to be transitive leads to undecidability. This sharpens the earlier result that two-variable logic is undecidable over the class of structures with two transitive relations.
Combining Inter-Subject Modeling with a Subject-Based Data Transformation to Improve Affect Recognition from EEG Signals
2019
Existing correlations between features extracted from Electroencephalography (EEG) signals and emotional aspects have motivated the development of a diversity of EEG-based affect detection methods. Both intra-subject and inter-subject approaches have been used in this context. Intra-subject approaches generally suffer from the small sample problem, and require the collection of exhaustive data for each new user before the detection system is usable. On the contrary, inter-subject models do not account for the personality and physiological influence of how the individual is feeling and expressing emotions. In this paper, we analyze both modeling approaches, using three public repositories. T…
57Co emission studies of cupric oxide
1990
Results on the incorporation, valence and spin states of Fe(Co) in CuO (with reference to similar studies on high temperature superconductors) and coupling of the Fe(Co) moment to the Cu magnetism in CuO are presented. Freshly prepared57Co: CuO shows two quadrupole doublets D1 and D2 withQ.S. of 2.49 and 1.52,I.S. of 0.35 and 0.70 mm/s and relative abundance of 74% and 26%, respectively at room temperature, the abundance being dependent on time in a sample exposed to ambient conditions and reaching 38 to 62% fifteen months after preparation. Below,TN=2251K, a typical combined magnetic-quadrupole interaction pattern is observed with a single saturation magnetic hfs of 25.6 T, central shift o…
Mössbauer Study of Lanthanum–Strontium Ferromanganite Oxides
2004
The La0.88Sr0.2Mn(1−y)Fey0(3±δ, i (LSMF with y = 0, 0.2, 0.5, 0.8, 1) compounds are prospective cathode materials for advanced solid oxide fuel cells (SOFC) application operating at 700° C. Usual analysis methods like thermogravimetric analysis or redox titration enable to determine the average oxidation state of both manganese and iron cations. The comparative role of iron and manganese in B-site was evaluated by 57Fe Mossbauer spectroscopy. Spectra revealed that the complete substitution of iron for manganese induces the formation of Fe5+ for the compound with y = 1. However, no tetravalent iron cation was observed in air for the LSMF compounds with y = 0.2, 0.5 and 0.8. This means that o…
Charge radii and neutron correlations in helium halo Nuclei
2011
Within the complex-energy configuration interaction framework, we study correlations of valence neutrons to explain the behavior of charge radii in the neutron halo nuclei $^{6,8}$He. We find that the experimentally observed decrease of the charge radius between $^6$He and $^8$He is caused by a subtle interplay between three effects: dineutron correlations, a spin-orbit contribution to the charge radius, and a core swelling effect. We demonstrate that two-neutron angular correlations in the $2^+_1$ resonance of $^6$He differ markedly from the ground-state correlations in $^{6,8}$He.