Structural single crystal, thermal analysis and vibrational studies of the new rubidium phosphate tellurate Rb2HPO4RbH2PO4·Te(OH)6

AbstractThe determination of the crystalline structure of rubidium phosphate tellurate Rb2HPO4RbH2PO4·Te(OH)6 [RbPTe] is performed from single crystal X-ray diffraction data. The title compound crystallizes in the monoclinic system P2. The unit cell parameters are as follows: a=7.9500(7)Å, b=6.3085(6)Å, c=9.5008(9)Å, β=109.783(4)°, Z=2 and V=448.37(7)Å3.The crystal structure is constituted from isolated (PO43-) tetrahedra and (TeO66-) octahedra and two nonequivalent Rb+ cations. Material cohesion is built of O–H⋯O bondings and ionic interactions.The new synthesized material has been characterized using the differential scanning calorimetry (DSC), thermal analysis [differential thermogravimetric analysis (TG), thermodifference analysis (DTA) and the mass spectrometric analysis], FT-IR and Raman techniques.Thermal analysis, in the temperature range of 300–900K, confirms that the decomposition of this material took place in two steps. The differential scanning calorimetry analysis shows three endothermic peaks at 451, 463 and 481K.The existence of anionic groups in the structure has been confirmed by IR and Raman spectroscopy in the frequency ranges 3000–600cm−1 and 1300–50cm−1, respectively

LES DETERMINANTS CULTURELS ET ECONOMIQUES DE LA COMMUNICATION D'INFORMATIONS VOLONTAIRE SUR LE CAPITAL IMMATERIEL: CAS DES ENTREPRISES MULTINATIONALES

Depuis quelques années, les entreprises développent des stratégies de diffusion d'information sur le capital immatériel. La problématique de ce papier consiste à s'interroger sur les facteurs qui poussent les entreprises à diffuser des informations qui dépassent ou complètent les dispositions comptables portant sur le traitement des éléments immatériels. Des caractéristiques propres aux entreprises, issues de la théorie politico contractuelle, et des variables culturelles sont envisagées comme facteurs explicatifs de l'offre d'information sur le capital immatériel. Des analyses des équations structurelles sont réalisées à partir des données collectées dans les rapports annuels de l'année 2005 de 61 entreprises Multinationales. Les résultats montrent que les variables portant sur la performance, la structure de l'actif, la taille du cabinet d'audit et la multinationalisation permettant de prédire le comportement des entreprises multinationales sur l'information immatériel.Capital immatériel; diffusion d'information; théorie politico contractuelle; dimension culturelle

OFFRE VOLONTAIRE D'INFORMATIONS SUR LE CAPITAL INTELLECTUEL ET MARCHE FINANCIER

Malgré une controverse de longue date, les normes comptables et les états financiers correspondants semblent intrinsèquement incapables de prendre en compte les actifs intellectuels. Comme les investisseurs ne peuvent plus s'en remettre aux états financiers pour avoir une image complète d'une société, ils se heurtent à de nouveaux problèmes d'évaluation, ce qui touche à la façon dont ils prennent leurs décisions d'investissement. Le principe fondamental de ce travail de recherche est le suivant: la diffusion sur le marché d'une quantité suffisante et substantielle d'informations non financières sur le capital intellectuel permet d'améliorer l'exercice des droits de propriété. Des équations structurelles réalisées à partir des données collectées dans les rapports annuels de l'année 2005 de 71 entreprises multinationales montrent qu'il existe une relation positive entre l'offre volontaire d'informations sur le capital intellectuel et la valorisation boursière.Capital intellectuel, Offre volontaire d'informations, marché boursier

Etude du comportement tribologique d'un composite PTFE/Bronze/MoS2 en glissement sec et lubrifié

Les réponses en frottement et en usure d'un composite PTFE/Bronze/MoS2 utilisé dans les bagues de guidage de vérins hydrauliques sont analysées en conditions de glissement sec et lubrifié. Un tribomètre bille/plan a mouvement linéaire alterné est utilisé pour la caractérisation expérimentale du comportement tribologique du composite. Le passage du contact sec au contact lubrifié engendre une réduction importante du coefficient de frottement. Le coefficient de frottement présente une croissance rapide au-delà de 20. ; cycles en condition de glissement sec alors qu'il présente une croissance progressive dès le début de l'essai pour se stabiliser à partir de 20. ; cycles en condition de glissement lubrifié. La sévérité de l'usure est largement réduite avec la lubrification. Pour les deux conditions de glissement, le volume d'usure présente initialement une croissance progressive pour se stabiliser vers la fin de l'essai. En condition de glissement sec, un mécanisme d'usure initialement adhésif cède la place vers la fin de l'essai à un mécanisme abrasif suite à la production de particules et/ou aspérités dures dans le contact. En condition de glissement lubrifié, la présence de l'huile dans le contact empêche l'oxydation des particules de MoS2 en particules dures de MoO3, ce qui permet d'améliorer les réponses en frottement et en usure

Juvenile recurrent parotitis in a 4-year-old patient: a case report

Juvenile recurrent parotitis (JRP) is a rare disease. It is most commonly occurring between the ages of 3 and 5 years, that classically resolves at adolescence. It is characterized by recurrent non-suppurative parotitis, with several acute inflammatory episodes per year. The parotid´s swelling tends to be unilateral, but it can occur bilaterally, with a more predominant side. The aim of this work was to present a case report that highlights signs and symptoms of this unusual condition and to stress on the value of ultrasonography as an aid to diagnosis

Development and tribological characterisation of nanostructured Zn-Ni and Zn-Co coatings: a comparative study

International audienceZn-Ni and Zn-Co alloy coatings were electrodeposited on mild steel from sulphate-based baths. The morphology, microstructure, microhardness and tribological behaviours of the coatings have been studied and discussed. While the Zn-5wt-% Co layers presented a nanocrystalline simple nodular structure (45 ± 5 nm), the Zn-14wt-% Ni showed a particular structure called cauliflower morphology (30 ± 7 nm). The X-ray diffraction analysis showed that each of the electrodeposits was formed from zinc solid solution with a uniform zinc-cobalt intermetallic phase γ 2 (CoZn 13) for Zn-5wt-% Co alloy. However, a single γ-phase (intermetallic compound Ni 5 Zn 21) was presented for the Zn-14wt-% Ni alloys. The Zn-14wt-% Ni films were found to be harder and rougher than the Zn-5wt-% Co layers. Plastic deformation and oxide layers production were the main wear mechanisms for the investigated coatings. The Zn-14wt-% Ni coatings were found to have the best wear resistance due to their microhardness and particular structure. ARTICLE HISTOR

Redetermination of the crystal structure of β-zinc molybdate from single-crystal X-ray diffraction data

This is an open-access article distributed under the terms of the Creative Commons Attribution Licence.The crystal structure of the β-polymorph of ZnMoO4 was re-determined on the basis of single-crystal X-ray diffraction data. In comparison with previous powder X-ray diffraction studies [Katikaneani & Arunachalam (2005 ▸). Eur. J. Inorg. Chem. pp. 3080–3087; Cavalcante et al. (2013 ▸). Polyhedron, 54, 13–25], all atoms were refined with anisotropic displacement parameters, leading to a higher precision with respect to bond lengths and angles. β-ZnMoO4 adopts the wolframite structure type and is composed of distorted ZnO6 and MoO6 octa­hedra, both with point group symmetry 2. The distortion of the octa­hedra is reflected by variation of bond lengths and angles from 2.002 (3)–2.274 (4) Å, 80.63 (11)–108.8 (2)° for equatorial and 158.4 (2)– 162.81 (14)° for axial angles (ZnO6), and of 1.769 (3)–2.171 (3) Å, 73.39 (16)–104.7 (2), 150.8 (2)–164.89 (15)° (MoO6), respectively. In the crystal structure, the same type of MO6 octa­hedra share edges to built up zigzag chains extending parallel to [001]. The two types of chains are condensed by common vertices into a framework structure. The crystal structure can alternatively be described as derived from a distorted hexa­gonally closed packed arrangement of the O atoms, with Zn and Mo in half of the octa­hedral voids.We acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MAT2013–40950-R), Gobierno del Principado de Asturias (GRUPIN14–060) and ERDF.Peer Reviewe

A new hybrid iron fluoride bipyridine with mixed valence: Fe2F5(2,2'-bipyridine)2H2O

Hydrothermal synthesis of iron fluoride compound, Fe2F5(2,2'-bipyridine)2H2O, and its characterization by single crystal X-ray diffraction is reported. The compound is found to crystallize in the triclinic space group . The monohydrate fluoroferrate of bipyridine is built up from Fe4F10N8 tetrahedron connected by eight nitrogen atoms of four 2,2'-bipyridine molecules and separated by H2O molecules. The main feature of this atomic arrangement is the coexistence of two oxidation states of iron cations and hybrid class II with 0-D dimensionality. Thermal and IR spectral analysis have been carried out for the title compound to confirm the hematite compound as residual and the presence of organic molecule , respectively. Magnetic characterization does not reveal any ferromagnetic component in the range of magnetic field from -20 kOe to 20 kOe at room temperature

Novel phenoxazine-benzonitrile and phenothiazine-benzonitrile donor-acceptor molecules with thermally activated delayed fluorescence (TADF)

ABSTRACT: Four novel TADF emitters, containing phenothiazine and phenoxazine as electron-donors and benzonitrile derivatives as electron-acceptors were synthesized and fully characterized. Their photophysical (absorption and emission spectra, molar extinction coefficients, fluorescence quantum yields and lifetimes) and electrochemical properties (HOMO and LUMO energy levels) were measured, and drop-cast solid films of the four compounds were obtained to perform TADF studies. The obtained values for Delta E-ST indicate that these compounds are candidates for OLED applications.info:eu-repo/semantics/publishedVersio