Search results for "transition"

Atomic layer deposition of polyimide thin films

2007

The atomic layer deposition (ALD) of different polyimide thin films has been studied. We have demonstrated self-limiting ALD deposition of PMDA–DAH, PMDA–EDA, PMDA–ODA and PMDA–PDA thin films at 160 °C. The maximum deposition rate of 5.8 A cycle−1 was obtained for the PMDA–DAH process. Although the deposition rate was high at 160 °C, a sudden decrease was observed when the temperature was increased. Regardless of the process studied, no film growth was obtained at 200 °C or above. Deposited polyimide films were analysed by FTIR, AFM and TOF-ERDA. According to the FTIR measurements, imide bonds were formed already in as-deposited films indicating polyimide formation without any additional th…

Metal-support and preparation influence on the structural and electronic properties of gold catalysts

2006

Abstract Nanostructured gold catalysts supported on CeO2 and SiO2 were prepared by the deposition–precipitation (DP) and the solvated metal atom dispersion (SMAD) techniques. The structural and electronic properties of the catalysts were investigated by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). Gold was found as small metal nanoparticles (cluster size ∼2 nm) in the SMAD-prepared samples and in ionic state in the DP catalysts. The catalytic activity of the samples was tested in the reaction of low temperature CO oxidation. Gold nanosized particles in a pure metallic state exhibited a worse catalytic performance, both on ceria and…

Oscillatory Changes of the Heterogeneous Reactive Layer Detected with the Motional Resistance during the Galvanostatic Deposition of Copper in Sulfur…

2015

Metallic copper was galvanostatically deposited on quartz|gold resonant electrodes by applying a constant current in a 0.5 M CuSO4/0.1 M H2SO4 aqueous solution. Galvanostatic copper deposition is one of the best methodologies to calibrate the electrochemical quartz crystal microbalances (EQCM), a gravimetric sensor to evaluate changes in mass during the electrochemical reactions through the Sauerbrey equation. The simultaneous measurement of mass, current density, and motional resistance by an EQCM with motional resistance monitoring allows us to characterize the processes occurring on the electrode surface and at the interfacial regions with unprecedented detail. During the galvanostatic c…

Conservative management of T1G3 transitional cell carcinoma of the bladder. Risk factor analysis in 165 selected patients

2003

INTRODUCTION AND OBJECTIVE: The management of TlG3 transitional cell carcinoma of the bladder (TCCB), is still controversial. Some Authors support an immediate radical cystectomy. BCG is considered the treatment of choice. Limited encouraging experiences are reported with intravesical chemotherapy. Objectives; Evaluating a selected population of 165 patients with TlG3 TCCB, in absence of Tis, treated conservatively with TUR plus adjuvant intravesical therapy. METHODS: Between January 1976 and December 1999, 165 patients with TlG3 bladder tumors were treated by TUR plus adjuvant intravesical therapy. Patients with previuos T1G3, Tis, more than 3 tumors or greater than 3 em were excluded. A s…

Quand le sport (dés)oriente les parcours des jeunes

2020

Référence interne : 20013; Axé sur la transition lycée-enseignement supérieur, ce rapport souligne la diversité des parcours vécus par des bacheliers et notamment des bacheliers professionnels dans le secondaire, en montrant leurs rapports pluriels aux études. Il étudie tout particulièrement comment des expériences et investissements sportifs peuvent impacter les orientations des jeunes, voire leur donner un tour inattendu, à l'image des bacheliers professionnels en STAPS ou des jeunes filles en filière masculine. L’expérience en lycée professionnel peut être perçue par certains comme une possibilité d'apprendre un métier ou d’obtenir le baccalauréat, d'autres la vivent comme une fermeture …

Bader’s topological analysis of the electron density in the pressure-induced phase transitions/amorphization in α-quartz from the catastrophe theory …

2013

In this work, the Bader's topological analysis of the electron density, coupled with Thom's catastrophe theory, was used to characterize the pressure-induced transformations in α-quartz. In particular, ab initio calculations of the α-quartz structures in the range 0-105 Gpa have been performed at the HF/DFT exchange-correlation terms level, using Hamiltonians based on a WC1LYP hybrid scheme. The electron densities calculated throughout the ab initio wave functions have been analysed by means of the Bader's theory, seeking for some catastrophic mechanism in the sense of Thom's theory. The analysis mainly showed that there is a typical fold catastrophe feature involving an O-O interaction at …

A Bader’s topological approach for the investigation of the high pressure stability field of the Mg-perovskite phase

2014

The pressure-induced ringwoodite to Mg-perovskite and periclase post-spinel phase transition: a Bader’s topological analysis of the ab initio electro…

2011

In order to characterize the pressure-induced decomposition of ringwoodite (c-Mg2SiO4), the topological analysis of the electron density q(r), based upon the theory of atoms in molecules (AIM) developed by Bader in the framework of the catastrophe theory, has been performed. Calculations have been carried out by means of the ab initio CRYSTAL09 code at the HF/DFT level, using Hamiltonians based on the Becke- LYP scheme containing hybrid Hartree– Fock/density functional exchange–correlation terms. The equation of state at 0 K has been constructed for the three phases involved in the post-spinel phase transition (ringwoodite -> Mg-perovskite + periclase) occurring at the transition zone–lower…

Justicia transicional: conceptos clave y aspectos normativos

2018

This paper is an exposition about the key concepts of transitional justice. We will introduce briefly its four basic measures (penal responsibility, truth seeking, victim reparations and nonrepetition guarantees). After that, we will analyse some of the normative aspects and dilemmas that these measures involve. These questions include: opposite exigencies (for example, between truth and justice); problems related with the application of universal abstract norms to particular contexts; the complex balance between truth, memory and reconciliation; a disquisition about the concept of victim and the concept of perpetrator; and a reflection concerning the future of transitional justice.

Accretion of arc-oceanic lithospheric mantle in the Mediterranean: Evidence from extremely high-Mg olivines and Cr-rich spinel inclusions in lamproit…

2007

Abstract Si-rich Mediterranean type lamproites (48–56 wt.% SiO2) are olivine-phyric, mantle-derived volcanics, in which both phenocrystic and xenocrystic olivine are present. Here we demonstrate the phenocrystic origin of the most extremely NiO–MgO enriched olivine in lamproites with Mg# up to 0.95, that host Cr-rich (Cr# around 0.95) spinels. Our comprehensive study of olivine–spinel pairs from Mediterranean lamproites enables us to constrain the extent of depletion of their mantle source. Olivine–spinel pairs from primitive Mediterranean lamproites plot in the most refractory part of the olivine–spinel mantle array diagram, showing even more refractory character than mineral pairs from bo…