Distribution of 1.68 eV emission from diamond films

Free-standing polycrystalline chemical vapor deposition diamond films grown on a silicon wafer, with electrical behavior similar to values currently mentioned in the literature, present microheterogeneity. A detailed analysis by micro Raman shows how the diamond and nondiamond phases are distributed within the film and also the distribution of the silicon related luminescence. This luminescence is discussed in terms of two emitting centers close in energy. Absolute intensity of the diamond peak is not correlated with the good quality of the film as assessed by the Raman linewidth and ratio of this line to the nondiamond Raman line

Structural and optical properties of Zn0.9 Mn0.1 O/ZnO core-shell nanowires designed by pulsed laser deposition

Partilhar documento na coleção da comunidade Laboratório Associado I3NCore-shell ZnO/ZnMnO nanowires on a-Al2O3 and GaN (buffer layer)/Si (111) substrates were fabricated by pulsed laser deposition using a Au catalyst. Two ZnO targets with a Mn content of 10% were sintered at 1150 and 550 °C in order to achieve the domination in them of paramagnetic MnO2 and ferromagnetic Mn2O3 phases, respectively. Cluster mechanism of laser ablation as a source of possible incorporation of secondary phases to the wire shell is discussed. Raman spectroscopy under excitation by an Ar+ laser revealed a broad peak related to the Mn-induced disorder and a redshift in the A1-LO phonon. Resonant Raman measurements revealed an increase in the multiphonon scattering caused by disorder in ZnO upon doping by Mn. Besides the UV emission, a vibronic green emission band assisted by a ∼ 71 meV LO phonon is also observed in the photoluminescence spectra. Core-shell structures with smooth shells show a high exciton to green band intensity ratio ( ∼ 10) even at room temperature. © 2009 American Institute of PhysicsSANDiE Network of Excellence of the EUFCT-PTDC/FIS/72843/200

Tin determination in fistula seals from Conimbriga and Augusta Emerita

info:eu-repo/semantics/publishedVersio

Preparation of hybrid organic-inorganic materials based on a di-ureasil matrix doped with lithium bis(trifluoromethanesulfonyl)imide

In this presentation we describe the preparation of solvent-free solid polymer electrolytes (SPEs) by the sol-gel route with the incorporation of controlled quantities of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) into the host matrix. The host framework of these xerogels, designated as di-ureasils and represented by d-U(900), contains oxyethylene oligomers with about 15 repeat units bonded at each end to a siliceous backbone through urea bridging links. Electrolytes were characterized by ionic conductivity measurements, cyclic voltammetry at a gold microelectrode and thermal analysis. The results obtained reveal that these hybrid materials are completely amorphous and exhibit appropriate electrochemical characteristics for a variety of applications.Fundação para a Ciência e a Tecnologia - POCI/QUI/59856/2004; POCTI/3/686; SFRH/BD/22707/2005

Low-intensity resistance exercise does not affect cardiac autonomic modulation in patients with peripheral artery disease

OBJECTIVE: To analyze the effect of a single bout of resistance exercise on cardiac autonomic modulation in patients with peripheral artery disease. METHODS: Fifteen patients with peripheral artery disease (age: 58.3±4.0 years) underwent the following sessions in a random order: resistance exercise (three sets of 10 repetitions of the six resistance exercises with a workload of 5-7 in the OMNI-RES scale) and control (similar to the resistance session; however, the resistance exercises were performed with no load). The frequency domain (low frequency, high frequency and sympathovagal balance) and symbolic analysis (0V, 1V and 2V patterns) of heart rate variability were obtained before and until one hour after the interventions. RESULTS: After the resistance exercise and control sessions, similar increases were observed in the consecutive heartbeat intervals (control: 720.8±28.6 vs. 790.9±34.4 ms; resistance exercise: 712.9±30.1 vs. 756.8±37.9 ms;