Preparo e caracterização de compósitos polímero/cerâmica com potencial aplicação como sensor multifuncional

Pós-graduação em Química - IQ

Characterization and application of nanostructured films containing Au and TiO2 nanoparticles supported in bacterial cellulose

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Innovative low temperature plasma approach for deposition of alumina films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ferroelectric and dielectric characteristics of Bi3.25La0.75Ti3O12 thin films prepared by the polymeric precursor method

The ferroelectric properties and leakage current mechanisms of preferred oriented Bi3.25La0.75 Ti3O12 (BLT) thin films deposited on La0.5Sr0.5CoO3 (LSCO) by the polymeric precursor method were investigated. Atomic force microscopy indicates that the deposited films exhibit a dense microstructure with a rather smooth surface morphology. The improved ferroelectric and leakage current characteristics can be ascribed to the plate-like grains of the BLT films. © 2006 Trans Tech Publications, Switzerland.

Effect of Zn Sputtering Rate on the Morphological and Optical Properties of ZnO Films

Zinc oxide (ZnO) and aluminum-doped zinc oxide (ZnO:Al) thin films were deposited onto glass and silicon substrates by RF magnetron sputtering using a zinc-aluminum target. Both films were deposited at a growth rate of 12.5 nm/min to a thickness of around 750 nm. In the visible region, the films exhibit optical transmittances which are greater than 80%. The optical energy gap of ZnO films increased from 3.28 eV to 3.36 eV upon doping with Al. This increase is related to the increase in carrier density from 5.9 × 1018 cm-3 to 2.6 × 1019 cm-3. The RMS surface roughness of ZnO films grown on glass increased from 14 to 28 nm even with only 0.9% at Al content. XRD analysis revealed that the ZnO films are polycrystalline with preferential growth parallel to the (002) plane, which corresponds to the wurtzite structure of ZnO.

Magnetic properties of YBCO/LCMO superlattices with and without STO interlayers

Superlattices formed of two antagonic characteristics have been broadly studied in literature mainly in order to clarify the effects of proximity and interface interactions. Here, we present a study of superlattice introducing an insulator between each superconducting and ferromagnetic layer. The electrical insulator STO, YBCO and LCMO layer are deposited by PLD method. The samples with STO show more intergrowth surface morphology, which favors the application providing better contacts between the grains. The magnetic measurements indicated higher Tc values and high anisotropy for SLs with STO, which is dependent on the relative thickness of LCMO and YBCO.

Caracterização morfológica e cristalográfica da zircônia após desgaste com pedra diamantada e elaboração de um protocolo para tratamento térmico regenerativo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Classificação de potenciais unidades climáticas em Presidente Prudente-SP

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Citotoxicidade do ácido peracético: avaliação metabólica, estrutural e de morte em fibroblastos L929

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Floral anatomy of Bromeliaceae, with particular reference to the evolution of epigyny and septal nectaries in commelinid monocots

Floral anatomy is described in ten genera of Bromeliaceae, including three members of subfamily Bromelioideae, three Tillandsioideae, and four genera of the polyphyletic subfamily Pitcairnioideae (including Brocchinia, the putatively basal genus of Bromeliaceae). Bromeliaceae are probably unique in the order Poales in possessing septal nectaries and epigynous or semi-epigynous flowers. Evidence presented here from floral ontogeny, vasculature, and the relative positions of nectary and ovules indicates that there could have been one or more reversals to apparent hypogyny in Bromeliaceae, although this hypothesis requires a better-resolved phylogeny. Such evolutionary reversals probably evolved in response to specialist pollinators, and in conjunction with other aspects of floral morphology of Bromeliaceae, such as the petal appendages of some species. The ovary is initiated in an inferior position even in semi-epigynous or hypogynous species. The ovary of all so-called hypogynous Bromeliaceae is actually semi-inferior, because the septal nectary is infralocular; in these species the nectaries have a labyrinthine surface and many vascular bundles. Brocchinia differs from most other fully epigynous species in that each carpel is secretory at the apex and reproductive, rather than secretory, at the base.

Diversity and evolution of macrohabitat use, body size and morphology in a monophyletic group of Neotropical pitvipers (Bothrops)

The Neotropical pitviper genus Bothrops comprises about 40 species, which occur in all main ecosystems of cis-Andean South America. We explored the relationships of body size and form (tail length and stoutness) with macrohabitat use in 20 forms of Bothrops. Sen-ii-arboreal habits appeared only in forest forms. Semi-arboreals are significantly more slender and have longer tails than terrestrials; body size is not significantly different between terrestrials and semi-arboreals. Within Bothrops, independent contrasts for macrohabitat use were significantly correlated with contrasts of tail size (positively) and stoutness (negatively); thus, the more arboreal the species, the longer its tail and the more slender its body. Contrasts of adult body size seems to remain constant over the lower range of macrohabitat use, but to decrease in species of Bothrops which are more arboreal. Reconstructions of character states indicate that: (1) the ancestor of Bothrops was a small, stout, terrestrial species; (2) semi-arboreal habits appeared one to three times in the genus; (3) a decrease in stoutness and an increase in tail length occurred along with an increase in arboreality in some clades. Although macrohabitat use seems to be important in determining body form in Bothrops, our results also indicate that tail size, stoutness and body size may also be affected by selective agents other than macrohabitat use. The selective agents responsible for the shifts in macrohabitat use in Bothrops are still uncertain, although they may have included prey availability and/or predation pressure. The plasticity of macrohabitat use, morphology and body size described in this study may have been key features that facilitated the highly successful ecological diversification of Bothrops in South America.

Bond strength and morphology of resin materials applied to the occlusal surface of primary molars

International Journal of Paediatric Dentistry 2012; 22: 435441 Background. Hydrophilic adhesives may be used as pit and fissure sealants (sealants), but there is concern about the ability of self-etching adhesives to bond sealants to enamel. Aim. To study the bond strength (BS) and morphology of adhesive systems used as sealants. Design. OptiBond FL, OptiBond All-in-One, combined OptiBond All-in-One + OptiBond FL adhesive, and Fluroshield were applied to the occlusal surfaces of 16 primary molars (n = 4). Teeth were stored in distilled water (24 h at 37 degrees C) and sectioned through the interface to obtain sticks (0.8 mm2) tested under a tensile load (0.5 mm/min). Failure modes were observed. Data were analysed by ANOVA and Tukeys tests (a = 5%). The morphology of 12 primary molars was examined in terms of the etching pattern and resin reproduction. Results. Differences in the BS were found (P = 0.001), with OptiBond FL showing the highest (36.84 +/- 5.7 MPa), Fluroshield (24.26 +/- 2.13 MPa) and OptiBond All-in-One (17.12 +/- 4.97 MPa) similar, and OptiBond All-in-One + OptiBond FL adhesive the lowest (9.8 +/- 2.94 MPA). OptiBond FL showed the best results in terms of morphology. Conclusion. Under the conditions of this study, OptiBond FL was the best material to be used for sealing.

Evolution equation for short surface waves on water of finite depth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electrocatalysis of hydrogen evolution reaction on Pt electrode surface-modified by S-2 chemisorption

Kinetic studies of hydrogen evolution reaction (HER) at the surface of Pt in alkaline conditions, reported in this paper, show that electrocatalytic activity is enhanced after adsorption of S-2 ions. EIS and steady-state polarization curve data pointed to an undoubted improvement in performance with the Pt-S cathode that was attributed to higher adsorbed hydrogen coverage. Experimental findings suggested an increase in the electronic density of the modified surface sites that may strengthen the interaction between H2O and the adsorption site and, consequently, accelerates the Volmer step. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

SURFACE EFFECTS IN THE HYDROGEN EVOLUTION REACTION ON NI-ZN ALLOY ELECTRODES IN ALKALINE-SOLUTIONS

Hydrogen evolution reaction was studied on Ni-Zn (25% of Ni before leaching) in 1 M NaOH at 25 degrees C. These electrodes were characterized by very low Tafel slopes of 67 mV dec(-1). Other techniques used included potential and current pulse, potential relaxation in an open circuit, and ac impedance spectroscopy. Analysis of the experimental results led to the conclusion that hydrogen adsorption in the surface layers was responsible for the observed behavior. Influence of the oxidation of the electrode surface and the addition of poisons, thiourea and cyanides, were also studied. These processes inhibit the hydrogen absorption and restore ''normal'' Tafel slopes. Kinetic parameters of the hydrogen evolution reaction were determined.