Phenomenological Interpretation of Impedance/Capacitance Measurements on Organic Electronic Devices Under Illumination

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

Application of passive control to energy harvester efficiency using a nonideal portal frame structural support system

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

SeP hole injection layer for devices based on organic materials

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

An Experimental Study on the Effect of Temperature on Piezoelectric Sensors for Impedance-Based Structural Health Monitoring

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

Disorder induced interface states and their influence on the AI/Ge nanowires Schottky devices

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

Comportamento dinâmico não-linear em fenômenos de colheita de energia usando dispositivos baseados em materiais piezoelétricos em estruturas aporticadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sprayed films of europium complexes toward light conversion devices

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

Investigation of Bulk and DTMOS triple-gate devices under 60 MeV proton irradiation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Investigations on PVP/Y3BO6:Eu3+, a red Luminescent composite for lighting devices based on near UV-LEDs

This work deals with a red phosphor. Y3BO6:Eu3+, and its corresponding poly(N-vinylpyrrolidone) (PVP)/Y3BO6:Eu3+ luminescent composite film suitable for applications in the next generation of Hg-free lamps based on near ultraviolet (UV) light emitting diodes (LEDs). Well crystallized samples of Y3BO6 powders with the Eu3+ content up to 20 mol% were prepared by the Pechini method. After structural, morphological and optical characterization, the best doping rate of Eu3+ in the matrix was determined to be 15 mol%. This optimal powder, which is highly friable, was easily ground into fine particles and homogeneously dispersed into a PVP polymer solution to give rise to a polymer phosphor composite. Structural and optical features of the composite film have been studied and compared to those of a pristine PVP film and Y3BO6:Eu3+ powder. All the characterization (XRD, SAXS, luminescence...) proved that the red phosphor particles are well incorporated into the polymer composite film which exhibited the characteristic red emission of Eu3+ under UV light excitation. Furthermore, photostability of the polymer/phosphor composite film under UV-LED irradiation was evaluated from exposure to accelerated artificial photoageing at wavelengths above 300 nm.

Colheita de energia usando dispositivos baseados em materiais piezoelétrico

Recently, research on energy harvesting has increased substantially. Many researchers have concentrated their efforts to find the best configuration for these systems and to optimize their output power. In the process of energy harvesting, the electric energy is obtained by converting mechanics energy created by an environment vibration source by a transducer, for example, a thin piezoceramic film. That vibration source is, for example, a beam suffering some mechanic force able to generate a vibration in it, an oscillating beam is the best properly used example. Different mechanisms of electromechanical coupling have been developed to harvesting devices, and a particular interest has been given to the use of models that transform the mechanical vibration into electrical current using a piezoelectric element. In this paper we propose a model to energy harvesting from vibrations, from an oscillating beam, including non-linearities in the piezoelectric coupling and a non-ideal excitation in the material. From this model, it was developed a system to obtain some results about the harvested power by the material. It was demonstrated that the power captured was influenced by the effect of the nonlinearities of the piezoelectric coupling, modifying the system dynamic behavior

Síntese e caracterização de filmes finos de ferrita de bismuto dopados com cálcio visando aplicação em memórias de múltiplos estados

The increasing demand for electro-electronic devices, with high performance and multi-functional and the rapid advances of the nanotechnology require the development of new methods and techniques for the production and characterization of nanostructure materials and phenomenological models to describe/to predict some of its properties. The demand for multifunctionality requires, at least, new materials, that can integrate ferroelectric and magnetic properties of high technological interest. Inside of this context, multiferroics material can be considered suitable to integrate two or more physical properties of high technological interest. It can also provides new challenges in the processes of synthesis of new materials, and development of new devices with controlling and simulation of its physical properties and modeling. For this Calcium (Ca)-doped bismuth ferrite (BiFeO3) thin films prepared by using the polymeric precursor method (PPM) were characterized by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), polarization and piezoelectric measurements.In order to study the behavior and determine which are the most important parameters to achieve the optimal property to be applied to a multiferroic materials

Thickness-dependent piezoelectric behaviour and dielectric properties of lanthanum modified BiFeO3 thin films

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

Otimização do processamento de partículas lead-free para aplicação em compósitos polímero/cerâmica com propriedades piezoelétrica e fotoluminescente

Pós-graduação em Química - IQ

Morphology and adhesion on blood components in root surfaces treated by a piezoelectric ultrasonic: an in vitro study

The aim of this study was to evaluate the morphology and adhesion of blood components on root surfaces instrumented with piezoelectric ultrasonic Piezon Master Surgery. Methods 10 teeth were used in this study. The teeth had their proximal divided into four areas that received different treatments: Group 1: untreated control Group 2: scaling with manual instrument; Group 3: scaling with ultrasound; Group 4: Scaling with manual instruments and ultrasound. We obtained 20 samples, 10 of which were used to analyze the morphology and the other 10 were used for analysis of adhesion of blood components. The specimens were analyzed by scanning electron microscopy. Photomicrographs were analyzed by the scores of adhesion of blood components and the index of root morphology. The results were statistically by the Kruskall-Wallis and Mann-Whitney with a significance level of 95%. Results The morphological analysis showed that the Group 1 had a surface unchanged in relation to other groups (Group 1 X Group 2 = 0.0025; Group 1 X Group 3 = 0.0003; Group 1 X Group 4 = 0.0003) and Group 2 presented a smoother surface compared to Group 1 and groups instrumented with ultrasound (Group 2 X Group 3 = 0.0025; Group 2 X Group 4 = 0.0025) there were no statistical differences between the Groups 3 and 4. analysis of adhesion of blood components showed that the Groups 2, 3 and 4 had no statistically significant differences between themselves, but more biocompatible surfaces promoted the surface untreated control (Group 1 X Group 2 = 0.02; Group 1 X Group 3 = 0.04; Group 1 X Group 4 = 0.005). Conclusion The instrumentation with piezoelectric ultrasonic promoted an irregular root surface, but did not negatively affect the adhesion of blood components.