Magnetoelectric coefficient in strontium ruthenate buffered lanthanum modified bismuth ferrite thin films grown by chemical method

This paper focuses on the magnetoelectric coupling (ME) at room temperature in lanthanum modified bismuth ferrite thin film (BLFO) deposited on SrRuO 3-buffered Pt/TiO 2/SiO 2/Si(100) substrates by the soft chemical method. BLFO film was coherently grown at a temperature of 500 °C. The magnetoelectric coefficient measurement was performed to evidence magnetoelectric coupling behavior. Room temperature magnetic coercive field indicates that the film is magnetically soft. The maximum magnetoelectric coefficient in the longitudinal direction was close to 12 V/cmOe. Dielectric permittivity and dielectric loss demonstrated only slight dispersion with frequency due the less two-dimensional stress in the plane of the film. Polarization reversal was investigated by applying dc voltage through a conductive tip during the area scanning. We observed that various types of domain behavior such as 71 ° and 180° domain switching, and pinned domain formation occurred. Copyright © 2009 American Scientific Publishers All rights reserved.

Observation of tags and hybrid layer of a single bottle conventional adhesive system and a self-etching adhesive system, on sound dentin.

This experimental light microscopy study investigated the formation of a hybrid layer and resin tags on sound dentin, after utilization of conventional and self-etching adhesive systems. After restorative procedures, the specimens were decalcified in a formic acid and sodium citrate solution, embedded in paraffin, sectioned at 6-microm thickness and stained by the Brown & Brenn method for analysis and measurement by light microscopy (AXIOPHOT) (400x). The results were statistically analyzed by analysis of variance, at a significance level of 5%. Based on the results, it could be concluded that the conventional adhesive allowed the formation of a thicker hybrid layer than the self-etching adhesive, with similar penetration into the dentinal tubules (resin tags).

Analysis of inventory management in small business auto parts

The objective of this study was to analyze the production process and supply control in order to identify possible gaps and develop a method for managing supplies. The relevance of this research is on the benefits that can obtain by identifying the problems of supply control. The research method used was the case study, which was grounded on tripod semi-structured interviews, on-site observation, and document analysis. This methodology was very suitable because it can be analyzed and cross checked. The possibility of implementation of the proposal obtained from the theoretical framework, that together with the complementary actions suggested here, offers the opportunity to make the process more productive and profitable. This work allowed one to observe the weaknesses in managing the supply chain and at what points to work should be improved. It allowed to use some scientific models in the company object of study in order to improve supply management. © 2011 IEEE.

The University and its libraries: Reactions and resistance to scientific publishers

This paper addresses the relationship of copyright and the right of universities on scientific production. Information and Communication Technologies (ICTs) are causing many changes in the system of scientific communication, such as the creation of Institutional Repositories that aim to gather scientific production in digital format. The University needs quicker ways of spreading academic production and many questions are emerging due to contexts such as the Open Access movement. Thus, this paper questions the positioning of Universities, especially Public Universities, which despite having policies related to intellectual property to protect the transferring forms of research results to society; many times do not have a positioning or a mechanism that regulates the self-deposit of scientific production in these Institutional Repositories. In order to develop this paper, the following issues are addressed: lack of interest of the University in storing scientific production; reports on the relationship of the library with scientific publishing houses; the participation of faculty members and students in supporting the Free Access movement; and initiatives aimed at greater flexibility of copyright to the context of scientific production. In order to follow the development of these issues at international level, it was opted for qualitative research with non-participating direct observation to carry out the identification and description of copyright policy of important publishers from the ROMEO SHERPA site; therefore, it can be observed that there are changes regarding the publishers' flexibility before self-archiving of authors in open access institutional repositories in their universities. Given this scenario, we presente reflections and considerations that involve the progress and mainly the integration of the University and its faculty members; the institution should recommend and guide its faculty members not to transfer their copyrights, but to defend their right of copy to Institutional Repositories along with Publishing Houses.

A study of the precursors and photoactivity of nanostructures of Ti oxides synthesized by the alkaline hydrothermal method

The present study describes the synthesis, characterization and photocatalytic potential of Ti oxide nanostructures of various morphologies and crystalline phases that were synthesized from 4 different precursors by the alkaline hydrothermal method. The materials were characterized by mainly X-ray diffraction (XRD), Raman spectroscopy, scanning and transmission electron microscopy (SEM and TEM), thermogravimetric analysis (TGA) and X-ray absorption spectroscopy (XAS). Also, photocatalytic potential was assessed by rhodamine B photodegradation. The materials obtained from peroxytitanium complexes (PTCs) exhibited a strong dependence on the concentration of KOH ([KOH]) used for synthesis. The pre-formed sheets of the PTCs were critical to the formation of nanostructures such as nanoribbons, and they were also compatible with the rolling up process, which can be utilized to form structures such as nanorods, nanowires or nanotubes. In the rhodamine photodegradation tests, TiO2 anatase nanostructures with six-coor inated Ti were more effective than the titanate ones (five-coordinated), despite having a smaller surface area and fewer OH groups. The lower photoactivity of the titanates was attributed to the presence of five-coordinated titanium species (TiO5), which may act as electron-hole recombination centers. Furthermore, the material with a mixture of TiO2/titanate was shown to be promising for photocatalytic applications. © 2013 by American Scientific Publishers.

Direct in situ observation of the electron-driven synthesis of Ag filaments on α-Ag2 WO4 crystals

In this letter, we report, for the first time, the real-time in situ nucleation and growth of Ag filaments on α-Ag2 WO4 crystals driven by an accelerated electron beam from an electronic microscope under high vacuum. We employed several techniques to characterise the material in depth. By using these techniques combined with first-principles modelling based on density functional theory, a mechanism for the Ag filament formation followed by a subsequent growth process from the nano-to micro-scale was proposed. In general, we have shown that an accelerated electron beam from an electronic microscope under high vacuum enables in situ visualisation of Ag filaments with subnanometer resolution and offers great potential for addressing many fundamental issues in materials science, chemistry, physics and other fields of science.

Solução rápida das ambigüidades GPS para aplicações no posicionamento relativo de linhas de base curtas

Pós-graduação em Ciências Cartográficas - FCT

A contribuição da epistemologia de Gaston Bachelard para o ensino de ciências: uma razão aberta para a formação do novo espírito científico o exemplo na astronomia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

An automatic method for segmentation of fission tracks in epidote crystal photomicrographs

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

On observation of the downconversion mechanism in Er3+/Yb3+ co-doped tellurite glass using thermal and optical parameters

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Controlled Synthesis of Layered Sn3O4 Nanobelts by Carbothermal Reduction Method and Their Gas Sensor Properties

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

The University and its libraries: reactions and resistance to scientific publishers

This paper addresses the relationship of copyright and the right of universities on scientific production. Information and Communication Technologies (ICTs) are causing many changes in the system of scientific communication, such as the creation of Institutional Repositories that aim to gather scientific production in digital format. The University needs quicker ways of spreading academic production and many questions are emerging due to contexts such as the Open Access movement. Thus, this paper questions the positioning of Universities, especially Public Universities, which despite having policies related to intellectual property to protect the transferring forms of research results to society; many times do not have a positioning or a mechanism that regulates the self-deposit of scientific production in these Institutional Repositories. In order to develop this paper, the following issues are addressed: lack of interest of the University in storing scientific production; reports on the relationship of the library with scientific publishing houses; the participation of faculty members and students in supporting the Free Access movement; and initiatives aimed at greater flexibility of copyright to the context of scientific production. In order to follow the development of these issues at international level, it was opted for qualitative research with non-participating direct observation to carry out the identification and description of copyright policy of important publishers from the ROMEO SHERPA site; therefore, it can be observed that there are changes regarding the publishers' flexibility before self-archiving of authors in open access institutional repositories in their universities. Given this scenario, we presente reflections and considerations that involve the progress and mainly the integration of the University and its faculty members; the institution should recommend and guide its faculty members not to transfer their copyrights, but to defend their right of copy to Institutional Repositories along with Publishing Houses.

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.

Structural characterization of Li-MN doped powders prepared by Pechini's method

Pechini's method has been successfully used to prepare Li-doped MgNb2O6(MN) at short time and low temperature. It consists in the preparation of metal citrate solution, which is polymerized at 250°C to form a high viscous resin. This resin was burned in a box type furnace at 400°C/2h and ground in a mortar. Successive steps of calcination up to 900°C were used to form a crystalline precursor. SEM, DTA and XRD were used to characterize the powders. MN precursor powders containing from 0.1 to 5.0 mol% of LiNbO3 additive was prepared aiming better dielectric properties and microstructural characteristics of the PMN prepared from columbite route. SEM analysis showed that particles increased by sintering, forming large agglomerates. The surface area is also substantially reduced with the increase in additive amount above 1.0 mol%. In XRD pattern of the precursor material with 5.0 mol% of additive was observed the LiNbO3 phase of trigonal structure. XRD data were used for Rietveld refinement and a decrease in microstrain and pronounced increase in crystallite size with the increase of LiNbO3 were observed. It is in agreement with the particle morphologies observed by SEM analysis.

Influence of Mg on the structural and optical properties of LiNbO3 thin films grown by polymeric precursor method

A polymeric precursor solution was used to deposit pure and Mg doped LiNbO3 thin films on sapphire substrates by spin-coating. The effects of magnesium addition on crystallinity, morphology and optical properties of the annealed films were investigated. X-ray diffraction patterns indicate the oriented growth of the films. Phi-scan diffraction evidenced the epitaxial growth with two in-plane variants. AFM studies show that the films are very homogeneous, dense and present smooth surfaces. The refractive index and optical losses obtained by the prism coupling method were influenced by the magnesium addition.