Synthesis and structural characterization of Eu(III)-doped Zn7Sb2O12

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

Study of the potentiometric response of the doped spinel Li1.05Al0.02Mn1.98O4 for the optimization of a selective lithium ion sensor

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization of metallic electrical contacts to SnO2 thin films lightly doped with Eu3+ ions, and photo-induced resistivity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Raman and photoluminescence of Er3+-doped SnO2 obtained via the sol-gel technique from solutions with distinct pH

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

On the origin of exciton formation in dye doped Alq(3) OLEDs

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

Structural Characterization of Nanocrystalline Sb-Doped SnO2 Xerogels by Multiedge X-ray Absorption Spectroscopy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synthesis and characterization of Fe(III)-doped ceramic membranes of titanium dioxide and its application in photoelectrocatalysis of a textile dye

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

Lanthanum-doped Bi4Ti3O12 prepared by the soft chemical method: Rietveld analysis and piezoelectric properties

Bi4-xLaxTi3O12 (BLT) thin films and powders with x ranging from 0 to 0.75 were prepared by the polymeric precursor solution. The effect of lanthanum on the structure of BIT powders was investigated by Rietveld Method. The increase of lanthanum content does not lead to any secondary phases. Orthorhombicity of the bismuth titanate (BIT) crystal lattice decreased with the increase of lanthanum content due the reduction of a/b ratio. The BLT films show piezoelectric coefficients of 45, 19, 16 and 10 pm/V for x = 0, 0.25, 0.50 and 0.75, respectively. The piezoelectric response is strongly reduced by the amount of lanthanum added to the system. (c) 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Dielectric behavior of PVDF/POMA blends that have a low doped POMA content

The real (epsilon') and imaginary (epsilon) components of the complex permittivity of blends of PVDF [poly(vinylidene fluoride)] with POMA [poly(o-methoxyaniline)] doped with toluenosulfonic acid (TSA) containing 1, 2.5, and 5 wt % POMA-TSA were determined in the frequency interval between 10(2) and 3 X 10(6) Hz and in the temperature range from -120 up to 120degreesC. It was observed that the values of epsilon' and epsilon had a greater increase with the POMA-TSA content and with a temperature in the region of frequencies below 10 kHz. This effect decreased with frequency and it was attributed to interfacial polarization. This polarization was caused by the blend heterogeneity, formed by conductive POMA-TSA agglomerates dispersed in an insulating matrix of PVDF. The equation of Maxwell-Garnett, modified by Cohen, was used to evaluate the permittivity and conductivity behavior of POMA-TSA in the blends. A strong decrease was observed in POMA-TSA conductivity in the blend, which was bigger the lower the POMA-TSA content in the blend. This decrease could have been caused either by the POMA dedoping during the blend preparation process or by its dispersion into the insulating matrix. (C) 2002 Wiley Periodicals, Inc.

Undoped and calcium doped borate glass system for thermoluminescent dosimeter

Borate glasses present an absorption coefficient very close to that of human tissue. This fact makes some borates ideal materials to develop medical and environmental dosimeters. Glass compositions with calcium tetraborate (CaB4O7) and calcium metaborate (CaB2O4), such as the xCaB(4)O(7) - (100-x)CaB2O4 System (0 <= x <= 100 wt%) were obtained by the traditional melting/quenching method. A phenomenon widely known as the 'boron anomaly' was observed in our thermal analysis measurements, as indicated by the increase of T, and the appearance of a maximum value in the composition with 40 wt% of CaB2O4. The Dy doped and Li co-doped 80CaB(4)O(7)-20CaB(2)O(4) (Wt%) glass samples were studied by the thermoluminescence technique. The addition of Dy improved the signal sensitivity in about three times with respect to the undoped glass sample. The addition of Li as a co-dopant in this glass caused a shift to a lower temperature of about 20 degrees C in the main glow peak. The structural analysis of the 80CaB(4)O(7)-20CaB(2)O(4) (wt%) undoped and doped samples were studied through infrared absorption. We have noted an increase in the coordination number of the boron atoms from 3 to 4, i.e., the conversion of the BO3 triangular structural units into BO4 tetrahedra. (c) 2006 Elsevier B.V. All rights reserved.

Determination of the photoinduced birefringence and of the refractive index by Brewster method of epoxy resin doped with CdS

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Phase transition and dielectric properties of La-doped Pb(Zr, Ti)O-3 antiferroelectric ceramics

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

Dosimetric properties of UV irradiated calcium co-doped borate glass-ceramic

The thermoluminescence (TL) response of Dy and Li doped 20CaB(4)O(7)-80CaB(2)O(4) (Wt%) glass-ceramic irradiated with ultraviolet (UV) radiation was studied. In order to act as TL activator ions, the Dy and Li ions were included in the matrix during the melting process to increase its TL efficiency. A single crystalline CaB2O4 phase was present in the glass-ceramic as determined by X-ray diffraction (XRD). The glass-ceramic 20CaB(4)O(7)-80CaB(2)O(4):Dy,Li wt% (named 20CBO7:Dy,Li) is a newly prepared TL material. Its thermoluminescent dosimetric characteristics have shown a linear response under UV radiation exposure and a good TL signal reproducibility, thus proving to be a promising material for using as an ultraviolet radiation dosimeter. (C) 2007 Elsevier B.V. All rights reserved.

Biological Response to Wollastonite Doped alpha-Tricalcium Phosphate Implants in Hard and Soft Tissues in Rats

The biological response following subcutaneous and bone implantation of beta-wollastonite(beta-W)-doped alpha-tricalcium phosphate bioceramics in rats was evaluated. Tested materials were: tricalciurn phosphate (TCP), consisting of a mixture of alpha- and beta-polymorphs; TCP doped with 5 wt. % of beta-W (TCP5W), composed of alpha-TCP as only crystalline phase; and TCP doped with 15 wt. % of beta-W (TCP15), containing crystalline alpha-TCP and beta-W. Cylinders of 2x1 mm were implanted in tibiae and backs of adult male Rattus norvegicus, Holtzman rats. After 7, 30 and 120 days, animals were sacrificed and the tissue blocks containing the implants were excised, fixed and processed for histological examination. TCP, TCP5W and TCP15W implants were biocompatible but neither bioactive nor biodegradable in rat subcutaneous tissue. They were not osteoinductive in connective tissue either. However, in rat bone tissue beta-W-doped alpha-TCP implants (TCP5W and TCP15W) were bioactive, biodegradable and osteoconductive. The rates of biodegradation and new bone formation observed for TCP5W and TCP15W implants in rat bone tissue were greater than for non-doped TCP.

Schottky emission in nanoscopically crystallized Ce-doped SnO2 thin films deposited by sol-gel-dip-coating

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)