Experimental evidence of transition between dynamical and kinematical diffraction regimes in ion-implanted Si observed through X-ray multiple-beam diffraction mappings

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMAIn this paper, the dependence of a Laue diffraction streak on the crystalline perfection of Xe-implanted Si(001) substrates is presented, based on the observation in the X-ray multiple diffraction (XRMD) mappings, as an experimental evidence of the transition between dynamical and kinematical diffraction regimes. A direct observation of the implanted region by transmission electron microscopy revealed an amorphous Si layer, which recrystallizes into a heavily twinned and faulted microstructure after thermal treatment at 800 degrees C. Besides the lattice damages, the annealing induces the formation of Xe bubbles. Both singularly affect the XRMD pattern, primarily the fourfold streaks profile of the (000)(002)(1 (1) over bar(1) over bar)(1 (1) over bar3) four-beam simultaneous case when compared with the pristine Si pattern, highlighting the intra-and inter-block diffractions and the role played by the primary extinction effect. Such features provide information on the dominant diffraction regime. The findings are also discussed and compared to the conventional reciprocal space mappings via the asymmetric Si(113) reflection. Published by AIP Publishing.In this paper, the dependence of a Laue diffraction streak on the crystalline perfection of Xe-implanted Si(001) substrates is presented, based on the observation in the X-ray multiple diffraction (XRMD) mappings, as an experimental evidence of the transition between dynamical and kinematical diffraction regimes. A direct observation of the implanted region by transmission electron microscopy revealed an amorphous Si layer, which recrystallizes into a heavily twinned and faulted microstructure after thermal treatment at 800 degrees C. Besides the lattice damages, the annealing induces the formation of Xe bubbles. Both singularly affect the XRMD pattern, primarily the fourfold streaks profile of the (000)(002)(1 (1) over bar(1) over bar)(1 (1) over bar3) four-beam simultaneous case when compared with the pristine Si pattern, highlighting the intra-and inter-block diffractions and the role played by the primary extinction effect. Such features provide information on the dominant diffraction regime. The findings are also discussed and compared to the conventional reciprocal space mappings via the asymmetric Si(113) reflection.1091415CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMACNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMASem informaçãoSem informaçãoSem informaçãoThe authors would like to thank the financial support of the Brazilian agencies CNPq, FAPESP, FAPEMA, the LNLS (XRD2 beamline) staff and Sérgio Morelhão for useful discussions

Lattice strain distribution resolved by X-ray Bragg-surface diffraction in an Si matrix distorted by embedded FeSi2 nanoparticles

Out-of-plane and primarily in-plane lattice strain distributions, along the two perpendicular crystallographic directions on the subsurface of a silicon layer with embedded FeSi2 nanoparticles, were analyzed and resolved as a function of the synchrotron X-ray beam energy by using omega:phi mappings of the (111) and (111) Bragg-surface diffraction peaks. the nanoparticles, synthesized by ion-beam-induced epitaxial crystallization of Fe+-implanted Si(001), were observed to have different orientations and morphologies (sphere-and plate-like nanoparticles) within the implanted/recrystallized region. the results show that the shape of the synthesized material singularly affects the surrounding Si lattice. the lattice strain distribution elucidated by the nonconventional X-ray Bragg-surface diffraction technique clearly exhibits an anisotropic effect, predominantly caused by plate-shaped nanoparticles. This type of refined detection reflects a key application of the method, which could be used to allow discrimination of strains in distorted semiconductor substrate layers.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPEMACoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)UNIFESP, Inst Ciencia & Tecnol ICT, BR-12231280 Sao Jose Dos Campos, SP, BrazilUniv Fed Maranhao, Dept Fis CCET, BR-65085580 Sao Luis, MA, BrazilUniv Fed Maranhao, CCSST, BR-65900410 Imperatriz, MA, BrazilUniv Fed Rio Grande do Sul, Inst Fis, Programa Posgrad Ciencias Mat PGCIMAT, BR-91501970 Porto Alegre, RS, BrazilCEA, Leti Minatec Campus, F-38054 Grenoble, FranceUniv Estadual Campinas, Inst Fis Gleb Wataghin IFGW, BR-13083859 Campinas, SP, BrazilUNIFESP, Inst Ciencia & Tecnol ICT, BR-12231280 Sao Jose Dos Campos, SP, BrazilCAPES: 2358-09-3Web of Scienc

Effect of an extract of Centella asiatica on the biodistribution of sodium pertechnetate (Na^99mTcO₄) and on the fixation of radioactivity on blood constituents

This study evaluates the effects of an acute treatment with a Centella asiatica (CA) extract on the biodistribution of the radiopharmaceutical Na99mTcO4 and on the fixation of technetium-99m on blood constituents. Wistar rats were treated with CA extract and, 1 hour after, Na99mTcO4 was administered; organs/tissues were withdrawn and weighted. The radioactivity was counted to calculate the percentage of activity per gram (%ATI/g). Also, blood samples were withdrawn, plasma (P), blood cells (BC), insoluble fraction (IF) and soluble fractions of P and BC were isolated and the radioactivity was counted to calculate the percentage of activity (%ATI). Data indicated that the acute treatment with CA extract changed significantly (p99mTcO4 and the fixation of the technetium-99m on blood constituents in an acute treatment

EDXRF study of Tupi-Guarani archaeological ceramics.

A set of indian Brazilian pottery fragments belonging to Tupi-Guarani tradition has been studied by an archaeometric non-destructive technique. The pottery fragments were accidentally discovered in the Santa Dalmacia farm, sited near Cambé city at the north of Paraná Brazilian state. Each one of these fragments came from different ceramic recipients and their physical characteristics are very similar. The EDXRF measurements were performed employing both an X-ray tube and three radioisotope sources (Fe, Cd and Pu). The compositional data of the ceramics paste and pigments is investigated. For detection of the elements within the ceramic paste, the fragments were irradiated at the center of the lateral section, while several superficial areas with remaining plastic decoration were also chosen and irradiated at the convex and concave sides of each fragment. A paste-subtracted compositional data of the remaining pigments was statically extracted from the XRF analysis of each area. A program based on the graphic polygonal representation method was developed and used to correlate the representative intensity data of each fragment.Um conjunto de fragmentos cerâmicos indígenas brasileiros pertencentes à Tradição Tupi-Guarani foi estudado por uma técnica arqueométrica não destrutiva. Os fragmentos cerâmicos foram descobertos acidentalmente na fazenda Santa Dalmácia, situada próximo da cidade de Cambé, no norte do estado do Paraná. Cada um desses fragmentos veio de diferentes recipientes cerâmicos e suas características físicas são muito similares. As medidas EDXRF foram realizadas empregando tanto um tubo de raios X como três fontes de radioisótopos (55Fe, 109Cd e 238Pu). Os dados de composição da pasta cerâmica e dos pigmentos são investigados. Para detecção dos elementos contidos na pasta cerâmica, os fragmentos foram irradiados no centro da secção lateral, enquanto algumas áreas com decoração plástica remanescente também foram escolhidas e irradiadas nos lados convexo e côncavo de cada fragmento. Foram obtidas as composições dos pigmentos remanescentes em cada área analisada, subtraindo-se do espectro XRF da área considerada o espectro XRF da pasta cerâmica. Um programa baseado no método de representação poligonal gráfica foi desenvolvido e usado para correlacionar a intensidade representativa de cada fragmento

The effect of an extract from Ganoderma lucidum (reishi) on the labeling of blood constituents with technetium-99m and on the survival of Escherichia coli

This study evaluated effects of an aqueous extract of Ganoderma lucidum (reishi) on the labeling of blood constituents with technetium-99m (99mTc) and on the survival of cultures of Escherichia coli treated with stannous chloride. Blood samples from Wistar rats were treated with reishi extract, radiolabeling procedure was performed, plasma (P), blood cells (BC) and insoluble (IF) and soluble (SF) fractions of P and BC were separated. The radioactivity was counted for the determination of the percentages of radioactivity (%ATI). Cultures of Escherichia coli AB1157 were treated with stannous chloride in the presence and absence of reishi extract. Blood samples and bacterial cultures treated with NaCl 0.9% were used as controls. Data indicated that reishi extract altered significantly (p99mTc and protecting bacterial cultures against oxidative damage induced by stannous chloride

Assessment of phase transition and thermal expansion coefficients by means of secondary multiple reflections of Renninger scans

This paper reports the successful extension of the basis of the X-ray multiple diffraction phenomenon in the assessment of structural phase transitions and the determination of thermal expansion coefficients along three crystallographic directions, using synchrotron radiation Renninger scans. Suitable simultaneous four-beam cases have accurately resolved the lattice-parameter variation in a nearly perfect single-crystal Rochelle salt using a high-stability temperature apparatus. Secondary reflections observed in the Renninger patterns, chosen by their sensitivity to the shifts in angular position as a function of temperature, have allowed the detection of a monoclinic to orthorhombic phase transition, as well as subtle expansions of all the basic lattice parameters, i.e. without having to carry out measurements on each crystal axis. The thermal expansion coefficients have been estimated from the linear fit of the temperature dependence of the lattice parameters, and are in agreement with those reported in the literature5261271127

X-ray phase measurements as a probe of small structural changes in doped nonlinear optical crystals

X-ray multiple diffraction experiments with synchrotron radiation were carried out on pure and doped nonlinear optical crystals: NH(4)H(2)PO(4) and KH(2)PO(4) doped with Ni and Mn, respectively. Variations in the intensity profiles were observed from pure to doped samples, and these variations correlated with shifts in the structure factor phases, also known as triplet phases. This result demonstrates the potential of X-ray phase measurements to study doping in this type of single crystal. Different methodologies for probing structural changes were developed. Dynamical diffraction simulations and curve fitting procedures were also necessary for accurate phase determination. Structural changes causing the observed phase shifts are discussed.FAPESPCNPqLNLS - Brazilian Synchrotron Light Laborator

On the quantitative phase analysis and amorphous content of triacylglycerols materials by X-ray Rietveld method

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPEMA - FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe characterization of fat components becomes very useful for formulation of shortening, margarines and fat products due to their unique properties of plasticity, texture, solubility, and aeration. However, X-ray diffraction experiments on such materials are usually limited to a qualitative evaluation of the polymorphic properties based only on the characteristic d-spacing peak intensities. In this work, interesting results based on the Rietveld Method have supported both a Quantitative Phase Analysis and Degree of Crystallinity study on industrial and academic appealing samples, such as triacylglycerol standards, fully hydrogenated vegetable oils (hardfats) and cocoa butter. This useful approach to the area of oils and fats can provide valuable information about the polymorphism and its relationship to the application of lipid materials in food science and technology. Here, the discrimination between beta and beta' polymorphs on samples made of mixtures or blended hardfats was attained, and the results have shown a relevant contrast in comparison to a purely qualitative approach. Assessment of amorphous content on cocoa butter samples was achieved by isolating its contribution from the total X-ray diffraction background via mathematical tools during the whole pattern fitting.2125160CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPEMA - FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPEMA - FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAUL