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  • Author or Editor: A. G. C. Pereira x
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Summary  

We introduce a simple variation of Doeblin's condition, Condition D*, that assures the uniform ergodicity of a Markov chain. It is also shown that for non-homogeneous chains our conditions are equivalent to Dobrushin's weak ergodic coefficient.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. R. Pereira
,
S. C. Conceiç?o
,
R. T. Lopes
,
M. J. Anjos
,
L. F. Oliveira
,
H. S. Rocha
, and
C. A. Perez

Summary  

The X-ray fluorescence microtomography (XRFMT) is a non-destructive technique, based on the detection of X-ray fluorescence emitted by the elements in the sample, and it is used to complement other techniques for sample characterization. In this work some tissues of human breast (healthy tissue, benign tumor and malignant tumor) have been analyzed in order to verify the efficiency of the system in the determination of the elemental distribution in these types of samples. The experiments were performed at the X-ray fluorescence beam line (D09B-XRF) of the Brazilian Synchrotron Light Source (LNLS), Campinas, Brazil. A white beam was used for the excitation of the elements and an HPGe detector detected the fluorescence photons. The incident beam was monitored by an ionization chamber and a fast scintillator detector was used to detect the transmitted radiation. All the tomographies have been reconstructed using a filtered-back projection algorithm. In the tissues samples, the elements of higher concentration were Zn, Cu and Fe.

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Journal of Thermal Analysis and Calorimetry
Authors:
F. S. M. Sinfrônio
,
J. C. O. Santos
,
L. G. Pereira
,
A. G. Souza
,
M. M. Conceiçăo
,
V. J. Fernandes Jr.
, and
V. M. Fonseca
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