Electron Positron Annihilation
Mostrando 1-7 de 7 artigos, teses e dissertações.
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1. Polydimethylsiloxane Membranes Containing Multi-walled Carbon Nanotubes for Gas Separation
Polydimethylsiloxane (PDMS) membranes with different concentrations of multi-walled carbon nanotubes were prepared in order to evaluate their gas separation performances. Mixed matrix membranes were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transformed infrared, positron annihilation lifetime and Raman spectroscopies
Mat. Res.. Publicado em: 17/08/2017
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2. Positron Annihilation Spectroscopy Study on Annealing Effect of CuO Nanoparticles
The microstructure and defects of CuO nanoparticles under isochronal annealing were investigated by positron annihilation spectroscopy (PAS), X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD and SEM results indicated that the average grain sizes of CuO nanoparticles grew slowly below 800 °C, and then increased rapidly with the annealing t
Mat. Res.. Publicado em: 23/02/2016
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3. Study of the momentum distribution of bound electrons by angle-energy correlation of electro-positron annihilation radiation / Estudo da distribuição de momento de elétrons ligados por correlação ângulo-energia da radiação de aniquilação elétron-pósitron
Há várias evidências experimentais da existência de matéria escura no universo. Apesar destas evidências, pouco se sabe sobre sua constituição, sabendo-se apenas que interage gravitacionalmente, mas não eletromagneticamente. Neste projeto, investigamos a possibilidade da matéria escura ser composta por partículas supermassivas e fortemente interag
Publicado em: 2010
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4. Espalhamento de Férmions sob Influencia da Violação de Lorentz no Setor Fotônico / Scattering of Fermions under Influence of Violation Lorentz Sector Photonic
The standard model extension is a theoretical framework which includes the possibility of Lorentz symmetry violation in the Standard Model of elementary interactions. In electrodynamics, this possibility is represented by the term, KμFμF, that violates Lorentz symmetry without jeopardizing CPT symmetry, and the term "μvAμ@A, which violate
Publicado em: 2010
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5. AvaliaÃÃo da eficÃcia do avental equivalente a 0,5 mm de chumbo em tomografia por emissÃo de PÃsitrons atravÃs de simulaÃÃes Monte Carlo / Evaluation of the effectiveness of 0.5 mm lead equivalent apron in positron emission tomography by Monte Carlo simulation
In Positron Emission Tomography (PET), medical staff is exposed to 511 keV photons, which is a result of the positron-electron annihilation process. This energy is about four times the 140 keV commonly found in studies based on Single Photon Emission Computed Tomography (SPECT). Despite these different energy levels, 0.5 mm lead equivalent aprons have being
Publicado em: 2008
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6. Study of the electron-positron annihilation coincidence peak two-dimensional pofile
Positron annihilation radiation profi le in aluminum was observed with a pair of Ge detectors in coincidence. 22Na was used as a source of positron and the two-dimensional gamma energy spectrum wasfi tted using a model function. Annihilation components of positron at rest with conduction band, 1s, 2s, and 2p electrons were observed. The in-flight positron an
Brazilian Journal of Physics. Publicado em: 2004-09
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7. Source theory analysis of electron-positron annihilation experiments
The phenomenological viewpoint already applied to deep inelastic scattering is extended to the discussion of electron-positron annihilation experiments. Some heuristic arguments lead to simple forms for the pion differential cross section that are in reasonable accord with the published experimental data in the energy interval 3-4.8 Gev.