Synchrotron Radiation
Mostrando 37-48 de 109 artigos, teses e dissertações.
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37. Eletronic charge density at high resolution x-rays diffraction and topological anlysis using the multipole model in single crystals compounds of biological interest / Densidade eletrônica por difração de raios-x à alta resolução e análise topológica com modelo multipolar em compostos monocristalinos de interesse biológico
The bonding properties of the transition metal complex Cu(I1)-L-alanyl-L-valine and the Taurine compound have been determined by high resolution x-ray diffraction. The charge density analysis is performed using the Hansen-Coppens multipole model for both, the topological study of the electron density p(f) and the orbital populations analysis of the transitio
Publicado em: 2003
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38. Estudos espectroscopicos em atomos e moleculas : calculos de forças de osciladores e tempos de vida para ions de Si, medidas de momento de recuo de ions em atomos de Cs resfriados a laser e medidas de multicoincidência em moleculas de N2 e O2
This thesis comprises atomic and molecular physics studies, both theoretical and experimental. Weighted oscillator strengths and lifetimes were calculated for the following silicon ions: Si I, Si XI, Si XII and Si XIII. The calculations were carried out in a multiconfiguration Hartree-Fock relativistic aproach. The eletrostatic parameters were optimized by a
Publicado em: 2003
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39. Determinação qualitativa e quantitativa de metais em plantas medicinais por fluorescencia de raios-X e voltametria de redissolução anodica
Avaliou-se a presença de contaminantes inorgânicos em plantas medicinais destinadas à produção de fitoterápicos por fluorescência de raios-X de energia dispersiva (do inglês, energy dispersive X-ray fluorescence, EDXRF) e fluorescência de raios-X com luz síncrotron (do inglês, synchrotron radiation X- Ray fluorescence, SYXRF), assim como se estabe
Publicado em: 2003
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40. Coherent plasma processes in active galactic nuclei
The physics of active galactic nuclei (AGN) and related objects is one of the most actively pursued areas of astrophysics. Their large luminosities over the entire electromagnetic spectrum combined with extremely short time variability has stimulated a large number of astrophysicists to propose rather unconventional ideas. A variety of radiation mechanisms s
Brazilian Journal of Physics. Publicado em: 2002-12
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41. Espectroscopia de multicoincidencia aplicada ao estudo de moleculas
The main purpose of this thesis is to study selective photo-fragmentation processes of free molecules excited by synchrotron radiation using multi-coincidence spectros-copy. Below are summarized some original and important contributions of this work: 1) We show for the first time experimental evidences of ultrafast dissociation in water molecule after O1s ®
Publicado em: 2002
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42. ANALYSIS OF REACTIONS IN THE FE-ZN SYSTEM THROUGH X-RAYS DIFFRACTION IMAGING IMAGE PROCESSING / ANÁLISE DAS REAÇÕES DO SISTEMA FE-ZN ATRAVÉS DE DIFRAÇÃO DE RAIOS-X SENSÍVEL À POSIÇÃO E PROCESSAMENTO DE IMAGENS
O processo de galvanização por imersão a quente é uma técnica industrial largamente utilizada para proteger componentes de aço expostos à corrosão ambiental. Este processo envolve reações complexas, cujos mecanismos ainda são motivo de debate. A boa performance do revestimento está diretamente relacionada com as fases intermetálicas presentes no
Publicado em: 2002
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43. Synchrotron radiation X-ray multiple diffraction in the study of KDP phase transition induced by electric field
In this work, the application of the X-ray multiple diffraction technique using synchrotron radiation at Laboratório Nacional de Luz Síncrotron (LNLS) to study KDP phase transition induced by electric field is discussed. A Huber three-axis (omega, phi, 2theta) diffractometer mounted on a table which rotates around the incident beam allows to measure Rennin
Materials Research. Publicado em: 2001-01
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44. Sintese e caracterização de preformas de silica-germania obtidas por deposição fase-vapor (VAD)
This research reports the study of deposition parameters of V AD (Vapor -phase Axial Deposition) silica-germanium and their correlation with structural properties. Characterization studies were conducted by small-angle X-ray scattering (SAXS), X-ray difftaction (XRD), scanning electronic microscopy (SEM), and X-ray fluorescence spectroscopy (XRF). The result
Publicado em: 2001
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45. Difração multipla de raios-X no estudo de ordenamento em ligas semicondutoras e defeitos em semicondutores implantados
The aim of this work is to develop the X-ray multiple diffraction, as a new technique to characterize semiconductors wafers submitted to ion implantation and, epitaxial layers that presents atomic ordering. The technique was also of great usefulness in the study of the heterostucture lattice coherence. The sensitivity of the Bragg-surface diffraction (BSD) c
Publicado em: 1999
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46. Diagrama Renninger com radiação de freamento de eletrons e sincrotron no estudo de estruturas heteroepitaxiais
In this work, Renninger scans obtained with Bremsstrahlung and synchrotron radiation were used to study semiconductor heteroepitaxial structures. The program MULTX was implemented to provide Renninger scan simulations and it is based on the iterative method to calculate X-ray multiple diffraction intensities. The polarization factor for the synchrotron radia
Publicado em: 1994
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47. Geração de fotons muito duro por espalhamento Compton inverso da radiação sincrotron
The most efficient mechanism to generate photons in the 100 MeV energy range is by Inverse Compton scattering (ICS) of laser from relativistic electron. The energy of the emitted photons can be increased by raising either the energy of the electron, which is very expensive, or that of the photon. with the suggestion (S. Caticha-Ellis, 1983) that intense X-ra
Publicado em: 1993
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48. Protein microcrystal diffraction and the effects of radiation damage with ultra-high-flux synchrotron radiation.
By using ultra-high-flux synchrotron x-radiation from a wiggler source, good Laue diffraction data have been obtained from protein microcrystals of size 30 X 35 X 10 microns3, mounted wet in glass capillaries. At the flux level of 10(13)-10(14) photons per sec/mm2, the radiation damage is still low enough to allow a large survey of reciprocal space for a mic