Hyperfine Structure
Mostrando 1-12 de 50 artigos, teses e dissertações.
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1. The Structural and the Magnetic Properties of Aluminum Substituted Yttrium Iron Garnet
In this paper, Y3AlxFe5-xO12 powders with x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 were prepared via solid state reaction method. X-ray diffraction, Vibrating Sample Magnetometry, and Mössbauer Spectroscopy were used to study their structural and magnetic properties. The XRD patterns of the samples show single phase structure with decreasing lattice constant wh
Mat. Res.. Publicado em: 15/03/2018
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2. Estudo da Estrutura Local dos SÃtios de Ferro em Ligas FeCrMo por Espectroscopia MÃssbauer e DifraÃÃo de Raios -X / Study of the local structure of iron sites in Fe-Cr-Mo alloys by MÃssbauer Spectroscopy and X-ray Diffraction
Ligas Fe-Cr-Mo sÃo amplamente utilizadas na fabricaÃÃo de tubulaÃÃes para a indÃstria petroquÃmica nos processos de transporte e refino do petrÃleo devido a uma combinaÃÃo de propriedades como dureza, tenacidade e resistÃncia à fluÃncia e à corrosÃo em altas temperaturas. Atualmente, a liga Fe-9Cr-1Mo à a mais comumente utilizada. Contudo, em
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/06/2011
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3. Study of the structure of free radicals in gamma: irradiated amino acid derivatives
Electron paramagnetic resonance spectroscopy has been used for the study of the free radicals produced in the powders of L-arginine monohydrochloride, ala-ala and DL-β-leucine gamma-irradiated at room temperature. The structures of the radicals formed in compounds were determined as NH2(NH)NHCHCH2CH2CH(NH2)COOH, CH3CHCOOH and (CH3)2C CH(NH2)CH2COOH respecti
Brazilian Journal of Physics. Publicado em: 2010-12
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4. Theoretical studies of the EPR parameters for Ni2+ and Co+ in MgO
The electron paramagnetic resonance (EPR) parameters (g factors and the hyperfine structure constants) for Ni2+ and Co+ in MgO are theoretically studied from the perturbation formulas of these parameters for a 3d8 ion in octahedral crystal-fields. In the computations, the ligand orbital and spin-orbit coupling contributions are taken into account using the c
Brazilian Journal of Physics. Publicado em: 2010-09
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5. Theoretical studies of the local structure and the EPR parameters for substitutional Mo5+ in TiO2
The electron paramagnetic resonance(EPR) parameters g-factors g i(i = x,y,z) and the hyperfine structure constants Ai for the substitutional Mo5+ in rutile are theoretically studied from the perturbation formulas of these parameters for a d¹ ion in a rhombically compressed octahedron. On the basis of the studies, The oxygen octahedron around Mo5+ is found t
Brazilian Journal of Physics. Publicado em: 2010-09
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6. Identification of free radicals induced by gamma irradiation in amino acid derivatives
Powders of N- acetyl- L- leucine and N- methyl- L- glutamic acid were gamma irradiated and the free radicals formed were investigated at room temperature by electron paramagnetic resonance technique. The free radicals formed in compounds were attributed to the (CH3)2CCH2CH(NHCOCH3)COOH and HOOCCH2CH2C (NHCH3)COOH radicals respectively. Both radicals are very
Brazilian Journal of Physics. Publicado em: 2010-09
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7. EPR study of gamma induced radicals in amino and iminodiacetic acid derivatives
In this study, electron paramagnetic resonance spectroscopy was used to investigate free radicals formed in gamma irradiated L-glutamine hydrochloride, iminodiacetic acid hydrochloride and N-(2-hyroxyethyl) iminodiacetic acid powders. The free radicals produced in L-glutamine hydrochloride powders were attributed to the CH2CHCOOH radical; and those in iminod
Brazilian Journal of Physics. Publicado em: 2009-09
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8. Simulataneous temperature measurements of the upper mesosphere obtained lidar and airglow in the Brazilian low latitude sector / Medidas simultâneas de temperatura na mesosfera superior através de radar de laser e luminescência atmosférica em baixas latitudes no setor brasileiro
We present temperature measurements of the upper mesosphere obtained by lidar and airglow in the low latitude Brazilian sector over a period of two years. In the 80-110 km region, free sodium atoms are abundant enough to allow probing of the Doppler broadened hyperfine structure of the D2 resonance transition by ground-based lidar. The lidar technique consis
Publicado em: 2009
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9. Controlled reduction of LaFe xMn yMo zO3/Al2O3 composites to produce highly dispersed and stable Fe0 catalysts: a Mössbauer investigation
In this work, controlled reduction of perovskites supported on Al2O3 was used to prepare thermally stable nanodispersed iron catalysts based on Fe0/La2O3/Al2O3. The perovskites composites LaFe0.90Mn0.08Mo0.02O3(25, 33 and 50 wt (%)) /Al2O3 and LaFe0.90Mn0.1O3(25 wt (%)) /Al2O3 were prepared and characterized by XRD, BET, TPR, SEM and Mössbauer spectroscopy.
Materials Research. Publicado em: 2008-06
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10. Luminescence and paramagnetic centers in antigorite and Lizardite, two menbers of serpentine group: a comparative study / Estudo comparativo entre as propriedades dos centros luminescentes e paramagnéticos da antigorita e da lizardita do grupo da SERPENTINA: `Mg IND.3´[Si IND.2´`O IND.5´]`(OH) IND.4´
In this work, we are describing crystals luminescent properties of Antigorite (monoclinic, Mg3-x[Si2O5](OH)4-2x) and Lizardite (triclinic, Mg3[(Si,Fe)2O5](OH)4). They were studied simultaneously applying several techniques, like: Thermoluminescence (TL), Optical Absorption (OA), Electron Paramagnetic Resonance (EPR), X-rays diffraction and Inductively Couple
Publicado em: 2008
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11. Estudos estruturais de histatina-5 e seu análogo, TOAC0-histatina-5: interação com metais e sistemas biomiméticos / Structural studies of Histatin-5 and its analogue, TOAC0-Histatin-5: interaction with metals and biomimetic systems
The mechanism of action of histatin-5 (Hst-5), an antifungal antimicrobial peptide from human saliva is not completely clarified. Circular dichroism (CD), fluorescence, and electron paramagnetic resonance (EPR) were used to examine the conformational behavior of Hst-5 and its analogue containing the paramagnetic amino acid TOAC at the N-terminus (TOAC0-Hst-5
Publicado em: 2008
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12. Investigation of hyperfine interactions in pure silicon and NTD silicon by means of perturbed angular γ-γ correlation spectroscopy / Investigação de interações hiperfinas em silício puro e silício NTD pela técnica de correlação angular gama-gama perturbada
In the present work, a microscopic investigation of hyperfine interactions in single crystal silicon samples was carried out by means of Perturbed Angular γ-γ Correlation technique (PAC), which is based in hyperfine interactions. In order to achieve these measurements, it was used 111In ->111Cd radioactive probe nuclei, which decay through the we
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/02/2007