Exchange Couplings
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Transições de fase hádron-quark em estrelas de nêutrons
Recent advances on the field of high energy physics have enabled the study of matter under extreme conditions and, in this context, new states of matter are being discovered and speculated upon. Among these hypothetical states of matter is the one of deconfined quarks in high densities and/or temperatures. An environment with extreme densities and low temper
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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2. Electron paramagnetic resonance studies at X- and Q- bands of the dinuclear compounds Cu2(TzTs)4 and [Cu(flu)2DMF]2 / Estudo através da técnica de ressonância paramagnética eletrônica, em bandas X e Q, dos compostos dinucleares Cu2(TzTs)4 e [Cu(flu)2DMF]2
Esta tese relata um estudo pormenorizado, efetuado através da técnica de Ressonância Paramagnética Eletrônica (RPE) em bandas X (~ 9.5 GHz) e Q (~ 34.5 GHz), de amostras nas formas cristalina e pulverizada dos compostos dinucleares Cu2(TzTs)4, C40H36Cu2N8O8S8, e [Cu(flu)2DMF]2, C62H50Cu2F12N6O10. Tratamentos meticulosos dos espectros de RPE pertinentes
Publicado em: 2009
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3. Experimental determination of the nuclear density of 6,7Li nuclei / Determinação experimental da densidade nuclear dos isótopos 6,7 Li
In this work, the elastic and quasi-elastic cross sections for the systems 6,7Li +120 Sn, for the near barrier energies, ELAB = 25.0; 20.5 and 19.5 MeV, have been measured. The data have been analyzed in the framework of the parameter free São Paulo potential, which takes in account the non-local exchange effects in first order. From the quasi-elastic data
Publicado em: 2008
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4. MagnetoresistÃncia em filmes e multicamadas magnÃticas
In this master dissertation, we have studied, at room temperature, magnetic and transport properties of metallic films and multilayer of different structures such as: single layer thin films, coupled trilayer, ferromagnetic/antiferromagnetic bilayer and spin valve. Phenomenological models, which take in account the most relevant magnetic free energy terms, w
Publicado em: 2005
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5. Compensation temperature of the mixed-spin ising model on the hexagonal lattice
We studied a layered mixed-spin Ising model, with spins s = 1/2 and S = 1, distributed on the sites of a hexagonal lattice. For this spin arrangement, any spin at one lattice site has two nearest-neigbor spins of the same type, and four of the other type. We assumed that the exchange interaction between spins s and S is antiferromagnetic, with the value J1.
Brazilian Journal of Physics. Publicado em: 2004-06
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6. Study of phospholipid structure by 1H, 13C, and 31P dipolar couplings from two-dimensional NMR.
Various motionally averaged 31P-1H, 13C-1H, 1H-1H, and 31P-13C dipolar couplings were measured for natural-abundance and unoriented phosphocholine in the L alpha phase. The couplings were obtained and assigned by a variety of advanced and partly novel two-dimensional solid-state NMR experiments. Whereas 31P-1H and 31P-13C dipolar couplings provide long-range
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7. Detection of N-H···N hydrogen bonding in RNA via scalar couplings in the absence of observable imino proton resonances
Hydrogen bond networks stabilize RNA secondary and tertiary structure and are thus essentially important for protein recognition. During structure refinements using either NMR or X-ray techniques, hydrogen bonds were usually inferred indirectly from the proximity of donor and acceptor functional groups. Recently, quantitative heteronuclear J(N,N)-HNN COSY NM
Oxford University Press.
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8. Iron-sulfur proteins: spin-coupling model for three-iron clusters.
Recent Mössbauer and EPR studies of two ferredoxins and of aconitase have given evidence for a three-iron cluster, probably of a [3Fe-3S] type. The studies of the oxidized EPR-active centers have shown that the three iron sites are characterized by significantly different magnetic hyperfine coupling constants. For the ferredoxin from Azotobacter vinelandii,
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9. Quaternary structure of hemoglobin in solution
Many important proteins perform their physiological functions under allosteric control, whereby the binding of a ligand at a specific site influences the binding affinity at a different site. Allosteric regulation usually involves a switch in protein conformation upon ligand binding. The energies of the corresponding structures are comparable, and, therefore
The National Academy of Sciences.
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10. Improvements in Tests of Long-Range Charge Independence
The procedure used to determine the pionnucleon coupling constant g2 from multi-energy fits to nucleon-nucleon (N-N) scattering data has been shortened without a material loss of accuracy. The g2 presetting effect is discussed in connection with the limited accuracy of g2 determinations in general and the possibilities of the “optimized polynomial expansio
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11. Detection of Cl- binding to band 3 by double-quantum-filtered 35Cl nuclear magnetic resonance.
We have applied double-quantum-filtered (DQF) NMR of 35Cl to study binding of Cl- to external sites on intact red blood cells, including the outward-facing anion transport sites of band 3, an integral membrane protein. A DQF 35Cl NMR signal was observed in cell suspensions containing 150 mM KCl, but the DQF signal can be totally eliminated by adding 500 micr