Biomedical subjects
MA Pimenta
Publications and source records attributed to MA Pimenta.
Polarized raman study of single-wall semiconducting carbon nanotubes
Polarized Raman spectra were obtained from a rope of aligned semiconducting single-wall nanotubes (SWNTs) in the vicinity of the D band and the G band. Based on group theory analysis and related theoretical predictions, the G-band profile was deconvolved into four intrinsic SWNT components with the following symmetry assignments: 1549 cm(-1) [E2(E(2g))], 1567 cm(-1) [A(A(1g))+E1(E(1g))], 1590 cm(-1) [A(A(1g))+E1(E(1g))] and 1607 cm(-1) [E2(E(2g))]. The frequency shifts of the tangential G modes from the 2D graphitelike E(2g(2)) frequency are discussed in terms of the nanotube geometry.
Polarized raman study of aligned multiwalled carbon nanotubes
Polarized Raman spectra of high purity aligned arrays of multiwalled carbon nanotubes, prepared on silica substrates from the thermal decomposition of a ferrocene-xylene mixture, show a strong dependence of the graphitelike G band and the disorder-induced D band on the polarization geometry employed in the experiments. The experimental G-band intensity exhibits a minimum at straight theta(m) = 55 degrees in the VV configuration, in good agreement with theoretical predictions of a characteristic minimum at 54.7 degrees for A(1g) modes in single wall nanotubes, where straight theta(m) denotes the angle between the polarization direction and the nanotube axis.
X-ray study of the ferroelastic incommensurate phase of LiKSO4 under uniaxial pressure.
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Raman study of interface roughness in (GaAs)n/(AlAs)n superlattices grown on tilted surfaces: Evidence of corrugation of the (113) interface.
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Raman and birefringence studies of the low-temperature phase transitions in LiK1-xRbxSO4 crystals.
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Optical study of LiKSO4 crystals under uniaxial pressure.
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Frustration on the triangular lattice and incommensurability.
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Low-temperature sequence of phase transitions in LiKSO4 studied by EPR.
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High-temperature phase transitions in LiKSO4.
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