Relative Dielectric Constant
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Pseudopotential Study of CdTe Quantum Dots: Electronic and Optical Properties
The present contribution reports on the electronic and optical properties of zinc-blende CdTe quantum dots using a pseudopotential approach. Our findings showed that the predicted nano-structured direct band gap is significantly increased relative to the bulk one. For a nanocrystal diameter in the range 1.2-5 nm, the refractive index and dielectric constant
Mat. Res.. Publicado em: 30/05/2019
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2. Isolantes de porta com altas constantes dieletricas (High K) para tecnologia MOS / High K gate insulators for MOS technology
High k insulators for the next generation (sub-32 nm CMOS (complementary metaloxide-semiconductor) technology), such as titanium oxide (TiOx), titanium oxynitride (TiOxNy), titanium-aluminum oxynitride (AlxTiwOyNz), titanium-aluminum nitride (AlxTiwNz) and titanium-aluminum oxide (AlxTiwOy), have been obtained by Ti or Ti/Al e-beam evaporation, with addition
Publicado em: 2008
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3. Caracterização óptica de dispersões aquosas de nanotubos de carbono
It has been demonstrated that the electronic and optical properties of single-wall carbon nanotubes (SWNT) are strongly affected by the environment. This strong environmental effect is very relevant in analyzing the composition of carbon nanotube samples using optical techniques, especially in the case of separation experiments, where the SWNT environments a
Publicado em: 2008
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4. Photothermal methodology applied in the characterization of pasty materials / Metodologia fototermica aplicada na caracterização de materiais pastosos
Neste trabalho desenvolveu-se um experimento de detecção fototémica com dois sensores piroelétricos em uma célula capacitiva que permite a realização de medidas térmicas e elétricas em materiais pastosos em função da temperatura.A célula idealizada para medidas elétricas e térmicas é um capacitor plano de placas paralelas capaz de obter das am
Publicado em: 2008
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5. Synthesis and characterization of bismuth zinc niobate pyrochlore nanopowders
Bismuth zinc niobate pyrochlores Bi1.5ZnNb1.5O7 (alpha-BZN), and Bi2(Zn1/3Nb2/3)2O 7 (beta-BZN) have been synthesized by chemical method based on the polymeric precursors. The pyrochlore phase was investigated by differential scanning calorimetry, infrared spectroscopy, and X ray diffraction. Powder and sintered pellets morphology was examined by scanning el
Materials Research. Publicado em: 2007-09
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6. Synthesis and dielectric properties of the lase sintered Ba1-xCaxTiO3 (0 ≤ x ≤ 0.30) nanostructured ceramics / Síntese e propriedades dielétricas de cerâmicas nanoestruturadas de Ba1xCaxTiO3 (0 menor igual x menor igual 0.30) sinterizadas a laser
Ba1-xCaxTiO3 (0 ≤ x ≤ 0.30) nanocrystalline powders were successfully synthesized for the first time at relative low temperature (500 °C) by a modified polymeric precursor method. The densification of the ceramics was made by two distinct techniques: conventional sintering using an electric furnace; and by a laser sintering process in which a CO
Publicado em: 2006
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7. Test of Anderson-Stuart model and the "universal" conductivity in rubidium and cesium silicate glasses
An analysis and brief discussion of experimental ionic conductivity sigma and activation energy E A in the binary rubidium and cesium silicate systems is presented, exemplified on 23 and 30 glasses respectively, in a wide composition range (5-45 Rb2O and Cs2O mole%). The Anderson and Stuart model has been considered to describe the variation of activation en
Brazilian Journal of Physics. Publicado em: 2005-09
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8. Flutuações de composição em um elastomero dieletrico processado por extrusão
Dielectric polymer materials, such as the elastomers based on poly(ethylene/propylene/1,4-hexadiene), also called EPDM or ethylene-propylene rubbers, are normally used for the electric insulation of hiqh voltage cables. The dielectric strength of these materiaIs is one of the most significant properties for the evaluation of their performance, as a function
Publicado em: 1988
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9. The dielectric properties of water within model transbilayer pores.
Ion channels contain extended columns of water molecules within their transbilayer pores. The dynamic properties of such intrapore water have been shown to differ from those of water in its bulk state. In previous molecular dynamics simulations of two classes of model pore (parallel bundles of Ala20 alpha-helices and antiparallel barrels of Ala10 beta-strand
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10. Gaussian fluctuations and linear response in an electron transfer protein
In response to charge separation or transfer, polar liquids respond in a simple linear fashion. A similar linear response for proteins might be expected from the central limit theorem and is postulated in widely used theories of protein electrostatics, including the Marcus electron transfer theory and dielectric continuum theories. Although these theories ar
The National Academy of Sciences.
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11. Physical reasons for the unusual α-helix stabilization afforded by charged or neutral polar residues in alanine-rich peptides
We have carried out conformational energy calculations on alanine-based copolymers with the sequence Ac-AAAAAXAAAA-NH2 in water, where X stands for lysine or glutamine, to identify the underlying source of stability of alanine-based polypeptides containing charged or highly soluble polar residues in the absence of charge–charge interactions. The resul
The National Academy of Sciences.
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12. Water in channel-like cavities: structure and dynamics.
Ion channels contain narrow columns of water molecules. It is of interest to compare the structure and dynamics of such intrapore water with those of the bulk solvent. Molecular dynamics simulations of modified TIP3P water molecules confined within channel-like cavities have been performed and the orientation and dynamics of the water molecules analyzed. Cha