Hopping Mechanism
Mostrando 1-12 de 23 artigos, teses e dissertações.
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1. Analysis of dielectric and electrical transport properties of NdFeAsO ceramic
Abstract The iron-based ceramic NdFeAsO was synthesized by the solid-state reaction method. The tetragonal crystal structure was confirmed at room temperature through the X-ray diffraction technique. The dielectric characteristics i.e. dielectric constant (εr) and loss tangent (tanδ) of the sample were studied at a wide range of temperature and frequencies
Cerâmica. Publicado em: 2022
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2. Ferrimagnetic to paramagnetic transition and dielectric relaxation in Ni1-xZnxFe2O4 ferrites
Abstract The spinel ferrite system Ni1-xZnxFe2O4 (x=0-0.7, Δx=0.1) was prepared by wet chemical co-precipitation method using sulfates of respective metal ions. The electrical resistivity and dielectric properties of the prepared samples have been studied as a function of temperature, frequency, and Zn content (x). The DC resistivity (ϱ) was measured in th
Cerâmica. Publicado em: 2021-06
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3. Transport Properties of Polycrystalline Mixed Copper-Zinc Ferrites
Polycrystalline mixed Cu-Zn spinel ferrites with general formula Cu1-xZnxFe2O4 (x = 0.0, 0.1, 0.3, 0.5 and 0.7) have been prepared by solid-state reaction method. The effect of Zn2+ ions on transport properties such as DC and AC resistivity, dielectric constant and dielectric loss tangent has been presented in this paper. The resistivity increases with Zn co
Mat. Res.. Publicado em: 19/04/2018
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4. CARACTERIZAÇÃO DE NANOFIOS DE GERMÂNIO SINTETIZADOS UTILIZANDO COBRE COMO CATALISADOR
This paper presents reliable synthesis of germanium nanowires by the vapor-liquid-solid method using copper as an alternative catalyst to gold, the most commonly used metal. The morphological study showed long range single-crystalline germanium nanowires with diamond structure and diameters ranging from 20 nm to 80 nm and lengths in tenths of a micrometer
Quím. Nova. Publicado em: 2015-07
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5. Fabricação e caracterização de dispositivos baseados em nanofitas de Óxido de Estanho (SnO2)
The structural and transport features of tin oxide nanobelts synthesized by the vapor-solid method combined with the carbothermal reduction process were investigated in this work. The samples synthesized were characterized by using experimental techniques such as scanning and transmission electron microscopy and x-ray diffraction. The nanobelts were found to
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/08/2012
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6. Transporte eletrônico e propriedades termodinâmicas de nanobiomoléculas
Nesta tese, investigamos a transmissividade e as características de corrente como função da diferença de potencial, no contexto da ligação forte, em seqüências de dupla fita do DNA. Com o intuito de investigar a relevância das correlações subjacentes nas distribuições dos nucleotídeos, comparamos os resultados de uma seqüência genômica do DN
Publicado em: 2009
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7. MECHANISM STUDY OF THE PN AND NS FORMATION IN THE INTERSTELLAR, COMETARY AND PLANETARY MEDIUM / ESTUDO DOS MECANISMOS DE FORMAÇÃO DAS ESPÉCIES PN E NS NO MEIO INTERESTELAR, EM COMETAS E ATMOSFERAS PLANETÁRIAS
This study investigates the chemical mechanisms of PN and NS formations in the interstellar medium, comets and the atmosphere of giant planets such as Saturn and Jupiter. The quantum chemical calculations were performed by using the CCSD and CCSD(T) levels of theory. The basis sets used in this study were 6- 311++G(d,p) and 6-311++G(3df,3pd). Geometry optimi
Publicado em: 2009
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8. Análise funcional e histológica da utilização da hialuronidase durante a anestesia local em nervo ciático de ratos / Functional and histological analysis of hyaluronidase use during local anesthesia of the rat sciatic nerve
The concomitant use of the enzyme hyaluronidase (H) and local anesthetics (LA) is widely employed in ophthalmology in order to improve the effectiveness of anesthesia; in dentistry, however, this association did not seem advantageous. A new protocol was tested with the aim of drawing out local anesthesia without supplementary anesthesia. This possibility is
Publicado em: 2008
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9. Propriedades elétricas e físico-químicos de blendas de poli (sulfeto de p-fenileno) - pps com um cristal líquido polimérico (LCP) / Electrical and physical chemistry properties of poli (p-phenylene sulfide) with a liquid crystal polymer
Poly (p-phenylene sulphide) (PPS) is an engineering thermoplastic, with high thermal and chemical resistance, and. with a growing industrial importance, due to its easy processability in the form of films, fiaments and injection molded articles. It also can be chemically doped and. therefore be a conductive polymer (σ = 10 S/cm, by doping with AsF5); ho
Publicado em: 1997
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10. Propriedades eletroquimicas de hexacianoferratos absorvidos pela silica gel quimicamente modificada com oxido de Zr(IV)
Silica gel with a specific surface area of 424 m.g and an average pore diameter of 6 nm, was coated with Zr(IV) oxide by reacting ZrCl4 or ZrOCl2 with SiO2. The amount of Zr(IV) grafted on SiO2, hereafter denoted as SZrOH, was 470 mmol.g and 250 mol.g using respectively, ZrCl4 and ZrOCI2. The hexacyanoferrate(ll) complex (HCF) was adsorbed by SZrOH in acid s
Publicado em: 1994
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11. Nuclear magnetic resonance in superionics conductors with fluorite-type structure. / Ressonância magnética nuclear em condutores superiônicos de estrutura fluorita.
The 19F NMR relaxation times T1 and T2 were measured is ternary and nonstoichiometric compounds with the fluorite-type structure. We have studied the Na0.4Y0.6F2.2 crystal in the temperature range 600K to 900K, where the crystal hás not the fluorite structure. The T1 values were measured in two Larmor frequencies: 20.42 MHz and 34.24 MHz. The results for T1
Publicado em: 1990
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12. tRNA hopping: enhancement by an expanded anticodon.
At a low level wild-type tRNA(1Val) inserts a single amino acid (valine) for the five nucleotide sequence GUGUA which has overlapping valine codons. Mutants of tRNA(1Val) with an insertion of A or U between positions 34 and 35 of their anticodons have enhanced reading of the quintuplet sequences. We propose that this decoding occurs by a hopping mechanism ra