Navegando por Assunto "Nanotubo de carbono"

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Acesso aberto (Open Access)
Dinâmica molecular de armazenamento de H2 em nanotubos de carbono sob ação de campo elétrico externo
(Universidade Federal do Pará, 2016-01-27) AIRES, Júlio Cesar Nunes; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
Several thermodynamic properties were analyzed through computer simulations systems, in which we used a carbon nanotube a gas molecule (H2), the very low initial temperature of 10-3K order. This H2 molecule was chosen because of its properties are of great application in different branches of study, the physical sciences, chemical and biological. The H2 molecule is individually relaxed inside and outside the nanotube during simulations. Each system was under the influence of a uniform electric field parallel to the carbon nanotube and the thermal effect on the initial temperature in the simulations generating the evanescent effect. Due to the electric field, the molecule rotates at a low temperature in orbit about the carbon nanotube while increasing the value of the electric field permitted the variation of the radius of the orbit atoms. The calculated amounts were the following: kinetic energy, potential energy, the total energy, temperature variation in situ, the molar entropy and the mean radius of the orbit atoms. The data suggest the action of the electric field is sufficient only to generate the evanescent attractive potential and this system can be used as a sensor selector atoms.
Acesso aberto (Open Access)
Propriedades elétricas de nanoantena de grafeno
(Universidade Federal do Pará, 2015-02-24) TAVARES, Simone Cristina da Costa; DEL NERO, Jordan; http://lattes.cnpq.br/5168545718455899
The incessant rush for discovering new materials and the search for new solutions to the tech-nological problems and equipment that have devices with better performance than the currently available, operating at ever smaller scales led us to study antennas that allow to occupy an increasingly small space. This permitted us to show the study of the electronic carbon nanotube structure and the electrical properties of graphenenano-antenna as its precursors. The develop-ment of antennas made of carbon nanotube and graphene is, in the moment, a technological possibility opened to state of art. In this paper we investigate the electronic transport for gra-phene organic material using it as a nano-antenna where we present simulations of quantum calculations derived from Hartree-Fock theory and semi-empirical method, which is given by the electron charge distribution along the structure. The structural parameters of the optimized structure have been fully calculated, including external electric field across the matrix layer of closed Roothaan-Hall model. Featuring a characteristic related to the electrical response which results a transistor device field effect, with capacitance and operating frequency in 90 THz un-der an operating voltage around the 0,82 V rectification and we show, also, the Fowler-Nord-heim model and Millikan -Lauritsen for graphene structure.