Navegando por Assunto "Evanescence effect"

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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)
Sensores de narcóticos, gás natural e syngás utilizando nanotubos de carbono sob ação de campo elétrico externo
(Universidade Federal do Pará, 2021-02-15) AIRES, Júlio Cesar Nunes; CHAVES NETO, Antonio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
This work presents an analysis of the molecular dynamics between several illicit drugs: benzoylmethylecgonine, diacetylmorphine, 3,4 methylenedioxymethamphetamine, D-Deoxefedrine, lysergic acid diethylamide and, interacting with a section of carbon nanotubes at low initial temperature, corresponding to 10-3 K, and under a uniform electric field, like a drug detection system. In addition to the analysis of the behavior of natural gas molecules and SYNGAS interacting with a carbon nanotube at an initial simulation temperature of 300K, with all systems being relaxed by 50 ps outside the carbon nanotube, describing each possible arrangement for capture; a constant external electric field was then applied to the systems, longitudinally, along the length of the carbon nanotube, promoting an evanescent effect, capable of trapping them orbiting the carbon nanotube. Simulations for electric field intensities within a range of 10-5 to 10-1 a.u. were performed, to verify the behavior of drugs, while for the molecules that comprise Natural Gas and SYNGAS, a range of 10-8 to 10-1 a.u. was adopted. Average orbital radii were estimated, in addition to a number of thermodynamic properties. Our results indicate that the combination of a uniform external electric field and van der Waals interactions in a carbon-derived nanotube is enough to create an evanescent field of attractive potential, modeling it as a system for the detection of temperature and drug rays .