Listar Física por título
Mostrando ítems 1-20 de 28
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A thermodynamic cycle for the solar cell
(2017-01-06)A solar cell is a heat engine, but textbook treatments are not wholly satisfactory from a thermodynamic standpoint, since they present solar cells as directly converting the energy of light into electricity, and the current ... -
Los albores de la física y el desarrollo de la meteorología en Costa Rica
(2002)El siguiente artículo describe algunos aspectos del desarrollo de la física en Costa Rica, con énfasis en el siglo XIX. El trabajo está basado en una investigación bibliográfica de fuentes históricas, donde se compilaron ... -
Algunas ideas para lograr un mayor desarrollo científico y tecnológico en Costa Rica
(2000)El propósito de este capítulo, el cual está basado en el trabajo de Fernández y Páez (2000), es describir las actividades en Ciencias Espaciales que se están llevando a cabo en Costa Rica, estas actividades están centradas ... -
Chandler wobble: Stochastic and deterministic dynamics
(2016-09-18)We propose a model of the Earth’s torqueless precession, the “Chandler wobble,” as a self-oscillation driven by positive feedback between the wobble and the centrifugal deformation of the portion of the Earth’s mass contained ... -
Design and Characterization of a High Vacuum Metals Deposition System based on Electron Beam Evaporation
(2010-08-03)We describe a high vacuum metals deposition system based ona variation of a pendant-drop type electron beam evaporator.This system uses a Molybdenum crucible as an evaporantinstead of a rod or wire usually used in ultrathin ... -
Diseño y caracterización de un enfriador de átomos de tipo “desacelerador Zeeman”
(2016)Nosotros presentamos un método que utiliza simultáneamente dos modelos matemáticos, con el objetivo de optimizar el diseño de un desacelerador Zeeman, con miras a la implementación de átomos ultrafríos a la física del ... -
Distribución espacial de impactos de eventos hidrometeorológicos en América Central
(2016)América Central está expuesta a la ocurrencia de eventos hidrometeorológicos a lo largo del año y los impactos que estos pueden provocar van a estar mayormente localizados en áreas donde las variables tanto naturales como ... -
El inflatón complejo
(1999) -
El inflatón complejo
(1999) -
Electronic structure of silicon-based nanostructures
(2007-08-30)We have developed a unifying tight-binding Hamiltonian that can account for the electronic properties of recently proposed Si-based nanostructures, namely, Si graphene-like sheets and Si nanotubes. We considered the sp3s∗ ... -
Estimation of Silicon Nanocrystalline Sizes from Photoluminescence Measurements of RF Co-Sputtered Si/SiO2 Films
(Materials Research Society Symposium Proceedings 737 (2003), 2003)A stochastic distribution of nanocrystalline sizes model is applied to fit photoluminescence (PL) spectra of luminescent Si nanocrystals in a Si/SiO2 matrix synthesized by RF co-sputtering on the top of quartz substrates. ... -
Irreversibility in an ideal fluid
(2014-10)When a real fluid is expelled quickly from a tube, it forms a jet separated from the surrounding fluid by a thin, turbulent layer. On the other hand, when the same fluid is sucked into the tube, it comes in from all ... -
Landau theory and giant room-temperature barocaloric effect
(2017-10-17)The structural phase transitions of MF3 (M = Al, Cr, V, Fe, Ti, Sc) metal trifluorides are studied within a simple Landau theory consisting of tilts of rigid MF6 octahedra associated with soft antiferrodistortive optic ... -
Large isotropic negative thermal expansion above a structural quantum phase transition
(2015-10-01)Perovskite structured materials contain myriad tunable ordered phases of electronic and magnetic origin with proven technological importance and strong promise for a variety of energy solutions. An always-contributing ... -
Negative thermal expansion near two structural quantum phase transitions Connor
(2017-12-18)Recent experimental work has revealed that the unusually strong, isotropic structural negative thermal expansion in cubic perovskite ionic insulator ScF3 occurs in excited states above a ground state tuned very near a ... -
Random Electric Field Instabilities of Relaxor Ferroelectrics
(2017-06-13)Relaxor ferroelectrics are complex oxide materials which are rather unique to study the effects of compositional disorder on phase transitions. Here, we study the effects of quenched cubic random electric fields on the ... -
Stochastic approach to the smart quantum confinement model in porous silicon
(Surface Science 515 (2002) L509-L513, 2002)A model that encompasses two approaches to explain the photoluminescence in p-type porous silicon is proposed. The model considers a stochastic distribution of nanocrystallite sizes within the porous matrix and explain the ...