Wednesday, October 22, 2014

 

 



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rss_1.0 Clasificación por Disciplina

Nomenclatura Unesco > (22) Física > (2203) Electrónica
(2203.01) Circuitos (2203.02) Elementos de circuitos
(2203.03) Válvulas electrónicas (2203.04) Microscopía electrónica
(2203.05) Estados electrónicos (2203.06) Transporte de electrones
(2203.07) Circuitos integrados (2203.08) Fotoelectricidad
(2203.09) Piezoelectricidad (2203.99) Otras (especificar)

Categorías relacionadas:
(3307) Tecnología electrónica

Mostrando recursos 1 - 20 de 239,898

1. Emisiones de los cigarrillos electrónicos y su posible impacto sobre la salud - Cremades Oliver, Lázaro Vicente
El cigarrillo electrónico (e-cigarrillo) se introdujo en el mercado de los EEUU en 2007 como una alternativa menos perjudicial para la salud que el consumo de tabaco. Externamente los e-cigarrillos tienen el aspecto de cigarrillos normales, pero internamente son muy diferentes: no contienen tabaco. Disponen de un mecanismo que calienta la nicotina líquida, que se convierte en un vapor que los fumadores inhalan y exhalan. Los fabricantes y los clientes satisfechos dicen que este vapor ofrece muchas ventajas sobre el humo del cigarrillo tradicional. Sin embargo, las agencias reguladoras y algunos expertos en salud no están tan seguros. Se está...

2. Diseño y construccion de un torno de control numérico. - Londoño Ospina, Nelson; León Simanca, Pedro; Alvarez Díaz, Jairo; Marín Zapata, Edwin
Next we talk about the design; implementation and results of a numerical control system, and the electronic system are explained. With further detail it is explored the Software used to make chess pieces, based on a drawing created with any graphic design Software. Additionaly, we describe basic algorithm and concepts refering to the conversion into displacement units of the actuator of the system, besides of the graphic interface that facilitates the inter-relation between the user (designer) and the CAD system.

3. La contratación administrativa utilizando medios electrónicos y telemáticos - Palomar Olmeda, Alberto

4. Módulo de un sistema de inyección electrónico de gasolina basado en el microcontrolador intel 8751 3. - Romero Piedrahita, Carlos Alberto; Márquez C., Jhon Fredy; Orozco G., Jorge Mario
In this article there are described the steps followed in the design of a functional and representative fuel injection system, based on the knowledge of the values of important parameters sensed and handled at the process, such as: throttle position sensor (TPS), manifold absolute pressure (MAP), crankshaft speed (RPM), and water coolant temperature (Tenf). The importance of microcontroller is highlighted as the means for controlling, and the tasks performed by each one of the 3 microcontrollers are defined.

5. Design of elliptic curve cryptoprocessors over GF(2^163) using the Gaussian normal basis - Realpe, Paulo Cesar; Trujillo-Olaya, Vladimir; Velasco Medina, Jaime
This paper presents the efficient hardware implementation of cryptoprocessors that carry out the scalar multiplication kP over finite field GF(2163) using two digit-level multipliers. The finite field arithmetic operations were implemented using Gaussian normal basis (GNB) representation, and the scalar multiplication kP was implemented using Lopez-Dahab algorithm, 2-NAF halve-and-add algorithm and w-tNAF method for Koblitz curves. The processors were designed using VHDL description, synthesized on the Stratix-IV FPGA using Quartus II 12.0 and verified using SignalTAP II and Matlab. The simulation results show that the cryptoprocessors present a very good performance to carry out the scalar multiplication kP. In this...

6. Energy level alignment for many-body resonant tunneling - Walkenhorst, Jessica; Appel, H.; Helbig, N.; Rubio, Angel
Electron tunneling plays a fundamental role in many chemical and physical processes, whilst electron tunneling at surfaces also attracts much attention due to its importance for charge transfer and carrier injection mechanisms e.g. in organic devices. Resonant tunneling is governed by the alignment of energy levels of donor and acceptor. While the separate systems are described well by standard approaches, the alignment of their chemical potentials is problematic since bringing donor and acceptor in contact changes the respective energy levels due to the electronic interaction. We investigate resonant many-body tunneling in a one dimensional donor-acceptor system, where the electrons interact via a...

7. Non-adiabatic molecular dynamics with conditional wave functions - Albareda, Guillermo; Appel, H.; Franco, Ignacio; Abedi, Ali; Rubio, Angel
A rigorous trajectory-based approach to treat the coupled electronnuclear motion in terms of conditional wave functions is presented. By projecting the Schrödinger equation on the actual configuration of an infinite set of nuclear trajectories, an ensemble of conditional electronic equations of motion is obtained. These equations do not rely on any tracing-out of degrees of freedom and their propagation does not require a prior knowledge of the involved potential-energy surfaces. Using an exact factorization of the full molecular wave function, we establish a formal connection with the recently proposed exact potential energy surfaces. This connection is used to gain insight from a simplified propagation...

8. Optimized e ective potential approach to time-dependent density functional theory for many-electron systems inter- acting with cavity photons - Pellegrini, Camilla; Flick, Johannes; Appel, H.; Tokatly, I. V.; Rubio, Angel
In a recent paper time dependent density functional theory has been generalized to many-electron systems strongly coupled to quantum electromagnetic modes of a microcavity. Here we construct an approximation for the corresponding exchange-correlation (xc) potential by extending the optimized effective potential (OEP) method to the electron-photon system. The derivation of the OEP equation employing the non-equilibrium Green's function formalism, and the first order approximation for the electronic self-energy is presented. Beyond the mean field level, the electron-photon coupling generates a time non-local photon-mediated interaction between the electrons, whose propagator enters the exchange-like diagram. We further show the approximated xc-potential for a model two-level...

9. Correlated light-matter interactions in cavity QED - Flick, Johannes; Appel, H.; Rubio, Angel
In the electronic structure community, the quantized nature of the electrons is usually (approximately) incorporated, whereas the electromagnetic field is mostly treated classically. In contrast, in quantum optics, matter is typically simplified to models with a few levels, while the quantized nature of light is fully explored. In this work, we aim at treating both, matter and light, on an equal quantized footing. We present exact solutions for fully quantized prototype systems consisting of atoms or molecules placed in optical one- and twodimensional high-Q cavities and coupled to the quantized electromagnetic modes in the dipole or quadrupole coupling regime. We focus on spontaneous...

10. Model of √3x√3 phases of silicene and its multilayers - Cahangirov, Seymur; Ongun, V.; Özçelik; Ciraci, Salim; Asensio, María C.; Rubio, Angel
Silicene, a monolayer of silicon atoms arranged in a honeycomb structure, received an enormous interest for being a candidate two-dimensional material that could bring the exotic electronic structure of graphene to the well-developed silicon-based technology. Experiments have shown that silicene synthesized on Ag substrates can acquire various reconstructions. In particular, structures having √3x√3 reconstruction have been frequently observed but yet poorly understood. Here we provide a compelling high-resolution angle resolved photoemission (ARPES) study together with first-principles calculations and scanning tunneling microscopy (STM), which unambiguously prove the existence of a particular two-dimensional arrangement of silicon atoms that, gives rise to two...

11. Ultrafast charge generation in a photoexcited polymer-fullerene blend: insights from real-time TDDFT - Rozzi, Carlo Andrea; Amato, M.; Rubio, Angel; Molinari, Elisa
The initial quantum dynamics leading to electron transfer from the photoexcited polymer to the fullerene in P3HT-PCBM is investigated ab-initio by time-dependent density functional theory simulations. We find coherent electron transfer between donor and acceptor and oscillations of the transferred charge with a period matching that of observed vibrational modes in ultrafast optical spectroscopy. Our results show that the coherent coupling between electronic and nuclear degrees of freedom is of key importance in triggering charge delocalization and transfer not only in covalently bonded molecules but also in this prototype non-covalently bonded system of relevance for photovoltaics.

12. Prediction of new 2D materials: after graphene and silicene, now a hint of germanene synthesis - Dávila, M. E.; Xian, Lede; Cahangirov, Seymur; Rubio, Angel; Le Lay, Guy
Theoretical calculations by Kyozaburo Takeda and Kenji Shiraishi predicted 20 years ago the possible existence and properties of 2D- new materials, later called : graphene, silicene and germanene. For the experimental discovery of graphene in 2004, Andrei Geim and Konstantin Novoselov were awarded the Nobel Prize in Physics; since then, many experiments by the international community developed different forms of preparation and isolation of this material and their use in nanoelectronic devices. Later, the discovery of silicene by a team of researchers from Germany, Italy and France, with Drs Patrick Vogt, Paola de Padova and Prof. Guy Le Lay occured...

13. A TDDFT-based study on the proton-DNA interaction - Bernal, Mario A.; Brunetto, Gustavo; Seraide, Rodrigo; Giovannini, U. de; Rubio, Angel
The interaction of ionizing particles with DNA induces damage in this molecule. This damage may lead to biological effects, as for instance carcinogenesis. The use of heavy charged particles for radiation therapy is growing very fast due to their dosimetric and radiobiological advantages. However, the mechanisms at the atomic level involved in the early stage of this damage are not well understood yet. In this work we present a study on the proton-DNA collision using the Time-Dependent Density Functional Theory (TD-DFT). An isolated DNA nucleotide pair is targeted by a swift proton, with initial kinetic energy of about 4 keV....

14. Time-dependent density functional theory for many-electron systems interacting with photons: tddft for cavity-qed - Tokatly, I. V.
Experimental progress in the fields of cavity and circuit quantum electrodynamics (QED) opens a possibility to study many-electron systems strongly interacting with quantum light. Obviously, the classical treatment of external fields prevents application of the standard TDDFT to this new class of problems. Here I present a generalization of TDDFT for many-electron systems strongly coupled to quantum electromagnetic modes of a microcavity. I show that the full electron-photon wave function is a unique functional of the electronic (current) density and the expectation values of photonic coordinates. The Kohn-Sham system is constructed, which allows to calculate the above basic variables by...

15. Las infracciones de derechos de propiedad intelectual sobre bases de datos electrónicas internacionales de encuentros deportivos - García Mirete, Carmen María
El trabajo analiza las infracciones sobre bases de datos electrónicas que contienen información de encuentros deportivos en la medida en que plantean problemas de Derecho internacional privado. Estas bases de datos son puestas a disposición del público en Internet, circunstancia que tiene dos efectos: por una parte, es relativamente sencillo vulnerar los derechos de los titulares de estas bases de datos; por otra, cuando se producen, estos actos ilegítimos suelen ser infracciones internacionales. Esta coyuntura implica la necesidad de clarificar, en primer lugar, la protección jurídica de las bases de datos electrónicas que incluyen información sobre eventos deportivos; en segundo...

16. Indicadores de calidad de la Biblioteca Universitaria. Evolución 2010-2013 - Biblioteca Universitaria
Entre las objetivos del el Plan Estratégico de la Biblioteca Universitaria 2008-2011 se recogía el establecimiento de un conjunto de indicadores de calidad de la Biblioteca Universitaria, que fueron aprobados en Comisión SIBID, con fecha 12-11-2008 y modificados en dicha Comisión con fecha 27-02-2009). Para la elaboración de los indicadores nos basamos en las normas UNE-ISO 50137:2000, 1ª modificación de junio de 2005 Indicadores de rendimiento bibliotecario y en UNE-ISO/TR 20983 IN de julio de 2006, Indicadores para los servicios bibliotecarios electrónicos. Este conjunto de indicadores nos permiten hacer un seguimiento periódico de los procesos, actividades y servicios principales llevados...

17. El lugar en el que se produce la reutilización de una bases de datos electrónica en Internet: el caso Football Dataco vs. Sportradar - García Mirete, Carmen María
Este trabajo analiza la infracción del derecho sui generis sobre las bases de datos electrónicas en Internet, en particular las cuestiones estudiadas en el asunto Football Dataco vs. Sportradar. En este caso el Tribunal de Justicia de la Unión Europea examina si el envío de información de una base de datos protegida al territorio de otro Estado miembro constituye un acto de reutilización y el lugar en el que se produce dicho acto. La localización del acto de reutilización de la información obtenida de una base de datos protegida por un derecho sui generis es imprescindible para poder designar el...

18. Performance assessment of an architecture with adaptative interfaces for people with special needs - Gómez Martínez, María Elena; González Cabero, Rafael; Merseguer Ruiz, José
People in industrial societies carry more and more portable electronic devices (e.g., smartphone or console) with some kind of wireles connectivity support. Interaction with auto-discovered target devices present in the environment (e.g., the air conditioning of a hotel) is not so easy since devices may provide inaccessible user interfaces (e.g., in a foreign language that the user cannot understand). Scalability for multiple concurrent users and response times are still problems in this domain. In this paper, we assess an interoperable architecture, which enables interaction between people with some kind of special need and their environment. The assessment, based on performance patterns and...

19. Experimental analysis of a photovoltaic concentrator based on a single reflective stage immersed in an optical fluid - Victoria Pérez, Marta; Domínguez Domínguez, César; Askins, Stephen; Anton Hernandez, Ignacio; Sala Pano, Gabriel
This article reviews all the experimental tests carried out to analyze the performance of a FluidReflex photovoltaic concentrator. This novel concentrator concept consists of a single reflective stage immersed in an optical fluid. The presence of the fluid entails significant advantages. It not only allows a high system optical efficiency and increases the attainable concentration but also enhances the heat dissipation from the cell. In addition, the electrical insulation is improved, and the problem of water vapor condensation inside the module is avoided. A complete characterization is addressed in this paper. Among the experimental results, a measured optical efficiency of...

20. Durability of dielectric fluids for concentrating photovoltaic systems - Victoria Pérez, Marta; Askins, Stephen; Domínguez Domínguez, César; Anton Hernandez, Ignacio; Sala Pano, Gabriel
Several dielectric fluids that might be used for immersing optics are analyzed in this paper. Their transmittances, both before and after an accelerated exposure to ultraviolet (UV) radiation equivalent to several years under real sun, are presented. In addition, the photocurrent losses caused by the decrease in transmittance experienced by each fluid are estimated for current III?V multijunction (MJ) solar cells. The most stable fluids were found to be paraffin and silicone oils whose transmittances remained practically unaltered after a UV dosage equivalent to 3 years of AM1.5D radiation.

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