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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 171.111

1. Bandwidth-length trade-off figures of merit for electro-optic traveling wave modulators - Ibarra Fuste, Jose Antonio; Santos Blanco, M. Concepción
Closed-form expressions explicitly relating modulation bandwidth and active length in electro-optic traveling wave modulators are presented which fully account for skin-effect electrode loss and optical-electrical wave velocities mismatch. Four operative margins have been identified where the bandwidth–length trade-off figure of merit takes simple forms.

2. Computationally efficient real-time digital predistortion architectures for envelope tracking power amplifiers - Gilabert Pinal, Pere Lluís; Montoro López, Gabriel
This paper presents and discusses two possible real-time digital predistortion (DPD) architectures suitable for envelope tracking (ET) power amplifiers (PAs) oriented at a final computationally efficient implementation in a field programmable gate array (FPGA) device. In ET systems, by using a shaping function is possible to modulate the supply voltage according to different criteria. One possibility is to use slower versions of the original RF signal’s envelope in order to relax the slew-rate (SR) and bandwidth (BW) requirements of the envelope amplifier (EA) or drain modulator. The nonlinear distortion that arises when performing ET with a supply voltage signal that follows both the original and...

3. Elliptical arguments: a problem in relating meaning to use - Hanks, Patrick
Corpus lexicographers working in the tradition of John Sinclair (of whom the present author is one) argue that electronic dictionaries of the future will have a duty to pay close attention to phraseology and to phraseological meaning in text. To do this, they will need to make a distinction between normal patterns of use of words and exploitations of normal uses, such as freshly coined metaphors, used for rhetorical and other effects. Electronic dictionaries will report the norms of phraseology associated wilh phraseological patterns instead of or as well as word meaning in isolation. The foundations for this approach to...

4. Localized IR communications with Thymio II - Soldevila Vilarrasa, Josep
[ANGLÈS] The goal of this master project is to develop an IR communication protocol for the robot Thymio II in order to use the seven IR proximity sensors existing in the robot, used to detect obstacles around it) to exchange data between several of them. We must achieve this goal with the current electronic design, so we can not add or change any hardware of the robot. The protocol must fulfil the following characteristics: • Exchange 8 bits of data and some bits of header per frame. • Transmit and receive data without disturbing the obstacle detection around the robot....

5. Tracking a Mobile Receiver using the Unscented Kalman Filter - Bordoy Andreu, Joan
[ANGLÈS] Indoor localization based on Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA) has been a promising subject of study the last years. In this thesis, a moving target is tracked by receiving discrete signals from stationary beacons. These beacons are assumed to be small and inexpensive and they require no further communication. Moreover, they emit short discrete signals at regular intervals and are assumed to be distinguished. The interval can be different for each sender and they do not need to start emitting at the same time instant, they can be unsynchronized. The algorithm used to...

6. Bandwidth-length trade-off figures of merit for electro-optic traveling wave modulators - Ibarra Fuste, Jose Antonio; Santos Blanco, M. Concepción
Closed-form expressions explicitly relating modulation bandwidth and active length in electro-optic traveling wave modulators are presented which fully account for skin-effect electrode loss and optical-electrical wave velocities mismatch. Four operative margins have been identified where the bandwidth–length trade-off figure of merit takes simple forms.

7. Computationally efficient real-time digital predistortion architectures for envelope tracking power amplifiers - Gilabert Pinal, Pere Lluís; Montoro López, Gabriel
This paper presents and discusses two possible real-time digital predistortion (DPD) architectures suitable for envelope tracking(ET) power amplifiers (PAs) oriented at a final computationally efficient implementation in a field programmable gatearray (FPGA) device. In ET systems, by using a shaping function is possible to modulate the supply voltage according to differentcriteria. One possibility is to use slower versions of the original RF signal’s envelope in order to relax the slew-rate (SR) andbandwidth (BW) requirements of the envelope amplifier (EA) or drain modulator. The nonlinear distortion that arises whenperforming ET with a supply voltage signal that follows both the original and...

8. Slabsim: Simulador de dispositivos ópticos integrados - Fernández González, Alberto
En los diseños y desarrollos de ingeniería, antes de comenzar la construcción e implementación de los objetivos de un proyecto, es necesario realizar una serie de análisis previos y simulaciones que corroboren las expectativas de la hipótesis inicial, con el fin de obtener una referencia empírica que satisfaga las condiciones de trabajo o funcionamiento de los objetivos de dicho proyecto. A menudo, los resultados que satisfacen las características deseadas se obtienen mediante la iteración de métodos de ensayo y error. Generalmente, éstos métodos utilizan el mismo procedimiento de análisis con la variación de una serie de parámetros que permiten adaptar una...

9. Ensayos acelerados de dispositivos electrónicos LED - Pedruelo Bragado, Jesús
El objetivo de este proyecto es el de determinar, a través de una serie de medidas, los tiempos de vida y causas de fallo de diodos LED. Para ello, se someterá a los dispositivos a condiciones extremas de temperatura y humedad dentro de una cámara climática, con el objetivo de acelerar su edad, su tiempo de uso, hecho que provocará la aparición de los fallos mucho antes que en condiciones normales de funcionamiento. Se tomarán medidas tanto de su tensión y corriente para el análisis de las gráficas I-V, dentro y fuera de la cámara, como de las potencias luminosas de cada...

10. A d^10 Ni–(H_2) Adduct as an Intermediate in H-H Oxidative Addition across a Ni-B Bond - Harman, W. Hill; Lin, Tzu-Pin; Peters, Jonas C.
Bifunctional E-H activation offers a promising approach for the design of two-electron-reduction catalysts with late first-row metals, such as Ni. To this end, we have been pursuing H_2 activation reactions at late-metal boratranes and herein describe a diphosphine–borane-supported Ni—(H_2) complex, [(^(Ph)DPB^(iPr))Ni(H_2)], which has been characterized in solution. ^1H NMR spectroscopy confirms the presence of an intact H_2 ligand. A range of data, including electronic-structure calculations, suggests a d^(10) configuration for [(^(Ph)DPB^(iPr))Ni(H_2)] as most appropriate. Such a configuration is highly unusual among transition-metal H_2 adducts. The nonclassical H_2 adduct is an intermediate in the complete activation of H_2 across the Ni-B...

11. A closed-loop IGBT non-destructive tester - Ahmed, Amr; Shadrokh, Y.; Coulbeck, L.; Castellazzi, A.; Johnson, C. M.
Non-destructive testing capability is a very important aspect of power device technology evolution towards more robust and reliable products. This paper proposes a closed-loop non-destructive tester for high power multi-chip IGBT modules. Other than proposed elsewhere in the past, the solution put forward here includes the possibility to be used in closed-loop, by proper identification and monitoring of representative pre-failure signatures to automatically trigger the activation of a protective switch and prevent the failure of the device under test. The advantage is that devices of different characteristics (e.g., voltage range, type) can be tested without having to set a specific...

12. Outcomes of electrically stimulated gracilis neosphincter surgery - Tillin, T; Chambers, M; Feldman, R
Objectives: To examine patient quality of life (QoL) and long-term costs of electrically stimulated gracilis neosphincter surgery (ESGNS). Design: Independently conducted prospective case-comparison study of patients at the Royal London Hospital (RLH), plus a cross-sectional study of outcomes of ESGNS performed at three other UK centres. Participants: Cases were patients who underwent ESGNS at the participating hospitals during a 5-year period from 1977. Comparisons were made with two groups of people with similar bowel disorders who did not undergo ESGNS. Intervention: ESGNS is a procedure designed to improve bowel function for people living with severe faecal incontinence or stomas. It...

13. Outcomes of electrically stimulated gracilis neosphincter surgery. - Tillin, T; Chambers, M; Feldman, R
To examine patient quality of life (QoL) and long-term costs of electrically stimulated gracilis neosphincter surgery (ESGNS). Independently conducted prospective case-comparison study of patients at the Royal London Hospital (RLH), plus a cross-sectional study of outcomes of ESGNS performed at three other UK centres. Cases were patients who underwent ESGNS at the participating hospitals during a 5-year period from 1977. Comparisons were made with two groups of people with similar bowel disorders who did not undergo ESGNS. ESGNS is a procedure designed to improve bowel function for people living with severe faecal incontinence or stomas. It involves transposition of the...

14. Non-Adiabatic Molecular Dynamics And Its Applications In Electron Transport In Nanostructures - Tong, L
Quantum Molecular dynamics (MD) simulations have been widely used to examine the dynamics of interactions between electrons and ions. The most commonly used MD method is the Born-Oppenheimer (BO) approximation, which assumes that the electronic states always stay on the ground-state energy surface of any given ionic configuration during the course of the simulation. The BO approximation, however, is not appropriate for studies of systems that are out of equilibrium, such as electron transport processes. One way of allowing an MD simulation to explore the non-equilibrium and excited states is to use the Ehrenfest approximation, which gives a full time-dependent...

15. Redes semánticas: herramienta para identificar lo que debe evaluarse en la docencia universitaria - Garza Quiñones, Rosa María
This paper shows the dimensions of teaching that should be integrated in a teacher´s evaluation instrument, as suggested by students and teachers of the Universidad Autonoma Agraria “Antonio Narro” (called UAAAN) in Saltillo, Coahuila, Mexico. An instrument thought for a semantic network was used and answered by BA students from 3rd, 5th, 7th, and 9th semesters and full time teachers. After six years of having employed an electronic system to evaluate specifically teaching functions at the UAAAN, the necessity to inquire among teachers and students about the elements that should have been included in the evaluation of teaching was observed....

16. Duvalius (Duvalius) lencinai Mateu & Ortuño, 2006 (Coleoptera, Carabidae, Trechini) una especie hipogea del sur de la península ibérica. Morfología, reubicación taxonómica, sistemática y biología - Ortuño, Vicente M.; Barranco Vega, Pablo
Duvalius (Duvalius) lencinai Mateu & Ortuño, 2006 (Coleoptera, Carabidae, Trechini) a hypogean species from the south of the Iberian peninsula. Morphology, new taxonomic placement, systematics and biology.- Duvalius (Duvalius) lencinai Mateu & Ortuño, 2006 was discovered in two new localities in the municipal district of Siles (Jaen, Spain): Sima Curva del Espino and Sima de los 30 Años, approximately 10 and 17 km, respectively, away from the type locality. The study of several individuals through dissection and use of optic and electronic microscopic preparations has increased the knowledge of the anatomy of this species. Evagination of the internal sac allowed...

17. Caracterización química y mineralógica de los materiales grises de los cuerpos Chinchorro modelados - Arriaza, Bernardo T.; Cornejo, Lorena; Lienqueo, Hugo; Standen, Vivien G.; Santoro, Calogero M.; Guerra, Nelson; Hoesen, John van; Santos, Mariela
This paper presents the chemical and mineralogical characterization of inorganic gray sediments used by the Chinchorro people to make their black mummies or reconstructed bodies. Thirteen samples taken from an inner layer of the black mummies (ca 4,000-2,800 BC) were studied to determine its mineralogical composition, plastic quality and whether it contained clay. The samples were analyzed at the Laboratorio de Investigaciones Medioambientales de Zonas Áridas, LIMZA (CIHDE-Universidad de Tarapacá), using energy dispersive X-ray fluorescence (EDXRF) and at the Laboratorio de Ciencias Geológicas de la Universidad del Norte, using X-ray diffraction and scanning electronic microscopy. In addition, experimental ceramic tests were undertaken at the Laboratorio de...

18. Basis Decomposition Discriminant ICA - Tabas Díaz, Alejandro
In this Master's Thesis, we introduce the methodology Basis-Decomposition Discriminant ICA(BD-DICA), capable of finding the most discriminant Independent Components to characterisea high-dimensional dataset. The algorithm provides for this characterisation for several componentswith the same structure as the inputs. An adaptation of the algorithm for FeatureExtraction is derived in the conclusions of this report.BD-DICA is constructed as a combination of the Basis-Decomposition ICA (BD-ICA), anarchitecture for ICA used in fMRI data analysis, and the Basis-Decomposition Fisher's LinearDiscriminant (BDFLD), a modified version of the classical FLD introduced in this work. BDDICAis originally designed to deal with fMRI Data analysis, in which often...

19. Tracking a Mobile Receiver using the Unscented Kalman Filter - Bordoy Andreu, Joan
[ANGLÈS] Indoor localization based on Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA) has been a promising subject of study the last years. In this thesis, a moving target is tracked by receiving discrete signals from stationary beacons. These beacons are assumed to be small and inexpensive and they require no further communication. Moreover, they emit short discrete signals at regular intervals and are assumed to be distinguished. The interval can be different for each sender and they do not need to start emitting at the same time instant, they can be unsynchronized. The algorithm used to...

20. El portafolios digital como herramienta para el desarrollo de competencias transversales en el alumnado. - Rodríguez Illera, J.L.; Galván, C.; Martínez Olmo, Francesc
Partiendo de un enfoque sobre las relaciones entre las tecnologías digitales como herramientas de mediación, se analiza el papel de un caso concreto, los portafolios electrónicos, para la mejora de competencias transversales en el ámbito universitario. Los resultados indican que se obtienen mejoras, como mínimo desde la percepción de los propios estudiantes, en algunas dimensiones ligadas a la capacidad para seleccionar y organizar información, así como a la planificación del aprendizaje.

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