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Examinando por Título

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0.13-µm CMOS tunable transconductor based on the body-driven gain boosting technique with application in Gm-C filters
(2011) Sánchez Rodríguez, Trinidad; González Carvajal, Ramón; Pennisi, Salvatore; Gómez Galán, Juan Antonio; Universidad de Sevilla. Departamento de Ingeniería Electrónica
We present a low-voltage low-power CMOS tunable transconductor exploiting body gain boosting to increase the small-signal output resistance. As a distinctive feature, the proposed scheme allows the OTA transconductance to be tuned via the current biasing the gain-boosting circuit. The proposed transconductor has been designed in a 0.13-µm CMOS technology and powered from a 1.2-V supply. To show a possible application, a 0.5-MHz tunable third order Chebyshev low pass filter suitable for the Ultra Low Power Bluetooth Standard has been designed. The filter simulations show that all the requirements of the chosen standard are met, with good performance in terms of linearity, noise and power consumption.
±0.25-V Class-AB CMOS Capacitance Multiplier and Precision Rectifiers
(IEEE (Institute of Electrical and Electronics Engineers), 2019) Pourashraf, Shirin; Ramírez Angulo, Jaime; Hinojo Montero, José María; González Carvajal, Ramón; López Martín, Antonio J.; Universidad de Sevilla. Departamento de Ingeniería Electrónica
Reduction of minimum supply requirements is a crucial aspect to decrease the power consumption in VLSI systems. A high-performance capacitance multiplier able to operate with supplies as low as ±0.25 V is presented. It is based on adaptively biased class-AB current mirrors which provide high current efficiency. Measurement results of a factor 11 capacitance multiplier fabricated in 180-nm CMOS technology verify theoretical claims. Moreover, low-voltage precision rectifiers based on the same class-AB current mirrors are designed and fabricated in the same CMOS process. They generate output currents over 100 times larger than the quiescent current. Both proposed circuits have 300-nW static power dissipation when operating with ±0.25-V supplies.
0.35-V SR-Enhanced Bulk-Driven OTA for Loads up to 10 nF
(IEEE, 2024-05-17) Ballo, Andrea; González Carvajal, Ramón; Grasso, Alfio Dario; Luján Martínez, Clara Isabel; Pennisi, Salvatore; Venezia, Chiara; Universidad de Sevilla. Departamento de Ingeniería Electrónica; European Union (NextGeneration EU); Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TIC-192: Ingeniería Electrónica
This study presents a low-voltage bulk-driven CMOS operational transconductance amplifier (OTA) operating in the subthreshold region designed to drive loads up to 10 nF, which is the largest value for this class of amplifiers. To meet this goal, the solution exploits the body terminal of various active devices leveraging local positive feedback to enhance the input transconductance gain and implementing dynamic threshold voltage control in the output transistors. This, along with a Slew Rate Enhancer section, significantly improves the OTA current driving capability. Experimental measurements conducted on a prototype, implemented in a 60-nm technology and supplied from 0.35 V, confirm the expected performance demonstrating a SR of 1.1 V/ms for a 10-nF load with a limited quiescent current consumption of 1.4 μ A.
±0.3V Bulk-Driven Fully Differential Buffer with High Figures of Merit
(MDPI, 2022-09) Gangineni, Manaswini; Ramírez Angulo, Jaime; Vázquez Leal, Héctor; Huerta Chua, Jesús; López Martín, Antonio J.; González Carvajal, Ramón; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. TIC192: Ingeniería Electrónica
A high performance bulk-driven rail-to-rail fully differential buffer operating from ±0.3V supplies in 180 nm CMOS technology is reported. It has a differential–difference input stage and common mode feedback circuits implemented with no-tail, high CMRR bulk-driven pseudo-differential cells. It operates in subthreshold, has infinite input impedance, low output impedance (1.4 kΩ), 86.77 dB DC open-loop gain, 172.91 kHz bandwidth and 0.684 μW static power dissipation with a 50-pF load capacitance. The buffer has power efficient class AB operation, a small signal figure of merit FOMSS = 12.69 MHzpFμW−1, a large signal figure of merit FOMLS = 34.89 (V/μs) pFμW−1, CMRR = 102 dB, PSRR+ = 109 dB, PSRR− = 100 dB, 1.1 μV/√Hz input noise spectral density, 0.3 mVrms input noise and 3.5 mV input DC offset voltage.
0/1-Polytopes related to Latin squares autotopisms
(2008) Falcón Ganfornina, Raúl Manuel; Universidad de Sevilla. Departamento de Matemática Aplicada I (ETSII)
The set LS(n) of Latin squares of order n can be represented in Rn3 as a (n−1)3-dimensional 0/1-polytope. Given an autotopism Θ=(α,β,γ)∈An, we study in this paper the 0/1-polytope related to the subset of LS(n) having Θ in their autotopism group. Specifically, we prove that this polyhedral structure is generated by a polytope in R((nα−l1α)⋅n2+l1α⋅nβ⋅n)(l1α⋅l1β⋅(n−l1γ)+l1α⋅l1γ⋅(nβ−l1β)+l1β⋅l1γ⋅(nα−l1α)), where nα and nβ are the number of cycles of α and β, respectively, and l1δ is the number of fixed points of δ, for all δ∈{α,β,γ}. Moreover, we study the dimension of these two polytopes for Latin squares of order up to 9.
01001101 01100001 01101110 01101001 01100110 01100101 01110011 01110100 01100001 01100011 01101001 01101111 01101110 01100101 01110011 00100000 01100100 01100101 00100000 01101001 01100100 01100101 01101110 01110100 01101001 01100100 01100001 01100100: Manifestaciones de identidad
(2023) Plata de Avila, Antonio; Rosado-Garcés, Miguel-Pablo; Universidad de Sevilla. Departamento de Escultura e Historia de las Artes Plásticas
El juego a través de la imagen digital se ha ido masificando como producto creciente en la vida cotidiana de millones de niños, jóvenes y adultos, de forma que ha generado una conmoción revolucionaria para toda una generación, convirtiéndose en una influencia creciente del siglo XXI. Con la referencia al arte de las telecomunicaciones generamos un proyecto pictórico y escultórico cuya base reside en la experiencia identitaria a través del personaje o avatar, de modo que genere en el espectador una experiencia inmersiva en el juego, llegando a generar impulsos de empatía y sensación de identificación con la obra. El proyecto “01001101 01100001 01101110 01101001 01100110 01100101 01110011 01110100 01100001 01100011 01101001 01101111 01101110 01100101 01110011 00100000 01100100 01100101 00100000 01101001 01100100 01100101 01101110 01110100 01101001 01100100 01100001 01100100” plantea por medio del código binario, la incógnida del titulo de cada obra pictórica, haciendo analogía al ámbito de la binarizacion del géreno (hombre-mujer) y sus consecuencias en las manifestaciones identitarias del individuo o su condicionamiento para ser incluido en el paradigma binario.
05-KIN
(Diputación Provincial ; Colegio Oficial de Arquitectos de León, Delegación de Zamora, 2000) Barreno Gutiérrez, Julio; Universidad de Sevilla. Departamento de Proyectos Arquitectónicos
Proyecto que obtuvo un accesit en el Concurso de ideas para la edificación de oficinas en la Plaza Viriato de Zamora.
1 V CMOS subthreshold log domain PDM
(Springer, 2003) Serra Graells, Francesc; Huertas Díaz, José Luis; Comisión Interministerial de Ciencia y Tecnología (CICYT). España; European Union (UE)
A new CMOS circuit strategy for very low-voltage Pulse-Duration Modulators (PDM) is proposed. Optimization of voltage supply scaling below the sum of threshold voltages is based on Instantaneous Log Companding processing through the MOSFET operating in weak inversion. A 1 V VLSI PDM circuit for very low-voltage audio applications such as Hearing Aids is presented, showing good agreement between simulated and experimental data.
El 1% cultural y su repercusión en el patrimonio histórico artístico a través de las construcciones escolares
(1987-06-19) García Fernández, María Pilar; Sánchez Arcenegui, Manuel; Universidad de Sevilla. Departamento de Dibujo
1, 2, 3... ω: matemática, historia y epistemología
(Universidad Autónoma de Barcelona, 1997) Ferreirós Domínguez, José Manuel; Universidad de Sevilla. Departamento de Filosofía y Lógica y Filosofía de la Ciencia; Estany, Anna; Quesada, Daniel
1,1,3,3-tetramethylguanidinium dihydrogenorthophosphate
(International Union of Crystallography, 2000) Criado Vega, Alberto; Diánez Millán, María Jesús; Pérez Garrido, Simeón; Fernandes, I. M L; Belsley, Michael Scott; Matos Gomes, Etelvina M. de; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Comisión Interministerial de Ciencia y Tecnología (CICYT). España
In the title compound, C 5 H 14 N 3 + H 2 PO 4 ˇ , the cation has a central guanidinium fragment with a planar geometry, as expected for a central C sp 2 atom with a small charge delocalization along the three C–N bonds. The crystal packing is governed by hydrogen bonds so that the phosphate anions are linked head to tail, forming chains running parallel to the c direction. These chains in turn are interconnected by hydrogen bonds to intermediate tetramethylguanidinium cations forming hydrogen-bonded molecular layers stacked parallel to the bc crystal planes
1,2,3-Triazoles from carbonyl azides and alkynes: filling the gap
(Royal Society of Chemistry, 2014) Haldón, Estela; Álvarez González, Eleuterio; Nicasio Jaramillo, María del Carmen; Pérez, Pedro J.; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Economía y Competitividad (MINECO). España; Junta de Andalucía
Electron deficient azides are challenging substrates in CuAAC reactions. Particularly, when N-carbonyl azides are applied the formation of N-carbonyl triazoles has not yet been observed. We report herein the first example of this class of reaction, with a copper-based system that efficiently enables the synthesis of N-carbamoyl 1,2,3-triazoles by [3+2] cycloaddition of N-carbamoyl azides and alkynes
1,4-Dideoxy-1,4-imino-d-arabinitol (DAB) Analogues Possessing a Hydrazide Imide Moiety as Potent and Selective α-Mannosidase Inhibitors
(American Chemical Society, 2020) Haarr, Marianne B.; López López, Óscar; Pejov, Ljupcho; Fernández-Bolaños Guzmán, José María; Lindbäck, Emil; Sydnes, Magne O.; Universidad de Sevilla. Departamento de Química orgánica
The synthesis of two polyhydroxylated pyrrolidines as 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) analogues bearing a hydrazide moiety is described. The DAB analogues act as selective and potent inhibitors of α-mannosidase in the submicromolar concentration ranges (Ki values ranging from 0.23 to 1.4 μM).
1–42 b -Amyloid peptide requires PDK1/nPKC/Rac 1 pathway to induce neuronal death
(Nature Publishing Group, 2013) Manterola, L.; Hernando Rodríguez, M.; Ruiz, A.; Jiménez Muñoz, Sebastián; Universidad de Sevilla. Departamento de Bioquímica y Biología Molecular
1–42 b -Amyloid peptide requires PDK1/nPKC/Rac 1 pathway to induce neuronal death L Manterola 1,12 , M Hernando-Rodr ı ́ guez 2,12 , A Ruiz 3,4 , A Apraiz 5 , O Arrizabalaga 5 , L Vello ́ n 6 , E Alberdi 3,4 , F Cavaliere 3,4 , HM Lacerda 7 , S Jimenez 8,9 , LA Parada 10 , C Matute 3,4 and JL Zugaza 4,5,11 1–42 b -Amyloid (A b 1–42 ) peptide is a key molecule involved in the development of Alzheimer’s disease. Some of its effects are manifested at the neuronal morphological level. These morphological changes involve loss of neurites due to cytoskeleton alterations. However, the mechanism of A b 1–42 peptide activation of the neurodegenerative program is still poorly understood. Here, A b 1–42 peptide-induced transduction of cellular death signals through the phosphatidylinositol 3-kinase (PI3K)/ phosphoinositol-dependent kinase (PDK)/novel protein kinase C (nPKC)/Rac 1 axis is described. Furthermore, pharmacological inhibition of PDK1 and nPKC activities blocks Rac 1 activation and neuronal cell death. Our results provide insights into an unsuspected connection between PDK1, nPKCs and Rac 1 in the same signal-transduction pathway and points out nPKCs and Rac 1 as potential therapeutic targets to block the toxic effects of A b 1–42 peptide in neurons.
1-Alquil-2-benciltio-4-imidazolcarbozaldehidos
(1967-10-31) Heredia Moreno, Antonia; Fernández Bolaños, José; Universidad de Sevilla. Departamento de Química orgánica
1.2V, 1.96mW @ 2.4GHz CMOS-90nm switched-transconductor mixer
(2010) Villegas Calvo, José Alberto; Vázquez García de la Vega, Diego; Rueda Rueda, Adoración; Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo; Gobierno de España; Junta de Andalucía
This paper presents the design of a fully differential double balanced switched transconductor mixer for ZigBee applications in the 2.4GHz band. It provides programmable conversion gain by using an active load stage. The design includes RF and LO input matching networks. It has been implemented in a 90nm 1P9M CMOS process. Post-layout simulations show conversion gains of 12dB/20dB, NF of 18.9dB/18.1dB and power consumption of 4.1mW/4.4mW at high and low gain mode respectively from a 1.2V power supply. It also offers very good linearity performance.
1.5V Rail-to-rail programmable-gain CMOS amplifier
(IEEE (Institute of Electrical and Electronics Engineers), 2004) Ramírez Angulo, Jaime; López Martín, Antonio J.; González Carvajal, Ramón; Lackey, C.; Universidad de Sevilla. Departamento de Ingeniería Electrónica
A 1.5V programmable-gain differential amplifier is implemented using a novel design technique for operating closed-loop amplifier circuits at very low supply voltages. It is based on the use of quasi-floating gate transistors, avoiding issues encountered in true floating-gate structures such as the initial floating-gate charge, offset drift with temperature, and gain-bandwidth product degradation. A prototype fabricated in a 0.5-/spl mu/m CMOS technology shows a 0.6% THD for almost rail-to-rail outputs and a 4 MHz unity-gain bandwidth.
1/f/sup y/ noise generation through a chaotic nonlinear switched-capacitor circuit
(Institute of Electrical and Electronics Engineers, 1992) Delgado Restituto, Manuel; Rodríguez Vázquez, Ángel Benito; Huertas Díaz, José Luis; Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo
A programmable switched-capacitor circuit for the generation of 1/f/sup y/ noise is reported. The circuit is described by a chaotic first-order piecewise-linear finite-difference equation which yields a hopping transition between regions of chaotic motions and hence produces 1/f/sup y/ noise. Experimental results illustrating the circuit performance are included.
10 + 2 viviendas colectivas en calle Torneo, Sevilla
(2016-09) Romero Cordobés, Francisco Javier
“10 años + haciendo Òmnia” : ciudad, instituciones y Web 2.0
(Universidad de Sevilla, 2010) Gasulla Ramon, Franscesk
Òmnia es un proyecto de la Generalitat de Catalunya que desde el año 1999 trabaja por hacer llegar las TIC a la ciudadanía para su empoderamiento digital. Una red de puntos distribuida por más de 80 pueblos y ciudades situados en zonas rurales, barrios socialmente desfavorecidos que se ha dotado de la filosofía 2.0 para visualizar su valor social, humanizar la manera de hacer y compartir la experiencia para favorecer su proyección. Diferentes estrategias multimedia relacionadas con la web 2.0 han cambiado la visión y relación que administración y ciudadanía mantienen para capitalizar el conocimiento generado.