905 research outputs found
Electro-optical Simulation of a-Si Thin-Film-Transistor Liquid Crystal Display Pixels
An analysis of an amorphous silicon (a-Si) thin-film-transistor liquid-crystal display (TFT-LCD) pixel is presented. The electro-optical model combines the electrical properties of the switching element and the optical performance of a twisted nematic (TN) liquid-crystal cell.Publicad
Multi-bit cascade ΣΔ modulator for high-speed A/D conversion with reduced sensitivity to DAC errors
El pdf del artículo es la versión post-print.This paper presents a ΣΔ modulator (ΣΔM) which combines single-bit and multi-bit quantization in a cascade architecture to obtain high resolution with low oversampling ratio. It is less sensitive to the non-linearity of the DAC than those previously reported, thus enabling the use of very simple analog circuitry with neither calibration nor trimming required.This work has been supported by Spanish C.I.C.Y.T. under contract TIC97-0580.Peer reviewe
A 2.5MHz 55dB Switched-Current BandPass ΣΔ Modulator for AM Signal Conversion.
We present a Switched-Current (SI) fourth-order bandpass ΣΔ modulator IC prototype. It uses fully-differential circuits in 0.8μm CMOS technology to obtain a Dynamic Range (DR) larger than 55dB at 2.5MHz center frequency with 30kHz bandwidth - in accordance to the requirements of AM digital receivers. The prototype incorporates a single-ended to fully-differential current-mode buffer for testing purposes. The power consumption of the whole prototype (modulator plus buffer) is 60mW from a 5V supply voltage.This work has been supported by the European Union, under ESPRIT Project 8795-AMFIS.Peer reviewe
A CMOS fully-differential bandpass ΣΔ modulator using switched-current circuits
Comunicación presentada al "38 th MWSCAS" celebrado en Rio de janeiro del 13 al 16 de Agosto de 1995.This paper presents a fourth-order bandpass
sigma-delta modulator that has been designed using fully-differential switched-current circuits in a 0.8μm CMOS technology. The modulator prototype has been obtained by applying a lowpass to bandpass transformation
to a second-order lowpass ΣΔ modulator.
Specifications are SNR [email protected]±15Khz, for a clock frequency of 1OMhz. Preliminary results from the fabricated prototype obtains the correct noise shaping up to 2.5Mhz clock frequency.Peer reviewe
Tools for Automated Design of ΣΔ Modulators
We present a set of CAD tools to design ΣΔ modulators. They use statistical optimization to calculate optimum specifications for the building blocks used in the modulators, and optimum sizes for the components in these blocks. Optimization procedures at the modulator level are equation-based, while procedures at the cell level are simulation-based. The toolset incorporates also an advanced ΣΔ behavioral simulator for monitoring and design space exploration. We include measurements taken from two silicon prototypes: 1) a 17bit@40kHz output rate fourth-order low-pass modulator; and 2) a [email protected] central freq@10kHz bandwidth band-pass modulator. The first uses SC fully-differential circuits in a 1.2μm CMOS double-metal double-poly technology. The second uses SI fully-differential circuits in a 0.8μm CMOS double-metal single-poly technology.This work has been supported by the CEE ESPRIT Program in the framework of the Project #8795 (AMFIS).Peer reviewe
Valorization alternatives for a highly unused biomass (Small-spotted catshark discards and by-products) in the framework of LIFE iSEAS project
1 póster presentado en el Total Food Conference 2014 Science and technology for the economic and sustainable exploitation of agri-food chain wastes and co-products, Norwich, Uk, 11-13 November (2014)The authors thank the finnancial support received from the LIFE + Program of the European Union (LIFE Project‐ LIFE13 ENV/ES/000131N
Electro-optic system for online light transmission control of polymer-dispersed liquid crystal windows
Polymer-dispersed liquid crystals (PDLCs) are formed by micro droplets of liquid crystal embedded in a flexible matrix and sandwiched between transparent electrodes. Large area units (several square meters) can be easily prepared. Opaque, transparent, and intermediate light transmission states can be achieved by applying appropriate electric fields These features allow their use in active windows for illumination, greenhouse regulation, and privacy, both on buildings and vehicles. An electro-optic system based on a micro controlled driver was implemented for on-line control of PDLC windows. The system may self regulate daylight or may be used as remote control.Publicad
El estreñimiento infantil, una visión desde la farmacia comunitaria
El estreñimiento en los niños es una de las consultas frecuentes en la farmacia comunitaria. Las precauciones básicas en la alimentación del lactante y el conocimiento de las pautas apropiadas en la introducción de nuevos alimentos se relacionan con la maduración progresiva de los sistemas digestivo y metabólico. El estreñimiento infantil se acompaña de una serie de síntomas cuya trascendencia es necesario reconocer y valorar con el fin de recomendar la consulta al médico o realizar la indicación farmacéutica correspondiente. Las papillas existentes en el mercado español pueden resultar útiles para mejorar el estreñimiento infantil, ya que aportan más fibra, disminuyendo la consistencia de las heces y también ejerciendo un efecto prebiótico (añadiendo FOS e inulina). Otras aportan fibra alimentaria, añadiendo mayor cantidad de pulpas de fruta. La educación dirigida a las madres en cuanto a hábitos alimentarios y una adecuada elección de los productos dietéticos indicados en esta situación permiten, en muchas ocasiones, resolver el problema sin necesidad de recurrir a tratamientos farmacológicos, no siempre conveniente
Optimisation of the extraction and purification of chondroitin sulphate from head by-products of Prionace glauca by environmental friendly processes
8 páginas, 3 figuras, 3 tablasThe goal of the present work was to optimise the different environmental friendly processes involved in the extraction and purification of chondroitin sulphate (CS) from Prionace glauca head wastes. The experimental development was based on second order rotatable designs and evaluated by response surface methodology combined with a previous kinetic approach. The sequential stages optimised were: (1) the enzymatic hydrolysis of head cartilage catalysed by alcalase (55.7 °C/pH 8.2); (2) the chemical treatment of enzyme hydrolysates by means of alkaline-hydroalcoholic saline solutions (NaOH: 0.54 M, EtOH: 1.17 v, NaCl: 2.5%) to end the protein hydrolysis and to precipitate and selectively redissolve CS versus the peptidic material and (3) the selective purification and concentration of CS and the concomitant protein permeation of extracts which were obtained from previous treatment using ultrafiltration and diafiltration (UF–DF) technologies at two different cut-offsFinancial support from projects MARMED 2011-1/164 (Atlantic Area Programme, EU), 0687_NOVOMAR_1_P (POCTEP Programme, EU) and iSEAS LIFE13 ENV/ES/000131 (LIFE+ Programme, EU) is acknowledgedPeer reviewe
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