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Gurumurthy Komanapalli Rajeshwari Pandey Neeta Pandey 《International Journal of Circuit Theory and Applications》2019,47(5):666-685
The objective of this brief is to introduce four new structures of electronically tunable sinusoidal oscillators (SOs) designed using operational transresistance amplifier (OTRA). Each of the proposed SO consists of forward path derived from a generic structure along with one/two OTRA-based resistive gain stages or differentiator in its feedback path. All the proposed SOs enjoy independent tuning of the frequency of oscillation (FO) through resistors without affecting the condition of oscillation (CO). Further, all topologies are found to exhibit low fo sensitivities at all frequencies with respect to circuit parameters, and the second topology is capable of achieving very low frequencies (VLFs) using less RC component spread and provides linear tuning too. The fourth circuit provides quadrature output. The proposed SOs have been successfully implemented and verified in 180-nm CMOS technology node using ADE (analog design environment) tool Cadence Virtuoso. Both prelayout and postlayout simulation results have been included. To assess the oscillator prefabrication performances, Monte Carlo and process-voltage-temperature (PVT) analyses have been performed. The total harmonic distortion (THD) is observed to be less than 3.5%. 相似文献
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A titania nanotube-array room-temperature sensor for selective detection of hydrogen at low concentrations 总被引:4,自引:0,他引:4
Varghese OK Mor GK Grimes CA Paulose M Mukherjee N 《Journal of nanoscience and nanotechnology》2004,4(7):733-737
A tremendous variation in electrical resistance, from the semiconductor to metallic range, has been observed in titania nanotube arrays at room temperature, approximately 25 degrees C, in the presence of < or = 1000 ppm hydrogen gas. The nanotube arrays are fabricated by anodizing titanium foil in an aqueous electrolyte solution containing hydrofluoric acid and acetic acid. Subsequently, the arrays are coated with a 10 nm layer of palladium by evaporation. Electrical contacts are made by sputtering a 2 mm diameter platinum disk atop the Pd-coated nanotube array. These sensors exhibit a resistance variation of the order of 10(4) in the presence of 100 ppm hydrogen at 25 degrees C. The sensors demonstrate complete reversibility, repeatability, high selectivity, negligible drift and wide dynamic range. The nanoscale geometry of the nanotubes, in particular the points of tube-to-tube contact, is believed to be responsible for the outstanding hydrogen gas sensitivities. 相似文献
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Solution polymerization of methylmethacrylate (MMA) initiated by p-acetylbenzylidene triphenylarsonium ylide in dioxane was carried out at 60±0.2 °C up to 10 hrs. in a polymerization tube
under a nitrogen atmosphere. The values of the initiator and the monomer exponent were computed as 0.46 and 1.03, respectively.
The overall activation energy and kp2/kt were calculated as 53 KJ/mole and 1.19 × 10−2 L/mol·s, respectively for the polymerization. 相似文献
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Pottayil Uma Devi Muralidharan Kannai V. Paulose Jacob Koshy Alathoor D. Damodaran 《Journal of the American Ceramic Society》1991,74(10):2679-2682
The percolation behavior of normal-state thermopower, resistivity, and superconductivity have been studied in YBa2 Cu3 O7-δ ─Ag (YBCO─Ag) composite systems. The normal-state resistivity and thermopower show a percolation threshold at a Ag volume fraction ( V Ag ) of 20% to 30%, whereas the superconducting network shows a threshold at a V Ag of ≅70% to 80%. The results obtained from this study show that the YBCO─Ag composite obtained from Ag2 O and YBCO powders is uniformly distributed with Ag and YBCO remaining as separate phases without changing their characteristics. The measurements of thermopower indicate that the normal-state thermopower and phonon-drag thermopower are affected by the Ag addition. The stability of YBCO is increased when it is in composite form. 相似文献
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Multimedia Tools and Applications - By embracing Generative Adversarial Networks (GAN), several face-related applications have significantly benefited and achieved unparalleled success. Inspired by... 相似文献
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