Institution
Polytechnic University of Catalonia
Education•Barcelona, Spain•
About: Polytechnic University of Catalonia is a education organization based out in Barcelona, Spain. It is known for research contribution in the topics: Finite element method & Population. The organization has 16006 authors who have published 45325 publications receiving 949306 citations. The organization is also known as: UPC - BarcelonaTECH & Technical University of Catalonia.
Topics: Finite element method, Population, Context (language use), Computer science, Nonlinear system
Papers published on a yearly basis
Papers
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Pennsylvania State University1, Cornell University2, National Institute of Standards and Technology3, University of Maryland, College Park4, Academy of Sciences of the Czech Republic5, Polytechnic University of Catalonia6, Oak Ridge National Laboratory7, Institut für Kristallzüchtung8, University of Texas at Austin9, Temple University10
TL;DR: In this unique system an increase in the separation between the (SrO)2 planes, which can be achieved by changing n, bolsters the local ferroelectric instability and can be exploited to achieve a figure of merit at room temperature that rivals all known tunable microwave dielectrics.
Abstract: A new family of tunable microwave dielectrics with unparalleled performance at frequencies up to 125 GHz at room temperature has been created, using dimensionality to add and control a local ferroelectric instability in a system with exceptionally low dielectric loss. Tunable dielectric materials are valuable components for complex microwave circuitry, yet such materials tend to suffer losses when operated at microwave frequencies owing to intrinsic defects in their structures. Che-Hui Lee and colleagues have selected a family of dielectrics known to exhibit exceptionally low loss, and now show how these materials can be engineered to boost their tunability and attain levels of performance that rival all known tunable microwave dielectrics. The miniaturization and integration of frequency-agile microwave circuits—relevant to electronically tunable filters, antennas, resonators and phase shifters—with microelectronics offers tantalizing device possibilities, yet requires thin films whose dielectric constant at gigahertz frequencies can be tuned by applying a quasi-static electric field1. Appropriate systems such as BaxSr1−xTiO3 have a paraelectric–ferroelectric transition just below ambient temperature, providing high tunability1,2,3. Unfortunately, such films suffer significant losses arising from defects. Recognizing that progress is stymied by dielectric loss, we start with a system with exceptionally low loss—Srn+1TinO3n+1 phases4,5—in which (SrO)2 crystallographic shear6,7 planes provide an alternative to the formation of point defects for accommodating non-stoichiometry8,9. Here we report the experimental realization of a highly tunable ground state arising from the emergence of a local ferroelectric instability10 in biaxially strained Srn+1TinO3n+1 phases with n ≥ 3 at frequencies up to 125 GHz. In contrast to traditional methods of modifying ferroelectrics—doping1,2,3,11,12 or strain13,14,15,16—in this unique system an increase in the separation between the (SrO)2 planes, which can be achieved by changing n, bolsters the local ferroelectric instability. This new control parameter, n, can be exploited to achieve a figure of merit at room temperature that rivals all known tunable microwave dielectrics3.
207 citations
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TL;DR: In this article, the identity component of the Galois group of the variational equation (in the complex domain) is shown to be abelian, which is a necessary condition for meromorphic complete integrability.
Abstract: An inconvenience of all the known galoisian formulations of Ziglin's non-integrability theory is the Fhchsian condition at the singular points of the variational equations. We avoid this restriction. Moreover we prove that a necessary condition for meromorphic complete integrability (in Liouville sense) is that the identity component of the Galois group of the variational equation (in the complex domain) must be abelian. We test the efficacy of these new approaches on some examples. We will give some non academic applications in two following papers
207 citations
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TL;DR: New kinetics considering the relation between LCFA inhibitory substrate concentration and specific biomass content, as an approximation to the adsorption process, improved the model fitting and provided a better insight on the physical nature of the LCFA inhibition process.
207 citations
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TL;DR: In this paper, a suite of log-T fields with a normal distribution for point values but non-multinormal spatial correlation is presented, showing that scale dependence of T may, in part, be a consequence of high T zones being better connected than average or low T zones.
206 citations
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TL;DR: Bending-mode vibrations of carbon nanotube resonators were mechanically detected in air at atmospheric pressure by means of a novel scanning force microscopy method and the resonance frequency and the eigenmode shape of multiwall nanotubes are consistent with the elastic beam theory for a doubly clamped beam.
Abstract: Bending-mode vibrations of carbon nanotube resonators were mechanically detected in air at atmospheric pressure by means of a novel scanning force microscopy method The fundamental and higher order bending eigenmodes were imaged at up to 31 GHz with subnanometer resolution in vibration amplitude The resonance frequency and the eigenmode shape of multiwall nanotubes are consistent with the elastic beam theory for a doubly clamped beam For single-wall nanotubes, however, resonance frequencies are significantly shifted, which is attributed to fabrication generating, for example, slack The effect of slack is studied by pulling down the tube with the tip, which drastically reduces the resonance frequency
206 citations
Authors
Showing all 16211 results
Name | H-index | Papers | Citations |
---|---|---|---|
Frede Blaabjerg | 147 | 2161 | 112017 |
Carlos M. Duarte | 132 | 1173 | 86672 |
Ian F. Akyildiz | 117 | 612 | 99653 |
Josep M. Guerrero | 110 | 1197 | 60890 |
David S. Wishart | 108 | 523 | 76652 |
O. C. Zienkiewicz | 107 | 455 | 71204 |
Maciej Lewenstein | 104 | 931 | 47362 |
Jordi Rello | 103 | 694 | 35994 |
Anil Kumar | 99 | 2124 | 64825 |
Surendra P. Shah | 99 | 710 | 32832 |
Liang Wang | 98 | 1718 | 45600 |
Aharon Gedanken | 96 | 861 | 38974 |
María Vallet-Regí | 95 | 711 | 41641 |
Bonaventura Clotet | 94 | 784 | 39004 |
Roberto Elosua | 90 | 481 | 54019 |