1,721,833 research outputs found
Mathematical approach to large-signal modelling of electron devices
Full text linkA general purpose mathematical approach is proposed for the large-signal modelling of microwave electron devices (e.g. MESFETs, bipolar transistors, diodes, etc.). The mathematical model, which is based on mild assumptions valid both for field effect and bipolar devices in typical large-signal operating conditions, can easily be identified through conventional measurements and is particularly suitable for nonlinear microwave circuit analysis based on harmonic balance technique
Nonlinear Characterization of GaN Transistors under Dynamic Bias Operation
No full textThis paper describes a measurement technique suitable for the characterization of GaN-based FET devices, based on exciting the device simultaneously with low-frequency large-signal and high-frequency small-signal tones. This technique allows one to accurately characterize lowfrequency dispersion affecting this technology and at the same time the high-frequency behavior. We also discuss how to effectively use these measurements for modeling purpose
The fortified crusade-ayyubid settlements in the Petra valley: a study for a project of restoration
No full textTime-of-flight and activation experiments on 147Pm and 171Tm for astrophysics
No full textThe neutron capture cross section of several key unstable isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n,γ) measurement, for which high neutron fluxes and effective background rejection capabilities are required. As part of a new program to measure some of these important branching points, radioactive targets of 147Pm and 171Tm have been produced by irradiation of stable isotopes at the ILL high flux reactor. Neutron capture on 146Nd and 170Er at the reactor was followed by beta decay and the resulting matrix was purified via radiochemical separation at PSI. The radioactive targets have been used for time-of-flight measurements at the CERN n-TOF facility using the 19 and 185 m beam lines during 2014 and 2015. The capture cascades were detected using a set of four C6D6 scintillators, allowing to observe the associated neutron capture resonances. The results presented in this work are the first ever determination of the resonance capture cross section of 147Pm and 171Tm. Activation experiments on the same 147Pm and 171Tm targets with a high-intensity 30 keV quasi-Maxwellian flux of neutrons will be performed using the SARAF accelerator and the Liquid-Lithium Target (LiLiT) in order to extract the corresponding Maxwellian Average Cross Section (MACS). The status of these experiments and preliminary results will be presented and discussed as well. © The Authors, published by EDP Sciences, 2017
Effetti della monensina sulla forma a lievito miceliare di Candida albicans (Robin) Berkhout
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Power amplifier ACPR simulation using standard Harmonic balance tools
No full textThe adoption of complex digital modulation techniques in wireless communication systems has posed a great demand on RF and microwave power amplifier performance. When high linearity is required, the amplifier characterization is based on intermodulation or, more commonly, on Adjacent Channel Power Ratio (ACPR) and other parameters more directly related to the actual circuit operation. In this paper a previously proposed Harmonic Balance (HB) algorithm is adopted for the ACPR simulation of power amplifiers excited by digitally modulated signals. With respect to other approaches the proposed technique provides fast and accurate results using a conventional HB engine without requiring special purpose algorithms
Analisi lepidocronologica e fenologica della prateria a posidonia a nord della costa ionica calabrese
No full textStato dell'arte sui modelli teorici di danneggiamento per fatica nei materiali compositi
No full textRapporto di ricerca DIMNP - Università di Pis
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