7,683 research outputs found
A short survey on nonlinear models of the classic Costas loop: rigorous derivation and limitations of the classic analysis
Rigorous nonlinear analysis of the physical model of Costas loop --- a
classic phase-locked loop (PLL) based circuit for carrier recovery, is a
challenging task. Thus for its analysis, simplified mathematical models and
numerical simulation are widely used. In this work a short survey on nonlinear
models of the BPSK Costas loop, used for pre-design and post-design analysis,
is presented. Their rigorous derivation and limitations of classic analysis are
discussed. It is shown that the use of simplified mathematical models, and the
application of non rigorous methods of analysis (e.g., simulation and
linearization) may lead to wrong conclusions concerning the performance of the
Costas loop physical model.Comment: Accepted to American Control Conference (ACC) 2015 (Chicago, USA
Examination of evidence for collinear cluster tri-partition
In a series of the experiments at different time-of-flight spectrometers of
heavy ions we have observed manifestations of a new at least ternary decay
channel of low excited heavy nuclei. Due to specific features of the effect, it
was called collinear cluster tri-partition (CCT). The experimental results
obtained initiated a number of theoretical articles dedicated to different
aspects of the CCT. We compare theoretical predictions with our experimental
data, only partially published so far. The model of one of the most populated
CCT modes that gives rise to the so called "Ni-bump" is discussed. Detection of
the 68-72Ni fission fragments with a kinetic energy E<25 MeV at the
mass-separator Lohengrin is proposed for an independent experimental
verification of the CCT.Comment: 16 pages, 14 figure
Effects of spin polarization on resonant photoemission from d-f states in TbNi2Mnx compounds
Resonant photoemission in narrow-band materials is described by the sum of first-and secondorder transitions, their quantum-mechanical interference leads to an increase in the spectrum from the valence bands and the appearance of an asymmetric dependence on the photon energy. These effects are studied theoretically and experimentally using the example of three-component intermetallic compounds TbNi2Mnx. The competition between the elastic and inelastic photoemission channels leads to a different dependence of photoemission spectra from nickel and manganese on photon energy. The elastic channel is realized on atoms with large magnetic moments, the inelastic Auger decay occurs on atoms with small moments. Β© 2018 The Authors, published by EDP Sciences.The research was carried out within the state assignment of FASO of Russia (theme uQ" ant" No. 01201463332), supported in part by RFBR (No. 18-02-00060) and UD RAS (No.15 -8 2-10). The authors express their gratitude to A. Preobrazhenskii and N. Vinogradov (synchrotron MAX-Lab, Lund, Sweden) for their assistance in carrying out experiments
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