8,598 research outputs found
Biquadratic Filter Applications Using a Fully-Differential Active-Only Integrator
A new class of active filters, real active-only filters is described and possible implementation issues of these filters are discussed. To remedy these issues, a fully-differential active-only integrator block built around current controlled current conveyors is presented. The integration frequency of the proposed circuit is adjustable over a wide frequency range. As an application, a real active-only filter based on the classical two-integrator loop topology is presented and designed. The feasibility of this filter in a 0.35µm CMOS process is verified through SPECTRE simulation program in the CADENCE design tool
Invariance quantum group of the fermionic oscillator
The fermionic oscillator defined by the algebraic relations cc^*+c^*c=1 and
c^{2}=0 admits the homogeneous group O(2) as its invariance group. We show
that, the structure of the inhomogeneous invariance group of this oscillator is
a quantum group.Comment: 7 A4 page
Quantum Group Covariance and the Braided Structure of Deformed Oscillators
The connection between braided Hopf algebra structure and the quantum group
covariance of deformed oscillators is constructed explicitly. In this context
we provide deformations of the Hopf algebra of functions on SU(1,1). Quantum
subgroups and their representations are also discussed.Comment: 12 pages, to be published in JM
Modelling the components of binaries in Hyades: The dependence of the mixing-length parameter on stellar mass
We present our findings based on a detailed analysis for the binaries of the
Hyades, in which the masses of the components are well known. We fit the models
of components of a binary system to the observations so as to give the observed
total V and B-V of that system and the observed slope of the main-sequence in
the corresponding parts. According to our findings, there is a very definite
relationship between the mixing-length parameter and the stellar mass. The
fitting formula for this relationship can be given as , which is valid for stellar masses greater than
0.77 M_sun. While no strict information is gathered for the chemical
composition of the cluster, as a result of degeneracy in the colour-magnitude
diagram, by adopting Z=0.033 and using models for the components of 70 Tau and
theta^2 Tau we find the hydrogen abundance to be X=0.676 and the age to be 670
Myr. If we assume that Z=0.024, then X=0.718 and the age is 720 Myr. Our
findings concerning the mixing length parameter are valid for both sets of the
solution. For both components of the active binary system V818 Tau, the
differences between radii of the models with Z=0.024 and the observed radii are
only about 4 percent. More generally, the effective temperatures of the models
of low mass stars in the binary systems studied are in good agreement with
those determined by spectroscopic methods.Comment: 11 pages, 7 figures, accepted for publication in MNRA
Evanescent incompressible strips as origin of the observed Hall resistance overshoot
In this work we provide a systematic explanation to the unusual non-monotonic
behavior of the Hall resistance observed at two-dimensional electron systems.
We use a semi-analytical model based on the interaction theory of the integer
quantized Hall effect to investigate the existence of the anomalous, \emph{i.e}
overshoot, Hall resistance . The observation of the overshoot resistance
at low magnetic field edge of the plateaus is elucidated by means of
overlapping evanescent incompressible strips, formed due to strong magnetic
fields and interactions. Utilizing a self-consistent numerical scheme we also
show that, if the magnetic field is decreased the decreases to its
expected value. The effects of the sample width, temperature, disorder strength
and magnetic field on the overshoot peaks are investigated in detail. Based on
our findings, we predict a controllable procedure to manipulate the maxima of
the peaks, which can be tested experimentally. Our model does not depend on
specific and intrinsic properties of the material, provided that a single
particle gap exists.Comment: A theoretical follow-up paper of arXiv:1007.258
Numerical Analysis of 1/28 Scaled HTGR Reactor Building Test Facility Response to Depressurization Event
Depressurized Loss of Forced Cooling (DLOFC) accident is an important type of accident
scenario in High Temperature Gas-Cooled Reactor (HTGR) design which is initiated
by a break in Helium Pressure Boundary (HPB). This class of accident scenarios results
in a depressurization of primary helium coolant system with subsequent release of helium
into the Reactor Building (RB) and to the atmosphere through Vented Low Pressure
Containment (VLPC). After the total depressurization of helium depending on the specific
accident scenarios, it is also possible that air enters into the Reactor Pressure Vessel (RPV)
through the RB which can potentially react with fuel and the reactor internal components
such as nuclear-grade graphite.
In this study, GOTHIC model of a 1/28-scaled simplified test facility was developed
to analyze the depressurization scenarios and validate them against the experimental data.
Simulations were conducted in three phases by following the experiment sequence. In
the first phase, natural leakage from the RB was modeled with two different methods to
prepare the model for further analysis. In the second phase, post-depressurization refill
of air into the RB compartments was analyzed and results were validated against experimental
data. In third phase, two hypothetical depressurization scenarios were analyzed
and results were compared with experimental data. Simulation results were found to be
consistent with experimental data
Foraging swarms as Nash equilibria of dynamic games
Cataloged from PDF version of article.The question of whether foraging swarms can form as a result of a noncooperative game played by individuals is shown here to have an affirmative answer. A dynamic game played by N agents in 1-D motion is introduced and models, for instance, a foraging ant colony. Each agent controls its velocity to minimize its total work done in a finite time interval. The game is shown to have a unique Nash equilibrium under two different foraging location specifications, and both equilibria display many features of a foraging swarm behavior observed in biological swarms. Explicit expressions are derived for pairwise distances between individuals of the swarm, swarm size, and swarm center location during foraging. © 2013 IEEE
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