scholarly journals Quantitative Global-Local Mixing for Accessible Skew Products

2021 ◽  
Author(s):  
Paolo Giulietti ◽  
Andy Hammerlindl ◽  
Davide Ravotti
Keyword(s):  
Spectral Measure ◽  
Low Frequency ◽  
Almost Periodic ◽  
Careful Choice ◽  
Rapid Mixing ◽  
Infinite Measure ◽  
Skew Products ◽  
Transfer Operators ◽  
Frequency Behavior ◽  
Dense Set

AbstractWe study global-local mixing for a family of accessible skew products with an exponentially mixing base and non-compact fibers, preserving an infinite measure. For a dense set of almost periodic global observables, we prove rapid mixing, and for a dense set of global observables vanishing at infinity, we prove polynomial mixing. More generally, we relate the speed of mixing to the “low frequency behavior” of the spectral measure associated to our global observables. Our strategy relies on a careful choice of the spaces of observables and on the study of a family of twisted transfer operators.

Magnetic Permeability and Relaxation Frequency in High Frequency Magnetic Materials.

2001 ◽  
Vol 674 ◽  
Author(s):  
M.I. Rosales ◽  
H. Montiel ◽  
R. Valenzuela
Keyword(s):  
High Frequency ◽  
Domain Walls ◽  
Magnetocrystalline Anisotropy ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Anisotropy Constant ◽  
Relaxation Frequency ◽  
Resonance Relaxation ◽  
Frequency Behavior

ABSTRACTAn investigation of the frequency behavior of polycrystalline ferrites is presented. It is shown that the low frequency dispersion (f < 10 MHz) of permeability is associated with the bulging of pinned domain walls, and has a mixed resonance-relaxation character, closer to the latter. It is also shown that there is a linear relationship between the magnetocrystalline anisotropy constant, K1, and the relaxation frequency. The slope of this correlation depends on the grain size. Such a relationship could allow the determination of this basic parameter from polycrystalline samples.

Erratum: Low‐frequency behavior of coupled Josephson junctions near phase locking [Appl. Phys. Lett. 41, 566 (1982)]

1983 ◽  
Vol 42 (3) ◽  
pp. 305-305 ◽  
Author(s):  
A. K. Jain ◽  
K. K. Likharev ◽  
J. E. Lukens ◽  
J. E. Sauvageau
Keyword(s):  
Josephson Junctions ◽  
Phase Locking ◽  
Low Frequency ◽  
Frequency Behavior

Inertia, Damping, and Wave Excitation of Heaving Coaxial Cylinders

2012 ◽  
Author(s):  
Fun Pang Chau ◽  
Ronald W. Yeung
Keyword(s):  
Low Frequency ◽  
Bottom Surface ◽  
Hydrodynamic Coefficients ◽  
Wave Excitation ◽  
Hydrodynamic Properties ◽  
Coaxial Cylinders ◽  
Ocean Wave Energy ◽  
Matched Eigenfunction Expansions ◽  
Frequency Behavior ◽  
Analytical Expressions

The method of matched eigenfunction expansions is applied in this paper to obtain the hydrodynamic coefficients of a pair of coaxial cylinders, each of which can have independent movement. The geometry idealizes a device for extracting ocean wave energy in the heave mode. The effects of geometric variations and the interaction between cylinders on the hydrodynamic properties are discussed. Analytical expressions for the low-frequency behavior of the hydrodynamic coefficients are also derived. The wave-exciting force on the bottom surface of either one of the cylinders is derived using the radiation solutions, with a generalized form of the Haskind relation developed for this geometry. The presented results are immediately applicable to examine free motion of coaxial cylinders in a wave field.

The Cremer impedance: An investigation of the low frequency behavior

2019 ◽  
Vol 459 ◽  
pp. 114844 ◽  
Author(s):  
Zhe Zhang ◽  
Hans Bodén ◽  
Mats Åbom
Keyword(s):  
Low Frequency ◽  
Frequency Behavior

Low-frequency viscoelastic properties of canine femoral artery in vivo

1979 ◽  
Vol 236 (5) ◽  
pp. H720-H724
Author(s):  
P. Sipkema
Keyword(s):  
Young’S Modulus ◽  
Femoral Artery ◽  
Constant Pressure ◽  
Young's Modulus ◽  
Low Frequency ◽  
Absolute Value ◽  
Average Value ◽  
Mean Pressure ◽  
Frequency Behavior

Mechanical properties of the canine femoral artery in vivo are measured as a function of frequency (0.0025--0.1 Hz) and as a function of mean pressure (10--16 kPa). Sinusoidal pressure variations are generated with a servo-controlled occluder system. The absolute value of the Young's modulus increases with mean pressure (E = 0.63 X 10(5) exp(0.211P)-N.m-2) at 0.05 Hz; where P is pressure. At heart rate frequencies (average value 2.22 Hz) this relation is: E = 1.25 X 10(5) exp(0.175P) N.m-2. The phase angle of the Young's modulus is independent of pressure at both frequencies. At 0.05 Hz we found: phi = 0.189 - 0.00788 P radians and at 2.22 Hz: phi = 0.0723 + 0.000428 P. The slope of both lines is not significantly different from zero slope (alpha = 0.05). Frequency dependence is studied at a constant pressure level (Pr, average value 14.3 kPa) just below the animals' mean pressure levels (average value 15.9 kPa). The frequency behavior of the elastic modulus is fitted with a function with two poles and two zeros (poles at 0.003 and 0.038 Hz; zeros at 0.0022 and 0.03 Hz).

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