182 research outputs found
Low frequency and Microwave Magnetoelectric Effects in Thick Film Heterostructures of Lithium Zinc Ferrite and Lead Zirconate Titanate
Magnetoelectric (ME) coupling at low frequencies and at x-band have been
investigated in layered samples containing zinc substituted lithium ferrite and
lead zirconate titanate (PZT). Multilayers of Li0.5-x/2ZnxFe2.5-x/2O4 (LZFO)
(x=0-0.4) and PZT were prepared by lamination and sintering of thick films. At
low frequencies (10-1000 Hz), the ME voltage coefficient for transverse fields
is higher than for longitudinal fields. With Zn substitution in the ferrite,
transverse coupling increases to a maximum for x=0.3 and then decreases for
higher x. Analysis based on our model for a bilayer implies an efficient
magneto-mechanical coupling with Zn substitution, resulting in strong ME
interactions. Microwave ME coupling is studied through measurements of shift in
the ferromagnetic resonance field due to an applied electric field. Estimated
ME constants from such data are in agreement with our model for a ferrite-PZT
bilayer.Comment: To be published in Solid State Communication
The morphological structure of images: the differential equations of morphological scale-space
<i>The Betrayal of Anne Frank</i>: A Refutation:Critical Analysis of the Argumentation and Use of Historical Sources
<i>The Betrayal of Anne Frank</i>: A Refutation:Critical Analysis of the Argumentation and Use of Historical Sources
Resonance magnetoelectric effects in layered magnetostrictive-piezoelectric composites
Magnetoelectric interactions in bilayers of magnetostrictive and
piezoelectric phases are mediated by mechanical deformation. Here we discuss
the theory and companion data for magnetoelectric (ME) coupling at
electromechanical resonance (EMR) in a ferrite-lead zirconate titanate (PZT)
bilayer. Estimated ME voltage coefficient versus frequency profiles for nickel,
cobalt, or lithium ferrite and PZT reveal a giant ME effect at EMR with the
highest coupling expected for cobalt ferrite-PZT. Measurements of resonance ME
coupling have been carried out on layered and bulk composites of nickel
ferrite-PZT. We observe a factor of 40-600 increase in ME voltage coefficient
at EMR compared to low frequency values. Theoretical ME voltage coefficients
versus frequency profiles are in excellent agreement with data. The resonance
ME effect is therefore a novel tool for enhancing the field conversion
efficiency in the composites
Compensated convexity methods for approximations and interpolations of sampled functions in Euclidean spaces: theoretical foundations
We introduce Lipschitz continuous and CÂą,Âą geometric approximation and interpolation methods for sampled bounded uniformly continuous functions over compact sets and over complements of bounded open sets in Rn by using compensated convex transforms. Error estimates are provided for the approximations of bounded uniformly continuous functions, of Lipschitz functions, and of C1,1 functions. We also prove that our approximation methods, which are differentiation and integration free and not sensitive to sample type, are stable with respect to the Hausdorff distance between samples
Video enhancement using adaptive spatio-temporal connective filter and piecewise mapping
This paper presents a novel video enhancement system based on an adaptive spatio-temporal connective (ASTC) noise filter and an adaptive piecewise mapping function (APMF). For ill-exposed videos or those with much noise, we first introduce a novel local image statistic to identify impulse noise pixels, and then incorporate it into the classical bilateral filter to form ASTC, aiming to reduce the mixture of the most two common types of noises - Gaussian and impulse noises in spatial and temporal directions. After noise removal, we enhance the video contrast with APMF based on the statistical information of frame segmentation results. The experiment results demonstrate that, for diverse low-quality videos corrupted by mixed noise, underexposure, overexposure, or any mixture of the above, the proposed system can automatically produce satisfactory results
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