The efficiency of practical methods for phase retrieval from the intensity distribution in Fresnel (nearfield) images is investigated in the paraxial limit. The aim was to develop a robust and efficient algorithm for phase retrieval from aperiodic objects in the limit where phases may vary continuously by several multiples of 2ð across the sampled field. The equations for Fresnel propagation of...

Expressive timing is vital for the aesthetic quality that makes us appreciate performed music. It is a largely tacit skill that musicians acquire by practice. A long-standing intuition is that expressive timing is closely related to the concept of motion. This view leads naturally to the adoption of a dynamical systems approach to the study of expressive timing. A well-known visualization techn...

In this note we present a novel stability analysis method for DC to DC series resonant converters which relies on the phase plane technique. This method gives more insight into the rationale behind the stability conditions because these are obtained from geometrical considerations instead of eigenvalues of linear discrete time approximations as presented in previous works. The proposed method a...

This article presents a new method for measuring longitudinal strain in a short-axis section of the heart using harmonic phase magnetic resonance imaging (HARP-MRI). The heart is tagged using 1-1 SPAMM at end-diastole with tag surfaces parallel to a short-axis imaging plane. Two or more images are acquired such that the images have different phase encodings in a direction orthogonal to the imag...

We present the computational results on the formation of diverse complex 3D vortex lattices by a designed superposition of multiple plane waves. Special combinations of multiples of three noncoplanar plane waves with a designed relative phase shift between one another are perturbed by a nonsingular beam to generate various complex 3D vortex lattice structures. The formation of complex gyrating ...

The propagation of plane waves in an isotropic chiral medium (ICM) is investigated. Simple conditions are derived — in terms of the constitutive parameters of the ICM— for the phase velocity to be directed opposite to the direction of power flow. It is demonstrated that phase velocity and power flow may be oppositely directed provided that the magnetoelectric coupling is sufficiently strong.

Background in music performance research For the past few decades there has been considerable scientific interest in expression in music performance (Gabrielsson, 2003). A particularly relevant aspect of music performance is expressive timing, that is, the fluctuations of tempo during a performance. Accordingly, expressive timing has been one of the major topics in music performance research. A...

The design of phase plates based on a phase-retrieval algorithm has been shown to be successful in achieving high order super-Gaussian distributions in the far field; however, these phase plates exhibit wide-angle scattering losses due to phase discontinuities. We report that, by starting with a distributed phase plate that is a strictly continuous surface and using only a few cycles of a phase...

Sliding frictional interfaces at a range of length scales are observed to generate travelling waves; these are considered relevant, for example, to both earthquake ground surface movements and the performance of mechanical brakes and dampers. We propose an explanation of the origins of these waves through the study of an idealized mechanical model: a thin elastic plate subject to uniform shear ...

BACKGROUND Ventricular function has conventionally been characterized using indexes of systolic (contractile) or diastolic (relaxation/stiffness) function. Systolic indexes include maximum elastance or equivalently the end-systolic pressure volume relation and left ventricular ejection fraction. Diastolic indexes include the time constant of isovolumic relaxation - and the end-diastolic pressur...