«echo»
۳۶٬۰۰۵ نتیجهThe first coordinated observations of mid-latitude E-region quasi-periodic radar echoes and lower thermospheric 557.7-nm airglow
We present the first coordinated observations of quasi-periodic (QP) radar echoes from sporadic-E (Es) field-aligned irregularities (FAIs), OI 557.7-nm airglow, and neutral winds in a common volume over Shigaraki, Japan (34.9 N, 136.1 E) on the night of 5 August 2002 during the S
High-resolution skeletal muscle single-shot DW-EPI with optimized stimulated-echo preparation and SENSE
Introduction: High resolution skeletal muscle DTI is necessary in order to resolve muscles with small cross section and to delineate the fiber architecture in the boundaries between different muscles (aponeuroses) [1, 2]. High-resolution muscle single-shot (s-sh) DW-EPI is limite
Multiple gradient- and spin-echo EPI acquisition technique with z-shimming to compensate for susceptibility-induced off- resonance effects
INTRODUCTION – Images obtained with gradient-echo echo planar imaging (GRE-EPI) suffer from magnetic field variations within the brain, such as in regions adjacent to air-tissue interfaces. In these regions, magnetic field inhomogeneities cause spins to dephase more rapidly, resu
What a Plant Sounds Like: The Statistics of Vegetation Echoes as Received by Echolocating Bats
A critical step on the way to understanding a sensory system is the analysis of the input it receives. In this work we examine the statistics of natural complex echoes, focusing on vegetation echoes. Vegetation echoes constitute a major part of the sensory world of more than 800
Velocity reassignment echoes in proteins
A new echo phenomenon in proteins, a generalization of so-called temperature quench echoes, is introduced and shown to reveal, through molecular dynamics simulations, periodic motions ~normal modes! in proteins with phase coherence times of about one picosecond. The echoes are in
An Echo Canceller Based on the Structure of Dual-auxiliary Filters
The kernel of the echo canceller is the adaptive filter, which is used to estimate the impulse response of the echo path by means of an adaptive algorithm. During double-talk, the near-end input signal contains not only the echo of the far-end input signal, but also the near-end
Evaluations of an Echo Suppressor Based on a Frequency-domain Model of Highly Nonlinear Residual Echo
This paper presents evaluations of a nonlinear-echo suppressor based on a frequency-domain model of highly nonlinear residual echo. The residual-echo model, which is based on correlation between spectral amplitudes of residual echo and echo replica, is evaluated by a regression a
Lumbar degenerative disk disease: prospective comparison of conventional T2-weighted spin-echo imaging and T2-weighted rapid acquisition relaxation-enhanced imaging.
PURPOSE To compare conventional T2-weighted spin-echo imaging with a rapid acquisition relaxation enhanced (RARE) technique in the routine evaluation of lumbar degenerative disk disease. METHODS Thirty consecutive patients referred for evaluation of the lumbar spine for suspected
Dynamic Susceptibility Contrast Imaging using a multi-echo spiral sequence
Introduction To characterize microvasculature, one can perform a DCE-MRI experiment (a first injection of contrast agent (CA) to estimate the vessel wall permeability) followed by a DSC-MRI experiment (a second injection of CA to estimate relative blood volume (rCBV), relative bl
Acoustic Echo Cancellation from the Signal Using LMS Algorithm
The term Acoustic Echo Cancellation (AEC) refers to a process of removing echo from the received signal that contains one or more delayed signals (copies of the original signal). The primary step while cancelling an echo is to identify the transmitted signal which reappears with