نتایج جستجو برای: spectral doppler
تعداد نتایج: 208190 فیلتر نتایج به سال:
Different types and sizes of micro- and nanoparticles have been synthesized and developed for numerous applications. It is crucial to characterize the particle sizes. Traditional dynamic light scattering, a predominant method used to characterize particle size, is unable to provide depth resolved information or imaging functions. Doppler variance optical coherence tomography (OCT) measures the ...
The spectral Doppler mitral flow pattern, alone or combined with tissue Doppler mitral annulus velocity, can be used to predict left ventricular (LV) filling pressure in humans, whereas invasive hemodynamic measurements are still required in the rat. This study was undertaken to assess whether LV end-diastolic pressure (LVEDP) can be estimated using Doppler echocardiography in the rat after myo...
background: determining the clinical significance of cardiac murmurs is widely considered in equine practice. pulmonary murmurs are commonly detected in athletic horses. echocardiography plays a leading role in assessment of these murmurs. objectives: echocardiographic evaluation of horses with pulmonary regurgitation and determining the importance of pulmonary valve murmurs. methods: a total n...
The real issues of communicating over radio channels with continuous time chaotic signals are addressed. Synchronized and nonsynchronized methods are assessed. The modeling of radio channels (including multipath and Doppler) is reviewed, and then the effect on chaotic signals is investigated. The bandwidth efficiency of chaotic communication systems is discussed, and compared to conventional me...
Acquiring the raindrop size distribution (DSD) from radar data is still a challenge. For profiling radar, this distribution can be estimated from the Doppler spectra. However the Doppler spectrum is not a direct measure of the DSD. The radial component of the wind shifts the Doppler spectrum related to the raindrop size distribution along the Doppler velocity interval. Furthermore, the Doppler ...
We present model calculations to the observed spectral variability in the γ-ray spectrumof the ultraluminous blazartype quasar PKS 0528+134.We argue that the observed appearance of a spectral break between theCOMPTELand theEGRET energy range can plausibly be explained by a variation of the Doppler beaming factor in the framework of a relativistic jet model for AGNs, combining the ERC and the SS...
Thus P' represents the maximum value of the spectral absorption coefficient if only Doppler broadening occurred; b, bc, and bD denote, respectively, the natural half-width,t the half-width resulting from collision (Lorentz) broadening, and the half-width produced by Doppler broadening; S is the integrated intensity of the spectral line under study whose center lies at wo; m is the mass of the r...
For the estimation of the autocorrelation and the auto-spectral density from irregularly sampled laser Doppler data sets three types of estimators are known, the slotting technique, the direct spectral estimation and the interpolation with filter correction. In this paper similar estimation techniques are discussed for the cross-correlation and the cross-spectral density case of two randomly sa...
We present model calculations to the observed spectral variability in the γ-ray spectrum of the ultraluminous blazar-type quasar PKS 0528+134. We argue that the observed appearance of a spectral break between the COMPTEL and the EGRET energy range can plausibly be explained by a variation of the Doppler beaming factor in the framework of a relativistic jet model for AGNs, combining the ERC and ...
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