Space-borne Synthetic Aperture Radar (SAR) imaging is often considered to possess both day/night and all weather operational capabilities. Whereas the rst argument is true since we are dealing with an active sensor; the second does not hold in cases for which the operating frequencies are above 3 GHz. Indeed, the SAR performance can be signi cantly affected by atmospheric effects (losses), espe...

An efficient reconstruction method for myocardial perfusion single-photon emission computed tomography (SPECT) has been developed which compensates simultaneously for attenuation, scatter, and resolution variation. The scattered photons in the primary-energy-window measurements are approximately removed by subtracting the weighted scatter-energy-window samples. The resolution variation is corre...

Millimeter wave band is still under exploited compared to the microwave band and it can be a potential frequency band for resolving the spectrum congestion. Therefore, millimeter-wave networks are undergoing intensive development to meet the necessity for high speed wireless data transmission. However, millimeter-wave band is largely affected by attenuation due to rain. While calculating link b...

In this paper we show that the standard causality condition for attenuated waves, i.e. the Kramers-Kronig relation that relates the attenuation law and the phase speed of the wave, is necessary but not sufficient for causality of a wave. By causality of a wave we understand the property that its wave front speed is bounded. Although this condition is not new, the consequences for wave attenuati...

Background: In this study, a method for linear attenuation coefficient calculation was introduced.Methods: Linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. The calculation was done for Cerrobend as a common radiotherapy modifier and Mercury.Results: The values...

This study proposes the use of a linear and geometrically nonlinear inerter-based resonator in locally resonant acoustic metamaterials (LRAMs) evaluates performance on low-frequency wave attenuation. The LRAM is modeled as 1D chain system composed mass-in-mass unit cells connected by springs, geometrical nonlinearity achieved two lateral inerters linking lumped mass symmetrically with respect t...

background: in this study, a method for linear attenuation coefficient calculation was introduced. methods: linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. the calculation was done for cerrobend as a common radiotherapy modifier and mercury. results: the valu...