نتایج جستجو برای: photon attenuation coefficient
تعداد نتایج: 284445 فیلتر نتایج به سال:
Can current experimental techniques and analytical procedures produce x-ray absorption fine structure (XAFS) which is independent of the beam line or synchrotron used? We investigate the consequence upon XAFS interpretation of typical systematic errors, including determination of the edge energy, detector response and synchrotron bandwidth. Using the highest accuracy data set of the mass-attenu...
To solve noises affecting the performance of laser communication system problems, this paper studies mathematical model in atmospheric attenuation condition, sets up atmospheric attenuation coefficient of the primary factor aerosol (haze) according to the absorbing and scattering characteristics of the atmosphere, gives output SNR(Signal to Noise Ratio) models under atmosphere attenuation based...
The excess ultrasonic attenuation caused by adding glycogen and inorganic phosphate to liver homogenates has been studied to determine the underlying differences between attenuation coefficients of normal and diffusely diseased livers. Results show that glycogen has a higher than average specific absorption coefficient compared to other large molecular weight biomolecules. Since the glycogen co...
Ultrasonic backscattering measurements by means of spatial averaging technique were carried out in steel to determine the ultrasonic attenuation coefficient. The attenuation coefficients were evaluated from the exponential decay of the backscattering signal. The results were compared with those obtained by evaluating the amplitude decay of the main pulse. Good agreement is observed provided the...
Quantitative information on photon scattering around brachytherapy sources is needed to develop dose calculation formalisms capable of predicting dosimetric parameters with minimal empiricism. Photon absorption and scatter around brachytherapy sources can be characterized using the tissue attenuation factor, defined as the ratio of dose in water to water kerma in free space. In this study, the ...
Depth-resolved information is essential for ocean research. For this study, we developed a shipborne photon-counting lidar depth-resolved oceanic plankton observation. A pulsed fiber laser with frequency doubling to 532 nm acts as light source, generating single pulse at the micro-joule level width of less than 1 ns. The receiver capable simultaneously detecting elastic signal two orthogonal po...
UNLABELLED CT images represent essentially noiseless maps of photon attenuation at a range of 40-140 keV. Current dual-modality PET/CT scanners transform them into attenuation coefficients at 511 keV and use these for PET attenuation correction. The proportional scaling algorithms hereby used account for the different properties of soft tissue and bone but are not prepared to handle material wi...
[Abstract] We report an outstanding phenomenon related to the X-ray attenuation induced by carbon nanotubes (CNTs). We observed that the mass attenuation coefficient of CNTs was significantly higher (> 100%) than that observed for highly oriented pyrolytic graphite (HOPG) and fullerenes (C60). The attenuation coefficient of CNTs increased by reducing the sample thickness. This attenuation pheno...
Introduction: Osteoporosis is a bone disease in which there is a reduction in the amount of bone mineral content leading to an increase in the risk of bone fractures. The affected individuals not only have to go through lots of pain and suffering but this disease also results in high economic costs to the society due to a large number of fractures. A timely and accurate diagnosis of this disea...
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