نتایج جستجو برای: linear attenuation coefficient

تعداد نتایج: 671039  

2008
Natalia V. Pogodina Claire Cerclé Luc Avérous Ralph Thomann Michel Bouquey René Muller

Nanobiocomposites of poly(lactic acid) (PLA) with 3–5 wt% organically modified montmorillonite (OMMT) were prepared by melt compounding in two different mixers, miniature twin-screw extruder and internal batch mixer, leading to different degrees of dispersion. The progress of dispersion was characterized by melt rheology coupled with light attenuation. Processed PLA/OMMT samples showed percolat...

2015
Yuya Nakamura Seiji Tomiguchi Masayuki Tanaka

BACKGROUND Generally, attenuation correction is made by incorporating a linear attenuation coefficient, which is based on the attenuation coefficient map (mu-map) created from a computed tomography scan, into the ordered subsets-expectation maximization reconstruction method in non-uniform domains. A non-uniform Chang's attenuation correction method that uses the mu-map created from a computed ...

2006
Eugenio Gorgucci Luca Baldini

Although is not a major error source at C-band, attenuation may degrade the radar measurement to a considerable degree in situations like a precipitation event in the radar shadow of a strong convective cell, or may affect precipitation accumulation estimates at distances far from the radar site. For C-band radars, attenuation can be corrected using different methods depending on the type of me...

Journal: :The Eurasian journal of medicine 2010
M Erdem Sagsoz Fazlı Erdogan Salih Z Erzeneoglu İhsan Yuce

OBJECTIVE X-ray attenuation coefficients are used in common radiological, pathological and spectroscopic examinations and in the determination of the radiation dose distribution in biological tissues. In radiology, these coefficients enable diagnosis by differentiating the abnormal tissues from the normal ones using their morphological structure and contrast differences. In this study, our aim ...

2013
Ali Basheer Azeez Kahtan S. Mohammed Mohd Mustafa Al Bakri Abdullah Kamarudin Hussin Andrei Victor Sandu Rafiza Abdul Razak

Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137Cs and ⁶⁰Co radioactive elements with photo...

Azim Arbabi Hossein Masoumi Manijeh Mokhtari-Dizaji Mohsen Bakhshandeh

Background & Aims: Today, different imaging techniques have been studied in the reading of radiationsensitive polymer gels dosage. Due to limitations of imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT), ultrasound techniques are proposed for dose-dependent parameter extraction. In this study, using MAGIC-f (methacrylic and ascorbic acid in gelatin initiat...

Journal: :Physical review letters 2011
A Baron S Mazoyer W Smigaj P Lalanne

It is widely accepted that, on ensemble average, the transmission T of guided modes decays exponentially with the waveguide length L due to small imperfections, leading to the important figure of merit defined as the attenuation-rate coefficient α=-⟨ln(T)⟩/L. In this Letter, we evidence that the exponential-damping law is not valid in general for periodic monomode waveguides, especially as the ...

2013
S. N. Khan R. M. Warkhedkar B. R. Patil

Bone mineral density [BMD] generally correlates with bone strength. BMD testing is used to assess bone density and diagnose osteoporosis. The HU scale is a linear transformation of the original linear attenuation coefficient measurement in to one in which the radio-density of distilled water at standard pressure and temperature is defined as Zero Hounsfield Unit while the radio-density of air a...

2003
John T. O. Kirk Kirk Marine

Average vertical attenuation coefficients, K(av), for irradiance calculated by linear regression of ln E(z) on z through the euphotic zone or from two irradiance values in a certain depth interval, are useful but somewhat arbitrary procedures for estimating these important apparent optical properties of the ocean. A more fundamental approach is to calculate an irradiance-weighted coefficient, K...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 1992
L P Clarke S J Cullom R Shaw C Reece B C Penney M A King M Silbiger

Quantitative imaging of bremsstrahlung from pure beta emitters is proposed as a means for in vivo management of antibody therapy. The method involves the use of high-energy collimation, an empirically selected broad photon energy window to enhance detector sensitivity, and a Wiener restoration filter to compensate for system blur. The measured and filtered data were obtained for an idealized sc...

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