نتایج جستجو برای: attenuation coefficient

تعداد نتایج: 216100  

2015
D. L. Aksnes

The critical depth concept was first recognized by Gran and Braarud (1935). During summer, in the Bay of Fundy, they observed an unexpected no bloom situation. Their interpretation was that high amounts of detritus of terrestrial origin caused too murky water and insufficient light for the tidallymixedphytoplankton. Almost 20 years later, thiswas elaboratedby Sverdrup (1953) into ahypothesis fo...

Journal: :Medical physics 2009
B Heismann M Balda

Computed tomography (CT) devices are routinely employed to obtain three-dimensional images of the human body. The reconstructed CT numbers represent weighted x-ray attenuation coefficients. Their spectral weighting is influenced by the selected x-ray source spectrum, the detector characteristics, and the attenuating object itself. The quantitative ground truth of the scanned object is given by ...

2013
P. Limkitjaroenporn

Citrine is a transparent gemstone, yellow microcrystalline quartz variety. Natural citrine is very rare and will actually lose its color upon heating to more than 200°C, and the yellow color will occur again when the crystal is irradiated with Xor gamma-rays, indicating that attenuation parameters is important to enhancements by irradiation. In this work, the mass attenuation coefficients of ci...

Introduction: Investigation of radiation interaction with living organs has always been a thrust area in medical and radiation physics. The investigated results are being used in medical physics for developing improved and sensitive techniques and minimizing radiation exposure. In this study, mass attenuation coefficients of different human organs and biological materials such as adipose, blood...

2017
W A M Wanniarachchi P G Ranjith M S A Perera T D Rathnaweera Q Lyu B Mahanta

The mechanical properties of any substance are essential facts to understand its behaviour and make the maximum use of the particular substance. Rocks are indeed an important substance, as they are of significant use in the energy industry, specifically for fossil fuels and geothermal energy. Attenuation of seismic waves is a non-destructive technique to investigate mechanical properties of res...

A. Taherkhani, M. Mohammadi, M.S. Saboori, V. Changizi,

Background: In Radiation Therapy, the sparing of normal tissues can be performed using either multi-leaf collimators or Cerrobend blocks. The current work focuses on the physical characteristics of Cerrobend blocks including attenuation coefficient, effective penumbra width and isodose curves undulation in penumbral regions. Materials and Methods: All measurements were performed using ...

Introduction: Phantom is an object that can be used to investigate the accuracy of radiation dose delivered to patients. Phantom is usually produced from the combination of the silicone rubber as a matrix and glycerin as a filler to form a composite for the replacement of the human soft tissue. The composite is imaged using computed tomography (CT) simulator for the de...

Journal: :Universal Journal of Electrical and Electronic Engineering 2017

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