نتایج جستجو برای: shields

تعداد نتایج: 2969  

Journal: :Gold Bulletin 1972

Journal: :Indian Journal of Ophthalmology 2019

A. Aghaz, A. Haghparast, R. Faghihi, S. Mehdizadeh, S. Sina, S.M.J. Mortazavi,

Background: It has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. Over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. The purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-...

Introduction: This study introduces a novel polyvinyl chloride (PVC)/tungsten composites with characterization of their shielding properties by employing different techniques. Methods: The PVC/tungsten composites were produced by employing various weight fractions of tungsten micro-particles including 0, 20, and 40 % wt via melt blending method. In the next st...

Journal: :Informes de la Construcción 1958

Journal: :iranian journal of radiology 0
ayoub momivand urmia university of medical sciences, iran; urmia university of medical sciences, iran

conclusions available shields for the thyroid and eyes should be implemented in clinical practice. further research is needed to demonstrate the prevalence of shielding in the clinical setting. results only a limited number of studies have been performed on the use of shields for the eyes and thyroid, but the evidence shows an overall benefit to their use. this study demonstrates how thyroid sh...

Journal: :iranian journal of radiation research 0
s.m.j. mortazavi department of medical physics and medical engineering, and the center for research in radiation sciences (crrs), shiraz university of medical sciences, shiraz, iran m. kardan nuclear science and technology research institute, tehran, iran s. sina department of nuclear engineering, school of mechanical engineering, shiraz university, shiraz, iran h. baharvand department of polymer chemistry, iran polymer institute, tehran, iran n. sharafi department of radiology, school of paramedical sciences, shiraz university of medical sciences, shiraz, iran

background: polyethylene composites including boron can be used as an effective neutron shield. our investigation focuses on manufacturing borated polyethylene nano-composite. the purpose of this study is to design a radiation shield for use in both neutron and gamma fields. materials and methods: borated polyethylene shields containing 2%, and 5% weight percentage of boron nano-particles were ...

Journal: :iranian journal of radiation research 0
a. aghaz nuclear engineering department, shiraz university, shiraz, iran r. faghihi nuclear engineering department, shiraz university, shiraz, iran s.m.j. mortazavi medical physics department and the center for research on radiological sciences, shiraz university of medical sciences, shiraz, iran a. haghparast medical physics department, kermanshah university of medical sciences, kermanshah, iran s. mehdizadeh radiation research center, shiraz university, shiraz, iran s. sina radiation research center, shiraz university, shiraz, iran

background: it has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. the purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-...

2003
JOHN HOLLIDAY PETER JOHNSON P. JOHNSON

The Shields-Harary numbers are a class of graph parameters thatmeasure a certain kind of robustness of a graph, thought of as a network of fortified reservoirs, with reference to a given cost function. We prove a result about the Shields-Harary numbers with respect to concave continuous cost functions which will simplify the calculation of these numbers for certain classes of graphs, including ...

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