نتایج جستجو برای: shielding materials
تعداد نتایج: 444083 فیلتر نتایج به سال:
This study indicated that multi-walled carbon nanotubes (MWCNTs)-epoxy composites can be used as effective lightweight shielding materials. The measurement results showed that highest EMI SE of 23.4 dB at 8 GHz was obtained for nanocomposite with 1 wt% MWCNTs. Dielectric properties and electrical conductivity values were supplemented by microscopic studies.
Background: The Shielding methods in radiotherapy due to delivering an accurate radiation dose to cancer tissues and avoiding unnecessary dose to normal tissues are very important. These methods include Lead standard blocks, individual molding and multi leaf collimator (MLC). The MLC method is not still common in Iran radiotherapy centers. Individual molding is better than the lead block shield...
Utilizing a multilayered composite approach, we have designed and constructed a new class of artificial materials for thermal conduction. We show that an engineered material can be utilized to control the diffusive heat flow in ways inconceivable with naturally occurring materials. By shielding, concentrating, and inverting heat current, we experimentally demonstrate the unique potential and th...
PURPOSE High-radiation exposure occurs during computed tomographic (CT) fluoroscopy. Patient and operator doses during thoracic and abdominal interventional procedures were studied in the present experiment, and a novel shielding device to reduce exposure to the patient and operator was evaluated. MATERIALS AND METHODS With a 16-slice CT scanner in CT fluoroscopy mode (120 kVp, 30 mA), surfac...
Proton therapy accelerators have become increasingly popular for cancer treatment in recent years. In Taiwan, the first proton treatment center equipped with a 235 MeV proton cyclotron in Linkou Chang Gung Memorial Hospital is ready for beam commissioning. Proton therapy accelerators in the energy range could potentially produce intense secondary neutrons, which must be carefully evaluated and ...
As NASA is looking to explore further into deep space, multifunctional materials are a necessity for decreasing complexity and mass. One area where multifunctional materials could be extremely beneficial is in the micrometeoroid orbital debris (MMOD) shield. A typical MMOD shield on the International Space Station (ISS) is a stuffed whipple shield consisting of multiple layers. One of those lay...
The paper describes recent advances in the modelling and simulation of materials and screens for the shielding and absorption of EM waves. Simple intermediate models are briefly outlined, followed by models for describing complex materials and screens in the time-domain.
Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative t...
BACKGROUND The aim of the study was to determine the influence of lead shielding on the dose to female breasts in conventional x-ray lumbar spine imaging. The correlation between the body mass index and the dose received by the breast was also investigated. MATERIALS AND METHODS Breast surface dose was measured by thermoluminescent dosimeters (TLD). In the first phase measurements of breast d...
Nanoscale ordering in a polymer blend structure is indispensable to obtain materials with tailored properties. It was established here that controlling the arrangement of nanoparticles, with different characteristics, in co-continuous PC/PVDF (polycarbonate/poly(vinylidene fluoride)) blends can result in outstanding microwave absorption (ca. 90%). An excellent reflection loss (RL) of ca. -71 dB...
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