نتایج جستجو برای: shielding materials

تعداد نتایج: 444083  

Journal: :Physical chemistry chemical physics : PCCP 2013
Wenying Shi Yanjun Lin Shitong Zhang Rui Tian Ruizheng Liang Min Wei David G Evans Xue Duan

The development of UV-shielding materials has attracted considerable attention in the field of coatings and sunscreen. This paper reports the UV-shielding mechanism of layered double hydroxide (LDH) materials in terms of chemical composition, structure and morphology, by using (LDH/PAA)n films (n stands for bilayer number) through alternate LBL assembly of LDH nanoparticles and poly(acrylic aci...

Journal: :Journal of the Surface Finishing Society of Japan 1991

Introduction: Unwanted exposure of ionizing radiation may result in carcinogenesis, cell mutations, and organ failure. High-atomic number elements such as lead, tungsten, bismuth have been traditionally used for radiation protection. Theoretical and practical studies have shown that a variety of shielding materials e.g. polymer composites (PCs) can be used for attenuation of th...

Journal: :Medical physics 1998
B R Paliwal S Rommelfanger R K Das

A new thermoplastic material with extremely desirable physical and radiation shielding properties is presented. The material softens between 108 degrees F and 132 degrees F and can then be easily molded to any desired shape. As it cools down it hardens at about 102 degrees F, retaining its molded shape. It is very light (rho = 1.66 g/cc), compared to most other compensating and shielding materi...

2010
C. D. Raj G. S. Rao P. V. Y. Jayasree B. Srinu P. Lakshman

Electromagnetic shields are designed to optimize the performance for shielding effectiveness and reflectivity. Multilayered laminates of different materials are developed to achieve excellent results in terms of not only in shielding effectiveness but also for reflectivity. In this paper, a three layered laminate is considered for estimation of the required parameters in the X-band frequency ra...

Journal: :Health physics 1995
J W Wilson M Kim W Schimmerling F F Badavi S A Thibeault F A Cucinotta J L Shinn R Kiefer

When shielding from cosmic heavy ions, one is faced with limited knowledge about the physical properties and biological responses of these radiations. Herein, the current status of space shielding technology and its impact on radiation health is discussed in terms of conventional protection practice and a test biological response model. The impact of biological response on optimum materials sel...

2013
Petre Ogruţan Lia Elena Aciu

The theory of electromagnetic shielding is based on the waves equations describing the behavior of electromagnetic field in material. The proposed approach consist in a PSpice model using transmission line model to simulate the attenuation introduced by a material characterized by the macroscopic parameters ε, μ, σ. To verify the data obtained through PSpice simulation, a wave-guide-based measu...

2012
M. Boyvat C. Hafner

In this paper, it is demonstrated how anisotropic and inhomogeneous magnetic metamaterials may be used for molding the flow of the magnetic field, considering magnetic field shielding as the main application of practical interest. It is shown that using anisotropic materials, magnetic field shielding may be improved, and this anisotropy can be realized by metamaterials. Introducing additional i...

2007
Pavel Steffan Jiri Stehlik Radimír Vrba

This paper demonstrates that the addition of chemical agents and carbon fibers to cement can greatly enhance the shielding effectiveness of the concrete. In addition to improving the shielding effectiveness, carbon fibers and chemical agents enhance the tensile and flexural strengths significant ly. As both carbon fibers and steel fibers are electrically conductive, both can be added to cement ...

Journal: :Medical physics 2007
J P McCaffrey H Shen B Downton E Mainegra-Hing

The attenuating properties of several types of lead (Pb)-based and non-Pb radiation shielding materials were studied and a correlation was made of radiation attenuation, materials properties, calculated spectra and ambient dose equivalent. Utilizing the well-characterized x-ray and gamma ray beams at the National Research Council of Canada, air kerma measurements were used to compare a variety ...

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