Employing Dynamic Discrete Dislocation Plasticity (D3P), an elastodynamic analysis of the shielding of a stationary crack tip by dislocations is studied. Dislocations are generated via FrankRead sources, and make a negligible contribution to the shielding of the crack tip, whereas dislocations generated at the crack tip via homogeneous nucleation dominate the shielding. Their effect is found to...

hartree-fock (hf) and density functional theory (dft) methods employed to study the effect of conformational change on the 13c chemical shifts of 6-mono axial and equatorial substituted and 6,7-di axial-axial, equatorial-equatorial and axial-equatorial substitutedderivatives of 5,6,7,8-tetrahydrodibenzo[a,c]cyclo-octene. the geometry of the conformers have been optimized in the gas phase employ...

the interaction of dppa which is an important component in cellular membrane with molecules of water asmedia, cause some changes in geometry of dppa .in this study we focused our attention on comparing thismolecule with related hydrated complexes employing different basis sets at hartree-fock levels of theory. thetheoretical nmr shielding tensor of some imported atoms were also reported.

G. Fehrenbacher, F. Gutermuth, T. Radon GSI Darmstadt, Germany An important aspect to be considered when designing the GSI future project will be the radiation protection of both the staff and the environment. One of the prerequisites for a permission for the operation of a high-energy accelerator is a careful planning of the necessary radiation shielding equipment. In order to give recommendat...

Shielding effects of a nanocage can be determined by the field felt by an encapsulated noble gas (NG) atom. Using the polarizability distributions about NG endohedral fullerenes (NGEFs), a new scheme based on the local polarizability of the NG is introduced to detect the shielding effects of fullerenes, using density functional theory calculations and Hirshfeld population analysis. For large ca...

The requirements for shielding a treatment vault with a Varian Clinac 2100 medical linear accelerator operated both with and without the flattening filter were assessed. Basic shielding parameters, such as primary beam tenth-value layers (TVLs), patient scatter fractions, and wall scatter fractions, were calculated using Monte Carlo simulations of 6, 10 and 18 MV beams. Relative integral target...

in this research, we studied the structure, properties and nmr parameters of interaction f2 gas with pristine and 3c-doped (8, 0) zigzag models of boron phosphide nanotubes (bpnts). in order to reach these aims, we considered four different configurations for adsorption of f2gas on the outer and inner surfaces of bpnts. the structures of all models were optimized by using density functional the...

In the discussion that follows, we assume that gamma rays are the radiation of interest. The principles discussed also apply to monoenergetic x rays; in many cases of concern in x-ray shielding, however, the photons are produced in the bremsstrahlung process that yields a wide and continuous distribution of photon energies. Specialized shielding approaches have been developed to carry out shiel...

In the treatment of superficial lesions with 8-13 MeV electrons, lead shields are often used to protect the underlying tissue. Measurements were made with film and ion chamber to analyse various aspects of external and internal shielding in electron beam therapy. Data were obtained on the thickness of lead required for shielding, the effect of blocking on dose-rate, electron-backscattering from...

2014 Superconducting shields offer the possibility of obtaining truly zero magnetic fields due to the phenomenon of flux quantization. They also offer excellent shielding from external time varying fields. Various techniques of superconducting shielding will be surveyed and recent results discussed. REVUE DE PHYSIQUE APPLIQUÉE: TOME 5, FÉVRIER 1970, PAGE