In this paper, we present the shielding analysis to determine the necessary neutron and photon shielding for a laser-accelerated proton therapy system. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. A special particle selection and collimation devic...

Ring currents can exert a large effect upon the chemical shielding of NMR resonances. The analytical expression developed by Waugh and Fessenden (Waugh, J. S.; Fessenden, R. W. J. Am. Chem. Soc. 1957, 79, 846) and Johnson and Bovey (Johnson, C. E.; Bovey, F. A. J. Chem. Phys. 1957, 29, 1012) only quantifies the contribution of ring currents to the isotropic component of the shielding tensor. In...

We investigate the nature of higher-order effects arising in solid-state nuclear magnetic resonance ~NMR! when quadrupolar nuclei are subject to significant chemical shift anisotropies. It is shown that the quadrupole interaction can give rise to shielding-derived terms that are not entirely averaged away by conventional magic-angle spinning ~MAS!. These terms are proportional to the square of ...

The longitudinal proton relaxation time Tt of aqueous solutions of bovine ferrihemoglobin and carboxilated hemoglobin was measured in the Larmor frequency range 3-103 Hz to 1,2 -108 Hz. The dispersion curves are explained by diamagnetic and electron paramagnetic relaxation mechanisms. An efficient direct dipolar coupling between the paramagnetic heme-groups and the water protons in ferrihemoglo...

Ferromagnetic rods containing thin sections of diamagnetic metal create intense magnetic field gradients that attract and confine magnetic nanoparticles to regions of space as small as 20 nm. The rods (80 nm diameter) comprised alternating sections of CoNi ( approximately 350 nm) and Au (20-160 nm) formed by electrodeposition into porous polycarbonate membranes. Upon magnetizing the rods, large...

Abstract: At the micro-scale, diamagnetic effects are of the same order of magnitude or even stronger than weight. Therefore, micro-magnets can levitate above diamagnetic bodies and move freely in the three dimensions of space. The possibilities and limits of a static and permanent levitating magnet are illustrated for the example of a 3-dimensional micro-accelerometer. Optimization is performe...

T1 relaxation time sufficient to produce pallidal T1 hyperintensity in hepatolenticular degeneration. [4] Manganese is also used as MR contrast due to the above properties but surprisingly SWI failed to show any blooming. Interestingly, calcification containing diamagnetic calcium is visualized in SWI and hence is used in the seizure MR imaging protocol.[5] The magnetic susceptibility of parama...

background: designing and shielding of an appropriate radiography room has been one of the major concerns of radiation scientists since the first decade after the invention of x-rays. recently, report no.147 of national council on radiation protection and measurements (ncrp) has been published. in this study the researchers have investigated the effect of new report recommendation on primary an...

The long-held “shielding cone” model of the through-space NMR shielding effect of a carbon-carbon double bond predicts only the effect of the magnetic anisotropy of the double bond; it ignores other important contributors to the overall shielding. GIAO-SCF and GIAO-MP2 calculations have been performed on a simple model system, methane moved sequentially above ethene or 2-methylpropene. These ca...

The effect of material type, yarn count, pick density, type of mordant and layers of fabrics on the electromagnetic shielding properties of textile materials has been studied. The shielding effectiveness of the fabric is measured by estimating the insertion loss incurred to the signal when the sample is placed in the path of the signal at the frequency range 100 MHz-3 GHz inside the coaxial tra...