An analysis is made of the charge distribution in a quasi-static thundercloud system with the assumptions that (1) the cloud has a charge separation mechanism at its midpoint and ( 2 ) the conductivity within the cloud is reduced by a given fraction from the free-air conductivity remote from the storm. The charge separation mechanism produces the primary positive dipole of the storm. The analys...

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...

Cationic polymers are promising components of the versatile platform of non-viral nucleic acid (NA) delivery agents. For a successful gene delivery system, these NA vehicles need to comprise several functionalities. This work focuses on the modification of oligoaminoamide carriers with hydrophilic oligomer blocks mediating nanoparticle shielding potential, which is necessary to prevent aggregat...

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 ...

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...

Background: We sought to characterize humeral-sided radiographic changes at a minimum of 2 years after reverseshoulder arthroplasty (RSA) to determine their association with specific implantation techniques.Methods: The immediate and most recent postoperative anteroposterior radiographs of 120 shoulders with primary RSAand a minimum of 2-years of radiographic follow-up were an...

Extra high voltage (EHV) substations are extremely vulnerable to the hazard of lightning strokes therefore, the shielding of these substations with a highly reliable protective scheme (shield wires) is an essential undertaking. In this paper an attempt is made to clarify the design procedure for shielding EHV substations against lightning with special reference to Iran.

An historical review of the development of shielding techniques for indirectly ionizing radiation is presented, along with a summary of techniques at various levels of sophistication for shielding design and analysis.

for superficial lesions, the electrons may be used for radiation therapy. the high energy photons and electrons are produced by a linear accelerator (linac).   many of electron fields need the shielding of normal or critical organs. the electron shields are usually lead slabs with few millimeter thickness which should be placed near the skin, less than 1 centimeter away from skin. in the inspec...

The Ir-Fe and Ir-Ni alloy systems were studied over the whole composition range by means of the nuclear resonance absorption of the 73 keV y-rays of 193Jr and of the 14.4 keV y-rays of 57Fe. The magnetic hyperfine field at the Ir-nuclei in Ir-Ni alloys decreases approximately linearly with the Ir concentration from — 460 kOe at 4.2 K in very dilute alloys to zero at about 20 at.-% Ir. This beha...