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Mechanically Stimulated Changes in Surface Electrical Conductivity of X-Irradiated Silicon Crystals

Lys Roman, Żyłka Marta, Shykorjak Josyp, Slobodzyan Dmytro, Żyłka Wojciech, Pavlyk Bohdan

Advances in Science and Technology. Research Journal

2023

Vol. 17, no 2

226--231

Changes in the resistance of single crystals of p-type conductivity silicon under the action of mechanical loading were investigated in this research. Also, non-irradiated and pre-irradiated X-rays experimental samples were studied. It was found that at small deformation values when they are at the initial stage of the action of elastic deformation, a section forms and increases, on which the resistance practically does not depend on the applied mechanical load. In irradiated crystals, at small deformation values, electron generation processes dominate, which then recombine with the main carriers – holes. The consequence of such processes is the appearance of a maximum increase in electrical resistance at the initial stage of elastic deformation of experimental samples irradiated with X-rays. Charge carrier generation processes begin to dominate with further deformation. Such processes occur as a result of the release of acceptor centers from other complex defects, which are destroyed during the deformation of the Si crystal and captured by mobile dislocations. Thus, the processes of generation of charge carriers prevail over the processes of gettering and, accordingly, a mechano-stimulated decrease in the electrical resistance of p-Si samples occurs.

The influence of X-rays on strength properties of polyester vascular system prosthesis

Rojek M., Stabik J.

Journal of Achievements in Materials and Manufacturing Engineering

2009

Vol. 35, nr 1

47-54

Purpose: of this paper was to evaluate the influence of X-ray irradiation on mechanical properties of polyester yarn used in production of vascular system prosthesis. Patients with such prosthesis are subjected to multiple X-ray radioscopic exposures. This can negatively influence prosthesis strength and durability. Design/methodology/approach: Polyester yarn tensile strength properties were measured before sterilisation and X-ray irradiation. Next a part of yarn was subjected to irradiation sterilisation. Sterilised and non-sterilised yarn was next exposed to multiple X-ray irradiation and to continuous irradiation. After each irradiation dose tensile strength and elongation at break were measured. Findings: The influence of X-ray irradiation dose on mechanical properties was evaluated. It was established that dose equivalent to multiple X-ray radioscopic exposures did not substantially influenced strength properties of polyester yarn. Research limitations/implications: To fully evaluate the influence of X-ray irradiation on prosthesis strength and durability working in human body environment it is planned to continue described research. Simultaneous influence of X-ray irradiation and body fluids on mechanical properties of polyester yarn will be tested. Practical implications: Research results proved that patients with polyester vascular prosthesis may be subjected to X-ray radioscopy without any anxiety concerning prosthesis strength properties or durability. Originality/value: The main research value is its basic conclusion that multiple X-ray irradiation does not significantly influence strength and flexibility of polyester yarn applied to vascular system prosthesis manufacture.