Radiation defects parameters determination in n-Ge single crystals irradiated by high-energy electrons

Hall effect for single crystals of n-Ge, irradiated by various streams of electrons with an energy of 10 MeV is investigated. Taking into account the experimental results, the energy spectrum of radiation defects is found and their parameters are established. On the basis of solutions of electroneutrality equations systems, it is shown that the created radiation defects correspond to only two deep energy levels (Ec - 0.27) eV and (Ec + 0.27) eV. A slight change of energy position of these levels with irradiation dose increasing can be explained by internal mechanical stresses influence that arise in the germanium lattice around created radiation defects

ПАТОГЕНЕТИЧНІ МЕХАНІЗМИ ТА ФАКТОРИ РИЗИКУ ВЗАЄМООБТЯЖЕННЯ ХРОНІЧНОГО ХОЛЕЦИСТИТУ, ХОЛЕСТЕРОЗУ ЖОВЧНОГО МІХУРА ІЗ ОЖИРІННЯМ ТА ІШЕМІЧНОЮ ХВОРОБОЮ СЕРЦЯ

The article presents the pathogenic mechanisms of the relationship between the development of chronic cholecystitis, gallbladder cholesterosis in patients with obesity and ischemic heart disease based on substantial lipid imbalance. It has been shown that endothelial dysfunction resulting from disturbance of structural and functional properties of the endothelium plays a significant part in the pathogenesis of coronary heart disease and leads to disordess of local regulation of vascular tone. The role of nitrosative and oxidative stress as a trigger in the development and progression of chronic cholecystitis and gallbladder cholesterosis in patients with ischemic heart disease and obesity is elucidated.В статье приведены патогенетические механизмы взаимосвязи между развитием хронического холецистита, холестероза желчного пузыря у лиц с ожирением и ишемической болезнью сердца на основании существенного липидного дисбаланса. Показано, что существенную роль в патогенезе ишемической болезни сердца играет эндотелиальная дисфункция, возникающая вследствие нарушения структурно-функциональных свойств эндотелия и приводит к расстройствам местной регуляции тонуса сосудов. Освещена роль нитрозитивного и оксидативного стресса в качестве пусковых механизмов в развитии и прогрессировании хронического холецистита и холестероза желчного пузыря у больных ишемической болезнью сердца и ожирением.У статті наведено патогенетичні механізми взаємозв’язку між розвитком хронічного холециститу, холестерозу жовчного міхура в осіб з ожирінням та ішемічною хворобою серця  на підставі істотного ліпідного дисбалансу. Показано, що істотну роль у патогенезі ішемічної хвороби серця  відіграє ендотеліальна дисфункція, яка виникає внаслідок порушення структурно-функціональних властивостей ендотелію і призводить до розладів місцевої регуляції тонусу судин. Висвітлена роль нітрозитивного та оксидативного стресу як пускових механізмів у розвитку та прогресуванні хронічного холециститу та холестерозу жовчного міхура у хворих на ішемічну хворобу серця  та ожиріння

Determination of the activation energy of A-center in the uniaxially deformed n-Ge single crystals

Based on the decisions of electroneutrality equation and experimental results of measurements of the piezo-Hall-effect the dependences of activation energy of the deep level A-center depending on the uniaxial pressure along the crystallographic directions [100], [110] and [111] for n-Ge single crystals, irradiated by the electrons with energy 10 MeV are obtained. Using the method of least squares approximational polynomials for the calculation of these dependences are obtained. It is shown that the activation energy of A-center deep level decreases linearly for the entire range of uniaxial pressure along the crystallographic direction [100]. For the cases of uniaxial deformation along the crystallographic directions [110] and [111] decrease of the activation energy according to the linear law is observed only at high uniaxial pressures, when the A-center deep level interacts with the minima of the germanium conduction band, which proved the lower at the deformation. The various dependences of the activation energy of A-center depending on the orientation of the axis of deformation may be connected with features of its microstructure

Presence of Oxygen in Ti-Al-C MAX Phases-Based Materials and their Stability in Oxidizing Environment at Elevated Temperatures

International audienceThe Ti3AlC2-, (Ti,Nb)3AlC2- and Ti2AlC-based materials turned out to be more resistant than Crofer JDAsteel in oxidizing atmosphere as 1000 h long tests at 600◦C have shown. But the amounts of oxygen absorbed bythe materials during testing were different. The Ti2AlC-based material demonstrated the lowest oxygen uptake,(Ti,Nb)3AlC2-based absorbed a somewhat higher amount and the highest amount was absorbed by Ti3AlC2-basedmaterial. Scanning electron microscopy and the Auger study witnessed that amounts of oxygen in the MAXphases before the exposure in air were as well different: the approximate stoichiometries of the matrix phases ofmaterials were Ti3.1−3.2AlC2−2.2, Ti1.9−4Nb0.06−0.1AlC1.6−2.2O0.1−1.2and Ti2.3−3.6AlC1−1.9O0.2−0.6, respectively.The higher amount of oxygen present in the MAX phase structures may be the reason for higher resistanceto oxidation during long-term heating in air at elevated temperature. The studied materials demonstrated highstabilities in hydrogen atmosphere as well. The bending strength of the Ti3AlC2- and (Ti,Nb)3AlC2-based materialsafter keeping at 600◦C in air and hydrogen increased by 10–15%, but the highest absolute value of bending strengthbefore and after being kept in air and hydrogen demonstrated the Ti2AlC-based material (about 590 MPa)

Presence of Oxygen in Ti-Al-C MAX Phases-Based Materials and their Stability in Oxidizing Environment at Elevated Temperatures

The Ti₃AlC₂-, (Ti,Nb)₃AlC₂- and Ti₂AlC-based materials turned out to be more resistant than Crofer JDA steel in oxidizing atmosphere as 1000 h long tests at 600°C have shown. But the amounts of oxygen absorbed by the materials during testing were different. The Ti₂AlC-based material demonstrated the lowest oxygen uptake, (Ti,Nb)₃AlC₂-based absorbed a somewhat higher amount and the highest amount was absorbed by Ti₃AlC₂-based material. Scanning electron microscopy and the Auger study witnessed that amounts of oxygen in the MAX phases before the exposure in air were as well different: the approximate stoichiometries of the matrix phases of materials were Ti_{3.1-3.2}AlC_{2-2.2}, Ti_{1.9-4}Nb_{0.06-0.1}AlC_{1.6-2.2}O_{0.1-1.2} and Ti_{2.3-3.6}AlC_{1-1.9}O_{0.2-0.6}, respectively. The higher amount of oxygen present in the MAX phase structures may be the reason for higher resistance to oxidation during long-term heating in air at elevated temperature. The studied materials demonstrated high stabilities in hydrogen atmosphere as well. The bending strength of the Ti₃AlC₂- and (Ti,Nb)₃AlC₂-based materials after keeping at 600°C in air and hydrogen increased by 10-15%, but the highest absolute value of bending strength before and after being kept in air and hydrogen demonstrated the Ti₂AlC-based material (about 590 MPa)