The effect of silver doping on the microstructure and transport properties of the YBCO bulk system have been investigated through scanning electron microscopy observation, resistivity and susceptibility measurements, including the critical current density. We have used the additive method for the YBCO system (0.01-60 wt% of Ag). The results of the structural and superconductivity properties show that silver doping has no noticeable effect on the T c of samples, but influences the samples' J c , which increases with increasing silver doping content up to 20 wt% for the YBCO system. The intergranular T c (detected by the imaginary parts of the susceptibility) improved in the doped samples up to the 20 wt% Ag. It was found that excess metallic Ag filled the pores of the bulks and encouraged the formation of larger stacks of flat rectangular platelets, resulting in a c-axis preferred orientation.

The modified Kratzer potential for the two limiting cases of interest of the interactions is investigated. The corresponding solutions of the bound states of the Schrödinger equation are studied. Moreover, we use this approximation to obtain the solution of the Schrödinger equation for the Morse potential and the results are compared with one another.

Due to the physical and chemical processes that are involved, interactions of ionizing radiations with cells lead to single-and double-strand breaks (SSB and DSB) and base damage to DNA cells. The damage may kill the cells or may be mis-repaired and lead to genetic diseases and cancers. Track structure Monte Carlo simulation of the DNA damage provides types of the damage and their frequencies. In the present work, to derive initial DNA damage, we used the Geant4-DNA code to simulate the physical, physico-chemical and chemical stages of interactions of incident beams of 100 eV-4.5 keV electrons. By considering the direct damage of electrons and also the indirect hydroxyl radical damage to the DNA, in a simulation, simple and complex damages to SSB and DSB were investigated. Moreover, the yield of damage and the probability of types of DNA damage were evaluated. The results of these calculations were compared with the existing experimental data and the other simulations. For electrons with energies lower than 500 eV, there were differences between our results and published data which are basically due to the existing differences in the physical (electron ionization, excitation cross sections) and chemical models of Geant4-DNA, the chemical processes considered in the simulations, DNA geometry, and the selected parameters for damage threshold as compared to the other codes. In the present work, the effect of the threshold energy of the strand breaks was also evaluated.

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