Effect of argon annealing method on structural and ferromagnetic properties in Fe-doped SnO2 powders

Nanocrystalline powders of Fe-doped SnO2 (Sn1-xFexO2) (x = 0.00, 0.01, 0.03, 0.05) were prepared by a hydrothermal method. The powders were calcined in argon atmosphere at 600 °C for 2 h, causing phase transition from diamagnetic and weak ferromagnetic behavior to a ferromagnetic state. No trace and other magnetic impurity phases was detected in the samples with Fe content up to 3%. The calcined samples of Fe-doped SnO2 revealed the room temperature ferromagnetism with highest magnetization values of 434.07 memu/g at 15 kOe for x = 0.05. The room temperature ferromagnetism of samples originated from oxygen vacancies that occurred in the argon calcination process. In particular, oxygen vacancy shows a significant role in ferromagnetic coupling corresponding to F-center interaction.

Structural optimization of silicon thin film for thermoelectric materials

The method to optimize nanostructures of silicon thin films as thermoelectric materials is developed. The simulated annealing method is utilized for predicting the optimized structure. The mean free path and thermal conductivity of thin films, which are the objective function of optimization, is evaluated by using phonon transport simulations and lattice dynamics calculations. In small systems composed of square lattices, the simulated annealing method successfully predicts optimized structure corroborated by an exhaustive search. This fact indicates that the simulated annealing method is an effective tool for optimizing nanostructured thin films as thermoelectric materials.

Optimization of Phase Determining Method for Automatic Transfer Switch Operation Based on Simulated Annealing

Fast reserve supply input systems significantly increase the reliability of power supply due to the possibility of preserving the technological process in case of emergency situations. The accuracy of determining the phase of the residual voltage on the busbar in process of connecting the power reserve supply provides a way to significantly reduce the starting overcurrents. In this paper, some modifications of the annealing method for determining the phase of the residual voltage on main section of busbar for emergency mode are considered. The obtained simulation results based on MATLAB environment make it possible to carry out a comparative analysis of a number of calculations for phase estimation design of automatic transfer switch operations based on simulated annealing.

Application of Evolutionary Simulated Annealing Method to Design a Small 200 MWt Reactor Core

This paper presents the application of an evolutionary simulated annealing (ESA) method to design a small 200 MWt reactor core. The core design is based on a reference ACPR50 reactor deployed in a floating nuclear power plant. The core consists of 37 typical 17x17 PWR fuel assemblies with three different U-235 enrichments of 4.45, 3.40 and 2.35 wt%. Core loading pattern (LP) has been optimized for obtaining the cycle length of 900 effective full power days, while minimizing the average U-235 enrichment and the radial power peaking factor. The optimization process was performed by coupling the ESA method with the COREBN module of the SRAC2006 system code.