Seminar khoa học

9.00 AM - 10.00 AM:  Dr. Nguyen Hoang Son (INCOS, TDTU)  presents the topic: "A novel hr-adaptive mesh refinement scheme for stress-constrained topology optimization using level-set-based trimmed meshes"

Abstract:

An octree-based h-adaptive mesh refinement using a stress-based criterion is performed to dynamically refine or coarsen an initial uniform background hexahedral mesh during the optimization process. In order to estimate stresses and shape sensitivities accurately on the domain boundaries, an r-adaptive boundary-conforming trimmed hexahedral mesh is generated by cutting the background octree mesh with the zero-isosurface of a level-set function. The numerical results show that the proposed hr-adaptive mesh refinement scheme greatly reduces the computational cost and achieves a clear and explicit representation of desired optimal designs of structures with stress constraints.

10.00 AM – 11.00 AM:  Dr. Le Thi Cam Tu (AIMaS, TDTU) presents the topic: "Time-Dependent Electron Localization Function and Strong-Field Processes"

Abstract:

The time-dependent electron localization function (TDELF) allows the time-resolved observation of the breaking, changing, and formation of chemical bonds, and can thus provide a visual understanding of complex reactions involving electronic dynamics [1]. Using TDELF from the scientific open-source code OCTOPUS, which implemented the time-dependent density functional theory [2], we visualize the π-π* transition induced by a laser pulse of acetylene molecules.

Reference:

[1] T. Burnus, M. A. L. Marques, and E. K. U. Gross, Phys. Rev. A 71, 010501(R) (2005).

[2] M. A. L. Marques, A. Castro, G. F. Bertsch, and A. Rubio, Comput. Phys. Commun. 151, 60 (2003).