No abstract

In this study, a fiber laser at a wavelength of 1070 nm with different beam shapes (spot, dough-nut, and spot-wobble) was used to weld thin 316 L stainless steel foils. The welding speed was varied from 400 to 1000 mm/s in the absence of shielding gas. The weld geometry, microstructure, lap shear strength, and crystallographic grain structure of the micro-joints were analyzed and correlated with the beam shape and welding speed. The results indicate that the laser beam shape significantly affected the weld width and penetration depth, and the best welding speed was 500 mm/s. This study proved for the first time that a spot-wobble laser beam could achieve better mechanical properties and microstructural characteristics than a doughnut beam during the high-power laser welding of thin-foil stainless steel plates.

Abstract. Recent advances in direct conversion technology are of great significance in neuro-regenerative medicine. Conversion of somatic cells to a desired cell type is next generation reprogramming technology for clinical applications. The novel strategy of direct conversion of somatic cells into expandable multipotent neural cells (induced multipotent neural cells, iMNCs) and specific neurons (induced neurons, iNs) opens a new window of opportunities for cell therapy, disease specific modeling, and drug discovery for brain diseases.