Laser Ablation Mechanism Deduced from Structural Changes of Metal Target

Study of laser ablation using nano-second laser pulses

 In this paper, the laser ablation process based on the irradiation of nanosecond pulsed lasers on a copper target surface in the presence of Helium gas is studied. The dynamical behaviors of the generated plasma in the helium gas and evaporated copper at the atmospheric pressure are examined using a laser pulse, laser wavelength of and intensity of 7×1010W/cm2. A one-dimensional thermal model ...

Laser-ablation Icp-ms Analyses of Meteoritic Metal Grains

Introduction: Lunar impact-melt breccias contain metal grains from the meteorites that formed the breccias. Because the breccias contain clastic material that may derive from older breccias, metal grains from earlier impacts may be present, too. The large subset of moderately mafic (8– 12% FeO), KREEP-rich (“LKFM”) melt breccias is particularly important because (1) these are the melt breccias ...

Hydrodynamic simulations of metal ablation by femtosecond laser irradiation

Surface instability of multipulse laser ablation on a metallic target

Large scale wavelike patterns are observed on an aluminum surface after it is ablated by a series of KrF laser pulses ~248 nm, 40 ns, 5 J/cm!. These surface structures have a wavelength on the order of 30 mm, much longer than the laser wavelength. We postulate that these wave patterns are caused by the Kelvin–Helmholtz instability at the interface between the molten aluminum and the plasma plum...

Putative mechanism of natural transformation as deduced from genome data.

Genetic transformation is widely utilized in molecular biology as a tool for gene cloning in Escherichia coli and for gene mapping in Bacillus subtilis. Several strains of eubacteria can naturally take up exogenous DNA and integrate the DNA into their own genomes. Molecular details of natural transformation, however, remained to be elucidated. The complete genome of a cyanobacterium, Synechocys...