The formation of superabundant vacancies (SAVs; vacancy-hydrogen clusters) was studied in Nb-H alloys by means of resistivity measurements as a function of temperature, pressure and H concentration. The formation energy of a vac-H cluster (0.3 ± 0.1 eV), which is 1/10 of the formation energy of a vacancy in Nb, is explained tentatively as being the consequence of six H atoms trapped by a vacancy with the average binding energy of 0.46 eV/H atom. The SAVs were introduced from the external surface, and transported into the interior by direct bulk diffusion and/or by fast diffusion along dislocations. The activation volumes for the formation and migration of vac-H clusters were determined to be 3.7 and 5.3 Å 3 , respectively.

Adaptive all-order dispersion compensation of ultrafast laser pulses using dynamic spectral holography

We report an ultrafast web inspector that operates at a 1000 times higher scan rate than conventional methods. This system is based on a hybrid dispersion laser scanner that performs line scans at nearly 100 MHz. Specifically, we demonstrate web inspection with detectable resolution of 48.6 μm/pixel (scan direction) × 23 μm (web flow direction) within a width of view of 6 mm at a record high scan rate of 90.9 MHz. We demonstrate the identification and evaluation of particles on silicon wafers. This method holds great promise for speeding up quality control and hence reducing manufacturing costs.

Picosecond time-resolved x-ray diffraction is used to probe single-crystal silicon under pulsed-laser irradiation (300 ps pulse at 1.4 J/cm2) at an interval of 60 ps. The observed rocking curves show shock compression of the silicon lattice by the laser irradiation. Uniaxial strain profiles perpendicular to the Si(111) plane are estimated using dynamical x-ray diffraction theory. The temporal and spatial evolution of the profiles indicates a propagating shock wave with the velocity of 9.4 km/s inside the silicon crystal. The observed maximum compression is 1.05%, which corresponds to a pressure of 2.18 GPa.