Articles techniques et présentations

Germanium-tin (Ge₁₋ₓSnₓ) microdisks are emerging as a promising platform for CMOS-compatible group-IV light sources due to their tunable direct bandgap and compatibility with silicon photonics. Their optical and electronic properties are critically influenced by tin concentration, strain ... En savoir plus

The article deals with the magnetically-supported high-power full-penetration laser beam welding of aluminum. A stationary simulation was conducted accounting for the effects of natural convection, Marangoni convection and solid-liquid phase transition as well as an electromagnetic ... En savoir plus

A Laser-welded blank (LWB) consists of steels of different thicknesses and/or grades welded together to produce a single blank prior to the forming process. LWB are mostly used in the automotive field where the high productivity of the laser welding process is an advantage. Numerical ... En savoir plus

Synthetic jet actuators enhance flow control by generating pulsatile jets with zero net mass flux. There is a need to develop a computationally inexpensive model that can generate optimal geometric actuator designs of maximum jet performance. This work investigates the multi-physics ... En savoir plus

Surface plasmons in metal rectangular gratings can form bands and band gaps in their dispersion relations, analogous to those in photonic band-gap crystals and electronic bands in semiconductors. Introducing a dielectric coating atop the metal redshifts the plasmonic band gap, enabling a ... En savoir plus

Structural colors of photonic crystals demonstrate significant application value in optical sensing and anti-counterfeiting due to their high stability and environmental friendliness. However, current research still lacks systematic investigation into the structure-property relationship ... En savoir plus

Efficient mixing and pumping of liquids at the microscale is a technology that is still to be optimized. The combination of an AC electric field with a small temperature gradient leads to a strong electrothermal flow that can be used for multiple purposes. Combining simulations and ... En savoir plus

A 2D axisymmetric model was considered in order to evaluate the propagation paths of the ultrasonic waves generated inside an aluminum plate sample due to a rapid thermal expansion produced by laser pulse. Laser Doppler Vibrometer is used to experimentally validate the numerical results ... En savoir plus

During the welding of tantalum with a ND: YAG pulsed laser, a deep and narrow cavity, called the keyhole, is formed. At the end of the process, surface tension forces provoke the collapse of the keyhole. For important interface deformations, gas bubbles can be trapped into the melting ... En savoir plus

The Dynamic Transmission Electron Microscope (DTEM) at Lawrence Livermore National Laboratory is a unique instrument able to capture images of fast-evolving microstructure with exposure times of only 15 ns. This is more than six orders of magnitude faster than conventional in situ ... En savoir plus