Articles techniques et présentations

Silicon solar cells still require cost reduction and improved efficiency to become more competitive. New architectures can provide a significant increase in efficiency, but today most of the approaches need additional processing steps. In this context, laser processing offers a unique ... En savoir plus

Nanoparticles are being extensively researched as a noninvasive method for selectively targeting and killing cancer cells. In this study, we model the thermal activation of gold nanospheres and nanorods in a fluidic environment to determine the thermal response of the surrounding medium. En savoir plus

The aim of the study is to predict the formation of porosities in the case of spot laser welding of tantalum. During the interaction, a deep and narrow cavity, called the keyhole, is generated. At the end of the interaction, surface tension provokes the collapse of the keyhole. Gas ... En savoir plus

This paper presents a numerical analysis of magnetic devices, dipole, quadrupole and undulator and a THz Free Electron Laser (FEL) electron-beam recovery system. Free Electron Laser are an important source of coherent radiation being used in the study of chemical properties of ... 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

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

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

设计了一种新型的介质激光波荡器。该设计的核心是一个周期性的介质结构，其两侧形成一个真空通道。通过引入两束特定波长的相向传播的平面激光波，在该真空通道内激励并产生一个相位同步的周期性电磁场。主要难点在于如何设计介质结构，使其在激光作用下，能够最大化提供偏转作用的横向电场Ey，同时必须将其他方向的场分量（如纵向场 Ez和加速场 Ex）对电子束的影响降至最低。 利用 COMSOL 求解了在两束相向传播的激光照射下，该周期性结构内部真空通道中的电磁场分布。通过仿真，验证即是否能成功在通道中心产生期望的周期性横向偏转电场，直观地展示电场沿不同方向的变化规律，从而评估波荡器的性能 ... En savoir plus

本文提出了一种新颖的介电激光加速器（DLA）结构，该结构利用三角梯度介电介质来增强逆切伦科夫效应（Inverse Cherenkov Effect, ICE），从而实现高梯度加速。逆切伦科夫效应是带电粒子从外部激光场中持续获取能量的过程，这在传统切伦科夫效应中是相反的，即粒子发射辐射。通过在介质中精确控制激光束的传播，可以产生一个与粒子速度同步的纵向电场分量，实现连续的净能量增益。为了验证这一概念并分析其性能，我们使用 COMSOL Multiphysics 进行了系统的仿真研究。仿真模型由一个位于自由空间域中的介电结构组成。我们应用散射边界条件（SBC ... 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