These findings provide new therapeutic perspectives for the treatment of muscle injuries, sarcopenia, and cachectic disease, but also imply that such a substance could be abused for doping purposes.
In this paper we study the influence of the processing wavelength on process efficiency and quality at picosecond microdrilling in steel. Possible optical setups for utilizing the second harmonic will be presented, and the influence of wavelength on the drilling rate will be discussed. The potential of helical drilling with the second harmonic in 1 mm thick CrNi-steel will be investigated with regard to process efficiency and hole quality. An analysis will be given of the role of particle-ignited atmospheric plasma and the relation between isophote contour and hole morphology. Our study reveals that a substantial enhancement of both precision and productivity can be achieved by using frequency-doubled instead of infrared radiation. It is shown that plasma ablation and melt production can be minimized by drilling with the second harmonic.
The cleaving process has the potential to replace the dicing of thin wafers. Its inherent advantages are no mechanical forces to the substrate, no material losses, and high edge quality. In order to determine the fundamental mechanisms leading to a reliable cleaving process the complex interaction of wavelength and temperature dependent absorption, heat transfer, material elongation and finally crack formation is theoretically described and experimentally verified. A successful process observed if sufficient thermal stress can be generated to induce a crack and if no surface deformation occurs due to overheating. Most relevant parameters determining the process window are irradiated power, cutting speed, and focus spot size. The results of these parameter variations are presented. Accuracy and reproducibility is demonstrated by cleaving stripes of different widths fulfilling the requirements of the electronic packaging industry. In the third section the influence of the crystalline orientation is investigated. As a result mono-crystalline silicon exhibits an anisotropic behaviour when changing the cutting direction whereas for polycrystalline substrates a permanent change of the crystal structure is found at the grain boundary. Finally, the obtainable edge quality is presented briefly, which leads to higher sample strengths compared to conventional laser and mechanical processes.
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