IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

Modelling the spectral induced polarization response of water-saturated sands in the intermediate frequency range (102–105 Hz) using mechanistic and empirical approaches

Abstract: HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Modelling the spectral induced polarization response of water-saturated sands in the intermediate frequency range (102–105 Hz) using mechanistic and empirical approaches Thomas Kremer, Myriam Schmutz, Philippe Leroy, Pierre Agrinier, Alexis Maineult

Active tectonics of the onshore Hengchun Fault using UAS DSM combined with ALOS PS-InSAR time series (Southern Taiwan)

Abstract: . Characterizing active faults and quantifying their activity are major concerns in Taiwan, especially following the major Chichi earthquake on 21 September 1999. Among the targets that still remain poorly understood in terms of active tectonics are the Hengchun and Kenting faults (Southern Taiwan). From a geodynamic point of view, the faults affect the outcropping top of the Manila accretionary prism of the Manila subduction zone that runs from Luzon (northern Philippines) to Taiwan. In order to better locate and quantify the location and quantify the activity of the Hengchun Fault, we start from existing geological maps, which we update thanks to the use of two products derived from unmanned aircraft system acquisitions: (1) a very high precision (< 50 cm) and resolution (< 10 cm) digital surface model (DSM) and (2) a georeferenced aerial photograph mosaic of the studied area. Moreover, the superimposition of the resulting structural sketch map with new Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) results obtained from PALSAR ALOS images, validated by Global Positioning System (GPS) and leveling data, allows the characterization and quantification of the surface displacements during the monitoring period (2007–2011). We confirm herein the geometry, characterization and quantification of the active Hengchun Fault deformation, which acts as an active left-lateral transpressive fault. As the Hengchun ridge was the location of one of the last major earthquakes in Taiwan (26 December 2006, depth: 44 km, M L= 7.0), Hengchun Peninsula active tectonics must be better constrained in order if possible to prevent major destructions in the near future.

Relaxation study of pre-densified silica glasses under 2.5 MeV electron irradiation.

Abstract: We examined the “relaxation properties” of pre-densified synthetic fused silica glass under 2.5 MeV electron irradiation. The densification of the glass was either obtained by hot compression (5 GPa-350 °C and 5 GPa-1000 °C) or via a thermal treatment increasing its fictive temperature (Tf = 1050, 1250 and 1400 °C). Under irradiation, the pre-densified silica glasses exhibit a relaxation of their macroscopic density with increasing integrated dose. Density was reduced for hot compressed silica and increased for Tf samples with different relaxation rates but it is remarkable that all sample densities follow a trend towards the same equilibrium value around 2.26 for a dose larger than 10 GGy despite a different final topology. After irradiation of hot compressed silica, the Raman spectra display a significant increment of 4 and almost 3-membered rings whereas they exhibit a glass density reduction; demonstrating that a D2 band increase cannot be considered as an absolute marker of the glass compaction. The correlation between density and D2 intensity remains valid until silica density remains lower than 2.26. In contrast, the FWHM of the main band peaking at 440 cm−1 appears to remain correlated to the silica glass density for all investigated samples.

High-pressure behaviour of germanate olivines studied by X-ray diffraction and X-ray absorption spectroscopy

Abstract: Germanate olivines Mg2GeO4, Ca2GeO4 and CaMgGeO4 have been studied by high-pressure X-ray Diffraction and high-pressure X-ray Absorption Spectroscopy. The three compounds were compressed, in the 0–30 GPa pressure range, at room temperature in a diamond-anvil cell, silicon oil being used as the pressure transmitting medium. Values of K0 are 166 ± 15, 117 ± 15 and 152 ± 14 GPa for Mg2GeO4, Ca2GeO4 and CaMgGeO4 respectively. These olivines all exhibit compression anisotropy, the a axis being the least compressible. Crystal to crystal phase transitions have been observed in Mg2GeO4 and Ca2GeO4 above 12 GPa and 6 Gpa respectively. The nature of these structural changes remains unclear yet. The onset of amorphization has been observed in Mg2GeO4 and Ca2GeO4 at pressures above about 22 and 11 GPa respectively. These phase transitions and amorphization processes do not involve any detectable increase in the coordination number of germanium atoms. At higher pressure (P >23 GPa), we report the onset of a transition from a phase with fourfold coordinated germanium to a phase with higher germanium coordination number in CaMgGeO4.