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.

Thermal conductivity of a single fracture

Abstract: The macroscopic conductivity of fractures is determined for Gaussian and self-affine fractures by solving the three-dimensional Laplace equation. Results are discussed and compared with various analytical or two-dimensional approximations. They are shown to be in good agreement with some existing experimental data.

Renormalization of QED in an external field

Abstract: The Schwinger equations of QED are rewritten in three different ways as integral equations involving functional derivatives, which are called weak field, strong field, and SCF quantum electrodynamics. The perturbative solutions of these equations are given in terms of appropriate Feynman diagrams. The Green function that is used as an electron propagator in each case is discussed in detail. The general renormalization rules for each of the three equations are provided both in a non perturbative way (Dyson relations) and for Feynman diagrams.

Nouveau pôle paléomagnétique Stephanien inférieur pour le craton saharien (formation de Merkala, bassin de Tindouf, Algérie)

Abstract: A palaeomagnetic study carried out in the Lower Stephanian Merkala formation (Tindouf basin) pointed out two juxtaposed neighbouring components of the magnetization. The oldest one allowed a new Stephanian pole located at 32.4°S and 56.6°E (K= 399, A9.5 = 2.3°) to be obtained. The other one results from the superimposition of this old component on a Permian remagnetization. The new Stephanian pole, associated with the previous data from the Saharan craton, allows the Stephano-Autunian segment of the African apparent polar wander path to be specified.

Palaeomagnetic studies in the Permian Basin of Largentiere and implications for the Late Variscan rotations in the French Massif Central

Abstract: SUMMARY Detailed geological observations and palaeomagnetic analyses were carried out in the Largentiere Stephano-Autunian basin and on the Stephanian deposits of the Ales coalfield, both located at the southeastern margin of the French Massif Central. Because of unfavourable rock types, the Ales Stephanian deposits did not yield any results. The palaeomagnetic pole (164.9°E, 45.4°N, K=89, A 95 =4.1°) deduced from a study of the Autunian sediments of the Largentiere Basin agrees very well with the reference pole for stable Europe. The Lodeve-Largentiere area, that is the southeastern border of the Massif Central, has been stable since Early Permian time with respect to stable Europe, whereas the western part (the Saint-AVrique Rodez Basin and, probably, the Brive Basin) has been rotated counterclockwise.