TY - CHAP A1 - Staat, Manfred A1 - Ballmann, J. T1 - Fundamental aspects of numerical methods for the propagation of multi-dimensional nonlinear waves in solids T2 - Nonlinear hyperbolic equations : theory, computations methods, and applications ; proceedings of the 2nd International Conference on Nonlinear Hyperbolic Problems, Aachen N2 - The nonlinear scalar constitutive equations of gases lead to a change in sound speed from point to point as would be found in linear inhomogeneous (and time dependent) media. The nonlinear tensor constitutive equations of solids introduce the additional local effect of solution dependent anisotropy. The speed of a wave passing through a point changes with propagation direction and its rays are inclined to the front. It is an open question whether the widely used operator splitting techniques achieve a dimensional splitting with physically reasonable results for these multi-dimensional problems. May be this is the main reason why the theoretical and numerical investigations of multi-dimensional wave propagation in nonlinear solids are so far behind gas dynamics. We hope to promote the subject a little by a discussion of some fundamental aspects of the solution of the equations of nonlinear elastodynamics. We use methods of characteristics because they only integrate mathematically exact equations which have a direct physical interpretation. KW - Nichtlineare Welle KW - Nichtlineare Gleichung KW - Festkörper KW - Elastodynamik KW - Multi-dimensional wave propagation KW - nonlinear solids KW - nonlinear tensor constitutive equation Y1 - 1989 SP - 574 EP - 588 ER - TY - GEN A1 - Samm, Doris A1 - Meurer, Marcel T1 - Die elektrische Leitung und Supraleitung N2 - Die Lerneinheit stellt in anschaulicher Weise die verschiedenen Modelle der elektrischen Leitung dar und führt über diese zur Erklärung der Supraleitung. Effekte und Anwendungen der Supraleitung werden in Animationen und Bildern vorgeführt. Ein umfangreiches Glossar erläutert wichtige Begriffe. KW - Elektrische Leitung KW - Supraleitung KW - Elektronengas KW - Bändermodell KW - Festkörper KW - Elektrische Leitung KW - Supraleitung Y1 - 2003 ER -