Problems and procedures for preservation and dissemination of computer-readable data

Der Autor gibt einen historischen Überblick über die Entwicklung der Datenbearbeitung, Aufbewahrung und Verbreitung der National Archives and Records Services in den USA. Dabei wird die Einführung der computerlesbaren Datenverarbeitung in den Vordergrund gestellt. Daran anschließend werden Probleme, Zielstellungen und konkrete Verfahrensweisen bei der Sammlung und Verarbeitung computerlesbarer Daten angesprochen. (BG

Phase matching of noncollinear sum and difference frequency high harmonic generation above and below the critical ionization level

We investigate the macroscopic physics of noncollinear high harmonic generation (HHG) at high pressures. We make the first experimental demonstration of phase matching of noncollinear high-order-difference-frequency generation at ionization fractions above the critical ionization level, which normally sets an upper limit on the achievable cutoff photon energies. Additionally, we show that noncollinear high-order-sum-frequency generation requires much higher pressures for phase matching than single-beam HHG does, which mitigates the short interaction region in this geometry. We also dramatically increase the experimentally realized cutoff energy of noncollinear circularly polarized HHG, reaching photon energies of 90 eV. Finally, we achieve complete angular separation of high harmonic orders without the use of a spectrometer.Department of Energy BES Award DE-FG02-99ER14982. MURI grant from the Air Force Office of Scientific Research under Award Number FA9550-16-1-0121. National Science Foundation Graduate Research Fellowship (DGE-1144083). Junta de Castilla y León (Project SA046U16) and Spanish MINECO (FIS2013-44174-P, FIS2016-75652-P)

The SFA Business Review Vol. 2 No. 1

https://scholarworks.sfasu.edu/busreview/1002/thumbnail.jp