63 research outputs found
A Comparative Study of the Valence Electronic Excitations of N_2 by Inelastic X-ray and Electron Scattering
Bound state, valence electronic excitation spectra of N_2 are probed by
nonresonant inelastic x-ray and electron scattering. Within the usual
theoretical treatments, dynamical structure factors derived from the two probes
should be identical. However, we find strong disagreements outside the dipole
scattering limit, even at high probe energies. This suggests an unexpectedly
important contribution from intra-molecular multiple scattering of the probe
electron from core electrons or the nucleus. These effects should grow
progressively stronger as the atomic number of the target species increases.Comment: Submitted to Physical Review Letters April 27, 2010. 12 pages
including 2 figure pages
Reexamining the Lyman-Birge-Hopfield band of N2
Motivated by fundamental molecular physics and by atmospheric and planetary sciences, the valence excitations of N2 gas have seen several decades of intensive study, especially by electron-energy-loss spectroscopy (EELS). It was consequently surprising when a comparison of nonresonant inelastic x-ray scattering (NIXS) and nonresonant EELS found strong evidence for violations of the first Born approximation for EELS when leaving the dipole scattering limit. Here we reassess the relative strengths of the constituent resonances of the lowest-energy excitations of N2, encompassed by the so-called Lyman-Birge-Hopfield (LBH) band, expanding on the prior, qualitative interpretation of the NIXS results for N2 by both quantifying the generalized oscillator strength of the lowest-energy excitations and also presenting a time-dependent density functional theory (TDDFT) calculation of the q dependence of the entire low-energy electronic excitation spectrum. At high q, we find that the LBH band has an unexpectedly large contribution from the octupolar w 1Δu resonance exactly in the regime where theory and EELS experiment for the presumed-dominant a 1Πg resonance have previously had substantial disagreement, and also where the EELS results must now be expected to show violations of the Born approximation. After correcting for this contamination, the a 1Πg generalized oscillator strength from the NIXS results is in good agreement with prior theory. The NIXS spectra, over their entire q range, also find satisfactory agreement with the TDDFT calculations for both bound and continuum excitations.This work was supported by the US Department of Energy, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Australian Research Council, the Research
Funds of the University of Helsinki, and the Academy of Finland (Contract No. 1127462, Centers of Excellence Program 2006-2011, and National Graduate School in Materials Physics). A.R. acknowledges support by MICINN (FIS2010-21282-C02-01),ACI-promociona (ACI2009-1036), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT-319-
07), and the European Community through e-I3 ETSF project (Contract No. 211956).Peer Reviewe
AnyNovel: detection of novel concepts in evolving data streams: An application for activity recognition
A data stream is a flow of unbounded data that arrives continuously at high speed. In a dynamic streaming environment, the data changes over the time while stream evolves. The evolving nature of data causes essentially the appearance of new concepts. This novel concept could be abnormal such as fraud, network intrusion, or a sudden fall. It could also be a new normal concept that the system has not seen/trained on before. In this paper we propose, develop, and evaluate a technique for concept evolution in
evolving data streams. The novel approach continuously monitors the movement of the streaming data to detect any emerging changes. The technique is capable of detecting the emergence of any novel concepts whether they are normal or abnormal. It also applies a continuous and active learning for assimilating the detected concepts in real time. We evaluate our approach on activity recognition domain as an application of evolving data streams. The study of the novel technique on benchmarked datasets showed its efficiency in detecting new concepts and continuous adaptation
with low computational cost
Revisiting the effect of history on learning performance: the problem of the demanding lord
Kinetic analysis for the determination of cure-dependent mechanical properties of adhesives
Zyklische Schubspannung-Gleitung-Beanspruchung von Klebverbindungen zur Schaedigungsidentifikation und Lebensdauerabschaetzung Schlussbericht
SIGLEAvailable from TIB Hannover: F00B1035 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekArbeitsgemeinschaft Industrieller Forschungsvereinigungen 'Otto von Guericke' e.V. (AIF), Koeln (Germany); Bundesministerium fuer Wirtschaft, Bonn (Germany)DEGerman
US-Detektion von Klebverbindungsfehlern und deren Auswirkungen auf die Beanspruchbarkeit der Verbindung bei statischer und schwigender Beanspruchung
Das von der AiF geförderte Forschungsprojekt hat zum Ziel, ein robustes US-Prüfverfahren zur Qualitäts- und Zuverlässigkeitsbeurteilung an industriell ausgeführten Klebverbindungen zu entwickeln und die Bewertung von detektierten Fehlern auf das mechanische Verhalten zu beurteilen. Dazu wurden fehlerfreie und fehlerbehaftete Klebverbindungen zerstörungsfrei vor und während der mechanischen Beanspruchung geprüft und die Auswirkungen der Fehler bei quasistatisch zügiger und schwingender Beanspruchung zerstörend untersucht
Finite Deformation Elasto-Plasticity for Simulation of Strength Difference in Adhesive Materials with an Algorithm in Principal Directions
Influence of processing methods on starch properties
9 pags., 6 figs.Native potato starch was prepared using different processing methods. The samples were characterized by wide-angle X-ray scattering (WAXS), optical microscopy, differential scanning calorimetry (DSC), and microhardness. Compression molding of the starch granules led to sintered relatively brittle materials. Here, the amylopectin crystals of the native powder remained grossly preserved. Preparation of dry films from aqueous gels resulted in disintegration of the structure of the native starch granules and in the formation of a new semicrystalline structure comprised of crystallized amylose molecules. Injection molding of native starch was found to be a processing method that gives rise to amorphous materials with superior mechanical properties.We acknowledge DGICYT (grant PB94-0049), Spain, for the generous support of
this investigation
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