634 research outputs found
Microwave conductivity of heavy fermions in UPd2Al3
Heavy-fermion compounds are characterized by electronic correlation effects
at low energies which can directly be accessed with optical spectroscopy. Here
we present detailed measurements of the frequency- and temperature-dependent
conductivity of the heavy-fermion compound UPd2Al3 using broadband microwave
spectroscopy in the frequency range 45 MHz to 40 GHz at temperatures down to
1.7 K. We observe the full Drude response with a relaxation time up to 50 ps,
proving that the mass enhancement of the heavy charge carriers goes hand in
hand with an enhancement of the relaxation time. We show that the relaxation
rate as a function of temperature scales with the dc resistivity. We do not
find any signs of a frequency-dependent relaxation rate within the addressed
frequency range.Comment: 14 pages, 4 figure
Influencing user behavior in office buildings through a co-creation process in order to achieve better energy efficiency and comfort
Providing users with relevant information raises their awareness on the influence of their behavior on the energy consumption and comfort in their workspace. A user-building interface was developed as part of this research through a co-creation process. It provides the occupants of monitored offices with information on their electricity and heating consumption, comfort indicators (temperature and air quality), light control and hints and tips on how to improve their behavior. This contribution describes the methodology used to improve the behavior of users in a pilot building and the results of a 32-week measurement campaign
Complex THz and DC inverse spin Hall effect in YIG/CuIr bilayers across a wide concentration range
We measure the inverse spin Hall effect of CuIr thin films on
yttrium iron garnet over a wide range of Ir concentrations (). Spin currents are triggered through the spin Seebeck effect,
either by a DC temperature gradient or by ultrafast optical heating of the
metal layer. The spin Hall current is detected by, respectively, electrical
contacts or measurement of the emitted THz radiation. With both approaches, we
reveal the same Ir concentration dependence that follows a novel complex,
non-monotonous behavior as compared to previous studies. For small Ir
concentrations a signal minimum is observed, while a pronounced maximum appears
near the equiatomic composition. We identify this behavior as originating from
the interplay of different spin Hall mechanisms as well as a
concentration-dependent variation of the integrated spin current density in
CuIr. The coinciding results obtained for DC and ultrafast
stimuli show that the studied material allows for efficient spin-to-charge
conversion even on ultrafast timescales, thus enabling a transfer of
established spintronic measurement schemes into the terahertz regime.Comment: 12 pages, 4 figure
TIFF-Korpus-Analyse
TIFF ist ein flexibles, anpassungsfähiges Dateiformat, das über die Jahre eine Vielzahl von Erweiterungen und Ergänzungen erfahren hat. Daneben bietet es die Möglichkeit, Metadaten in andern Standards (wie IPTC, EXIF oder ICC) einzubetten. Durch diese Flexibilität und Ausprägungen ist TIFF eigentlich als ein komplexes Dateiformat zu betrachten. TIFF ist zurzeit eine offene Spezifikation von Adobe, jedoch kein ISO-Standard. Diese Umstände, die aus archivischer Sicht nicht unbedenklich sind, haben die KOST 2014 bewogen, basierend auf der Baseline-TIFF-Spezifikation eine Empfehlung zu verfassen. Damit eine solche Empfehlung nicht nur auf theoretischen Überlegungen beruht, sondern sich auf eine fundierte Analyse echter archivischer Daten stützen kann, haben es die KOST und das DHLab Basel unternommen, mehrere Millionen Dateien aus drei Archiven systematisch zu untersuchen. Parallel dazu wurden an diesem Korpus auch etliche bekannte und in der Archivwelt verbreitete Analysetools getestet
Évaluation récursive des grammaires attribueés : deux implantations
Résumé disponbile dans les fichiers attaché
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