NachhaltigF: Europan Campus Rottal-Inn
O. Dmytriiev, U.A.S. Al-Jarah, Gangmei P., V. Kruglyak, R. Hicken, B. Mahato, B. Rana, M. Agrawal, A. Barman, M. Mátéfi-Tempfli, L. Piraux, Stefan Mátéfi-Tempfli
Static and dynamic magnetic properties of densely packed magnetic nanowire arrays
Physical Review B, vol. 87, no. 17
The static and dynamic magnetic properties of magnetic nanowire arrays with high packing density (>0.4) and wire diameter much greater than the exchange length have been studied by static and time-resolved magneto-optical Kerr effect measurements and micromagnetic simulations. The nanowires were formed by electrodeposition within a nanoporous template such that their symmetry axes lay normal to the plane of the substrate. A quantitative and systematic investigation has been made of the static and dynamic properties of the array, which lie between the limiting cases of a single wire and a continuous ferromagnetic thin film. In particular, the competition between anisotropies associated with the shape of the individual nanowires and that of the array as a whole has been studied. Measured and simulated hysteresis loops are largely anhysteretic with zero remanence, and the micromagnetic configuration is such that the net magnetization vanishes in directions orthogonal to the applied field. Simulations of the remanent state reveal antiferromagnetic alignment of the magnetization in adjacent nanowires and the formation of vortex flux closure structures at the ends of each nanowire. The excitation spectra obtained from experiment and micromagnetic simulations are in qualitative agreement for magnetic fields applied both parallel and perpendicular to the axes of the nanowires. For the field parallel to the nanowire axes, there is also good quantitative agreement between experiment and simulation. The resonant frequencies are initially found to decrease as the applied field is increased from remanence. This is the result of a change of mode profile within the plane of the array from nonuniform to uniform as the ground state evolves with increasing applied field. Quantitative differences between experimental and simulated spectra are observed when the field is applied perpendicular to the nanowire axes. The dependence of the magnetic excitation spectra upon the array packing density is explored, and dispersion curves for spin waves propagating within the array parallel to the nanowire axis are presented. Finally, a tunneling of end modes through the middle region of the nanowires was observed. The tunneling is more efficient for wires forming densely packed arrays, as a result of the extended penetration of the dynamic demagnetizing fields into the middle of the wires and due to the lowering of the tunneling barrier by the static demagnetizing field of the array.
NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: TC Teisnach Sensorik
M. Lukosius, C. Wenger, T. Blomberg, Günther Ruhl
Properties of stacked SrTiO3/Al2O3 metal–insulator–metal capacitors
Journal of Vacuum Science & Technology B, vol. 31, no. 1
The possibilities to grow thin films of SrTiO3 and Al2O3 by atomic layer deposition for stacked metal–insulator–metal capacitors have been investigated in this work. In order to tune the functional properties of the capacitors, different processing steps have been employed to realize different combinations of the dielectric stacks. Electrical properties, extracted after the postdeposition annealing and sputter deposition of the Au top electrodes, indicated that the metal–insulator–metal (MIM) structures with additional Al2O3 layer provided better leakage currents densities, compared to the ones with single SrTiO3 based MIM capacitors, but the dielectric constant values have also decreased if additional Al2O3 film was inserted. Attempts to optimize the properties of the MIM stacks have been done by manufacturing heterostructures of Al2O3/SrTiO3/Al2O3 as well as SrTiO3/Al2O3/SrTiO3. In the first case, Al2O3 prevented the crystallization of SrTiO3 in the multilayer dielectric structure and therefore reduced the total capacitance density of the particular MIM stack, whereas the SrTiO3/Al2O3/SrTiO3 stack was found to possess superior electrical properties. Leakage current density as low as ∼10−8 A/cm2 at 2 V and the dielectric constant value of 40 have been extracted.
NachhaltigF: Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
L. Ho, Markus Hainthaler, G. Newcombe
Using UV Spectroscopy and Molecular Weight Determinations to Investigate the Effect of Various Water Treatment Processes on NOM Removal: Australian Case Study
Journal of Environmental Engineering, vol. 139, no. 1
Natural organic material (NOM) has been the focus of many studies because of its ability to compromise water treatment processes. This case study utilized ultraviolet (UV) spectroscopy and molecular weight distributions to investigate the impact of six water treatment processes (alum coagulation, magnetic ion exchange (MIEX) resin treatment, chlorination, ozonation, powdered activated carbon (PAC) adsorption, and biological sand filtration) on the removal of NOM from an Australia water source, Myponga Reservoir. Each of these processes displayed different effects on the concentration and character of NOM. The removal of dissolved organic carbon (DOC) and UV absorbance at 254 nm (UV254) by MIEX and the biological sand filter was shown to follow first-order kinetics with rate constants ranging from 9.0×10−8 s−1 (biological sand filter) to 6.3×10−5 s−1 (MIEX treatment). UV spectroscopic investigations showed the potential to predict the formation of disinfection by-products from chlorination with strong correlations (R2 of 0.96) observed between the formation of trihalomethanes and the differential UV absorbance at 265 nm. Ozonation and biological sand filtration also appeared to target NOM absorbing at 265 nm. Molecular weight distribution analyses showed MIEX treatment to be the most effective single process in achieving high removals of a wide molecular weight range of NOM, consistent with the high removals of DOC and UV254 (up to 90% and 80% removal, respectively). The combination of alum and PAC, treatment options which exist at the majority of Australian water treatment plants, also proved effective for high NOM removal over a wide range of molecular weights, where alum effectively removed high molecular weight compounds, and PAC effectively removed low molecular weight compounds. This study has demonstrated that valuable information can be gained through simple manipulation of UV absorbance and molecular weight distribution data, which could be beneficial to water utilities in not only facilitating the selection of treatment processes when commissioning WTPs, but also optimizing existing treatment processes for effective NOM removal.
GesundF: Angewandte Gesundheitswissenschaften
Agnes Nocon, S. Jan, R. Rosner
Psychotherapeutic interventions from the western world in war-traumatized children - a metaanalysis
[Congress Abstract; 13th European Conference on Traumatic Stress: Trauma and its clinical pathways; PTSD and beyond; June 6-9, 2013, Bologna, Italy]
European Journal of Psychotraumatology, vol. 55, no. 4
F: Angewandte Gesundheitswissenschaften
Das Besuchen lernen. Regensburger Pilotprojekt für ehrenamtliche Besuchsdienste einer stationären Altenhilfeeinrichtung.
BAGSO-Nachrichten (Das Magazin der Bundesarbeitsgemeinschaft der Senioren-Organisationen), vol. 21, no. 2