Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf
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43564 Publications
Structure and energetics of nanoclusters in bcc-Fe containing vacancies, Cu, and Ni.
Al-Motasem, A. T.; Posselt, M.; Bergner, F.; Birkenheuer, U.
Abstract
Reactor pressure vessel (RPV) steels consist of polycrystalline bcc-Fe containing Cu, Ni and other foreign atoms. The continuous irradiation by fast neutrons leads to supersaturation of vacancies and self-interstitials and enhances the diffusion of Cu and Ni which occurs via the vacancy mechanism. These processes favor the formation of nanoclusters consisting of vacancies, Cu and Ni. The interaction of dislocations with these precipitates is considered to be the main cause of hardening and embrittlement of the RPV steels. In order to model the evolution of the precipitates under irradiation by rate theory or object kinetic Monte Carlo simulations, the energetics and thermodynamics of the clusters must be known. These data are hardly obtainable by experiments, however, they can be provided by atomic-level computer simulations. In the present work a combination of on-lattice simulated annealing based on Metropolis Monte Carlo simulations and off-lattice relaxation by Molecular Dynamics calculations is employed to determine structure and energetics of the nanoclusters. In particular the influence of Ni on the formation of clusters containing Cu and/or vacancies is investigated. The atomistic simulations show that ternary clusters exhibit a shell structure with a core consisting of vacancies followed by a shell of Cu and an outer shell of Ni. Binary vacancy-Cu and Ni-Cu clusters show a similar shell structure, whereas the atomic configuration of vacancy-Ni agglomerates is completely different. For further application in rate theory and object kinetic Monte Carlo simulations compact and physically-based fit formulae are derived from the atomistic data for the total and the monomer binding energy.
Keywords: Fe-Cu-Ni; defects; Metropolis Monte Carlo and Molecular Dynamics
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Lecture (Conference)
E-MRS 2011 SPRING MEETING IUMRS ICAM 2011 & E-MRS/MRS BILATERAL CONFERENCE on ENERGY, 09.-13.05.2011, Nice, France
Permalink: https://www.hzdr.de/publications/Publ-15662
Concurrent annealing and irradiation of germanium to control dopant diffusion and activation
Bracht, H.; Schneider, S.; Klug, J. N.; Posselt, M.; Schmidt, B.
Abstract
Germanium (Ge) as material for microelectronic applications has received renewed attention over the past decade. This is due to the advantageous electron and hole mobilities that are higher than those of silicon (Si). However, several obstacles still exist that limit the fabrication of Ge-based nanoelectronic devices. One aspect concerns the limited activation of donor atoms. The deactivation is mainly attributed to the formation of dopant-vacancy clusters whose existence is supported by density functional theory calculations. In this work we discuss experiments on the diffusion of implanted phosphorous (P) and arsenic (As) in Ge under proton irradiation. Continuum theoretical simulations of dopant profiles measured by means of secondary ion mass spectrometry reveal that diffusion under irradiation is much less affected by inactive donor-vacancy clusters than diffusion under annealing only. The suppression of donor-vacancy clusters is caused by interstitials in supersaturation and vacancy concentrations close to thermal equilibrium. Applying the approach of concurrent annealing and irradiation high active doping levels in Ge can be realized even at low processing temperatures.
Keywords: germanium; dopants; defects; diffusion; activation
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15661) publication
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Poster
E-MRS ICAM IUMRS 2011 Spring Meeting, 09.-13.05.2011, Nice, France
Permalink: https://www.hzdr.de/publications/Publ-15661
Combining contactless inductive flow tomography and mutual inductance tomography for the flow determination in a model of continuous casting
Wondrak, T.; Stefani, F.; Gerbeth, G.; Timmel, K.; Peyton, A. J.; Yin, W.; Terzija, N.
Abstract
In the continuous casting process the flow structure in the mold plays an important role for the quality of the produced steel. Open issues of this technoloqy concern the influence of a two phase flow in the submerged entry nozzle and the influence of electromagnetic stirrers.
One possible method to determine the flow structure in the mold is the contactless inductive flow tomography (CIFT) which is able to reconstruct the three-dimensional velocity field in electrically conducting melts from externally measured induced magnetic fields. Since for thin slab casting the velocity can be assumed to be mainly two-dimensional it is sufficient to apply only one external magnetic field and to measure the induced fields at the narrow faces of the mold. The actual time resolution is about 1 Hz.
We will present the results [1,2] of an experiment with a two phase flow regime and the effects of an electromagnetic stirrer around the submerged entry nozzle on the flow field in the mold.
[1] Th. Wondrak et al. (2010), Meas. Sci. Techn. 21, 045402
[2] N. Terzija et al. (2011), Meas. Sci. Techn. 22, 015501
Keywords: contactless inductive flow tomography; mutual inductance tomography; flow visualization; continuous casting
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Contribution to proceedings
8th International PAMIR conference on fundamental and applied MHD, 05.-9.9.2011, Borgo, France, 569-573 -
Lecture (Conference)
8th International PAMIR conference on fundamental and applied MHD, 05.-9.9.2011, Borgo, France
Permalink: https://www.hzdr.de/publications/Publ-15660
Contactless inductive flow tomography at a liquid metal model of the steel casting process
Wondrak, T.; Stefani, F.; Gundrum, T.; Timmel, K.; Gerbeth, G.
Abstract
The contactless inductive flow tomography (CIFT) allows the reconstruction of the full three- dimensional mean velocity field in electrically conducting melts from externally measured induced magnetic fields. One of its possible applications is the velocity reconstruction in the continuous casting process. We present CIFT measurements performed at the small-scale liquid metal facility Mini-LIMMCAST which uses the room-temperature liquid alloy GaInSn for modelling of the thin-slab casting process. It will be shown that the flow structure, in general, and the jet position and intensity, in particular, can be reliably determined from magnetic field data using only a modest number (in the order of 5) of sensors. Even the very asymmetric flow in case of artificially closing one of the two nozzle outlets is reproduced by CIFT. The CIFT measurements are partly validated by comparison with ultrasonic velocity measurements.
Keywords: contactless inductive flow tomography; flow visualization; continuous casting
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Lecture (Conference)
4th International Conference on Modelling and Simulation of Metallurgical Processes in Steelmaking (SteelSim), 27.06.-1.7.2011, Düsseldorf, Deutschland -
Contribution to proceedings
4th International Conference on Modelling and Simulation of Metallurgical Processes in Steelmaking (SteelSim), 27.06.-1.7.2011, Düsseldorf, Deutschland
Proceedings of the 4th International Conference on Modelling and Simulation of Metallurgical Processes in Steelmaking (SteelSim)
Permalink: https://www.hzdr.de/publications/Publ-15659
Combination of the contactless inductive flow tomography and the mutual inductance tomography for the flow visualization in a model of continuous casting
Wondrak, T.; Gerbeth, G.; Stefani, F.; Timmel, K.; Peyton, A. J.; Terzija, N.; Yin, W.
Abstract
Continuous casting is a widely used technique in the steel producing industry today. The flow structure in the mold has a great impact on the quality of the produced steel. Open issues of this technology concern the influence of a two phase flow in the submerged entry nozzle and the influence of electromagnetic stirrers.
One possible technique to visualize the flow structure in electrically conducting melts is the contactless inductive flow tomography (CIFT) which is able to reconstruct the three-dimensional velocity field by measuring induced magnetic fields outside the melt. Since for thin slab casting the velocity in the mold can be assumed to be mainly two-dimensional it is sufficient to apply only one external magnetic field and to measure the induced fields at the narrow faces of the mold. The actual time resolution is about 1 Hz.
We will present the results [1,2] of an experiment with a two phase flow regime combining CIFT and the mutual inductance tomography to measure the flow structure in the mold and the gas/liquid distribution in the submerged entry nozzle. Additionally we show the effects of an electromagnetic stirrer around the submerged entry nozzle on the flow field in the mold.
[1] Th. Wondrak et al. (2010), Meas. Sci. Techn. 21, 045402
[2] N. Terzija et al. (2011), Meas. Sci. Techn. 22, 015501
Keywords: contactless inductive flow tomography; mutual inductance tomography; flow visualization; continuous casting
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Lecture (Conference)
Jahrestagung der Gesellschaft für angewandte Mathematik und Mechanik (GAMM 2011), 18.-21.04.2011, Graz, Österreich
Permalink: https://www.hzdr.de/publications/Publ-15658
A TRLFS study of curium(III) naphthalene and hydroxyquinoline complexes in aqueous solution
Moll, H.; Bernhard, G.
Abstract
The unknown complex formation of Cm(III) with two naphthalene ligands, 2,3dihydroxynaphthalene (23NAP) and 2naphthalene (2NAP) as well as 6hydroxyquinoline (6HQ) was studied by time-resolved laser-induced fluorescence spectroscopy (TRLFS). Aromatic molecules with hydroxyl groups have the potential to enhance the solubility and mobility of metals by forming complexes. We explored both the luminescence (lifetimes and individual emission spectra) and the excitation properties (excitation spectra) of the formed Cm(III) species. The experiments were performed at a fixed total Cm(III) concentration of 0.3 µM by varying the ligand concentrations (0.03-3.0 mM) and the pH (1.9-12.4) at an ionic strength of 0.1 M (NaClO4). The spectroscopic speciation indicates the formation of CmpLqHr species. In more detail, Cm(III) forms 1:1 and 1:2 complexes with 23NAP, a 1:2 complex with 2NAP and a 1:1 complex with 6HQ. Independent from the ligand and at pH values above 9.5 strong indications were found for ternary complexes with OH- with a 1:2:-1 stoichiometry. The Cm(III)-23NAP complexes exhibited the largest red shift of the Cm3+ emission maximum at 593.7 nm to: 598.3 nm for Cm(23NAP)H2+, 604.4 nm for Cm(23NAP)+, 608.4 nm for Cm(23NAP)2-, and 616 nm for Cm(23NAP)2OH2-. Based on the factor analysis of the emission data the stability constants were calculated to be: (a) for 23NAP log ß111 = 20.2 ± 0.8, log ß110 = 12.7 ± 0.4, log ß120 = 20.5 ± 0.4, and log ß12-1 = 9.7 ± 0.4; (b) for 2NAP log ß120 = 19.4 ± 0.2, and log ß12-1 = 10.3 ± 0.1; and (c) for 6HQ log ß110 = 8.8 ± 0.3, and log ß12-1 = 5.1 ± 0.9 at an ionic strength of 0.1 M (NaClO4). The stability constants were compared to those of natural pyoverdins.
Keywords: Cm(III); Complexation; TRLFS; 2,3-hydroxynaphthalene; 2-naphthalene; 6-hydroxyquinoline
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Polyhedron 31(2012), 759-766
DOI: 10.1016/j.poly.2011.11.007
Cited 7 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15657
CFD for two-phase flows - recent developments, status and further requirements -
Lucas, D.; Laurien, E.
Abstract
The use of Computational Fluid Dynamics (CFD) Codes for two-phase flow problems in Nuclear Safety Research is discussed. Examples for recent developments are the qualification of MUSIG model for dispersed flows and the modelling of free surfaces. Up to now the predictive capabilities of CFD codes for two-phase flows are limited to special cases. Nevertheless a valuable contribution to understand such complex flows is obtained. The aim of the future research is to develop CFD codes towards a quantitative method to obtain reliable predictions for broad range of applications.
Keywords: CFD; two-phase flow
Involved research facilities
- TOPFLOW Facility
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Invited lecture (Conferences)
Annual Meeting on Nuclear Technology, Jahrestagung Kerntechnik, 17.-19.05.2011, Berlin, Germany
Permalink: https://www.hzdr.de/publications/Publ-15656
Characterization of plunging liquid jets: A combined experimental and numerical investigation
Qu, X. L.; Khezzar, L.; Danciu, D.; Labois, M.; Lakehal, D.
Abstract
This paper presents a combined experimental and numerical study of the flow characteristics of round vertical liquid jets plunging into a cylindrical liquid bath. The main objective of the experimental work consists in determining the plunging jet flow patterns, entrained air bubble sizes and the influence of the jet velocity and variations of jet falling lengths on the jet penetration depth. The instability of the jet influenced by the jet velocity and falling length is also probed. On the numerical side, two different approaches were used, namely the mixture model approach and interface-tracking approach using the level-set technique with the standard two-equation turbulence model. The numerical results are contrasted with the experimental data. Good agreements were found between experiments and the two modelling approaches on the jet penetration depth and entraining flow characteristics, with interface tracking rendering better predictions. However, visible differences are observed as to the jet instability, free surface deformation and subsequent air bubble entrainment, where interface tracking is seen to be more accurate. The CFD results support the notion that the jet with the higher flow rate thus more susceptible to surface instabilities, entrains more bubbles, reflecting in turn a smaller penetration depth as a result of momentum diffusion due to bubble concentration and generated fluctuations. The liquid average velocity field and air concentration under tank water surface were compared to existing semianalytical correlations. Noticeable differences were revealed as to the maximum velocity at the jet centreline and associated bubble concentration. The mixture model predicts a higher velocity than the level-set and the theory at the early stage of jet penetration, due to a higher concentration of air that cannot rise to the surface and remain trapped around the jet head. The location of the maximum air content and the peak value of air holdup are also predicted differently.
Keywords: Plunging jet; Penetration; Air entrainment; Mixture model; Level-set; CFD
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International Journal of Multiphase Flow 37(2011)7, 722-731
DOI: 10.1016/j.ijmultiphaseflow.2011.02.006
Cited 59 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15655
Comparison of two turbulence models in simulating an axisymmetric water jet evolving into a water tank
Zidouni Kendil, F.; Danciu, D.-V.; Mataoui, A.; Schmidtke, M.; Lucas, D.; Bousbia Salah, A.
Abstract
Experiments and computational fluid dynamics (CFD) simulations have been carried out to predict a turbulent water jet plunging into a tank filled with the same liquid. A zero distance of the free falling water jet to the free surface of the tank is considered in order to avoid air bubble entrainment which may be caused by surface instabilities.
For both impinging region and recirculation zone, measurements are made using Particle Image Velocimetry (PIV). Instantaneous and time-averaged velocity fields are obtained over the cross-section of the tank. Numerical data is obtained on the basis of both k-ε and SSG (Speziale, Sarkar and Gatski) of Reynolds Stresses Turbulent Model (RSM) in three dimensional frame and compared to experimental results via the axial velocity and turbulent kinetic energy.
It was found that, for axial distances lower than 5 cm from the jet impact point, the axial velocity matches well the measurements, using both models. A progressive difference is noticed near the jet for higher axial distances from the jet impact point. These discrepancies are more important in the case of RSM than in the case of k-ε model. Nevertheless, it was observed that the turbulent kinetic energy agrees very well with the measurements when applying the SSG-RSM model for the lower part of the tank, whereas it is underestimated in the upper region, especially in the region near the jet exit. Inversely, the k-ε model shows better results in the upper part of the water tank and underestimates results for the lower part of the water tank. From the overall results, it can be concluded that the k-ε model describes well the average axial velocity, whereas the turbulent kinetic energy is better represented by the SSG-RSM model. The flow pattern obtained using both turbulent models and the corresponding comments of the results are detailed in the paper.
Keywords: Impinging jet; Standard k-ε Turbulent Model; Reynolds Stresses Turbulent Model
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Contribution to proceedings
European Turbulence Conference (ETC 13), 12.-15.09.2011, Warsaw, Poland
Comparison of two turbulence models in simulating an axisymmetric water jet evolving into a water tank -
Journal of Physics: Conference Series 318(2011), 042035
DOI: 10.1088/1742-6596/318/4/042035
Cited 2 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15654
S-Layer-basierte Materialien zur Detektion und Entfernung von Schad- und Wertstoffen
Raff, J.
Abstract
Vorstellung aktueller Arbeiten zur Entwcklung S-Layer-basierter Materialien
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 15653) publication
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Lecture (others)
Biomatum-Seminar, 17.05.2011, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15653
Image based in-vivo dosimetry: from PET to in-beam SPECT
Fiedler, F.
Keywords: in-beam PET; in-beam SPECT; PET; dose monitoring; in vivo dosimetry; ion therapy; proton therapy
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Invited lecture (Conferences)
2nd Workshop on Hadron Beam Therapy of Cancer, 20.-27.05.2011, Erice, Italy
Permalink: https://www.hzdr.de/publications/Publ-15652
A 200 cm × 50 cm MRPC-based prototype for the NeuLAND detector at R3B
Bemmerer, D.; Cowan, T.; Elekes, Z.; Kempe, M.; Röder, M.; Sobiella, M.; Stach, D.; Wagner, A.; Yakorev, D.; Zuber, K.
Abstract
A detector for high-resolution momentum measurements of neutrons in the energy range 0.2-1.0 GeV is being developed for the R3 B experiment at FAIR. Two solutions are currently being studied: A pure scintillator concept and an approach based on a sequence of converter material (iron) to produce secondary charged particles, and Multigap Resistive Plate Chambers (MRPC’s) to detect these particles. Here, work on the latter solution is reported.
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 15651) publication
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Contribution to external collection
Katrin Große: GSI Annual Report 2010; GSI-Report 2011-1, Darmstadt: GSI Helmholtzzentrum für Schwerionenforschung, 2011, 182
Permalink: https://www.hzdr.de/publications/Publ-15651
NeuLAND - Concepts for the Detection of Fast Neutrons
Aumann, T.; Basu, P.; Bemmerer, D.; Bertini, D.; Blanco, A.; Boretzky, K.; Caesar, C.; Chakraborty, S.; Chatterjee, S.; Cherciu, M.; Datta Pramanik, U.; Elekes, Z.; Fonte, P.; Galaviz, D.; Gonzalez Diaz, D.; Haiduc, M.; Hehner, J.; Heil, M.; Ignatov, A.; Kempe, M.; Leifels, Y.; Machado, J.; Maroussov, V.; Panja, J.; Potlog, M.; Rahaman, A.; Reifarth, R.; R. ̈Oder, M.; Rossi, D.; Simon, H.; Sobiella, M.; Stach, D.; Stan, E.; Teubig, P.; Wagner, A.; Yakorev, D.; Zilges, A.; Zuber, K.
Abstract
The acronym NeuLAND (new Large Area Neutron De-tector) stands for the high-efficiency time-of-flight spectrometer for high-energy neutrons (200 to 1000 MeV) within the R3B experiment being designed for FAIR. A spatial resolution of approximately sigma~1 cm and a time resolution of approximately sigma~100 ps are envisaged together with an efficiency of more than 90 % for one-neutron events, as well as a high multi-neutron recognition capability.
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 15650) publication
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Contribution to external collection
Katrin Große: GSI Annual Report 2010; GSI-Report 2011-1, Darmstadt: GSI Helmholtzzentrum für Schwerionenforschung, 2011, 180
Permalink: https://www.hzdr.de/publications/Publ-15650
Direct reactions of light exotic beams measured in complete kinematics at R3B
Adachi, T.; Aksyutina, Y.; Alcantara, J.; Altstadt, S.; Alvarez-Pol, H.; Ashwood, N.; Aumann, T.; Barr, M.; Beceiro, S.; Bemmerer, D.; Benlliure, J.; Boretzky, K.; Burgunder, G.; Caamano, M.; Caesar, C.; Casarejos, E.; Catford, W.; Chakraborty, S.; Chartier, M.; Chulkov, L.; Cortina-Gil, D.; Datta Pramanik, U.; Diaz, P.; Dillmann, I.; Enders, J.; Ershova, O.; Estrade, A.; Farinon, F.; Fraile, L. M.; Freer, M.; Freudenberger, M.; Galaviz Redondo, D.; Geissel, H.; Gonzalez Diaz, D.; Hagdahl, J.; Heftrich, T.; Heil, M.; Heine, M.; Henriques, A.; Holl, M.; Ignatov, A.; Johansson, H.; Jonson, B.; Kalantar, N.; Knöbel, R.; Kroell, T.; Krücken, R.; Kurcewicz, J.; Labiche, M.; Langer, C.; Le Bleis, T.; Lemmon, R.; Machado, J.; Marganiec, J.; Movsesyan, A.; Najafi, A.; Nilsson, T.; Nociforo, C.; Panin, V.; Pietri, S.; Plag, R.; Prochazka, A.; Rahaman, A.; Rastrepina, G.; Reifarth, R.; Ribeiro, G.; Ricciardi, M. V.; Rigollet, C.; Riisager, K.; Röder, M.; Rossi, D.; Sanchez Del Rio, J.; Savran, D.; Scheit, H.; Simon, H.; Sorlin, O.; Streicher, B.; Taylor, J.; Tengblad, O.; Terashima, S.; Thies, R.; Yasuhiro, T.; Uberseder, E.; van de Walle, J.; Velho, P.; Volkov, V.; Wagner, A.; Wamers, F.; Weick, H.; Weigand, M.; Wheldon, C.; Wilson, G.; Wimmer, C.; Winfield, J.; Woods, P.; Yakorev, D.; Zoric, M.; Zuber, K.
Abstract
An experiment has been performed by the R3B collaboration aiming at the investigation of light neutron-rich nuclei utilizing kinematically complete measurements of reactions at relativistic energies with the R3 B-LAND reaction setup at Cave C. The physics topics to be studied comprise the measurement of astrophysical reaction rates relevant for r-process nucleosynthesis using heavy-ion induced electromagnetic excitation and quasi-free knockout reactions to study the evolution of shell and cluster structures close to and beyond the dripline.
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Contribution to external collection
Katrin Große: GSI Scientific Report 2010, GSI Report 2011-1, Darmstadt: GSI Helmholtzzentrum für Schwerionenforschung Gm, 2011, 166
Permalink: https://www.hzdr.de/publications/Publ-15649
Magnetic phase diagram of multiferroic MnWO4 probed by ultrasound,
Felea, V.; Lemmens, P.; Yasin, S.; Zherlitsyn, S.; Choi, K. Y.; Lin, C. T.; Payen, C.
Abstract
The magnetic phase diagram of multiferroic MnWO4 is studied in magnetic fields up to 60 T using sound velocity and sound attenuation measurements. Anomalies are observed at temperatures TN1 = 7.6 K, TN2 = 12.6 K and TN3 = 13.6 K that separate commensurate antiferromagnetic (AF1) to helical AF2 and commensurate AF3 to paramagnetic phases, respectively. The anomalies are significantly different and shed light on the spin–phonon coupling and evolution of the various order parameters in this multiferroic material. For temperatures below TN2 pronounced field hysteresis effects are also observed in the sound velocity, indicating field-induced transformations. In the temperature dependence of the attenuation we observe anomalies distinctively different from the usual maxima related to relaxation effects. They are attributed to the combination of dispersion effects due to domain walls and the discontinuously changing sound velocity. In total, six different magnetic phases, at various temperatures and fields including a novel high-field phase, are revealed and analyzed.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Journal of Physics: Condensed Matter 23(2011), 216001
DOI: 10.1088/0953-8984/23/21/216001
Cited 18 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15648
Influence of Hydrophobicity on the Surface-Catalyzed Assembly of the Islet Amyloid Polypeptide
Keller, A.; Fritzsche, M.; Yu, Y.-P.; Liu, Q.; Li, Y.-M.; Dong, M.; Besenbacher, F.
Abstract
The islet amyloid polypeptide (IAPP) Is a hormonal factor secreted by the beta-cells in the pancreas. Aggregation of misfolded IAPP molecules and subsequent assembly of amyloid nanofibrils are critical for the development Of type 2 diabetes mellitus. In the physiological environment, amyloid aggregation is affected by the presence of interfaces such as cell membranes. The physicochemical properties of the interface dictates the interaction of the peptide with the surface, i.e., electrostatic and hydrophobic Interactions on hydrophilic and hydrophobic surfaces, respectively. We have studied the Influence of hydrophobicity on the surface-catalyzed assembly of IAPP on ultrasmooth hydrocarbon films grown on ion-beam-modified mica surfaces by atomic force microscopy. The contact angle theta of these surfaces can be tuned continuously in the range from <= 20 degrees to similar to 90 degrees by aging the samples without Significant changes of the chemical composition or the topography of the surface. On hydrophilic surfaces with a theta of similar to 20 degrees, electrostatic interactions Induce the assembly of IAPP nanofibrils, whereas aggregation of large (similar to 2.6 nm) oligomers Is observed at hydrophobic surfaces with a theta of similar to 90 degrees. At intermediate contact angles, the interplay between electrostatic and hydrophobic substrate interactions dictates the pathway of aggregation with fibrillation getting continuously delayed when the contact angle is increased. In addition, the morphology of the formed protofibrils and mature fibrils at intermediate contact angles differs from those observed at more hydrophilic surfaces. These results might contribute to the understanding of the surface-catalyzed assembly of different amyloid aggregates and may also have implications for the technologically relevant controlled synthesis of amyloid nanofibrils of desired morphology.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15647) publication
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ACS Nano 5(2011)4, 2770-2778
DOI: 10.1021/nn1031998
ISSN: 1936-0851
Cited 72 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15647
Long-Acting Lipidated Analogue of Human Pancreatic Polypeptide Is Slowly Released into Circulation
Bellmann-Sickert, K.; Elling, C. E.; Madsen, A. N.; Little, P. B.; Lundgren, K.; Gerlach, L.-O.; Bergmann, R.; Holst, B.; Schwartz, T. W.; Beck-Sickinger, A. G.
Abstract
The main disadvantages of;peptide pharmaceuticals are their rapid degradation and excretion, their low hydrophilicity, and low shelf lifes. These bottlenecks can be circumvented by acylation with fatty acids (lipidation) or polyethylene glycol (PEGylation). Here, we describe the Modification of a human pancreatic polypeptide analogue specific for the human (h)Y2 and hY4 receptor with PEGs of different size and palmitic acid. Receptor specificity was demonstrated by competitive binding studies. Modifications had only small influence on binding affinities and no influence on secondary structure. Both modifications improved pharmacokinetic properties of the hPP analogue in vivo and in vitro,,however, lipidation showed a greater resistance to degradation and excretion than PEGylation, Furthermore, the lipidated peptide is taken up and degraded solely by the liver but not the kidneys. Lipidation resulted in prolonged action of the hPP analogue in respect of reducing food intake in mice after subcutaneous administration. Therefore, the lipidated hPP analogue could constitute a potential new therapeutic agent against obesity.
Involved research facilities
- PET-Center
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Journal of Medicinal Chemistry 54(2011)8, 2658-2667
DOI: 10.1021/jm101357e
ISSN: 0022-2623
Cited 68 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15646
High temperature oxidation resistance of 316 stainless steel doped with Yttrium using intense pulsed plasma beams
Barlak, M.; Piekoszewski, J.; Werner, Z.; Sartowska, B.; Waliś, L.; Starosta, W.; Kierzek, J.; Bocheńska, K.; Heller, R.; Wilhelm, R.; Kolitsch, A.; Pochrybniak, C.; Kowalska, E.
Abstract
Doping stainless steels or iron chromium alloys with oxygen reactive elements like Y and rare earth elements (REE) like Ce, La, Er and others improves their oxidation resistance at high temperature.
There are numerous methods of incorporating REE into steel by surface treatment, e.g.: ion implantation, metalo-organic, chemical vapour deposition, sol-gel coating, pack cementation, screen-printing, molten-salt electrodeposition.
Recently we undertook an attempt to incorporate REE into steels using a new approach based on the use of high intensity pulsed plasma beams (HIPPB). The characteristic feature of this method rely upon the fact that the REE elements are alloyed into the near-surface region of the substrate in its transient liquid state. The preliminary results obtained on AISI 316L steel samples doped with Ce-La in this way and then oxidized in air for 80 hours at 1000°C were encouraging as regards the scales which were thinner, more compact and well adhered.
In the present work we report on the use of yttrium as an active element incorporated into 316 stainless steel using HIPPB. The surface modification of treated samples was performed using 3 pulses with their energy density of 2 Jcm-2 each. Nitrogen was used as a working gas. The yttrium doses accumulated in stainless steel range from 2.34e16 to 1.28e17 cm-2.
The samples are examined by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray diffraction (XRD) and crucially important Rutherford Back Scattering (RBS) measurements and subjected to oxidation in air at a temperature of 1000°C for a period of 100 h.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15645) publication
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Poster
SMMIB2011 - 17th International Conference on Surface Modification of Materials by Ion Beams, 13.-17.09.2011, Harbin, China
Permalink: https://www.hzdr.de/publications/Publ-15645
Scale Resolved Simulations of the OECD/NEA−Vattenfall T-Junction Benchmark
Höhne, T.
Abstract
Mixing of fluids in T-junction geometries is of significant interest for nuclear safety research. The most prominent example is the thermal striping phenomena in piping T-junctions, where hot and cold streams join and turbulently mix, however not completely or not immediately at the T-junction. This results in significant temperature fluctuations near the piping wall, either at the side of the secondary pipe branch or at the opposite side of the main branch pipe. The wall temperature fluctuation can cause cyclical thermal stresses and subsequently fatigue cracking of the wall.
Thermal mixing in a T-junction has been studied for validation of CFD-calculations. A T-junction thermal mixing test was carried out at the Älvkarleby Laboratory of Vattenfall Research and Development (VRD) in Sweden. Data from this test have been reserved specifically for a OECD CFD benchmark exercise. The computational results show that RANS fail to predict a realistic mixing between the fluids. The results were significantly better with scale-resolving methods such as LES, showing fairly good predictions of the velocity field and mean temperatures. The calculation predicts also similar fluctuations and frequencies observed in the model test.
Keywords: T-junction; CFD; mixing; LES; Vattenfall; OECD
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Contribution to proceedings
SMiRT 21, 06.-11.11.2011, New Dehli, India
CD-ROM -
Lecture (Conference)
Smirt21, 06.-11.11.2011, New Dehli, India
Permalink: https://www.hzdr.de/publications/Publ-15644
Monte Carlo simulations of a ClearPET: Scatter and attenuation of gamma rays in various rock formations
Zakhnini, A.; Kulenkampff, J.; Sauerzapf, S.; Lippmann-Pipke, J.; Pietrzyk, U.
Abstract
Positron emission tomography (PET) is applied in geosciences for the visualization of flow and transport processes in various rock formations (GeoPET [1]). Denser rock material requires more demanding and stronger corrections of scatter and attenuation of the gamma rays than in human body tissue. Once the quantification of scatter and attenuation is acquired, correction strategies can be established and the physical limit of the spatial resolution of ~1 mm for the GeoPET method be accomplished. We suggest Monte Carlo (MC) simulations of a ClearPET camera (Raytest) as means for achieving this aim.
We report simulation results of the GeoPET using software GATE (Geant4 Application for Tomographic Emission [2]). The purpose of this investigation is to determine the scatter fraction of gamma rays in various rock formations with different gantry diameter configurations, various Isotopes and different energy windows.
The simulations show that the energy window and increasing gantry diameter are important physical parameters affecting the scatter fraction values in denser material. Reconstructed images from measurements and simulations show good qualitative agreement.
[1] Kulenkampff, J. et al. (2008) Phys. Chem. Earth 33, 937-942.
[2] Jan, S. et al. (2011) Phys. Med. Biol. (56) 881-901.
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
- High Magnetic Field Laboratory (HLD)
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
- PET-Center
- TOPFLOW Facility
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 15643) publication
- DOI: 10.1107/S1600577520014265 is cited by this (Id 15643) publication
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15643) publication
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Poster
2011 IEEE Nuclear Science Symposium and Medical Imaging Conference, 23.-29.10.2011, Valencia, Spain
Permalink: https://www.hzdr.de/publications/Publ-15643
Dampf-Experimente zur Kontaktkondensation und zum Blasenmitriss in der TOPFLOW-Anlage
Seidel, T.; Lucas, D.
Abstract
Die Belastung des Reaktordruckbehälters von Druckwasserreaktoren wird in Thermoschock-Szenarien insbesondere durch Vermischungsvorgänge und von Direktkondensation bestimmt. Die zunehmend auch für Fragestellungen der Reaktorsicherheitsforschung verwendeten CFD-Modelle können diese Phänomene bislang nur mit einigen Einschränkungen abbilden. Die zur Weiterentwicklung der Modelle benötigten Experimente werden gegenwärtig im Helmholtz-Zentrum Dresden-Rossendorf vorbereitet. In einem Bassin werden verschiedene Experimente mit unterkühltem Wasser in Dampfatmosphäre durchgeführt und mit zeitlich und örtlich hoch aufgelösten Messverfahren beobachtet.
Keywords: TOPFLOW; condensation; experiments; bubble entrainment
Involved research facilities
- TOPFLOW Facility
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Contribution to proceedings
Jahrestagung der Kerntechnischen Gesellschaft, 17.-19.05.2011, Berlin, Deutschland
Dampf-Experimente zur Kontaktkondensation und zum Blasenmitriss in der TOPFLOW-Anlage -
Lecture (Conference)
Jahrestagung der Kerntechnischen Gesellschaft, 17.-19.05.2011, Berlin, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15642
Wettability of carbon and silicon caramics induced by their alloying with Ti, Zr, and Cu elements using high intensity pulsed plasma beams
Barlak, M.; Piekoszewski, J.; Werner, Z.; Sartowska, B.; Waliś, L.; Starosta, W.; Kierzek, J.; Bocheńska, K.; Heller, R.; Kolitsch, A.; Pochrybniak, C.; Kowalska, E.
Abstract
Ceramics materials, such as: oxides, nitrides, borides, carbides and carbon are widely used in modern constructions and devices. Their advantages are: low density, high mechanical strength and corrosion resistance at high temperature and favourable performance/weight relationship. However, an application of these materials in joints or in composites with metals is very difficult, because usually the ceramics are non-wettable by liquid metals.
In the present work, we used high intensity plasma pulses technique for the preparation of carbon and silicon carbide surface before the wetting process by liquid copper. The Ti, Zr and Cu plasma was applied to induce the wettability.
The experiments were preceded by thermodynamical considerations. The prepared samples were investigated by sessile-drop tests, SEM observations, EPMA, GXRD analysis and RBS measurements.
The results of Ti and Zr plasma modifications were beneficial and similar to each other. The measured contact angles were below 90°. The results of Cu plasma were unfavorable with contact angles close to 180°.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15641) publication
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Lecture (Conference)
NUTECH-2011, Development and Applications of Nuclear Technologies, 11.-14.09.2011, Krakow, Poland
Permalink: https://www.hzdr.de/publications/Publ-15641
High temperature oxidation resistance of stainless steel doped with Yttrium using ion implantation
Barlak, M.; Piekoszewski, J.; Werner, Z.; Sartowska, B.; Waliś, L.; Starosta, W.; Kierzek, J.; Bocheńska, K.; Heller, R.; Wilhelm, R.; Kolitsch, A.; Pochrybniak, C.; Kowalska, E.
Abstract
The addition of some amount of oxygen reactive elements like Y and rare earth elements (REE) Ce, La, Er and others into stainless steels or iron chromium alloys improves their oxidation resistance at high temperature.
There are numerous methods of incorporation of REE into steel by surface treatment, e.g.: ion implantation, metal organic, chemical vapour deposition, sol-gel coating, pack cementation, screen-printing, molten-salt electrodeposition.
In the present work we intend to use yttrium as an active element which will be incorporated into 304, 316 and 430 stainless using conventional implantation with MEVVA type of Y ion source.
The samples will be examined by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray diffraction (XRD) and crucially important Rutherford Back Scattering (RBS) measurements and subjected to oxidation in air at a temperature of 1000°C for a period 100 h.
Results obtained with the use of HIPPB method and ion implantation will be compared and discussed.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15640) publication
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Lecture (Conference)
NUTECH-2011 International Conference on Development and Applications of Nuclear Technologies, 11.-14.09.2011, Krakow, Poland
Permalink: https://www.hzdr.de/publications/Publ-15640
Ionenimplantation und Unterstützung von PVD Prozessen mit energetischen Ionen als innovativer Technologiefortschritt
Kolitsch, A.
Abstract
Die simultane Kombination verschiedener Ionenenergien mittels Plasma Immersions Ionenimplantation und reaktivem Magnetronsputtern zur Herstellung extrem glatter, superharter und haftfester tribologischer Schichten für Hochtechnologieanwendungen wird beschrieben
Keywords: PBII; PIII; TiN; cBN; PVD; super hard coatings
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15639) publication
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Invited lecture (Conferences)
Oberflächenmodifikation von Werkstoffen, 13.05.2011, Zittau, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15639
Neon identifies two billion year old fluid component in Kaapvaal Craton
Lippmann-Pipke, J.; Sherwood Lollar, B.; Niedermann, S.; Stroncik, N. A.; Naumann, R.; van Heerden, E.; Onstott, T. C.
Abstract
We analysed shallow (to ~1 km) and deep fracture waters (to > 3 km) from the Witwatersrand Basin, South Africa for their noble gas isotopic composition. Their neon signature clearly differentiates a group of typical crustal fluids from another one with a significantly enriched nucleogenic neon signal with the highest 21Ne/22Ne ratios (0.160 +/- 0.003) ever reported in groundwater [1]. Fluid inclusions in adjacent rocks yield even higher 21Ne/22Ne ratios between 0.219 and 0.515, consistent with an extrapolated 21Ne/22Ne value of 3.3 +/- 0.2 at 20Ne/22Ne = 0. We show that this enriched nucleogenic neon end-member represents a fluid component that was produced in the fluorine-depleted Archaean formations and trapped in fluid inclusions > 2 Ga ago [1]. The observation of enriched nucleogenic neon signatures in deep fracture water implies the release of this billion year old neon component from the fluid inclusions and its accumulation in exceptionally isolated fracture water systems. The observed association of this Archaean neon signature with H2-hydrocarbon-rich geogases of proposed abiogenic origin [2] dissolved in the same deep groundwater suggests that the fracture systems have also allowed for the accumulation of various products of water-rock reactions throughout geologic times. One of these fracture systems contained a chemolithotrophic, single species ecosystem surviving on radiolytically produced H2 and sulfate completely independent of the surface photosphere [3,4].
[1] Lippmann-Pipke et al. 2011 Chem. Geol. 283, 287-296
[2] Sherwood Lollar et al. 2002 Nature 416(6880) 522-524
[3] Lin L.-H. et al. 2006 Science 314(5798), 479-482
[4] Chivian, D. et al. 2008 Science 322(5899), 275-278
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Lecture (Conference)
Goldschmidt 2011, 14.-19.08.2011, Prague, Czech Republic
Permalink: https://www.hzdr.de/publications/Publ-15638
Steinalte Wässer in Südafrikas Goldminen
Lippmann-Pipke, J.
Abstract
Ein internationales Forscherteam untersucht Wasserproben aus den tiefsten Bergwerken der Welt. Eine Wasserkomponente entpuppt sich als ein "urzeitliches" Signal und belegt die außerordentliche Isolation dieser tiefen, mikrobiell besiedelten Wasserreservoire.
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Lecture (others)
Lange Nacht der Wissenschaften, 01.07.2011, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15637
Influence of a point source motion in PET images and its compensation
Laube, K.; Fiedler, F.; Schöne, S.; Bert, C.; Enghardt, W.
Keywords: in-beam PET; motion
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Contribution to external collection
in: GSI Scientific Report 2010, Darmstadt: GSI Helmholtzzentrum für Schwerionenforschung, 2011, 470
Permalink: https://www.hzdr.de/publications/Publ-15636
Improved fingerprinting of Melos obsidian using three complementary analytical techniques
Eder, F.; Neelmeijer, C.; Pearce, N. J. G.; Bichler, M.; Merchel, S.
Abstract
The natural volcanic glass obsidian was one of the most appreciated materials of ancient man for cutting tools and has been found in many locations far away from any natural source. Reliable provenancing by means of its highly specific chemical composition, the “chemical fingerprint”, can provide information about economy, policy and the social system of ancient societies.
The application of three complementary analytical techniques enables both a maximum element spectrum and a comparison of the chemical compositions to provide the actual degree of the re-liability of the analytical results.
This approach reveals the most characteristic “chemical fingerprint“ and allow us to decide which least invasive analytical method should be chosen for the analysis of an archaeological artefact most likely stem from Melos by three different methods:
- Neutron Activation Analysis (NAA)
- Ion Beam Analysis (IBA) comprising of Proton Induced X-ray Emission (PIXE), Proton Induced Gamma-ray Emission (PIGE) and Rutherford Backscattering Spectrometry (RBS)
- Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)
These investigations are part of a joint project to apply analytical techniques mentioned to check the self-consistency of the analytical results and to reveal the most characteristic “chemical fin-gerprint” of each available natural obsidian source in Europe. This knowledge should enable to decide which least invasive analytical method should be chosen for the analysis of a specific archaeological artefact on a case-by-case basis.
Keywords: ion beam analysis; chemical fingerprint
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15635) publication
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Poster
3. Österreichischer Archäometriekongress, 13.-14.05.2011, Salzburg, Österreich
Permalink: https://www.hzdr.de/publications/Publ-15635
Volcanic glass under fire - A comparison of three complementary analytical techniques
Eder, F.; Neelmeijer, C.; Pearce, N. J. G.; Bichler, M.; Merchel, S.
Abstract
Produced by fiery volcanic eruptions obsidian solidified as natural glass and was again under fire at the three different research facilities. Obsidian, also called the “Stone Age black gold” was an important raw material for cutting tools during prehistoric time and has been found by research-ers at great distances from potential natural sources. Reliable provenancing by means of its highly specific chemical composition, the “chemical fingerprint”, can provide information about economy, policy and the social system of ancient societies.
The application of three complementary analytical techniques enables both a maximum element spectrum and a comparison of the chemical compositions to provide the actual degree of the re-liability of the analytical results. This approach allows us to assess accuracy and precision of ar-chaeometric elemental analyses by three different methods:
- Neutron Activation Analysis (NAA)
- Ion Beam Analysis (IBA) comprising of Proton Induced X-ray Emission (PIXE), Proton Induced Gamma-ray Emission (PIGE) and Rutherford Backscattering Spectrometry (RBS)
- Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)
These investigations are part of a joint project to apply analytical techniques mentioned to check the self-consistency of the analytical results and to reveal the most characteristic “chemical fin-gerprint” of each available natural obsidian source in Europe. This knowledge should enable to decide which least invasive analytical method should be chosen for the analysis of a specific archaeological artefact on a case-by-case basis.
Keywords: ion beam analysis; chemical fingerprint
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15634) publication
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Poster
16. Tagung Festkörperanalytik, 04.-06.07.2011, Wien, Österreich
Permalink: https://www.hzdr.de/publications/Publ-15634
Korrosionsmechanismus von verzinktem Stahl in Borsäure
Hoffmann, W.; Kryk, H.
Abstract
Bei einem Kühlmittelverluststörfall eines Druckwasserreaktors (DWR) können sich in der Anfangsphase an den Sumpfansaugsieben Mineralwolleablagerungen aus dem Isolationsmaterial bilden und dadurch die Notkühlung beeinträchtigen. Das borsäurehaltige Primärkühlmittel verursacht eine Korrosion an Einbauten im Containment, die überwiegend aus feuerverzinktem Stahl bestehen. Feste Korrosionsprodukte bewirken durch Anlagerung an den Mineralwolleablagerungen einen Anstieg des Differenzdrucks über den Sumpfansaugsieben, der bis zur Blockade und dem Ausfall der Notkühlung führen kann. Ausgehend vom Schichtaufbau der Feuerverzinkung konnte der Ablauf der Korrosion aufgeklärt werden, wobei zunächst lösliche Korrosionsprodukte des Zinks entstehen und erst nach Freilegung von Stahl Rost gebildet wird, der sich am Faserbett anlagern kann. Die Ergebnisse, die auf den Analysen der Lösungen, der Ablagerungen auf den Faserbetten und den Metallproben nach Ende der Versuche beruhen, stehen in Übereinstimmung mit dem Differenzdruckanstieg als technisch wichtigen Parameter. Die anfangs starke Korrosion unter Bildung von Zinkionen verursacht eine Zunahme des pH-Werts, die aber zu einer Verringerung der Korrosionsrate führt. Entscheidend für den Korrosionsverlauf sind neben einem ausreichenden Angebot an Zinkoberfläche besonders die Strömungsverhältnisse und die Zusammensetzung des Primärkühlmittels bei lokaler Freilegung des Basismaterials.
Keywords: LWR; LOCA; corrosion; hot-dip galvanised steel; zinc; boric acid
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Lecture (Conference)
Fachkolloquium "Partikelströmung", 17.-18.03.2011, Zittau und Dresden, Deutschland -
Contribution to proceedings
Fachkolloquium "Partikelströmung", 17.-18.03.2011, Zittau und Dresden, Deutschland
CD-ROM
Permalink: https://www.hzdr.de/publications/Publ-15633
Exploring the mobility of actinyl ions in the biogeosphere: a spectroscopic and theoretical study of U(VI) complexes with organic phosphate groups
Foerstendorf, H.; Tsushima, S.; Brüning, S.; Li, B.
Abstract
The high affinity of uranyl(VI) ions to distinct functional groups of biomolecules is considered to contribute decisively to the migration behaviour of these metal ions in the biogeosphere [1]. In particular, organic phosphate groups are predestined to form actinide complexes at a physiologically relevant pH level [2]. Because the phosphorylated sites of biomolecules often represent a key role in their proper physiological function, the study on the complexation is of great significance.
In this work, U(VI) complexes of phosphorylated amino acids, namely p-serine and p-tyrosine, were investigated by vibrational spectroscopy serving as model compounds for more complex systems. The spectra obtained demonstrate the high affinity of the actinyl ion to phosphate groups. Contributions from the carboxyl and amino groups to the U(VI) complexes can be neglected.
These results are compared with spectra obtained from our recent investigation with a naturally occurring highly phosphorylated protein, phosvitin [3]. The spectral homologies confirm the suggestion that U(VI) is preferentially bound by organic phosphate groups under physiologically relevant conditions.
The derivation of molecular structures from vibrational spectra can be supported by theoretical approaches, such as density functional theory (DFT) calculations. A series of calculations was performed to reproduce the vibrational spectral data focusing on the frequency range of the vibrational modes of the phosphate groups. A comparison with the experimental data provides additional structural information on a molecular level.
[1] Van Horn, J. D. et al. (2006) Coord. Chem. Rev. 250, 765-775. [2] Barkleit, A. et al. (2008) Dalton Trans., 2879-2886. [3] Li, B. et al. (2010) J. Inorg. Biochem. 104, 718-725.
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Lecture (Conference)
Goldschmidt 2011, 14.-19.08.2011, Prague, Czech Republic -
Contribution to proceedings
Goldschmidt 2011, 14.-19.08.2011, Prague, Czech Republic
Mineralogical Magazine 75(3), Twickenham: Mineralogical Society of Great Britain and Ireland, 0026-461X, 856-856
Downloads
Permalink: https://www.hzdr.de/publications/Publ-15632
The use of prompt gamma-rays for in-vivo dosimetry at therapeutic proton and ion beams
Fiedler, F.; Dersch, U.; Golnik, C.; Kormoll, T.; Müller, A.; Rohling, H.; Schöne, S.; Enghardt, W.
Keywords: in vivo dosimetry; in-beam SPECT; ion therapy monitoring; proton therapy monitoring; dose monitoring
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Contribution to proceedings
2011 IEEE Nuclear Science Symposium an Medical Imaging Conference, 23.-29.10.2011, Valencia, Spain -
Lecture (Conference)
2011 IEEE Nuclear Science Symposium an Medical Imaging Conference, 23.-29.10.2011, Valencia, Spain
Permalink: https://www.hzdr.de/publications/Publ-15630
Local structure and charge distribution in mixed uranium-americium oxides: effects of oxygen potential and Am content
Prieur, D.; Martin, P. M.; Jankowiak, A.; Gavilan, E.; Scheinost, A. C.; Herlet, N.; Dehaudt, P.; Blanchart, P.
Abstract
Partitioning and Transmutation (P&T) of minor actinides (MA) is currently studied to reduce the nuclear waste inventory. In this context, the fabrication of MA bearing materials is of great interest to achieve an effective recycling of these highly radioactive elements. In order to ensure the inpile behavior, these fuels have to respect several criteria including preservation of the fluorite structure and defined oxygen to metal ratio (O/M). In the case of Am bearing materials, such as U1-yAmyO2±x (y=0.10, 0.15, 0.20), the O/M determination is quite challenging using conventional methods (TGA, XRD) due to the particular Am thermodynamic properties. Despite the lack of experimental data in the U-Am-O system, thermodynamical modeling are currently developed to effectively assess the O/M ratio. In this work, the O/M ratios were calculated for various oxygen potentials using the cation molar fraction determined by XAS measurements. These results are an important addition to the experimental data available for the U-Am-O system. Moreover, XRD and XAS indicated that the fabrication of fluorite U1-yAmyO2±x solid solution can be achieved for all Am content and oxygen potentials investigated. Based on the molar fraction, a description of the solid solution was proposed depending on the considered sintering conditions. Finally, the occurrence of an expected charge compensation mechanism between Am(+III) and U(+V) was pointed out.
Keywords: Partitioning; Transmutation; Americium; XAFS
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 15629) publication
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Inorganic Chemistry 50(2011), 12437-12445
DOI: 10.1021/ic200910f
Cited 81 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15629
Cyclotron resonance mass and Fermi energy pinning in the In(AsN) alloy
Drachenko, O.; Patanè, A.; Kozlova, N. V.; Zhuang, Q. D.; Krier, A.; Eaves, L.; Helm, M.
Abstract
We report cyclotron resonance (CR) experiments on the midinfrared alloy InAs1-xNx grown on GaAs with x from 0% to 1.9%. Using magnetic fields up to 60 T and terahertz photon sources from 3 to 30 THz, we determine the dependence on x of the electron density and CR mass. The increase in the carrier density with increasing x is accompanied by a redshift in the interband photoluminescence emission and is explained in terms of the pinning of the Fermi level to its value at x = 0. The high carrier densities (similar to 10(18) cm(-3)) at x similar to 1% give rise to a CR mass that is only weakly dependent on the excitation energy, significantly weaker than that in InAs. (C) 2011 American Institute of Physics.
Keywords: Nitrogen; Cyclotron resonance; effective mass
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Applied Physics Letters 98(2011)16, 162109-1-162109-3
DOI: 10.1063/1.3583378
Cited 12 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15628
Transparent target for ultrafast electron beam tomography
Hampel, U.; Barthel, F.; Bieberle, M.; Sturzel, T.
Abstract
In electron beam tomography a rotating X-ray source is generated by electromagnetic scanning of a high-power electron beam across a spatially fixed circular metal target. The X-rays passing the object of investigation are registered by a circular fast X-ray detector array. A basic problem associated with this scanning principle is the angular overlap of the X-ray focal spot path and the detector, which is required for image reconstruction. Therefore, the X-ray production target and the detector array are commonly arranged with some axial displacement. This displacement may produce image artifacts because X-rays are not longer confined to a transversal plane. We propose a novel transparent X-ray target, which fully solves this problem. The new target concept has been practically tested with respect to thermal behavior and electron beam resistance. Its successful application in an experimental tomography setup is demonstrated.
Keywords: ultrafast x-ray tomography; transparent target
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Nuclear Instruments and Methods in Physics Research A 635(2011)1, 8-12
DOI: 10.1016/j.nima.2011.01.075
ISSN: 0168-9002
Cited 4 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15627
Liquid metal experiments on the Tayler instability
Seilmayer, M.; Gerbeth, G.; Gundrum, T.; Stefani, F.; Weier, T.; Gellert, M.; Rüdiger, G.
Abstract
In the kink-type Tayler instability (TI) a toroidal magnetic field becomes unstable against non-axisymmetric perturbations for a sufficiently large field amplitude. The TI has been discussed as a possible ingredient of the solar dynamo and a source of the helical structures in cosmic jets. It has also to be considered as a limiting criterion for the size of large scale liquid metal batteries. We report on first TI experiments with a cylindrical column of GaInSn to which electrical currents of up to 8 kA are applied. We present results of external magnetic field measurements that indicate the occurrence of the TI.
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Lecture (Conference)
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France -
Contribution to proceedings
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France
Proceedings of the 8th PAMIR International Conference on Fundamental and Applied MHD, 217-221
Permalink: https://www.hzdr.de/publications/Publ-15626
New prospects for the Riga dynamo: Prediction of magnetic energy oscillations for a modified flow field
Stefani, F.; Gerbeth, G.; Gailitis, A.
Abstract
Starting from the present version of the Riga dynamo experiment with its rotating magnetic eigenfield dominated by a single frequency we ask for those flow modifications that would allow for a non-trivial magnetic field behaviour in the saturation regime. Increasing the ratio of azimuthal to axial flow velocity, numerically we obtain energy oscillations with a frequency below the eigenfrequency of the magnetic field. These new oscillations are identified as magneto-inertial waves that result from a slight imbalance of Lorentz and inertial forces. Increasing the azimuthal velocity further, or increasing the total magnetic Reynolds number, we find transitions to a chaotic behaviour of the dynamo.
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Contribution to proceedings
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France
Proceedings of the 8th PAMIR International Conference on Fundamental and Applied MHD, 121-125 -
Poster
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France
Permalink: https://www.hzdr.de/publications/Publ-15625
DRESDYN - A new facility for MHD-experiments with liquid sodium
Stefani, F.; Eckert, S.; Gerbeth, G.; Gundrum, T.
Abstract
The DREsden Sodium facility for DYNamo and thermohydraulic studies (DRESDYN) is intended to become a platform both for large scale experiments related to geo- and astrophysics as well as for safety and thermohydraulic studies related to liquid metal batteries and sodium fast reactors. The most ambitious parts of DRESDYN are a homogeneous dynamo driven solely by precession and a large Tayler-Couette like experiment for the combined investigation of the magnetorotational instability and the Tayler instability. In the talk we give a short summary of the previous achievements, and we delineate the next steps for the realization of DRESDYN.
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Lecture (Conference)
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France -
Contribution to proceedings
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France
Proceedings of the 8th PAMIR International Conference on Fundamental and Applied MHD, 115-119
Permalink: https://www.hzdr.de/publications/Publ-15624
Alfvén wave experiments with liquid Rubidium at the Dresden High Magnetic Field Laboratory
Gundrum, T.; Arnold, F.; Forbriger, J.; Gerbeth, G.; Herrmannsdörfer, T.; Putzke, C.; Stefani, F.
Abstract
We report on Alfvén wave experiments with liquid Rubidium at the Dresden High Magnetic Field Laboratory (HLD). With pulsed magnetic fields reaching up 62 T we enter the interesting region where the Alfvén speed crosses the sound speed.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Contribution to proceedings
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France
Proceedings of the 8th PAMIR International Conference on Fundamental and Applied MHD, 411-415 -
Poster
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France
Permalink: https://www.hzdr.de/publications/Publ-15623
On the formation of Taylor-Görtler vortices in RMF-driven spin-up flows
Vogt, T.; Grants, I.; Räbiger, D.; Eckert, S.; Gerbeth, G.
Abstract
This paper is concerned with a liquid metal flow driven by a rotating magnetic field inside a stationary cylinder. We consider especially the secondary meridional flow during the time the fluid spins up from rest. The developing flow is investigated experimentally and by direct numerical simulations. The vertical profiles of the axial velocity are measured by means of the ultrasound Doppler velocimetry. Evolving instabilities in form of Taylor-Görtler vortices have been observed just above the instability threshold. The transition to a three-dimensional flow in the side layers results from the advection or a precession and splitting of the Taylor-Görtler vortex rings. The numerical simulations agree very well with the flow measurements.
Keywords: rotating magnetic field; Taylor-Görtler vortex; flow measurements; ultrasound Doppler method; direct numerical simulation
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Experiments in Fluids 52(2012)1, 1-10
DOI: 10.1007/s00348-011-1196-x
Cited 14 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15622
Tayler instability influenced by internal heating
Gellert, M.; Rüdiger, G.; Schultz, M.; Stefani, F.; Seilmayer, M.
Abstract
The kink-type instability of a toroidal magnetic field, also known as Tayler instability (TI) is a current-driven instability of a strong enough field due to non-axisymmetric perturbations. In astrophysical context the TI has been discussed as a principal ingredient of a dynamo mechanism (Taylor-Spruit dynamo). It is also a possible source of helicity, in particular of helical structures in galactic jets and outflows. TI is also widely used as a mechanism to enhance angular momentum transport in star evolution models even if there is not yet observational evidence for its existence. Nonetheless an ongoing laboratory experiment in cylindrical geometry indeed shows that TI exists in liquid metal flows influenced by a strong axial current.
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Lecture (Conference)
17th International Couette-Taylor Workshop, 25.-27.07.2011, Leeds, United Kingdom
Permalink: https://www.hzdr.de/publications/Publ-15621
Ultraschall-Doppler-Array-Meßsystem zur flächenhaften Untersuchung von Flüssigmetallströmungen
Büttner, L.; Franke, S.; Räbiger, D.; Eckert, S.; Czarske, J.
Abstract
Die Untersuchung des Strömungsverhaltens von flüssigen Metallen besitzt sowohl in der Grundlagenforschung als auch in der industriellen Anwendung eine besondere Bedeutung. Dieses liegt zum einen an den Eigenschaften des Fluids selbst, zum anderen an der interessanten Möglichkeit, daß sich diese Strömungen aufgrund ihrer hohen elektrischen Leitfähigkeit aktiv durch elektromagnetische Kräfte beeinflussen lassen. Für die Kristallzucht wird beispielsweise der Einsatz rotierender oder wandernder Magnetfelder verfolgt, um eine gute Durchmischung und damit eine hohe Homogenität der Schmelze zu erreichen. Die dort auftretenden Strömungsstrukturen können relativ komplex werden, was wiederum eine örtlich hochauflösende, bildgebende Meßtechnik erfordert, um z. B. numerische Simulationen zu validieren. Es wird ein bildgebendes Ultraschall-Meßsystem vorgestellt, daß durch Einsatz segmentierter Wandler und deren weitgehendem Parallelbetrieb sowohl eine hohe Zeit- als auch eine hohe Ortsauflösung ermöglicht. Kernelemente des Systems sind zwei orthogonal angeordnete Ultraschallwandler-Arrays, deren einzelne Wandlerelemente durch eine mikroprozessorgesteuerte Schaltmatrix nach einem speziellen Muster angesteuert und ausgelesen werden.
Keywords: flow measurements; flow mapping; ultrasound Doppler method; sensor array
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Lecture (Conference)
GALA 2011, 06.-08.09.2011, Ilmenau, Deutschland -
Contribution to proceedings
GALA 2011, 06.-08.09.2011, Ilmenau, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15620
Oscillating melt flow driven by a rotating magnetic field in a cylindrical column with oxidized surface
Eckert, S.; Shatrov, V.; Zhang, C.; Gerbeth, G.
Abstract
This paper considers the situation where the liquid metal flow with a free surface covered by an oxide layer is driven by a rotating magnetic field. The cylindrical configuration was investigated in an experiment accompanied by numerical simulations. The oxide layer feels the effect of the viscous force arising from the moving liquid beneath and the friction force from the side walls. A complex interaction occurs if both forces are in the same order of magnitude. Our measurements demonstrate that the occurrence of the oxide layer may lead to an unexpected oscillating behaviour of the bulk flow. Our numerical model was shown to be able to reproduce essential features of the phenomenon in a qualitative way.
Keywords: electromagnetic stirring; rotating magnetic field; flow measurements; ultrasound Doppler method
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Lecture (Conference)
8th International PAMIR conference on fundamental and applied MHD, 05.-06.09.2011, Borgo, France -
Contribution to proceedings
8th International PAMIR conference on fundamental and applied MHD, 05.-09.09.2011, Borgo, France
Proc. of the 8th International PAMIR conference, 611-615
Permalink: https://www.hzdr.de/publications/Publ-15619
Liquid metal modeling of continuous steel casting – the LIMMCAST programme at HZDR
Gerbeth, G.; Eckert, S.; Stefani, F.; Timmel, K.; Miao, X.; Wondrak, T.; Lucas, D.
Abstract
We present the new experimental facility LIMMCAST for modelling the continuous casting process of steel using the alloy SnBi at temperatures of 200-400°C. In addition, a smaller set-up Mini-LIMMCAST operates with the room-temperature liquid alloy GaInSn. First results will be presented covering the following phenomena: fully contactless electromagnetic tomography of the flow in the mould, mould flow monitoring by an array of ultrasonic sensors, analysis of the flow in the mould under the influence of an electromagnetic brake and the injection of argon bubbles through the stopper rod. Numerical simulations using ANSYS-CFX were performed which basically confirm the measuring results.
Keywords: continuous casting; model experiments; flow measurements; electromagnetic brake; numerical simulation
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Invited lecture (Conferences)
8th International PAMIR conference on fundamental and applied MHD, 05.-09.09.2011, Borgo, France -
Contribution to proceedings
8th International PAMIR conference on fundamental and applied MHD, 05.-09.09.2011, Borgo, France
Proc. of the 8th International PAMIR conference, 635-639
Permalink: https://www.hzdr.de/publications/Publ-15618
A liquid metal experiment on the Tayler instability
Seilmayer, M.; Gerbeth, G.; Gundrum, T.; Stefani, F.; Weier, T.; Gellert, M.; Rüdiger, G.
Abstract
We describe an experimental set-up for the investigation of the Tayler instability (TI), we show first results, and we discuss the possible relevance of the TI for large-scale liquid metal batteries as they are presently under consideration as cheap means for the storage of renewable energies.
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Lecture (Conference)
17th International Couette-Taylor Workshop, 25.-27.07.2011, Leeds, United Kingdom
Permalink: https://www.hzdr.de/publications/Publ-15617
Experiments on dynamo action, magnetorotational instability, and Alfvén waves
Stefani, F.
Abstract
At the end of 1999, the dynamo experiments in Riga and Karlsruhe initiated a period of strong activity to simulate the origin and the action of cosmic magnetic fields in the liquid metal laboratory. With main focus on our own efforts, we summarize the recent liquid metal experiments on homogeneous dynamo action and related magnetic instabilities. We delineate our plans for a new liquid sodium facility that will comprise a large scale dynamo experiment based on precession, and a Taylor-Couette experiment for the combined investigation of the magnetorotational instability and of the kink-type Tayler instability. We further discuss the capabilities of alkali metal experiments to study Alfvén waves in a parameter region where the Alfvén speed crosses the sound speed.
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Invited lecture (Conferences)
478th Heraeus Seminar: Fusion and Astrophysical Plasmas, 18.-20.04.2011, Bad Honnef, Germany
Permalink: https://www.hzdr.de/publications/Publ-15616
Dynamic effects induced by renormalization in anisotropic pattern forming systems
Keller, A.; Nicoli, M.; Facsko, S.; Cuerno, R.
Abstract
The dynamics of patterns in large two-dimensional domains remains a challenge in non-equilibrium phenomena. Often it is addressed through mild extensions of one-dimensional equations. We show that full 2D generalizations of the latter can lead to unexpected dynamical behavior. As an example we consider the anisotropic Kuramoto-Sivashinsy equation, that is a generic model of anisotropic pattern forming systems and has been derived in different instances of thin film dynamics. A rotation of a ripple pattern by 90◦ occurs in the system evolution when nonlinearities are strongly suppressed along one direction. This effect originates in non-linear parameter renormalization at different rates in the two system dimensions, showing a dynamical interplay between scale invariance and wavelength selection. Potential experimental realizations of this phenomenon are identified.
Keywords: anisotropy; renormalization; Kuramoto-Sivashinsky euqation; pattern formation
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Physical Review E 84(2011), 015202(R)
DOI: 10.1103/PhysRevE.84.015202
Cited 11 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15615
Tuning the hydrophobicity of mica surfaces by hyperthermal Ar ion irradiation
Keller, A.; Fritzsche, M.; Ogaki, R.; Bald, I.; Facsko, S.; Dong, M. D.; Kingshott, P.; Besenbacher, F.
Abstract
The hydrophobicity of surfaces has a strong influence on their interactions with biomolecules such as proteins. Therefore, for in vitro studies of bio-surface interactions model surfaces with tailored hydrophobicity are of utmost importance. Here, we present a method for tuning the hydrophobicity of atomically flat mica surfaces by hyperthermal Ar ion irradiation. Due to the sub-100 eV energies, only negligible roughening of the surface is observed at low ion fluences and also the chemical composition of the mica crystal remains almost undisturbed. However, the ion irradiation induces the preferential removal of the outermost layer of K+ ions from the surface, leading to the exposure of the underlying aluminosilicate sheets which feature a large number of centers for C adsorption. The irradiated surface thus exhibits an enhanced chemical reactivity toward hydrocarbons, resulting in the adsorption of a thin hydrocarbon film from the environment. Aging these surfaces under ambient conditions leads to a continuous increase of their contact angle until a fully hydrophobic surface with a contact angle > 80 degrees is obtained after a period of about 3 months. This method thus enables the fabrication of ultrasmooth biological model surfaces with precisely tailored hydrophobicity.
Keywords: atomic-force-microscopy; ray photoelectron-spectroscopy; highly-charged ions; sputtering yields; solid-surfaces; film growth; energy; plasma; adsorption; argon
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15614) publication
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Journal of Chemical Physics 134(2011)10, 104705
DOI: 10.1063/1.3561292
Cited 38 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15614
Synthesis, characterization and biological evaluation of [188Re(N)(cys∼)(PNP)]+/0 mixed-ligand complexes as prototypes for the development of 188Re(N)-based target-specific radiopharmaceuticals
Thieme, S.; Agostini, S.; Bergmann, R.; Pietzsch, J.; Pietzsch, H.-J.; Carta, D.; Salvarese, N.; Refosco, F.; Bolzati, C.
Abstract
We report on an efficient procedure for the preparation of [188Re(N)(PNP)]-based complexes (where PNP is diphosphinoamine) useful in the development of target-specific radiopharmaceuticals. The radiochemical yield of the compounds was optimized considering such reaction parameters as nature of the nitrido nitrogen donor, reaction times and pH level. The chemical identity of the 188Re agents was determined by high-performance liquid chromatography comparison with the corresponding well-characterized cold Re compounds. 188Re(N) mixed compounds have been evaluated with regard to stability toward transchelation with GSH and degradation by serum enzymes. The clearance of selected radiocompounds from normal tissues and their in vivo stability were evaluated in rats by biodistribution and imaging studies. [188Re(N)(cys∼)(PNP)]+/0 mixed-ligand compounds were efficiently prepared in aqueous solution from perrhenate using a multistep procedure based on the preliminary formation of the labile 188ReIII–EDTA species, which easily undergo oxidation/ligand exchange reaction to afford the [188ReV≡N]2+ core in the presence of dithiocarbazate. The final mixed-ligand compounds were obtained, at 100°C, by adding the two bidentate ligands to the buffered [188ReV≡N]2+ solution (pH 3.2–3.6). However, a relatively high amount of cys∼ ligand was required to obtain a quantitative radiochemical yield. The complexes were stable toward reoxidation to perrhenate and ligand exchange reactions. In vivo studies showed rapid distribution and elimination of the complexes from the body. No specific uptakes in sensitive tissues/organs were detected. A positive correlation of the distribution of the complexes estimated with biodistribution studies (%ID) and with micro-SPECT semiquantification imaging analysis (standard uptake values) was observed. These results support the possibility of applying [188Re(N)(PNP)] technology to the preparation of target-specific agents.
Keywords: Rhenium; Technetium; 188Re-nitrido; Diphosphinoamines; Peptide; Therapy
Involved research facilities
- PET-Center
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Nuclear Medicine and Biology 38(2011), 399-415
DOI: 10.1016/j.nucmedbio.2010.09.006
Cited 13 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15613
Feasibility and performance of novel software to quantify metabolically active volumes and 3D partial volume corrected SUV and metabolic volumetric products of spinal bone marrow metastases on 18F-FDG-PET/CT.
Torigian, D. A.; Lopez, R. F.; Alapati, S.; Bodapati, G.; Hofheinz, F.; van den Hoff, J.; Saboury, B.; Alavi, A.
Abstract
Our aim was to assess feasibility and performance of novel semi-automated image analysis software called ROVER to quantify metabolically active volume (MAV), maximum standardized uptake value-maximum (SUVmax), 3D partial volume corrected mean SUV (cSUVmean), and 3D partial volume corrected mean MVP (cMVPmean) of spinal bone marrow metastases on fluorine-18 fluorodeoxyglucose-positron emission tomography/computerized tomography (18F-FDG-PET/CT). We retrospectively studied 16 subjects with 31 spinal metastases on FDG-PET/CT and MRI. Manual and ROVER determinations of lesional MAV and SUVmax, and repeated ROVER measurements of MAV, SUVmax, cSUVmean and cMVPmean were made. Bland-Altman and correlation analyses were performed to assess reproducibility and agreement. Our results showed that analyses of repeated ROVER measurements revealed MAV mean difference (D)=-0.03±0.53cc (95% CI(-0.22, 0.16)), lower limit of agreement (LLOA)=-1.07cc, and upper limit of agreement (ULOA)=1.01cc; SUVmax D=0.00±0.00 with LOAs=0.00; cSUVmean D=-0.01±0.39 (95% CI(-0.15, 0.13)), LLOA=-0.76, and ULOA=0.75; cMVPmean D=-0.52±4.78cc (95% CI(-2.23, 1.23)), LLOA=-9.89cc, and ULOA=8.86cc. Comparisons between ROVER and manual measurements revealed volume D= -0.39±1.37cc (95% CI (-0.89, 0.11)), LLOA=-3.08cc, and ULOA=2.30cc; SUVmax D=0.00±0.00 with LOAs=0.00. Mean percent increase in lesional SUVmean and MVPmean following partial volume correction using ROVER was 84.25±36.00% and 84.45±35.94% , respectively. In conclusion, it is feasible to estimate MAV, SUVmax, cSUVmean, and cMVPmean of spinal bone marrow metastases from 18F-FDG-PET/CT quickly and easily with good reproducibility via ROVER software. Partial volume correction is imperative, as uncorrected SUVmean and MVPmean are significantly underestimated, even for large lesions. This novel approach has great potential for practical, accurate, and precise combined structural-functional PET quantification of disease before and after therapeutic intervention.
Keywords: Bone marrow metastasis; 18F-FDG-PET/CT; Partial volume correction; Globval disease assessment; Quantitative analysis; Software analysis
Involved research facilities
- PET-Center
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Hellenic Journal of Nuclear Medicine 14(2011)1, 8-14
ISSN: 1108-1430
Permalink: https://www.hzdr.de/publications/Publ-15612
Elektrische Aktivierung von Dotanden durch Lasertempern oberhalb der Löslichkeitsgrenze
Bürger, D.
Abstract
Die Aktivierung flacher Dotanden stellt einen wichtigen Prozess in der Siliziumtechnologie dar. Typische Dotiermaterialien, wie z. B. Bor, Phosphor, Arsen oder Antimon, besitzen eine sehr hohe Löslichkeit in Silizium. Deswegen können in Silizium hohe Dotierkonzentrationen mit konventionellen Ausheilmethoden in der festen Phase auf der Millisekunden-Zeitskale erreicht werden.
Neuartige, mit Übergangsmetallen dotierte Halbleiter, benötigen für die gewünschte ferromagnetische Kopplung Dotierkonzentrationen weit oberhalb der geringen Löslichkeit magnetischer Dotanden. Ausreichend hohe Dotierkonzentrationen magnetischer Dotanden werden mittels Lasertempern in der flüssigen Phase erreicht. Lasertempern ist ein Prozess, welcher unter thermodynamischen Nichtgleichgewichtsbedingungen auf der ns-Zeitskale stattfindet und eine Diffusion der Dotanden extrem unterdrückt.
In dem Vortrag werden typische Anwendungsgebiete der Lasertemperung vorgestellt und ein Blick auf den aktuellen Stand der Forschung auf dem Gebiet der Lasertemperung zur Herstellung ferromagnetischer Halbleiter geworfen.
Keywords: Lasertemperung; Löslichkeit; Aktivierung
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15611) publication
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Lecture (Conference)
29. Treffen der Nutzergruppe Heißprozesse und RTP, 12.05.2011, Erlangen, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15611
Photoluminescence dynamics in GaAs/AlGaAs quantum wells under pulsed intersubband excitation
Zybell, S.; Schneider, H.; Winnerl, S.; Wagner, M.; Köhler, K.; Helm, M.
Abstract
We investigate the time-resolved photoluminescence (PL) dynamics of an undoped GaAs/AlGaAs multiple quantum well under mid-infrared (MIR) irradiation. A time-delayed MIR laser pulse from a free electron laser, tuned to the intersubband transition energy of the quantum well, induces temporal quenching of the PL intensity with subsequent recovery. The experimental data can be accurately described by a simple rate-equation model, which accounts for the cooling of the non-radiative states to radiative states. By performing polarization sensitive measurements, we are able to discriminate the contributions of free-carrier absorption from that of intersubband absorption, where the latter is about 50 times more efficient.
Keywords: semiconductor quantum well; intersubband excitation; time-resolved photoluminescence; photoluminescence quenching; rate equation model
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
- F-ELBE
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 15610) publication
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Applied Physics Letters 99(2011)4, 041103
DOI: 10.1063/1.3615298
Cited 16 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15610
Hydrogen loss from elastomers subjected to ion irradiation
Jagielski, J.; Grambole, D.; Jozwik, I.; Bielinski, D. M.; Ostaszewska, U.; Pieczynska, D.
Abstract
Hydrogen release from various elastomers upon irradiation with H+, He+ and Ar+ ions has been studied using nuclear reaction analysis (NRA) method. A massive loss of hydrogen atoms upon irradiation has been noted, the results point to the saturation of hydrogen content at about 10 at.%. The analysis of the experimental data indicates that the hydrogen release is controlled by inelastic collisions between ions and target electrons.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15608) publication
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Materials Chemistry and Physics 127(2011)1-2, 342-346
DOI: 10.1016/j.matchemphys.2011.02.015
Cited 16 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15608
Visualization of the focus in congenital hyperinsulinism by intraoperative sonography
von Rohden, L.; Mohnike, K.; Mau, H.; Eberhard, T.; Mohnike, W.; Blankenstein, O.; Empting, S.; Koch, M.; Fuechtner, F.; Barthlen, W.
Abstract
In surgery for focal congenital hyperinsulinism (CHI), the identification and complete resection of the focus without collateral damage is of utmost importance. In a pilot study we applied intra-abdominal high-frequency sonography during surgery for focal CHI in 2 infants. The focus could be identified, its relation to the pancreatic and common bile duct could be shown, and the typical octopus-like tentacles could be demonstrated. In one case the resection was successful; in the other it was not. These preliminary results suggest that intraoperative sonography could be a valuable tool in the surgical therapy of focal CHI and warrants further evaluation in a clinical study.
Keywords: Intraoperative sonography; Congenital hyperinsulinism; Pancreatic resection
Involved research facilities
- PET-Center
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Seminars in Pediatric Surgery 20(2011)1, 28-31
DOI: 10.1053/j.sempedsurg.2010.10.011
ISSN: 1055-8586
Cited 12 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15606
Brouwer’s problem on a heavy particle in a rotating vessel: wave propagation, ion traps, and rotor dynamics
Kirillov, O. N.
Abstract
In 1918 Brouwer considered stability of a heavy particle in a rotating vessel. This was the first demonstration of a rotating saddle trap which is a mechanical analogue for quadrupole particle traps of Penning and Paul. We revisit this pioneering work in order to uncover its intriguing connections with classical rotor dynamics and fluid dynamics, stability theory of Hamiltonian and non-conservative systems as well as with the modern works on crystal optics and atomic physics. In particular, we find that the boundary of the stability domain of the undamped Brouwers problem possesses the Swallowtail singularity corresponding to the quadruple zero eigenvalue. In the presence of dissipative and non-conservative positional forces there is a couple of Whitney umbrellas on the boundary of the asymptotic stability domain. The handles of the umbrellas form a set where all eigenvalues of the system are pure imaginary despite the presence of dissipative and non-conservative positional forces.
Keywords: Rotating saddle; Dissipation-induced instabilities; Merkin theorem; Swallowtail; Whitney umbrella; Exceptional point
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Physics Letters A 375(2011)15, 1653-1660
DOI: 10.1016/j.physleta.2011.02.056
Cited 17 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15605
Array anisotropy in structured thin film arrays: Influence on the magnetodynamics
Wolf, M.; Patschureck, C.; Schafer, R.; Monch, I.; Schultz, L.; McCord, J.
Abstract
The dynamic magnetic properties of soft-ferromagnetic thin film element arrays are strongly influenced by long range interelement magnetostatic interaction. In order to estimate the effective array dipolar field a quantitative model is presented, which is based on the superposition of stray fields that arise from the neighborhood of a reference element. Kittel's equation, that describes the magnetodynamics, is generalized for magnetically saturated arrays by additional array dipolar field terms. Measurements of the magnetodynamic response of quasi-saturated arrays with a rectangular base agree with theoretical predictions. Thus, our model allows the estimation of the frequency of the uniform precessional mode in mesoscopic thin film arrays with non-negligible magnetostatic interaction.
Keywords: magnetization dynamics
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Journal of Magnetism and Magnetic Materials 323(2011), 1703-1707
DOI: 10.1016/j.jmmm.2010.12.048
ISSN: 0304-8853
Cited 6 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15604
Exceptional Points in a Microwave Billiard with Time-Reversal Invariance Violation
Dietz, B.; Harney, H. L.; Kirillov, O. N.; Miski-Oglu, M.; Richter, A.; Schaefer, F.
Abstract
We report on the experimental study of an exceptional point (EP) in a dissipative microwave billiard with induced time-reversal invariance (T) violation. The associated two-state Hamiltonian is non-Hermitian and nonsymmetric. It is determined experimentally on a narrow grid in a parameter plane around the EP. At the EP the size of T violation is given by the relative phase of the eigenvector components. The eigenvectors are adiabatically transported around the EP, whereupon they gather geometric phases and in addition geometric amplitudes different from unity.
Keywords: Microwave billiard; time-reversal symmetry; non-Hermitian hamiltonian; geometric phase; exceptional point; geometric amplitude; geometric pumping
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Physical Review Letters 106(2011)15, 150403
DOI: 10.1103/PhysRevLett.106.150403
Cited 96 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15603
TRLFS study on the speciation of uranium in seepage water and pore water of heavy metal contaminated soil
Baumann, N.; Arnold, T.; Lonschinski, M.
Abstract
In situ leaching of uranium ores with sulfuric acid during active uranium mining activity on the Gessenheap has caused longstanding environmental problems of acid mine drainage and elevated concentrations of uranium. To study there remediation measures the test site Gessenwiese, a recultivated former uranium mining heap near Ronnenburg/East Thuringia/Germany, was installed as a part of a research program of the Friedrich Schiller University Jena to study, amongs other techniques, the phytoremediation capacity of native and selected plants towards uranium. In a first step the uranium speciation in surface seepage and soil pore waters from the Gessenwiese, ranging in pH from 3.2 to 4.0, were studied by Time-resolved Laser-induced Fluorescence Spectroscopy (TRLFS). Both types of water samples showed a mono-exponential fluorescene decay, indicating the presence of only one major species. The detected emission bands were found at 477, 491, 513, 537, 562, and 591 nm (478 – 492 – 513 – 538 – 562 – 590). These characteristic peak maxima together with the observed mono-exponential decay revealed indicated that the uranium speciation in the seepage and soil pore waters is dominated by the uranium (VI) sulfate species UO2SO4(aq). Due to the presence of fluorescence quenchers in the natural water samples the measured fluorescence lifetimes of the UO2SO4(aq) species of 1.0 to 2.6 µs were reduced in comparison to pure uranium sulphate solutions, which show a fluorescence lifetime of 4.7µs.
This results convincingly show that in the pH range of 3.2 to 4.0 TRLFS is a suitable and very useful technique to study the uranium speciation in naturally occurring water samples.
Keywords: Time-resolved laser-induced fluorescence spectroscopy; TRLFS; Uranium(VI); Speciation; Pore water; Seepage water
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Journal of Radioanalytical and Nuclear Chemistry 291(2012)3, 673-679
DOI: 10.1007/s10967-011-1389-z
Cited 8 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15602
Traveling-wave Thomson scattering: a source of X-ray photons with high per-shot yield and tunable energy and bandwidth
Debus, A.; Bussmann, M.; Siebold, M.; Jochmann, A.; Irman, A.; Schramm, U.; Cowan, T. E.; Sauerbrey, R.
Abstract
Thomson sources, driven by laser-wakefield accelerated (LWFA) electrons or small linacs are compact in size and can provide ultrashort, hard X-ray pulses of high brilliance [1]. However, in head-on (180°) Thomson setups, the finite Rayleigh length at small interaction diameters ultimately prevents further advances in peak brilliance, since it becomes increasingly difficult to avoid the nonlinear Thomson regime.
Effectively, not the laser or electron properties, but the interaction geometry limits the performance of all future Thomson sources that aim for high single-shot photon yields.
In order to circumvent this bottleneck, we present a novel concept, which allows obtaining centimeter to meter long optical undulators, where interaction length and diameter are independent of each other.
With an ultrashort, high-power laser pulse in an oblique angle scattering geometry using tilted pulse fronts, electrons and laser remain overlapped while both beams travel over distances much longer than the Rayleigh length.
Such a Traveling-wave Thomson scattering (TWTS) design [2] is particularly interesting for future LWFA-driven Thomson sources with photon yields per pulse that can be orders of magnitudes beyond current designs. In addition, TWTS offeres unique advantages with respect to the minimum scattered bandwidth, which here is independent of the ultrashort laser pulse duration. Instead, it is controlled by the width of a cylindrically focused laser beam.
The possibility to freely choose a side-scattering angle -- from 0 to over 120° -- enables tuning of the photon energy without having to change the electron energy. For optimized LWFA electron sources operating within a narrow energy range, this opens up access to large parts of the X-ray spectrum and hence many applications.
Towards experimental realization, we show how a Traveling-wave setup has to be implemented. An emphasis is put on the use of varied-line spacing (VLS) gratings for dispersion precompensation of the laser beam at large interaction angles to achieve the required overlap between laser and electrons within the interaction region.
[1] A. D. Debus et al., Linear and non-linear Thomson-scattering x-ray sources driven by conventionally and laser plasma accelerated electrons, Proc. SPIE, Vol. 7359, 735908, 2009
[2] A. D. Debus et al., Traveling-wave Thomson scattering and optical undulators for high-yield EUV and X-ray sources, Applied Physics B: Lasers and Optics 100(1), 61-76, 2010
Keywords: Traveling-wave Thomson scattering; X-ray; VLS gratings
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Lecture (Conference)
Optics + Optoelectronics 2011 Harnessing Relativistic Plasma Waves as Novel Radiation Sources from Terahertz to X-rays and Beyond, 18.-21.04.2011, Prag, Tschechische Republik
Permalink: https://www.hzdr.de/publications/Publ-15601
Coupled neutronic thermo-hydraulic analysis of full PWR core with Monte-Carlo based BGCore system
Kotlyar, D.; Shaposhnik, Y.; Fridman, E.; Shwageraus, E.
Abstract
BGCore reactor analysis system was recently developed at Ben-Gurion University for calculating in-core fuel composition and spent fuel emissions following discharge. It couples the Monte Carlo transport code MCNP with an independently developed burnup and decay module SARAF. Most of the existing MCNP based depletion codes (e.g. MOCUP, Monteburns, MCODE) tally directly the one-group fluxes and reaction rates in order to prepare one-group cross sections necessary for the fuel depletion analysis. BGCore, on the other hand, uses a multi-group (MG) approach for generation of one group cross-sections. This coupling approach significantly reduces the code execution time without compromising the accuracy of the results.
Substantial reduction in the BGCore code execution time allows consideration of problems with much higher degree of complexity, such as introduction of thermal hydraulic (TH) feedback into the calculation scheme. Recently, a simplified TH feedback module, THERMO, was developed and integrated into the BGCore system. To demonstrate the capabilities of the upgraded BGCore system, a coupled neutronic TH analysis of a full PWR core was performed. The BGCore results were compared with those of the state of the art 3D deterministic nodal diffusion code DYN3D. Very good agreement in major core operational parameters including k-eff eigenvalue, axial and radial power profiles, and temperature distributions between the BGCore and DYN3D results was observed. This agreement confirms the consistency of the implementation of the TH feedback module.
Although the upgraded BGCore system is capable of performing both, depletion and TH analyses, the calculations were performed for the beginning of cycle state with pre-generated fuel compositions.
Keywords: Monte Carlo; DYN3D; PWR; 3D core analysis; Thermal Hydraulic analysis
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Nuclear Engineering and Design 241(2011)9, 3777-3786
DOI: 10.1016/j.nucengdes.2011.07.028
Cited 70 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15600
High Resolution TEM Study of WS2 Nanotubes
Krause, M.; Mücklich, A.; Zak, A.; Seifert, G.; Gemming, S.
Abstract
Closed capped WS2 nanotubes with diameters from 30 to 110 nm are studied by high resolution transmission electron microscopy. The tubes exhibit preferentially a hexagonal stacking order. Atomic resolution images of a 30 nm diameter tube reveal a zigzag chirality. A lattice expansion in c-axis direction of ≤ 11% is found within the outermost triple layers. The tube caps often display regular polygon angles. Structural defects like grain boundaries, non-planar triple layers, dislocations, platelet-like fragments, terraces, and amorphous precipitates are identified.
Keywords: Inorganic Nanotubes; HRTEM; Microstructure; Structural Defects
- Physica Status Solidi (B) 248(2011)11, 2716-2719
Permalink: https://www.hzdr.de/publications/Publ-15599
Time-resolved photoluminescence quenching measurements in InAs/GaAs quantum dots using terahertz laser pulses
Bhattacharyya, J.; Zybell, S.; Wagner, M.; Helm, M.; Hopkinson, M.; Wilson, L. R.; Schneider, H.
Abstract
Carrier dynamics and relaxation processes in self assembled quantum dots (QDs) are of fundamental interest due to their influences on the efficiency and performances of optoelectronic devices [1]. The intersublevel relaxation mechanisms influence the temporal response of the photoluminescence (PL) [2]. It is therefore interesting to study the carrier relaxation in a series of QD samples where the intersublevel separation varies, resulting in different relaxation times. In this paper we present our work on time-resolved PL quenching measurements on QD ensembles using terahertz pulses, to study the effect of carrier redistribution on PL. Interband quasi-resonant excitation was done by a Ti-Sapphire laser and the PL emission was measured using a spectrometer coupled to a streak camera. Terahertz pulses were obtained from a Free Electron Laser (FEL) synchronized to the Ti:Sapphire laser. The FEL wavelengths were tuned to excite intersublevel transitions in the QDs (ranging from 23 meV to 15 meV) which caused partial depletion of the electronic ground state resulting in quenching of the interband PL. The samples studied consisted of a series of self-assembled InAs/GaAs QDs for which the intersublevel relaxation times varied from few ps to ns, as a result of thermal annealing [3]. Simultaneous time and wavelength resolved measurements enabled us to study the carrier redistribution by the terahertz pulse and their dynamics. PL measurements were done with and without FEL pulses. Figure 1 shows the calculated difference of two such streak camera images measured for a typical QD sample. The blue regions show the PL quenching dip caused by the FEL excitation for two interband transition energies corresponding to the QD ensemble. The data was fitted using exponential functions convoluted with a Gaussian system response. From the fitting parameters the PL quenching depth and recovery times were extracted. The recovery times were found to be significantly shorter than the intersublevel relaxation times suggesting that other mechanisms like interdot transfer and multiphoton excitations were also involved. We performed measurements for different FEL excitation powers, which showed an eventual saturation of the PL quenching. We observed an increase in the PL signal for the lower energy transition after the recovery of the PL, as shown by the orange region in Figure 1. However the carrier redistribution was found to depend on the intersublevel properties of the samples. In this work we will present a comparative analysis for different QD samples, with emphasis on the effect of intersublevel relaxation times on the carrier dynamics.
Keywords: photoluminescence quenching; quantum dots; free electron laser
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 15598) publication
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Lecture (Conference)
International Workshop on Optical Terahertz Science and Technology, 13.-17.03.2011, Santa Barbara, USA -
Lecture (Conference)
DPG Frühjahrstagung der Sektion AMOP (SAMOP) und der Sektion Kondensierte Materie (SKM) 2011, 13.-18.03.2011, Dresden, Germany
Permalink: https://www.hzdr.de/publications/Publ-15598
Diameter dependent TEM and Raman study of WS2 nanotubes
Krause, M.; Mücklich, A.; Viršek, M.; Remškar, M.; Zak, A.; Seifert, G.; Gemming, S.
Abstract
Metal dichalcogenide (MX2) nanotubes and particles, commonly classified as inorganic fullerene-like (IF) materials, represent the inorganic counterparts of carbon nanotubes and fullerenes. They are usually constituted of several MS2 triple layers, whose curvature is provided by specific defect sites. WS2 and MoS2 IF's have recently attracted much interest as dry lubricants and grease additives due to friction coefficients lower than those of platelet based standard mineral oil additives.
In this study WS2 nanotubes with diameters in the range of 28 nm to 290 nm are studied by electron microscopy and resonant 1st and 2nd order Raman spectroscopy. The Raman response is compared to that of 2H-WS2 single crystals and microcrystalline 2H-WS2 powder. With decreasing tube diameter a disorder induced line in the A1g range, termed D-A1g line, is increasingly enhanced. For the thinnest tubes it is even stronger than the fundamental A1g crystal mode. The intensity ratio I (D-A1g)/ I (A1g) follows a simple functional relationship. It resembles that of the well known ID/ IG ratio in disordered carbon. The enhancement mechanism of the D-A1g line is discussed in terms of the increasing number of local defects, which is the consequence of the increasing curvature.
[1] M. Krause, M. Viršek, M. Remškar, N. Salacan, N. Fleischer, L. Chen, P. Hatto, A. Kolitsch, W. Möller, "Diameter and Morphology Dependent Raman Signatures of WS2 Nanostructures", ChemPhysChem, 10, 2221-2225 (2009)
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Poster
25th International Winterschool on: Electronic Properties of Novel Materials: “Molecular nanostructures”, 26.02.-04.03.2011, Kirchberg, Österreich
Permalink: https://www.hzdr.de/publications/Publ-15597
Beschleuniger zum Nachweis geringster Isotopenkonzentrationen
Merchel, S.; Akhmadaliev, S.; Rugel, G.
Abstract
Eingeladener Vortrag ohne Abstract
Keywords: accelerator mass spectrometry; AMS; radionuclides
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15595) publication
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Invited lecture (Conferences)
Fachgespräch Strahlungsmesstechnik und Software, 05.-07.10.2011, Gelsenkirchen, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15595
Cosmogenic noble gases of the Gebel Kamil iron meteorite
Ott, U.; Merchel, S.; Folco, L.; D’Orazio, M.
Abstract
Introduction: The Kamil crater in southern Egypt was first identified during a Google Earth survey. A closer inspection during a geophysical expedition in February 2010 not only revealed details of its structure but also identified several thousand iron meteorite specimens with a total weight of ~1.7 tons [1, 2]. The meteorite is classified as an ungrouped Ni-rich ataxite [3]. He, Ne and Ar measurements have been performed on samples from the only regmaglypted 83 kg individual as well as from a piece of the shrapnel produced during the impact [1, 2].
Experimental:We measured two samples each from the individual and the shrapnel, separated by a distance of ~1 cm in each case. Material from in between is being used for accelerator mass spectrometry of long-lived cosmogenic radionuclides. Because of instabilities in the gain of the electron multiplier, the noble gas abundances were not determined by the (standard) peak height method, but rather by isotope dilution. For that, about 1/3 of the sample gas was “spiked” with a gas mixture (3He/4He/22Ne/36Ar ~ 1.2x10-8/1.1x10-6/1.0x10-10/3.8x10-9 cc, Ne and Ar isotopic compositions atmospheric).
Results: As normal for iron meteorites, noble gases are purely spallogenic. Relevant results are listed in Table 1 (concentrations in 10-8 cc/g units; uncertainties in the last digits in parentheses; I = individual, S = shrapnel).
Sample 3He 4He 21Ne 38Ar
I-C 147 (10) 622 (18) 1.59 (4) 9.47 (29)
I-g 138 (9) 604 (20) 1.58 (4) 8.20 (34)
S-C 44 (5) 214 (16) 0.42 (1) 2.39 (10)
S-f 41 (5) 193 (18) 0.35 (1) 2.31 (11)
Discussion: Using the model calculations of [4], we can derive bounds on the pre-atmospheric size of the object and can define a possible range of cosmic ray exposure ages. Most useful is the 4He/38Ar ratio (cf. Fig. 13 in [4]). Based on the maximum ratio of ~90 (S-C), a minimum radius for the meteoroid is ~85 cm. This implies a preatmospheric mass of >20,000 kg, in excellent agreement with the estimate of [1]. Furthermore, the shrapnel samples must originate from further inside the meteoroid than the individual (35-45 cm vs. 15-25 cm). To reach agreement between 4He/38Ar and 4He/21Ne, a sulfur / phosphorus content in the range 0.4-0.8 wt % contributing to 21Ne production is required ([4, 5; cf. Fig. 11 in [4]). Conflicting cosmic ray exposure ages, however, follow from the relation between 4He/38Ar ratio and 38Ar production rate according to [4]. While for the individual an age on the order of 400 to 500 Ma is indicated, estimates for the shrapnel samples are lower in the 200 to 300 Ma range. The discrepancy may be solved by the radionuclide measurements, which are in progress.
References: [1] Folco L. et al. 2010. Science 329:804. [2] Folco L. et al. 2011. Geology 39:179-182. [3] Weisberg M. K. et al. 2010. Meteoritics & Planetary Science 45:1530-1551. [4] Ammon K. et al. 2009. Meteoritics & Planetary Science 44:485-503; in detail at: http://noblegas.unibe.ch/index.php?content=noblegas/data. [5] Ammon K. et al. 2008. Meteoritics & Planetary Science 43:685-699.
Keywords: cosmogenic nuclides; accelerator mass spectrometry; AMS; exposure age
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15594) publication
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Abstract in refereed journal
Meteoritics & Planetary Science 46(2011), 5012 -
Poster
74th Annual Meeting of the Meteoritical Society, 08.-12.08.2011, London, UK
Permalink: https://www.hzdr.de/publications/Publ-15594
Decisive role of oxygen vacancy in ferroelectric versus ferromagnetic Mn-doped BaTiO3 thin films
Shuai, Y.; Zhou, S.; Bürger, D.; Reuther, H.; Skorupa, I.; John, V.; Helm, M.; Schmidt, H.
Abstract
Single-phase perovskite 5 at.% Mn-doped and undoped polycrystalline BaTiO3 thin films have been grown under different oxygen partial pressures by pulsed laser deposition on platinum-coated sapphire substrates. Ferroelectricity is only observed for the Mn-doped and undoped BaTiO3 thin films grown under relatively high oxygen partial pressure. Compared to undoped BaTiO3, Mn-doped BaTiO3 reveals a low leakage current, increased dielectric loss, and a decreased dielectric constant. Ferromagnetism is seen on Mn-doped BaTiO3 thin films prepared under low oxygen partial pressure and is attributed to the formation of bound magnetic polarons (BMPs). This BMP formation is enhanced by oxygen vacancies. The present work confirms a theoretical work from C. Ederer and N. Spaldin on ferroelectric perovskites [Nature Mat. 3, 849 (2004)] which shows that the existence of ferroelectricity is incompatible with the existence of a spontaneous magnetization in Mn-doped BaTiO3 thin films.
Keywords: multiferroic; Mn-BaTiO₃
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Journal of Applied Physics 109(2011), 084105-1-084105-8
DOI: 10.1063/1.3576125
Cited 128 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15593
How plants cope with heavy metals
Viehweger, K.
Abstract
Heavy metals are naturally occurring in the earth‘s crust but anthropogenic and industrial activities have led to drastic environmental pollutions in distinct areas. Plants are able to colonize such sites due to several mechanisms of heavy metal tolerance. Understanding of these pathways enables different fruitful approaches like phytoremediation and biofortification.
Therefore, this review addresses mechanisms of heavy metal tolerance and toxicity in plants possessing a sophisticated network for maintenance of metal homeostasis. Key elements of this are chelation and sequestration which result either in removal of toxic metal from sensitive sites or conduct essential metal to their specific cellular destination. This implies shared pathways which can result in toxic symptoms especially in an excess of metal. These overlaps go on with signal transduction pathways induced by heavy metals which include common elements of other signal cascades. Nevertheless, there are specific reactions some of them will be discussed with special focus on the cellular level.
Keywords: heavy metals; tolerance; toxicity; signaling; sequestration; chelation
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Botanical Studies 55(2014), 35
DOI: 10.1186/1999-3110-55-35
ISSN: 1817-406X
Cited 349 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15592
Flow structures arising from melt stirring by means of modulated rotating magnetic fields
Räbiger, D.; Eckert, S.; Gerbeth, G.; Franke, S.; Czarske, J.
Abstract
Electromagnetic stirring during solidification has been proved to be a striking method for achieving a purposeful alteration of the microstructure of casting ingots, such as grain refinement or the promotion of a transition from a columnar to an equiaxed dendritic groth (CET). However, the imposition of a rotating (RMF) or a travelling magnetic field (TMF) also causes problems like the occurrence of typical segregation pattern or a deflection of the upper free surface. A permanent radial inward (RMF and downward TMF) or outward (upward TMF) flow along the solidification front is responsible for the transport of solute to the axis or the wall of the ingot resulting in typical freckle segregation pattern filled with alloy of eutectic composition. Recent studies have shown, that modulated AC magnetic fields are appropriate to overcome these problems.
We present an experimental study concerning measurements of the flow inside a liquid metal column exposed to a pulsed rotating magnetic field. A novel ultrasound Doppler system was used two measure two-dimensional velocity fields of the secondary flow in the radial-meridional plane. It employs an array of 25 transducer elements allowing a fast electronic traversing with concurrently high spatial and temporal resolution. The measurements revealed transient flow regimes showing distinct inertial oscillations and coherent vortex structures. The results demonstrate that the arising flow structure depends sensitively on the frequency of the RMF pulses.
Keywords: Electromagnetic stirring; ultrasound Doppler velocimetry; modulated magnetic field; liquid metal flow
- Magnetohydrodynamics 48(2012)1, 213-220
Permalink: https://www.hzdr.de/publications/Publ-15591
SP3 solution versus diffusion solution in nodal codes – which improvement can be expected
Merk, B.; Duerigen, S.
Abstract
A detailed analysis of the differences between the diffusion and the SP3 method is given. The analysis is based on one dimensional analytical solutions for the one and two group diffusion and SP3 method. Different cases from a benchmark core configuration are analyzed with the help of the one dimensional analytical solutions. It is shown that only a limited part of the gain achievable due to the use of the SP3 approximation will be seen in nodal calculations.
Keywords: SP3 method; diffusion; transport; analytical solutions
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Contribution to proceedings
International Conference on Transport Theory, 11.-15.09.2011, Portland, USA -
Lecture (Conference)
International Conference on Transport Theory, 11.-15.09.2011, Portland, USA
Permalink: https://www.hzdr.de/publications/Publ-15590
Importance of unified control for a holding groups motives fulfillment
Joehnk, P.; Hodulikova, P.; Snircová, J.
Abstract
The article focuses on forming of holding groups and unified economic control in the frame of them. The globalization of markets leads to a need for bigger and stronger companies. Therefore, we can talk about dramatic increases in the frequency and volume of corporate groups. The most important reason for these combinations is to acquire advantages, which can have economic and noneconomic character. Another important is the limitation or elimination of competitive influences. [1] A holding group as a form of corporate group is a reality, which can go behind the borders of the European Union nowadays. Although, holding groups have been in advanced industrial countries for more than several decades, this type of structure has a relatively brief history in Slovakia. Also the theoretical background of this issue is, in Slovak literature, relatively poor.
Keywords: holding group; synergism; unified control
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Lecture (others)
International Doctoral Seminar, 15.-17.05.2011, Smolenice, Slovak -
Contribution to proceedings
International Doctoral Seminar, 15.-17.05.2011, Smolenice, Slovak
Proceeding, 154-161
Permalink: https://www.hzdr.de/publications/Publ-15589
Study of the 2H(α,γ)6Li reaction at LUNA
Anders, M.; Bemmerer, D.
Abstract
Observations of very metal-poor stars have yielded evidence for the less abundant lithium isotope 6Li in several cases. These findings prompt the question whether there is a non-negligible primordial contribution to the observed 6Li abundances. Network calculations show that the 2H(α,γ)6Li reaction dominates 6Li production in the Big Bang. A recent Coulomb dissociation work on this reaction produced only an upper limit for the astrophysical S-factor. At the 400 kV underground accelerator LUNA in Gran Sasso/Italy, an experiment is underway to gain direct cross section data, but the background is formidable. Preliminary data of the first phase of the LUNA experiment will be shown, and an outlook will be given.
Keywords: LUNA; LNGS; Laboratori Nazionali del Gran Sasso; nucleosynthesis; Big Bang; nuclear astrophysics; lithium; beam induced background
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Lecture (Conference)
DPG-Frühjahrstagung Münster 2011, 22.03.2011, Münster, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15588
Direct measurement d(α,γ)6Li at LUNA
Anders, M.
Abstract
The talk summarizes the first phase of the direct d(alpha,gamma)6Li cross section measurement at energies of astrophysical interest by the LUNA collaboration at Laboratori Nazionali del Gran Sasso. The role of 6Li during primordial nucleosynthesis, the current problems of explaining its abundance in very old stars, the measurement approach, details about the beam induced background and ideas to control it are the main topics.
Keywords: LUNA; LNGS; Laboratori Nazionali del Gran Sasso; nuclear astrophysics; nucleosynthesis; beam induced background
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Lecture (Conference)
8th Russbach Workshop on Nuclear Astrophysics 2011, 13.03.2011, Rußbach am Pass Gschütt, Österreich
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Permalink: https://www.hzdr.de/publications/Publ-15587
Superconducting nanolayers in Ge and Si fabricated by Ga+ ion implantation and rapid thermal annealing
Heera, V.; Fiedler, J.; Skrotzki, R.; Herrmannsdörfer, T.; Voelskow, M.; Mücklich, A.; Schmidt, B.; Skorupa, W.
Abstract
Superconducting nanolayers in Ge and Si can be fabricated by high fluence Ga ion implantation and subsequent rapid thermal annealing.
Keywords: superconducting Ge; superconducting Si; Ga ion implantation; rapid thermal annealing
Involved research facilities
- High Magnetic Field Laboratory (HLD)
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15586) publication
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Lecture (others)
29. Treffen der Nutzergruppe Heißprozesse und RTP, 12.05.2011, Erlangen, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15586
Eukaryotic life in Biofilms formed in a Uranium Mine
Zirnstein, I.; Arnold, T.; Krawczyk-Bärsch, E.; Jenk, U.; Bernhard, G.; Röske, I.
Abstract
The underground uranium mine Königstein (Saxony, Germany), currently in the process of remediation, represents a underground acid mine drainage environment (AMD), i.e. low pH conditions and high concentrations of heavy metals including uranium, in which eye-catching biofilm formations were observed. During active uranium mining from 1967-1990 technical leaching with sulphuric acid was applied underground on-site resulting in a change of the underground mine environment and initiated the formation of AMD and also the growth of AMD-related copious biofilms.
Biofilms grow underground in the mine galleries in a depth of 250 m (50 m above sea level) either as stalactite-like slime communities or as acid streamers in the drainage channels. The eukaryotic diversity of these biofilms was analyzed by microscopic investigations and by molecular methods, i.e. 18S rDNA PCR, cloning and sequencing. The biofilm communities of the Königstein environment showed a low eukaryotic biodiversity and consisted of a variety of groups belonging to nine major taxa: ciliates, flagellates, amoebae, heterolobosea, fungi, apicomplexa, stramenopiles, rotifers and arthropoda and a large number of uncultured eukaryotes, denoted as acidotolerant eukaryotic cluster (AEC). In Königstein the flagellates Bodo saltans, the stramenopiles Diplophrys archeri and the phylum of rotifers, class Bdelloidea were detected for the first time in an AMD environment characterized by high concentrations of uranium. This study shows that not only bacteria and archaea may live in radioactive contaminated environments, but also species of eukaryotes, clearly indicating their potential influence on carbon cycling and metal immobilization within AMD affected environment.
Keywords: eukaryote; uranium; acid mine drainage; biofilm; microbial diversity; acid streamer; 18S rDNA PCR; light microscopy
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MicrobiologyOpen 1(2012)2, 83-94
DOI: 10.1002/mbo3.17
Cited 27 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15585
Cathepsin S inhibitors: WO2010070615
Löser, R.
Abstract
This article evaluates a patent application of the company Medivir (SE/UK) describing the synthesis of dipeptide-derived alpha alpha-ketoamides containing a propylene glycine moiety in P1 as selective inhibitors of cathepsin S for the potential treatment of various systemic human diseases such as several autoimmune diseases, MS, rheumatoid arthritis, endometriasis and chronic pain. The claims of the patent are discussed in light of recent results in the field of cathepsin S research.
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Expert Opinion on Therapeutic Patents 21(2011)4, 585-591
DOI: 10.1517/13543776.2011.550574
ISSN: 1354-3776
Cited 3 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15584
Application of a new drag coefficient model at CFD-simulations on free surface flows relevant for the nuclear reactor safety analysis
Deendarlianto; Höhne, T.; Apanasevich, P.; Lucas, D.; Vallée, C.; Beyer, M.
Abstract
This paper presents different CFD-simulations on flows which are relevant for nuclear reactor safety using a new modelling approach for the interfacial drag at free surfaces. The developed drag coefficient model was implemented together with the Algebraic Interfacial Area Density (AIAD) model (Höhne, 2009) into the three-dimensional (3-D) computational fluid dynamics (CFD) code ANSYS-CFX. The applications considered include the prediction of counter-current flow limitations (CCFL) in a PWR hot leg, the development of hydraulic jump during the air-water co-current flow in a horizontal channel, and pressurized thermal shock (PTS) phenomena in a PWR cold leg and downcomer. For the modelling of these tasks, an Euler–Euler approach was used. This approach allows the use of different models depending on the local morphology. In the frame of an Euler-Euler simulation, the local morphology of the phases has to be considered in the drag model.
To demonstrate the feasibility of the present approach, the computed main parameters of each case were compared with experimental data. It is shown that the CFD calculations agree well with the experimental data. This indicates that the AIAD model combined with new drag force modeling is a promising way to simulate the phenomena in frame of the Euler-Euler approach. Moreover the further validation of the model by including mass transfer effects should be carried out.
Keywords: Computational fluid dynamics (CFD); Algebraic interfacial area density (AIAD) model; Drag coefficient; Pressurized water reactor (PWR); Hot leg; Cold leg; Counter-current flow limitation (CCFL); Hydraulic jump; Slug flow; Stratified flow; Pressurized thermal shocks (PTS); Downcomer
Involved research facilities
- TOPFLOW Facility
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Annals of Nuclear Energy 39(2012), 70-82
DOI: 10.1016/j.anucene.2011.09.010
Cited 21 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15583
Scanning near-field infrared microspectroscopy on semiconductor structures
Jacob, R.
Abstract
Near-field optical microscopy has attracted remarkable attention, as it is the only technique that allows the investigation of local optical properties with a resolution far below the diffraction limit. Especially, the scattering-type near-field optical microscopy allows the nondestructive examination of surfaces without restrictions to the applicable wavelengths. However, its usability is limited by the availability of appropriate light sources. In the context of this work, this limit was overcome by the development of a scattering-type near-field microscope that uses a widely tunable free-electron laser as primary light source.
In the theoretical part, it is shown that an optical near-field contrast can be expected when materials with different dielectric functions are combined. It is derived that these differences yield different scattering cross-sections for the coupled system of the probe and the sample. Those cross-sections define the strength of the near-field signal that can be measured for different materials. Hence, an optical contrast can be expected, when different scattering cross-sections are probed. This principle also applies to vertically stacked or even buried materials, as shown in this thesis experimentally for two sample systems.
In the first example, the different dielectric functions were obtained by locally changing the carrier concentration in silicon by the implantation of boron. It is shown that the concentration of free charge-carriers can be deduced from the near-field contrast between implanted and pure silicon. For this purpose, two different experimental approaches were used, a non-interferometric one by using variable wavelengths and an interferometric one with a fixed wavelength. As those techniques yield complementary information, they can be used to quantitatively determine the effective carrier concentration. Both approaches yield consistent results for the carrier concentration, which excellently agrees with predictions from literature. While the structures of the first system were in the micrometer regime, the capability to probe buried nanostructures is demonstrated at a sample of indium arsenide quantum dots. Those dots are covered by a thick layer of gallium arsenide. For the first time ever, it is shown experimentally that transitions between electron states in single quantum dots can be investigated by near-field microscopy. By monitoring the near-field response of these quantum dots while scanning the wavelength of the incident light beam, it was possible to obtain characteristic near-field signatures of single dots. Near-field contrasts up to 30 % could be measured for resonant excitation of electrons in the conduction band of the indium arsenide dots.
Keywords: Spectroscopy; Near-field microscopy; Infrared; Semiconductor materials; quantum dots
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 15582) publication
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Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-009 2011
ISSN: 2191-8708, eISSN: 2191-8716
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Permalink: https://www.hzdr.de/publications/Publ-15582
Miniaturisierte BeO-OSL-Detektoren für die Dosimetrie in Zellkulturen und Organismen: Anwendung und Herausforderungen
Anders, M.
Abstract
Dosimetrie in Organismen oder in Zellkulturen erfordert Detektoren mit einer angepassten Größe, die zugleich chemisch und biologisch völlig inert sind. In Rahmen der an der Technischen Universität Dresden angefertigten Diplomarbeit wurden miniaturisierte Detektoren aus gesintertem Berylliumoxid mit positivem Ergebnis auf ihre Anwendbarkeit in der OSL-Dosimetrie und der Biotechnologie untersucht. Die Dosischarakteristik, die typische Messabweichung und die untere Erkennungsgrenze wurden bestimmt. Die Ergebnisse werden in Zusammenhang zur Theorie der Dosimetrie und der Wechselwirkungen der Strahlungsfelder gebracht. In Zusammenarbeit mit der Karlsruhe Beryllium Handling Facility wurde eine weitere Miniaturisierung der Detektoren erreicht, die aber mit einer erhöhten Erkennungsgrenze und einer zunehmend schwierigen Handhabung verbunden ist.
Keywords: BeO; Berylliumoxid; Dosimetrie; Optisch stimulierte Lumineszenz; OSL
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Lecture (others)
Institutsseminar des Instituts für Kern- und Teilchenphysik, Technische Universität Dresden, 22.07.2010, Dresden, Deutschland
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Permalink: https://www.hzdr.de/publications/Publ-15581
Towards an understanding of the Von-Karman-Sodium dynamo experiment
Giesecke, A.; Gerbeth, G.; Stefani, F.
Abstract
Numerical simulations of kinematic dynamo action have been carried out in a setup that resembles the configuration of the Von-Karman-Sodium (VKS) dynamo experiment. The results show that the high permeability domains introduced by soft iron impellers essentially determine the field generation process and are also responsible for the selection of the dominating azimuthal dynamo mode.
The material heterogeneity within the fluid give rise to three distinct effects that may influence the dynamo process. In addition to the local decrease of the magnetic diffusivity eta=(mu_0\mu_r\sigma)(-1) so called paramagnetic pumping occurs which is proportional to the gradient of the permeability and describes the suction of magnetic field into domains with high permeability. Beside the modifications of the induction equation itself, jump conditions of the magnetic field (respectively the electric field) are enforced on the material interfaces between fluid and impellers. These jump conditions and the pumping term are responsible for the distinct behavior of high conducting(i.g. copper) and soft iron impellers.
At reasonable values for the magnetic Reynolds number (i.e around Rm=30) and rather moderate permeability (around values of 60 as suggested from recent measurements) the simulated magnetic field is dominated by an axisymmetric component. However, to obtain a growing axisymmetric eigenmode still an alpha-effect is necessary that parametrizes the induction effects of helical small scale motions. In contrast to preliminary mean field models for the VKS dynamo that have been based solely on an alpha-omega mechanism, the necessary magnitude for the alpha effect remains reasonable small if soft iron impellers are utilized.
Keywords: Dynamo; VKS; Numerical Simulations; Magnetohydrodynamics; Permeability
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Poster
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo – Corsica, France -
Contribution to proceedings
8th PAMIR International Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo – Corsica, France
Towards an understanding of the Von-Karman-Sodium dynamo experiment
Permalink: https://www.hzdr.de/publications/Publ-15580
The LUNA experiment at the Gran Sasso Laboratory in Italy
Anders, M.
Abstract
The LUNA experiment is dedicated to measure low energy cross sections of reactions of astrophysical interest. Motivating these measurements with the question about the origin and the different abundances of isotopes in our universe, the reason to perform them in a deep underground laboratory is also mentioned. Using the example of the 2H(alpha, gamma)6Li reaction, the measurement approach and the apparatus are introduced.
Keywords: LUNA; LNGS; Laboratori Nazionali del Gran Sasso; low background; nuclear astrophysics
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Lecture (Conference)
Gran Sasso-South Dakota-Princeton Physics Summer School - 2010, 13.07.2010, Laboratori Nazionali del Gran Sasso, Italia
Permalink: https://www.hzdr.de/publications/Publ-15579
Resonanzstärken in der 40Ca(alpha,gamma)44Ti-Reaktion
Schmidt, K.; Akhmadaliev, C.; Anders, M.; Bemmerer, D.; Boretzky, K.; Caciolli, A.; Elekes, Z.; Fülöp, Z.; Gyürky, G.; Hannaske, R.; Junghans, A.; Marta, M.; Schwengner, R.; Szücs, T.; Wagner, A.; Zuber, K.
Abstract
Das Nuklid 44Ti (Halbwertszeit 59 Jahre) wird in Supernovae erzeugt. Die Gamma-Strahlung aus seinem Zerfall lässt sich in weltraumgestützten Gamma-Teleskopen nachweisen und kann als Werkzeug zum Test von Supernova-Modellen genutzt werden. Hierfür ist eine genaue Kenntnis der Kernreaktionsraten für die Erzeugung und Zerstörung von 44Ti erforderlich. Die 40Ca(alpha,gamma)44Ti-Reaktion dominiert die Erzeugung von 44Ti. Ihre Rate wird von einer Vielzahl von Resonanzen bestimmt. Um präzise Daten zu gewinnen, wurde die Stärke des Resonanztripletts bei 4.5MeV Gamma-Energie am Dresdner 3MV Tandetron sowohl mittels in-beam Gamma-Spektrometrie als auch durch eine Aktivierungsmessung im Felsenkeller-Niederniveaumesslabor gemessen. Eine Untersuchung der bestrahlten Proben mittels Beschleunigermassenspektrometrie ist geplant. – Gefördert von der EU (FP7-SPIRIT 227012) und der DFG (BE 4100/2-1).
Keywords: 44Ti; Supernova; 40Ca(alpha,gamma)44Ti; 3MV Tandetron; Felsenkeller
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15578) publication
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Lecture (Conference)
DPG Frühjahrstagung Münster 2011, 21.-25.03.2011, Münster, Deutschland -
Lecture (others)
Institutsseminar (Kolloquium)am Institut für Kern- und Teilchenphysik, TU Dresden, 28.04.2010, Dresden, Deutschland -
Lecture (Conference)
2nd workshop on Exotic Radionuclides from Accelerator Waste for Science and Technology (ERAWAST II), 02.09.2011, Paul Scherrer Institute, Switzerland -
Lecture (Conference)
496. Wilhelm und Else Heraeus-Seminar - Astrophysics with modern small-scale accelerators, 05.-10.02.2012, Bad Honnef, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15578
Aus alt mach neu – wie Bakterien beim Recycling von Handys & Co helfen können
Raff, J.
Abstract
Eine der größten Herausforderungen der Gegenwart ist der verantwortungsvolle Umgang mit den Ressourcen unseres Planeten. In diesem Zusammenhang ist die Entwicklung neuartiger Verfahren zur Gewinnung und vor allem Rückgewinnung von seltenen Metallen aus Industrieprodukten als wichtige Rohstoffe zahlreicher Zukunftstechnologien von besonderer Relevanz.
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 15577) publication
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Invited lecture (Conferences)
Tage der Wissenschaften, 06.07.2011, Radebeul, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-15577
Cu-61 production with increased SA
Thieme, S.
Abstract
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Lecture (others)
Seminarvortrag, Turku PET Centre, 31.03.2011, Turku, Finland
Permalink: https://www.hzdr.de/publications/Publ-15576
Radiopharmazeutische Werkzeuge zur molekularen Bildgebung und Therapie von Tumoren
Thieme, S.
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Lecture (others)
Wissenschaftstage der Hochschule Lausitz, 26.11.2009, Senftenberg, D
Permalink: https://www.hzdr.de/publications/Publ-15575
Adenosine is released per se under physiological conditions from the rat striatum in vivo
Pedata, F.; Melani, A.; Corti, F.; Stephan, H.; Müller, C. E.; Vannucchi, M. G.
Abstract
In this study, extracellular concentrations of adenosine and ATP from the rat striatum were estimated by the microdialysis technique under physiological conditions and during focal cerebral ischemia induced by middle cerebral artery occlusion (MCAo). Under these conditions, adenosine and ATP concentrations were in the range of 130 nM and 30 nM, respectively. Blocking the ecto-ATPases with the novel inhibitor polyanion [TiW11CoO40]8- (PV4: 100 μM), recently synthesized and characterized by Stephan and Müller, we could demonstrate that the extracellular concentration of ATP increased 12-fold and that adenosine concentration was not modified. This result indicates that, under physiological conditions, adenosine is released per se from cells. In the presence of PV4 and of the adenosine equilibrative transporter inhibitor dipyridamole (100 μM), adenosine extracellular concentration was increased 3-fold. This result excludes the possibility that adenosine is carried out of cells by a carrier mediated efflux. By using immunolabeling and electron microscopy, we showed the presence of the CNT2 on plasma membrane of synaptic terminals and on vesicle membranes. Results suggest that under in vivo physiological conditions adenosine is transported in vesicles and is released in an excitation-secretion manner.
In the first 4 hours after in vivo ischemia induced by MCAo, adenosine increased to ~690 nM and ATP to ~50 nM. In the presence of PV4 the extracellular concentration of ATP increased to ~440 nM and extracellular adenosine decreased to ~270 nM. An upregualtion of ecto-nucleotidases after ischemia might represent an important mechanism in hydrolysis of ATP and formation of extracellular adenosine in the first hours after ischemia.
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Lecture (Conference)
International Conference on Purinergic Drugs and Targets 2011, 22.-25.07.2011, Bonn, D -
Abstract in refereed journal
Purinergic Signalling 8(2012)1, 132
ISSN: 1573-9538
Permalink: https://www.hzdr.de/publications/Publ-15574
Modes of the use of high intensity plasma beams for ceramic surface modification
Barlak, M.; Piekoszewski, J.; Werner, Z.; Sartowska, B.; Pisarek, M.; Walis, L.; Starosta, W.; Kolitsch, A.; Gröetzchel, R.; Pochrybniak, K.; Bochenska, C.
Abstract
Wetting properties of ceramic materials may be enhanced by treating them with high-intensity plasma pulses carrying a substantial fraction of metallic ions. Rod Plasma Injectors (RPI), developed originally for fusion studies, may generate such plasma pulses containing the working gas used for discharge initiation and the metal ions eroded from the discharge electrodes. We examined the plasma pulse technology and concluded that it is possible to extend the range of system parameters appropriate for wetting enhancement. We also studied the physical properties of plasma treated carbon and silicon carbide samples in an attempt to disclose the origin of wettability differences between them. We finally conclude that these differences are due to the morphology of the treated surfaces.
Keywords: wettability; high intensity pulsed plasma beams; ceramic
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 15573) publication
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Surface & Coatings Technology 206(2011)5, 916-919
DOI: 10.1016/j.surfcoat.2011.04.028
Cited 2 times in Scopus -
Lecture (Conference)
SMMIB 2009, 13.-18.09.2009, Tokyo, Japan
Permalink: https://www.hzdr.de/publications/Publ-15573
Radiopharmaka: Herstellung, Charakterisierung und Anwendungsmöglichkeiten
Stephan, H.
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Invited lecture (Conferences)
Kolloquium Hochschule Zittau/Görlitz, 20.04.2011, Zittau, D
Permalink: https://www.hzdr.de/publications/Publ-15572
Nanoclusters in bcc-Fe containing vacancies, copper and nickel: Structure and energetics
Al-Motasem, A. T.; Posselt, M.; Bergner, F.
Abstract
The most stable atomic configuration of coherent nanoclusters in bcc-Fe formed by vacancies, Cu and Ni as well as the corresponding energetics are determined by on-lattice simulated annealing and subsequent off-lattice relaxation. Ternary v_l Cu_m Ni_n clusters show a core-shell structure with vacancies in the core coated by a shell of Cu atoms, followed by a shell of Ni atoms. In binary Cu_m Ni_n clusters the Cu core is covered by a shell of Ni atoms. On the contrary, binary v_l Ni_n clusters consist of a pure vacancy cluster surrounded by an agglomeration of Ni atoms. The latter is similar to a pure Ni cluster (Ni_n) and consists of Ni atoms at the second nearest neighbor distance. In all clusters investigated Ni atoms may be nearest neighbors of Cu atoms but never nearest neighbors of vacancies or other Ni atoms. The structure obtained for Cu_m Ni_n clusters is in agreement with previous theoretical results and with indications from measurements while for the other clusters reference data are not available. It is shown that the presence of Ni atoms promotes the nucleation of clusters containing vacancies and Cu. This is in agreement with experimental observations and recent theoretical results Compact and rather accurate analytical formulae for the total binding energy have been derived from the results of the atomistic simulations. These relations can be used in rate theory or object kinetic Monte Carlo simulations of nanocluster evolution.
Keywords: Fe-Cu-Ni alloy; Nanostructures; Defects; Monte Carlo simulation; Molecular dynamics simulations
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Journal of Nuclear Materials 418(2011), 215-222
DOI: 10.1016/j.jnucmat.2011.07.002
Cited 26 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15570
Influence of the developing magnetic order on the transport properties of epitaxial Zn1-xCoxO films
Ye, S.; Ney, V.; Kammermeier, T.; Ollefs, K.; Zhou, S.; Schmidt, H.; Ney, A.
Abstract
A series of high quality Zn1-xCoxO films prepared by reactive magnetron sputtering displays altered magnetic properties ranging from paramagnetic (PM) to ferromagnetic (FM)- like at room temperature. With tuning the properties of the Zn1-xCoxO films from PM- to FMlike, the temperature dependent resistivity of the films changes from a Mott variable-range hopping to an Efros variable-range hopping process. This indicates the emergence of a Coulomb gap, which can be explained by the presence of nanoclusters. Moreover, the anhysteretic M (H)-curves above the blocking temperature for superparamagnetic (SPM) films can be described by a Langevin function, which confirms the existence of FM nanoclusters. The investigation on the magneto-transport of these films shows no spin-dependent transport behaviour associated with the observed FM-like/SPM properties.
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Journal of Physics: Conference Series 200(2010), 052034
DOI: 10.1088/1742-6596/200/5/052034
Cited 5 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-15569
The 14N(p,gamma)15O reaction studied with a composite germanium detector
Marta, M.; Formicola, A.; Bemmerer, D.; Broggini, C.; Caciolli, A.; Corvisiero, P.; Costantini, H.; Elekes, Z.; Fulop, Z.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyurky, G.; Imbriani, G.; Junker, M.; Lemut, A.; Limata, B.; Mazzocchi, C.; Menegazzo, R.; Prati, P.; Roca, V.; Rolfs, C.; Rossi Alvarez, C.; Somorjai, E.; Straniero, O.; Strieder, F.; Terrasi, F.; Trautvetter, H. P.; Vomiero, A.
Abstract
The rate of the carbon-nitrogen-oxygen (CNO) cycle of hydrogen burning is controlled by the 14N(p,gamma)15O reaction. The reaction proceeds by capture to the ground states and several excited states in O-15. In order to obtain a reliable extrapolation of the excitation curve to astrophysical energy, fits in the R-matrix framework are needed. In an energy range that sensitively tests such fits, new cross section data are reported here for the four major transitions in the 14N(p,gamma)15O reaction. The experiment has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator placed deep underground in the Gran Sasso facility in Italy. Using a composite germanium detector, summing corrections have been considerably reduced with respect to previous studies. The cross sections for capture to the ground state and to the 5181, 6172, and 6792 keV excited states in O-15 have been determined at 359, 380, and 399 keV beam energy. In addition, the branching ratios for the decay of the 278 keV resonance have been remeasured.
Keywords: Nuclear astrophysics; LUNA; CNO cycle; Sun; solar fusion
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Physical Review C 83(2011), 045804
DOI: 10.1103/PhysRevC.83.045804
Cited 45 times in Scopus -
Contribution to WWW
arXiv server: http://arxiv.org/abs/1103.5393
Permalink: https://www.hzdr.de/publications/Publ-15568
Coupling of the CFD code ANSYS CFX with the 3D neutron kinetic core model DYN3D for VVER applications
Kliem, S.; Grahn, A.; Rohde, U.; Schütze, J.; Frank, T.
Abstract
The CFD code ANSYS CFX has been coupled with the neutron-kinetic core model DYN3D. ANSYS CFX calculates the fluid dynamics and related transport phenomena in the reactor’s coolant and provides the corresponding data to DYN3D. In the fluid flow simulation of the coolant, the core itself is modeled within the porous body approach. DYN3D calculates the neutron kinetics and the fuel behavior including the heat transfer to the coolant. The physical data interface between the codes is the volumetric heat release rate into the coolant. In the prototype that is currently available, the coupling is restricted to single-phase flow problems. In the time domain an explicit coupling of the codes has been implemented so far.
Steady-state and transient verification calculations for a small-size test problem confirm the correctness of the implementation of the prototype coupling. The test problem was a mini-core consisting of seven real-size VVER-1000 fuel assemblies. Comparison was performed with the DYN3D stand-alone code. In the steady state, the effective multiplication factor obtained by the DYN3D/ANSYS CFX codes shows a deviation of 0.2 pcm from the DYN3D stand-alone solution. The transient test case simulated the withdrawal of the control rod from the central fuel assembly at hot zero power in the same mini-core. Power increase during the introduction of positive reactivity and power reduction due to fuel temperature increase are calculated in the same manner by the coupled and the stand-alone codes. The maximum values reached during the power rise differ by about 3 MW at a power level of 240 MW. These differences are caused by the use of different flow solvers.
After this verification a steady-state full power calculation for a full VVER-1000 reactor was carried out in order to show the applicability of the new code system to real problems. A CFX grid consisting of about 1.3 106 nodes was created. The main difference to a pure DYN3D calculation with its 1D thermal hydraulic model is the presence of a lateral coolant flow at a velocity in the order of 1 cm/s from the circumference of the core centre. It is driven by the acceleration of the liquid in the centre due to the stronger heating. This flow increases the exchange of heat in the lateral direction by advection and leads to a ‘smearing’ of the step-like temperature profile that has been found in a pure DYN3D calculation.
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Contribution to proceedings
7th International Conference “Safety Assurance of NPP with VVER”, 17.-20.05.2011, Podolsk, Russland
Proceedings of the 7th International Conference “Safety Assurance of NPP with VVER” paper 007, Podolsk: Gidropress -
Lecture (Conference)
7th International Conference “Safety Assurance of NPP with VVER”, 17.-20.05.2011, Podolsk, Russland
Permalink: https://www.hzdr.de/publications/Publ-15567
Environment Controlled De-wetting Kinetics of Rh-Pd Bilayer Thin Films
Abrasonis, G.; Wintz, S.; Liedke, M. O.; Aksoy, F.; Liu, Z.; Kuepper, K.; Krause, M.; Gemming, S.
Abstract
The control of morphology and surface composition of nanoalloys is the key factor in order to tune or to extend the range of their optical, magnetic and chemical properties. Therefore it is one of the major tasks in nanoalloy materials science. The de-wetting dynamics and kinetics dependence of a Rh-Pd bilayer/alloy thin film model system on chemical environment (CO and NO) is investigated in-situ by means of high pressure x-ray photoelectron spectroscopy. Independently of the initial state, the film surface shows an enrichment of Pd upon heating in vacuum. De-wetting caused by heating in NO or CO shows significant differences in the surface chemical composition evolution and, consequently, in the de-wetting onset temperature. Alternating exposure to NO or CO results in the surface enrichment with either Rh or Pd, respectively, and subsequent film rupture. The results are discussed on the basis of the interplay between thermodynamic and kinetic factors. The study demonstrates the effect of the chemical environment on the morphology as well as on the composition of supported nanostructures.
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Lecture (Conference)
DPG Spring Meeting 2011, 13.-18.03.2011, Dresden, Germany
Permalink: https://www.hzdr.de/publications/Publ-15566
P0714 - Verfahren und Anordnung zur Messung des Durchflusses elektrisch leitfähiger Medien
Gerbeth, G.; Priede, J.; Buchenau, D.
Abstract
Die Erfindung betrifft ein Verfahren und eine Anordnung zur kontaktlosen Messung des Durchflusses elektrisch leitfähiger Medien durch Strömungskanäle. Durch die Erfindung soll eine Durchflussmessung ohne mechanischen oder elektrischen Kontakt zum fließenden Medium zu ermöglicht werden, ohne die zu messende Strömung zu beeinflussen und die unabhängig von möglichen Temperaturänderungen des fließenden Mediums eine direkte Durchflussmessung erlaubt. Erreicht wird das durch Ausbilden eines am Strömungskanal drehbaren einfach polarisierten Magnetfeldes eines Magneten (4), derart, dass die Strömung im Strömungskanal (1) ein Drehmoment auf das Magnetfeld der Magneten (4) ausübt, das proportional zum Produkt aus der elektrischen Leitfähigkeit des strömenden Mediums und dessen mittleren Geschwindigkeit ist und das den Magneten (4) in Drehung versetzt, derart, dass ein Drehmoment auf das strömende Medium im Strömungskanal (1) ausgeübt wird, welches proportional zur elektrischen Leitfähigkeit des strömenden Mediums und zur Drehzahl des sich drehenden Magneten (4) ist und nachfolgende Messung der Drehzahl des einfach polarisierten Magnetfeldes im weitgehend drehmomentlosen Zustand.
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Patent
DE102007046881A1 - 16.04.2009 -
Patent
DE102007046881B4 - 24.05.2012
Permalink: https://www.hzdr.de/publications/Publ-15565
Structure-induced coexistence of ferromagnetic and superconducting states of single-phase Bi3Ni seen via magnetization and resistance measurements
Herrmannsdörfer, T.; Skrotzki, R.; Wosnitza, J.; Köhler, D.; Boldt, R.; Ruck, M.
Abstract
We demonstrate the coexistence of superconductivity and ferromagnetism in Bi3Ni nanostructures that have been prepared by making use of novel chemical-reaction paths. We have characterized their magnetic and superconducting properties by means of magnetometry and electrical-transport measurements. Other than in bulk geometry, submicrometer-sized particles and quasi-one-dimensional nanoscaled strains of single-phase Bi3Ni undergo ferromagnetic order. Superconductivity in confined Bi3Ni emerges in the ferromagnetically ordered phase and is stable up to remarkably high magnetic fields. Uniquely, ferromagnetic hysteresis at zero resistance is observed in nanostructured Bi3Ni.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
- Physical Review B 83(2011), 140501(R)
Permalink: https://www.hzdr.de/publications/Publ-15564
Magnetoelectric effects in an organometallic quantum magnet
Zapf, V. S.; Sengupta, P.; Batista, C. D.; Nasreen, F.; Wolff-Fabris, F.; Paduan-Filho, A.
Abstract
Metal-organic materials constitute a new field in which to search for ferroelectricity and coupling between electricity and magnetism. We observe a magnetic field-induced change in the electric polarization, ΔP(H), that reaches 50 μC/m2 in single crystals of NiCl2–4SC(NH2)2 (DTN). DTN forms a tetragonal structure that breaks inversion symmetry with the electrically polar thiourea molecules [SC(NH2)] all tilted in the same direction along the c axis. The field H induces canted antiferromagnetism of the Ni S = 1 spins between 2 and 12 T and our measurements show that the electric polarization increases monotonically in this range, saturating above 12 T. By modeling the microscopic origin of this magnetoelectric effect, we find that the leading contribution to ΔP comes from the change in the crystal electric field, with a smaller contribution from magnetic exchange striction. The finite value of ΔP induced by magnetostriction results from the polar nature of the thiourea molecules bonded to the Ni atoms, and it is amplified by the softness of these organic molecules.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
- Physical Review B 83(2011), 140405(R)
Permalink: https://www.hzdr.de/publications/Publ-15563
Uranantwort von Bakterien und Pilzen
Schindler, F.; Günther, A.; Freihorst, D.; Haferburg, G.; Raff, J.; Kothe, E.
Abstract
Um die hohen Bindungskapazitäten und schnelle Mutationsrate von Bakterien, aber auch die bekanntermaßen hohen Aufnahmekapazitäten von Pilzen als Modell zu nutzen, werden die generellen, molekularen Aufnahmesysteme für Uran und die Bindungsformen in der Zelle beispielhaft für Bakterien und Pilze mit ihrer guten Bearbeitbarkeit untersucht. Dazu werden Mikroorganismen verwendet, für die molekulare Werkzeuge und Genomsequenzen vorliegen. Stämme mit Schwermetallresistenz werden genutzt, um die hier besonders stark ausgeprägten Systeme zur Entgiftung von Schwermetallen und damit auch der schweren Radioisotope zu nutzen. Der Nachweis der Aufnahme in die Zelle erfolgt durch Analyse der einzelnen zellulären Fraktionen, die mit spektroskopischen und mikroskopischen Methoden auf die vorherrschenden, molekularen Bindungsformen hin untersucht werden. Dabei werden die Modellorganismen Arthrobacter sp. JG37-Iso2 und Streptomyces acidiscabies E13 als Bakterien sowie der Weißfäulepilz Schizophyllum commune genutzt. Die Genomsequenz von Schizophyllum konnte genutzt werden, um Gene zu annotieren, die mit der Uranaufnahme zusammenhängen könnten. Dies ist nur durch Experimente wirklich möglich, da bisher keine Urantransporter in Eukarya gefunden wurden. Wir haben daher Proteomanalysen und Transkriptomanalysen durchgeführt, um die Expression unter verschiedenen Bedingungen zu testen, in denen der Pilz auf uranhaltigen Medien wächst. In Mikroarrays zeigen sich eine hohe Anzahl unterschiedlich regulierter Gene, deren Funktion experimentell überprüft wird. Ergänzend dazu wurde die Wechselwirkung von Schizophyllum mit Uran auf molekularer und zellulärer Ebene untersucht. Dabei konnte eine dominierende Wechselwirkung von Uran mit organischen Phosphatverbindungen auf und in der Zelle nachgewiesen werden. Bei der Untersuchung der Arthrobacter-Referenzstämme stellte sich heraus, dass eine Zellsorption der angebotenen U(VI) Spezies der dominante Prozess ist. Fluoreszenzspektroskopische Untersuchungen ergaben deutliche Unterschiede zwischen den U(VI) Spezies in den mineralischen Ausgangsmedien (freies U(VI), Uranylhydroxide bzw.Uranylhydroxocarbonat) und der sich über Carboxyl- und organischen Phosphatgruppen bildenden U(VI)- Spezies an der Bakterienzelle. Es konnten von schwermetallhaltigen Arealen der ehemaligen Wismut Region Pilzfruchtkörper gewonnen werden, die extrem hohe Anreicherungsfaktoren für Uran und Cäsium zeigen. Weiterhin konnte gezeigt werden, dass aus Pilzen sowie Gram-positiven und Gram-negativen Bakterien vom Standort lediglich 2 Isolate auf 50 μM Uranylacetat wachsen konnten. Diese beiden Stämme zeigten in der Laserablations-ICP-MS eine deutlich signifikante Urananreicherung im Bereich des Wachstums. Daneben wurden Streptomyces-Stämme auf ihre Resistenz gegenüber Uran getestet. Hier scheint sich ein anderer Mechanismus als bei Arthrobacter herauszustellen.
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 15562) publication
-
Lecture (Conference)
10. Internationales Symposium "Konditionierung radioaktiver Betriebs- und Stilllegungsabfälle", 06.-08.04.2011, Dresden, BRD -
Poster
10. Internationales Symposium "Konditionierung radioaktiver Betriebs- und Stilllegungsabfälle", 06.-08.04.2011, Dresden, BRD
Permalink: https://www.hzdr.de/publications/Publ-15562
P0718 - Anordnung zur optischen Tomographie
Hoppe, D.
Abstract
Die vorliegende Erfindung beschreibt eine Anordnung zur optischen Tomographie mit mindestens einem optischen Aufnehmer 5 und einem Untersuchungsobjekt 2 unter Verwendung von Spiegeln 1. Damit können sich schnell zeitlich verändernde oder bewegende Untersuchungsobjekte untersucht werden, ohne dass örtliche Veränderungen der optischen Aufnehmer (Kamera) oder der Spiegel notwendig sind.
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Patent
DE102007054669A1 - 28.05.2009
Permalink: https://www.hzdr.de/publications/Publ-15561
P0813 - Prozessmikroskop
Hampel, U.; Barthel, F.; Tschofen, M.
Abstract
Die Erfindung betrifft eine Anordnung zur optischen Visualisierung und Vermessung von mikroskopischen Vorgängen in Prozessen bei hoher Temperatur und/oder hohem Druck. Die Kamera- und die Beleuchtungseinheit sind in einem oder in getrennten Wärmeleitzylindern untergebracht um diese Einheiten vor unzulässig hohen Temperaturen, die am Prozessort auftreten, zu schützen ohne gleichzeitig einen starken Wärmeentzug aus dem Prozessmedium zu verursachen.
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Patent
DE102008058785 - Offenlegung 27.05.2010, Erteilung 16.02.2016
Permalink: https://www.hzdr.de/publications/Publ-15560
P0812 - Tetrathiol-Liganden, Metallkomplexe, Konjugate und Kits, deren Verwendung in der nuklearmedizinischen Diagnostik und Endoradionuklidtherapie sowie Verfahren zur Herstellung der Tetrathiol-Liganden und Metallkomplexe
Suhr, M.; Förster, C.; Pietzsch, H.-J.
Abstract
Ligand der Formel F1 worin (CH-R1) und (CH-R1') substituierte oder unsubstituierte Methylenbrücken darstellen, die einzelnen R1 und R1', sowie R3 und R3' jeweils unabhängig voneinander ausgewählt sind aus Wasserstoff, substituierten oder unsubstituierten Alkylgruppen, substituierten oder unsubstituierten Arylgruppen, m und n positive ganze Zahlen sind, wobei m die Anzahl der Gruppen (CH-R1') und n die Anzahl der Gruppen (CH-R1) repräsentiert, wobei die Summe aus m und n im Bereich von 4 bis 10 liegt, R2 und R2' unabhängig voneinander ausgewählt sind aus Wasserstoff, substituierten oder unsubstituierten Alkylgruppen, substituierten oder unsubstituierten Carboxylgruppen, substituierten oder unsubstituierten Arylgruppen oder Z, X eine substituierte oder unsubstituierte Methylenbrücke mit der Formel CHR4 oder eine unsubstituierte Aminogruppe (N-H) oder substituierte Aminogruppe (N-Z) ist, wobei Z für -(CH-R5)p-A steht, worin (CH-R5) eine substituierte oder unsubstituierte Methylenbrücke darstellt und p eine ganze Zahl ist, die für die Anzahl der Gruppen (CH-R5) steht, wobei p im Bereich von 2 bis 8 liegt, A eine kopplungsfähige Einheit darstellt, wobei R4 und die einzelnen R5 jeweils unabhängig voneinander ausgewählt sind aus Wasserstoff, substituierten oder unsubstituierten Alkylgruppen, substituierten oder unsubstituierten Arylgruppen.
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Patent
DE102009029033A1 - 24.06.2010
Permalink: https://www.hzdr.de/publications/Publ-15559
P0814 - Anordnung und Verfahren zur Erzeugung einzelner relativistischer Elektronen
Naumann, L.; Lehnert, U.; Kotte, R.; Wagner, A.
Abstract
The arrangement has an electron accelerator with accelerator cavities, and strewing targets (3) positioned between the accelerator cavities. The strewing targets are electron-optically thin. Multiple strewing targets are used between the cavities. An independent claim is also included for a method for producing individual relativistic electrons.
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Patent
DE102008054676A1 - 01.07.2010 -
Patent
DE 102008054676 B4 - 30.06.2011
Permalink: https://www.hzdr.de/publications/Publ-15558
Years: 2024 2023 2022 2021 2020 2019 2018 2017 2016
Pages: [1.] [2.] [3.] [4.] [5.] [6.] [7.] [8.] [9.] [10.] [11.] [12.] [13.] [14.] [15.] [16.] [17.] [18.] [19.] [20.] [21.] [22.] [23.] [24.] [25.] [26.] [27.] [28.] [29.] [30.] [31.] [32.] [33.] [34.] [35.] [36.] [37.] [38.] [39.] [40.] [41.] [42.] [43.] [44.] [45.] [46.] [47.] [48.] [49.] [50.] [51.] [52.] [53.] [54.] [55.] [56.] [57.] [58.] [59.] [60.] [61.] [62.] [63.] [64.] [65.] [66.] [67.] [68.] [69.] [70.] [71.] [72.] [73.] [74.] [75.] [76.] [77.] [78.] [79.] [80.] [81.] [82.] [83.] [84.] [85.] [86.] [87.] [88.] [89.] [90.] [91.] [92.] [93.] [94.] [95.] [96.] [97.] [98.] [99.] [100.] [101.] [102.] [103.] [104.] [105.] [106.] [107.] [108.] [109.] [110.] [111.] [112.] [113.] [114.] [115.] [116.] [117.] [118.] [119.] [120.] [121.] [122.] [123.] [124.] [125.] [126.] [127.] [128.] [129.] [130.] [131.] [132.] [133.] [134.] [135.] [136.] [137.] [138.] [139.] [140.] [141.] [142.] [143.] [144.] [145.] [146.] [147.] [148.] [149.] [150.] [151.] [152.] [153.] [154.] [155.] [156.] [157.] [158.] [159.] [160.] [161.] [162.] [163.] [164.] [165.] [166.] [167.] [168.] [169.] [170.] [171.] [172.] [173.] [174.] [175.] [176.] [177.] [178.] [179.] [180.] [181.] [182.] [183.] [184.] [185.] [186.] [187.] [188.] [189.] [190.] [191.] [192.] [193.] [194.] [195.] [196.] [197.] [198.] [199.] [200.] [201.] [202.] [203.] [204.] [205.] [206.] [207.] [208.] [209.] [210.] [211.] [212.] [213.] [214.] [215.] [216.] [217.] [218.] [219.] [220.] [221.] [222.] [223.] [224.] [225.] [226.] [227.] [228.] [229.] [230.] [231.] [232.] [233.] [234.] [235.] [236.] [237.] [238.] [239.] [240.] [241.] [242.] [243.] [244.] [245.] [246.] [247.] [248.] [249.] [250.] [251.] [252.] [253.] [254.] [255.] [256.] [257.] [258.] [259.] [260.] [261.] [262.] [263.] [264.] [265.] [266.] [267.] [268.] [269.] [270.] [271.] [272.] [273.] [274.] [275.] [276.] [277.] [278.] [279.] [280.] [281.] [282.] [283.] [284.] [285.] [286.] [287.] [288.] [289.] [290.] [291.] [292.] [293.] [294.] [295.] [296.] [297.] [298.] [299.] [300.] [301.] [302.] [303.] [304.] [305.] [306.] [307.] [308.] [309.] [310.] [311.] [312.] [313.] [314.] [315.] [316.] [317.] [318.] [319.] [320.] [321.] [322.] [323.] [324.] [325.] [326.] [327.] [328.] [329.] [330.] [331.] [332.] [333.] [334.] [335.] [336.] [337.] [338.] [339.] [340.] [341.] [342.] [343.] [344.] [345.] [346.] [347.] [348.] [349.] [350.] [351.] [352.] [353.] [354.] [355.] [356.] [357.] [358.] [359.] [360.] [361.] [362.] [363.] [364.] [365.] [366.] [367.] [368.]