Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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27694 Publications
Simultaneous loss of interlayer coherence and long-range magnetism in quasi-two-dimensional PdCrO2
Ghannadzadeh, S.; Licciardello, S.; Arsenijevic, S.; Robinson, P.; Takatsu, H.; Katsnelson, M. I.; Hussey, N. E.
Abstract: In many layered metals, coherent propagation of electronic excitations is often confined to the highly conducting planes. While strong electron correlations and/or proximity to an ordered phase are believed to be the drivers of this electron confinement, it is still not known what triggers the loss of interlayer coherence in a number of layered systems with strong magnetic fluctuations, such as cuprates. Here, we show that a definitive signature of interlayer coherence in the metallic-layered triangular antiferromagnet PdCrO2 vanishes at the Néel transition temperature. Comparison with the relevant energy scales and with the isostructural non-magnetic PdCoO2 reveals that the interlayer incoherence is driven by the growth of short-range magnetic fluctuations. This establishes a connection between long-range order and interlayer coherence in PdCrO2 and suggests that in many other low-dimensional conductors, incoherent interlayer transport also arises from the strong interaction between the (tunnelling) electrons and fluctuations of some underlying order. Registration No. 25468 - Permalink

Drastic change of the Fermi surface across the metamagnetic transition in CeRh2Si2
Götze, K.; Aoki, D.; Lévy-Bertrand, F.; Harima, H.; Sheikin, I.
Abstract: We report high field de Haas–van Alphen (dHvA) effect measurements in CeRh2Si2 both below and above the first-order 26 T metamagnetic transition from an antiferromagnetic to a polarized paramagnetic state. The dHvA frequencies observed above the transition are much higher than those observed below, implying a drastic change of the Fermi-surface size. The dHvA frequencies above the transition and their angular dependence are in good agreement with band-structure calculations for LaRh2Si2, which correspond to CeRh2Si2 with localized f electrons. Given that the f electrons are also localized at low fields in CeRh2Si2, the Fermi-surface reconstruction is due to the suppression of antiferromagnetism and the restoration of the crystallographic Brillouin zone rather than the delocalization of the f electrons. This example suggests that the intuitive notation of “small” and “large” Fermi surfaces commonly used for localized and itinerant f electrons, respectively, requires careful consideration, taking into account the modification of the Brillouin zone in the antiferromagnetic state, when interpreting experimental results. Registration No. 25467 - Permalink

Microstructure evolution of predefined catalysts for diameter-controlled growth of single-walled carbon nanotubes
Melkhanova, S.; Haluska, M.; Hübner, R.; Gemming, S.; Krause, M.
Abstract: Predefined catalysts have been recently successfully employed for diameter- and chirality-selective CVD growth of single-walled carbon nanotubes (SWCNTs).[1-3] They simplify the exhausting optimization of parameters for in situ catalyst formation and ensure a very good control of catalyst properties. Using C:Ni nanocomposite templates (NCTs) as catalyst precursors, SWCNTs with a selective, monomodal diameter distribution were obtained. More than the half of the SWCNTs had a diameter of (1.36±0.10) nm.[3]

While the preparation of NCTs is well defined and controlled, the activation of the NPs for nanotube synthesis by CVD is a critical step that is still not fully understood. Element-resolved scanning and high-resolution transmission electron microscopy and Raman spectroscopy were used to clarify the microstructure of C:Ni NCTs in the different stages of the SWCNT growth. These studies reveal a distinct change of the NCT microstructure by conserving the initial nanocomposite morphology to a very large extend.

[1] F. Yang et al., Nature 510, 522 (2014);
[2] H. An et al., Nanoscale 8, 14523 (2016);
[3] S. Melkhanova et al., Nanoscale 8, 14888 (2016)
Keywords: Single-walled carbon nanotubes, nanocomposites, catalysis, Raman spectroscopy, transmission electron microscopy
  • Poster
    XXXIstInternational Winterschool on Electronic Properties of Novel Materials, 04.-11.03.2017, Kirchberg, Österreich
Registration No. 25461 - Permalink

Giant Enhancement of Nonlinear Optical Response in Nd:YAG Single Crystals by Embedded Silver Nanoparticles
Li, R.; Dong, N.; Cheng, C.; Ren, F.; Hübner, R.; Wang, J.; Zhou, S.; Chen, F.
Abstract: We report on the enhancement and modulation of nonlinear optical response in an Nd:Y3Al5O12 (Nd:YAG) laser crystal through embedded silver nanoparticles (NPs) fabricated by Ag+ ion implantation. The linear absorption spectrum of the sample clearly reveals a localized surface plasmon resonance (SPR) band from 350 to 700 nm correlated to the Ag NPs. By using the Z-scan technique with femtosecond pulses at a wavelength of 515 nm, which is considered as an optical excitation within the SPR band, the nonlinear refraction index reaches values as high as ∼10–12 cm2/W, enhanced by ∼4 orders of magnitude in comparison to that of unimplanted Nd:YAG (without Ag NPs). In addition, it has been shown that embedded Ag NPs in the Nd:YAG host reveal saturable absorption signifying the nonlinear responses. We have also observed that the nonlinear absorption coefficients depend significantly on the excitation energy and can be modulated by varying the fluence of Ag+ ions. Registration No. 25456 - Permalink

Swift heavy ion track formation in SrTiO3 and TiO2 under random, channeling and near-channeling conditions
Karlušić, M.; Jakšić, M.; Lebius, H.; Ban-D'Etat, B.; Wilhelm, R. A.ORC; Heller, R.; Schleberger, M.
Abstract: Conditions for ion track formation in single crystal SrTiO3 and TiO2 (rutile) after irradiations using swift heavy ion beams with specific energies below 1 MeV/amu were investigated in this work. Rutherford backscattering spectroscopy in channeling was used to measure ion tracks in the bulk, while atomic force microscopy was used for observation of ion tracks on the surfaces. Variations in the ion track sizes and respective thresholds were observed after irradiations under random, channeling and near-channeling conditions close to normal incidence. These variations are attributed to the specifics of the electronic stopping power of swift heavy ions under the investigated conditions. In the case of ion channeling, electronic stopping power is reduced and observed ion tracks are smaller. The opposite was found under the near-channeling conditions when lowering of the ion track formation threshold was observed. We attribute this finding to the oscillating electronic stopping power with large peak values. For both materials, thresholds for bulk and surface ion track formation were found to be surprisingly close, around 10 keV nm−1. Obtained results are compared with predictions of the analytical thermal spike model.
Keywords: SrTiO3, TiO2, swift heavy ion, ion track, thermal spike, RBS/c, AFM

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Registration No. 25451 - Permalink

Effect of flow non-idealities on tray efficiency
Vishwakarma, V.; Schubert, M.; Hampel, U.
Abstract: Cross-flow trays are highly reputed among vapour-liquid contacting devices in distillation columns. Their ability to perform in various operating conditions, low fouling sensitivity, low cost and access for inspections make them potential nominee for column internals. Tray separation efficiency as well as overall performance of the column is strongly dictated by evolving flow patterns on the tray. Liquid plug flow is considered ‘ideal’ at which the maximum tray efficiency can be expected. On the other hand, liquid channelling, bypassing, retrograde flow and stagnant zones are known to be detrimental to tray efficiency. Schubert et. al. (2016) established the wire-mesh sensor as a novel technique to extract liquid flow patterns on trays and presented the effect of variable liquid load and weir design on the flow patterns.
As a follow up, the most common mathematical models, which were recently revisited by Vishwakarma et al. (2016), are applied to associate flow and mixing patterns with tray efficiency. They indicate serious loss in efficiency for the tray with largest stagnant regions. The location of dead zones is also important as most of the mass transfer on large trays happens in their first half. Any stagnant liquid in these areas is highly disadvantageous for the tray to fractionate as per expectations. This contribution will stimulate to develop a new practicable model that can account for the effect of location and type of non-ideality on the tray efficiency.

(1) M. Schubert, M. Piechotta, M. Beyer, E. Schleicher, U. Hampel and J. Paschold, ‘An imaging technique for characterization of fluid flow pattern on industrial-scale column sieve trays’, Chemical Engineering Research and Design, vol. 111, pp.138–146, 2016.
(2) V. Vishwakarma, M. Schubert and U. Hampel, ‘Distillation tray efficiency modelling: a forgotten chapter’, Jahrestreffen der ProcessNet-Fachgruppe Fluidverfahrenstechnik, 16-17 March 2016, Garmisch-Partenkirchen.
  • Lecture (Conference)
    Jahrestreffen der ProcessNet-Fachgruppe Fluidverfahrenstechnik, 08.-10.03.2017, Cologne, Germany
Registration No. 25435 - Permalink

Experimentelle Untersuchungen zur Speziesumwandlung bei Absorption von CO2 in einer Blasensäule
Kipping, R.; Kryk, H.; Hampel, U.
Abstract: Blasensäulenreaktoren zählen aufgrund ihrer einfachen Bauweise und ihres ausgezeichneten Wärme-und Stofftransportverhaltens zu einem der häufig genutzten Reaktortypen in der chemischen Industrie. Gegenstand aktueller Forschungsarbeiten innerhalb des DFG Schwerpunktprogramms 1740 „Reaktive Blasenströmungen“ ist die Untersuchung lokaler Transportprozesse, um das Verständnis über die Kopplung von Hydrodynamik und Stofftransport bei reaktiven 2-Phasenströmungen in Blasensäulen zu verbessern. Aufgrund limitierter Messtechnik stellt die Ermittlung von lokalen Konzentrationsfeldern und Stofftransportraten in dichten Blasenströmungen eine besondere Herausforderung dar. In diesem Beitrag werden experimentelle Untersuchungen zum Stofftransport am Beispiel der chemischen Absorption von CO2 vorgestellt, bei der die am HZDR entwickelte Gittersensormesstechnik zur Ermittlung der Konzentration und der Umwandlung ionischer Spezies eingesetzt wird. Für diesen Zweck konnte der Gittersensor anhand eines theoretischen Modells und Validierungsexperimente erfolgreich qualifiziert werden. Die experimentellen Ergebnisse der Stofftransportuntersuchungen in einem Blasensäulenreaktor zeigen die Stofftransportraten für verschiedene Eingangsparameter (z.B. Eingangskonzentration der Natronlauge und Gasdurchsatz des CO2) sowohl in Abhängigkeit des Radius als auch in verschiedenen Höhen des Reaktors.
  • Poster
    Jahrestreffen der ProcessNet-Fachgruppen Mehrphasenströmungen, Partikelmesstechnik, Zerkleinern und Klassieren, Computational Fluid Dynamics, Mischvorgänge und dem TAK Aerosoltechnologie, 14.-15.03.2017, Dresden, Deutschland
Registration No. 25431 - Permalink

Dynamics of a particle attachment to an immersed bubble
Lecrivain, G.; Yamamoto, R.; Hampel, U.; Taniguchi, T.
Abstract: We propose an extended smooth profile method which can deal with particle-dynamics dispersed in a binary fluid. The smooth profile method, originally developed for the simulation of particle transport in a homogeneous fluid, has been successfully combined with a binary fluid model based on Ginzburg-Landau free energy functional. In this approach, the three types of interfaces among particles and two fluids are treated as diffuse interfaces. By using the method, we simulated the attachment and detachment dynamics of a colloidal particle to the surface of a position fixed bubble in a Newtonian fluid under various capillary numbers. It is found that the method can reproduce the three micro-processes associated with the particle attachment ((i) particle approach, (ii) collision, (iii) sliding down on the bubble surface) (Gregory et al, 2016). The present method will make it possible to simulate a froth flotation process, where the capture of hydrophobic particles by rising bubbles is of primary importance.
Keywords: Flotation; Direct Numerical Simulation; Smoothed Profile Method; Immersed Boundary Method
  • Contribution to proceedings
    3rd International Symposium on Multiscale Multiphase Process Engineering (MMPE), 08.-11.05.2017, Toyama, Japan
Registration No. 25428 - Permalink

Discrete Single Crystalline Titanium Oxide Nanoparticle Formation from a Two-Dimensional Nanowelded Network
Dhal, S.; Chatterjee, S.; Facsko, S.; Möller, W.; Böttger, R.; Satpati, B.; Ratha, S.; Hübner, R.
Abstract: Nanostructured materials are gaining increasing importance due to their unique properties resulting from the high surface to volume ratio and the altered characteristics of the nanoscaled building blocks. The properties of these materials depend strongly on their microstructure and thus can be controlled by inducing transformation on the nanoscale. In this work, a simple low energy ion beam irradiation technique is presented that can be used to effectively weld the hydrogen titanate nanotubes into a large-scale network of nanowires. By varying the ion fluence, we are able to fragment the entire nanowire network into uniformly distributed nanocrystalline particles with an average size of 5 ± 2 nm. Three-dimensional computer simulations of the ion irradiation effects on the nanotubes reproduce most of the experimental findings and thus confirm that the early development of the system is governed by atomic collision processes. Our study demonstrates that the selective use of ion irradiation can transform metal-oxide nanotubes into large-scale welded networks of nanowires and further into nanocrystalline particles through nucleation and growth.
Keywords: ion irradiation, titanium oxide, nanowelding, nanoparticle Registration No. 25425 - Permalink

A study of the behaviour of copper in different types of silicate glasses implanted with Cu+ and O+ ions
Švecová, B.; Vařák, P.; Vytykáčová, S.; Nekvindová, P.; Macková, A.; Malinský, P.; Böttger, R.
Abstract: Glasses containing copper are promising photonic materials for lasing devices and all-optical components. It has already been shown that the oxidation state of the implants depends on many factors. This paper is going to report on one of them, i.e. the influence of the composition of a silicate glass matrix on the behaviour of the implanted Cu ions before and after a subsequent implantation of oxygen ions.
Three types of silicate glasses having a different extent of cross-linking were implanted with copper ions with an energy of 330 keV and a fluence 1 × 1016 ions cm−2. Then the glasses were implanted with oxygen ions with an energy of 110 keV into the same depth as the already implanted Cu ions. The concentration depth profiles of Cu in the glasses were studied by Rutherford Backscattering Spectrometry. After the implantation, the samples were characterised by optical absorption and photoluminescence spectroscopy. The samples were annealed in ambient atmosphere for 1 h at 600 °C, which is near the transformation temperature of those glasses. The effect of annealing on the distribution of the implants and on the absorption and emission spectra of the as-implanted glasses will be discussed as well
Keywords: Silicate glasses; Ion implantation; Copper; Oxygen

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Registration No. 25424 - Permalink

Molecular Doping of a High Mobility Diketopyrrolopyrrole- Dithienylthieno[3,2-b]thiophene Donor-Acceptor Copolymer with F6TCNNQ
Karpov, Y.; Erdmann, T.; Stamm, M.; Lappan, U.; Guskova, O.; Malanin, M.; Raguzin, I.; Beryozkina, T.; Bakulev, V.; Günther, F.; Gemming, S.; Seifert, G.; Hambsch, M.; Mannsfeld, S.; Voit, B.; Kiriy, A.
Abstract: Herein we present a molecular doping of a high mobility diketopyrrolopyrrole–dithienylthieno[3,2-b]thiophene donor–acceptor copolymer poly[3,6-(dithiophene-2-yl)-2,5-di(6-dodecyloctadecyl)pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thieno[3,2-b]thiophene], PDPP(6-DO)2TT, with the electron-deficient compound hexafluorotetracyanonaphthoquinodimethane (F6TCNNQ). Despite a slightly negative HOMO(donor)–LUMO(acceptor) offset of −0.12 eV which may suggest a reduced driving force for the charge transfer (CT), a partial charge CT was experimentally observed in PDPP(6-DO)2TT:F6TCNNQ by absorption, vibrational, and electron paramagnetic resonance spectroscopies and predicted by density functional theory calculations. Despite the modest CT, PDPP(6-DO)2TT:F6TCNNQ films possess unexpectedly high conductivities up to 2 S/cm (comparable with the conductivities of the benchmark doped polymer system P3HT:F4TCNQ having a large positive offset). The observation of the high conductivity in doped PDPP(6-DO)2TT films can be explained by a high hole mobility in PDPP(6-DO)2TT blends which compensates a lowered (relatively to P3HT:F4TCNQ) concentration of free charge carriers. We also show that F6TCNNQ-doped P3HT, the system which has not been reported so far to the best of our knowledge, exhibits a conductivity up to 7 S/cm, which exceeds the conductivity of the benchmark P3HT:F4TCNQ system.
Keywords: organic electronics, molecular doping, p-dopant, conjugated polymer, electrical conductivity, charge transfer complex

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Registration No. 25413 - Permalink

Effect of Acid Washing on the Oxygen Reduction Reaction Activity of Pt-Cu Aerogel Catalysts
Henning, S.; Kühn, L.; Herranz, J.; Nachtegaal, M.; Hübner, R.; Werheid, M.; Eychmüller, A.; Schmidt, T. J.
Abstract: Developing highly active and durable oxygen reduction reaction (ORR) catalysts is crucial to reduce the cost of polymer electrolyte fuel cells (PEFCs). To meet those requirements, unsupported Pt-Cu alloy nanochains (aerogels) were synthesized by a simple co-reduction route in aqueous solution and their structure was characterized by X-ray absorption spectroscopy and scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy. These catalysts exceeded the ORR activity of commercial Pt/C catalysts by more than 100% in rotating disk electrode (RDE) experiments and met the corresponding US DOE target for automotive PEFC implementation, thereby qualifying as very promising materials. The behavior of Pt-Cu aerogels under PEFC operation conditions was mimicked by acid washing experiments which showed that the Cu content in the alloy phase and ORR activity decrease through this step. Comparing composition, structure and ORR activity for various specimens, the Cu content in the alloy phase was identified as the main descriptor of ORR activity. An almost linear correlation was found between those two parameters and complemented by supporting data from the literature.
Keywords: Aerogels; Dealloying; ORR; PEFC; X-ray absorption Registration No. 25412 - Permalink

Magnetic properties of a Ho2Fe14Si3 single crystal
Andreev, A. V.; Gorbunov, D. I.; Skourski, Y.; Kuz'Min, M. D.; Tereshina, E. A.; Henriques, M. S.
Abstract: Magnetization of a Ho2Fe14Si3 single crystal was measured in a steady magnetic field of up to 9 T and in pulsed fields of up to 60 T applied along the principal axes. Ho2Fe14Si3 is a ferrimagnet below TC = 480 K, has a spontaneous magnetic moment of about 8 µB/f.u. (at T = 4.2 K) and exhibits a large easy-plane magnetic anisotropy. There is also a certain anisotropy within the basal plane, the b axis [120] being the easy-magnetization direction. In fields applied along the a and b axes field-induced first-order phase transitions are observed at 29 T and at 22 T, respectively. Along the easy axis b we observe also an S-shaped anomaly at about 47 T, which does not correspond to a phase transition. A simple model predicts that the two observed first-order transitions are the only ones taking place in Ho2Fe14Si3; the magnetization should subsequently grow continuously and arrive at saturation at ~100 T. This is in stark contrast to the behavior of the parent compound Ho2Fe17, where as many as three sequential first-order transitions are expected for H‖b. The reason for the disparity is that the basal-plane anisotropy constant KHo is at least one order of magnitude smaller in Ho2Fe14Si3 than it is in Ho2Fe17. Registration No. 25409 - Permalink

Deep sub-threshold φ production and implications for the K+/K- freeze-out in Au+Au collisions
Adamczewski-Musch, J.; Arnold, O.; Behnke, C.; Belounnas, A.; Belyaev, A.; Berger-Chen, J. C.; Biernat, J.; Blanco, A.; Blume, C.; Böhmer, M.; Bordalo, P.; Chernenko, S.; Chlad, L.; Deveaux, C.; Dreyer, J.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Filip, P.; Fonte, P.; Franco, C.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzon, J. A.; Gernhäuser, R.; Golubeva, M.; Guber, F.; Gumberidze, M.; Harabasz, S.; Heinz, T.; Hennino, T.; Hlavac, S.; Höhne, C.; Holzmann, R.; Ierusalimov, A.; Ivashkin, A.; Kämpfer, B.; Karavicheva, T.; Kardan, B.; Koenig, I.; Koenig, W.; Kolb, B. W.; Korcy, G.; Kornakov, G.; Kotte, R.; Kühn, W.; Kugler, A.; Kunz, T.; Kurepin, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Lorenz, M.; Mahmoud, T.; Maier, L.; Mangiarotti, A.; Markert, J.; Maurus, S.; Metag, V.; Michel, J.; Mihaylov, D. M.; Morozov, S.; Müntz, C.; Münzer, R.; Naumann, L.; Nowakowski, K. N.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Petukhov, O.; Pietraszko, J.; Przygoda, W.; Ramos, S.; Ramstein, B.; Reshetin, A.; Rodriguez-Ramos, P.; Rosier, P.; Rost, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schuldes, H.; Schwab, E.; Scozzi, F.; Seck, F.; Sellheim, P.; Siebenson, J.; Silva, L.; Sobolev, Y. G.; Spataro, S.; Ströbele, H.; Stroth, J.; Strzempek, P.; Sturm, C.; Svoboda, O.; Szala, M.; Tlusty, P.; Traxler, M.; Tsertos, H.; Usenko, E.; Wagner, V.; Wendisch, C.; Wiebusch, M. G.; Wirth, J.; Zanevsky, Y.; Zumbruch, P.
Abstract: We present first data on charged kaons and {\phi} mesons in Au+Au collisions at a kinetic beam energy of 1.23A GeV. As observed already at slightly higher beam energies, we find significantly different slopes for the K+ and K- transverse-mass spectra, and no significant increase of the the K-/K+ multiplicity ratio with increasing centrality of the collision. The {\phi}/K- multiplicity ratio is found to be surprisingly high with a value of 0.52 ± 0.16 and shows no dependence on the centrality, either. The different slopes of the K+ and K- spectra can be explained by feed-down from {\phi} mesons, which substantially softens the spectra of K- mesons.

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Registration No. 25408 - Permalink

Source term and activation analysis for the new cyclotron for medical applications at HZDR with MCNP6 and FLUKA
Müller, S. E.ORC; Konheiser, J.; Naumann, B.; Ferrari, A.; Magin, A.
Abstract: A new cyclotron is currently being commissioned at the Center of Radiopharmaceutical Cancer Research of the HZDR. The energy range of up to 28 MeV protons for the 18O(p,n)18F reaction required a recalculation of the neutron source terms needed in the shielding calculations, since the manufacturer supplied data was based on a 24 MeV proton beam. The radiation transport programs MCNP6 and FLUKA were used to calculate the neutron fluence emerging from the 18O-enriched water target during operation. Both Monte Carlo programs agree within 20 % on the neutron yield per incident proton for 24 and 28 MeV proton beams, while at 24 MeV, the manufacturer supplied data is considerably lower than the simulation results. To validate the radiation fields obtained in the simulations, an experimental program has been started using activation samples which are placed close to the water target of the cyclotron which is currently used to produce 18F. After irradiation, the samples are analyzed, and the resulting activation is compared to Monte Carlo calculations of the expected sample activation.
  • Lecture (Conference)
    DPG Spring Meeting 2017, 27.-31.03.2017, Münster, Germany
Registration No. 25401 - Permalink

Rückhaltung von U(VI) und Eu(III) an Ca-Bentonit und CSH-Phasen unter hoch salinaren und alkalischen Bedingungen
Wolter, J.-M.; Philipp, T.; Lippold, H.; Schmeide, K.; Stumpf, T.
Abstract: Leaching experiments of uranium(VI) doped calcium-silicate-hydrate (CSH) phases with various calcium to silicon ratios were carried out in NaCl, NaCl/Na2SO4, NaCl/NaHCO3 and NaHCO3 containing solutions to study the time-dependent release of Ca, Si and U. Potential changes of the U(VI)-CSH binding induced by leaching were monitored with time-resolved laser-induced fluorescence spectroscopy (TRLFS), infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD).
  • Lecture (others)
    4. Workshop des BMWi-Verbundvorhabens “Geochemische Radionuklidrückhaltung an Zementalterationsphasen (GRaZ)“, 05.-06.04.2017, Mainz, Deutschland
Registration No. 25399 - Permalink

Evaluation of hemodynamic impairments in unilateral high-grade carotid artery stenosis patients and healthy age-matched participants
Kaczmarz, S.; Göttler, J.; Griese, V.; Petr, J.ORC; Zimmer, C.; Sorg, C.; Preibisch, C.
Abstract: Objectives:
Internal carotid-artery stenosis (ICAS) is a major public health issue, as it accounts for approximately 20% of all strokes1. However, related complex hemodynamic impairments are not well understood2. We therefore propose a multimodal MRI-protocol. The major aims were to evaluate its reliability and investigate physiological changes.
Methods:
In the ongoing clinical study, 52 subjects (29 healthy controls: 70.3±4.7y, 13 males; 23 patients with asymptomatic unilateral ICAS, NASCET>70%: 70.5±6.8y, 15 males) underwent MRI on a Philips 3T-Ingenia. We propose a combination of three different MR-based methods, accounting for cerebrovascular reactivity (CVR) by breathhold-fMRI (voxelsize 3x3x3mm3, 38 slices, TE/TR=30ms/1200ms, acq.time=5:48min), CBF by pCASL (3D-readout, voxelsize 2.7x2.8x6mm3, 16 slices, TE/TR=7.4ms/4403ms, label duration=1800ms, PLD=2000ms, acq.time 5:43min) and relative oxygen extraction fraction (rOEF) by a multi-parametric quantitative-BOLD approach3 (voxelsize 2x2x3mm3, 30 slices). For each participant, individual masks of watershed areas were defined for both hemispheres in grey-matter and mean values of all three modalities were compared.
Results:
In healthy participants, our results show no significant lateralization of all three modalities on a group level. For ICAS-patients, regionally reduced CVR (p=0.003) as well as hypoperfusion (p< 0.001) were found ipsilateral to the stenosis (figure). In accordance with the literature, we did not find ICAS-induced changes in oxygen extraction on a group level (p=0.310).4 Even though focal rOEF increases could be suspected in single patients.
Conclusions:
The presented preliminary results thus imply successful application of our multimodal-MRI approach and are highly promising with respect to gaining a deeper insight into ICAS-related physiological changes. Further investigations of the relations between the parameters are currently in progress.
  • Contribution to proceedings
    28rd International Symposium on Cerebral Blood Flow, Metabolism and Function, 01.04.2017, Berlin, Germany
    Proceedings of the 28rd International Symposium on Cerebral Blood Flow, Metabolism and Function
Registration No. 25394 - Permalink

The Common Data Acquisition Platform in the Helmholtz Association
Kaever, P.; Balzer, M.; Kopmann, A.; Zimmer, M.; Rongen, H.
Abstract: Various centres of the German Helmholtz Association (HGF) started in 2012 to develop a modular data acquisition (DAQ) platform, covering the entire range from detector readout to data transfer into parallel computing environments. This platform integrates generic hardware components like the multi-purpose HGF-Advanced Mezzanine Card or a smart scientific camera framework, adding user value with Linux drivers and board support packages. Technically the scope comprises the DAQ-chain from FPGA-modules to computing servers, notably frontend-electronics-interfaces, microcontrollers and GPUs with their software plus high-performance data transmission links. The core idea is a generic and component-based approach, enabling the implementation of specific experiment requirements with low effort. This so called DTS-platform will support standards like MTCA.4 in hard- and software to ensure compatibility with commercial components. Its capability to deploy on other crate standards or FPGA-boards with PCI express or Ethernet interfaces remains an essential feature. Competences of the participating centres are coordinated in order to provide a solid technological basis for both research topics in the Helmholtz Programme "Matter and Technology", "Detector Technology and Systems" and "Accelerator Research and Development". The DTS-platform aims at reducing costs and development time and will ensure access to latest technologies for the collaboration. Due to its flexible approach, it has the potential to be applied in other scientific programs.
Keywords: Data acquisition concepts; Software architectures (event data models, frameworks and databases); Detector control systems (detector and experiment monitoring and slow-control systems, architecture, hardware, algorithms, databases); Image reconstruction in medical imaging
  • Contribution to proceedings
    Topical Workshop on Electronics for Particle Physics (TWEPP2016), 26.-30.09.2016, Karlsruhe, Deutschland
    Journal of Instrumentation 12(2017),C04004: IOPscience
    DOI-Link: http://dx.doi.org/10.1088/1748-0221/12/04/C04004
Registration No. 25393 - Permalink

Electronic Structure Simulation of Thin Silicon Layers: Impact of Orientation, Confinement, and Strain
Joseph, T.; Fuchs, F.; Schuster, J.; Schulz, S. E.
Abstract: Fully Depleted Silicon on Insulator transistors (FDSOI) are a promising approach for further scaling. The device features a fully depleted body which is isolated by an insulator box. This introduces better electrostatics, lower leakage current and thus better channel control. The device performance is heavily influenced by the orientation, confinement and strain in the ultra-thin body. In this work the electronic structure of ultra-thin silicon layers is investigated using Density Functional Theory (DFT). The simulation parameters for the model system were calibrated to reproduce the experimental band gap of bulk silicon. This ensures that the model describes the electronic structure of ultra-thin silicon layers accurately. Our study demonstrates the impact of confinement, orientation and strain on material dependent transport properties and their influence on the device performance. For this purpose our results will be used as an input for device simulations using Synopsys Sentaurus TCAD.
We find that the band gap of the silicon layer increases with decreasing slab thickness which is a clear indication of quantum confinement. From the simulation, the band gap for the {100} confinement is found to be higher than {110} and {111} scenarios. Band gap is one of the factors which influence the intrinsic carrier in the semiconductor and thereby the transport. Another important factor for the transport is lattice strain. Strain is a useful method for modulating band structures. One good example is the transformation of direct band gap in {100} confined silicon slab to indirect band gap with 2 % biaxial compression. In our presentation we will discuss the influence of the effective mass as well. Furthermore, the strain dependence of the electronic structure and its impact on device properties is analyzed systematically.
Keywords: silicon, confinement, density functional theory, FDSOI, strain engineering
  • Poster
    Material for Advanced Metallization (MAM), 26.-29.03.2017, Dresden, Deutschland
Registration No. 25392 - Permalink

Simulation of Reconfigurable Field-effect Transistors: Impact of the NiSi2-Si Interfaces, Crystal Orientation, and Strain
Fuchs, F.; Schuster, J.; Gemming, S.
Abstract: Reconfigurable transistors (RFETs) can be switched between electron and hole current by changing the polarity of the gate potential. This allows a much higher functionality and hence, logic operations can be realized with fewer transistors. The device performance of such a transistor is strongly dominated by the contact physics.
In this work, the electron transport across the NiSi 2 -Si interface is studied using the NEGF formalism and density functional theory, which allows us to consider the atomic structure of the interface. A new model is then presented which relates the electron transport through the interface to the transfer characteristic of an RFET. The model is compared to experimental data, which shows very good agreement, especially with respect to the ratio between electron and hole current (left figure).
Based on the model, different structure variations at the interface and their consequences on the device performance are discussed. It is demonstrated that best symmetry between electron and hole current is achieved for the <110> crystal orientation, which is much worse for <100> orientation (right figure). This makes the <110> orientation advantageous for RFETs. Also the influence of strain generated parallel to the interface plane is investigated (right figure). It is shown that strain can be used to tune the symmetry in case of <110> crystal orientation even further. This is entirely different for the <100> crystal orientation, where the highest electron currents are observed for all strain states. In this state, the electron currents are about three orders of magnitude higher than the hole currents. A detailed discussion of these differences based on work function and band structure analysis will be given in our contribution.
Keywords: reconfigurable transistor, RFET, density functional theory, metal-semiconductor interface
  • Lecture (Conference)
    Material for Advanced Metallization (MAM), 26.-29.03.2017, Dresden, Deutschland
Registration No. 25391 - Permalink

NiSi2-Si interfaces as building blocks for reconfigurable field-effect transistors: from the atomic structure to device characteristics
Fuchs, F.; Schuster, J.; Gemming, S.
Abstract: The electron transport across metal-semiconductor interfaces is crucial for the functionality of reconfigurable field-effect transistors, which can be switched between electron and hole current. Devices were already fabricated experimentally, however, a profound understanding of the underlaying mechanism is not yet available.
This study focuses on the NiSi2-Si interface, which is studied using the NEGF formalism. Based on the calculated transmission spectra, the transfer characteristic of a reconfigurable transistor is obtained using a simplified approach. Even though this model strongly simplifies the electrostatic environment in a transistor, very good agreement with experimental devices is demonstrated. The impact of strain on the device characteristic is studied as well. It is shown that the magnitude of electron and hole current can be altered successfully. They can also be tuned to be symmetric, which fits to experimental observations. Finally, new insight into the device functionality is gained based on our calculations of the work functions and effective masses of the isolated NiSi 2 and Si.
Keywords: reconfigurable transistor, RFET, density functional theory, metal-semiconductor interface
  • Lecture (Conference)
    DPG-Frühjahrstagung, 19.-24.03.2017, Dresden, Deutschland
Registration No. 25390 - Permalink

Engineering the Electronic Properties of Two-Dimensional Transition Metal Dichalcogenides by Introducing Mirror Twin Boundaries
Komsa, H.-P.; Krasheninnikov, A. V.ORC
Abstract: Grain boundaries in 2D materials can have marked influence on the material properties. The effects can be not only detrimental, but also beneficial in transition metal dichalcogenides (TMDs), so that controlling the density and type of the boundaries in these systems should be important for engineering their properties. However, this is often possibly only during the growth stage. Molybdenum and tungsten dichalcogenides feature a particular set of 60° mirror twin boundaries, which are reported to occur upon merging of the growing flakes, to appear during growth to accommodate for the nonstoichiometry of the sample, or to be produced a posteriori by electron irradiation or thermal annealing. Furthermore, different preparation conditions lead to different atomic structure of the boundary, which consequently exhibit different electronic properties. This has obviously garnered interest for the ability to control grain boundary types and densities. In this progress report, the recent experimental and theoretical work related to the characterization of mirror twin boundaries is reviewed. A consistent set of formation energies for the mirror twin boundaries is provided, which then allows a coherent picture on the formation mechanisms under different conditions to be drawn. Finally, the electronic structure of these boundaries is analyzed and their potential applications are discussed.
Keywords: 2D materials, first principles calculations

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  • Secondary publication expected from 01.03.2018
Registration No. 25387 - Permalink

Atomic defects and doping of monolayer NbSe2
Nguyen, L.; Komsa, H.-P.; Khestanova, E.; Kashtiban, R.; Peters, J. P.; Lawlor1, S.; Sanchez, A. M.; Sloan, J.; Gorbachev, R.; Grigorieva, I.; Krasheninnikov, A. V.ORC; Haigh, S. J.
Abstract: We have investigated the structure of atomic defects within monolayer NbSe2 encapsulated in graphene by combining atomic resolution transmission electron microscope imaging, density functional theory (DFT) calculations, and strain mapping using geometric phase analysis. We demonstrate the presence of stable Nb and Se monovacancies in monolayer material and reveal that Se monovacancies are the most frequently observed defects, consistent with DFT calculations of their formation energy. We reveal that adventitious impurities of C, N, and O can substitute into the NbSe2 lattice stabilizing Se divacancies. We further observe evidence of Pt substitution into both Se and Nb vacancy sites. This knowledge of the character and relative frequency of different atomic defects provides the potential to better understand and control the unusual electronic and magnetic properties of this exciting two-dimensional material.
Keywords: graphene, 2D materials, TEM, first-principles calculations

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  • Secondary publication expected from 14.02.2018
Registration No. 25386 - Permalink

EDTA and DTPA as scaffolds for successful Ln3+/An3+ separations from spent nuclear fuel
Langford-Paden, M. H.; Andrews, M. B.; Swinburn, A. N.; Alker, A.; Beal, K.; Anuar, N. S. B. K.; Knight, M. E.; Jones, J. E.; Beele, B.; Adam, C.; Panak, P.; Geist, A.; Kaden, P.; Natrajan, L. S.
Abstract: Multi-dentate ligands are instrumental to extraction and separations chemistry associated with nuclear fuel reprocessing. Specifically, the TALSPEAK (Trivalent Actinide Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexations) process utilises DTPA to facilitate the separation of minor actinides, MA3+ (Am3+ and Cm3+), from Ln3+ and Y3+, allowing the MA3+ to be reprocessed further by transmutation. The TALSPEAK process involves the preferential extraction of the major component (Ln3+) into the organic phase using HDEHP, while the DTPA-derived ligands remain in the aqueous phase coordinating MA3+ which favour soft donor interactions. The process requires the use of lactic acid as a buffer to maintain pH 3.6 in order to prevent the precipitation of DTPA complexes at low pH, commonly experienced during the processing cycle. Amino acid conjugates derived from EDTA and DTPA present ideal candidates as self-buffering DTPA/EDTA ligands, therefore removing the need for lactic acid in the TALSPEAK process. The ligands (right) produce an internal buffer pH 1.5-2.5 at μM to mM concentrations. The synthesis, coordination chemistry, photophysical properties and separation behaviour of these new ligands and stability towards ionising radiation is presented.
Keywords: Lanthanide(III), Actinide(III), amino acids, DTPA
  • Poster
    ThUL School in Actinide chemistry 2016, 19.-23.09.2016, Dresden, Deutschland
Registration No. 25385 - Permalink

Two-dimensional MoS2 under ion irradiation: from controlled defect production to electronic structure engineering
Ghorbani-Asl, M.; Kretschmer, S.; Spearot, D. E.; Krasheninnikov, A. V.ORC
Corresponding author: Krasheninnikov, A. V.
Abstract: Two-dimensional (2D) transition metal dichalcogenides (TMDs), like MoS2, have unique electronic and optical properties, which can further be tuned using ion bombardment and post-synthesis ion-beam mediated methods combined with exposure of the irradiated sample to precursor gases. The optimization of these techniques requires a complete understanding of the response of 2D TMDs to ion irradiation, which is affected by the reduced dimensionality of the system. By combining analytical potential molecular dynamics with first-principles calculations, we study the production of defects in free-standing MoS2 sheets under noble gas ion irradiation for a wide range of ion energies when nuclear stopping dominates, and assess the probabilities for different defects to appear. We show that depending on the incident angle, ion type and energy, sulfur atoms can be sputtered away predominantly from the top or bottom layers, creating unique opportunities for engineering mixed MoSX compounds where X are chemical elements from group V or VII. We study the electronic structure of such systems, demonstrate that they can be metals, and finally discuss how metal/semiconductor/metal junctions, which exhibit negative differential resistance, can be designed using focused ion beams combined with the exposure of the system to fluorine.
Keywords: Two-dimensional materials, ion irradiation, atomistic simulations, defects

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Registration No. 25384 - Permalink

Radiosynthesis of (S)-[18F]T1: The first PET radioligand for molecular imaging of α3β4 nicotinic acetylcholine receptors
Saramsamkan, J.; Fischer, S.; Deuther-Conrad, W.; Ludwig, F.-A.; Scheunemann, M.; Arunrungvichian, K.; Vajragupta, O.; Brust, P.
Abstract: Recent pharmacologic data revealed the implication of α3β4 nicotinic acetylcholine receptors (nAChRs) in nicotine and drug addiction. To image α3β4 nAChRs in vivo, we aimed to establish the synthesis of a [18F]-labelled analog of the highly affine and selective α3β4 ligand (S)-3-(4-(4-fluorophenyl)-1H-1,2,3-triazol-1-yl)quinuclidine ((S)-T1). (S)-[18F]T1 was synthesized from ethynyl-4-[18F]fluorobenzene ([18F]5) and (S)-azidoquinuclidine by click reaction.
After a synthesis time of 130 min (S)-[18F]T1 was obtained with a radiochemical yield (non-decay corrected) of 4.3 ± 1.3%, a radiochemical purity of > 99% and a molar activity of > 158 GBq/µmol. The brain uptake and the brain-to-blood ratio of (S)-[18F]T1 in mice at 30 min post injection were 2.02 (SUV) and 6.1, respectively.
According to an ex-vivo analysis, the tracer remained intact (> 99%) in brain. Only one major radiometabolite was detected in plasma and urine samples. In-vitro autoradiography on pig brain slices revealed binding of (S)-[18F]T1 to brain regions associated with the expression of α3β4 nAChRs, which could be reduced by the α3β4 nAChR selective drug AT-1001. These findings make (S)-[18F]T1 a potential tool for the non-invasive imaging of α3β4 nAChRs in the brain by PET.
Keywords: α3β4 Nicotinic acetylcholine receptor Click reaction Drug addiction Positron emission tomography [18F]-Radioligand (S)-[18F]T1 Radiofluorination Registration No. 25383 - Permalink

Thermally Induced Spin Transfer Torque on MgO-based magnetic tunnel junctions using microstrip based resonator
Cansever, H.; Fowley, C.; Narkowicz, R.; Kowalska, E.; Aleksandrov, Y.; Yildirim, O.; Titova, A.; Lenz, K.; Lindner, J.; Fassbender, J.; Deac, A. M.
Abstract: Magnetic tunnel junctions have been commonly used in spintronics applications, such as magnetic random access memory (M-RAM), spin transfer torque RAM (STT-RAM) and hard disc drive (HDD) because of high storage capacity. A spin polarized current flowing through a ferromagnetic layer can exert spin-transfer-torque (STT) on the local magnetization. When we apply thermal gradient across the junction we can induce what is called thermal spin transfer torque (T-STT). In this study, the microresonator FMR technique is used in order to analyze how the ferromagnetic resonance signal corresponding to the free layer of an in-plane MgO-based tunnel junction device is modified in the presence of a temperature gradients across the barrier. Details of resonator fabrication and preliminary measurements are presented. This work is supported by DFG-SPP1538.
Keywords: spin transfer torque, microresonator, thermal gradient
  • Lecture (Conference)
    DPG-Frühjahrstagung 2017, 19.-24.03.2017, Dresden, Germany
Registration No. 25376 - Permalink

Magnetic properties of HoFe₆Al₆ with a compensation point near absolute zero: A theoretical and experimental study
Sabdenov, C. K.; Davydova, M. D.; Zvezdin, K. A.; Zvezdin, A. K.; Andreev, A. V.; Gorbunov, D. I.; Tereshina, E. A.; Skourski, Y.; Sebek, J.; Tereshina, I. S.
Abstract: Ferrimagnet HoFe6Al6 (tetragonal ThMn12-type crystal structure) has a compensation point for the Ho and Fe magnetic sublattices at a temperature close to absolute zero. The experimental study was carried out in fields up to 60 T. H-T phase diagrams and a full magnetization process along the principal crystallographic directions of a single-crystalline sample are obtained theoretically by using a model of a f-d ferrimagnet with two anisotropic sublattices, coupled by weak exchange interaction. The two first-order phase transitions, found experimentally along the [110] and [100] axes, were explained theoretically. The transition along the [110] direction occurs between noncollinear and collinear phases, it starts at the compensation point and ends at a tricritical point around 60 T. The transition along the [100] direction goes also from the point of compensation to the point of the liquid-vapor type at 40 T. This transition was shown to occur between two distinct noncollinear phases. The crucial role of the strong rare-earth anisotropy for the positions of the obtained critical points was revealed. Registration No. 25374 - Permalink

Uniaxial-stress tuned large magnetic-shape-memory effect in Ni-Co-Mn-Sb Heusler alloys
Salazar Mejia, C.; Küchler, R.; Nayak, A. K.; Felser, C.; Nicklas, M.
Abstract: Combined strain and magnetization measurements on the Heusler shape-memory alloys Ni45Co5Mn38Sb12 and Ni44Co6Mn38Sb12 give evidence for strong magneto-structural coupling. The sample length changes up to 1% at the martensitic transformation, between a ferromagnetic, austenitic phase at high temperatures and a weakly magnetic, low-symmetry martensitic phase at lower temperatures. Under moderate uniaxial stress, the change in the sample length increases to and saturates at about 3%, pointing to stabilization of a single martensitic variant. A reverse martensitic transformation can also be induced by applying magnetic field: we find that within the temperature range of thermal hysteresis of the martensitic transformation, applying a field can induce a metastable expansion of the sample, while at slightly lower temperatures, the field response is reversible. These findings provide key information for future use of Ni(Co)-Mn-Sb-based Heusler compounds in, e.g., actuators and mechanical switches. Registration No. 25373 - Permalink

Analysis of the exclusive final state npe+e in quasi-free np reaction
Adamczewski-Musch, J.; Arnold, O.; Atomssa, E. T.; Behnke, C.; Berger-Chen, J. C.; Biernat, J.; Blanco, A.; Blume, C.; Böhmer, M.; Bordalo, P.; Chernenko, S.; Deveaux, C.; Dreyer, J.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Franco, C.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gill, K.; Golubeva, M.; Guber, F.; Gumberidze, M.; Harabasz, S.; Hennino, T.; Hlavac, S.; Höhne, C.; Holzmann, R.; Ierusalimov, A.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Kardan, B.; Koenig, I.; Koenig, W.; Kolb, B. W.; Korcyl, G.; Kornakov, G.; Kotte, R.; Krása, A.; Krebs, E.; Kuc, H.; Kugler, A.; Kunz, T.; Kurepin, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Lorenz, M.; Mahmoud, T.; Maier, L.; Maurus, S.; Mangiarotti, A.; Markert, J.; Metag, V.; Michel, J.; Morozov, S.; Müntz, C.; Münzer, R.; Naumann, L.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Petousis, V.; Pietraszko, J.; Przygoda, W.; Ramos, S.; Ramstein, B.; Rehnisch, L.; Reshetin, A.; Rost, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schmidt-Sommerfeld, K.; Schuldes, H.; Sellheim, P.; Siebenson, J.; Silva, L.; Sobolev, Y. G.; Spataro, S.; Ströbele, H.; Stroth, J.; Strzempek, P.; Sturm, C.; Svoboda, O.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Wendisch, C.; Wirth, J.; Zanevsky, Y.; Zumbruch, P.
Abstract: We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/u inpinging on a liquid hydrogen target. Our measurements with HADES confirm a significant excess of e+e− pairs above the π0 mass in the exclusive channel dp→npe+e−(pspect) as compared to the exclusive channel ppe+e− measured in proton-proton collisions at the same energy. That excess points to different bremsstrahlung production mechanisms. Two models were evaluated for the role of the charged pion exchange between nucleons and double-Δ excitation combined with intermediate ρ-meson production. Differential cross sections as a function of the e+e− invariant mass and of the angles of the virtual photon, proton and electrons provide valuable constraints and encourage further investigations on both experimental and theoretical side.

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Registration No. 25372 - Permalink

Influence of FeII on the retention mechanisms of NpO2+ by montmorillonite
Marques Fernandes, M.; Scheinost, A. C.; Baeyens, B.
Abstract: For the safety case for high-level radioactive waste repositories, redox phenomena play an important role for radionuclide retention. In the near field, the corrosion of steel canisters will release large amounts of ferrous iron and in addition produce H2 with a strong influence on the “in situ” redox potential (Eh). This combination of high {FeII} and low (Eh) in the interstitial waters of the engineered barrier system (bentonite, consisting predominantly of the phyllosilicate montmorillonite) is expected to have a strong impact on the retention of redox sensitive radionuclides like Tc, Se and the early actinides U, Np, and Pu, all of high relevance for safety of radioactive waste repositories.
In the present work we investigated by X-ray absorption spectroscopy (XAS) the influence of FeII on the retention of the redox sensitive NpV by montmorillonite. Since natural montmorillonite always contains structural Fe, we made use of a synthetic iron-free montmorillonite (IFM) [1] to discriminate the influence of sorbed FeII from that of structural iron. For FeII loadings below 40 mmol·kg-1, sorbed Fe had no effect, with Np showing the typical sorption behaviour of the pentavalent aquo-ion by forming comparatively weak inner-sphere sorption complexes at the edge sites of montmorillonite. For FeIIsorb above 40 mmol·kg-1, however, we observed an increasing reduction of NpV to NpIV, with a complete reduction for FeIIsorb  80 mmol·kg-1. In spite of the low solubility of NpO2, we did not observe precipitation of this phase, but formation of mononuclear innersphere sorption complexes (Fig. 1-A). The influence of structural FeII was investigated using citrate-dithionite–bicarbonate (CDB) reduced SWy montmorillonite (i.e. structural FeIII fully reduced to FeII). XAS showed that Np is present only as NpIV on the clay surface (Fig. 1-B).
Our study demonstrates that both structural and adsorbed FeII on montmorillonite lead to a surface mediated reduction of NpV, thereby increasing the retention by more than two orders of magnitude.
Keywords: montmorillonite iron neptunium EXAFS XANES sorption modeling
  • Lecture (Conference)
    AnXAS 2017: 8th Workshop on Speciation, Techniques, and Facilities for Radioactive Materials at Synchrotron Light Sources, 11.-13.04.2017, Oxford, United Kingdom
Registration No. 25366 - Permalink

Bubble Generation by Solid Membrane Spargers for Activated Sludge Wastewater Treatment Application
Mohseni, E.; Herrmann-Heber, R.; Reinecke, S.; Hampel, U.
Abstract: Current endeavor experimentally studies the initial bubble size distribution from the stainless steel diffusers and needle spargers with very fine orifice diameters range from 30 to 200 µm. To evaluate the performance of these spargers, the results where compared with four industrial rubber membranes in terms of Sauter mean diameter, pressure drop and frequency of bubble formation. Outcomes of current study showed that, the stainless steel perforated plates impose their superiority over the flexible membranes, by generating 50% smaller bubbles, and 70% higher bubble generation frequency at 60% less pressure drop. Moreover, the perforated stainless steel plates are able to produce bubble sizes in the same class as needles at 40% of the pressure drop caused by needle spargers and average of 60% higher bubble generation frequency.
Keywords: Bubble Generation, Activated Sludge, Aeration, Biological Wastewater Treatment, Multiphase Flow
  • Lecture (Conference)
    The 9th Eastern European Young Water Professionals Conference, 24.-27.05.2017, Budapest, Hungary
Registration No. 25361 - Permalink

Terahertz spectroscopy of semiconductor nanostructures with a free-electron laser
Schneider, H.
Abstract: In this talk I will present our recent experimental investigations on carrier dynamics in graphene studied via nonlinear laser spectroscopy, on time-resolved photoluminescence dynamics of single InAs/GaAs quantum dots under pulsed inter-sublevel excitation, and on sub-diffraction limited terahertz imaging by a GaAs-based superlens studied by scattering near-field optical microscopy. The experiments have been carried out using the mid-infrared/terahertz free-electron laser facility FELBE in Dresden, Germany.
Keywords: terahertz, free-electron laser, graphene, quantum dots, superlens
  • Lecture (others)
    Seminarvortrag, University of Wollongong, 02.03.2017, Wollongong, Australia
Registration No. 25360 - Permalink

Chancen und Grenzen einer Circular Economy
Reuter, M. A.
  • Invited lecture (Conferences)
    Tag der Metallurgie, 02.-04.03.2016, Goslar, Deutschland
  • Invited lecture (Conferences)
    Berliner Recycling- und Rohstoffkonferenz, 06.-07.03.2016, Berlin, Deutschland

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Registration No. 25359 - Permalink

THz spectroscopy of solids with a free electron laser
Helm, M.
Abstract: THz spectroscopy of solids with a free electron laser
Keywords: terahertz, free electron laser, spectroscopy
  • Invited lecture (Conferences)
    2nd German THz Conference, 29.-31.03.2017, Bochum, Germany
Registration No. 25356 - Permalink

Modified DTPA ligand systems for simplified trivalent actinide-lanthanide separations based on the TALSPEAK process
Jones, J. E.; Langford, M. H.; Geist, A.; Panak, P. J.; Kaden, P.; Adam, C.; Adam, N.; Sharrad, C. A.; Martin, L.; Natrajan, L. S.
Abstract: The necessity to reprocess spent nuclear fuel has arisen from increasing volumes of highly active and long-lived radionuclides associated with nuclear fission alongside increasing environmental impact concerns. In particular, one major challenge is the separation of the long-lived trivalent minor actinides (here, AmIII and CmIII) from the trivalent lanthanides in order to allow the future transmutation of the actinides into shorter lived radionuclides for the purpose of reducing the long-term radiotoxicity of the waste and the volume build up in storage. There are currently a number of different processes under development world-wide, all of which rely on the coordination chemistry and selective extraction of the minor actinides from the trivalent lanthanides using solvent partitioning. Of these, The TALSPEAK process (Trivalent Actinide Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexations) has showed great promise in separating the trivalent lanthanides from the minor actinides. The process uses DTPA (diethylenetriamine pentaacetic acid) as the chelating holdback reagent, HDEHP (bis-2-ethylhexyl phosphoric acid) as the extracting ligand and lactic acid as the buffer to prevent precipitation of DTPA that occurs at below pH 3.6. However, despite the considerable separation factors obtainable, and the fact the process exhibits promising radiolysis resistance, the process operates at sub optimal pH values. To overcome these limitations, we have developed a family of DTPA-amino acid conjugates that operate under TALSPEAK-like conditions over a much lower pH range of 1.5-2.5. Additionally, these ligands show comparable selectivity to the TALSPEAK process and are also relatively resistant to radiolysis. We will discuss the coordination chemistry of these ligands with the lanthanides and minor actinides using a combination of luminescence and NMR spectroscopies.
Keywords: DTPA, amino acids, actinides(III), lanthanides(III)
  • Lecture (Conference)
    253rd ACS National Meeting & Exposition, 02.-06.04.2017, San Francisco, CA, United States
Registration No. 25350 - Permalink

Assessment of thermal phenomena in Li||Bi liquid metal batteries through analytical and numerical models
Personnettaz, P.
Abstract: Liquid Metal Batteries (LMBs) are a promising electrical energy storage technology, built as a stable density stratification of two liquid metals separated by a molten salt. Their operation has been proved only for small prototypes, in order to transfer it to the industrial scale full knowledge of the different phenomena occurring in LMBs is required. In this work, done at Helmholtz-Zentrum Dresden-Rossendorf, we focus our attention on the thermal phenomena that appear inside Li||Bi LMBs . The system is first analyzed in the framework of the electrochemistry, a simple voltage model is developed and the heat generation terms are estimated. The geometrical and operating parameters are fully defined from multi-physics considerations. Then LMBs are studied with the continuum mechanics approach and all possible thermal phenomena are discussed. In the hypothesis of pure heat conduction, the first assessment of the effects of the reversible heat generation was done. Moreover the multiphase solver multiphaseInterFOAM is extended in order to take into account the thermal convection inside the cell. The results of our solver are compared to the one of a pseudo-spectral code. Finally some simulation results of thermal convection in LMBs are proposed.
  • Master thesis
    Politecnico di Torino, 2017
Registration No. 25349 - Permalink

Biosynthesis of magnetic nanoparticles by human mesenchymal stem cells following transfection with the magnetotactic bacterial gene mms6
Elfick, A.; Rischitor, G.; Mouras, R.; Azfer, A.; Lungaro, L.; Uhlarz, M.; Herrmannsdörfer, T.; Lucocq, J.; Gamal, W.; Bagnaninchi, P.; Semple, S.; Salter, D. M.
Abstract: The use of stem cells to support tissue repair is facilitated by loading of the therapeutic cells with magnetic nanoparticles (MNPs) enabling magnetic tracking and targeting. Current methods for magnetizing cells use artificial MNPs and have disadvantages of variable uptake, cellular cytotoxicity and loss of nanoparticles on cell division. Here we demonstrate a transgenic approach to magnetize human mesenchymal stem cells (MSCs). MSCs are genetically modified by transfection with the mms6 gene derived from Magnetospirillum magneticum AMB-1, a magnetotactic bacterium that synthesises single-magnetic domain crystals which are incorporated into magnetosomes. Following transfection of MSCs with the mms6 gene there is bio-assimilated synthesis of intracytoplasmic magnetic nanoparticles which can be imaged by MR and which have no deleterious effects on cell proliferation, migration or differentiation. The assimilation of magnetic nanoparticle synthesis into mammalian cells creates a real and compelling, cytocompatible, alternative to exogenous administration of MNPs.

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Registration No. 25341 - Permalink

Ion Irradiation Induced Cobalt/Cobalt Oxide Heterostructures: From Materials to Devices
Hilliard, D.; Yildirim, O.; Fowley, C.; Kanth Arekapudi, S. S. P. K.; Cansever, H.; Böttger, R.; Hlawacek, G.; Hellwig, O.; Lindner, J.; Fassbender, J.; Deac, A. M.; Perzanowski, M.
Abstract: Spintronic devices are often patterned from continuous films into micro- or nanostructures. Fabrication of those nano-devices is self-limited and depends on the lateral resolution of the chosen fabrication method. Ion irradiation offers an alternative route to introduce smaller magnetic patterns limited by the size of the ion beam. Irradiation of oxide materials can cause chemical reduction and lead to the local formation of metallic species. By using the oxide family of ferromagnets (e.g., Fe, Ni and Co), reduction leads to the formation of ferromagnetic and conducting volumes limited by the size of the ion irradiated area that are embedded into a non-magnetic and insulating matrix. On the other hand, the physical mechanism behind ion irradiation-induced oxide reduction could not be explained. Therefore, our studies focus on ion (H, He, Ne, O) irradiated cobalt-oxide (CoO or Co3O4) systems in order to explain the physics behind the process. Also, the knowledge is being exploited to tune exchange-bias direction, prepare nano contacts for synchronized spin torque oscillators, and to form topographically stabilized magnetic skyrmions.
Keywords: Cobalt oxide, Ion irradiation, Oxygen reduction, Ferromagnetic
  • Poster
    DPG-Frühjahrstagung (DPG Spring Meeting), 19.-24.03.2017, Dresden, Deutschland
Registration No. 25338 - Permalink

Ab initio thermodynamic study of proton conductivity in BaZrO3
Raja, N.; Murali, D.; Posselt, M.; Satyanarayana, S. V. M.
Abstract: BaZrO3 (BZO) is a potential candidate material for electrode in solid oxide fuel cells (SOFL) because of its excellent reported proton conductivity [1, 2]. It is suggested that presence of intrinsic point defects such as O vacancies act as sinks for O atoms produced upon hydrogenation of water molecule and promote proton conductivity. For this, the formation energy of O atom should be lower and its migration should be suppressed [3]. Since these materials are used at high temperature, it is very important to consider effects of phonons on the defect chemistry [4, 5, 6]. In this work, first, we identify thermodynamically favorable conditions for the formation of BZO by free energy calculations of bulk phases using Density Functional Theory. Next, we study the free energy of formation of both neutral and charged O vacancies of stable BZO phase and discuss significance of these results for experimental growth conditions. Initial results show that phonon contributions to free formation energy of charged vacancy is significantly high compared to neutral vacancy due to large lattice distortion and negative formation entropy for charged vacancy. Studies also show that acceptor doping both at A and B site lowers the formation energy of O vacancy in the vicinity of dopant atoms resulting in increase of proton conductivity [7, 8]. In order to understand the mechanism of this enhancement, we study the free energy of formation of O clusters in reducing conductions for acceptor doping at A and B sites.

References

[1] K. D. Kreuer, Annu. Rev. Mater. Res. 2003, 33:333–59.
[2] K. D. Kreuer, ed. T. Ishihara, Springer, 2009, pp. 261–271.
[3] Emile B´ evillon, Guilhem Dezanneau, and Gr´ egory Geneste, Physical Review B 2011, 83,
174101.
[4] Jessica Hermet, Francois Bottin, Guilhem Dezanneau, and Gregory Geneste Physical Review
B 2012, 85, 205137.
[5] Denis Gryaznov, Evgeny Blokhin, Alexandre Sorokine, Eugene A. Kotomin, Robert A.
Evarestov, Annette Bussmann-Holder, and Joachim Maier J. Phys. Chem. C 2013, 117,
13776−13784.
[6] Tor S. Bjørheim, Marco Arrigoni, Denis Gryaznov, Eugene Kotomin and Joachim Maier
Phys. Chem. Chem. Phys. 2015, 17, 20765.
[7] Marten E. Bjorketun, Per G. Sundell, and Goran Wahnstrom Physical Review B, 2007,
76, 054307.
[8] Andreas Løken, Sarmad W. Saeed, Marit N. Getz, Xin Liu and Tor S. Bjørheim, J. Mater.
Chem. A, 2016, 4, 9229.
Keywords: DFT, proton conductivity, solid oxide fuel cells
  • Lecture (Conference)
    International Conference on Advances in Functional Materials, 06.-08.01.2017, Chennai, Madras, India
Registration No. 25336 - Permalink

Role of Oxygen Vacancy on the Hydrophobic Behavior of TiO2 Nanorods on Chemically Etched Si Pyramids
Saini, C. P.; Barman, A.; Das, D.; Satpati, B.; Bhattacharyya, S. R.; Kanjilal, D.; Ponomaryov, A.; Zvyagin, S.; Kanjilal, A.
Abstract: Oxygen vacancy (OV) controlled hydrophobicity of self-assembled TiO2 nanorods (NRs) on chemically etched Si pyramids is investigated by irradiating with 50 keV Ar-ions at room temperature. Apparent contact angle (CA) is found to increase from 122° to 141° up to a fluence of 1 × 1015 ions/cm2, followed by a gradual reduction to 130° at 1 × 1017 ions/cm2. However, the drop in apparent CA is found to be associated with the decrease in fractional surface area via transformation of NRs to an amorphous layer above 1 × 1015 ions/cm2, though it is still higher than that of as-grown one. Detailed X-ray photoelectron spectroscopy and electron paramagnetic resonance measurements suggest that the control of hydrophobic behavior is related to the suppression of surface free energy via migration of OVs into the voids in TiOx layers. Registration No. 25331 - Permalink

Eco-efficiency indicator framework implemented in the metallurgical industry: part 2-a case study from the copper industry
Reuter, M. A.; Ronnlund, I.; Horn, S.; Aho, J.; Aho, M.; Paallysaho, M.; Ylimaki, L.; Pursula, T.
Abstract: Purpose Sustainability differentiation has become an important issue for companies throughout the value chain. There is thus a need for detailed and credible analyses, which show the current status and point out where improvements can be done and how. The study describes how a comprehensive product-centric eco-efficiency indicator framework can be used to evaluate, benchmark, and communicate the sustainability of a copper production value chain. The indicator framework, together with the suggested data collection and simulation methods, aims at evaluating the whole system, while still enabling a focus on scopes of different width. The status of the environment, current production technologies, locationspecific and process-specific issues all play a role in achieving sustainable development.
Methods Copper cathode production from copper ore was chosen to exemplify the developed framework. Data sets from a simulation tool were used when available and LCI databases and LCA software were utilized for the remaining steps. The value chain is analyzed and the benchmark for each indicator built according to the new Gaia Refiner indicator framework. This method enables analysis of specific production steps with a higher degree of accuracy.
Results and discussion The case study shows how some important environmental sustainability issues in copper production can be analyzed and benchmarked within a product group. Benchmark data is collected and used in the analysis for the selected system scope. Data availability is still an issue and the example shows which areas require more information in this context so that products and value chains can be benchmarked in the future on a more consistent basis. The energy mix, chemical use, and land use contribute to potential environmental sustainability risks within the product benchmarking group, while emissions control shows competitive environmental sustainability advantages for the case study.
Conclusions The methodology is shown to work well in highlighting the sustainability advantages and risks of value chains in copper production with the selected system scope in a visualmanner through the Sustainability Indicator "Flower" The importance of a baseline is clear.
The effect of the metal ore grade on the results shows that the scalability of the analysis system is very important. Scaling the system scope up will show the differences in varying value chains and scaling the system scope down will show efficiency differences between more similar value chains, thus visualizing where innovation has the biggest impact.
Keywords: Benchmarking, Circular economy, Eco-efficiency, Footprint, Indicator, Metallurgy, Process and system simulation, Resource efficiency, Sustainability Registration No. 25329 - Permalink

Ultra-robust high-field magnetization plateau and supersolidity in bond-frustrated MnCr2S4
Tsurkan, V.; Zherlitsyn, S.; Prodan, L.; Felea, V.; Cong, P. T.; Skourski, Y.; Wang, Z.; Deisenhofer, J.; Krug Von Nidda, H.-A.; Wosnitza, J.; Loidl, A.
Abstract: Frustrated magnets provide a promising avenue for realizing exotic quantum states of matter, such as spin liquids and spin ice or complex spin molecules. Under an external magnetic field, frustrated magnets can exhibit fractional magnetization plateaus related to definite spin patterns stabilized by field-induced lattice distortions. Magnetization and ultrasound experiments in MnCr2S4 up to 60 T reveal two fascinating features: an extremely robust magnetization plateau with an unusual spin structure and two intermediate phases, indicating possible realizations of supersolid phases. The magnetization plateau characterizes fully polarized chromium moments, without any contributions from manganese spins. At 40 T, the middle of the plateau, a regime evolves, where sound waves propagate almost without dissipation. The external magnetic field exactly compensates the Cr–Mn exchange field and decouples Mn and Cr sublattices. In analogy to predictions of quantum lattice-gas models, the changes of the spin order of the manganese ions at the phase boundaries of the magnetization plateau are interpreted as transitions to supersolid phases.

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Registration No. 25322 - Permalink

Sulphide vein mineralization of the shallow eastern stock work zone and its genetic relation to the massive sulphide mineralization at the Sakatti Cu-Ni-PGE deposit, Finland
Fröhlich, F.; Gutzmer, J.; Siikaluoma, J.; Osbahr, I.
Abstract: he Sakatti Cu-Ni-PGE deposit is situated in northern Finland and was discovered by Anglo American Exploration in 2009 (Halkoaho 2014). It is said to be one of the most significant discoveries in Finland for more than a generation (Maier et al. 2015). The mineralization comprises massive, disseminated and vein sulphides. A stockwork is formed by the sulphide veins, which contains exceptionally high grades of Cu, platinum-group elements (PGE) and Au in the shallow eastern part of the deposit. In contrast to the massive and disseminated sulphide mineralization, the mineralogy, mineral paragenesis and petrography of the stockwork zone is relatively poorly uninvestigated, and this study aimed at increasing knowledge of it.
Traditional light microscopy and automated scanning electron microscope (SEM)- based image analyses using a mineral liberation analyser (MLA) on 20 samples from 11 drill holes revealed a classic magmatic sulphide assemblage of chalcopyrite ± pyrrhotite, pentlandite and pyrite. Additionally, 1,133 platinum-group mineral (PGM) particles belonging almost exclusively to the moncheite (PtTe2) – merenskyite (PdTe2) – melonite (NiTe2) solid solution series were discovered (Fig. 1 a, b). Notably, almost two-thirds of the PGE-bearing phases consist of melonite. Some of the PGM particles contain inclusions of electrum (AgAu2) and muthmannite (AgAuTe2), which possess an average of 0.25 wt% Au. For the first time at Sakatti, one particle of irarsite (IrAsS) was encountered. The PGM display a trimodal particle area distribution, which is a result of an increasing mineralogical complexity of the particles relative to their sizes. Most of the PGM are hosted in inclusions (76%) (mainly in chalcopyrite), whereas minor amounts are located at grain boundaries (19%) and in cracks (5%).
An enrichment of PPGE relative to IPGE was recognized in the sulphide veins, which is in line with data on the massive and disseminated sulphide mineralization at Sakatti (Ahvenjärvi 2015). However, the di erence between maximum and minimum enrichments is more pronounced for the sulphide veins.
Element ratios calculated from geochemical data obtained by ICP-MS/OE analyses and displayed in various plots (e.g. Cu/Ir vs. Ni/Pd, Rh vs. Rh/Cu (Fig. 2)) indicate that the Cu-rich sulphide veins represent the magmatic crystallization products of a highly fractionated Cu-rich sulphide liquid enriched in Pt, Pd, Au, Ag, As, Bi, Pb, Se, Te and Zn, which separated from monosulphide solid solution (mss). Intermediate solid solution (iss) solidi ed from the Cu-rich sulphide liquid, exsolving chalcopyrite at <550 °C. Simultaneously, small volumes of intercumulus residual melt mainly contained the precious metals Bi and Te due to their incompatibility in iss. Solitary and composite PGM, as well as Au minerals crystallized rst from the residual melt (<600 °C), followed by a succession of various Bi, Ag and Pb tellurides (~540 °C), and nally sphalerite (ZnS) and galena (PbS). However, melonite crystallized in two stages: as large, solitary grains directly exsolved from Ni-bearing iss (~600 °C) shortly after the formation of moncheite and merenskyite from the residual melt, and during subsolidus exsolution (<600 °C) with precipitation on the surfaces of earlier formed PGM. Finally, slight remobilization of the PGM occurred at temperatures <300 °C, veri ed by minor amounts of Cl-bearing minerals and ragged particle shapes. Surprisingly, the geochemical data (Fig. 2), petrography and genetic concept of the sulphide veins at Sakatti proved to be very similar to the Cu-rich footwall veins at the McCreedy East deposit in Sudbury (Canada) (Naldrett et al. 1999, Dare et al. 2014).
  • Contribution to proceedings
    3rd Finnish National Colloquium of Geosciences, 15.-16.03.2017, Espoo, Finland
    Abstract Book, 3rd Finnish National Colloquium of Geosciences, Espoo: Geological Survey of Finland, ISBN 978-952-217-376-8, 26-27
  • Lecture (Conference)
    3rd Finnish National Colloquium of Geosciences, 15.-16.03.2017, Espoo, Finland
Registration No. 25320 - Permalink

Multimetallic Hierarchical Aerogels: Shape Engineering of the Building Blocks for Efficient Electrocatalysis
Cai, B.; Dianat, A.; Hübner, R.; Liu, W.; Wen, D.; Benad, A.; Sonntag, L.; Gemming, T.; Cuniberti, G.; Eychmüller, A.
Abstract: A new class of multimetallic hierarchical aerogels composed entirely of interconnected Ni-PdxPty nano-building-blocks with in situ engineered morphologies and compositions is demonstrated. The underlying mechanism of the galvanic shape-engineering is elucidated in terms of nanowelding of intermediate nanoparticles. The hierarchical aerogels integrate two levels of porous structures, leading to improved electrocatalysis performance. Registration No. 25315 - Permalink

Entropy Evolution in the Magnetic Phases of Partially Frustrated CePdAl
Lucas, S.; Grube, K.; Huang, C.-L.; Sakai, A.; Wunderlich, S.; Green, E. L.; Wosnitza, J.; Fritsch, V.; Gegenwart, P.; Stockert, O.
Abstract: In the heavy-fermion metal CePdAl, long-range antiferromagnetic order coexists with geometric frustration of one-third of the Ce moments. At low temperatures, the Kondo effect tends to screen the frustrated moments. We use magnetic fields B to suppress the Kondo screening and study the magnetic phase diagram and the evolution of the entropy with B employing thermodynamic probes. We estimate the frustration by introducing a definition of the frustration parameter based on the enhanced entropy, a fundamental feature of frustrated systems. In the field range where the Kondo screening is suppressed, the liberated moments tend to maximize the magnetic entropy and strongly enhance the frustration. Based on our experiments, this field range may be a promising candidate to search for a quantum spin liquid. Registration No. 25310 - Permalink

Analytical balance-based Faraday magnetometer
Riminucci, A.; Uhlarz, M.; de Santis, R.; Herrmannsdörfer, T.
Abstract: We introduce a Faraday magnetometer based on an analytical balance in which we were able to apply magnetic fields up to 0.14 T. We calibrated it with a 1mm Ni sphere previously characterized in a superconducting quantum interference device (SQUID) magnetometer. The proposed magnetometer reached a theoretical sensitivity of 3x 10-8 Am2. We demonstrated its operation on magnetic composite scaffolds made of poly(e-caprolactone)/iron-doped hydroxyapatite. To confirm the validity of the method, we measured the same scaffold properties in a SQUID magnetometer. The agreement between the two measurements was within 5% at 0.127 T and 12% at 24mT. With the addition, for a small cost, of a permanent magnet and computer controlled linear translators, we were thus able to assemble a Faraday magnetometer based on an analytical balance, which is a virtually ubiquitous instrument. This will make simple but effective magnetometry easily accessible to most laboratories, in particular, to life sciences ones, which are increasingly interested in magnetic materials. Registration No. 25309 - Permalink

Measurements with neutrons and photons at nELBE
Beyer, R.; Dietz, M.; Frotscher, A.; Görres, J.; Junghans, A. R.; Kögler, T.; Nolte, R.; Oberlack, U.; Pirovano, E.; Plompen, A.; Reifarth, R.; Schwengner, R.; Urlaß, S.; Wagner, A.
Abstract: The neutron time-of-flight facility nELBE at Helmholtz-Zentrum Dresden-Rossendorf features the first photo-neutron source at a superconducting electron accelerator, which provides a very precise time structure, high repetition rate and favorable background conditions due to the low instantaneous flux and the absence of any moderating materials. The neutron energy spectrum ranges from about 100 keV up to 10 MeV. The resulting very flexible beam properties at nELBE enable a broad range of nuclear physics experiments. Examples for the versatility of nELBE will be presented: Total neutron cross section measurements to look for unknown nuclear levels relevant for the astrophysical s-process, determination of the photon angular distribution after inelastic neutron scattering, determination of the detector response of a Dark Matter detector based on liquid Xe, or determination of the neutron induced fission cross section of 242Pu.
Keywords: nELBE, neutron time-of-flight, neutron inelastic scattering, neutron transmission, neutron induced fission, dark matter, liquid Xe
  • Lecture (Conference)
    81. Jahrestagung der DPG und DPG-Frühjahrstagung, 27.-31.03.2017, Münster, Deutschland
Registration No. 25304 - Permalink

In situ RBS, Raman spectroscopy, and ellipsometry study of nickel-catalyzed graphitization of thin amorphous carbon films
Janke, D.; Wenisch, R.; Lungwitz, F.; Munnik, F.; Hulman, M.; Gemming, S.; Rafaja, D.; Krause, M.
Abstract: Metal-induced crystallization (MIC) with and without layer exchange (LE) is a method to decrease the crystallization temperature of amorphous group 14 elements by up to several hundred degrees. In situ experiments are expected to provide new insights into thin film evolution and elementary process steps of MIC and to improve existing models of this type of phase transformation. In this contribution in situ Rutherford backscattering spectrometry (RBS), Raman spectroscopy and spectroscopic ellipsometry studies were performed during annealing of amorphous carbon/nickel (a-C/Ni) layer stacks at temperatures up to 750°C.
LE was observed independently of the initial stacking sequence, while transformation rate and temperature differ significantly. The positions of the G, D and 2D Raman lines as well as the I(D)/I(G) ratio changed during the LE process. These were assigned in agreement with the Three-Stage-Model [1], confirming the transformation of a-C to nc-graphite. In situ RBS measurements demonstrated an opposite shift of the C- and Ni- related backscattering energies, proving that LE and graphitization occur simultaneously.
[1] Ferrari et al., Phys. Rev. B 61 (2000) 14095
Keywords: Metal-induced crystallization in situ RBS in situ Raman spectroscopy
  • Poster
    International Winterschool on Electronic Properties of Novel Materials, 04.-11.03.2017, Kirchberg in Tirol, Österreich
Registration No. 25301 - Permalink

FDG uptake in normal tissues assessed by PET during treatment has prognostic value for treatment results in head and neck squamous cell carcinomas undergoing radiochemotherapy
Zschaeck, S.; Löck, S.; Leger, S.; Haase, R.; Bandurska-Luque, A.; Appold, S.; Kotzerke, J.; Zips, D.; Richter, C.; Gudziol, V.; Schreiber, A.; Zöphel, K.; Baumann, M.; Krause, M.
Abstract: Background and purpose: Pronounced early side effects have been suggested to be a positive prognostic factor in patients undergoing chemo-radio-therapy (CRT) for head and neck squamous cell carcinomas (HNSCC). We assessed the utility of positron emission tomography (PET) during treatment to analyze the correlation of 18F-fluorodeoxyglucose (FDG) uptake in off target structures within the irradiated volume with outcome.
Material and methods: Two independent cohorts of patients with locally advanced HNSCC, both treated within prospective clinical imaging trials with curatively intended CRT were retrospectively analyzed.
The exploratory cohort included 50, the independent validation cohort 26 patients. Uptake of FDG in mucosa and submucosal soft tissues (MST) as well as in other structures was assessed at week 4 during treatment. Considered endpoints were local tumor control (LC) and overall survival (OS). The prognostic value of FDG uptake on the endpoints was measured by the concordance index (ci) using univariate and multivariate Cox regression analyses based on the continuous variables of the exploratory cohort.
Results: In the exploratory cohort FDG uptake in MST was prognostic for LC (hazard ratio HR = 0.23, p = 0.025) and OS (HR = 0.30, p = 0.003) in univariate analyses. These findings remained significant upon multivariate testing (LC HR = 0.14, p = 0.011; OS HR = 0.20, p = 0.001) and were confirmed in the validation cohort for LC (HR = 0.15, p = 0.034) and OS (HR = 0.17, p = 0.003). Also the SUVmean threshold of MST that was generated within the exploratory cohort (2.375) yielded significant differences in OS (p = 0.006) and a statistical trend for LC (p = 0.078) when applied to the validation cohort.
Conclusions: FDG uptake in normal tissues within the irradiated volume measured by PET during treatment has significant prognostic value in HNSCC. This effect may potentially be of use for personalized treatment adaptation.

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  • Secondary publication expected from 13.01.2018
Registration No. 25298 - Permalink

Recent and present activities in THEREDA
Moog, H. C.; Altmaier, M.; Brendler, V.; Bok, F.; Gaona, X.; Marquardt, C.; Richter, A.; Scharge, T.; Thoenen, T.; Voigt, W.
Abstract: INTRODUCTION
THEREDA is the acronym for “Thermodynamic Reference Database”, a multi-institutional, national joint project to create a mutually accepted database for the geochemical modeling of solubilities in the near field of an underground repository for high-level waste in a rock salt formation (Moog et al. 2015).
As of April 2010 THEREDA became operative in the world wide web, and since 30th of June 2011 ready-to-use parameterfiles for EQ3/6, Geochemist’s Workbench, PHREEQC, and ChemApp are released. During the following years the team issued altogether eleven data releases. Each release covers data for particular subsystems only.
RECENT ACTIVITIES
Data releases
During the last two years three data releases were issued. Each release was qualified and documented with test calculations. Apart from ChemApp the releases are accompanied by code-specific scripts which enable the user to reproduce our calculations.
R-09 covered the systems
• U(IV) – (Na, K) – HCO3 – H2O
• U(IV) – Na – Cl – H2O
• U(VI) – (Na, K, Ca) – Cl – H2O
R-10 covered the systems
• Na - Cl - Tc(IV) / Tc(VII) - OH,
• Mg - Cl - Tc(IV) - OH,
• Ca - Cl - Tc(IV) - OH
R-11 covered the systems
• Sr – (Na, K, Mg, Ca) – Cl – H2O
• Sr - Na – SO4 – H2O
R-10 was the first release to cover a redox reaction. Our efforts to produce parameter files for different codes which deliver the same result posed unexpected difficulties and revealed differences on how the different codes tackle redox transitions.
Extension of internal calculation
THEREDA features a system of internal calculations of dependent data from independent data (the latter ones directly entered). It has been extended to provide for temperature extrapolations from standard reaction data and for the calculation of the latter from temperature functions of equilibrium constants of standard molar Gibbs free enthalpies of reaction.
PRESENT ACTIVITIES
Data releases
The following data releases are in preparation and have priority for 2017.
• Solubility of oxygen in pure water and high saline solutions
• Na, K – Cl,SO4 – (PO43-, HPO42-, H2PO4-) –H2O (binary, ternary, and some quaternary systems tested)
• This will lead to an upgrade of R-09 covering uranium solubility in phosphate bearing solutions
• Merge of R-01 (Na, K, Mg, Ca – Cl, SO4 – H2O polythermal) and R-03 (Na, K, Mg, Ca – Cl, SO4 – HCO3/CO2(g) – H2O 298.15K only) with an upgrade of the latter for elevated temperatures.
As a side product, the release on the oxygen solubilities will lead to a re-evaluation of logK-values for the reactions
2H2O(l) ⇌ O2(aq) + 2H2(g)
2H2O(l) ⇌ O2(g) + 2H2(g)
REFERENCES
1. H. C. MOOG et al., Disposal of Nuclear Waste in Host Rock formations featuring high-saline solutions - Implementation of a Thermodynamic Reference Database (THEREDA). Appl. Geochem. (55), 72-84 (2015). http://dx.doi.org/10.1016/j.apgeochem.2014.12.016
E. Yalçintaş et al., Thermodynamic description of Tc(IV) solubility and hydrolysis in dilute to concentrated NaCl, MgCl2 and CaCl2 solutions, Dalton Transactions (45), 8916-8936 (2016). -> [YAL/GAO2016]
2. J. B. Macaskill et al., Isopiestic measurements on aqueous Mixtures of Sodium Chloride and Strontium Chloride. J. Solution Chem. (7), 339-347 (1978). -> [MAC/WHI1978]
3. V. K. Filippov et al., Thermodynamics of phase equilibria in the potassium, strontium, sodium, chloride, water (K+,Sr2+|| Cl--H2O, Na+,Sr2+|| Cl--H2O and Na+,K+,Sr2+|| Cl--H2O) systems at 25°, Russ. J. Gen. Chem. (60), 427-431 (1990). -> [FIL/FED1990]
4. J. A. Rard and D. G. Miller, Isopiestic determination of the osmotic and activity coefficients of aqueous mixtures of sodium chloride and strontium chloride at 25° C, J. Chem. Eng. Data (27), 342-346 (1982). -> [RAR/MIL1982b]
5. S. L. Clegg et al., Isopiestic Determination of the Osmotic and Activity Coefficients of NaCl + SrCl2 + H2O at 298.15 K and Representation with an Extended Ion-Interaction Model, J. Chem. Eng. Data (50), 1162-1170 (2005). -> [CLE/RAR2005]
6. M. Kydynov et al., Solubility in the quaternary system consisting of lithium, sodium and strontium chlorides and water at 25 °C, J. Appl. Chem. (London) (4), 736-739 (1969). -> [KYD/LOM1969]
Keywords: THEREDA, Thermodynamic Reference Database, Pitzer
  • Lecture (Conference)
    Actinide Brine Chemistry (ABC-Salt V Workshop 2017), 26.-28.03.2017, Ruidoso, USA
Registration No. 25287 - Permalink

Entwicklung und Validierung von Bildauswertealgorithmen zur Charakterisierung der Gas-Flüssigkeits-Strömung in Anstaupackungen
Litzka, A.
Abstract: Am Helmholtz-Zentrum Dresden Rossendorf wird die Fluiddynamik von Anstaupackungen untersucht, einer neuen Form von Einbauten für Trennkolonnen. Für die Auswertung der Messungen mithilfe der ultraschnellen Röntgentomographie werden Algorithmen benötigt, welche die Ermittlung der Phasenverteilung in den Packungen ermöglichen.
In dieser Arbeit wurde untersucht, ob dies mithilfe von Bildsegmentierung erfolgen kann. Die Segmentierung muss in Gas, Flüssigkeit und Titanblech erfolgen. Es wurden geeignete Messphantome erstellt, anhand derer die Implementierung der Algorithmen erfolgte. Für die Validierung der Ergebnisse wurden Referenzmessungen mit Röntgen-Mikrotomographie eingesetzt.
Aufgrund der mangelnden Bildqualität der rekonstruierten Daten ist zunächst nur Identifikation der Gasphase in den Phantomen möglich. Der Ansatz die Feststoffstruktur mithilfe der Referenzmessung lokalisieren zu können, scheiterte an einer Verzerrung der abgebildeten Geometrien durch die ultraschnelle Röntgentomographie infolge der Bildrekonstruktion.
Des Weiteren wurde versucht mithilfe einer Dekonvolution die Bildqualität zu verbessern und so die Voraussetzung für eine Segmentierung in drei Phasen zu schaffen. Im entfalteten Bild ist es für eine der drei Strömungsformen möglich, in lokalen Bereichen Schwellwerte für eine Segmentierung in drei Phasen zu ermitteln. Offen ist, ob sich dies auf die anderen Strömungsformen übertragen lässt und eine Optimierung der Auswertealgorithmen eine ausreichende Genauigkeit der Anteilsbestimmung ermöglicht.
  • Study thesis
    TU Dresden, 2017
    Mentor: J. Sohr, M. Schubert, U. Hampel
Registration No. 25285 - Permalink

Untersuchung heterogener Strömungsmuster in Anstaupackungen mittels ultraschneller Röntgentomographie: Methode und Validierung
Sohr, J.; Litzka, A.; Schubert, M.; Flechsig, S.; Kenig, E. Y.; Hampel, U.
Abstract: Die Kombination von strukturierten Packungen unterschiedlicher geometrischer Oberflächen in Anstaupackungen (s. Abb. 1) führt zu einem axial verteilten Strömungsprofil bestehend aus Blasenströmung, Sprudelschicht und Filmströmung. Die Strömungsmorphologie variiert dabei in den einzelnen Strömungsbereichen sehr stark, sodass durch integrale Hold-up-Messungen kaum Rückschlüsse auf die individuellen Flüssigkeitsinhalte und Phasengrenzflächen gezogen werden können. Zeitlich und örtlich hochaufgelöste bildgebende Messverfahren, wie die ultraschnelle Röntgentomographie, können hier neue Erkenntnisse zur Fluiddynamik liefern [1].
Im Rahmen eines durch die DFG geförderten Projekts sind umfangreiche Fluiddynamikstudien mittels ultraschneller Röntgentomographie geplant. In einem ersten Schritt wird die ultraschnelle Röntgentomographie für die Untersuchung der unterschiedlichen Strömungsmorphologien validiert. Dazu werden mittels Micro-Computertomographie exakt charakterisierte statische Messphantome eingesetzt und Methoden zur Erfassung und Bewertung von Hold-up, Phasenverteilung und Phasengrenzflächen entwickelt. Die Validierung dieser Methoden ist Gegenstand dieses Beitrags.
[1] Janzen, A., Schubert, M., Barthel, F., Hampel, U., Kenig, E.Y., Chem. Eng. Process, (2013), 66, 20-26.
  • Lecture (Conference)
    Jahrestreffen der ProcessNet Fachgruppen Mechanische Flüssigkeitsabtrennung, Kristallisation, Phytoextrakte, Adsorption, Extraktion, Fluidverfahrenstechnik und Membrantechnik, 06.-10.03.2017, Köln, Deutschland
Registration No. 25283 - Permalink

A highly-parallel Monte-Carlo-Simulation of X-Ray-Scattering using a Particle-Mesh-Code on GPUs
Grund, A.
Abstract: Im Rahmen dieser Arbeit wurde eine Softwarelösung entwickelt, welche die Streuung von Röntgenstrahlung in Materie mit einem Monte-Carlo-Ansatz simuliert. Dazu wurde die Anwendung der Röntgen-Kleinwinkelstreuung (SAXS) zur Untersuchung der komplexen Prozesse bei der Interaktion intensiver kurzer Laserpulse mit Festkörpern als Motivation verwendet und beschrieben, wie Fouriertransformationen zur Näherung dieser Streuung verwendet werden können. Darauf aufbauend wurde einerseits die schnelle Fouriertransformation (FFT) als effiziente Implementierung für Computer vorgestellt und andererseits wurde auf die Limitierung dieses Ansatzes zur Beschreibung der Streuprozesse eingegangen. Um diese Limitierungen zu umgehen, wurde ein Modell entwickelt, das die Röntgenstrahlung mittels photonenähnlicher Teilchen beschreibt. Da für eine gute Abbildung der physikalischen Prozesse Milliarden solcher Teilchen benötigt werden, wurde die auf diesem Modell basierende Simulation von Anfang an auf die hoch parallele Struktur moderner Grafikprozessoren ausgelegt, welche es ermöglicht, sehr viele Teilchen gleichzeitig zu simulieren. Der implementierte Algorithmus wurde detailliert beschrieben, wobei gezielt auf die Besonderheiten von Grafikprozessoren eingegangen wurde. Da die richtige Wahl der Datentypen wesentlich für die Geschwindigkeit und Präzision des Algorithmus ist, wurde in einer umfassenden theoretischen Analyse und Tests der numerischen Genauigkeit der Implementation gezeigt, dass sogar mit Berechnungen in geringer Genauigkeit Ergebnisse erzielt werden, die keine wesentlichen Abweichungen von denen der exakten Berechnung aufzeigen. Dadurch können für typische Anwendungen kleinere Datentypen gewählt werden, was die Durchführung umfangreicherer Simulationen auf einer gegebenen Hardware erlaubt. Abschließend konnte die Korrektheit für ausgewählte Beispiele sowie eine gute Skalierbarkeit nachgewiesen werden.

English abstract:
In this thesis a software solution was developed that simulates the scattering of X-rays in matter using a Monte Carlo approach. The application of small-angle X-ray scattering in the studies of the complex processes occurring during the interaction of short intense laser pulses in solid matter provides the motivation for this work. Therefore this technique is described and it is shown how Fourier transformation can be used for approximating the scattering results. It is shown how they can be efficiently implemented in computers using the fast Fourier transform (FFT) and why this approach has limitations when describing scattering processes. To circumvent these, a model was developed that uses photon-like particles to describe the X-rays. Billions of such particles are required to provide a good approximation of the physical processes involved, which is why the simulation algorithm described in this work was designed from the ground up to support the massively parallel structure of modern graphic processing units (GPUs) allowing to simulate many particles at once. The implemented algorithm is described focusing on the special methods required to make the most use out of GPUs. As the choice of the appropriate data types is vital for the correctness and precision of the algorithm a comprehensive analysis and test of the numerical accuracy was deployed. It is shown that even reduced precision provides results that are accurate enough for a wide range of applications. Therefore, smaller data types can be used allowing to simulate much larger experiments on a given hardware. Finally the correctness and good scalability of the parallel algorithm are demonstrated.
Keywords: HPC, Exascale, Monte-Carlo, Photons, Scattering, SAXS
  • Diploma thesis
    TU Dresden, 2016
    Mentor: Prof. Dr. W. Nagel, Dr. T. Kluge, Dr. M. Bussmann, Dr. A. Knüpfer
Registration No. 25282 - Permalink

The photoluminescence response to structural changes of Yb implanted ZnO crystals subjected to non-equilibrium processing
Ratajczak, R.; Prucnal, S.; Guziewicz, E.; Mieszczynski, C.; Snigurenko, D.; Stachowicz, M.; Skorupa, W.; Turos, A.
Abstract: In this paper, we present the detailed study of optical and structural properties of Yb implanted single ZnO crystals. Hydrothermally grown wurtzite (0001) ZnO crystals were implanted with 150 keV Yb ions to fluencies of 5e14 and 1e15 at/cm2. After ion implantation, two different types of annealing were performed: rapid thermal annealing (RTA) and millisecond range flash lamp annealing (FLA). Crystalline quality, damage recovery, and Yb lattice site location were evaluated by the Channeling Rutherford Backscattering Spectrometry (RBS/c). It is shown that independent of the used annealing technique, defects formed in ZnO during ion implantation can be removed. Upon RTA performed at the temperature higher than 800C, strong out-diffusion of implanted Yb atoms and precipitation on the surface takes place. Consequently, the degradation of the photoluminescence (PL) efficiency is observed. The diffusion of implanted Yb during millisecond range FLA does not occur for such experimental conditions. Moreover, FLA treatment for 20 ms leads to the formation of single crystalline ZnO layer with Yb incorporated in the substitutional lattice sites. According to RBS/c and PL data, Yb atoms substituted in the Zn sublattice are predominantly in the 2þ oxidation state. The most intensive PL has been observed after annealing at 800C for 20 min which is accompanied with the reduction of Yb substitutional fraction and formation of octahedron Yb-oxygen clusters within ZnO.
Keywords: ZnO, ion implantation, FLA, Yb, photoluminescence, RBS Registration No. 25279 - Permalink

Architecture and mineral potential of the Paleoproterozoic Karrat Group, West Greenland: Results of the 2016 Season
Rosa, D.; Dewolfe, M.; Guarnieri, P.; Kolb, J.; Laflamme, C.; Partin, C. A.; Salehi, S.; Sørensen, E. V.; Thaarup, S.; Thrane, K.; Zimmermann, R.
Abstract: This report presents the preliminary results of the second field season of a joint project be- tween the Geological Survey of Denmark and Greenland (GEUS) and the Ministry of Min- eral Resources of Greenland (MMR) focusing on the Paleoproterozoic Karrat Group. The motivation for the expedition stems from an evaluation of the mineral potential along with understanding the stratigraphic architecture of the Karrat Group and aims to address stra- tigraphy, structure, and economic geology. Field work extended to northern Karrat Group outcrops, between Upernavik and Kullosuaq, and allowed further studies of the southern Karrat Group outcrops between Svartenhuk and Maarmorilik. The relationship between the Karrat Group and the Prøven Igneous Complex (PIC), emplaced between these two areas, was also assessed. The 2016 field season was aided by oblique aerial photography (“pho- toflying”), and hyperspectral techniques. Hyperspectral scenes were collected along cliff faces in the areas with the most prospective mineral potential, including Kangerluarsuk Fjord and Maarmorilik. These studies have built on the observations made in 2015, and have led either to the consolidation or to the revision of interpretations suggested after that season.
The exposed Karrat Group extends from ~71° to ~75°N and is composed of five formations: the Qeqertarssuaq (Lower Karrat Group), Qaarsukassak, Mârmorilik, Kangilleq, and Nûkavsak formations (Upper Karrat Group), of which the Qaarsukassak amd Kangilleq formations are informal. The lower and upper Karrat Group are separated by a regional erosional unconformity, which represents a revision to the Karrat stratigraphy established during the 2015 field season. The Karrat Group has not been differentiated north of Uper- navik due to the high metamorphic grade and polyphase deformation. Major goals of the field work included delineating contact relationships between units, documenting sedimen- tary structures that can define depositional environment(s), mapping the lateral extent and nature of extrusive mafic volcanism and volcaniclastic rocks in the upper Karrat Group (Kangilleq Formation), and determining the relative age relationships between units, which is elusive since several units are not in contact with one another. Integrated stratigraphy, sedimentology, volcanology, and ongoing geochronology will lead to a better understanding of the basin tectonic setting(s) in which the Karrat Group was deposited.
The deformation history of the area put forward after the 2015 season has been reviewed, and this succession is suggested: a NW-vergent D1 north of the Prøven Igneous Complex and channel flow in an orogen-scale NW-SE compression; D2 is characterised by E-W extension near Archean orthogneiss at Kangiusap Kuua and distal compression further to the E (previously assigned to D4); D3 is represented by structuring of the Kigarsima nappe overprinting all the other structures on Karrat Island and the peninsula to the SE (formerly described as D2); and, finally, a NW-SE compression, documented in the Maarmorilik area, is now relabeled as D4 (previously assigned to D3).
The time-stratigraphic horizon above and laterally to the Kangilleq Formation volcanism represents a period of VMS-formation on (or just below) the seafloor. Sampling of massive sulfides has yielded anomalous base metal concentrations (typically <0.3% Cu+Pb+Zn). However, because it is known that massive sulfide horizons can display zonations from low-grade to gold- and/or base metal-rich zones, these horizons potentially constitute tar- gets for future base metal and/or gold exploration in the Karrat region.
A Mississippi-Valley Type (MVT) origin is suggested for the Zn-Pb mineralisation in the Qaarsukassak Formation (RTZ Discovery), which might therefore have formed at the same time as the mineralisation in the Mârmorilik Formation. This is based on proximity of the Qaarsukassak Formation mineralisation to Archean rocks and the association of its distri- bution with marble and chert horizons. The possible role of evaporites and their diapirism in the mineralising process has been highlighted in the Mârmorilik Formation, by establishing the proximity of the known Lower Mârmorilik Formation showings to what can be interpret- ed to have been an evaporite horizon (now a “mottled pelite”). From this horizon, evaporites possibly ascended and were emplaced, as diapirs, within the Upper Mârmorilik Formation, underneath the pelites that would have acted as cap rock (where the Black Angel deposit is). Diapirism was likely triggered by deformation, during which evaporites flowed along thrust planes, as has been tentatively documented through the hyperspectral survey.
Possible silicate-silicate liquid immiscibility accompanied by silicate-sulfide immisciblity, occurred in a gabbro complex identified on the eastern side of Nutaarmiut island, to the southeast of Upernavik. The degree of PGE-Au enrichment in the sulfide has not been tested yet, but could potentially be of economic significance.
  • Other report
    København: GEUS Geological Survey of Denmark and Greenland, 2017
    112 Seiten
Registration No. 25270 - Permalink

Validation and update of the baseline model for poly-disperse bubbly flows
Lucas, D.; Krepper, E.; Rzehak, R.; Ziegenhein, T.; Ma, T.; Liao, Y.
Abstract: For the consolidation of CFD-methods basing on the multi-fluid approach a baseline model strategy has been developed. Following this strategy a baseline model for poly-disperse bubbly flows was recently defined. This model is presented and an overview on the status as well as selected examples for the validation are given. Furthermore new developments regarding bubble induced turbulence, lateral lift force and bubble coalescence and breakup modelling are presented.
Keywords: baseline model, bubbly flow, CFD, bubble induced turbulence, lateral lift force, coalescence, breakup
  • Lecture (Conference)
    28th Meeting of the German CFD Network of Competence, 07.03.2017, Garching, Deutschland
Registration No. 25262 - Permalink

Annual Report 2016 - Institute of Ion Beam Physics and Materials Research
Faßbender, J.; Heera, V.; Helm, M.; Zahn, P. (Editors)
Abstract: Content:
Preface
Selected publications
Statistics
(Publications and patents, Concluded scientific degrees; Appointments and honors; Invited conference contributions, colloquia, lectures and talks; Conferences, workshops, colloquia and seminars; Exchange of researchers; Projects)
Doctoral training programme
Experimental equipment
User facilities and services
Organization chart and personnel
  • Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-078 2017

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Registration No. 25256 - Permalink

Self-Organized Semiconductor Surface Patterning of Pure and Compound Semiconductors by Polyatomic Ion Irradiation
Bischoff, L.; Böttger, R.; Pilz, W.; Facsko, S.; Heinig, K.-H.
Abstract: Irradiation of solids by heavy polyatomic ions (e.g. Aunm+ or Binm+) can cause localized melting at the ion impact point due to the enhanced energy density in the collision cascade of a polyatomic heavy ion impact [1,2]. Former studies demonstrated the formation of high aspect ratio, hexagonal dot patterns on Ge, Si or GaAs after high fluence, normal incidence irradiation using a mass separated FIB system choosing a suited combination of energy density deposition (i.e. poly- or monatomic ions) and substrate temperature, which facilitated transient melting of the ion collision cascade volume [2-5].
This study underscores the universality of this ion impact-melting-induced, self-organized pattern formation mechanism probing the compound semiconductor GaSb under polyatomic Aunm+ ion irradiation with various irradiation conditions in particular, ion species, fluence, energy/atom, temperature and angle of incidence.
Calculations of the needed melting energies per atom (Emelt) for different materials show, that among others GaSb is a preferring candidate for a successful surface patterning by mon- and polyatomic heavy ions whereas i.e. the surface of SiC remains stable under the given conditions.
HRSEM, AFM and EDX analysis of irradiated surfaces reveal that for compound semiconductors, additional superstructures are evolving on top of the regular semiconductor dot patterns, indicating superposition of a second dominant driving force for pattern self-organization.

[1] C. Anders et al., Phys. Rev. B 87 (2013) 245434.
[2] L. Bischoff et al., Nucl. Instr. Meth. Phys. Res. B 272 (2012) 198.
[3] R. Böttger et al., J. Vac. Sci Technol. B 30 (2012) 06FF12.
[4] R. Böttger et al., Phys. Stat. Sol. RRL 7 (2013) 501.
[5] L. Bischoff et al., Appl. Surf. Sci. 310 (2014) 154.
Keywords: Self-Organized Surface Patterning; Polyatomic Ion Irradiation; Focused ion Beam
  • Lecture (Conference)
    Raith-FIB- Workshop, 28.-30.03.2017, Dortmund, Germany
Registration No. 25250 - Permalink

Scalable, multi-GPU photon tracing for in-situ X-ray radiation transport in solid density plasmas
Garten, M.ORC; Grund, A.; Huebl, A.; Burau, H.; Widera, R.; Kluge, T.; Fortmann-Grote, C.; Bussmann, M.
Abstract: We present our scientific roadmap towards in-situ modeling of non-LTE interactions of XFEL type X-rays with solid density plasmas using a symbiosis of our performance portable, open source, 3D3V particle-in-cell (PIC) code PIConGPU and its X-ray tracing prototype ParaTAXIS. Treating radiation transport via various atomic processes will enable us to synthesize detector signals and gain predictive capabilities for upcoming pump-probe experiments at the European XFEL. With the world’s fastest particle-in-cell code PIConGPU and the raw computational power of the largest high performance computers we open up the possibility for large-scale case studies of unprecedented repeatability.
Keywords: ParaTAXIS, PIConGPU, radiation transport, plasma physics, atomic processes
  • Poster
    2017 Joint ICTP-IAEA School on Atomic Processes in Plasmas, 27.02.-03.03.2017, Trieste, Italia
Registration No. 25245 - Permalink

Interactions between U(VI) doped CSH phases and high saline brines
Wolter, J.-M.; Schmeide, K.; Stumpf, T.
Abstract: Cementitious materials will be used for the geotechnical barrier of a deep geological repository where long-lived radioactive waste like used fuel rods will be stored [1]. Calcium silicate hydrate (CSH) phases, as main component of hardened cement paste, are known for their retention potential for radionuclides like U which is the main component of used fuel rods [2].

The formation water of North German clay stone formations is characterized by high ionic strengths [3], which potentially lead to a corrosion of concrete. Thus, with respect to long-term safety assessment of cement containing repositories chemical alteration processes at high saline conditions have to be studied. Therefore, the leaching of U(VI) doped CSH phases in high ionic strengths electrolyte solutions is studied in batch experiments in combination with spectroscopic methods.

The approach of this study is to get a molecular understanding of interactions between U(VI) doped CSH phases and high ionic strengths electrolyte solutions. For this, batch leaching experiments were performed in combination with spectroscopic methods.

The formation of CSH phases is confirmed by XRD and IR / Raman spectroscopy. The TRLFS spectra obtained for U(VI) doped CSH phases are comparable to those reported by Tits et al. [4]. Thus, an incorporation of U(VI) in the CSH phases is verified. The results of leaching experiments are exemplarily shown for Ca for the CSH phase with C/S ratio of 1.6 for in Figure. 1. In presence of NaCl and Na2SO4, Ca is released into the supernatant solution. This mainly can be attributed to a release of Ca from the interlayers of CSH phases. Simultaneously, the pH values of the supernatant solutions increase to values between 11.2 and 12, depending on the C/S ratio. In the presence of NaHCO3, the Ca concentration in solution is much lower due to precipitation of CaCO3. In this case, pH values between 11.4 and 10.1 are observed.

In the presence of NaCl and Na2SO4, the release of Si and U is minimal. In the presence of NaHCO3, however, the Si and U concentration in solution is increased. Since Si can only be released from the complex layers of CSH phases, the release of Si and simultaneously, the release of U can be related to a decomposition of the CSH phases in the presence of carbonate. Spectroscopic investigations also confirmed the decomposition of CSH phases and the release of U due to carbonate.
Keywords: CSH phases, uranium, North Germany, clay stone, cement, retention, leaching, PXRD, TRLFS, IR, RAMAN, saline, salt
  • Contribution to proceedings
    ABC Salt V, 26.-28.03.2017, Ruidoso, New Mexico, USA
    Proceedings of ABC Salt V
Registration No. 25238 - Permalink

Annual Report 2016 Institute of Resource Ecology
Stumpf, T.; Foerstendorf, H.ORC; Bok, F.; Richter, A.
Abstract: The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden – Rossendorf (HZDR). The research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”...
  • Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-079 2017
    ISSN: 2191-8708

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Registration No. 25236 - Permalink

Verbundprojekt WASA-BOSS: Weiterentwicklung und Anwendung von Severe Accident Codes – Bewertung und Optimierung von Störfallmaßnahmen; Teilprojekt B: Druckwasserreaktor-Störfallanalysen unter Verwendung des Severe-Accident Code ATHLET-CD – Abschlussbericht
Jobst, M.; Kliem, S.; Kozmenkov, Y.; Wilhelm, P.
Abstract: Innerhalb des Vorhabens wurde ein ATHLET-CD-Eingabedatensatz für einen generischen deutschen DWR vom Typ KONVOI entwickelt. Das ATHLET-CD-Modell wurde für die Simulation schwerer Störfälle aus den Störfallkategorien Station Blackout (SBO) und Kühlmittelverluststörfällen mit kleinen Lecks (SBLOCA) eingesetzt. Dabei ist die vollständige Störfalltransiente für den Zeitbereich zwischen dem einleitenden Ereignis bis zum Versagen des Reaktordruckbehälters (RDB) abgedeckt und alle wesentli-chen Phänomene schwerer Störfällen werden abgebildet: Beginn der Kernaufheizung, Spaltproduktfrei-setzung, Aufschmelzen von Brennstoff- und Absorbermaterialien, Oxidationsprozesse mit Freisetzung von Wasserstoff, Verlagerung von geschmolzenem Material, Verlagerung in das untere Plenum, Schä-digung und Versagen des RDB. Das Modell wurde für die Analyse möglicher präventiver und mitigativer Notfallmaßnahmen für SBO und SBLOCA angewandt. Dafür wurden die Notfallmaßnahmen primärseitige Druckentlastung (PDE), primärseitiges Einspeisen mit mobilen Pumpensystemen sowie für SBLOCA das verzögerte Einspeisen der kaltseitigen Druckspeicher untersucht und die Eigenschaften und Einleitekriterien der Maßnahmen variiert. Es wurden die Zeitverläufe der Unfallszenarien analysiert und die verbleibenden Zeitspannen für die Einleitung zusätzlicher Maßnahmen ermittelt. Für ein SBO-Szenario mit PDE wurde für die Frühphase der Transiente (bis zum Beginn der Kernschmelze) eine Unsicherheits- und Sensititvitätsanalyse durchgeführt. Zusätzlich wurde für ein SBLOCA-Szenario ein Code-zu-Code-Vergleich zwischen ATHLET-CD und dem Störfallcode MELCOR erarbeitet.
Keywords: Druckwasserreaktor, Schwere Störfälle, Notfallmaßnahmen, ATHLET-CD-Simulation / Pressurized Water Reactor, Severe accidents, Accident management measures, ATHLET-CD simulations
  • Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-080 2017

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Registration No. 25233 - Permalink

ROBL-II: A dedicated actinide beamline for X-ray spectroscopy and scattering techniques
Scheinost, A. C.; Kvashnina, K.; Hennig, C.; Exner, J.; Rossberg, A.; Schmidt, M.; Stumpf, T.
Abstract: The Rossendorf Beamline (ROBL) operates since 1999 as a single-branch, double-experiment, multi-purpose X-ray beamline for radiochemistry and materials sciences. After 13 years of successful operation, the optical components of ROBL were replaced by state-of-the-art equipment, including a LN2-cooled double-crystal/double-multilayer monochromator, and a 1.2-m double-toroid focusing mirror with Pt and Rh coatings and 1.0 µrad slope errors. Since 2015, both experimental stations belong to the Institute of Resource Ecology at HZDR and are dedicated to study actinides. In 2016, a major upgrade program started to provide additional or largely improved techniques:
(1) A five-crystal Johann-type spectrometer with variable Rowland circle of 0.5 to 1 m to measure high-energy-resolution fluorescence detection XANES, XES and RIXS [1].
(2) A new 6-circle diffractometer for powder diffraction, crystal truncation rod (CTR) and resonant anomalous X-ray reflectivity (RAXR) measurements.
(3) A large 2D detector will further support the structure analysis of materials (PXRD, single crystal diffraction, PDF analysis).
(4) A new Ge-based energy dispersive detection system with ultrafast electronics to obtain detection limits for bulk XAS near or even below 1 ppm, and automated sample feeders for room temperature and cryogenic (10 K) conditions to enable a high sample throughput.
All experiments will be available from 2020 on in a control area comprising two hutches connected by a common lock room, which allows an easy exchange of radioactive samples (alpha emitters with total activity below 185 MBq) between four experimental stations.
Furthermore, ROBL-II will significantly benefit from the new electron storage ring of the ESRF installed in 2019/2020. ROBL-II’s new source, a short bending magnet, will provide a photon flux of 1013 ph/s across a wide energy range (3 to 35 keV). The much lower vertical divergence will allow us to obtain a spot size of 30 x 70 µm2 with the toroid mirror, thereby raising the photon density by an order of magnitude as compared to the current storage ring.
The complete experimental portfolio of ROBL-II will be available to users from 2020 on, for more than 200 (24-h) days per year, establishing the key role of ROBL-II for synchrotron-based actinide chemistry, and additionally providing beamtime for fundamental chemistry, catalysis, materials and earth sciences.

[1] K. O. Kvashnina and A. C. Scheinost, Journal of Synchrotron Radiation 2016, 23, 836-841.
Keywords: synchrotron actinides XAFS XES XRD CTR RAXR
  • Invited lecture (Conferences)
    AnXAS 2017: 8th Workshop on Speciation, Techniques, and Facilities for Radioactive Materials at Synchrotron Light Sources, 10.-13.04.2017, Oxford, United Kingdom
Registration No. 25227 - Permalink

A novel nanobody-based target module for retargeting of T lymphocytes to EGFR-expressing cancer cells via the modular UniCAR platform
Albert, S.; Arndt, C.; Feldmann, A.; Bergmann, R.; Bachmann, D.; Koristka, S.; Ludwig, F.; Ziller-Walter, P.; Kegler, A.; Gärtner, S.; Schmitz, M.; Ehninger, A.; Cartellieri, M.; Ehninger, G.; Pietzsch, H.-J.; Pietzsch, J.; Steinbach, J.; Bachmann, M.
Abstract: Recent treatments of leukemias with chimeric antigen receptor (CAR)-expressing T cells underline their impressive therapeutic potential. However, once adoptively transferred into patients, there is little scope left to shut them down after elimination of tumor cells or in case adverse side effects occur. This becomes of special relevance if they are directed against commonly expressed tumor associated antigens (TAAs) such as receptors of the ErbB family. To overcome this limitation, we recently established a modular CAR platform technology termed UniCAR. UniCARs are not directed against TAAs but instead against a unique peptide epitope on engineered recombinant targeting modules (TMs) which guide them to the target. In the absence of a TM UniCAR T cells are inactive. Thus an interruption of any UniCAR activity requires an elimination of unbound TM and the TM complexed with UniCAR T cells. Elimination of the latter one requires a disassembly of the UniCAR-TM complexes. Here we describe a first nanobody (nb)-based TM directed against EGFR. The novel TM efficiently retargets UniCAR T cells to EGFR positive tumors and mediates highly efficient target-specific and target-dependent tumor cell lysis both in vitro and in vivo. After radiolabeling of the novel TM with 64Cu and 68Ga we analyzed its biodistribution and clearance as well as the stability of the UniCAR-TM complexes. As expected unbound TM is rapidly eliminated while the elimination of the TM complexed with UniCAR T cells is delayed. Nonetheless, we show that UniCAR-TM complexes dissociates in vitro and in vivo in a concentration-dependent manner in line with the concept of a repeated stop and go retargeting of tumor cells via the UniCAR technology.
Keywords: CAR, EGFR, Retargeting, T cell, T cell therapy Registration No. 25222 - Permalink

Li, Co, Nd ... - Strategische Metalle für die Elektromobilität
Rudolph, M.ORC
Abstract: Elektromobilität ist zurzeit in aller Munde; von eAutos, eBikes und Pedelecs hat jeder schon gehört. Die 32. Hochschultage Physik widmen sich dem gegenwärtigen Stand der Technik und der Zukunft dieses spannenden Forschungsgebietes. Vortragende aus Wissenschaft und Industrie greifen ein breites Spektrum an Aspekten auf, das sicherlich Anregungen für lebhafte Diskussionen bietet.
Die Veranstaltung richtet sich nicht nur an Lehrerinnen und Lehrer, sondern auch an die breite Öffentlichkeit, an Studierende und natürlich auch an die Mitglieder des Fachbereichs Physik.
  • Invited lecture (Conferences)
    32. Hochschultage Physik, 13.-14.02.2017, Marburg, Deutschland
Registration No. 25216 - Permalink

Als Ingenieur in der Forschung - an der Grenzfläche von Wissenschaft, Gesellschaft und Anwendung
Rudolph, M.ORC
Abstract: Ingenieure sind vielseitige Problemlöser und daher sehr gefragt in der Forschung, sowohl in Industrie wie auch in der Wissenschaft. Noch bis ins 19. Jahrhundert aber waren Ingenieure nicht wirklich geduldet als Wissenschaftler, nicht ohne Grund ist der Doktorgrad der Ingenieurwissenschaften in Deutschland seit dem als einziger nicht lateinisch und versehen mit einem Bindestrich, also Dr.-Ing. und nicht Dr. rer. tech. Der moderne Ingenieur ist aber schon längst ein angewandter Naturwissenschaftler und nicht nur geschickter Tüftler. Der Beitrag soll anhand der eigenen Erfahrungen des Vortragenden einen Einblick geben über die spannenden Themen eines Ingenieurs in der Forschung. Ganz speziell werden darüber hinaus die Felder der Grenzflächenverfahrenstechnik und der Ressourcentechnologie vorgestellt und aufgegriffen. Dabei soll auch das Spannungsfeld aus Wissenschaft, Gesellschaft und Anwendung beleuchtet werden.
  • Invited lecture (Conferences)
    VDI suj Freiberg - Stammtisch, 09.01.2017, Freiberg, Deutschland
Registration No. 25215 - Permalink

Uranium mining, resulting ecological problems and references to spectroscopic methods
Baumann, N.
Abstract: Ecological problems resulting from the reckless uranium mining in Saxony and Thuringia within approximately 45 years are illustrated, and contributions in determination of these problems by the spectroscopic methods TRFLS and EXAFS are showed.
Keywords: uranium, speciation, migration and sorption behavior, TRLFS, EXAFS
  • Invited lecture (Conferences)
    Invited presentation, 03.03.2017, Sriracha, Thailand
Registration No. 25209 - Permalink

Analysis for Optimum Conditions for Recovery of Valuable Metals from E-waste Through Black Copper Smelting
Reuter, M. A.; Rhamdhani, M. A.; Brooks, G. A.; Masood, S.; Shuva, M. A. H.; Firdaus, M.
Abstract: Declining grade of primary ores and resource efficiency have led us to process more alternative metal resources such as e-waste. One of the processing routes for extracting valuable metals from e-waste is through the black copper smelting. However, the underlying knowledge of the thermodynamics behaviour of the valuable metals contained in e-waste during smelting are limited which prevent us from developing an optimised process to recover all the metals. These different metals clearly will have different favourable conditions for their extraction. To illustrate this, the distribution behaviour of germanium (Ge) and palladium (Pd) between liquid copper and ferrous-calcium-silicate slag during black copper smelting was analysed. It was demonstrated that oxygen partial pressure and slag composition affect the partitioning of these metals to the copper phase and the favourable slag chemistry for recovering these metals is opposing. Considering the available thermodynamic data of these metals, an analysis for the optimum conditions is presented.
Keywords: Resources efficiency E-waste Black copper Metal recovery
  • Book chapter
    Hwang, Jiang, Kennedy, Yücel, Pistorius; Seshadri, Zhao, Gregurek; Keskinkilic: Analysis for Optimum Conditions for Recovery of Valuable Metals from E-waste Through Black Copper Smelting, New York: Springer International Publishing, 2017, 978-3-319-51339-3, 419-427
    DOI-Link: http://dx.doi.org/10.1007/978-3-319-51340-9_41
Registration No. 25205 - Permalink

Individualized early death and long-term survival prediction after stereotactic radiosurgery for brain metastases of non-small cell lung cancer: Two externally validated nomograms
Zindler, J.; Jochems, A.; Lagerwaard, F.; Beumer, R.; Troost, E.; Eekers, D.; Compter, I.; van der Toorn, P.-P.; Essers, M.; Oei, B.
Abstract: Introduction: Commonly used clinical models for survival prediction after stereotactic radiosurgery (SRS) for brain metastases (BMs) are limited by the lack of individual risk scores and disproportionate prognostic groups. In this study, two nomograms were developed to overcome these limitations.
Methods: 495 patients with BMs of NSCLC treated with SRS for a limited number of BMs in four Dutch radiation oncology centers were identified and divided in a training cohort (n = 214, patients treated in one hospital) and an external validation cohort n = 281, patients treated in three other hospitals). Using the training cohort, nomograms were developed for prediction of early death (<3 months) and long-term survival (>12 months) with prognostic factors for survival. Accuracy of prediction was defined as the area under the curve (AUC) by receiver operating characteristics analysis for prediction of early death and long term survival. The accuracy of the nomograms was also tested in the external validation cohort.
Results: Prognostic factors for survival were: WHO performance status, presence of extracranial metastases, age, GTV largest BM, and gender. Number of brain metastases and primary tumor control were not prognostic factors for survival. In the external validation cohort, the nomogram predicted early death statistically significantly better (p < 0.05) than the unfavorable groups of the RPA, DS-GPA, GGS, SIR, and Rades 2015 (AUC = 0.70 versus range AUCs = 0.51–0.60 respectively). With an AUC of 0.67, the other nomogram predicted 1 year survival statistically significantly better (p < 0.05) than the favorable groups of four models (range AUCs = 0.57–0.61), except for the SIR (AUC = 0.64, p = 0.34). The models are available on www.predictcancer.org.
Conclusion: The nomograms predicted early death and long-term survival more accurately than commonly used prognostic scores after SRS for a limited number of BMs of NSCLC. Moreover these nomograms enable individualized probability assessment and are easy into use in routine clinical practice.
Keywords: Individualized brain metastases Stereotactic radiosurgery Prognostic models Registration No. 25204 - Permalink

PIConGPU the 3D3V Particle-in-Cell Code Developed at HZDR – A Status Update
Huebl, A.ORC; Garten, M.; Pausch, R.; Matthes, A.; Branco, J.; Steiniger, K.; Burau, H.; Grund, A.; Debus, A.; Kluge, T.; Widera, R.; Bussmann, M.
Abstract: PIConGPU is currently the fastest particle-in-cell code in the world. New physics models are continuously developed and, after thorough testing, included in our open-source software.

In this talk we will give an overview on the recent upgrades in PIConGPU, covering new ionization schemes including ADK, Keldysh and collisional ionization, a QED and bremsstrahlung module that brings photons to the code, and various new laser implementations to better model lasers used in experiments and to enable the simulation of novel light source concepts like TWTS. We will present various synthetic diagnostic methods such as the spectrally resolved radiation detectors, the in-situ phase space diagnostic and our ParaTAXIS framework, which is able to simulate small angle photon scattering of an external x-ray pulse probing laser-driven solid-density targets. Furthermore, we will briefly discuss numerous code improvements which boost performance, unify data exchange and analysis via the openPMD standard for open, reproducible science, and our steerable live visualization. Finally we will showcase several simulations ranging from laser wakefield acceleration via ionization injection, to ion acceleration via laser interaction with spherical, perfectly isolated, mass-limited targets (both experimentally realized) to radiation signatures of a shear surface instability.
Keywords: Simulation, LPA, PIC, PIConGPU, FLOSS, Open Source, Modeling, Synthetic Diagnostics
  • Lecture (Conference)
    Third MT student retreat, Third Annual Matter & Technologies Meeting, 30.-31.01.2017, Darmstadt, Germany
Registration No. 25203 - Permalink

Proton implantation for electrical insulation of the InGaAs/InAlAs superlattice material used in 8–15 μm-emitting quantum cascade lasers
Kirch, J. D.; Kim, H.; Boyle, C.; Chang, C.-C.; Mawst, L. J.; Lindberg Iii, D.; Earles, T.; Botez, D.; Helm, M.; von Borany, J.; Akhmadaliev, S.; Böttger, R.; Reyner, C.
Abstract: We demonstrate the conversion of lattice-matched InGaAs/InAlAs quantum-cascade-laser (QCL) active-region material into an effective current-blocking layer via proton implantation. A 35-period active region of an 8.4 μm-emitting QCL structure was implanted with a dose of 5 × 10^14 cm−2 protons at 450 keV to produce a vacancy concentration of ∼10^19 cm−3. At room temperature, the sheet resistance, extracted from the Hall measurements, increases by a factor of ∼240 with respect to that of an unimplanted material. Over the 160–320 K temperature range, the activation energy of the implanted-material Hall sheet-carrier density is 270 meV. The significant increase in room-temperature sheet resistance indicates that upon implantation deep carrier traps have been formed in the InAlAs layers of the superlattice. Fabricated mesas show effective current blocking, at voltages ≥10 V, up to at least 350 K. Thus, the implanted InGaAs/InAlAs superlattices are highly resistive to at least 350 K heat sink temperature. Such implanted material should prove useful for effective current confinement in 8–15 μm-emitting InP-based single-emitter QCL structures as well as in resonant leaky-wave coupled phase-locked arrays of QCLs.
Keywords: Quantum cascade lasers, Ion Implantation, Protons, Superlattices, Leakage currents, Carrier mobility Registration No. 25201 - Permalink

Our strategic approach: Reactive transport modelling based on parameters obtained from batch and GeoPET column experiments: example from leaching of a fractured drill core
Karimzadeh, L.; Kulenkampff, J.; Schymura, S.; Eichelbaum, S.; Lippmann-Pipke, J.
Abstract: Abstract

The EU-funded research project BIOMOre[1] is designed to develop a new technological concept for the in-situ recovering of copper from deep European Kupferschiefer ore deposits by using controlled stimulation of pre-existing fractures in combination with in-situ bioleaching. The BIOMOre project mainly focuses on the leaching experiments in lab and field scale and the related reactive transport modeling including the required backcoupling from geochemical reactions on the hydrodynamics as well as the upscaling. We here present most recent, preliminary results that focus on reactive transport simulations on a drill core sample in 4D (3D+t). While we still use synthetic porosity and velocity fields, the model is capable of later imported velocity and effective porosity fields obtained from the transport process visualization method, GeoPET. This technique has been established by members of the Reactive Transport Division of the HZDR in the past decade and allows the direct, non-destructive, quantitative spatiotemporal visualization of (reactive) transport processes in natural geological media on drill-core scale [2-6].
A mechanically induced fracture was designed with a geomechanical shear test in a calciferous sandstone drill core sample obtained from the Kupferschiefer ore formation. While the long term leach experiment is still ongoing the pH value and preliminary Ca+ and Cl- contents from the breakthrough are aligned with those from the reactive transport modelling conducted by means of iCP[7] (an interface coupling of the finite element based code COMSOL Multiphysics® with the geochemical code PhreeqC). The model consideres mineral leaching due to the injection of an acidic solution with pH of 1.5 to the fracture. Currently the flow is still simulated by the Forchheimer equation [8] in matrix and fracture. The chemical processes considered in the model are kinetically controlled mineral dissolution and precipitation in the porous media simulated by means of PHREEQC[9] and advective-dispersive transport in the fracture and matrix diffusion in the rock mass calculated by COMSOL Multiphysics. Calcite dissolution and gypsum precipitation were monitored in the results of the model.
Our further tasks in the project will consider more realistic structure geometry of rock core sample (fracture and matrix) and quantified advective distributions obtained from GeoPET.
Keywords: Reactive transport modeling, GeoPET, In-situ leaching, iCP
  • Invited lecture (Conferences)
    7th Reactive Transport PhD Workshop, 23.02.2017, Leipzig, Germany
Registration No. 25200 - Permalink

Comparison of toxicity and outcome in advanced stage non-small cell lung cancer patients treated with intensity-modulated (chemo-)radiotherapy using IMRT or VMAT
Wijsman, R.; Dankers, F.; Troost, E. G. C.; Hoffmann, A. L.; van der Heijden, E. H. F. M.; de Geus-Oei, L. F.; Bussink, J.
Abstract: Retrospective evaluation of 188 advanced stage non-small cell lung cancer patients treated with IMRT or VMAT revealed a limited increase of moderate to severe acute esophageal toxicity after VMAT. Acute pulmonary toxicity and severe late toxicity were low. Overall survival did not differ between the IMRT and VMAT groups.
Keywords: Non-small cell lung cancer Intensity-modulated radiation therapy Volumetric-modulated radiation therapy Toxicity Registration No. 25196 - Permalink

Holographic QCD phase diagram with critical point from Einstein-Maxwell-dilaton dynamics
Knaute, J.; Yaresko, R.; Kämpfer, B.
Abstract: Supplementing the holographic Einstein-Maxwell-dilaton model of [O. DeWolfe, S.S. Gubser, C. Rosen, Phys. Rev. D83 (2011) 086005; O. DeWolfe, S.S. Gubser, C. Rosen, Phys. Rev. D84 (2011) 126014] by input of lattice QCD data for 2+1 flavors and physical quark masses for the equation of state and quark number susceptibility at zero baryo-chemical potential we explore the resulting phase diagram over the temperature-chemical potential plane. A first-order phase transition sets in at a temperature of about 112 MeV and a baryo-chemical potential of 989 MeV. We estimate the accuracy of the critical point position in the order of approximately 5% by considering different low-temperature asymptotics for the second-order quark number susceptibility. The critical pressure as a function of the temperature has a positive slope, i.e. the entropy per baryon jumps up when crossing the phase border line from larger values of temperature/baryo-chemical potential, thus classifying the phase transition as a gas-liquid one. The updated holographic model exhibits in- and outgoing isentropes in the vicinity of the first-order phase transition.

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Registration No. 25195 - Permalink

The Beautiful Molecule: 30 Years of C60 and its Derivatives
Acquah, S. F. A.; Penkova, A. V.; Markelov, D. A.; Semisalova, A. S.; Leonhardt, B. E.; Magi, J. M.
Abstract: In 1996 Sir Harold W. Kroto, Robert F. Curl and Richard E. Smalley were honored with the Nobel Prize in Chemistry for the discovery of fullerenes. The advent of these new forms of carbon heralded a race to understand the physical and chemical properties. C60 is virtually insoluble in polar solvents but is partially soluble in benzene, toluene, and carbon disulfide. This made the processing of fullerenes for new applications fairly problematic. However, the physical and chemical properties of these cage structures may be tailored for a wide range of applications. Some of the difficulties in processing have been overcome by using novel fullerene derivatives. The functionalization of the fullerene core with different chemical moieties provided a vector towards potential applications in drug delivery, optoelectronics, electrochemistry and organic photovoltaics. In this review, we will take a closer look at the features of some of the fullerene derivatives that have reinvigorated the field of fullerene research. Water-soluble polyhydroxylated fullerenes such as fullerenol have demonstrated the potential for good electron transfer and optical transmission, while hydrophobic fullerene derivatives have shown promising avenues for catalytic applications.
2015 marked the 30th anniversary of the discovery of fullerenes, with celebrations around the world including an event by the Royal Society of Chemistry, bringing together many of Sir Harold Kroto’s former students. The event also coincided with the recent discovery of C60+ in space after a complex twenty-year search. It is with sadness that we, Harry’s Research Group at Florida State University, and his international collaborators, reflect on the passing of Sir Harold Kroto. His dedication to science and commitment to science communication through the VEGA Science Trust and the Global Educational Outreach for Science Engineering and Technology (GEOSET) initiative help to raise awareness of the challenges for science in the modern world. We will continue to inspire young students through outreach activities he initiated.
Keywords: Fullerene, fullerenol, metallofullerenes, mechanical properties, electrical properties

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Registration No. 25193 - Permalink

Prediction of countercurrent flow limitation and its uncertainty in horizontal and slightly inclined pipes
Murase, M.; Utanohara, Y.; Kusunoki, T.; Yamamoto, Y.; Lucas, D.; Tomiyama, A.
Abstract: We proposed prediction methods for countercurrent flow limitation (CCFL) in horizontal and slightly inclined pipes with one-dimensional (1-D) computations and uncertainty of computed CCFL. In this study, we applied the proposed methods to a full-scale pressurizer surge line [inclination angle theta = 0.6 deg, diameter D = 300 mm, and ratio of the length to the diameter (L/D) = 63] in a specific pressurized water reactor, performed 1-D computations and three-dimensional (3-D) numerical simulations, and found that uncertainties caused by effects of the diameter and fluid properties on CCFL were small. We also applied the proposed methods to experiments for hot-leg and surge line models (theta = 0 and 0.6 deg, D = 0.03 to 0.65 m, and L/D = 4.5 to 63) to generalize them, performed 1-D computations, and found that uncertainties caused by effects of theta and L on CCFL were large due to the setting error for theta and differences among experiments. This shows that a small-scale air-water experiment with the same theta and L/D as those in an actual plant is effective to reduce the uncertainty of CCFL prediction.
Keywords: PWR hot leg, pressurizer surge line, countercurrent flow limitation Registration No. 25189 - Permalink

Δ(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES
Adamczewski-Musch, J.; Agakishiev, G.; Arnold, O.; Atomssa, E. T.; Behnke, C.; Berger-Chen, J. C.; Biernat, J.; Blanco, A.; Blume, C.; Böhmer, M.; Bordalo, P.; Chernenko, S.; Deveaux, C.; Dreyer, J.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Franco, C.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gill, K.; Golubeva, M.; Guber, F.; Gumberidze, M.; Harabasz, S.; Hennino, T.; Hlavac, S.; Höhne, C.; Holzmann, R.; Ierusalimov, A.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Kardan, B.; Koenig, I.; Koenig, W.; Kolb, B. W.; Korcyl, G.; Kornakov, G.; Kotte, R.; Krása, A.; Krebs, E.; Kuc, H.; Kugler, A.; Kunz, T.; Kurepin, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Lorenz, M.; Mahmoud, T.; Maier, L.; Maurus, S.; Mangiarotti, A.; Markert, J.; Metag, V.; Michel, J.; Morozov, S.; Müntz, C.; Münzer, R.; Naumann, L.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Petousis, V.; Pietraszko, J.; Przygoda, W.; Ramos, S.; Ramstein, B.; Rehnisch, L.; Reshetin, A.; Rost, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schmidt-Sommerfeld, K.; Schuldes, H.; Sellheim, P.; Siebenson, J.; Silva, L.; Sobolev, Y. G.; Spataro, S.; Ströbele, H.; Stroth, J.; Strzempek, P.; Sturm, C.; Svoboda, O.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Wendisch, C.; Wirth, J.; Zanevsky, Y.; Zumbruch, P.
Abstract: In this paper we report on the investigation of Δ(1232) production and decay in proton-proton collisions at a kinetic energy of 1.25 GeV measured with HADES. Exclusive dilepton decay channels ppe+e- and ppe+e-γ have been studied and compared with the partial wave analysis of the hadronic ppπ0 channel. They allow to access both Δ+ -> π0(e+e-γ)p and Δ+ -> pe+e- Dalitz decay channels. The perfect reconstruction of the well known π0 Dalitz decay serves as a proof of the consistency of the analysis. The Δ Dalitz decay is identified for the first time and the sensitivity to N-Δ transition form factors is tested. The Δ(1232) Dalitz decay branching ratio is also determined for the first time; our result is (4.19 +- 0.62 syst. +- 0.34 stat.) x 10-5, albeit with some model dependence. Registration No. 25187 - Permalink

Determination of N* excitation functions in associated strangeness production in p+p collisions
Münzer, R.; Fabbietti, L.; Epple, E.; Lu, S.; Klose, P.; Hauenstein, F.; Herrmann, N.; Grzonka, D.; Leifels, Y.; Maggiora, M.; Pleiner, D.; Ramstein, B.; Ritman, J.; Roderburg, E.; Salabura, P.; Sarantsev, A.; Basrak, Z.; Buehler, P.; Cargnelli, M.; Caplar, R.; Czerwiakowa, O.; Deppner, I.; Dzelalija, M.; Fodor, Z.; Gasik, P.; Gasparic, I.; Grishkin, Y.; Hartmann, O. N.; Hildenbrand, K. D.; Hong, B.; Kang, T. I.; Kecskemeti, J.; Kim, Y. J.; Kirejczyk, M.; Kis, M.; Koczon, P.; Kotte, R.; Lebedev, A.; Le Fevre, A.; Liu, J. L.; Manko, V.; Marton, J.; Matulewicz, T.; Piasecki, K.; Rami, F.; Reischl, A.; Ryu, M. S.; Schmidt, P.; Seres, Z.; Sikora, B.; Sim, K. S.; Siwek-Wilczynska, K.; Smolyankin, V.; Suzuki, K.; Tyminski, Z.; Wagner, P.; Weber, I.; Widmann, E.; Wisniewski, K.; Xiao, Z. G.; Yamasaki, T.; Yushmanov, I.; Zhang, Y.; Zhilin, A.; Zinyuk, V.; Zmeskal, J.
Abstract: We present the first determination of the N* resonances excitation functions with masses between 1650 MeV/c² and 1900 MeV/c² by means of a combined Partial Wave Analysis of seven exclusively reconstructed data samples for the reaction p+p -> pK+Λ measured by the COSY-TOF, DISTO, FOPI and HADES collaborations in fixed target experiments at kinetic energies between 2.14 and 3.5 GeV.

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Registration No. 25177 - Permalink

Comparison of two repository relevant archaea and their multistage bioassociation of uranium investigated with luminescence spectroscopy
Bader, M.; Swanson, J.; Drobot, B.; Steudtner, R.; Reed, D. T.; Stumpf, T.; Cherkouk, A.
Abstract: Microorganisms indigenous to rock salt must be considered for the safety analysis of a final repository for radioactive waste in a salt rock formation. Metabolic activity can cause microbial induced redox processes and influence radionuclide speciation and solubility. Additionally, passive biosorption onto living as well as dead biomass may affect the migration of radionuclides [1].
An extremely halophilic archaeon indigenous to rock salt was used for this study. Two similar strains with different origin were compared concerning their interaction processes with uranium. Halobacterium noricense DSM 15987 was originally isolated from an Austrian salt mine [2], the second strain Halobacterium putatively noricense was isolated from the Waste Isolation Pilot Plant (WIPP) [3].
[1] Lloyd, J. R. et al., Interactions of Microorganisms with Radionuclides (Eds. M. J. Keith-Roach, F. R. Livens), 313-342 (2002).
[2] Gruber, C. et al., Extremophiles, 8, Page 431-439 (2004).
[3] Swanson, J. S. et al., Status Report on the Microbial Characterization of Halite and Groundwater Samples from the WIPP - Status report Los Alamos National Laboratory, Page 1ff. (2012).
  • Lecture (Conference)
    ABC Salt V Actinide and Brine Chemistry in a Salt Repository Workshop (V), 26.-28.03.2017, Ruidoso, USA
Registration No. 25170 - Permalink

Computational modelling of flashing flows: a literature survey
Liao, Y.; Lucas, D.
Abstract: A review of published work on the physics and modelling of flashing flows is presented. The term “flashing” refers to a familiar phase change phenomenon initiated by pressure drop. It has gained a great deal of attention due to various industrial safety concerns. Nevertheless, knowledge about the involved physical processes such as formation and growth of bubbles in superheated liquid, and information for appropriate modelling in practical systems is still far from sufficiency. The present work is aimed to provide a brief but comprehensive overview of available theoretical models for these sub-phenomena as well as general modelling frameworks. This kind of review is necessary and helpful for further understanding and investigation of flashing flows in more detail.
Keywords: flashing flow; nucleation; coalescence and breakup; two-fluid model; poly-disperse

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  • Secondary publication expected from 07.04.2018
Registration No. 25164 - Permalink

Low CSC marker expression and low hypoxia identify good prognosis subgroups in HPV(-)HNSCC after postoperative radiochemotherapy: a multicenter study of the DKTK-ROG
Linge, A.; Löck, S.; Gudziol, V.; Nowak, A.; Lohaus, F.; von Neubeck, C.; Jütz, M.; Abdollahi, A.; Debus, J.; Tinhofer, I.; Budach, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Bayer, C.; Belka, C.; Pigorsch, S.; Combs, S. E.; Welz, S.; Zips, D.; Buchholz, F.; Aust, D. E.; Baretton, G. B.; Thames, H. D.; Dubrovska, A.; Alsner, J.; Overgaard, J.; Baumann, M.; Krause, M.; DKTK-RTOG
Abstract: Purpose: To investigate the impact of hypoxia-induced gene expression and cancer stem cell (CSC) marker expression on outcome of postoperative cisplatin-based radiochemotherapy (PORT-C) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC).

Experimental Design: Expression of the CSC markers CD44, MET, and SLC3A2, and hypoxia gene signatures were analyzed in the resected primary tumors using RT-PCR and nanoString technology in a multicenter retrospective cohort of 195 patients. CD44 protein expression was further analyzed in tissue microarrays. Primary endpoint was locoregional tumor control.

Results: Univariate analysis showed that hypoxia-induced gene expression was significantly associated with a high risk of locoregional recurrence using the 15-gene signature (P = 0.010) or the 26-gene signature (P = 0.002). In multivariate analyses, in patients with HPV16 DNA–negative but not with HPV16 DNA–positive tumors the effect of hypoxia-induced genes on locoregional control was apparent (15-gene signature: HR 4.54, P = 0.006; 26-gene signature: HR 10.27, P = 0.024). Furthermore, MET, SLC3A2, CD44, and CD44 protein showed an association with locoregional tumor control in multivariate analyses (MET: HR 3.71, P = 0.016; SLC3A2: HR 8.54, P = 0.037; CD44: HR 3.36, P = 0.054; CD44 protein n/a because of no event in the CD44-negative group) in the HPV16 DNA–negative subgroup.

Conclusions: We have shown for the first time that high hypoxia-induced gene expression and high CSC marker expression levels correlate with tumor recurrence after PORT-C in patients with HPV16 DNA–negative HNSCC. After validation in a currently ongoing prospective trial, these parameters may help to further stratify patients for individualized treatment de-escalation or intensification strategies. Registration No. 25163 - Permalink

3D matrix-based cell cultures: Automated analysis of tumor cell survival and proliferation
Eke, I.; Hehlgans, S.; Sandfort, V.; Cordes, N.
Abstract: Three-dimensional ex vivo cell cultures mimic physiological in vivo growth conditions thereby significantly contributing to our understanding of tumor cell growth and survival, therapy resistance and identification of novel potent cancer targets. In the present study, we describe advanced three-dimensional cell culture methodology for investigating cellular survival and proliferation in human carcinoma cells after cancer therapy including molecular therapeutics. Single cells are embedded into laminin-rich extracellular matrix and can be treated with cytotoxic drugs, ionizing or UV radiation or any other substance of interest when consolidated and approximating in vivo morphology. Subsequently, cells are allowed to grow for automated determination of clonogenic survival (colony number) or proliferation (colony size). The entire protocol of 3D cell plating takes ~1 h working time and pursues for ~7 days before evaluation. This newly developed method broadens the spectrum of exploration of malignant tumors and other diseases and enables the obtainment of more reliable data on cancer treatment efficacy.
  • International Journal of Oncology 48(2016)1, 313-321
Registration No. 25162 - Permalink

Comparison of toxicity and outcome in stage III NSCLC patients treated with IMRT or VMAT
Wijsman, R.; Dankers, F.; Troost, E. G. C.; Hoffmann, A. L.; Bussink, J.
  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl.1, S317
Registration No. 25161 - Permalink

beta1 Integrin/JNK Wechselwirkung im Glioblastom: Radiochemosensibilisierung und Invasionshemmung
Vehlow, A.; Klapproth, E.; Storch, K.; Matzke, D.; Cordes, N.
  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 75
Registration No. 25160 - Permalink

The potential of radiomics for radiotherapy individualization
Troost, E. G. C.; Pilz, K.; Löck, S.; Leger, S.; Richter, C. Registration No. 25159 - Permalink

Three-dimensional ECM-based cell culture models for cancer research
Storch, K.; Dickreuter, E.; Vehlow, A.; Cordes, N.
  • Abstract in refereed journal
    European Journal of Cancer 61(2016)Suppl.1, S74
Registration No. 25158 - Permalink

Gene signatures predict loco-regional control after postoperative radiochemotherapy in HNSCC
Schmidt, S.; Linge, A.; Lohaus, F.; Gudziol, V.; Nowak, A.; Tinhofer, I.; Budach, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Abdollahi, A.; Debus, J.; Belka, C.; Pigorsch, S.; Combs, S. E.; Mönnich, D.; Zips, D.; Baretton, G. B.; Buchholz, F.; Baumann, M.; Krause, M.; Löck, S. Registration No. 25157 - Permalink

MRI imaging of irradiated liver tissue for in vivo verification in particle therapy
Richter, C.; Duda, D. G.; Guimaraes, A. R.; Hong, T. S.; Bortfeld, T. R.; Seco, J.
  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl.1, S51-S52
Registration No. 25156 - Permalink

The variability of the RBE in proton therapy: can we base it on empirical clinical data?
Lühr, A.; von Neubeck, C.; Baumann, M.; Krause, M.
  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl. 1, S417
Registration No. 25155 - Permalink

Impact of tumour hypoxia and cancer stem cells on loco-regional control after primary radiochemotherapy in locally advanced HNSCC – results of a multicentre biomarker study of the German Cancer Consortium radiation Oncology Group
Linge, A.; Lohaus, F.; Löck, S.; Gudziol, V.; Nowak, A.; von Neubeck, C.; Tinhofer, I.; Budach, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Abdollahi, A.; Debus, J.; Bayer, C.; Belka, C.; Pigorsch, S.; Combs, S. E.; Mönnich, D.; Zips, D.; Baretton, G. B.; Buchholz, F.; Baumann, M.; Krause, M.
  • Abstract in refereed journal
    Oncology Research and Treatment 39(2016)Suppl.1, 22-23
Registration No. 25150 - Permalink

Tumour volume, hypoxia and cancer stem cells as prognosticators for LRC after primary RCT in HNSCC
Linge, A.; Lohaus, F.; Löck, S.; Gudziol, V.; Nowak, A.; von Neubeck, C.; Tinhofer, I.; Budach, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Abdollahi, A.; Debus, J.; Belka, C.; Pigorsch, S.; Combs, S. E.; Mönnich, D.; Zips, D.; Baretton, G. B.; Buchholz, F.; Baumann, M.; Krause, M. Registration No. 25149 - Permalink

Comparison of machine-learning methods for predictive radiomic models in locally advanced HNSCC
Leger, S.; Bandurska-Luque, A.; Pilz, K.; Zöphel, K.; Baumann, M.; Troost, E. G. C.; Löck, S.; Richter, C. Registration No. 25147 - Permalink

Hypoxie und Krebsstammzellmarker als Biomarker für die Radio(chemo)therapie von Kopf-Hals Plattenepithelkarzinomen
Krenn, C.; Linge, A.; Lohaus, F.; Löck, S.; Baumann, M.; Krause, M.
  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 121-122
Registration No. 25146 - Permalink

beta1-Integrin/c-Abl Interaktion reguliert DNA Reparatur und Strahlensensibilität humaner Tumorzellen
Koppenhagen, P.; Dickreuter, E.; Cordes, N.
  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 39
Registration No. 25145 - Permalink

Discoidin Domain Receptor 1 targeting impairs GBM cell invasion and mediates radiochemosensitization by induction of autophagy
Klapproth, E.; Vehlow, A.; Cordes, N.
  • Abstract in refereed journal
    European Journal of Cancer 61(2016)Suppl.1, S160-S161
Registration No. 25144 - Permalink

DDR1 reguliert Radiochemosensitivität sowie Invasivität humaner Glioblastomzellen
Klapproth, E.; Vehlow, A.; Cordes, N.
  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 42-43
Registration No. 25143 - Permalink

A Bayesian network model for acute dysphagia prediction in NSCLC patients
Jochems, A. T. C.; Deist, T. M.; Troost, E. G. C.; Dekker, A.; Faivre-Finn, C.; Oberije-Dehing, C.; Lambin, P.
  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl.1, S118-S119
Registration No. 25142 - Permalink

Re-Mining - Ressourcen aus Bergbauhalden
Büttner, P.; Gutzmer, J.
Abstract: Beitrag zum Tagungsband zur Veranstaltung "Economic Governance und Ordonomik 2016", welche in Halle im Festsaals des Siedehauses des Technischen Halloren- und Salinemuseums stattgefunden hat und auf der die Ergbnisse zum Projekt SMSB (Re-Mining) in einem Vortrag präsentiert wurden.
Keywords: Re-Mining, Halden, Tailings, Ressourcentechnologie, Resource, Rohstoffe, 3D-Model, GOCAD, Exploration, Processing, Aufbereitung, Erzgebirge, Tiefenbachhalde, Spülhalde, Davidschacht, Zero waste
  • Book chapter
    in: Economic Governance und Ordonomik: Die Nutzung von Ressourcen - mehr als eine ökonomische Fragestellung, Halle-Wittenberg: SPEEG, 2017, 978-3-86829-870-3, 213-225
Registration No. 25141 - Permalink

Targeting of beta1 integrins compromises DNA damage repair for radiosensitization of head and neck cancer cells
Dickreuter, E.; Eke, I.; Krause, M.; Borgmann, K.; van Vugt, M.; Cordes, N.
  • Abstract in refereed journal
    European Journal of Cancer 61(2016)Suppl.1, S1
Registration No. 25140 - Permalink

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