Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

"Online First" included
Without submitted and only approved publications
Only approved publications

32227 Publications
Windenergiepotential in Sachsen
Hirsch, W.; Rindelhardt, U.;
The wind energy ressources of Saxony, a typical interior state of Germany, have been estimated based on a special wind measuring programme. It was performed between 1991 and 1995. The main problem in applying the wind atlas method was to determine the areas with the same wind climate and the corresponding data sets (atlas stations). After defining the atlas stations ressource file calculations were performed over about 60 % of the saxon territory. The technical potential of wind energy in Saxony was estimated to be 5 TWh p.a. First results from saxon WEC`s confirm the results.
  • DEWI-Magazin Nr. 11, August 1997, S. 44 - 49

Publ.-Id: 904 - Permalink


Ermittlung bruchmechanischer Kennwerte im instrumentierten Kerbschlagbiegeversuch - Vergleichsuntersuchungen zur Rißdetektion mit Schallemission und dem Laserstreulichtverfahren
Richter, H.; Böhmert, J.; Valo, M.; Viehrig, H.-W.;
  • Lecture (Conference)
    Deutscher Verband für Materialforschung und -prüfung, Tagung Werkstoffprüfung 1997, Dezember 1997, Bad Nauheim, Vortragsband, S. 217 ff.
  • Contribution to proceedings
    Deutscher Verband für Materialforschung und -prüfung, Tagung Werkstoffprüfung 1997, Dezember 1997, Bad Nauheim, Vortragsband, S. 217 ff.

Publ.-Id: 903 - Permalink


Electron spectroscopy for chemical analysis Investigation of the Interaction of uranyl and calcium ions with humic acids
Nefedov, V. I.; Teterin, Y. A.; Lebedev, A. M.; Teterin, A. Y.; Dementjev, A. P.; Bubner, M.; Reich, T.; Pompe, S.; Heise, K.-H.; Nitsche, H.;
  • Inorganica Chimica Acta 273 (1998) 234-237

Publ.-Id: 902 - Permalink


Entwicklungen in der Technetiumchemie für die Nuklearmedizin
Johannsen, B.;
  • Nuclear Medizin 33 (1994) A 90 (Abstract)

Publ.-Id: 901 - Permalink


Theoretische Untersuchungen zur Fluid-Struktur-Wechselwirkung in zweiphasig durchströmten Schwingungsmodellen
Grunwald, G.;
Kurzfassung
Ausgehend von den Grundgleichungen für Kontinuität, Impuls und Energie einer Zweiphasenströmung werden Beziehungen für ein Ersatzfluid des Gas- Flüssigkeits- Gemisches mit orts- und zeitabhängiger Dichte und Geschwindigkeit aufgestellt und anhand eines Siedemodells geprüft. Es folgen Anwendungen auf ein 1D- und ein 2D- Schwingungsmodell (Pendel im Zweiphasenstrom) unter Berücksichtigung der Fluid-Struktur- Wechselwirkung und die Berechnung von Eigenfrequenzen und Dämpfungen.
  • Open Access LogoForschungszentrum Rossendorf; FZR-178 April 1997

Downloads:

Publ.-Id: 900 - Permalink


X-ray spectroscopy on ECR plasmas
Friedlein, R.; Herpich, S.; Lehnert, U.; Tyrroff, H.; Wirth, H.; Zippe, C.; Zschornack, G.;
  • Nuclear Instruments and Methods in Physics Research B 98 (1995) pp. 585-588

Publ.-Id: 899 - Permalink


Energy dispersive X-ray spectroscopy for ECR plasma diagnostics
Friedlein, R.; Küchler, D.; Zippe, C.; Zschornack, G.; Tyrroff, H.;
  • Hyperfine Interactions 99 (1996) pp. 225-234

Publ.-Id: 898 - Permalink


Experimental study of the hot and warm electron populations in an electron cyclotron resonance argon-oxygen-hydrogen plasma
Friedlein, R.; Herpich, S.; Hiller, H.; Wirth, H.; Zschornack, G.; Tyrroff, H.;
  • Physics of Plasmas 2 (1995) 6 pp. 2138-2140

Publ.-Id: 897 - Permalink


Hot and warm electron energy distribution at different electron cyclotron resonance ion source operation regimes
Friedlein, R.; Tyrroff, H.; Henke, D.; Zippe, C.; Zschornack, G.;
  • Review of Scientific Instruments 67 (1996) 3 pp. 1322-1324

Publ.-Id: 896 - Permalink


Characteristic x rays and electron energy distribution function in anisotropical hot plasmas
Friedlein, R.; Tyrroff, H.; Zippe, C.; Zschornack, G.; Barnitzke, W.;
  • Review of Scientific Instruments 67 (1996) 3 pp.1261-1263

Publ.-Id: 895 - Permalink


Electrical and optical characterisation of double SIMOX structures formed by sequential high energy oxygen implantation into silicon
Hatzopoulos, N.; Panknin, D.; Fukarek, W.; Skorupa, W.; Siapkas, D. I.; Hemment, P. L. F.;
  • Microelectronic Engineering 28 (1995) pp.415-418

Publ.-Id: 894 - Permalink


Ion optical system for transport and deceleration of highly charged ions
Henke, D.; Tyrroff, H.;
  • Review of Scientific Instruments 67 (1996) 3 pp. 1070-1072

Publ.-Id: 893 - Permalink


Ion-beam modification of ISFET membranes for copper ion detection
Hüller, J.; Pham, T.; Vopel, T.; Albrecht, J.;
  • Sensors and Actuators B 24-25 (1995) pp.225-227

Publ.-Id: 892 - Permalink


Role of hydrogen ions in plasma-enhanced chemical vapor deposition of hydrocarbon films, investigated by in situ ellipsometry
von Keudell, A.; Jacob, W.; Fukarek, W.;
  • Applied Physics Letters 66 (1995) 11 pp. 1322-1324

Publ.-Id: 891 - Permalink


Investigation of the damage induced by 200 keV Ge+ ion implantation in 6H-SiC
Pacaud, Y.; Skorupa, W.; Perez-Rodriguez, A.; Brauer, G.; Stoemenos, J.; Barklie, R.;
  • Nuclear Instruments and Methods in Physics Research B 112 (1996) pp. 321-324

Publ.-Id: 890 - Permalink


Ion beam sensitized SiO2 surface for halide ions
Pham, T.; Matz, W.; Möller, W.; Hüller, J.;
  • Analytica Chimica Acta 320 (1996) pp. 289-291

Publ.-Id: 889 - Permalink


Coimplantation of silver and halogens in thin SiO2 films
Pham, T.; Möller, W.; Hüller, J.; Albrecht, J.;
  • Journal of Applied Physics 79 (1996) 8 pp. 3915-3920

Publ.-Id: 888 - Permalink


Room-temperature, sorth-wavelength (400-500 nm) photoluminescence from silicon-implanted silicon dioxide films
Skorupa, W.; Yankov, R. A.; Tyschenko, I. E.; Fröb, H.; Böhme, T.; Leo, K.;
  • Applied Physics Letters 68 (1996) 17 pp. 2410-2412

Publ.-Id: 887 - Permalink


CEMS study on magnetic structure of Fe-Si-Al films implanted with Al and N ions
Nomura, K.; Reuther, H.; Richter, E.; Ujihira, Y.;
  • Contribution to proceedings
    ICAME '95, Conference Proceedings Vol. 50, Ed.: I. Ortalli, SIF Bologna, 1996, pp. 703-706

Publ.-Id: 886 - Permalink


Investigations of texture formation in geomaterials by neutron diffraction with high pressure chambers
Nikitin, A. N.; Sukhoparov, W. A.; Heinitz, J.; Walther, K.;
  • High Pressure Research 14 (1995) pp. 155-162

Publ.-Id: 885 - Permalink


Ion beam induced crystallization of 6H-SiC
Heera, V.; Kögler, R.; Skorupa, W.; Stoemenos, J.;
  • Book (Authorship)
    Institute of Physics Conference Series No 142: Chapter 3, pp. 533-536, Silicon Carbide and Related Materials 1995 Conf., Kyoto, Japan, c 1996 IOP Pub.

Publ.-Id: 884 - Permalink


High dose co-implantation of aluminium and nitrogen in 6H-silicon carbide
Heera, V.; Pezoldt, J.; Ning, X. J.; Pirouz, P.;
  • Book (Authorship)
    Institute of Physics Conference Series No 142: Chapter 3, pp. 509-512, Silicon Carbide and Related Materials 1995 Conf., Kyoto, Japan, c 1996 IOP Pub.

Publ.-Id: 882 - Permalink


Smooth termination of intruder bands in 10951Sb
Schnare, H.; La Fosse, D. R.; Hauschild, K.; Janzen, V. P.; Mullins, S. M.; Beausang, C. W.; de Graaf, J.; Lee, I. Y.; Afanasjev, A. V.;
  • Physical Review C 54 (1996) 4 pp. 1598-1609

Publ.-Id: 881 - Permalink


Nutzung genetischer Algorithmen zur Identifikation von Gesteinsschichten
Hoppe, D.; Schneider, S.;
  • Lecture (Conference)
    Berg- und Hüttenmännischer Tag, Freiberg, 1997, Tagungsbericht, S. 146-159
  • Contribution to proceedings
    Berg- und Hüttenmännischer Tag, Freiberg, 1997, Tagungsbericht, S. 146-159

Publ.-Id: 880 - Permalink


Evidence for Layered Structure of Boron Nitride Films Detected by Rutherford Backscattering
Plass, M.; Fukarek, W.; Kolitsch, A.; Mäder, M.; Möller, W.;
  • Physica Status Solidi A 155 (1996) pp. K1-K4

Publ.-Id: 879 - Permalink


Ion implantation and annealing effects in silicon carbide
Heera, V.; Skorupa, W.;
SiC is a promising semiconductor material for high-power/high-frequency
and high-temperature electronic applications. For selective doping of SiC
ion implantation is the only possible process. However, relatively little
is known about ion implantation and annealing effects in SiC. Compared
to ion implantation into Si there is a number of specific features which
have to be considered for successful ion beam processing of SiC. A brief
review is given on some aspects of ion implantation in and annealing of
SiC. The ion implantation effects in SiC are discussed in direct comparison
to Si. The following issues are addressed: ion ranges, radiation damage,
amorphization, high temperature implantation, ion beam induced crystallization
and surface erosion.
  • Materials Research Society symposium proceeding 438 (1997) pp. 241-252, MRS

Publ.-Id: 877 - Permalink


Quantum-sized silicon precipitates in silicon-implanted and pulse-annealed silicon dioxide films: Photoluminescence and structural transformations
Tyschenko, I. E.; Kachurin, G. A.; Zhuravlev, K. S.; Pazdnikov, N. A.; Volodin, V. A.; Gutakovsky, A. K.; Leier, A. F.; Fröb, H.; Leo, K.; Böhme, T.; Rebohle, L.; Yankov, R. A.; Skorupa, W.;
Strong blue, red an near-infrared photoluminescence has
been observed from Si+-implanted and pulse annealed SiO2 layers. Raman
scattering and high-resolution electron microscopy analyses have revealed
a correlation between the structure of the Si inclusions in the SiO2 layers
during pulse and furnace annealing have been discussed in terms of the
changes in the light emission ovserved experimentally. Small Si clusters,
non-crystallineinclusions and nanocrystals are believed to be the light
sources. The blue, red and near-infrared photoluminescence is associated
with small complexes of excess Si atoms, non-crystalline Si nanoinclusters
and quantum-confined Si nanocrystals, respectively.
  • Contribution to proceedings
    Materials Research Society symposium proceeding 438 (1997) pp. 453-458, MRS

Publ.-Id: 876 - Permalink


Implantation and growth of large Beta-FeSi2 precipitates and Alpha-FeSi2 network structures in silicon
Reuther, H.; Dobler, M.;
  • Applied Physics Letters 69 (1996) 21 pp. 3176-3178

Publ.-Id: 874 - Permalink


Verfahren der Ionenstrahlbearbeitung und ihre Anwendung bei Umformwerkzeugen
Richter, E.;
Ionenstrahltechniken können mit Erfolg zur Verbesserung der Standmengen bei Umformwerkzeugen eingesetzt werden. Am Beispiel der Stickstoffionenimplantation konnte gezeigt werden, dass fü die Umformung weicher Materialien bei Press-, Stanz- und Ziehwerkzeugen eine Verläerung der Einsatzdauer bei Produktionswerkzeugen unter industriellen Bedingungen bis zum Faktor 4 erreichbar ist. Vorteilhaft ist eine gezielte Bearbeitung der verschleissgefährdeten Regionen eines Werkzeuges mit Hilfe eines gerichteten Ionenstrahls. Neben der unmittelbaren Implantation bietet die ionenstrahlgestüzte Beschichtung als Kombination von konventioneller PVD-Beschichtung und Ionenimplantation eine Vielzahl technisch interessanter Mölichkeiten auch fü Umformwerkzeuge.
  • Blech Rohre Profile 43 (1996) 4 pp. 191-194

Publ.-Id: 873 - Permalink


Formation of buried layers of (SiC)1-x(AlN)x in 6H-SiC using ion-beam synthesis
Yankov, R. A.; Hatzopoulos, N.; Fukarek, W.; Voelskow, M.; Heera, V.; Pezoldt, J.; Skorupa, W.;
Solid solutions of SiC and III-V compound semiconductors
are recognized as promising materials for novel semiconductor applications.
This paper reports on experiments which explore the possibility of synthesizing
thin buried layers of (SiC)1-x(AlN)x having composition of about x = 0.2
by co-implanting N+ and Al+ ions into 6H-SiC-wafers maintained at temperatures
in the range 200 - 800 C. Structural and compositional evaluation of as-implanted
samples was carried out using a combination of Rutherford backscattering/channelling
spectrometry and infrared reflectance spectroscopy. It is shown that the
structures are highly sensitive to the substrate temperature. The use of
sufficiently high temperatures (400 - 800 C) enables the crystallinity
of the host material as well as relatively low damage levels to be maintained
during implantation. The formation of Al-N bonds within the implanted layers
is also confirmed over the temperature range studied.
  • Contribution to proceedings
    Materials Research Society symposium proceeding 438 (1997) pp. 271-276, MRS

Publ.-Id: 872 - Permalink


Institute of Ion Beam Physics and Materials Research; Annual Report 1996
von Borany, J.; Jäger, H.-U.; Möller, W.; Wieser, E.;
  • Open Access LogoForschungszentrum Rossendorf; FZR-166

Downloads:

Publ.-Id: 871 - Permalink


Lifetimes of a shears band in139Sm
Brandolini, F.; Ionescu-Bujor, M.; Medina, N. H.; Ribas, R. V.; Bazzacco, D.; de Poli, M.; Pavan, P.; Alvarez, C. R.; de Angelis, G.; Lunardi, S.; von Acuna, D.; Napoli, D. R.; Frauendorf, S.;
  • Physics Letters B 388 (1996) pp. 468-474

Publ.-Id: 870 - Permalink


Total and nuclear fission cross sections of 238U at relativistic energies
Rubehn, T.; Bassini, R.; Begemann-Blaich, M.; Blaich, T.; Immé, G.; Möhlenkamp, T.; Moretto, L. G.; Schüttauf, A.; Seidel, W.; Trzcinski, A.;
  • Other report
    GSI-Preprint-96-11, März 1996
  • Physical Review C 53 (1996) pp.3143-3146

Publ.-Id: 869 - Permalink


Application of 13C-labelled polychlorinated biphenyl congener 153 as internal standard in the gas chromatogrophic-mass spectrometric analysis of polychlorinated biphenyls
Kubátová, A.; Matucha, M.; Bubner, M.;
  • Journal of Chromatography A 750 (1996) pp. 245-251

Publ.-Id: 868 - Permalink


Shape of a Co-Nd Liquid Alloy Ion Source
Hesse, E.; Driesel, W.; Dietzsch, C.; Bischoff, L.; Teichert, J.;
Co-Nd-liquid alloy ion sources (LAIS) were operated of a special specimen holder in situ in a 1 MeV transmission electron microscope. The dynamics of the tip shape in dependence of the ion emission current, spatial shifts of the liquid cone and the process of double cone formation have been observed. This results in a bette understanding of the ion emission processes from Co-Nd-LAISs in a large range of ion current. A linear dependence of the decrease of the cone half angle and of the jet lenght l and of the diameter d on the increased ion emission current was found. No emission of microdroplets at the shanks of the Taylor cone and behind the cone has been detected.
  • Japanese Journal of Applied Physics Part 1 35 (1996) 10 pp. 5564-5570

Publ.-Id: 867 - Permalink


The Rossendorf 3 MV tandetron: a new generation of high-energy implanters
Friedrich, M.; Bürger, W.; Henke, D.; Turuc, S.;
  • Nuclear Instruments and Methods in Physics Research A 382 (1996) pp. 357-360

Publ.-Id: 866 - Permalink


Synthesis and Structural Characterization of Neutral Oxorhenium(V) Complexes with Tridentate Dithioethers
Pietzsch, H.-J.; Reisgys, M.; Spies, H.; Leibnitz, P.; Johannsen, B.;
  • Chemische Berichte 130 (1997) pp. 357-361

Publ.-Id: 865 - Permalink


Production and decay of hot nuclei following antiproton annihilation at rest and in flight
Jahnke, U.; Bohne, W.; Eades, J.; von Egidy, T.; Figuera, P.; Fuchs, H.; Galin, J.; Goldenbaum, F.; Gulda, K.; Golubeva, Y. S.; Hartmann, F. J.; Hilscher, D.; Iljinov, A. S.; Jastrzebski, J.; Kurcewicz, W.; Lott, B.; Morjean, M.; Pausch, G.; Péghaire, A.; Pienkowski, L.; Polster, D.; Proschitzki, S.; Quednau, B.; Rossner, H.; Schmid, S.; Schmid, W.;
  • Jadernaja fizika 59 (1996) 9 pp, 1625-1634

Publ.-Id: 864 - Permalink


Fabrication of MSM detector structures on silicon by focused ion beam implantation
Teichert, J.; Bischoff, L.; Hausmann, S.;
We report the fabrication of metal-semiconductor-metal
(MSM) photo detectors on silicon substrates with CoSi2 electrodes. The
electrode patterns have been formed by ion beam synthesis applying maskless
implantation with a cobalt focused ion beam. Implantation has been carried
out with the substrate at room temperature and at 400 °C.
  • Microelectronic Engineering 35 (1997) pp. 455.458

Publ.-Id: 863 - Permalink


Test of scintillating-fiber calorimeter for photons with energies below 1 GeV
Hübner, B.; Brinkmann, K.-T.; Freiesleben, H.; Lange, J. S.; Naumann, B.; Naumann, L.; Schülke, A.;
  • Nuclear Instruments and Methods in Physics Research A 382 (1996) pp.413-418

Publ.-Id: 862 - Permalink


Evolution of nanocluster ensembler: Computer simulation of diffusion and reaction controlled Ostwald ripening
Strobel, M.; Reiß, S.; Heinig, K.-H.;
The Ion Beam Synthesis (IBS) of nanoclusters can be controlled by the flux and the fluence of ions as well as by the implantation and/or annealing temperature. The evolution of the precipitates, mainly described by their particle radius distribution (PRD), the number of remaining particles and the critical radius, depends on these parameters. However, the evolution is expected to behave different for systems like SiO2 and CoSi2 clusters in Si, because they are characterized by quite different ratios of diffusion to reaction constants. Here we present an unified model of Ostwald ripening of nanoclusters, which describes the pure diffusion and reaction controlled limits as well as all intermediate, mixed processes. Expressing the exact solution of the adiabatic diffusion equation by multipole moments we derive the governing equation for the evolution of an ensemble of nanoclusters in the leading monopole approximation. Whereas in the diffusion controlled regime we have the well known infinite range 1/r interaction among the nanoclusters, 1/r2 interactions come into play in the reaction limited regime. Computer simulations for ensembles of several thousands of nanoclusters demonstrate the evolution for typical cases.
  • Nuclear Instruments and Methods in Physics Research B 120 (1996) pp. 216-220

Publ.-Id: 861 - Permalink


Mathematisch-numerische Modellierung der Ultraschallstreuung an oberflächenverbundenen Rissen mit dem EFIT-Code
Bergmann, U.; Bergner, F.;
Abstract
An ultrasonic time-of-flight diffraction method for measuring stable crack growth in a three point bending specimen was analyzed by simulations of the wave field evolution in the test specimen. To calculate the actual crack length from the experimental measured time of flight of a crack tip diffracted ultrasound pulse the echo trains were successively measured during the whole bending test. The simulations deal with the generation and evolution of the ultrasound field in the specimen and with the design of the received signal. The simulations took into account the actual test geometry, the crack growth process, the blunted crack tip and the process of bending. With these simulations all individual received echoes are reproduced and interpreted. The echo, qualified for measuring the time of flight is undoubtedly the transverse wave diffracted on the crack tip. In order to optimize the test method and to increase the accuracy of measurements during the simulations Parameters like probe position, wave mode, measuring frequency and length of aperture of the probes wem separately varied. From the comparison between the simulations and the experimental measurements it can be concluded, that the developed method is weil suited for measuring stable crack growth in small specimens made from ductile material.
  • Open Access LogoForschungszentrum Rossendorf; FZR-177 1997

Downloads:

Publ.-Id: 859 - Permalink


Nachweis verformungsbedingter Strukturschädigung in Rißnähe durch Röntgenkleinwinkelstreuung
Böhmert, J.; Große, M.;
  • Lecture (Conference)
    29. DVM-Tagung Bruchvorgänge, Februar 1997, Stuttgart, S. 299 ff.
  • Contribution to proceedings
    29. DVM-Tagung Bruchvorgänge, Februar 1997, Stuttgart, S. 299 ff.

Publ.-Id: 857 - Permalink


Detection of metastable defective regions in ion-implanted Silicon by means of metall gettering
Kögler, R.; Posselt, M.; Yankov, R. A.; Kaschny, J.; Mücklich, A.; Skorupa, W.; Danilin, A. B.;
  • Lecture (Conference)
    MRS '97, Spring Meeting, San Francisco, March 31-April 4, 1997

Publ.-Id: 856 - Permalink


Methode zur schnellen Bestimmung von Actiniden in Bauschutt zur Freigabeentscheidung
Nebelung, C.; Nitsche, H.; Bernhard, G.;
  • Lecture (Conference)
    V. Stillegungskolloquium, 24./25.6.1997 in Hannover
  • Contribution to external collection
    IV. Statusbericht Stillegung und Rückbau kerntechnischer Anlagen, S. 293-301

Publ.-Id: 855 - Permalink


EXAFS Investigations of the Interaction of Humic Acids and Model Compounds with Uranyl Cations in Solid Complexes
Denecke, M. A.; Reich, T.; Bubner, M.; Heise, K.-H.; Nitsche, H.; Allen, P. G.; Bucher, J. J.; Edelstein, N. M.; Shuh, D. K.;
  • Lecture (Conference)
    MIGRATION '97, Konferenz vom 26.-31. Oktober 1997 in Sendoi, Japan

Publ.-Id: 854 - Permalink


Determination of Structural Parameters od Uranyl Ions Complexed with Organic Acids using EXAFS
Denecke, M. A.; Reich, T.; Bubner, M.; Pompe, S.; Heise, K.-H.; Nitsche, H.; Allen, P. G.; Bucher, J. J.; Edelstein, N. M.; Shuh, D. K.;
  • Lecture (Conference)
    ACTINIDES '97, 21.-26. September 1997 in Baden-Baden

Publ.-Id: 853 - Permalink


Validation of complex formation of CA2+; UO22+ and CO32-
Bernhard, G.; Brendler, E.; Geipel, G.; Reich, T.; Nitsche, H.;
  • Poster
    MIGRATION '97, Konferenz vom 26.-31. Oktober 1997 in Sendoi, Japan
  • Poster
    Euroconference and NEA Workshop: Actinide-XAS-98, Grenoble, France, 04.-06.10.1998

Publ.-Id: 852 - Permalink


Complex formation between UO22+ and CO32- studied by Laser-Induced photoacoustic Spectroscopy
Geipel, G.; Bernhard, G.; Brendler, V.; Nitsche, H.;
  • Lecture (Conference)
    MIGRATION '97, Konferenz vom 26.-31. Oktober 1997 in Sendoi, Japan
  • Radiochimica Acta 82, 59 (1998)

Publ.-Id: 851 - Permalink


Convective, absolute and global instabilities of thermocapillary-buoyancy convection in extended layers, Page Number 4187
Priede, J.; Gerbeth, G.;
  • Physical Review E, 10/31/97, October 1997, pp. 4187 - 4199

Publ.-Id: 849 - Permalink


Sorption of Uranium(VI) onto Phyllite
Arnold, T.; Zorn, T.; Bernhard, G.; Nitsche, H.;
  • Chemical Geology 151(1998) 129-141
  • Lecture (Conference)
    Workshop: The Münster Workshop on Mineral Surface Science, Münster, Germany, 18.-20.03.1998
  • Lecture (Conference)
    Workshop: Surface Reactivity Meeting, University of Manchester, Department of Earth Sciences, Manchester, UK 30.03.-01.04. 1998

Publ.-Id: 848 - Permalink


Neutral Oxorhenium(V) and Oxotechnetium(V) Complexes with a novel Amide Thiother Dithiolate Ligand derived from Cysteine
Noll, B.; Hilger, C. S.; Spies, H.; Leibnitz, P.; Dinkelborg, L.; Johannsen, B.;
  • Lecture (Conference)
    Chemische Berichte, COST-Meeting, Jülich, 13.-14.11.1997

Publ.-Id: 847 - Permalink


Effects of irradiation and annealing on the microstructure of Russian VVER-440-type reactor pressure vessel steels
Große, M.; Böhmert, J.;
  • Lecture (Conference)
    International conference PLIM + PLEX 1997, Prague

Publ.-Id: 846 - Permalink


The structure of 113Sn from proton and alpha-particle induced reactions
Käubler, L.; Lobach, Y. N.; Trishin, V. V.; Pasternak, A. A.; Kudojarov, M. F.; Prade, H.; Reif, J.; Schwengner, R.; Winter, G.; Blomqvist, J.; Döring, J.;
The result of in-beam investigation of 113Sn using the (p,n),
(p,3n), (alpha,n) and (alpha,2n) reactions are summarized. Excited states
have been identified until Ex=4715 MeV and JPi=(27/2-).
For a large number of levels mean lifetimes tau have been determined with
the DSA method. For the JPi=25/2+ state at Ex=4059
MeV, tau=1.0(4) ns has been measured with the gamma-RF method. The experimental
results are compared with the predictions of shell-model calculations.
Most of the positive-parity states may be considered as one- or three-quasiparticle
neutron excitations of the 2d5/2, 1g7/2, 3s1/2
and 2d3/2 shells, the negative-parity states asthe coupling
of one 1h11/2 neutron to the two- or four-quasiparticle neutron
excitations in even-mass 112Sn core. For the 25/2+
isomer the three-quasiparticle neutron configuration v(h211/2g-17/2)
has been proposed on the basis of a shell-model analysis using the mass-formula
formalism. The experimentally observed yrast states in 11350Sn63
are compared with the corresponding states in the valence mirror nucleus
14563Eu82 giving remarkable similarities
although the parameters for the shell-model calculations differ considerably.
The analysis of nearest.neighbour spacing distributions of experimentally
obtained 5/2+ states in 113Sn does not allow definite
conclusions about regularity or chaos.
  • Zeitschrift für Physik A 358, 303-315 (1997)

Publ.-Id: 845 - Permalink


Resolution-enhanced spectroscopy of 81Y
Schnare, H.; Winter, G.; Käubler, L.; Reif, J.; Schwengner, R.;
The fusion-evaporation reaction 58Ni(32S,2 alpha
p ) has been used to study the neutron-deficient isotope 81Y.
Multiple particle gamma-ray coincidences have been detected by the GAMMASPHERE
array combined with the MICROBALL chrged-particle detector system. Gamma-ray
spectra with an improved resolution have been achieved from an event-by-event
determination of the nucleus recoil momentum, thus allowing a precise Doppler-shift
correction. In this way a resolution enhancement by a factor 2 was obtained
for a 1 MeV gamma line. During the analysis an Egamma - Egamma
matrix as well as an Egamma - Egamma - Egamma
cube have been used to extend the previously known level scheme to higher
spin ( I ca. 57/2 ) and excitation energy ( Ex ca. 17 MeV ).
More than 100 new gamma rays and 80 new levels have been added to the level
scheme and six new bands have been established. The interpretation of these
bands in terms of the cranking model and their comparison with similar
bands in neighboring nuclei is discussed.
  • Physical Review C Volume 56, Number 2, 729-743

Publ.-Id: 844 - Permalink


Ionenstrahlinduzierte Wachstumsprozesse amorpher Schichten in Silicium
Henkel, T.;
  • Open Access LogoForschungszentrum Rossendorf; FZR-175 (Dissertation TU Dresden); März 1997

Downloads:

Publ.-Id: 843 - Permalink


Accumulation of U(VI) by Microorganisms Recovered from Uranium Mining Waste Pile
Panak, P.; Bernhard, G.; Kutschke, S.; Otto, A.; Röske, K.; Selenska-Pobell, S.; Barth, G.; Nitsche, H.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 842 - Permalink


Model investigations of aqueous UO2 2+/Ca 2+/humic acid complexation
Bubner, M.; Pompe, S.; Jander, R.; Heise, K.-H.; Nitsche, H.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 841 - Permalink


Thermochromatographic Adsorption Studies - an Approach to Metallic State Properties of the Heaviest Actinides
Hübener, S.; Taut, S.; Eichler, B.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 840 - Permalink


Thermochromatography of No-259
Taut, S.; Hübener, S.; Eichler, B.; Gäggeler, H. W.; Timokhin, S. N.; Zvara, I.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 839 - Permalink


Interaction of uranium(VI) with silicic acid in aqueous solutions by time-resolved laser-induced fluorescence spectroscopy (TRLFS)
Moll, H.; Geipel, G.; Brendler, V.; Bernhard, G.; Nitsche, H.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden
  • J. Alloys and Compounds 271-273, 765 (1998)

Publ.-Id: 838 - Permalink


A fast method for low-level actinide measurement in concrete
Nebelung, C.; Nitsche, H.; Bernhard, G.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden
  • J. Alloys and Compounds 271-273, 42 (1998)

Publ.-Id: 837 - Permalink


Uranium speciation in waters of different uranium mining areas
Bernhard, G.; Geipel, G.; Brendler, V.; Nitsche, H.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden
  • J. AlloysCompounds 271-273, 201 (1998)

Publ.-Id: 836 - Permalink


Uranyl carbonate complexes studied by Laser-Induced Spectroscopy
Geipel, G.; Bernhard, G.; Brendler, V.; Nitsche, H.;
  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 835 - Permalink


Self-Consistent Pushing and Cranking Corrections to the Meson Fields of the Chiral Quark-Loop Soliton
Schleif, M.; Wünsch, R.; Meissner, T.;
We study translational and spin-isospin symmetry restoration for the two-flavor chiral quark-loop soliton. Instead of a static soliton at rest we consider a boosted and rotating hedgehog soliton. Corrected classical meson fields are obtained by minimizing a corrected energy functional which has been derived by semi-classical methods ('variation after projection').
We evaluate corrected meson fields in the region 300 <= M <= 600 of constituent quark masses M and compare them with the uncorrected fields. We study the effect of the corrections on various expectation values of nuclear observables such as the root-mean square radius, the axial-vector coupling constant, magnetic moments and the delta-nucleon mass splitting.
  • Open Access LogoForschungszentrum Rossendorf; FZR-173 Preprint
  • International Journal of Modern Physics E, Vol. 7, No. 1 (February 1998) 121-138

Downloads:

Publ.-Id: 834 - Permalink


Aufbau eines behördlichen Fernüberwachungssystems zur betrieblichen Überwachung des KKW Saporoshje (Block 5), 3. Realisierungsstufe
Beyer, M.; Carl, H.; Nowak, K.; Schumann, P.; Seidel, A.;
The report gives an overview of the further development of the remote monitoring system for the Ukrainian nuclear power plant Zaporozh'ye. The proposals for concept, structure and algorithmic design of the user software elaborated by Research Centre Rossendorf and TÜV Rheinland are presented and explained complemented by a short description of the conversion of the German proposals into the user´s software by the State Scientific-Technical Centre of the Ukrainian Supervisory Authority. Furthermore, there is an actual information about the operational use of the components of the monitoring system in the Zaporozh'ye NPP. The realization efforts for the completion of the NPP-site system and for the integration of the Kiev Centre into the system close the report. The industrial testing phase of the system was started in June of 1996. Since then, supervisory authority and operator have been able to fulfil their monitoring duties more efficiently than before by direct access to the actual operational data.
  • Open Access LogoForschungszentrum Rossendorf; FZR-174 März 1997

Downloads:

Publ.-Id: 833 - Permalink


Detection of Aerosol Losses in Glass Vessels
Rettig, D.; Merker, P.; Nitsche, H.;
  • Poster
    European Aerosol Conference, 15.-19. Sept. 1997, Hamburg, Germany
  • Journal of Aerosol Science, Vol. 28, Suppl. 1,pp. S139-S140, 1997

Publ.-Id: 832 - Permalink


Density and structural changes of SiC after amorphization and annealing
Heera, V.; Prokert, F.; Schell, N.; Seifarth, H.; Fukarek, W.; Voelskow, M.; Skorupa, W.;
The density of amorphous SiC layers formed by 2 MeV Si+ implantation into single crystalline 6H-SiC was measured by X-ray reflectometry and compared with the resultts of step height measurements. Reactive ion
etching was used to investigate the density as function of depth. The density of the as-amorphized SiC is about 12 % less than that of the crystalline material. Within the experimental accuracy the density reduction is homogeneous
over the whole layer thickness. Low temperature annealing leads to the formation of relaxed amorphous SiC with a density about 7 % below the crystalline one. These large density changes are in contrast to results in amorphous
Si. They can be explained by the high atomic density of SiC and the chemical disorder in the amorphous state of SiC.
  • Applied Physics Letters 70(26), 3531

Publ.-Id: 831 - Permalink


Hot and dense pion gas with finite chemical potential
Kolomeitsev, E. E.; Voskresensky, D. N.; Kämpfer, B.;
  • Acta Physica Polonica B 27 (1996) 11 pp. 3263-3270

Publ.-Id: 829 - Permalink


The response of the Euroball Cluster detector to gamma-radiation up to 10 MeV
Wilhelm, M.; Eberth, J.; Pascovici, G.; Radermacher, E.; Thomas, H. G.; von Brentano, P.; Prade, H.; Lieder, R. M.;
  • Nuclear Instruments and Methods in Physics Research A 381 (1996) pp. 462-465

Publ.-Id: 828 - Permalink


Lineshape, linewidth and spectral density of parametric x-radiation at low electron energy in diamond
Freudenberger, J.; Genz, H.; Morokhovskii, V. V.; Richter, A.; Morokhovskii, V. L.; Nething, U.; Zahn, R.; Sellschop, J. P. F.;
  • Applied Physics Letters 70 (1997) 2 pp. 267-269

Publ.-Id: 827 - Permalink


Characteristic features of the lineshape in the spectrometry of ions using Si detectors
Ilyashenko, I. N.; Strokan, N.; Schmidt, B.;
A model which explains the characteristic distortions of the spectral lineshape of a Si detector during the recording of heavy ions is proposed. The appearence of a group of pulses in the right-hand (high-energy) region of the amplitude spectrum is associated with nonequilibrium-charge recombination. The recombination occurs in the skin layer of the detector structure, where charge transfer occurs by diffusion. The amplitude of the signal fluctuates because of the participation of Si recoil atoms, which generate electron-hole pairs at specific cross sections of the "input-window" of the detector. Heavy particles directly produce ionization uniformly over depth, which results in definite losses of charge but is not accompanied by appreciable fluctuations.
  • Semiconductors 30 (1996) 12 pp. 1158-1161

Publ.-Id: 826 - Permalink


Rißfortschrittsmessung an Dreipunkt-Biegeproben mit Ultraschall
Bergmann, U.; Bergner, F.; Böhmert, J.;
Ein Ultraschall-Laufzeit-Beugungsverfahren wurde zur Messung des Rißfortschritts im quasistatischen Dreipunkt-Biegeversuch an Proben unterschiedlicher Werkstoffe eingesetzt. Der mit diesem Verfahren bestimmte Gesamtrißfortschritt steht in guter Übereinstimmung mit dem jeweiligen fraktografisch bestimmten Wert.
Durch eine geeignete Darstellungsweise der Ultraschallsignale konnte die Aussagekraft der Messungen deutlich erhöht werden. Insbesondere für Gußeisen zeigt sich ein ausgeprägter Übergang von Rißspitzenabstumpfung zu Rißausbreitung. Durch Ausnutzen der Bildinformationen kann der Rißfortschritt auch dann gemessen werden, wenn das Rißspitzenecho durch ein anderes Echo überlagert wird.
Es wurde gezeigt, daß Rißfortschrittsmessungen prinzipiell auch auf der Grundlage von rißspitzengebeugten Longitudinalwellen möglich ist.
  • Lecture (Conference)
    Werkstoffprüfung '96, 5.-6.12.1996, Bad Nauheim, Deutscher Verband für Materialforschung und -prüfung e.V.
  • Contribution to proceedings
    Vortrags- und Diskussionstagung "Werkstoffprüfung 1996", 5.-6.12.96, Bad Nauheim, Tagungsband S. 143-151

Publ.-Id: 825 - Permalink


Freeze-Out Time in Ultrarelativistic Heavy Ion Collisions from Coulomb Effects in Transverse Pion Spectra
Barz, H.-W.; Bondorf, J. P.; Gaardhoje, J. J.; Heiselberg, H.;
Abstract:
The influence of the nuclear Coulomb field on transverse spectra of λ + and λ- measured in Pb + Pb reactions at 158 A GeV has been investigated. Pion trajectories are calculated in the field of an expanding fireball. The observed enhancement of the λ-+ ratio at small momenta depends on the temperature and transverse expansion velocity of the source, the rapidity distribution of the net positive charge, and mainly the time of the freeze-out.
  • Physical Review C 56, No. 3, September 1997, 1553-1556
  • Open Access LogoForschungszentrum Rossendorf; FZR-168 Preprint

Downloads:

Publ.-Id: 824 - Permalink


Ladungsverteilungen und kollektives Verhalten in 197Au + 197Au - Stößen bei Eprog = 150 bis 1000 A MeV
Biegansky, J.;
  • Other report
    Dissertation

Publ.-Id: 823 - Permalink


Institute of Bioinorganic and Radiopharmaceutical Chemistry; Annual Report 1996
Johannsen, B.; Seifert, S.;
  • Open Access LogoForschungszentrum Rossendorf; FZR-165

Downloads:

Publ.-Id: 822 - Permalink


Analytische Modellierung mechanischer Schwingungen von Primärkreiskomponenten des Druckwasserreaktors WWER-440 mit finiten Elementen
Altstadt, E.; Grunwald, G.; Scheffler, M.; Weiß, F.-P.;
The project contributes to the improved evaluation of the mechanical integrity of the soviet-type VVER-440 reactors especially, to a sensitive early failure detection and to the localization of mechanical damages of reactor components by means of vibration monitoring. For that purpose the mechanical vibration of all primary circuit
components was modelled by finite elements. Modeling was built on the finite element code ANSYS. The interaction between the coolant flowing in the downcomer and the vibrating components has been considered by a fluid-structure element, which describes additional mode selective damping and intertia due to the coolant displacement when the downcomer geometry changes. The calculation model was adjusted using results from experimental vibration investigations. To some extent data from earlier measurements were available. But additionally dedicated experiments had to be performed at original VVERs. Now, the model can be regarded to be widely verified. Mainly it was applied to clarify how hypothetical damages of reactor internals influence the vibration signature of the primary circuit. Such kind of damage simulation is an appropriate means to find sensitive measuring positiones for on-line monitoring and to define physically based threshold values. In principle, the model is even suited to estimate the loads of reactor components which might be imposed by external events (explosion, earthquake).
  • Open Access LogoForschungszentrum Rossendorf; FZR-172 April 1997

Downloads:

Publ.-Id: 821 - Permalink


Kaonen in Kernmaterie
Kolomeitsev, E. E.;
  • Open Access LogoForschungszentrum Rossendorf; FZR-167

Downloads:

Publ.-Id: 820 - Permalink


Correlations between resonances in a statistical scattering model
Gorin, T.; Dittes, F.-M.; Müller, M.; Rotter, I.; Seligman, T. H.;
Abstract
The distortion of the regular motion in a quantum system by its coupling to the continuum of decay channels is investigated. The regular motion is described by means of a Poissonian ensemble. We focus on the case of only few channels K < 10. The coupling to the continuum induces two main effects, due to which the distorted system differs from a chaotic system (described by a Gaussian ensemble): 1. The width distribution for large coupling becomes broader than the corresponding Χ2K distribution in the GOE case. 2. Due to the coupling to the continuum, correlations are induced not only between the positions of the resonances but also between positions and widths. These correlations remain even in the strong coupling limit. In order to explain these results, an asymptotic expression for the width distribution is derived for the one channel case. It relates the width of a trapped resonance state to the distance between its two neighboring levels.
  • Open Access LogoForschungszentrum Rossendorf; FZR-162 Preprint
  • Physical Review E 56, (1997), 2481-2491

Downloads:

Publ.-Id: 819 - Permalink


Proton-Proton Correlations in Central Collisions of Ni+Ni at 1.93 A GeV and the Space-Time Extent of the Emission Source
Kotte, R.; Biegansky, J.; Mösner, J.; Neubert, W.; Plettner, C.; Wohlfarth, D.; Alard, J. P.; Amouroux, V.; Basrak, Z.; Bastid, N.; Belyaev, I.; Berek, G.; Best, D.; Buta, A.; Caplar, R.; Cindro, N.; Coffin, J. P.; Crochet, P.; Dona, R.; Dupieux, P.; Dzelalija, M.; Eskef, M.; Fintz, P.; Fodor, Z.; Fraysse, L.; Genoux-Lubain, A.; Göbels, G.; Gobbi, A.; Guillaume, G.; Häfele, E.; Herrmann, N.; Hildenbrand, K. D.; Hölbling, S.; Hong, B.; Jundt, F.; Kecskemeti, J.; Kirejczyk, M.; Korolija, M.; Kuhn, C.; Lebedev, A.; Legrand, I.; Leifels, Y.; Maazouzi, C.; Manko, V.; Merlitz, H.; Mohren, S.; Pelte, D.; Petrovici, M.; Pinkenburg, C.; Pras, P.; Rami, F.; Reisdorf, W.; Ritman, J. L.; Roy, C.; Schüll, D.; Seres, Z.; Sikora, B.; Simion, V.; Siwek-Wilczynska, K.; Sodan, U.; Somov, A.; Tizniti, L.; Trzaska, M.; Vasiliev, M. A.; Wagner, P.; Wang, G. S.; Wienold, T.; Yatsunenko, Y.; Zhilin, A.;
Abstract.

Small-angle correlations of Proton pairs produced in central Ni+Ni collisions at a beam energy of 1.93 AGeV are investigated with the FOPI detector System at GSI Darmstadt. A well-defined emission source is selected by triggering on central events which comprise about 8% of the total cross section. Simultaneous comparison of longitudinal and transverse correlation functions with the predictions of the Koonin model allows to unravel the space-time ambiguity of the emission process. Taking into account the strong collactive expansion of the participant zone, which introduces a reduction of the extracted source radius of more than 30% r.m.s. radius and emission time parameters of Rrms = ( 4.2 ± 1.2) fm and trms = (11+7-5) fm/c are extracted, respectively. In contrast, the analysis of the angle-integrated correlation function gives an upper limit Rrms = (7.0 ± 1.4) fm of the source radius.
  • Zeitschrift für Physik A 359, (1997) 47-54
  • Open Access LogoForschungszentrum Rossendorf; FZR-164 Preprint

Downloads:

Publ.-Id: 818 - Permalink


The Binary and Ternary Decay of Hot Heavy Nuclei Produced in the Reaction 14N (34 AMeV) + 197Au
Wagner, W.; Herbach, C.-M.; Ortlepp, H.-G.; Aleksandrov, A. A.; Aleksandrova, I. A.; Dietterle, L.; Doronin, V. N.; Dshemuchadse, S.; Gippner, P.; Kamanin, D. V.; Matthies, A.; Pausch, G.; Penionzhkevich, Y. E.; Renz, G.; Schilling, K.-D.; Shishkin, D. I.; Strekalovsky, O. V.; Tichtchenko, V. G.; Tsurin, I. P.; Umlauf, C.; Vakatov, D. V.; Vasko, V. M.; Wilpert, M.; Zuchko, V. E.;
  • Open Access LogoForschungszentrum Rossendorf; FZR-163 Preprint

Downloads:

Publ.-Id: 817 - Permalink


Wear mechanisms in titanium implanted silicon nitride ceramics
Brenscheidt, F.; Oswald, S.; Mücklich, A.; Wieser, E.; Möller, W.;
The wear of silicon nitride ceramics is reduced by titanium
implantation albeit the friction coefficient is slightly increased. X-ray
excited photoelectron spectroscopy indicates that silicon oxide is formed
in the wear track while possible lubricating titanium oxides are not found.
Therefore we attribute the observed wear reduction to the amorphization
of the surface as proved by transmission electron microscopy.
  • Nuclear Instruments and Methods in Physics Research B 129 (1997) 483-486

Publ.-Id: 815 - Permalink


In-situ Investigation of Ion Driff Processes in Glass ...
Schmidt, B.;
  • Lecture (Conference)
    EUROSENSORS XI, Warshaw, 21.-24.9.1997

Publ.-Id: 814 - Permalink


Two-phonon J=1 states in even-mass Te isotopes with A=122-130* Account No.: 0076898
Schwengner, R.; Winter, G.; Schauer, W.; Grinberg, M.; Becker, F.; von Brentano, P.; Eberth, J.; Enders, J.; von Egidy, T.; Herzberg, R.-D.; Huxel, N.; Käubler, L.; von Neumann-Cosel, P.; Nicolay, N.; Ott, J.; Pietralla, N.; Prade, H.; Raman, S.; Reif, J.; Richter, A.; Schlegel, C.; Schnare, H.; Servene, T.; Skoda, S.; Steinhardt, T.; Stoyanov, C.; Thomas, H. G.; Wiedenhöver, I.; Zilges, A.;
Excited states of the nuclei 122, 126, 130Te were populated
via the (gamma, gamma') reaction at endpoint energies of the bremsstrahlung
between 4.5 and 5.5 MeV. Gamma rays were detected with a EUROBALL CLUSTER
detector and a single HPGe detector. In all investigated nuclei two or
three prominent dipole transitions were identified at Egammaca.
3 MeV. The corresponding low-lying J=1 states are interpreted as two-phonon
excitations. Quasiparticle-phonon-model calculations predict at about 3
MeV on 1- state arising from coupling of the first quadrupole
and the first octupole phonon, and one 1+ state arising from
the coupling of the first and the second quadrupole phonon, where the latter
has isovector character. Such an excitation mode can be considered as an
analogue of the scissors mode in vibrational nuclei. The calculated transition
strengths are compatible with experimental ones within a factor of about
1.5.
  • Nuclear Physics A 620 (1997) 277-295

Publ.-Id: 813 - Permalink


Dichtemessung mit Positronenstrahlung
Hensel, F.;
Ein berührungsloses Dichtemeßverfahren für Medien geringer Dichte wird vorgestellt, das auf der Abhängigkeit der Reichweite von Positronenstrahlung von der Dichte des Meßmediums beruht. Die Positronen werden von einem Radionuklid in einer festen Quelle erzeugt und in das zu untersuchende Volumen emittiert. Seitlich angeordnete Detektoren registrieren die bei der Annihilation der Positronen entstehenden Gammaquanten. Das Verfahren wurde in einem Dichtebereich von 15 kg/m3 bis 38 kg/m3 getestet, eine Erweiterung des Meßbereichs von 5 kg/m3 bis 300 kg/m3 ist möglich.

Einsatzfelder sind mehrphasige Strömungen mit hohem Massenstromanteil der gasförmigen Phase (Schäume und Dämpfe) sowie unter Druck stehende Gase. Der Vorteil des Verfahrens besteht in einer Kombination der hohen Dichtesensitivität der Betastrahlung mit der geringen Absorption der bei der Annihilation entstehenden Gammastrahlung in Rohr- bzw. Behälterwänden.
  • Lecture (Conference)
    ACHEMA 97: Int. Treffen für chem. Technik, Umweltschutz und Biotechnologie, 25. Ausstellungstagung, 9.-14. Juni 1997, Frankfurt/Main

Publ.-Id: 812 - Permalink


Studies of Bubble Flows by Positron Emitting Radiotracers
Hensel, F.; Prasser, H.-M.;

Positron Emission Tomography was used in a series of experiments in the field of two-phase flow systems. The main goal was to observe mixing and flow phenomena in efficient spatial and time resolution [1].

Liquid positron emitting tracers were used for monitoring the mixing of a tracer distribution in a bubbly flow. At the beginning of the experiment an aqueous solution of Sodium Fluorine (NaF), labelled with 18F is injected into the two-phase mixture at a certain local position. This tracer starts to disperse caused by turbulence. The radiation originating from the annihilation of the positrons is detected by two opposite detector arrays, a double head spherical PET-scanner [2]. From the recorded event rates, a spatial intensity distribution of the annihilation events is calculated, which corresponds to the local concentration of the tracer.

For the experiments two setups were used. The fist consists of a flat rectangular water tank. Here the bubbly flow was generated by air injection near the tank bottom and by catalytic H2O2 decomposition, respectively. In the other setup, a vertical pipe was used. The bubbles were generated along a rod centred in the pipe, using catalytic H2O2 decomposition. In another experiment, the liquid drainage in a cellular foam was monitored.

The quantity of the active nuclide was restricted to several MBq, due to radiation protection requirements. Despite of this limitation, a good imaging is possible if the evaluation of event data can be restricted to two dimensions. For that case, a simple and time sparing midplane backprojection of the annihilation events can be applied. For the tracer, 18F was used in solution.

Using this technique, time sequences of images of the tracer concentration distribution with a time resolution of 0.5s were obtained and will be presented in the paper. This time base provides an appropriate statistical accuracy for the determination of the dispersion coefficients, too, which were determined for the bubbly flow and in the foam zone of the vertical pipe.

Transport processes in bubbly flows and foams seem to be interesting topics for investigation using a PET technique. The main advantage of PET tracers is the fact that many organic substances can be labelled with positron emitting isotopes which is important for the component sensitive investigation of many industrial processes, an objective of the further work.

  • Lecture (Conference)
    Frontiers in industrial Process Tomography, Delft, April 9-12, 1997
  • Contribution to proceedings
    Proceedings of the Conference Frontiers in Industrial Process Tomography II Delft, The Nederlands, April 9 - 12, 1997, pp. 47 - 51

Publ.-Id: 811 - Permalink


Stand der Projektvorhaben BMFT 02 S 7442 2 und Ziele des Neuantrages
Nebelung, C.; Nitsche, H.; Hübener, S.; Bernhard, G.;
  • Lecture (Conference)
    5. Sitzg. Arbeitskreis "Freimessg. v. Anlageteilen u. Bauschutt aus dem Abbau kerntechn. Anlagen des Brennstoffkreislaufes" TU München, 15.3.96

Publ.-Id: 809 - Permalink


Direktmessung alpha-aktiver Nuklide
Nebelung, C.; Nitsche, H.;
  • Lecture (Conference)
    6. Sitzg. Arbeitskreis "Freimessg. v. Anlageteilen u. Bauschutt aus dem Abbau kerntechn. Anlagen des Brennstoffkreislaufes" Rossendorf, 6.11.96

Publ.-Id: 808 - Permalink


Untersuchungen der Erwärmungsprozesse in Lagertanks mit gefährdenden Flüssigkeiten bei äußerer Brandeinwirkung
Aszodi, A.; Liewers, P.; Krepper, E.; Prasser, H.-M.;
Wenn ein zylindrischer Lagertank durch ein externes Feuer von der Seite intensiver Wärmeeinwirkung ausgesetzt ist, so setzt der Massenverlust infolge von Dampffreisetzung viel eher ein, als im Fall einer Wärmezuführung vom Behälterboden. Mittels eines vereinfachten Modells konnten die Details des Erwärmungsprozesses und die Ursachen für das unterschiedliche Verhalten in Abhängigkeit von der Art und Weise der Wärmezufuhr erklärt werden. Die ZUfuhr vom Boden führt zu einer irregulären thermischen Konvektion und damit einer guten Durchmischung des Fluids, so daß die Sättigungstemperatur an allen Punkten im Behälter nahezu gleichzeitig erreicht wird. Die maximale Enthalpie im Behälter verbleibt während der gesamten Zeit nahe dem Mittelwert. Wird der Behälter von der Seite beheizt, so bildet sich eine stabile horizontale Temperaturschichtung heraus. Die Bildung von Dampf erfolgt bereits lange bevor die mittlere Temperatur den Siedepunkt erreicht hat. Passive konstruktive Maßnahmen, wie der Einbau von Prallplatten, können die Schichtung stören, das verstärkte Aufheizen an der Oberfläche vermeiden und die Freisetzung von Dampf verzögern. Eine durchgreifende Vermischung des flüssigen Inhalts konnte jedoch nicht erreicht werden. Die genaue Gestalt und die Wirkung dieser Prallplatten hängt von der konkreten Behältergeometrie ab und läßt sich weiter optimieren.
  • Technische Überwachung 38 (1997) 4, pp. 22-25

Publ.-Id: 807 - Permalink


Dynamic instabilities in electromagnetic levitation
Priede, J.; Gerbeth, G.;
  • Contribution to proceedings
    3rd Int. Conference Transfer Phenomena in Magnetohydrodynamic & Electroconducting Flows, Aussois, France, September, 22-26, 1997, Vol. 2, pp. 377 - 384

Publ.-Id: 806 - Permalink


Velocity profile optimization for the Riga dynamo experiment
Stefani, F.; Gerbeth, G.; Gailitis, A.;
  • Contribution to proceedings
    3rd Int. Conference Transfer Phenomena in Magnetohydrodynamic & Electroconducting Flows,Aussois, France, September, 22-26, 1997, Vol. 1, pp. 27 - 32

Publ.-Id: 805 - Permalink


Two- and three-dimensional instabilities of the cylinder wake in an aligned magnetic field
Mutschke, G.; Gerbeth, G.; Shatrov, V.; Tomboulides, A.;
  • Physics of Fluids, Vol. 9, No.11, 1997, pp.3114-3116

Publ.-Id: 804 - Permalink


Technetium Coordination Ability of Cysteine-containing Peptides: X-ray Absorption Spectroscopy of a 99 Tc Labelled Endothelin Derivative
Johannsen, B.; Jankowsky, R.; Noll, B.; Spies, H.; Reich, T.; Nitsche, H.; Dinkelborg, L.; Hilger, C. S.; Semmler, W.;
  • Applied Radiation and Isotopes Vol. 48, No. 8, pp. 1045-1050, 1997

Publ.-Id: 803 - Permalink


Synthesis and Molecular Structure of a Rhenium Complex derived from 6-Methyl-8 Alpha-amino-ergoline
Spies, H.; Noll, B.; Noll, S.; Findeisen, A.; Leibnitz, P.; Schulze, P. E.; Johannsen, B.;
  • Chemische Berichte, Recueil 1997, 130, 839-841

Publ.-Id: 802 - Permalink


Das sächsische Windenergiepotential und seine Wirtschaftlichkeit
Rindelhardt, U.; Hirsch, W.;
Auf der Basis der Ergebnisse eines speziellen Windmeßprogramms und unter Nutzung des Windatlasprogramms WASP wurde das sächsische Windenergiepotential zu 6000 GWh/Jahr ermittelt. Das Erwartungspotential liegt bei 1700 GWh/Jahr (entsprechend 10% der derzeitigen Elektroenergiebedarfes). Bei einem jährlichen Ertrag einer Windenergieanlage von 2000 Vollbenutzungsstunden kann diese unter den derzeitigen Rahmenbedingungen wirtschaftlich betrieben werden. Die bisher vorliegenden Betriebsergebnisse unterstreichen die Notwendigkeit qualifizierter Standortgutachten.
  • Lecture (Conference)
    Energie und Umwelt '97, Chemnitz, 19./20.3.97, Tagungsband S. 159
  • Contribution to proceedings
    Energie und Umwelt '97, Chemnitz, 19./20.3.1997, Tagungsband S. 159

Publ.-Id: 801 - Permalink


2-D and 3-D instabilities of the cylinder wake in external magnetic fields
Mutschke, G.; Gerbeth, G.; Shatrov, V.;
  • Contribution to external collection
    APS/DFD '96, Syracuse, USA, Nov. 1996
  • Bulletin of the American Physical Society 41 (1996) 9, pp. 1715

Publ.-Id: 800 - Permalink


Separation Control of the cylinder wake using surface localized electromagnetic forces
Weier, T.; Gerbeth, G.; Mutschke, G.; Lielausis, O.; Platacis, E.;
  • Contribution to external collection
    APS/DFD '96, Syracuse, USA, 25. Nov. 1996
  • Bulletin of the American Physical Society 41 (1996) 9, pp. 1750

Publ.-Id: 799 - Permalink


Hydrothermal Wave Instability of Thermocapillary-Driven Convection in a Coplanar Magnetic Field
Priede, J.; Gerbeth, G.;
  • Journal Fluid Mechanics 11 (1996) pp. 1-000

Publ.-Id: 798 - Permalink


Experiments on cylinder wake stabilization in an electrolyte solution by means of electromagnetic forces localized on the cylinder surface
Weier, T.; Gerbeth, G.; Mutschke, G.; Platacis, E.; Lielausis, O.;
Electromagnetic body forces, i.e. Lorentz forces, have been used to modify the boundary layer around a circular cylinder in cross flow. Depending on the polarity of the applied electric field different effects on the flow can be obtained. Lorentz forces directed with the mean flow are able to prevent the boundary layer from separation. Therefore flow separation as well as the von Karman vortex trail can be suppressed. When the momentum gain produced by the Lorentz forces in the boundary layer is high enough, thrust is produced, what results in a jet flow originated from the cylinders back side. If the Lorentz forces are directed opposite to the mean flow, the separation points are shifted towards the front stagnation point, the recirculation region broadens and the von Karman vortex trail is modified. The described technique gives a variety of opportunities to control the flow around the cylinder and the flow structure of the cylinder wake. Results from flow visualizations and numerical calculations are presented.
  • Lecture (Conference)
    Flow Control - Workshop, Cargese, July 1996
  • Experimental Thermal and Fluid Science, Vol.16, 1998, pp.84-91, Elsevier Science

Publ.-Id: 797 - Permalink


On some instabilities of electromagnetically levitated spherical bodies
Priede, J.; Galindo, V.; Gerbeth, G.;
  • Contribution to proceedings
    Proceedings of the Int. Congress "Electromagnetic Processing of Materials", Paris, May 27 - 29, 1997, Vol. 2, pp. 419 - 424

Publ.-Id: 795 - Permalink


Pages: [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67] [68] [69] [70] [71] [72] [73] [74] [75] [76] [77] [78] [79] [80] [81] [82] [83] [84] [85] [86] [87] [88] [89] [90] [91] [92] [93] [94] [95] [96] [97] [98] [99] [100] [101] [102] [103] [104] [105] [106] [107] [108] [109] [110] [111] [112] [113] [114] [115] [116] [117] [118] [119] [120] [121] [122] [123] [124] [125] [126] [127] [128] [129] [130] [131] [132] [133] [134] [135] [136] [137] [138] [139] [140] [141] [142] [143] [144] [145] [146] [147] [148] [149] [150] [151] [152] [153] [154] [155] [156] [157] [158] [159] [160] [161] [162] [163] [164] [165] [166] [167] [168] [169] [170] [171] [172] [173] [174] [175] [176] [177] [178] [179] [180] [181] [182] [183] [184] [185] [186] [187] [188] [189] [190] [191] [192] [193] [194] [195] [196] [197] [198] [199] [200] [201] [202] [203] [204] [205] [206] [207] [208] [209] [210] [211] [212] [213] [214] [215] [216] [217] [218] [219] [220] [221] [222] [223] [224] [225] [226] [227] [228] [229] [230] [231] [232] [233] [234] [235] [236] [237] [238] [239] [240] [241] [242] [243] [244] [245] [246] [247] [248] [249] [250] [251] [252] [253] [254] [255] [256] [257] [258] [259] [260] [261] [262] [263] [264] [265] [266]