Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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

31738 Publications
Synthesis and Characterization of Bis(tetrabutylammonium)bis(isotrithionedithiolato-S,S')-nitrido technetate(V), (Bu4N)2[TcN(dmit)2]
Dilworth, J. R.; Hübener, R.; Abram, U.;
  • Zeitschrift für anorganische und allgemeine Chemie 623, 880 (1997)

Publ.-Id: 2652 - Permalink


X-Ray Absorption Spectroscopic and Mössbauer Studies of Redox and Cation-Ordering Processes in Manganese Ferrite
Bonsdorf, G.; Denecke, M. A.; Schäfer, K.; Christen, S.; Langbein, H.; Gunßer, W.;
  • Contribution to external collection
    HASYLAB-Annual Report 1996 I, 834 (1997)

Publ.-Id: 2651 - Permalink


Leckagen überwachen - Akustische Lecküberwachung mit neuronalen Netzen an Druckanlagen komplizierter Topologie
Hessel, G.; Schmitt, W.; van der Vorst, K.; Weiß, F.-P.;
Eine Methode zur Ortung von Lecks und zur Abschätzung ihrer Leckraten ist für Druckanlagen mit komplizierter dreidimensionaler Topologie entwickelt worden. Sie basiert auf der Merkmalsextraktion aus dem leckinduzierten Körper- oder Luftschall und benutzt neuronale Netze zur Mustererkennung. Die zum Anlernen der neuronalen Netze notwendigen Schallmuster können mit Hilfe von simulierten Lecks an der Originalstruktur erzeugt werden. Die Methode ist auch dann einsatzfähig, wenn die Leckortung auf der Basis von Laufzeit- oder Dämpfungsdifferenzen versagt. Sie wurde prototypisch für einen WWER-Druckwasserreaktor entwickelt und getestet. Als Merkmale zur Charakterisierung des Leckortes wurden Kohärenzwerte zwischen hochfrequenten Mikrofonsignalen oder die Effektivwerte der Schallemissionssensorsignale genutzt. Zur Leckratenabschätzung wurden die Merkmale ausschließlich aus den Effektivwerten dieser Schallemissionssignale gebildet. Durch die Anwendung neuronaler Netze kann die Methode ohne Schwierigkeiten an Druckanlagen unterschiedlicher Topologie angepaßt werden.
  • Book (Authorship)
    Technische Überwachung TÜ Bd. 37 (1996) Nr. 4, S. 17-22

Publ.-Id: 2649 - Permalink


Früherkennung sicherheitsrelevanter Betriebszustände in Chemieanlagen mit neuronalen Netzen
Neumann, J.; Deerberg, G.; Schlüter, S.; Schmitt, W.; Hessel, G.;
Es wird eine Methodik beschrieben, die die Früherkennung von sicherheitsrelevanten Betriebszuständen ermöglicht. Die Ergebnisse werden am Beispiel der diskontinuierlichen und kontinuierlichen Veresterung diskutiert. Bei den Arbeiten stand die frühzeitige störungsabhängige Diagnose von unerwünschten Betriebszuständen innerhalb der gesamten Anlage im Vordergrund. Die Leistungsfähigkeit neuronaler Netze für die Identifizierung bestimmungsgemäßer und nichtbestimmungsgemäßer Betriebszustände wird sowohl mit Simulationsdaten als auch mit Meßdaten der chemischen Versuchsanlage nachgewiesen.
  • Lecture (Conference)
    Tagungsband der DECHEMA-Jahrestagungen, Fachtreffen Managementsysteme, 26.-28.5.1998, Wiesbaden, S. 149
  • Contribution to proceedings
    Tagungsband der DECHEMA-Jahrestagungen, Fachtreffen Managementsysteme, 26.-28.5.1998, Wiesbaden, S. 149

Publ.-Id: 2648 - Permalink


Früherkennung gefährlicher Betriebszustände in Chemieanlagen mit neuronalen Netzen
Schlüter, S.; Neumann, J.; Steiff, A.; Schmitt, W.; Hessel, G.; van der Vorst, K.; Weiß, F.-P.;
The suitability of pattern recognition for safety diagnosis of chemical plants will be discussed. Therefore, experiments in a miniplant and with a process simulator are carried out. The process characteristics are treated with different recognition methods and classified with the aid of expert know how. Afterwards, the trained system can be used for process diagnosis. The capability of neural networks for this problem could be shown.
  • at - Automatisierungstechnik 46 (1998) 2, S. 104-110

Publ.-Id: 2647 - Permalink


The development of a superconducting rf gun: Status of the drossel collaboration
Janssen, D.; vom Stein, P.; Bushuev, A.; Karliner, M.; Konstantinov, S.; Kruchkov, S.; Petrov, V.; Sedlyarov, I.; Tribendis, A.; Volkov, V.;
In the beginning of 1996 the Drossel collaboration was established between the FZR and the BINP Novosibirsk for the development of a new electron injector. The injector combines the principle of a photocathode rf gun using a superconducting (sc) accelerating cavities. The objective of this development is a sc rf gun, which delivers a bunched electron beam in continuos wave mode. The beam parameters should fulfill the requirements of ELBE, a superconducting accelerator currently under construction at the Forschungszentrum Rossendorf. This accelerator is the base for an infrared FEL user facility and nuclear physics and radiation physics experiments.
Keywords: ELBE project, superconducting accelerating cavities, photocathode rf gun, infrared FEL, continous wave mode
  • Contribution to proceedings
    Proceedings of the Particle Accelerator Conference (1997) 2838-2839

Publ.-Id: 2646 - Permalink


Beam dynamics in RF-gun cavity with a modified first cell
Volkov, V.; Karliner, M.; Petrov, V.; Sedlyarov, I.; Tribendis, A.; Janssen, D.; vom Stein, P.;
The result of beam dynamics simulation with bunch charges up to a few tens pC in superconducting linaer accelerator for ELBE project [1] is presented. The accelerator consists of 3+1/2 TESLA cells RF-Gun and two 9-cell TESLA cavities. It is shown, that the change of a flat back wall of the half cell with cathode in its center by a conical back wall results in reduction of transversal bunch sizes and also in reduction of emittance at the accelerator exit by a factor of 20.
Keywords: superconducting linear accellerator, RF gun, TESLA cavities, ELBE project, conical back walll
  • Contribution to proceedings
    Proceedings of the Particle Accelorator Conference (1997) 2796-2798

Publ.-Id: 2645 - Permalink


Technetium and Neptunium Speciation in Cement Waste Forms
Allen, P. G.; Bucher, J. J.; Clark, S. B.; Denecke, M. A.; Edelstein, N. M.; Langton, C. A.; Nitsche, H.; Reich, T.; Shuh, D. K.; Siemering, G. S.;
  • Contribution to external collection
    Stanford Synchrotron Radiation Laboratory 1996 Activity Report, p. A-276 (1997)

Publ.-Id: 2644 - Permalink


XAFS of Neptunium Incorporated in Mammals
Allen, P. G.; Bucher, J. J.; Denecke, M. A.; Durbin, P.; Edelstein, N. M.; Kullgren, B.; Reich, T.; Shuh, D. K.;
  • Contribution to external collection
    Stanford Synchrotron Radiation Laboratory 1996 Activity Report, p. A-232 (1997)

Publ.-Id: 2643 - Permalink


Influence of Humic Acids on the Migration Behavior of Radioactive and Non-Radioactive Substances Under Conditions Close to Nature -Synthesis, Radiometric Determination of Functional Groups, Complexation-
Pompe, S.; Bubner, M.; Schmeide, K.; Heise, K.-H.; Bernhard, G.; Nitsche, H.;
The interaction behavior of humic acids with uranium(VI) and the influence of humic substances on the migration behavior of uranium was investigated. A main focus of this work was the synthesis of four different humic acid model substances and their characterization and comparison to the natural humic acid from Aldrich. A radiometric method for the determination of humic acid functional groups was applied in addition to conventional methods for the determination of the functionality of humic acids. The humic acid model substances show functional and structural properties comparable to natural humic acids. Modified humic acids with blocked phenolic OH were synthesized to determine the influence of phenolic OH groups on the complexation behavior of humic acids. A synthesis method for 14C-labeled humic acids with high specific activity was developed.
The complexation behavior of synthetic and natural humic acids with uranium(VI) was investigated by X-ray absorption spectroscopy, laser-induced fluorescence spectroscopy and FTIR spectroscopy. The synthetic model substances show an interaction behavior with uranium(VI) that is comparable to natural humic acids. This points to the fact that the synthetic humic acids simulate the functionality of their natural analogues very well. For the first time the influence of phenolic OH groups on the complexation behavior of humic acids was investigated by applying a modified humic acid with blocked phenolic OH groups. The formation of a uranyl hydroxy humate complex was identified by laserspectroscopic investigations of the complexation of Aldrich humic acid with uranium(VI)at pH 7.
The migration behavior of uranium in a sandy aquifer system rich in humic substances was investigated in column experiments. A part of uranium migrates non-retarded through the sediment, bound to humic colloids. The uranium migration behavior is strongly influenced by the kinetically controlled interaction processes of uranium with the humic colloids.
The influence of humic acids on the sorption of uranium(VI) onto phyllite was investigated in batch experiments using two different humic acids. The uranium(VI) sorption onto the rock phyllite is influenced by the pH-dependent sorption behavior of the humic acids.

Keywords: Humic substances, humic acids, model substances, humic acid synthesis, characterization, modification, radiometric analyses, 14C-labeling, complexation, uranium, migration, sorption, repository
  • Other report
    Final Report, BMBF Project No.: 02 E 88150, August 1999
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-290

Downloads:

Publ.-Id: 2642 - Permalink


Studies of Actinides by X-ray Absorption Spectroscopy
Allen, P. G.; Booth, C. H.; Bucher, J. J.; Denecke, M. A.; Edelstein, N. M.; Nitsche, H.; Reich, T.; Shuh, D. K.; Marasinghe, G. K.; Karabulut, M.; Ray, C. S.; Day, D. E.; Shumsky, M. G.;
  • Contribution to external collection
    Stanford Synchrotron Radiation Laboratory 1996 Activity Report, p. A-206 (1997)

Publ.-Id: 2641 - Permalink


Technetium Speciation in Cement Waste Forms Determined by X-ray Absorption Fine Structure Spectroscopy
Allen, P. G.; Siemering, G. S.; Shuh, D. K.; Bucher, J. J.; Edelstein, N. M.; Langton, C. A.; Clark, S. B.; Reich, T.; Denecke, M. A.;
  • Radiochimica Acta 76, 77 (1997)

Publ.-Id: 2640 - Permalink


Chemical Speciation Studies of Radionuclides by XAFS
Allen, P. G.; Shuh, D. K.; Bucher, J. J.; Edelstein, N. M.; Reich, T.; Denecke, M. A.; Nitsche, H.;
  • J. Phys. IV France 7, C2-789 (1997)

Publ.-Id: 2639 - Permalink


Investigation of Aquo and Chloro Complexes of UO22+, NpO2+, Np4+, and Pu3+ by X-ray Absorption Fine Structure Spectroscopy
Allen, P. G.; Bucher, J. J.; Shuh, D. K.; Edelstein, N. M.; Reich, T.;
  • Inorganic Chemistry 36, 4676 (1997)

Publ.-Id: 2638 - Permalink


Synthesis and characterization of indium(III) complexes with tri- and pentadentate thiosemicarbazones. Crystal and molecular structure of [InCl2(HDAPTSC)] _ 2 DMSO, {O[In(HDAPTSC)(OH)]2} _ 5 MeOH, [InCl2-(APTSC)(MeOH)], [In(APTSC)2]PF6 and (H2APTSC)][InCl(APTSC)(mnt)] _ 0.5 H2O (H2DAPTSC = 2,6-diacetylpyridine-bis(thiosemicarbazone), HAPTSC = 2-acetylpyridine-thiosemicarbazone, mnt2- = 1,2-dicyanoethene-1,2-dithiolate)
Abram, S.; Maichle-Mößmer, C.; Abram, U.;
  • Polyhedron 17 (1) 131 (1998)

Publ.-Id: 2637 - Permalink


2-[1-(Thiosemicarbazono)ethyl]pyridinium Chloride
Abram, S.; Abram, U.;
  • Acta Cryst. C53, 360 (1997)

Publ.-Id: 2636 - Permalink


Mixed-Ligand Complexes of Indium (III). Reactions of [InCl3(L1)(MeOH)] with bidentate Ligands. Synthesis, Characterization and Crystal Structures of [In(L1)Cl(ox)(OH2)] 2 H2O, [In(L1)Cl(mnt)] MeOH and [In(pythio)3] (L1 = Pyridine-2,6-bis(acetyloxime), ox2- = oxalate, mnt2- = l,2-dicyano ethene-1,2-dithiolate, pythio = pyridine-2-thiolate)
Abram, S.; Maichle-Mößmer, C.; Abram, U.;
  • Polyhedron 16, 2291 (1997)

Publ.-Id: 2635 - Permalink


Indium(III) Complexes with Tridentate Nitrogen Donor Ligands. Synthesis, Characterization and Crystal Structures of Complexes with 2,6-Bis(acetyloxime)pyridine and 2,6-Bis(1-phenylimino ethyl)pyridine
Abram, S.; Maichle-Mößmer, C.; Abram, U.;
  • Polyhedron 16, 2183 (1997)

Publ.-Id: 2633 - Permalink


Structure of Chlorobis(dimethylphenylphosphine)bis(imidotetraphenyldithiophosphinatoS,S') nitridorhenium(V)
Abram, U.; Schulz-Lang, E.; Dilworth, J. R.;
  • Acta Cryst. C53, 289 (1997)

Publ.-Id: 2632 - Permalink


Technetium(V) and Rhenium(V) Nitrido Complexes with Tetraphenylimidodithiodiphosphinate, [(Ph2PS)2N]-
Abram, U.; Schulz-Lang, E.; Abram, S.; Wegmann, J.; Dilworth, J. R.; Kirmse, R.; Woolins, J. D.;
  • J. Chem. Soc. Dalton Trans. 623 (1997)

Publ.-Id: 2631 - Permalink


Messung der Phasenverteilung bei Druckstoßversuchen
Prasser, H.-M.; Raschke, E.; Schlehlein, S.;
Zur Erfassung der Massenverteilung in Zweiphasenströmungen wurde vom Forschungszentrum Rossendorf ein Sensor entwickelt, der ein Querschnittsbild über dem Fluß in der Rohrleitung wiedergibt. Es beruht auf einer in die Rohrleitung eingebauten Gitteranordnung. Das Meßsystem ermittelt zeitlich nacheinander die Leitfähigkeit an den Gitterkreuzungspunkten und speichert diese Meßwerte als ein Bild auf einem angeschlossenen Rechner ab. Die Bildwiederholungsfrequenz beträgt 1024 Hz, das Ergebnis kann als digitaler Film vom Rechner wiedergegeben werden. Diese Untersuchungsmöglichkeit kann in der Verfahrenstechnik mehrfach Interesse finden, wenn es um Experimente zur Auslegung oder Überprüfung von Wärmetauschern, Blasensäulenreaktoren, Dampfmischern u. a. geht. Zum Zweck einer Probemessung wurde dieser Gittersensor an zwei verschiedenen Stellen in eine Druckstoßversuchsanlage (DN 80, PN 63, 21 m lang) zwischen zwei Flansche eingebaut. Es wurde die Form der auftreffenden Strömungsprofils beim Auftreten eines Kondensationsschlages ermittelt. Als Medium diente 30 %iges Methanol. Für das Experiment wurde die Rohrleitung befüllt. Anschließend wurde durch Öffnen einer im unteren Teil der Anlage angeordneten Absperrarmatur ein Teil der Flüssigkeit abgelassen. Durch die Schwerkraft bildet sich im oberen Teil der Rohrleitung eine Dampfblase. Der Druckstoß wird ausgelöst, indem eine Absperrarmatur geöffnet wird. Durch den niedrigen Druck, der in der Dampfblase herrscht, wird Flüssigkeit aus einem Speisebehälter stark beschleunigt und prallt schließlich auf den im senkrechten Abschnitt der Rohrleitung verbliebenen Flüssigkeitsspiegel. Dabei treten kurzzeitige Druckstöße in Höhe von 80 bar auf. Die Struktur des Schwalls wird im Detail durch den Sensor wiedergegeben.
  • Poster
    4. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit, VDI, Preprints, Postervortrag P5, 5./6. November 1998, Köthen
  • Lecture (Conference)
    4. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit, VDI, Preprints, Postervortrag P5, 5./6. November 1998, Köthen
  • Contribution to proceedings
    4. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit, VDI, Preprints, Postervortrag P5, 5./6. November 1998, Köthen

Publ.-Id: 2630 - Permalink


Erfassung schneller Verdampfungs- und Kondensationsprozesse mit dem Gittersensor, Seminar Druckstöße
Prasser, H.-M.;
Speziell für die Druckstoßuntersuchungen an der Druckstoß-Versuchsanlage von Fraunhofer UMSICHT in Oberhausen wurde vom Forschungszentrum Rossendorf ein Gittersensor zur schnellen Visualisierung der Verdampfungs- und Kondensationsvorgänge hinter einer schnellschließenden Armatur entwickelt. Er basiert auf der Messung der momentanen örtlichen elektrischen Leitfähigkeit des Zweiphasengemischs. Die Zeitauflösung des Geräts beträgt 1024 Messungen in der Sekunde. Der Sensor besteht aus zwei dicht hintereinander angeordneten Elektrodengittern mit jeweils 16 Elektroden. Die Messung erfolgt an den Kreuzungspunkten der Elektroden, d.h. an 16 x 16 Meßpunkten, die gleichmäßig über die Querschnittsfläche des Strömungskanals verteilt sind. Der Sensor ist in zwei Ausführungen verfügbar: (1) als Drahtgittersensor für Laboranwendungen und (2) als "schwerer" Sensor mit verstärkten Elektrodenstäbchen für höhere strömungsmechanische Belastungen. Letzterer wurde bei einer Vielzahl von Experimenten in Oberhausen erfolgreich eingesetzt. Eines der Ergebnisse ist ein neuartiges Verfahren zur Verhinderung des Kaviattionsschlages hinter einer Schnellschlußklappe. Durch Anordnung einer Hilfsarmatur hinter der eigentlichen Absperrarmatur ist eine Schnellabsperrung der Rohrleitung ohne Kavitationsschläge möglich. Der Einsatz von Rückschlagklappen stellt hierbei eine kostengünstige Variante dar. Um sekundäre Kavitationsschläge zu vermeiden, muß der Abstand zwischen Absperr- und Hilfsarmatur ausreichend bemessen sein. Die Hilfsarmatur muß einen möglichst geringen Druckverlust aufweisen. Durch geeignete technische oder organisatorische Maßnahmen muß sichergestellt werden, daß die Absperrarmatur nicht oder nur hinreichend langsam geöffnet werden kann, solange zwischen Absperr- und Hilfsarmatur eine Kavitationsblase eingeschlossen ist.
  • Lecture (Conference)
    Dampfschläge und Pulsationen in Rohrleitungen, Organisator: Haus der Technik e.V., Oberhausen, 20.-21.10.1998

Publ.-Id: 2629 - Permalink


Messung von Blasengrössenverteilungen mit Gittersensoren
Prasser, H.-M.;
Auf dem Workshop Zweiphasenmeßtechnik 1997 wurde ein im Forschungszentrum Rossendorf entwickelter Gittersensor vorgestellt, der die Ermittlung von momentanen Gasgehaltsverteilungen in einem Rohrleitungsquerschnitt mit einer örtlichen Auflösung von ca. 3 mm bei einer Meßfolge von 1024 Hz erlaubt. Bei moderaten Strömungsgeschwindigkeiten (bis zu einigen m/s) werden dadurch die einzelnen Gasblasen in mehreren, zeitlich aufeinanderfolgenden Verteilungen abgebildet. Die Meßdaten können demzufolge für die Ermittlung von Blasengrößenverteilungen genutzt werden. Sie werden hierzu als dreidimensionale Gasgehaltsverteilung interpretiert, wobei eine virtuelle vertikale Achse aus der mittleren Strömungsge-schwindigkeit der Gasphase und der Meßfrequenz des Gittersensors näherungsweise definiert wird. An den Gitterpunkten dieser dreidimensionalen Verteilung liegt Gas, Flüssigkeit oder ein Gasgehalt zwischen 0 und 100 % vor. Letzterer ist als teilweise Belegung des Meßvolumens mit der Gasphase zu betrachten. Eine Blase ist ein zusammenhängendes, von der Gasphase eingenommenes Raumgebiet. Das Blasenvolumen kann daher näherungsweise ermittelt werden, indem die lokalen Gasanteile summiert werden, die an den zur Blase gehörenden Gitterpunkten vorliegen. Hierzu wurde ein spezieller rekursiver Algorithmus entwickelt, der analog zu den aus der Bildverarbeitung bekannten Füllalgorithmen, alle Gitterpunkte abarbeitet, die zu einem zusammenhängenden Gebiet gehören. Als Begrenzung der Gasgebiete muß ein unterer Schwellwert für den Gasgehalt eingeführt werden. Im Beitrag werden Ergebnisse vorgestellt, die in einer vertikalen, mit einem Wasser-Luft-Gemisch durchströmten Rohrleitung erhalten wurden. Die Leerrohrgeschwindigkeiten wurden in einem weiten Bereich variiert, so daß der Übergang von der Blasenströmung über die Pfropfenströmung bis zur Ringströmung erfaßt wurde. Die Ergebnisse zeigen den Übergang von der durch die Gaseinperlung erzeugten monomodalen Blasengrößenverteilung zur bimodalen, für eine Pfropfenströmung typischen Verteilung entlang des Strömungswegs. Dabei treten sowohl Koaleszenz- als auch Fragmentationsereignisse auf. Weiterhin werden gemessene Gasgehaltsprofile vorgestellt.
  • Lecture (Conference)
    Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen", Rossendorf, 24.-25. Sept. 1998, Forschungszentrum Rossendorf; FZR-241, S. 157-164
  • Contribution to proceedings
    Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen", Rossendorf, 24.-25. Sept. 1998, Forschungszentrum Rossendorf; FZR-241, S. 157-164

Publ.-Id: 2628 - Permalink


Visualisierung der Zweiphasenströmung in einer vertikalen Rohrleitung
Prasser, H.-M.; Böttger, A.; Zschau, J.;
  • Lecture (Conference)
    DECHEMA-Jahrestagungen '98, 26.-28. Mai 1998, Wiesbaden, Fachtreffen Sicherheitstechnik, Kurzfassungen Band 2 S. 162
  • Poster
    DECHEMA-Jahrestagungen '98, 26.-28. Mai 1998, Wiesbaden, Fachtreffen Sicherheitstechnik, Poster C.08, Kurzfassungen Band 2 S. 162.
  • Contribution to proceedings
    DECHEMA-Jahrestagungen '98, 26.-28. Mai 1998, Wiesbaden, Fachtreffen Sicherheitstechnik, Kurzfassungen Band 2 S. 162

Publ.-Id: 2627 - Permalink


Spreading Resistance Messungen an Siliziumkarbid (6H-SiC)
Gebel, T.;
  • Other report
    TU Dresden, 29.9.1998

Publ.-Id: 2626 - Permalink


Aufwallen und Austragen von zweiphasigen Gemischen
Prasser, H.-M.; Steinkamp, H.; Rohde, U.;
  • Lecture (Conference)
    DECHEMA-Jahrestagung 1995, 30.05.-01.06.1995, Wiesbaden

Publ.-Id: 2625 - Permalink


Temperature and energy spread investigations of alloy LMIS
Bischoff, L.; Teichert, J.; Hausmann, S.; Ganetsos, T.; Mair, G. L. R.;
Emitters wetted with Ga, Au73Ge27, Au77Ge14Si9 and Co36Nd64 alloys were investigated with regard to the influence of the source temperature on the current-voltage characteristics and the energy spread of the different emitted ions. The latter was measured using a system that includes an ExB mass filter and a retarding field energy analyser. The energy spread significantly affects the available FIB spot size and depends also on the emission current, the charge state, and the mass of the ions or clusters. The influence of the source parameters, temperature and energy spread, on the beam performance in terms of spot size measurements is demonstrated with a 70 keV Ge2+ beam using the FIB system IMSA - 100.
Keywords: alloy liquid metal ion source, focused ion beam, spot size, energy spread, temperature
  • Lecture (Conference)
    International Conference on Micro - and Nano - Engineering, MNE`99 September 21 - 23, 1999, Rome, Italy Microelectronic Engineering 53 (2000) 613 - 616

Publ.-Id: 2624 - Permalink


Tribological investigations of surface treated Ti6Al4V
Rück, D. M.; Schminke, A.; Schmidt, H.; Soltani-Farshi, M.; Baumann, H.; Fink, U.; Richter, E.;
  • Other report
    GSI-98-29

Publ.-Id: 2623 - Permalink


Abschlußbericht 'PAS-Untersuchungen an 2024-Blechen' (Stand: 18.12.1998)
Brauer, G.; Nicht, E.-M.;
  • Other report
    Industrie-Projekt Nr. 3448109

Publ.-Id: 2622 - Permalink


Materialforschung mittels Positronen-Annihilationsspektroskopie
Brauer, G.;
  • Other report
    SMWK: 4-7533-70-FZR/705, Zwischenberichte 22.01.1998, 14.07.1998

Publ.-Id: 2621 - Permalink


Implantationsdotierung von Diamant
von Borany, J.; Fontaine, F.;
  • Other report
    Zwischenbericht zum Verbundprojekt: Sensorcluster für extreme Umgebungsbedingungen, BMBF - FKZ: 16 SV 548/2, February 1998

Publ.-Id: 2620 - Permalink


Mikrofluidhandlingsystem für die chemische Analytik und Biotechnologie
von Borany, J.; Gehring, T.;
  • Other report
    Abschlußbericht zum SMWA-Projekt, FKZ: 42-4333.15, June 1998

Publ.-Id: 2618 - Permalink


Plasma-Immersions-Implantation – ein modernes Verfahren zur Modifizierung von Werkstückoberflächen
Günzel, R.; Richter, E.;
  • Lecture (others)
    Werkstoffforum der Hannover Messe, April 20 – 22, 1998

Publ.-Id: 2617 - Permalink


Ion beam synthesis of Ge-rich SiO2-layers for photo-and electroluminescence
Skorupa, W.;
  • Lecture (others)
    Fed. Univ. of Rio Grande dol Sul, Porto Alegre, Brasilien, Nov. 13, 1998

Publ.-Id: 2616 - Permalink


The mechanism of diffusional transport during ion nitriding of aluminium
Telbizova, T.; Parascandola, S.; Kreissig, U.; Günzel, R.; Möller, W.;
The mechanism of thermal transport during low-energy ion nitriding of aluminium has been investigated using marker and isotope sequence techniques in connection whit ion beam analysis. For an ion energy of 1 keV and a temperature of 400°C, it is shown that stoichiometric nitride grows at the surface with aluminium being supplied by diffusion from the underlying bulk.
Keywords: Al, ion nitriding, thermal transport, diffusion
  • Applied Physics Letters Vol 76 (2000) No. 11, 1404-1406

Publ.-Id: 2615 - Permalink


Single event and soft error effects in silicon based device configurations
Skorupa, W.;
  • Lecture (others)
    AMD (Advanced Micro Devices) Saxony GmbH, Dresden, Oct. 15, 1998

Publ.-Id: 2614 - Permalink


Photo- and electroluminescence studies at ion beam synthesized Ge-rich SiO2-layers
Skorupa, W.;
  • Lecture (others)
    Advanced Lectureship Program, Dept. of Appl. Phys., Univ. of Barcelona, Spain, May 12, 1998

Publ.-Id: 2613 - Permalink


Advanced ion beam processing of semiconductor materials
Skorupa, W.;
  • Lecture (others)
    Advanced Lectureship Program, Dept. of Appl. Phys., Univ. of Barcelona, Spain, May 11, 1998

Publ.-Id: 2612 - Permalink


Ion beam processing of single crystalline SiC
Skorupa, W.;
  • Lecture (others)
    UK-User Meeting of the Ion Beam Laboratory at the School of Mathematics, Physics and Engineering, University of Surrey, UK, April 1-3, 1998
  • Lecture (others)
    Institut für Elektrotechnik, RWTH Aachen, Oct.19, 1998
  • Lecture (others)
    Fed. Univ. of Rio Grande dol Sul, Porto Alegre, Brasilien, Nov.5, 1998

Publ.-Id: 2611 - Permalink


Nitrierung von Leichtmetallen durch Ionenimplantation
Richter, E.; Möller, W.;
  • Lecture (others)
    ATW-Tagung, Freiberg, April 15-16, 1998

Publ.-Id: 2610 - Permalink


Photoluminescence and electroluminescence investigations at Ge-rich SiO2 layers
Rebohle, L.;
  • Lecture (others)
    Sommerschule "Enrico Fermi", Varenna, Italy, 21-31 July 1998

Publ.-Id: 2609 - Permalink


Computersimulation der Ionenimplantation in der Si-Technologie: Wechselspiel zwischen Kanalisierung und Defektbildung
Posselt, M.;
  • Lecture (others)
    Physikalisches Institut der Universität Münster, July, 3, 1998

Publ.-Id: 2608 - Permalink


Zweiphasenströmung und Schaumbildung in Membranelektrolysezellen
Schneider, C.;
Merkmale der Zweiphasenströmung in elektrochemischen Membranzellen mit gasenden Elektroden sind eine kontinuierliche Zunahme des Gasvolumenstroms über die Zellenhöhe, die Bildung relativ kleiner Gasbläschen an der Elektrode, sowie die hohe Konzentrationen gelöster anorganischer Elektrolyte, die zu einer Behinderung der Koaleszenz führen. Aufgrund dieser Besonderheiten geht die Blasenströmung bei entsprechend hoher Gasproduktion in Richtung Zellenkopf in eine Schaumzone über. Die Nachbildung einer Elektrodenreaktion mit Gasentwicklung wird durch die katalytische Zersetzung von Wasserstoffperoxid an Platin realisiert. Anhand von axialen Gasgehaltsverteilungen werden die Strömungsverhältnisse in zwei Versuchsanordnung beschrieben. Die zylindrische Versuchszelle mit einem Innendurchmesser von 52 mm und einer Höhe von 1,2 m besitzt als Katalysator ein zentral angeordnetes, platinbeschichtetes Titanrohr von 16 mm Außendurchmesser. Die Versuchszelle mit rechteckigem Querschnitt wurde zur weiteren Annäherung an die originalen Elektrolysezellen aufgebaut. Die beide Anordnungen stehen bei gleicher Arbeitshöhe in einem Volumenverhältnis von 1:3, wodurch Aussagen zum Scale-up möglich werden. Die rechteckige Versuchszelle verfügt über einen gerippten Katalysator, der die originale Gestalt der Elektrode annähernd wiedergibt. Durch die Konzentration der Wasserstoffperoxids im Feedstrom und durch die Prozeßtemperatur wird der gewünschte Gasvolumenstrom eingestellt. Der volumetrische Gasgehalt und das axiale Gasgehaltsprofil werden mittels über die Zellenhöhe angeordneten Differenzdruckaufnehmern gemessen. Bei kleinen Gasbelastungen dominiert der Bereich der Kleinblasenströmung (Gasgehalte < 60%). Der volumetrische Gasgehalt steigt zunächst annähernd linear mit der Säulenhöhe an. Hiernach geht die Kurve in einen degressiven Verlauf über, der für eine heterogene Blasenströmung mit konstanter Schwarmaufstiegsgeschwindigkeit charakteristisch ist. Innerhalb der Schaumzone, bei Gasgehalten von ca. 60% bis ca. 70% bildet sich ein Plateau im axialem Gasgehaltsprofil heraus. Hier wird der Mehreintrag an Gas durch die Zunahme der Blasenauftriebsgeschwindigkeit infolge von Koaleszenzereignissen ausgeglichen. Im Zellenkopf ist ein weiterer Anstieg des Gasgehalts auf Werte bis zu 84 % zu verzeichnen. Bei gleicher Zellenleistung werden in der flachen Zelle kleinere Gasgehalte erhalten als in der zylindrischen Anordnung. Dieses Verhalten wird auf die durch die Jalousieform des Katalysators bedingte bimodale Blasengrößenverteilung der Primärblasen zurückgeführt. Mittels Gammadensitometrie wurde in der flachen Zelle das Gasgehaltsprofil senkrecht zum Katalysator gemessen. Entgegen dem visuellen Eindruck bleibt der Gasgehalt entlang der Zellentiefe konstant. Der in unmittelbarer Nähe des Katalysators erwartete Gasgehaltsgradient konnte wegen konstruktiver Begrenzungen nicht beobachtet werden. Riser- und Downcomerzone der Zirkulationsströmung der Flüssigkeit wurden mit LDA-Messungen nachgewiesen.
  • Poster
    DECHEMA-Jahrestagungen, Wiesbaden 1998

Publ.-Id: 2606 - Permalink


Spatial distribution of defects in ion-implanted and annealed Si: the Rp/2 effect
Peeva, A.;
  • Lecture (others)
    Fed. Univ. of Rio Grande dol Sul, Porto Alegre, Brasilien, Oct.27, 1998

Publ.-Id: 2605 - Permalink


Rolle und Akzeptanz der Kernenergie in einem zukunftsfähigen Stromversorgungskonzept
Fietz, J.;
  • Lecture (Conference)
    VDI-KTG-Seminar, Dresden, 17.6.1999

Publ.-Id: 2604 - Permalink


Grundlegende Untersuchungen zum Dresdner Untergrundlabor für die Messung kleinster Radioaktivitäten (Niederniveau-Meßlabor)
Fietz, J.; Köhler, M.; Nitsche, H.;
  • Open Access LogoAbschlußbericht zum SMWK-Förderprojekt 4-7531.50-03-FZR/608, Juni 1997

Publ.-Id: 2603 - Permalink


The Rossendorf Research Site
Fietz, J.;
  • Lecture (Conference)
    LOWRAD 96, Methods and Applikations of Low-Level Radioactivity Measurements, Rossendorf / Dresden, 7 - 8 November 1996

Publ.-Id: 2601 - Permalink


LOWRAD 96, Methods and Applications of Low-Level Radioactivity Measurements
Fietz, J.; Nitsche, H.; Niese, S.; (Editors)
  • Contribution to proceedings
    Proceedings of a Workshop, Rossendorf / Dresden, 7 - 8 November 1996
  • Open Access LogoForschungszentrum Rossendorf; FZR-170, March 1997

Downloads:

Publ.-Id: 2600 - Permalink


The scientific analysis of Böttger stoneware at the Research Center Rossendorf (Dresden, Germany)
Neelmeijer, C.;
  • Invited lecture (Conferences)
    1st Int. Workshop on the non-destructive characterisation of Böttger stoneware, J. Paul Getty Museum - Los Angeles/Cal., Nov. 1998

Publ.-Id: 2599 - Permalink


Decommissioning of old uranium ore extraction and traetment installations
Hebert, J. P.; Daroussin, J. L.; Michel, P.; Perih, C.; Lozano Martinez, F.; Lopez Romero, A.; Fietz, J.; Langer, L.; Kahn, A.; Litvin, V.; Nitsche, H.;
  • Book (Authorship)
    Contract No FI2D/CT93/0083, Final Report, EUR 16885 EN, ISBN 92-827-6823-6, ECSC-EC-EAEC, Brussels-Luxembourg 1996

Publ.-Id: 2598 - Permalink


Oberflächenmodifizierung von Hartmetallen mittels Bor-Implantation
Mrotschek, I.;
  • Lecture (others)
    Weißrussische Universität Minsk, July 28, 1998

Publ.-Id: 2597 - Permalink


Der Unfall von Tschernobyl und seine Folgen - eine Bilanz aus heutiger Sicht
Fietz, J.;
  • Lecture (Conference)
    Zentrumskollqium des FZR, Rossendorf, 27.3.1996

Publ.-Id: 2596 - Permalink


Plasma immersion and low-energy ion implantation for the nitriding of metal surfaces
Möller, W.;
  • Lecture (others)
    Charles University Prag, Dept. of Polymer Physics, Oct. 26, 1998

Publ.-Id: 2595 - Permalink


Environmentel radioactive contamination caused by the uranium extraction industry and problems of site remediation in the East European countries
Fietz, J.;
  • Lecture (Conference)
    IRPA Symposium on Radiation Protection in Neigthbouring Countries in Central Europe, Portoroz, Slovenia, Sept. 4 - 8, 1995

Publ.-Id: 2594 - Permalink


Neue Technologien der Ionenimplantation
Möller, W.;
  • Lecture (others)
    Ruhr-Universität Bochum, Fakultät für Physik, April 20, 1998

Publ.-Id: 2593 - Permalink


Forschung mit Ionenstrahlen: Grundlagen und Anwendungen
Möller, W.;
  • Lecture (others)
    MPI für Plasmaphysik, Garching, April 17, 1998
  • Lecture (others)
    FernUniversität Hagen, April 21, 1998

Publ.-Id: 2592 - Permalink


Die deutsche Beamline in Grenoble - Vom Radionuklidverhalten in der Umwelt bis zu Festkörper-untersuchungen
Matz, W.;
  • Lecture (others)
    1. BEAMline Seminar, Bundesanstalt für Materialprüfung Berlin, 12.-13. November 1998

Publ.-Id: 2591 - Permalink


Materialforschungsmeßplatz bei ROBL - erste Ergebnisse und Möglichkeiten
Matz, W.; Betzl, M.; Schell, N.; Eichhorn, F.; Prokert, F.;
  • Lecture (others)
    Programmseminar des IIM, Rossendorf, Mai 1998

Publ.-Id: 2590 - Permalink


Analytical methods of CNx film investigations in Rossendorf – results
Kolitsch, A.; Möller, W.;
  • Lecture (others)
    Kick-off Meeting of the TMR Project "New carbon based hard materials", Stockholm, Sweden, January 1998

Publ.-Id: 2589 - Permalink


Preparation of CNx films by ion beam assited deposition
Kolitsch, A.; Möller, W.;
  • Lecture (others)
    Kick-off Meeting of the TMR Project "New carbon based hard materials", Stockholm, Sweden, January, 1998

Publ.-Id: 2588 - Permalink


Implantation defects in Si at half of the projected ion range (1/2 Rp)
Kögler, R.;
  • Lecture (others)
    Fed. Univ. of Rio Grande dol Sul, Porto Alegre, Brasilien, Nov.17, 1998

Publ.-Id: 2587 - Permalink


Ionenstrahlinduzierte Rekristallisation von amorphen SiC-Schichten
Höfgen, A.;
  • Lecture (others)
    Institut für Physik, TU Chemnitz, May 11, 1998

Publ.-Id: 2586 - Permalink


Anwendungen der Rossendorfer Kernmikrosonde als Schwerionenmikroskop
Herrmann, F.; Grambole, D.;
  • Lecture (others)
    Arbeitstreffen Forschung mit nuklearen Sonden und Ionenstrahlen, Leipzig, 5. - 7. Okt. 1998

Publ.-Id: 2585 - Permalink


Ion beam synthesis of nanocrystals in SiO2: experiments, modeling and computer simulations
Heinig, K.-H.;
  • Lecture (others)
    Vanderbilt University, Nashville, TN, USA, June 29, 1998

Publ.-Id: 2584 - Permalink


Ion beam synthesis of nanocrystals - fundamentals and experiments
Heinig, K.-H.;
  • Lecture (others)
    Oak Ridge National Laboratory, Solid State Division, Oak Ridge, TN, USA, June 26, 1998

Publ.-Id: 2583 - Permalink


Nanokristalle: Ein neues Material der Opto- und Halbleiterelektronik?
Heinig, K.-H.;
  • Lecture (others)
    Physikalisches Institut der Universität Kaiserslautern, Jan. 19, 1998

Publ.-Id: 2582 - Permalink


Verschleißfester Edelstahl durch Plasmaimmersions-Ionenimplantation
Günzel, R.;
  • Lecture (others)
    Robert Bosch AG, Crailsheim, March 9, 1998

Publ.-Id: 2581 - Permalink


In-situ -Ionenstrahlanalytik während der Ionenstrahlmodifikation dünner Schichten
Grötzschel, R.;
  • Lecture (others)
    ETH Zürich, 9.6.1998

Publ.-Id: 2580 - Permalink


Hochtemperatur-Implantation von Diamant
Fontaine, F.; von Borany, J.;
  • Lecture (others)
    2. Statusseminar zum BMBF-Verbundprojekt 'Sensorcluster für extreme Umgebungsbedingungen', Fernuniversität Hagen, 2./3. Juni 1998

Publ.-Id: 2579 - Permalink


Charakterisierung leerstellenartiger Defekte in ionenimplantiertem SiC mit Positronen
Brauer, G.;
  • Lecture (others)
    FZ Rossendorf, Zentrumsseminar, 10.12.1998

Publ.-Id: 2578 - Permalink


Comparative study of ion implanted SiC by slow positron implantation and Rutherford backscattering/ channeling spectroscopies
Brauer, G.;
  • Lecture (others)
    Texas Christian University (Department of Physics), Ft. Worth/TX, 02.11.1998
  • Lecture (others)
    University of Texas at Arlington (Physics Department), Arlington/TX, 03.11.1998

Publ.-Id: 2577 - Permalink


Uranium(VI) Sorption onto Phyllite and Selected Minerals in the Presence of Humic Acid
Schmeide, K.; Pompe, S.; Bubner, M.; Heise, K. H.; Bernhard, G.; Nitsche, H.;
We studied the influence of humic acid (HA) on the uranium(VI) sorption onto the rock material phyllite and onto its main mineralogical constituents quartz, muscovite, chlorite, and albite at an ionic strength of 0.1 M in the pH range of 3.5 to 9.5 under aerobic conditions. The uranium(VI) concentration was 1·10-6 M and the HA concentration was 5 and 60 mg/L, respectively. The mass loading was 12.5 g/L. Furthermore, we studied the uranium and HA sorption on ferrihydrite (3·10-4 M Fe) and compared the results to the sorption behavior of phyllite. The study showed that the uranium sorption onto phyllite and onto its mineralogical constituents is influenced by the pH-dependent sorption behavior of the HA. Due to high HA sorption onto the solids in the acidic pH range the uranium uptake is enhanced compared to the uranium uptake in the absence of HA. A high concentration of dissolved HA in the near-neutral pH range may reduce the uranium sorption due to formation of aqueous uranyl humate complexes. Furthermore, we could show that the high uranium and HA sorption on phyllite is primarily caused by minor amounts of the secondary mineral ferrihydrite that is formed due to weathering of phyllite. Thus, the ferrihydrite predominates the contributions of the main minerals quartz, muscovite, chlorite, and albite, that are naturally present in the rock material phyllite.
Keywords: Humic acid, Uranium, Sorption, Phyllite, Muscovite, Albite, Quartz, Ferrihydrite
  • Radiochimica Acta 88, 723-728 (2000)

Publ.-Id: 2576 - Permalink


Institute of Bioinorganic and Radiopharmaceutical Chemistry; Report January 1998 - Juni 1999
Johannsen, B.; Seifert, S.;
FOREWORD
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf, FZR-270 September 1999

Downloads:

Publ.-Id: 2575 - Permalink


Nanoscale Precipitates in VVER-440-type Reactor Pressure Vessel Steels after Irradiation and Annealing
Böhmert, J.; Große, M.; Ulbricht, A.;
The microstructural evolution of reactor pressure vessel (RPV) steel effected by neutron irradiation is not yet sufficiently understood. The issue, however, is highly relevant for a safe operation of nuclear power plants (NPP).
Investigations have been performed by the methods of analytical high-resolution transmission electron microscopy (AHRTEM), the small angle neutron scattering (SANS) and the anomalous small angle X-ray scattering (ASAXS). The materials selected represent two different state-of-the-art products of VVER-type RPV steels.
One material is typical for the first VVER-440/230 generation and has a quite high content of impurities. The second material consists of surveillance specimens manu factured by Skoda Pilsen for the VVER 440/213 NPP in Paks (Hungary). The materials were irradiated to fluences of 7 to 14x1023 n/m2 (E > 1 MeV) within a high flux channel of the VVER prototype VVER-2 in Rheinsberg (Germany), or in the surveillance position of the Paks NPP, respectively. Whereas the detection of irradiation-induced precipitates by AHRTEM was not successful in every case, SANS showed an increase in the scattering intensity after irradiation, which could be interpreted as caused by a bimodal size distribution of irradiation-induced precipitates. A high first peak of the distribution appears at a radius of the precipitates of 1 to 2 nm. This peak disappears after annealing and is especially high but also thermally unstable for charges with high copper content. ASAXS measu rements prove that these precipitates are vanadium rich. There is a clear correlation between the integral of the sieze distribution within the range of the first peak of the distribution curve and the hardness. The correlation is independent of the treatment or the fluence. This shows the fine-dispersed nano-scale precipitates are the reason of the irradiation hardening.
  • Lecture (Conference)
    Third International Ural Seminar, Radiation Damages Physics of Metals and Alloys, Abstracts, 21-27 February 1999, Snezhinsk, Russia, p. 32
  • Contribution to proceedings
    Third International Ural Seminar, Radiation Damages Physics of Metals and Alloys, Abstracts, 21-27 February 1999, Snezhinsk, Russia, p. 32

Publ.-Id: 2574 - Permalink


Einfluss von Seigerungen in dickwandigen Teilen aus Druckbehälterstählen auf die Zähigkeitskennwerte
Böhmert, J.; Müller, G.; Viehrig, H.-W.;
In dickwandigen Teilen aus den Druckbehälterstählen ASTM A533 B Cl. 1, 15CrMoV2 und 15CrNiMo2 wurde die Tiefenlagenabhängigkeit der Zähigkeit mit Kerbschlagbie geversuchen und mit quasistatischen 3-Punkt-Biegeversuchen an ermüdungsangeris senen Proben in Charpy-V-Geometrie nach dem ¿master curve¿-Konzept nach Wallin bestimmt. In bestimmten Tiefenbereichen treten Anomalien im Verlauf der Tiefenlagenabhängigkeit der mit den genannten Methoden ermittelten Übergangstemperaturen auf. Eine eingehendere Analyse zeigt, dass die Streuungen in den Zähigkeitskennwerten bimodal verteilt sind. Als Ursache werden Seigerungslinien ausgewiesen, in denen vorzugsweise der Kohlenstoffgehalt angereichert ist. Als Folge dessen entsteht in diesem Bereichen ein deutlich härteres, martensitisches Gefüge.
Die Lage der Linien relativ zur Rissspitze bestimmt die Bruchzähigkeit und damit die Referenztemperatur To nach dem ¿master curve¿-Konzept. Im Charpy-Kerbschlagbie geversuche ist eine derartige eindeutige Zuordnung nicht nachzuweisen.
  • Poster
    Tagung "Gefüge und Bruch", Internationale Werkstoffprüftagung, 17.-19. März 1999, Bochum, Vortrag Nr. 19
  • Contribution to proceedings
    Tagung "Gefüge und Bruch", Internationale Werkstoffprüftagung, 17.-19. März 1999, Bochum, Vortrag Nr. 19

Publ.-Id: 2573 - Permalink


Anlagentechnik für die Plasmaimmersions-Ionenimplantation
Günzel, R.;
  • Lecture (others)
    Anwenderforum AWS, Meisdorf, December 12, 1998

Publ.-Id: 2572 - Permalink


Irradiation-induced structural changes in surveillance material of VVER 440-type weld metal
Große, M.; Denner, V.; Böhmert, J.; Mathon, M.-H.;
The irradiation-induced microstructural changes in surveillance materials of the VVER
440-type weld metal Sv-10KhMFT were investigated by small angle neutron scattering
(SANS) and anomalous small angle X-ray scattering (SAXS). Due to the high fluence
a strong effect was found in the SANS experiment. No significant effect of the irradiationis detected by SAXS. The reason of this discrepancy is the different
scattering contrast of irradiation-induced defects for neutron and X-rays. An analysis
of the small angle X-ray scattering shows that the scattering intensity is mainly caused by vanadium-containing precipitates and grain boundaries. Both types of scattering defects are hardly changed by irradiation. Neutron irradiation rather produces additional scattering defects of few nanometers in size. Assuming these defects are clusters containing copper and other foreign atoms with a composition according to results of atom probe field ion microscopy investigations, both the high SANS and the low SAXS effect can be explained.
  • Journal of Nuclear Materials 277 (2000) 280-287

Publ.-Id: 2571 - Permalink


Möglichkeiten der Röntgenuntersuchungen an Wafern in Rossendorf und an der ESRF
Eichhorn, F.; Matz, W.; Prokert, F.;
  • Lecture (others)
    WACKER Siltronic, Burghausen, 14.10.1998

Publ.-Id: 2570 - Permalink


Characterization of vacancy-type defects in ion implanted SiC by positron annihilation spectroscopy
Brauer, G.;
  • Lecture (Conference)
    University of the Witwatersrand (Schonland Research Centre for Nuclear Sciences), Johannesburg, 12.01.1998

Publ.-Id: 2569 - Permalink


Miniaturisiertes Analysesystem für die Gewässerüberwachung
von Borany, J.; Cabaleiro, S.;
  • Lecture (others)
    Abschlußseminar zum SMWA-Verbundprojekt; Dresden, 30. 06.1998
  • Other report
    Abschlußbericht zum SMWA-Verbundprojekt, FKZ: 42-4333.16, June 1998

Publ.-Id: 2568 - Permalink


Electrical and microstructural effects in highly doped 6H-SiC after Al-implantation
Wirth, H.; Panknin, D.; Perez-Rodriguez, A.; Brauer, G.; Anwand, W.; Voelskow, M.; Skorupa, W.;
  • Lecture (Conference)
    40th Electronic Materials Conference (EMC´98), Charlottesville, Virginia, USA, June 24-26, 1998

Publ.-Id: 2567 - Permalink


Neutron Spectrum Covariances and their Influence on Results of Pressure Vessel Neutron Spectrum Adjustments
Böhmer, B.; Manturov, G.;
  • Voprosy Atomnoi Nauki i Techniki, Seriya Jadernye Konstanty, 1998, Vypusk 1, p. 28-34, Ed. ZNIIatominform, Moscow

Publ.-Id: 2566 - Permalink


Spatial distribution of gettering centres in ion-implanted and annealed silicon
Kögler, R.; Eichhorn, F.; Mücklich, A.; Skorupa, W.; Danilin, A. B.;
  • Lecture (Conference)
    11th. Int. Conf. on Ion Beam Modification of Materials, Amsterdam, The Netherlands, Aug. 31 - Sept. 4, 1998

Publ.-Id: 2565 - Permalink


SANS Investigations of the Microstructure of VVER-440-Type RPV Steel after Low Temperature Irradiation at 60 grd C
Grosse, M.; Böhmert, J.; Gilles, R.;
  • Journal of Nuclear Materials 254 (1998) 143-150

Publ.-Id: 2564 - Permalink


MHD turbulence measurements in a sodium channel flow exposed to a transverse magnetic field
Eckert, S.; Gerbeth, G.; Witke, W.; Langenbrunner, H.;
The knowledge about properties of the anisotropic turbulence in liquid metal flows exposed to an external magnetic field is essential for several technological applications such as the concept of a self-cooled liquid metal blanket for thermonuclear fusion reactors or the electromagnetic brake in metallurgical processes, but also of basic interest for turbulence research. Flow arameters like pressure drop and heat transfer rate are essentially determined by the interaction between the external magnetic field and the liquid metal flow. Several experimental studies [1-3] revealed that the application of a magnetic field leads not exclusively to a suppression of the turbulent perturbations. Velocity fluctuations remain and demonstrate a distinct anisotropy of the MHD turbulence showing a tendency to become two-dimensional. The properties of the local mass transfer are strongly
governed by the anisotropic character of the flow [4,5]. In this context a number of questions arises regarding the origin, the decay time or the size of the turbulent elements. A typical feature of the two-dimensional turbulence is that the energy becomes concentrated in organised large scale fluctuations. This fact ensures an intensive heat transfer on longer distances. Because of the anisotropy of the electromagnetic dissipation term vortices will be scarcely damped over long distances if their axes are aligned with the magnetic field lines [6]. For practical applications it is important to identify possibilities to promote the formation of such quasi-two-dimensional vortices in order to control the heat or mass transfer rate of the flow. It is well-known that the mentioned perturbations can be generated by rather specific means, for example, mechanical inserts or electrical currents between definitely arranged electrodes, etc..
In our experiments we force the turbulence intensity by mechanical means employing a grid of cylindrical bars or flat stripes. Due to the favourable material properties of the used liquid sodium we are able to extend the measurements into the region of high interaction parameters. In this way the obtained results complement the already existing knowledge about the two-dimensional MHD turbulence. The results concerning the measured turbulence intensity as a function of the interaction parameter N and the corresponding power spectral densities will be presented. Electrical potential probes were used to determine the velocity fluctuations. The measurements took place in two different test sections allowing either the variation of the axial distance between the turbulence promoter and the probe or the installation of special channel inserts in order to suppress the generation of the M-profile of the local velocity and to decrease the wall conductance ratio. The results obtained in both test sections will be compared and the influence of the altered boundary conditions onto the turbulent structure of the flow will be discussed.
  • Lecture (Conference)
    International Symposium on Turbulence, Heat and Mass Transfer, Nagoya, Japan, April 3-6, 2000

Publ.-Id: 2563 - Permalink


Improvement of the high temperature oxidation resistance of Ti50Al via ion implantation
Hornauer, U.; Richter, E.; Wieser, E.; Möller, W.;
  • Lecture (Conference)
    11th Int. Conf. on Ion Beam Modification of Materials, Amsterdam, the Netherlands, Aug. 31 - Sept. 4, 1998

Publ.-Id: 2562 - Permalink


Gettering of iron and oxygen at cavities formed by helium ion implantation in Czochralski and float-zone silicon
Kaschny, J. R.; Fichtner, P. F. P.; Yankov, R. A.; Fukarek, W.; Mücklich, A.; Kreißig, U.; Peeva, A.; Danilin, A. B.; Skorupa, W.;
  • Lecture (Conference)
    E-MRS´98, Strasbourg, June 16-19, 1998

Publ.-Id: 2561 - Permalink


Stabilizing the direct melt extraction of intermetallic fibres by magnetic fields
Cramer, A.; Gerbeth, G.; Bojarevics, A.; Gelfgat, Y.;
In the direct melt extraction process a quickly rotating wheel draws fibres out of a liquid metal pool which may contain any pure metal or alloy. One common application of such fibres is the production of highly porous metallic substrates, which, in the case of Ni-Al is ideally suited to serve as a highly heat- and corrosion-resistant catalyst carrier. But this demands the fibres to have diameters in the range of 50 to 100 microns and a small width distribution of their cross section. The main limitations of this process are due to turbulence within the melt and a wavy motion on the surface which both inhibit to fulfil these requirements.
Many patents are concerned with the stabilisation of the melt pool or at least of the contact region between metal surface and the extraction wheel. They propose submersing mechanical parts directly into, or placing them at least in close vicinity to the melt to avoid the non-stationary conditions produced by the turbulence within the liquid metal pool. Even made of heat resistant ceramics they suffer from corrosion or cracks and do not work reliable at all. The present work describes a non invasive control mechanism by means of magnetic fields of different strength and orientation. They can be applied either globally to damp the flow within the whole melt volume or locally to the meniscus region where the fibre is formed, to reach higher Lorentz forces in this very sensitive region. Model experiments (In-Ga-Sn, liquid at room temperature; no extraction) with global stabilisation were carried out to study the calm down of the turbulent surface of an inductively stirred melt. In a second setup the influence of this globally applied field on the fibres have been investigated (low melting Sn-Pb). Though the otherwise wavy surface was damped down to a nearly mirror-like plane the goal of significant smaller fibre cross-section was not reached by the global stabilisation alone. The clearly observable positive tendency towards smaller fibres is presently investigated with two series of model experiments with local stabilisation. The smaller volume which needs to be magnetised allows for a 5 times stronger field which can be achieved either by rare earth permanent magnets or a concentration of the globally applied field with magnetic field guides.
  • Lecture (Conference)
    The 3rd International Symposium on Electromagnetic Processing of Materials (EPM2000) April 3-6 / Nagoya, Japan, Published by: The Iron and Steel Institute of Japan, pp 147-152
  • Contribution to proceedings
    The 3rd International Symposium on Electromagnetic Processing of Materials (EPM2000) April 3-6 / Nagoya, Japan, Published by: The Iron and Steel Institute of Japan, pp 147-152

Publ.-Id: 2560 - Permalink


Characterization of vacancy-type defects in Al+ and N+ co-implanted SiC by slow positron implantation spectroscopy (SPIS)
Anwand, W.; Brauer, G.; Coleman, P. G.; Yankov, R. A.; Skorupa, W.;
  • Lecture (Conference)
    30th Polish Seminar on Positron Annihilation, Jarnoltowek, Sept. 17-21, 1998
  • Lecture (Conference)
    8th Int. Workshop on Slow Positron Beam Techniques for Solids and Surfaces (SLOPOS-8), Cape Town, Sept 6 - 12, 1998
  • Applied Surface Science 149 (1999) 140-143

Publ.-Id: 2559 - Permalink


Instabilities of electromagnetically levitated bodies and its prevention
Priede, J.; Gerbeth, G.; Mikelsons, A.; Gelfgat, Y.;
Electromagnetic levitation is a well-known technique for containerless processing of metals and alloys both in the solid and in the molten state. In experiments the levitated bodies often times show different types of instabilities resulting in a rotating and oscillating motion of the sample. In the paper we analyze the physical reasons for such spontaneous instabilities, and conclude on possible measures against it. The first type of instability considered is that due to possible coupling between the electric current passing through the magnetic system and the variation of position of the levitated body. It is shown that oscillatory motion of the body may be unstable if the electric power supply regime permits the electric current passing through the magnetic system to vary depending on its effective inductance. Another type of instabilities may occur because of the coupling between the motion of the body and the electric currents induced in the body itself. This effect may cause a spontaneous spin-up of the spherical body, occuring if the magnetic field frequency exceeds a certain critical threshold depending on the configuration of the field. It is shown that this type of linear instability may be completely suppressed by imposing a steady magnetic field of a strength comparable to that of the oscillating one. As a third type of instability we consider small vibrations of the spherical body occuring due to the finite diffusion time of the magnetic field into the body resulting in a delay of the induced currents with respect to the body position. Again, such vibrations may occur if the non-dimensional field frequency exceeds some specific threshold. This threshold and the
underlaying mechanism will be explained. The theoretical predictions are verified by model experiments using solid Al or Mg spheres. These instabilities can obviously be avoided by system parameters below the corresponding non-dimensional reshold. If this is not possible in reality, an active damping method using DC magnetic fields has been developed, too. The DC field can either be produced by permanent magnets or by an electromagnetic superposition to the levitation coils. Experiments will be shown demonstrating the stabilization effect due to the DC magnetic fields.
  • Lecture (Conference)
    The 3rd International Symposium on Electromagnetic Processing of Materials (EPM2000) April 3-6 / Nagoya, Japan, Published by: The Iron and Steel Institute of Japan, pp 352-357
  • Contribution to proceedings
    The 3rd International Symposium on Electromagnetic Processing of Materials (EPM2000) April 3-6 / Nagoya, Japan, Published by: The Iron and Steel Institute of Japan, pp 352-357

Publ.-Id: 2558 - Permalink


A New Criterion for the Bubble Slug Transition in Vertical Tubes
Krüssenberg, A.-K.; Prasser, H.-M.; Schaffrath, A.;
Vertical two-phase flow is normally classified into the four basic flow regimes bubble, slug, churn and annular flow. The transition between the different flow regimes does not occur suddenly and many extensions of this classification can be found in literature. For the prediction of flow patterns empirical and theoretical flow pattern maps have been developed.
A new criterion is presented for the transition between bubble and slug flow which is based on local instantaneous conductivity measurements with a wire mesh sensor (1 kHz that means 1000 frames per second, 242 measuring points in a tube cross section area). The high resolution allows the calculation of particle size distributions.
The transition from homogeneous bubble flow to heterogeneous bubble flow is indicated by the appearance of a bimodal bubble size distribution. If the equivalent bubble diameter exceeds the tube diameter the transition from bubble to slug flow occurs. The new criterion is compared with different empirical (Govier & Aziz, Weisman & Kang) and theoretical flow maps (Taitel, Bornea & Dukler, Ishii & Mishima) and shows a good agreement.

Keywords: Bubble Size Distribution, Bubble Slug Flow Transition Criteria
  • Kerntechnik 65/1 (2000) 7-13
  • Contribution to external collection
    NURETH-9, San Francisco, California, USA, October 3-8, 1999

Publ.-Id: 2557 - Permalink


Numerical Simulation of the Emergency Condenser of the SWR1000
Krepper, E.; Schaffrath, A.; Aszódi, A.;
The SWR1000 is a new innovative boiling water reactor concept, which is developed by Siemens AG. This concept is characterized in particular by passive safety systems (e.g. four emergency condensers, four building condensers, eight passive pressure pulse transmitters, six gravity-driven core flooding lines). In the framework of BWR Physics and Thermohydraulic Complementary Action (BWR-CA) to the EU BWR R&D Cluster emergency condenser tests were performed by Forschungszentrum Jülich at the NOKO test facility. In this paper post test calculations with ATHLET are presented, which aim at the determination of the removable power of the emergency condenser and its operation mode. The 1D thermal-hydraulic code ATHLET was extended by the module KONWAR for the calculation of the heat transfer coefficient during condensation in horizontal tubes. In addition, results of CFD-calculations using the code CFX-4 are presented, which investigate the natural convection during the heat up process at the secondary side of the NOKO test facility.
Keywords: BWR, emergency condenser, condensation inside horizontal tubes, natural convection, CFD
  • Kerntechnik 64 (1999) 5-6, p. 243-252

Publ.-Id: 2556 - Permalink


ROBL (German Beamline) on BM20: Structural and radiochemical investigations
Matz, W.; Schell, N.; Funke, H.; Bernhard, G.;
  • ESRF- Newsletter 30 (1998) 45

Publ.-Id: 2554 - Permalink


Rossendorfer Beamline an der ESRF
Matz, W.;
  • Phys. Bl. 54 (1998) Nr. 9, 785

Publ.-Id: 2553 - Permalink


Investigation of liquid metal two phase flow characteristics by means of local resistivity probes and X-ray screening technique
Eckert, S.; Gerbeth, G.; Guttek, B.; Stechemesser, H.; Lielausis, O.;
In many technologies such as the refinement of metallic melts the injection of gas bubbles is used to drive some liquid motion, enhance transport processes or to control the rate of chemical reactions. The resulting flow structure strongly depends on two phase flow parameters such as bubble size, bubble distribution or the local void fraction. Magnetic fields can be used to control the characteristics of a liquid metal bubbly flow.
We present experimental investigations of the bubble formation in heavy liquid metals as well as the influence of external magnetic fields on the turbulent dispersion of gas bubbles and the slip ratio in liquid metal bubbly flows, respectively.

a) Bubble formation
If gas bubbles are injected into a liquid metal characterised by a large surface tension one should be care to get a good wetting between the fluid and the surface of the gas injector. Otherwise, the gas would try to spread out along this interface to form gas layers. A control of the bubble size and formation rate becomes difficult. The comparison between experiment and theoretical models describing bubble formation processes requires an ideal wetted gas injector.
The bubble formation in mercury and the eutectic alloy InGaSn has been studied by means of several methods of gas injection, for instance through single orifices or injectors made from sintered metals with a mean porosity of a few microns. X-ray measurements have been used to directly observe the resulting gas bubbles rising in the liquid metal. In the case of an single orifce the influence of electromagnetic forces on the bubble frequency has been demonstrated.

b) Turbulent bubble dispersion, slip ratio
The transport properties of small argon bubbles have been studied in turbulent upwards channel flows of sodium and mercury. The bubbles were injected by a single orifice located in the centre of the channel cross section. After a distinct distance the local void fraction and the bubble velocity has been measured by means of electrical resistivity probes. The flow has been exposed to external magnetic fields directed transverse or longitudinal to the mean flow direction.
We will present and discuss measuring results showing the effect of the magnetic field strength and direction on the horizontal gas distribution and the ratio between gas and liquid velocity.
Keywords: two-phase flow, bubbly regime, liquid metals, void fraction measurements, electric resistivity probe, X-ray imaging
  • Lecture (Conference)
    International Workshop on Measuring Techniques for Liquid Metal Flows (MTLM), Dresden, October 11-13, 1999

Publ.-Id: 2552 - Permalink


Local velocity measurements in high temperature liquid metals by means of mechano-optical probes
Eckert, S.; Witke, W.; Pisseloup, L.; Gerbeth, G.;
Model experiments are an important tool to understand the details of the flow structure and the transport properties of
flows occurring in real-scale metallurgical facilities as well as to validate the multitude of numerical codes for flow
simulation. Generally, water experiments are often performed to characterise the flow. Nevertheless, due to the large
differences of material properties like density, heat conductivity, surface tension or electrical conductivity the use of liquid
metals has clearly to be preferred if heat transfer phenomena, two-phase flows or the influence of electromagnetic fields
on the flow should be investigated. The application of suitable alloys with low melting points, for instance PbBi (Tm = 125
°C) or InGaSn (Tm = 5...10 °C), makes such kind of experiments very flexible and offers the ability to measure the
essential flow quantities like velocity, pressure or void fraction.

In this lecture we want to discuss a novel sensor which has been developed by the Rossendorf group to measure the local
velocities in opaque liquid flows. The measuring principle is based on the separation of a direct mechanical interaction
between flow and sensor tip and the optical acquisition and processing of the signal. In principle, this fact allows the
extension of the range of applicability to higher temperatures. Furthermore, the insensitivity of the system to electrical
noise and external magnetic fields can be considered as an important advantage. Until now, the sensor has been tested in
metallic melts up to temperatures of about 350 °C . In principle, an extension of the range of application up to
temperatures of about 1100 °C should be possible by the utilisation of quartz glass as material for the sensitive sensor tips.
The first sensors have been manufactured and tested with low temperature melts.

We present measurements of the local velocity obtained in an eutectic InGaSn melt driven by a rotating magnetic field.
The interest is focussed on geometry and parameters relevant for crystal growth technologies and mixing processes in
metallurgical applications, respectively. Measured profiles of the azimuthal velocity have been obtained at different
frequencies and field amplitudes.
Keywords: flow measurement technique, fluid velocity, mechano-optical principle, local sensor, liquid metals, rotating magnetic field
  • Lecture (Conference)
    International Workshop on Measuring Techniques for Liquid Metal Flows (MTLM) , Dresden, October 11-13, 1999

Publ.-Id: 2551 - Permalink


Reaktorsicherheitsforschung im Institut für Sicherheitsforschung des Forschungszentrums Rossendorf
Weiß, F.-P.; Rohde, U.; Prasser, H.-M.; Altstadt, E.; Böhmert, J.; Böhmer, B.; Carl, H.;
Das Institut für Sicherheitsforschung ist eines von fünf wissenschaftlichen Instituten des Forschungszentrums Rossendorf e. V. (FZR). Die Rossendorfer Sicherheitsforschung baut auf langjährige Erfahrungen zur Analyse von Druckwasserreaktoren des russischen WWER-Types auf. WWER-Reaktoren nehmen bis heute einen wichtigen Platz im Spektrum des Institutes ein. So unterstützt das Institut im Rahmen eines Programmes des Bundesministeriums für Umwelt, Naturschutz, und Reaktorsicherheit die ukrainische Atomaufsichtsbehörde beim Aufbau einer modernen KKW-Überwachung. Inzwischen hat das Institut ebenso Kompetenz zur Sicherheitsforschung für westliche Leichtwasserreaktoren aufgebaut und kooperiert mit deutschen, europäischen und amerikanischen Forschungseinrichtungen und der Industrie.
Die Schwerpunkte der Sicherheitsforschung in Rossendorf liegen auf der Modellierung thermohydraulischer Phänomene bei unterstellten Störfallabläufen, der Reaktorphysik und dem Strahlungstransport und dem Verhalten von Komponenten und Materialien.
Der erste Teil des Forschungsberichtes beschäftigt sich ausschließlich mit den thermohydraulischen Arbeiten des Institutes wie den Vermischungsvorgängen im Primärkreis bei Borverdünnungs- und Kaltwassertransienten sowie der Modellentwicklung für transiente Zweiphasenströmungen. Für die thermohydraulischen Arbeiten hat das Institut ein 1:5 Modell eines deutschen DWR aufgebaut, die Experimente werden mit CFD-Codes (Computational Fluid Dynamics) nachgerechnet.
  • atw 44. Jg. (1999) Heft 6 - Juni, S. 348

Publ.-Id: 2550 - Permalink


Measuring techniques for model experiments in liquid metal alloys
Eckert, S.; Witke, W.; Gerbeth, G.;
Model experiments are an important tool to understand the details of the flow structure and the transport properties of flows occurring in real-scale metallurgical facilities as well as to validate the multitude of numerical codes for flow simulation. The application of suitable alloys with low melting points, for instance PbBi (T = 125 °C) or InGaSn (T = 5...10 °C), guarantees realistic flow parameters and also offers the ability to measure essential flow quantities like velocity, pressure or void fraction. Two approaches will be discussed to measure the local velocities in opaque liquid flows such as liquid metals: a mechano-optical sensor and the ultrasonic Doppler method, respectively. Today, with respect to problems like high temperatures or material compatibility both techniques reveal severe limitations considering velocity measurements in liquid steel or aluminium, however, their reliability at moderate temperatures has been demonstrated. Here, we present velocity measurements obtained by means of both methods for the case of a cylinder filled with an eutectic InGaSn melt driven by a rotating magnetic field.
Keywords: flow measurement technique, fluid velocity, mechano-optical principle, ultrasonic Doppler method, liquid metals, rotating magnetic field
  • Lecture (Conference)
    EPM2000, The 3rd International Symposium on Electromagnetic Processing of materials, April 3-6, Nagoya, Japan, Published by: The Iron and Steel Institute of Japan, pp. 43-48
  • Contribution to proceedings
    EPM2000, The 3rd International Symposium on Electromagnetic Processing of materials, April 3-6, Nagoya, Japan, Published by: The Iron and Steel Institute of Japan, pp. 43-48

Publ.-Id: 2549 - Permalink


Comparative Study of Methods to Estimate Elastic-Plastic Dynamic Fracture Initiation Toughness
Richter, H.;
There has not yet been generally accepted single specimen technique in order to obtain dynamic fracture mechanical parameters. A potential candidate could be the measurement of the acoustic emission (AE). Previous investigations showed that characteristic AE signals appears in the vicinity of crack initiation for the first time. With a specially developed measuring arrangement the method could be compared with simultaneously measuring additional physical parameters at specimens of strongly different levels of toughness and strength. Furthermore the results could be verified by the results of multiple specimens technique. With this technique the dynamic crack resistance curve was determined and the physical crack initiation toughness was deduced by measurement of the stretch zone width. To realize the idea the inverted impact pendulum developed and installed by VTT Espoo/Finland was modified with an AE transducer and a magnetic emission (ME) probe. The inverted impact pendulum design reduces the inertia and oscillation effects in the recorded load curve and allows to measure the crack opening (COD) by a laser scattering light method. In this way, at the same specimen crack opening displacement (COD), AE, and ME could be measured.
Neither of the three single specimen methods can directly detect crack initiation. Except the lower shelf region, were only a tiny amount of ductile crack growth occurs before cleavage, the stable crack initiation could be proven by AE and COD. Good agreement between initiation parameters based on SZW and AE was found for all toughness levels. In some cases a strong scattering of toughness parameters was, however, observed and the ranking did not correspond. COD indicates crack initiation after an amount of macroscopic stable crack growth, which is small but cannot be ignored. The correlation to the SZW is not independent of the toughness; for steels with high toughness the correlation is unsatisfied. Eventually, ME does not reflect stable crack initiation and growth.
Obviously, the physical connection between crack initiation and AE cannot be revealed. The AE method has been proved as very sensible for microscopically active processes, which coincide spatially and chronologically with ductile crack initiation. Thus, it is appropriate to estimate the dynamic fracture mechanical parameter "crack initiation toughness" better than other recently applied methods.
  • Lecture (Conference)
    Beitrag zu European Conference Junior Euromat‘98, 7.-11.9.1998, Lausanne, Switzerland, p. 333
  • Contribution to proceedings
    Beitrag zu European Conference Junior Euromat‘98, 7.-11.9.1998, Lausanne, Switzerland, p. 333

Publ.-Id: 2548 - Permalink


TRIDYN-Computersimulationen zur Schicht-Deposition von BN und zur Hochdosisimplantation in Si
Schwieger, T.;
  • Other report
    Friedrich-Schiller-Universität Jena, April 1997

Publ.-Id: 2547 - 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]