Search Results - (Author, Cooperation:B. Hammer)

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  1. 1
    T. L. Jacobsen, M. S. Jørgensen, and B. Hammer
    American Physical Society (APS)
    Published 2018
    Staff View
    Publication Date:
    2018-01-13
    Publisher:
    American Physical Society (APS)
    Print ISSN:
    0031-9007
    Electronic ISSN:
    1079-7114
    Topics:
    Physics
    Keywords:
    Condensed Matter: Structure, etc.
    Published by:
    http://www.aps.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    V. Demers-Carpentier ; G. Goubert ; F. Masini ; R. Lafleur-Lambert ; Y. Dong ; S. Lavoie ; G. Mahieu ; J. Boukouvalas ; H. Gao ; A. M. Rasmussen ; L. Ferrighi ; Y. Pan ; B. Hammer ; P. H. McBreen
    American Association for the Advancement of Science (AAAS)
    Published 2011
    Staff View
    Publication Date:
    2011-11-15
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Kratzer, P. ; Hammer, B. ; Nørskov, J. K.

    College Park, Md. : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    We present a density functional theory study of the first step of CH4 adsorption on the Ni(111) surface, dissociation into adsorbed CH3 and H. The rupture of the C–H bond occurs preferentially on top of a Ni atom, with a dissociation barrier of about 100 kJ/mol (including zero point corrections). The transition state involves considerable internal excitation of the molecule. The active C–H bond is both stretched to 1.6 A(ring) and tilted relative to the methyl group. A normal mode analysis shows that the reaction coordinate is mainly a C–H stretch, while the orientation of the C–H bond relative to the surface is responsible for the highest real mode. Alloying the surface with gold also affects the reactivity of the Ni atoms on adjacent surface sites. The dissociation barrier is increased by 16 and 38 kJ/mol for a Ni atom with one or two gold neighbors, respectively. We attribute these changes to a shift in the local density of d states at the nickel atoms in the neighborhood of gold. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.472399

    Articles: DFG German National Licenses
  4. 4
    Gottschalck, J. ; Hammer, B.

    College Park, Md. : American Institute of Physics (AIP)
    Published 2002
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    We have studied the adsorption of sulfur (S(Double Bond)), mercapto (HS–), and methylthiolate (CH3S–) on Au(111). The three adsorbates are found to form strong bonds to the gold surface through the S-end. While the sulfur atom adsorbs in the high coordinated fcc site, the mercapto and methylthiolate molecules adsorb in bridge or bridgelike sites. The bending of the sulfur–hydrogen and sulfur–methyl bonds away from the surface normal plays a key role in this sites preference. We show that the back bonded sulfur species prefer the bridge sites because of lower steric repulsion at these sites between the gold surface and the hydrogen and methyl groups, respectively. © 2002 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1424292

    Articles: DFG German National Licenses
  5. 5
    Kutsovsky, Y. E. ; Scriven, L. E. ; Davis, H. T. ; Hammer, B. E.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7666
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Spatially resolved velocity profiles and spatially nonresolved velocity distributions of steady flow in a tube and bead packs were measured. Two different NMR experiments were used to measure velocity distributions. In one, the velocity histogram was calculated from spatially resolved velocity phase encoded images acquired in a 6 mm bead pack. In the other, a Fourier flow method was used to measure the velocity distribution directly in a 0.25 mm bead pack. Axial velocity profiles in the pore space of the 6 mm bead pack at Reynolds numbers of 14.9, 29.9, and 44.8 proved to be roughly parabolic, with maxima near the pore centers. Both NMR methods yielded the same dimensionless velocity distributions that contain negative as well as positive velocity components. The velocity distribution function derived from a bundle-of-tubes-model accounts for the positive part of the velocity distribution. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.868867

    Articles: DFG German National Licenses
  6. 6
    HOECKER, W. H. ; HAMMER, B. W.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1944
    Staff View
    ISSN:
    1750-3841
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1365-2621.1944.tb16688.x

    Articles: DFG German National Licenses
  7. 7
    HUSSONG, R. V. ; HAMMER, B. W.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1944
    Staff View
    ISSN:
    1750-3841
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1365-2621.1944.tb16689.x

    Articles: DFG German National Licenses
  8. 8
    BABEL, F. J. ; HAMMER, B. W.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1939
    Staff View
    ISSN:
    1750-3841
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1365-2621.1939.tb17111.x

    Articles: DFG German National Licenses
  9. 9
    Staff View
    ISSN:
    0039-6028
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0039-6028(93)90910-C

    Articles: DFG German National Licenses
  10. 10
    Brunner, H. ; Eder, R. ; Hammer, B. ; Klement, U.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0022-328X
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0022-328X(90)87254-B

    Articles: DFG German National Licenses
  11. 11
    Hammer, B. ; Jacobsen, K.W. ; Norskov, J.K.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0039-6028
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0039-6028(93)90007-7

    Articles: DFG German National Licenses
  12. 12
    Staff View
    ISSN:
    0039-6028
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0039-6028(94)90759-5

    Articles: DFG German National Licenses
  13. 13
    Kratzer, P. ; Hammer, B. ; Norskov, J.K.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0009-2614
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0009-2614(94)01100-1

    Articles: DFG German National Licenses
  14. 14
    Staff View
    ISSN:
    0304-4165
    Keywords:
    (Bacteria) ; Heat resistance ; Spore stability ; ^1H-NMR
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0304-4165(81)90201-4

    Articles: DFG German National Licenses
  15. 15
    Hammer, B. ; Riediger, C. ; Hastenrath, M. ; Bolling, F.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0304-8853
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0304-8853(92)91141-F

    Articles: DFG German National Licenses
  16. 16
    Hammer, B. ; Nielsen, O.H. ; Nrskov, J.K.
    Springer
    Published 1997
    Staff View
    ISSN:
    1572-879X
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Chemistry and Pharmacology
    Notes:
    Abstract The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one structure to the next. We propose a model to explain this behavior, and use it to discuss more generally the origin of structure sensitivity in heterogeneous catalysis.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1023/A:1019073208575

    Articles: DFG German National Licenses
  17. 17
    Staff View
    ISSN:
    1434-3940
    Keywords:
    Schlüsselwörter Orbitarekonstruktion ; Resorbierbare Implantate ; Polylaktat ; Key words Orbital reconstruction ; Biodegradable implants ; Polylactide
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Description / Table of Contents:
    Summary In a complex animal model in sheep, polydioxanone (PDS®) and polylactic membranes were used for the reconstruction of large orbital-wall defects. In a long-term experiment over 1 year, polylactic implants alone showed the best performance as compared with combinations involving autogenous bone grafts and titanium miniplate fixation. As soon as these polylactic implants are approved for human surgery, they will be used to solve the still challenging problem of anatomical reconstruction of large comminuted fractures of more than one orbital wall.
    Notes:
    Zusammenfassung In einem experimentellen Modell wurden biodegradierbare Membranen aus Polydioxanon (PDS ® ) resp. Polylaktat zur Rekonstruktion großer Orbitawanddefekte bei Schafen verwendet. Im Langzeitversuch über ein Jahr zeigten diejenigen Rekonstruktionen die besten Resultate, bei welchen ausschließlich biodegradierbare Implantate aus Polylaktat zur Anwendung kamen. Bei gleichzeitiger Verwendung von autologen Knochentransplantaten und Titan-Miniplatten-Osteosynthesen war die anatomische Form der rekonstruierten Orbita weniger zuverlässig gewährleistet. Es darf erwartet werden, dass die klinische Zulassung der Polylaktat-Implantate die chirurgische Wiederherstellung ausgedehnter Trümmerfrakturen mehrerer Orbitawände wesentlich erleichtern wird und zu vorhersehbaren, anatomischen Rekonstruktionen führt.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/PL00014455

    Articles: DFG German National Licenses
  18. 18
    Hammer, B. ; Landolt, A. M.
    Springer
    Published 1966
    Staff View
    ISSN:
    1420-9071
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Medicine
    Notes:
    Summary Electrical impedance and outside tip diameter of glass microelectrodes were measured. With outside tip diameters smaller than 0.7μ there was a significant deviation between calculated and measured values. The relationship between outside tip diameter and wall thickness was investigated electronmicroscopically on micropipettes filled with phosphotungstic acid.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01901173

    Articles: DFG German National Licenses
  19. 19
    Staff View
    ISSN:
    1572-879X
    Keywords:
    active sites ; surface alloys ; STM ; molecular beams ; activation barriers
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Chemistry and Pharmacology
    Notes:
    Abstract This report describes a combined experimental and theoretical approach to the problem of designing surface alloys with specific chemical properties. Au-Ni(111) surface alloys were prepared and the distribution of active sites was determined by atomically resolved STM as a function of Au coverage. Using density functional theory the difference in activation energy for methane over the various sites was determined. The activity of the surface could be predicted directly by combining this information with the distribution of sites. Subsequent measurements of the activity proved this method to be quantitative and demonstrated that surface alloys with specific activity can be synthesized.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00815272

    Articles: DFG German National Licenses
  20. 20
    Staff View
    ISSN:
    1572-879X
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Chemistry and Pharmacology
    Notes:
    Abstract The structure and bonding in small MoS2 structures with and without Co is studied theoretically using self-consistent density functional theory with a non-local exchange-correlation energy. The structures model the catalysts used extensively in hydrotreating. We study in detail the structure and binding energies as a function of the amount of sulfur. The calculations show that extensive reconstructions occur at the two types of MoS2 edges where the sulfur dimerizes and occupies non-lattice positions. These structures are shown to be in good agreement with available experimental data. We also study the energy required to form sulfur vacancies, which are believed to be the active sites for many hydrotreating reactions. The presence of Co atoms at the edges is shown to lead to a significant lowering of the metal-sulfur binding energy. This imposes an increase in the concentration of active sites for the reactions and may thus explain the promoting effect of Co.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1023/A:1019009105792

    Articles: DFG German National Licenses