Search Results - (Author, Cooperation:J. Crowell)

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  1. 1
    Staff View
    Publication Date:
    2013-11-30
    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
    Keywords:
    *Access to Information ; Periodicals as Topic/*economics ; Research/*economics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Beebe, T. P. ; Crowell, J. E. ; Yates, J. T.

    College Park, Md. : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    We present experimental and calculated vibration–rotation spectra as a function of temperature for the methoxy species (–OCH3 and –OCD3) chemisorbed on an alumina surface. The axis of rotation is the C–O bond axis. The model for our calculations is that of free rotation, and we describe the methods employed here in full detail. The qualitative agreement between the calculated and experimental spectra suggests that the adsorbed methoxy species is undergoing free rotational motion about the C–O bond axis.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.458545

    Articles: DFG German National Licenses
  3. 3
    Crowell, J. E. ; Beebe, T. P. ; Yates, J. T.

    College Park, Md. : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    The physical adsorption of methyl chloride onto Al2O3 surfaces containing surface OH groups has been studied using transmission infrared spectroscopy. Methyl chloride reversibly bonds via hydrogen bonding to the surface hydroxyl groups with a spectroscopically measured heat of adsorption of −3.37±0.38 kcal mol−1. Physisorption of methyl chloride results in a significant reduction in the intensity of the rotational wings of the methyl chloride absorption bands relative to the gas phase, a small downward frequency shift in their band centers, and substantial effects on the ν(OH) region of the alumina spectrum due to hydrogen bonding of surface OH groups with methyl chloride. Fermi resonances are observed for adsorbed methyl chloride and result in the observation of the overtones of both the symmetric and asymmetric methyl deformation modes. It is postulated that the hydrogen-bonded CH3Cl species possess rotational (or other) degrees of freedom which lead to a high entropy in the adsorbed layer, compared to the liquid.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.452964

    Articles: DFG German National Licenses
  4. 4
    Crowell, J. E. ; Chen, J. G. ; Hercules, D. M. ; Yates, J. T.

    College Park, Md. : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    The adsorption of water on both clean and oxygen-predosed Al(111) has been studied by vibrational spectroscopy using electron energy loss spectroscopy (EELS). At 130 K, adsorption on either surface is competitively associative and dissociative. The dominant dissociation product is a hydroxyl species. On the clean surface, adsorption is predominantly molecular, while in the presence of oxygen, adsorption is predominantly dissociative. In contrast to the low temperature behavior, adsorption of water on clean Al(111) at 300 K is completely dissociative, resulting in oxygen adsorption and surface oxidation. Adsorbed hydroxyl species can be produced at 300 K by prolonged water exposure. Upon heating a low-temperature water layer adsorbed on either surface, molecular water desorption and further decomposition both occur. The production of adsorbed hydroxyl species from water reaches a maximum at 250 K on the clean surface and at 350 K on the oxygen-predosed surface. The hydroxyl species decompose above these temperatures to evolve hydrogen and further oxidize the Al(111) surface.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.452510

    Articles: DFG German National Licenses
  5. 5
    Crowell, J. E. ; Chen, J. G. ; Yates, J. T.

    College Park, Md. : American Institute of Physics (AIP)
    Published 1986
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    The adsorption and decomposition of formate and formic acid have been studied on the Al(111) surface using high resolution electron energy loss spectroscopy (EELS) and temperature programmed desorption (TPD). Formic acid reacts with clean Al(111) at 120 K to form a surface formate species. Molecular adsorption of formic acid occurs at 120 K only after saturation of the surface formate layer has been reached. Off-specular vibrational measurements have determined that the formate species is symmetrically bridge bonded through both oxygen atoms with C2v symmetry. A lower symmetry formate species of C1 symmetry is produced upon heating or electron bombardment of a condensed formic acid layer. Thermal or electron induced decomposition of a formate or a condensed formic acid layer is controlled by oxygen incorporation into the aluminum lattice, and results in complete decomposition and production of a carbon and oxygen covered surface. Only hydrogen is evolved from a formate-covered Al(111) surface.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.451020

    Articles: DFG German National Licenses
  6. 6
    Chen, J. G. ; Crowell, J. E. ; Yates, J. T.

    College Park, Md. : American Institute of Physics (AIP)
    Published 1986
    Staff View
    ISSN:
    1089-7690
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Chemistry and Pharmacology
    Notes:
    The adsorption of water on a well-characterized Al2O3 film produced by oxidizing an Al(111) surface has been studied using electron energy loss spectroscopy (EELS). Water reacts with this oxide layer to form surface hydroxyl species characterized by a sharp O–H (O–D) stretching vibration at 3720 (2740) cm−1. The assignment of the three-peak vibrational spectrum of Al2O3 to surface and bulk Al–O modes is confirmed by chemical means based on the observation that the 625 cm−1 loss feature assigned to a surface Al–O stretching vibration is preferentially affected upon formation of surface hydroxyl groups. The remaining two bulk modes are uninfluenced by surface hydroxylation. The surface hydroxyl species can be quantitatively removed by electron stimulated desorption (ESD), reversing the spectroscopic changes observed upon exposure of Al2O3 to water, further substantiating the vibrational assignments.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.449902

    Articles: DFG German National Licenses
  7. 7
    Staff View
    ISSN:
    0022-5320
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/S0022-5320(82)90012-0

    Articles: DFG German National Licenses
  8. 8
    Mullaney, P. F. ; Steinkamp, J. A. ; Crissman, H. A. ; Cram, L. S. ; Crowell, J. M. ; Salzman, G. C. ; Martin, J. C.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1976
    Staff View
    ISSN:
    1749-6632
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Natural Sciences in General
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1749-6632.1976.tb41607.x

    Articles: DFG German National Licenses
  9. 9
    Abromson-Leeman, S. R. ; Laning, J. C. ; Crowell, J. ; Dorf, M. E.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1988
    Staff View
    ISSN:
    1744-313X
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Biology
    Medicine
    Notes:
    Among T cell clones with specificity for cow insulin and autologous class II MHC products, a significant number displayed interesting patterns of alloreactivity to non-MHC antigens. Four clones are described in this report. One is a typical Mlsa-reactive clone, while the other three proliferate to a variety of allogeneic spleen cells with reportedly different Mls phenotypes. These include PL/J stimulator cells, designated Mlsx all strains reported to be Mlsc, and several strains previously typed as Mlsa. Little is known about Mlsx except that it does not appear to be cross-reactive with Mlsa. In this report, therefore, we attempt to investigate the reasons why these clones seem to be stimulated by a variety of different Mls phenotypes. Our conclusions are, first, that some of the strains previously typed as Mlsa may actually express a second Mls product, either c or x, in a manner analogous to the CBA/J strain (which expressess both Mlsa and Mlsc), and second, that Mlsc and Mlsx are cross-reactive. In preliminary experiments, we investigate the genetic relationship between Mlsc and Mlsx by analysis of backcrosses, and the extent of cross-reactive recognition of Mlsc and Mlsx by raising T cell clones which recognize one but not the other. Our preliminary conclusion is that Mlsc and Mlsx are cross-reactive, but represent distinct gene products.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1744-313X.1988.tb00404.x

    Articles: DFG German National Licenses
  10. 10
    Staff View
    ISSN:
    0042-207X
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0042-207X(83)90631-0

    Articles: DFG German National Licenses