Search Results - (Author, Cooperation:K. M. Leung)

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  1. 1
    Staff View
    Publication Date:
    2012-10-30
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Aquatic Organisms/cytology/metabolism/ultrastructure ; Deltaproteobacteria/cytology/*metabolism/ultrastructure ; Denmark ; *Electric Conductivity ; Electron Transport ; Geologic Sediments/microbiology ; Glass ; Microspheres ; Molecular Sequence Data ; Molecular Typing ; Oceans and Seas ; Oxygen/metabolism ; Porosity ; RNA, Ribosomal, 16S/analysis/genetics ; Sulfides/metabolism
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Qiu, Y. ; Leung, K. M. ; Carin, L. ; Kralj, D.

    [S.l.] : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    An on-shell method that combines plane-wave and finite-difference techniques for the calculation of dispersion curves and transmission spectra for electromagnetic fields in photonic band-gap crystals is presented. The overall problem is decomposed into a field problem of determining the plane-wave scattering from an individual crystalline layer and a conventional one-dimensional network problem of combining this scattering to obtain the band structure of the entire crystal or the scattering properties of a crystal with a finite thickness. Results of the calculation are compared with experimental data measured using ultrawideband microwave pulses for a two-dimensional photonic band-gap crystal. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.358599

    Articles: DFG German National Licenses
  3. 3
    Yu, D. P. ; Sun, X. S. ; Lee, C. S. ; Bello, I. ; Lee, S. T. ; Gu, H. D. ; Leung, K. M.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1998
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Boron nitride nanotubes (BN-NTs) were synthesized by using excimer laser ablation at 1200 °C in different carrier gases. The main characteristic of the BN-NTs produced by this method is that nanotubes are of only one to three atomic layers thick, which could be attributed to the dominance of the axial growth rate over the radial growth rate. The diameter of the BN-NTs ranged from 1.5 to 8 nm. The tips of the BN-NTs are either a flat cap or of polygonal termination, in contrast to the conical ends of carbon nanotubes. The atomic ratio of boron to nitrogen as measured by means of parallel electron energy loss spectroscopy is 0.8, which is within the experimental error of the stoichiometry of hexagonal BN structure. © 1998 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.121236

    Articles: DFG German National Licenses
  4. 4
    Lin, L. ; Tamir, T. ; Leung, K. M.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    By using the resonance property of modal fields, we derive leaky-wave modes supported by nonlinear layered media of the Kerr type and apply the results to obtain the beam field emitted by an output prism coupler containing such a nonlinear layer.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.101886

    Articles: DFG German National Licenses
  5. 5
    Wang, S. C. ; Leung, K. M. ; Gacusan, L. Z.

    [S.l.] : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A single-longitudinal-mode oscillation has been observed for the gain-guided GaAlAs laser arrays under controlled conditions. These multiple-element laser arrays were operated under continuous-wave conditions with controllable temperatures and currents. We have observed single-longitudinal-mode operation at near threshold and above threshold for operating temperatures of 10–37 °C. A mode intensity ratio of over 50:1 was observed with fairly stable output. In addition, a single-lobed far-field pattern under single-mode oscillation was also observed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.337905

    Articles: DFG German National Licenses
  6. 6
    Leung, K. M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Theoretical studies by Hinchey and Mills [J. Appl. Phys. 57, 3687 (1985)] on the basic properties of magnetic superlattice structures formed from alternating layers of ferromagnetic and antiferromagnetic materials have revealed a number of fascinating results. In their model, the antiferromagnet consists of sheets parallel to each interface within which the spins are aligned ferromagnetically. A localized spin model with only nearest-neighbor interaction is assumed. In this work we work with the same model, but in the absence of an applied magnetic field. The low temperature magnetic properties are investigated theoretically within the spin-wave approximation. For arbitrary thicknesses of ferromagnetic and antiferromagnetic layers, an expression which determines the dispersion relation for the spin-wave modes is obtained. The transformation from spin deviations variables to these modes is also computed explicitly.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.338530

    Articles: DFG German National Licenses
  7. 7
    Leung, K. M. Y. ; Chu, J. C. W. ; Wu, R. S. S.

    Oxford, UK : Blackwell Science Ltd
    Published 1999
    Staff View
    ISSN:
    1365-2109
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1046/j.1365-2109.1999.00391.x

    Articles: DFG German National Licenses
  8. 8
    Staff View
    ISSN:
    1572-817X
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Electrical Engineering, Measurement and Control Technology
    Physics
    Notes:
    Abstract Three-dimensionally periodic dielectric structures, (photonic crystals), possessing a forbidden gap for electromagnetic wave propagation, (a photonic bandgap), are now known. If the perfect 3-dimensional periodicity is broken by a local defect, then local electromagnetic modes can occur within the forbidden bandgap. The addition of extra dielectric material locally, inside the photonic crystal, produces ‘donor’ modes. Conversely, the local removal of dielectric material from the photonic crystal produces ‘acceptor’ modes. It will now be possible to make high-Q electromagnetic cavities of volume ∼ 1 cubic wavelength, for short wavelengths at which metallic cavities are useless. These new dielectric cavities can cover the range all the way from millimeter waves, down to ultraviolet wavelengths.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00625828

    Articles: DFG German National Licenses
  9. 9
    YABLONOVITCH, E. ; LEUNG, K. M.

    [s.l.] : Nature Publishing Group
    Published 1991
    Staff View
    ISSN:
    1476-4687
    Source:
    Nature Archives 1869 - 2009
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Notes:
    [Auszug] SIR - The search for photonic bandgaps has not bitten the dust, John Maddox suggests1. We have recently created three-dimension-ally periodic dielectric structures which are to photon waves as semiconductor crystals are to electron waves. That is, these photonic crystals have a photonic bandgap, a ...
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1038/351278a0

    Articles: DFG German National Licenses
  10. 10
    Ling, Shi ; Weining, Wang ; Fulong, Dai ; Leung, K. M.
    Springer
    Published 1996
    Staff View
    ISSN:
    0894-9166
    Keywords:
    holographic interferometry ; moire interferometry ; SMT assembly ; power cycling
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Physics
    Notes:
    Abstract The three-dimensional displacement fields of thermal-force coupling fatigue in a surface mounted plastic-quad-flat-pack (PQFP) assembly during power cycling by using the combination of holographic interferometry and high sensitivity moire interferometry is presented in this paper. Detailed in-plane and out-of-plane whole-field displacement data of the top and bottom ends of gull wing leads and their distributions along the edge of PQFP are provided. It was found that the maximum deformations of gull wing leads occur at the four corners of PQFP. The result presented herein should be useful in the evaluation of thermal fatigue damage mechanism of surface mount assemblies.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF02206459

    Articles: DFG German National Licenses