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  • 1
    Electronic Resource
    Electronic Resource
    The relativistic Hartree–Fock X-ray and electron form factors for mercury (1967)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 22 (1967), S. 153-153 
    Details
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0365110X67000246
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  • 2
    Electronic Resource
    Electronic Resource
    Relativistic Hartree–Fock X-ray and electron scattering factors (1968)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 24 (1968), S. 390-397 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Kinematic X-ray and electron scattering factors, found with the use of relativistic Hartree–Fock atomic fields, are tabulated for 76 atoms and ions. Parametric fits to these are given in the range of sin θ/λ from 0.0 to 2.0 Å−1. A method is developed to obtain the electron structure factor for forward scattering for a crystal containing ionized atoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739468000756
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Dynamical calculation of electron scattering by plasmons in aluminum (1971)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 27 (1971), S. 109-116 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Plasmon diffuse scattering (PDS) is calculated for Al(111) systematics using the multi-slice approach to dynamical electron scattering. It is found that PDS contributes strongly to Kikuchi bands, and to the decrease in the mean absorption coefficient which occurs when energy filtering is removed. Thickness fringes are found, which are similar to those for Bragg beams except at low thickness. The different behaviour in this region is explained. The effect of the (111) Kikuchi band on the variation of the path length for plasmon excitation with crystal tilt is considered in detail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739471000238
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  • 4
    Electronic Resource
    Electronic Resource
    Absorption coefficients for Al 111 systematics: theory and comparison with experiment (1970)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 26 (1970), S. 133-139 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Simple physical models are taken to calculate thermal and electronic contributions to absorption coefficients in Al. N-beam systematic calculations are interpreted by means of 2-beam theory, making possible a comparison with the experimental values of Watanabe. The mean absorption coefficient agrees to within 25 per cent. Spherical aberration and thermal diffuse scattering within the objective aperture are shown to explain the poorer agreement for the anomalous absorption coefficient. It is concluded that weak beams are significant in the measurement of absorption coefficients. Weak systematic beams are shown to have a significant effect on the positions of the thickness fringe maxima. A brief comparison of 2- and N-beam rocking curves is given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739470000190
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  • 5
    Electronic Resource
    Electronic Resource
    Dynamical calculation of thermal diffuse electron scattering (1969)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 25 (1969), S. 569-577 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The theory of Cowley & Pogany (Acta Cryst. (1968). A24, 109) is used for the numerical calculation of thermal diffuse electron scattering from thin monatomic crystals, along the line of a set of systematic reflexions. Dynamical interactions of 15 Bragg and 25 diffuse beams are considered for up to 183 Å of gold (200) systematics, treating the range of coherence of the interaction as a parameter of calculation. A one-phonon Debye model is used. It is found that thermal diffuse scattering will not produce strong thickness fringe contrast, but will yield Kikuchi bands and lines, with little dependence on the range of coherent interaction. The unindexed Kikuchi line at the centre of the bands is predicted. Thermal scattering tends to increase in the region of strong Bragg beams for tilted crystals. Compared to that predicted kinematically, dynamical thermal scattering is greater for thin crystals near principal orientations, but will in general be less for highly tilted and particularly for thick crystals; it is more spread out in the diffraction pattern, and far stronger in the first Brillouin zone. There is an indication that thermal streak patterns from thin crystals should be stronger than expected kinematically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739469001215
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrasonic leaky interface waves for composite-metal adhesive bond characterization (1995)
    Springer
    Journal of nondestructive evaluation 14 (1995), S. 49-59 
    Details
    ISSN: 1573-4862
    Keywords: Ultrasonic leaky waves ; laser ultrasonics ; weak adhesive bonds ; boron-epoxy composite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Highly stressed or damaged regions in aircraft structures are increasingly being reinforced by adhesively bonding an overlay of a unidirectional boron fiber-epoxy composite to the aircraft metallic substrate. While conventional C-scan ultrasonics can be used to detect disbonding of the overlay, nondestructive methods are also required to detect weak adhesive bonding. This paper describes a preliminary experimental investigation of the existence of ultrasonic leaky interface waves between overlays and 2024-T351 aluminum alloy and D6ac steel substrates, and their possible use for detection of weak bonds. The approach used was to excite these leaky waves using Rayleigh waves generated by a laser line-source on the substrate. The existence of the leaky waves, traveling normal to the composite fibers, between boron-epoxy overlays and either an aluminum or steel substrate, was confirmed by observations of the quasishear pulses leaked to the top of the overlay, and of the Rayleigh wave transmitted to the free surface beyond the overlay. When quantitative measurements were possible, measured values of the complex interface wave speed agreed satisfactorily with predicted values. This paper also demonstrates one case for which leaky interface waves are sensitive to weak bonding caused by the presence of a contaminant on the substrate surface prior to bonding: application of a low-concentration aqueous solution of hydraulic oil to the aluminum substrate prior to bonding of the overlay caused a marked increase, over that for the well-bonded case, in the observed amplitude of the quasi-shear pulses leaked to the top of the overlay by decay of the interface wave. More experiments are needed to establish whether leaky interface waves are sensitive to bond condition for various other combinations of substrate, overlay and contaminant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00735534
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  • 7
    Electronic Resource
    Electronic Resource
    Depth measurement for cracks in corners using ultrasonic Rayleigh waves (1986)
    Springer
    Journal of nondestructive evaluation 5 (1986), S. 179-187 
    Details
    ISSN: 1573-4862
    Keywords: Ultrasonic Rayleigh waves ; crack depth measurement ; corner cracks ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The scattering of ultrasonic Rayleigh waves incident normally on corners containing cracks is considered by using elastodynamic ray theory. Detailed calculations are presented for vertical and horizontal cracks in right-angle corners in aluminium. It is shown that crack depth can be measured simply from the spacing of interference fringes in the high-frequency spectra of either the back- or forward-scattered Rayleigh waves, given only a knowledge of the Rayleigh wave speed. Use of the back-scattered wave is preferable because its fringes show stronger modulation, and because an experiment requires a single transducer and access to only one face of the specimen. The technique is applicable without modification to the more general case of a crack at any angle in a corner of any angle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570627
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  • 8
    Electronic Resource
    Electronic Resource
    Calculation of ultrasonic surface waves from an extended thermoelastic laser source (1989)
    Springer
    Journal of nondestructive evaluation 8 (1989), S. 147-164 
    Details
    ISSN: 1573-4862
    Keywords: Ultrasonic surface waves ; Rayleigh waves ; laser ultrasonics ; thermoelastic ultrasonic source ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A method is developed to calculate ultrasonic surface waveforms generated by an extended laser source, operating in the thermoelastic regime of laser-pulse energy density. This approach integrates over a suitably weighted distribution of point surface centers of expansion, for observation to within 1 mm of the edge of the source. Power spectra as well as both horizontal and vertical displacements are presented and discussed for ultrasonic waveforms on an aluminium surface, for incident laser pulses having Gaussian lateral profiles of various sizes. Far from the source, the waveform is dominated by a dipolar Rayleigh (R) wave, whose amplitude and spectral content depend on laser spot size. Weak, monopolar pulses also occur at the intersection of bulk pressure and shear wavefronts with the surface (denoted assP andsS, respectively). Close to the source, thesP wave amplitude approaches that for theR wave, and overlaps theR wave for large source sizes. The fall-off with distance for bothsP andR waves is given. Finally, the changes in pulse shape and amplitude are calculated when anR wave from an extended thermoelastic source is reflected or transmitted by a right-angled corner of an aluminium block.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570884
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