Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999
  • 1990-1994  (3)
  • 1992  (3)
Source
Material
Years
  • 1995-1999
  • 1990-1994  (3)
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Physical and numerical model study of diffraction effects on seismic profiles over simple structures (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 108 (1992), S. 0 
    Details
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: 2-D scale models and synthetic seismograms have been used to study diffraction artifacts and interpretation pitfalls on seismic profiles over two classes of simple-shaped structures: a vertical fault model and a rectangular mound model.The fault throw was varied from one eighth of a wavelength (λ/8) to two wavelengths (2λ). For throws greater than λ/2, the structure is resolved in the x-t domain but diffractions which are present convey misleading structure. Amplitude and wavelet anomalies are observed for small fault displacement (λ/2) which serve to detect but not to define the exact fault position and extent. Migration improves but does not necessarily overcome the problem.Mound structures having heights of λ/8 to 2λ, and length of one half to twice the Fresnel zone radius, were investigated. Lateral resolution is improved as the length of the structure increases, but only for mounds which are vertically resolved (height greater than λ/2). For low relief mounds, resolution deteriorates with increasing mound length. The resulting edge diffractions, which interfere with the reflection events, serve to detect and identify the target. Amplitude anomalies are observed across the structures, but it is not possible (without calibration) to interpret the edges of the model. Even for thick mounds the diffraction patterns complicate the seismic picture and can lead to false interpretation.The migration aperture needs to be about 10 times the Fresnel zone radius to produce satisfactory results. However, for vertically unresolved structures, migration may not significantly help. Complicating factors with post-stack migration are lack of knowledge of the true velocity function and inadequacy of the CMP zero-offset equivalence assumption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-246X.1992.tb03479.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Precision submillimeter wave laser reflection measurements of high-temperature superconductors (1992)
    Springer
    Journal of superconductivity 5 (1992), S. 389-393 
    Details
    ISSN: 1572-9605
    Keywords: Submillimeter wave ; laser ; reflection ; surface resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Submillimeter wave laser reflection measurements of surface resistance can provide improved capability in the combination of sensitivity, spatial resolution, and frequency range. We have made reflectivity measurements on metals at 1630 GHz with an uncertainty of less than 0.3%. This sensitivity corresponds to a measurement sensitivity for surface resistance of 0.3 Ω. Assuming anf 2 frequency scaling of high-temperature superconductor surface resistance from the microwave to the terahertz frequency range, this sensitivity corresponds to about 1 ×10−5 Ω at 10 GHz. Capability for 10−7 Ω sensitivity could eventually be possible. Preliminary submillimeter wave reflection measurements of a YBCO thin film have been made with a sensitivity of 1%. Submillimeter wave reflectometry can make it possible to determine the spatial dependence of surface resistance in a wide range of material sizes and shapes. The spatial resolution could be on the order of 0.3–0.5 mm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00618139
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Fabrication of carbon fibre-reinforced aluminium composites with hybridization of a small amount of particulates or whiskers of silicon carbide by pressure casting (1992)
    Springer
    Journal of materials science 27 (1992), S. 3617-3623 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An investigation was carried out on the fabrication of carbon fibre-reinforced aluminium matrix composites with hybridization of particulates or whiskers of silicon carbide by pressure casting. A small amount of particulates or whiskers was uniformly distributed among carbon fibres and the preforms prepared from the treated fibres were directly infiltrated by molten aluminium under applied stress. It was found that the longitudinal tensile strengths of hybrid composites were greatly improved, although their fibre volume fractions were very low compared to those of conventional composites. With this hybridization method, it is also practical to tailor the fibre volume fraction of composites from 60 to 25 vol %, which is not possible in direct infiltration of fibre preforms by pressure casting. The results obtained lead to the conclusion that particulate or whisker additions act not directly as reinforcements but as promoters to improve the infiltration performances of fibre preforms, and consequently to increase the strength-transfer efficiency of carbon fibres. The addition of particulates or whiskers can also improve other properties of the composites, such as hardness and wear resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01151841
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...