Radiometry and wide-angle wave fields II Coherent fields in three dimensions

2001 ◽  
Vol 18 (4) ◽  
pp. 910 ◽  
Author(s):  
M. A. Alonso
Keyword(s):  
Three Dimensions ◽  
Wide Angle ◽  
Wave Fields

Wave fields in three dimensions: analysis and synthesis

1996 ◽  
Vol 13 (9) ◽  
pp. 1837 ◽  
Author(s):  
Rafael Piestun ◽  
Boris Spektor ◽  
Joseph Shamir
Keyword(s):  
Three Dimensions ◽  
Wave Fields ◽  
Analysis And Synthesis

Radiometry and Wide-Angle Wave Fields

2001 ◽  
Vol 12 (12) ◽  
pp. 52 ◽  
Author(s):  
Miguel A. Alonso
Keyword(s):  
Wide Angle ◽  
Wave Fields

Discrete wave-number representation of seismic-source wave fields

1977 ◽  
Vol 67 (2) ◽  
pp. 259-277
Author(s):  
Michel Bouchon ◽  
Keiiti Aki
Keyword(s):  
Layered Medium ◽  
Near Field ◽  
Seismic Source ◽  
Three Dimensions ◽  
Wave Number ◽  
Number Representation ◽  
Wave Fields ◽  
High Acceleration ◽  
Horizontal Wave ◽  
Source Wave

Abstract A method based on a discrete horizontal wave-number representation of seismic-source wave fields is developed and applied to the study of the near-field of a seismic source embedded in a layered medium. The discretization results from a periodicity assumption in the description of the source. The problem is basically two-dimensional but its extension to three dimensions is sometimes feasible. The source is quite general and is represented through its body-force equivalents. Tests of the accuracy of the method are made against Garvin's (1956) analytical solution (a buried line source in a half-space) and against Niazy's (1973) results for a propagating fault in an infinite medium. In both cases, a remarkably good agreement is found. The method is applied to the modeling of the San Fernando earthquake, and to the computation of synthetic seismograms at short distance from a complex source in a layered medium. In particular, we show that the high acceleration-high frequency phase of the Pacoima Dam records is due to the Rayleigh wave from the point of ground breakage. Other high-acceleration phases, predicted by our model, are associated with the shear-wave arrival from the hypocenter or result from changes in the fault orientation.

scholarly journals Perfect focusing of scalar wave fields in three dimensions

2010 ◽  
Vol 18 (8) ◽  
pp. 7650 ◽  
Author(s):  
Pablo Benítez ◽  
Juan C. Miñano ◽  
Juan C. González
Keyword(s):  
Three Dimensions ◽  
Scalar Wave ◽  
Wave Fields

CBED Shadow Images and Cs:Aberration Measurement

1982 ◽  
Vol 40 ◽  
pp. 696-697
Author(s):  
R. W. Carpenter ◽  
I.Y.T. Chan ◽  
J. M. Cowley
Keyword(s):  
Focal Point ◽  
Spherical Aberration ◽  
Optic Axis ◽  
Wide Angle ◽  
Caustic Surface ◽  
Convergent Beam

Wide-angle convergent beam shadow images(CBSI) exhibit several characteristic distortions resulting from spherical aberration. The most prominent is a circle of infinite magnification resulting from rays having equal values of a forming a cross-over on the optic axis at some distance before reaching the paraxial focal point. This distortion is called the tangential circle of infinite magnification; it can be used to align and stigmate a STEM and to determine Cs for the probe forming lens. A second distortion, the radial circle of infinite magnification, results from a cross-over on the lens caustic surface of rays with differing values of ∝a, also before the paraxial focal point of the lens.

High-resolution scanning electron microscopy (HRSEM) of mitochondria from various rat tissues

1988 ◽  
Vol 46 ◽  
pp. 14-15
Author(s):  
P.J. Lea ◽  
M.J. Hollenberg
Keyword(s):  
Electron Microscopy ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Rat Hepatocytes ◽  
Three Dimensions ◽  
Objective Lens ◽  
Rat Tissues ◽  
Thin Sections ◽  
Reconstruction Methods ◽  
Scanning Electron

Our current understanding of mitochondrial ultrastructure has been derived primarily from thin sections using transmission electron microscopy (TEM). This information has been extrapolated into three dimensions by artist's impressions (1) or serial sectioning techniques in combination with computer processing (2). The resolution of serial reconstruction methods is limited by section thickness whereas artist's impressions have obvious disadvantages.In contrast, the new techniques of HRSEM used in this study (3) offer the opportunity to view simultaneously both the internal and external structure of mitochondria directly in three dimensions and in detail.The tridimensional ultrastructure of mitochondria from rat hepatocytes, retinal (retinal pigment epithelium), renal (proximal convoluted tubule) and adrenal cortex cells were studied by HRSEM. The specimens were prepared by aldehyde-osmium fixation in combination with freeze cleavage followed by partial extraction of cytosol with a weak solution of osmium tetroxide (4). The specimens were examined with a Hitachi S-570 scanning electron microscope, resolution better than 30 nm, where the secondary electron detector is located in the column directly above the specimen inserted within the objective lens.

Inelastic Electron Scattering from Valence Electrons in Aluminum

1976 ◽  
Vol 34 ◽  
pp. 462-463
Author(s):  
P. E. Batson ◽  
C. H. Chen ◽  
J. Silcox
Keyword(s):  
Electron Scattering ◽  
Single Scattering ◽  
Three Dimensions ◽  
Inelastic Electron ◽  
Weak Beam ◽  
Scattering Spectrum ◽  
Valence Electrons ◽  
Diffraction Patterns ◽  
Electronic Scattering

We wish to report in this paper measurements of the inelastic scattering component due to the collective excitations (plasmons) and single particlehole excitations of the valence electrons in Al. Such scattering contributes to the diffuse electronic scattering seen in electron diffraction patterns and has recently been considered of significance in weak-beam images (see Gai and Howie) . A major problem in the determination of such scattering is the proper correction for multiple scattering. We outline here a procedure which we believe suitably deals with such problems and report the observed single scattering spectrum.In principle, one can use the procedure of Misell and Jones—suitably generalized to three dimensions (qx, qy and #x2206;E)--to derive single scattering profiles. However, such a computation becomes prohibitively large if applied in a brute force fashion since the quasi-elastic scattering (and associated multiple electronic scattering) extends to much larger angles than the multiple electronic scattering on its own.

Advantages of Complementary Stereo Images as Viewed with the Low-Temperature Field-Emission SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1314-1315
Author(s):  
William P. Wergin ◽  
Eric F. Erbe
Keyword(s):  
Fold Increase ◽  
Horizontal Displacement ◽  
Three Dimensions ◽  
Stereo Image ◽  
Stereo Pair ◽  
Sem Micrograph ◽  
Left And Right ◽  
The Common ◽  
The Brain ◽  
Pair Analysis

The eye-brain complex allows those of us with normal vision to perceive and evaluate our surroundings in three-dimensions (3-D). The principle factor that makes this possible is parallax - the horizontal displacement of objects that results from the independent views that the left and right eyes detect and simultaneously transmit to the brain for superimposition. The common SEM micrograph is a 2-D representation of a 3-D specimen. Depriving the brain of the 3-D view can lead to erroneous conclusions about the relative sizes, positions and convergence of structures within a specimen. In addition, Walter has suggested that the stereo image contains information equivalent to a two-fold increase in magnification over that found in a 2-D image. Because of these factors, stereo pair analysis should be routinely employed when studying specimens.Imaging complementary faces of a fractured specimen is a second method by which the topography of a specimen can be more accurately evaluated.

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