Application of ray-path geometry modification to the design of a collimating structure for LEDs

2008 ◽  
Vol 281 (23) ◽  
pp. 5674-5682 ◽  
Author(s):  
A. Mandatori ◽  
A. Benedetti ◽  
C. Sibilia ◽  
M. Bertolotti
Keyword(s):  
Path Geometry ◽  
Ray Path

scholarly journals Dielectric Permittivity of Glacier Ice Measured In Situ by Radar Wide-Angle Reflection

1978 ◽  
Vol 21 (85) ◽  
pp. 315-329 ◽  
Author(s):  
Kenneth C. Jezek ◽  
John W. Clough ◽  
Charles R. Bentley ◽  
Sion Shabtaie
Keyword(s):  
Physical Phenomenon ◽  
Ice Core ◽  
Wide Angle ◽  
Ice Shelf ◽  
Ross Ice Shelf ◽  
Satisfactory Model ◽  
Glacier Ice ◽  
Path Geometry ◽  
Ray Path

AbstractValues of relative permittivity measured by the wide-angle reflection technique on the Ross ice Shelf show substantial variations between sites, from 3.09 to 2.89, with estimated errors of ±0.03. The largest values, closest to those normally measured in the laboratory, are found nearest to the grounded ice sheet; values decrease generally in the direction of thinner ice that has been longer on the ice shelf. We believe the variation reflects some real physical phenomenon in the ice shelf, either a true variation in the permittivity of the ice or a complication of the ray-path geometry, but are not able to offer a satisfactory model at present. We hope an explanation will be forthcoming when actual ice core samples from the deep shelf ice are available for examination.

scholarly journals Dielectric Permittivity of Glacier Ice Measured In Situ by Radar Wide-Angle Reflection

1978 ◽  
Vol 21 (85) ◽  
pp. 315-329 ◽  
Author(s):  
Kenneth C. Jezek ◽  
John W. Clough ◽  
Charles R. Bentley ◽  
Sion Shabtaie
Keyword(s):  
Physical Phenomenon ◽  
Ice Core ◽  
Wide Angle ◽  
Ice Shelf ◽  
Ross Ice Shelf ◽  
Satisfactory Model ◽  
Glacier Ice ◽  
Path Geometry ◽  
Ray Path

Abstract Values of relative permittivity measured by the wide-angle reflection technique on the Ross ice Shelf show substantial variations between sites, from 3.09 to 2.89, with estimated errors of ±0.03. The largest values, closest to those normally measured in the laboratory, are found nearest to the grounded ice sheet; values decrease generally in the direction of thinner ice that has been longer on the ice shelf. We believe the variation reflects some real physical phenomenon in the ice shelf, either a true variation in the permittivity of the ice or a complication of the ray-path geometry, but are not able to offer a satisfactory model at present. We hope an explanation will be forthcoming when actual ice core samples from the deep shelf ice are available for examination.

Application of ray-path geometry to the design of an optical cloaking structure

2008 ◽  
Vol 25 (10) ◽  
pp. 1580 ◽  
Author(s):  
A. Mandatori ◽  
A. Benedetti ◽  
C. Sibilia ◽  
M. Bertolotti
Keyword(s):  
Path Geometry ◽  
Ray Path

Transmission Scanning Electron Microscopy and Energy Analysis with the Siemens ELMISKOP 101

1972 ◽  
Vol 30 ◽  
pp. 450-451
Author(s):  
H. M. Thieringer
Keyword(s):  
Objective Lens ◽  
Transmission Microscopy ◽  
Image Recording ◽  
Mode Of Operation ◽  
Scanning Transmission ◽  
Electron Microscopes ◽  
And Performance ◽  
Convergent Beam ◽  
Ray Path ◽  
Beam Diffraction

It has repeatedly been show that with conventional electron microscopes very fine electron probes can be produced, therefore allowing various micro-techniques such as micro recording, X-ray microanalysis and convergent beam diffraction. In this paper the function and performance of an SIEMENS ELMISKOP 101 used as a scanning transmission microscope (STEM) is described. This mode of operation has some advantages over the conventional transmission microscopy (CTEM) especially for the observation of thick specimen, in spite of somewhat longer image recording times.Fig.1 shows schematically the ray path and the additional electronics of an ELMISKOP 101 working as a STEM. With a point-cathode, and using condensor I and the objective lens as a demagnifying system, an electron probe with a half-width ob about 25 Å and a typical current of 5.10-11 amp at 100 kV can be obtained in the back focal plane of the objective lens.

Elevation-angle based two-ray path loss model for Air-to-Ground wireless channels

2021 ◽  
pp. 100393
Author(s):  
N.H. Ranchagoda ◽  
K. Sithamparanathan ◽  
M. Ding ◽  
A. Al-Hourani ◽  
K.M. Gomez
Keyword(s):  
Wireless Channels ◽  
Elevation Angle ◽  
Path Loss ◽  
Loss Model ◽  
Path Loss Model ◽  
Ray Path

scholarly journals Simple and Exact Closed-Form Expression for Determination of a Penetrated Ray Path in a Ray Tracing

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Hyun Wook Moon ◽  
Woojoong Kim ◽  
Sewoong Kwon ◽  
Jaeheung Kim ◽  
Young Joong Yoon
Keyword(s):  
Closed Form ◽  
Approximate Method ◽  
Ray Tracing ◽  
Conventional Method ◽  
Closed Form Expression ◽  
Indoor Environments ◽  
Straight Line ◽  
Ray Path ◽  
Ray Tracing Simulation

A simple and exact closed-form equation to determine a penetrated ray path in a ray tracing is proposed for an accurate channel prediction in indoor environments. Whereas the penetrated ray path in a conventional ray tracing is treated as a straight line without refraction, the proposed method is able to consider refraction through the wall in the penetrated ray path. Hence, it improves the accuracy in ray tracing simulation. To verify the validation of the proposed method, the simulated results of conventional method, approximate method, and proposed method are compared with the measured results. The comparison shows that the proposed method is in better agreement with the measured results than the conventional method and approximate method, especially in high frequency bands.

Conserving the Coherence and Uniformity of Third-Generation Synchrotron Radiation Beams: the Case of ID19, a `Long' Beamline at the ESRF

1998 ◽  
Vol 5 (5) ◽  
pp. 1243-1249 ◽  
Author(s):  
José I. Espeso ◽  
Peter Cloetens ◽  
José Baruchel ◽  
Jürgen Härtwig ◽  
Trevor Mairs ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Phase Contrast ◽  
Angular Size ◽  
Third Generation ◽  
Optical Elements ◽  
X Ray ◽  
Front End ◽  
Ray Path ◽  
Radiation Beams

The lateral coherence length is of the order of 100 µm at the `long' (145 m) ID19 beamline of the ESRF, which is mainly devoted to imaging. Most of the optical elements located along the X-ray path can thus act as `phase objects', and lead to spurious contrast and/or to coherence degradation, which shows up as an enhanced effective angular size of the source. Both the spurious contrast and the coherence degradation are detrimental for the images (diffraction topographs, tomographs, phase-contrast images) produced at this beamline. The problems identified and the way they were solved during the commissioning of ID19 are reported. More particularly, the role of the protection foils located in the front end, the beryllium windows, the filters and the monochromator defects (scratches, dust, small vibrations) is discussed.

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