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Institution

Raytheon

CompanyWaltham, Massachusetts, United States
About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.
Topics: Signal, Antenna (radio), Radar, Turbine, Amplifier


Papers
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Journal ArticleDOI
TL;DR: In this article, the authors derived trends in upper thermospheric density from the historical orbital elements of 27 long-lived, near-Earth space objects and examined several possible sources of error in their results and concluded that none of them can individually account for the observed trends.
Abstract: [1] We derive secular trends in upper thermospheric density from the historical orbital elements of 27 long-lived, near-Earth space objects. The results cover all levels of solar activity during the period 1996–2001, and each object indicates a long-term decrease of total mass density. The observed trends increase with increasing height from 200–700 km and are largest for solar minimum conditions; average values range from −2% to −5% per decade. The trends are largely independent of geomagnetic activity, local time, latitude, and season. We examine several possible sources of error in our results and conclude that none of them can individually account for the observed trends. The trends that we obtain are qualitatively, and in some cases quantitatively, consistent with available theoretical predictions of density decreases associated with the cooling effect of increased greenhouse gas concentrations.

159 citations

Journal ArticleDOI
TL;DR: In this paper, the fatigue behavior of ferroelectric PZT capacitors with Ru and RuOx electrodes was studied, and the initial polarization was lower, but after fatiguing the polarization was comparable to or larger than that for Pt electrodes.
Abstract: The fatigue behavior of ferroelectric PZT capacitors with Ru and RuOx electrodes was studied. These capacitors show no sign of fatigue out to 1 X 1011 cycles, in sharp contrast to the degradation typically observed with Pt electrodes. Compared to Pt electrodes, the initial polarization was lower, but after fatiguing the polarization was comparable to or larger than that for Pt electrodes. Differences in polarization in response to switching and nonswitching pulses greater than 10 μC/cm2 were observed at 1 X 1011 cycles.

158 citations

Journal ArticleDOI
TL;DR: In this article, a Si/Si 0.5Ge0.5/Si heterostructure was used to grow tunneling diodes using low temperature molecular beam epitaxy, which utilized both a central intrinsic spacer and injected injectors.
Abstract: Resonant interband tunneling diodes on silicon substrates are demonstrated using a Si/Si0.5Ge0.5/Si heterostructure grown by low temperature molecular beam epitaxy which utilized both a central intrinsic spacer and δ-doped injectors. A low substrate temperature of 370 °C was used during growth to ensure a high level of dopant incorporation. A B δ-doping spike lowered the barrier for holes to populate the quantum well at the valence band discontinuity, and an Sb δ-doping reduces the doping requirement of the n-type bulk Si by producing a deep n+ well. Samples studied from the as-grown wafers showed no evidence of negative differential resistance (NDR). The effect of postgrowth rapid thermal annealing temperature was studied on tunnel diode properties. Samples which underwent heat treatment at 700 and 800 °C for 1 min, in contrast, exhibited NDR behavior. The peak-to-valley current ratio (PVCR) and peak current density of the tunnel diodes were found to depend strongly on δ-doping placement and on the annea...

158 citations

Patent
15 May 1997
TL;DR: In this paper, a distributed biometric identification system and architecture for rapidly identifying individuals using fingerprint and photographic data is presented, which includes a centralized server coupled to a plurality of distributed client workstations by way of a wide area telecommunications network.
Abstract: A distributed biometric identification system and architecture for rapidly identifying individuals using fingerprint and photographic data. The present architecture includes a centralized server coupled to a plurality of distributed client workstations by way of a wide area telecommunications network. The server and client workstations each contain subsystems that cooperate to provide personnel identification services to users of the system. The distributed biometric identification system is designed to rapidly identify personnel based on the use of biometric (i.e., fingerprint or photograph) or other unique identification data. The system is an integrated, front-end automated fingerprint and photographic identification tool that supports comprehensive application processing and administrative systems, such as those of the INS and other government agencies.

158 citations

Patent
Dinyar Sepai1, Kevin R Daly1, Brian L Whalen1, Khanh Hong1, George B Jones1 
24 Jun 1994
TL;DR: In this paper, an automated electronic module inspection system consisting of two video cameras is presented, where a positioning table aligns a module-under-test with the optical axis of each camera thereby enabling the same field-of-view to be observed under different lighting conditions.
Abstract: An automated electronic module inspection system having illumination sources that produce digitized gray scale images that are then analyzed by a computer. The inspection system illuminates the module including solder joints, components and printed circuit board using a sequence of illumination that produce visual images which are used to identify defects. The inspection system inspects for all defects as specified in MIL-STD-2000A (Section 4.4) by using both surface reflectance properties as well as topological properties of objects. The system comprises two video cameras. A positioning table aligns a module-under-test with the optical axis of each camera thereby enabling the same field-of-view to be observed under different lighting conditions. A dark field illumination associated with a first camera preferentially illuminates non-flat surfaces, but not vertical surfaces. A bright field illumination associated with a second camera preferentially illuminates relatively flat surfaces. The flat-surface illumination light source is collimated with the optical axis of the camera using a conventional partially reflecting angled mirror that reflects the light along the camera's optical axis onto a circuit board of the module. The angled surfaces are illuminated using four ring-lights concentrically aligned with the optical axis of the second camera. The images observed by the camera are then analyzed by inspection programs for discrepancies between image model attributes and the images, and such programs provide compensation for nonuniformities of the light sources and cameras and compensation of shadows resulting from the dark field illumination light source.

158 citations


Authors

Showing all 15293 results

NameH-indexPapersCitations
Peter J. Kahrilas10958646064
Edward J. Wollack104732102070
Duong Nguyen9867447332
Miroslav Krstic9595542886
Steven L. Suib8986234189
Gabriel M. Rebeiz8780632443
Charles W. Engelbracht8321028137
Paul A. Grayburn7739726880
Eric J. Huang7220122172
Thomas F. Eck7215032965
David M. Margolis7022717314
David W. T. Griffith6528814232
Gerhard Klimeck6568518447
Nickolay A. Krotkov6321911250
Olaf Stüve6329014268
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20232
20228
2021265
2020655
2019579
2018457