86,672 research outputs found
Method of resolving clock synchronization error and means therefor Patent
Development of method for synchronizing clocks at several ground stations based on signals received from spacecraft or satellite
Phase-locked loop with sideband rejecting properties Patent
Phase locked loop with sideband rejecting properties in continuous wave tracking rada
Photon Orbital Angular Momentum in Astrophysics
Astronomical observations of the orbital angular momentum of photons, a
property of electromagnetic radiation that has come to the fore in recent
years, have apparently never been attempted. Here, I show that measurements of
this property of photons have a number of astrophysical applications.Comment: 17 pages plus two figure
Fifteen-foot diameter modular space station Kennedy Space Center launch site support definition (space station program Phase B extension definition)
This document defines the facilities, equipment, and operational plans required to support the MSS Program at KSC. Included is an analysis of KSC operations, a definition of flow plans, facility utilization and modifications, test plans and concepts, activation, and tradeoff studies. Existing GSE and facilities that have a potential utilization are identified, and new items are defined where possible. The study concludes that the existing facilities are suitable for use in the space station program without major modification from the Saturn-Apollo configuration
Acoustic test of a model rotor and tail rotor: Results for the isolated rotors and combined configuration
Acoustic data from a model scale main rotor and tail rotor experiment in the NASA Langley 14 by 22 Foot Subsonic Tunnel are presented for the main rotor and trail rotor in isolation and for the two rotors operating together. Results for the isolated main rotor show the importance of the rotor flapping conditions on mid-frequency noise content. High levels of main rotor retreating side blade-vortex interaction noise are shown to radiate downstream of the model. The isolated tail rotor noise results show the dominance of harmonic noise in the thrusting direction. The occurrence of tail rotor broadband noise is seen by the broadening of the tail rotor harmonics and is attributed to fuselage wake turbulence. The combined main and tail rotor data are presented to show the dominance of each rotor's different noise sources at different directivity locations
Welding of commercial base plates is investigated
Investigation of aluminum alloy welds reveals that the combinations of metallic elements with hydrogen are not capable of producing weld porosity themselves, rather they tend to increase the amount of porosity only in the presence of arc contamination by water vapor
Arkansas Cotton Variety Test 2016
The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas
Observation of ferromagnetic resonance in strontium ruthenate (SrRuO3)
We report the observation of ferromagnetic resonance (FMR) in SrRuO3 using
the time-resolved magneto-optical Kerr effect. The FMR oscillations in the
time-domain appear in response to a sudden, optically induced change in the
direction of easy-axis anistropy. The high FMR frequency, 250 GHz, and large
Gilbert damping parameter, alpha ~ 1, are consistent with strong spin-orbit
coupling. We find that the parameters associated with the magnetization
dynamics, including alpha, have a non-monotonic temperature dependence,
suggestive of a link to the anomalous Hall effect.Comment: submitted to Phys. Rev. Let
Critical Phenomena Inside Global Monopoles
The gravitational collapse of a triplet scalar field is examined assuming a
hedgehog ansatz for the scalar field. Whereas the seminal work by Choptuik with
a single, strictly spherically symmetric scalar field found a discretely
self-similar (DSS) solution at criticality with echoing period ,
here a new DSS solution is found with period . This new critical
solution is also observed in the presence of a symmetry breaking potential as
well as within a global monopole. The triplet scalar field model contains
Choptuik's original model in a certain region of parameter space, and hence his
original DSS solution is also a solution. However, the choice of a hedgehog
ansatz appears to exclude the original DSS.Comment: 5 pages, 5 figure
Measurable quantum geometric phase from a rotating single spin
We demonstrate that the internal magnetic states of a single nitrogen-vacancy
defect, within a rotating diamond crystal, acquire geometric phases. The
geometric phase shift is manifest as a relative phase between components of a
superposition of magnetic substates. We demonstrate that under reasonable
experimental conditions a phase shift of up to four radians could be measured.
Such a measurement of the accumulation of a geometric phase, due to macroscopic
rotation, would be the first for a single atom-scale quantum system.Comment: 5 pages, 2 figures: Accepted for publication in Physical Review
Letter
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