101,911 research outputs found
Improved measurement of depth perception
Electromechanical system for Howard-Dolman device was developed. System is used for human depth perception measurements without tactual stimuli
AVIRIS scan drive design and performance
The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) images the ground with an instantaneous field of view (IFOV) of 1 mrad. The IFOV is scanned 30 deg from left to right to provide the cross-track dimension of the image, while the aircraft's motion provides the along-track dimension. The scanning frequency is 12 Hz, with a scan efficiency of 70 percent. The scan mirror has an effective diameter of 5.7 in, and its positional accuracy is a small fraction of a milliradian of the nominal position-time profile. Described are the design and performance of the scan drive mechanism. Tradeoffs among various approaches are discussed, and the reasons given for the selection of the cam drive
Field Studies of Sedimentary Sequences in Eastern Hurd Peninsula Central Livingston Island, South Shetland Islands
Analysis of Linsker's simulations of Hebbian rules
Linsker has reported the development of center-surround receptive fields and oriented receptive fields in simulations of a Hebb-type equation in a linear network. The dynamics of the learning rule are analyzed in terms of the eigenvectors of the covariance matrix of cell activities. Analytic and computational results for Linsker's covariance matrices, and some general theorems, lead to an explanation of the emergence of center-surround and certain oriented structures. We estimate criteria for the parameter regime in which center-surround structures emerge
Polarization switching and induced birefringence in InGaAsP multiple quantum wells at 1.5 mu m
We analyze the 1.5mum wavelength operation of a room temperature polarization switch based on electron spin dynamics in InGaAsP multiple quantum wells. An unexpected difference in response for left and right circularly polarized pump light in pump-probe measurements was discovered and determined to be caused by an excess carrier induced birefringence. Transient polarization rotation and ellipticity were measured as a function of time delay. (C) 2002 American Institute of Physics.</p
<theoretical studies on the relationships be- tween the thermionic work function of refrac- tory intermetallic compounds and their electronic and crystal structures< progress report, 1 jan. - 30 jun. 1965
Thermionic work function of refractory intermetallic compounds and their electronic and crystal structure
Teetered, tip-controlled rotor: Preliminary test results from Mod-0 100-kW experimental wind turbine
Results of tests conducted using the MOD-0 100 kW experimental wind turbine are evaluated. The teetered rotor significantly decreased loads on the yaw drive mechanism and reduced blade cyclic flapwise bending moments by 25 percent at the 20 percent span location when compared to the rigid hub rotor. The teetered hub performed well, but impacted the teeter stops on occasion as wind speed and/or direction varied rapidly. The tip-controlled rotor performed satisfactorily with some expected loss of control when compared to the full span pitchable blade. The performance results indicate that a review of techniques used to calculate rotor power is in order
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