25,001 research outputs found
Fluorinated esters of polycarboxylic acids
Fluorine containing esters of polycarboxylic acids are discussed. The use of these esters as extreme temperature lubricants and base fluids for greases is investigated
Preparation of ordered poly /arylenesiloxane/ polymers
Preparation of ordered poly/arylenesiloxane/ polymer
Development of lubricating oils suitable for use with liquid oxidizers Quarterly progress report, 1 Jun. - 31 Aug. 1970
Investigating ester and alkyl compounds as lubricating oils for use with liquid oxidizer
Possible Lattice Distortions in the Hubbard Model for Graphene
The Hubbard model on the honeycomb lattice is a well known model for
graphene. Equally well known is the Peierls type of instability of the lattice
bond lengths. In the context of these two approximations we ask and answer the
question of the possible lattice distortions for graphene in zero magnetic
field. The answer is that in the thermodynamic limit only periodic,
reflection-symmetric distortions are allowed and these have at most six atoms
per unit cell as compared to two atoms for the undistorted lattice.Comment: 5 pages, 3 figure
Development of lubricating oils suitable for use with liquid oxidizers Final summary report, 4 Mar. 1968 - 4 Mar. 1969
Lubricating properties and impact stability of polyfluoroalcohol derivatives at low temperatur
A mixed MAP/MLSE receiver for convolutional coded signals transmitted over a fading channel
Copyright © 2002 IEEEThis paper addresses the problem of estimating a rapidly fading convolutionally coded signal such as might be found in a wireless telephony or data network. We model both the channel gain and the convolutionally coded signal as Markov processes and, thus, the noisy received signal as a hidden Markov process (HMP). Two now-classical methods for estimating finite-state hidden Markov processes are the Viterbi (1967) algorithm and the a posteriori probability (APP) filter. A hybrid recursive estimation procedure is derived whereby one hidden process (the encoder state in our application) is estimated using a Viterbi-type (i.e., sequence based) cost and the other (the fading process) using an APP-based cost such as maximum a posteriori probability. The paper presents the new algorithm as applied specifically to this problem but also formulates the problem in a more general setting. The algorithm is derived in this general setting using reference probability methods. Using simulations, performance of the optimal scheme is compared with a number of suboptimal techniques-decision-directed Kalman and HMP predictors and Kalman filter and HMP filter per-survivor processing techniquesLangford B. White and Robert J. Elliot
A study of the effect of space radiation on silicon integrated circuits, phase 3, volume 2 Final report, 10 Apr. 1967 - 9 Apr. 1968
Characterization plans for studying effect of space radiation on silicon integrated microcircuit
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
Synthesis and evaluation of new high polymers for coating applications annual summary report no. 1, 26 jun. 1964 - 25 jun. 1965
Synthesis of organic and semi-organic polymers useful as high temperature coating materia
A program to develop a high-energy density primary battery with a minimum of 200 watt hours per pound of total battery weight Fifth quarterly report, 1 Jul. - 30 Sep. 1965
High energy density primary battery development - electrochemical half-cell screening of anode- electrolyte combinations, cell discharge, and potential studie
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