48,456 research outputs found
Power density measurements in the near field of the DSS 13 26-meter antenna
Power density measurements were made at Deep Space Station (DSS) 13 in the near field of the 26-m antenna to determine if radio frequency (rf) fields generated by the 20-kW transmitters could be responsible for the failure of three solid state rf amplifiers. These amplifiers are used in the Search for Extraterrestrial Intelligence (SETI) Radio Spectrum Surveillance System, which is currently located at the site. Measurements were made independently for one transmitter at 7150 MHz, and both transmitters together. Measurement results are tabulated and compared with predicted power densities under the measurement conditions. The results agree with the predictions within a factor of two. The predictions appear to give worst case values. Measurements indicated that amplifier failures are not attributable to the transmitter
Radio frequency interference survey over the 1.0-10.4 GHz frequency range at the Goldstone-Venus Development Station
The results of a low sensitivity Radio Frequency Interference (RFI) survey carried out at the Venus Station of the Goldstone Communications Complex are reported. The data cover the spectral range from 1 GHz to 10.4 GHz with a 10-kHz instantaneous bandwidth. Frequency and power levels were observed using a sweep-frequency spectrum analyzer connected to a 1-m diameter antenna pointed at zenith. The survey was conducted from February 16, 1987 through February 24, 1987
Electrolytically regenerative hydrogen-oxygen fuel cell Patent
Electrolytically regenerative hydrogen-oxygen fuel cell
Observations of stratospheric source gas profiles during the Arctic winter
An international campaign was performed at ESRANGE rocket base, near Kiruna, Sweden (68 N) from January 4 to February 15 in order to investigate the Chemistry of Ozone in the Polar Stratosphere (CHEOPS). Within the framework of this campaign two sets of large stratospheric air samples were collected by means of a balloon borne cryogenic air sampler. The two balloons were launched on February 1, and February 10, 1988. At present the samples are analyzed in our laboratory for their contents of several long lived trace gases such as CH4, N2O, H2, CO2, CO and the major halocarbons CH3Cl, CFCl3, CF2Cl2, CCl4, CH3CCl3, and C2F3Cl3. The vertical profiles derived from these samples will be presented and compared with previous observations made in February 1987. The data will be discussed in view of the dynamical evolution of the Arctic polar vortex during this winter
A psychoanalytic concept illustrated: Will, must, may, can — revisiting the survival function of primitive omnipotence
The author explores the linear thread connecting the theory of Freud and Klein, in terms of the central significance of the duality of the life and death instinct and the capacity of the ego to tolerate contact with internal and external reality. Theoretical questions raised by later authors, informed by clinical work with children who have suffered deprivation and trauma in infancy, are then considered. Theoretical ideas are illustrated with reference to observational material of a little boy who suffered deprivation and trauma in infancy. He was first observed in the middle of his first year of life while he was living in foster care, and then later at the age of two years and three months, when he had been living with his adoptive parents for more than a year
Non-resonant Raman response of inhomogeneous structures in the electron doped Hubbard model
We calculate the non-resonant Raman response, the single particle spectra and
the charge-spin configuration for the electron doped Hubbard model using
unrestricted Hartree-Fock calculations. We discuss the similarities and
differences in the response of homogeneous versus inhomogeneous structures.
Metallic antiferromagnetism dominates in a large region of the phase
diagram but at high values of the on-site interaction and for intermediate
doping values, inhomogeneous configurations are found with lower energy. This
result is in contrast with the case of hole doped cuprates where
inhomogeneities are found already at very low doping. The inhomogeneities found
are in-phase stripes compatible with inelastic neutron scattering experiments.
They give an incoherent background in the Raman response. The signal
can show a quasiparticle-like component even when no Fermi surface is found in
the nodal direction.Comment: 8 pages, 10 figures, accepted for publication in Phys. Rev.
Tunneling Spectroscopy and Vortex Imaging in Boron-Doped Diamond
We present the first scanning tunneling spectroscopy study of
single-crystalline boron doped diamond. The measurements were performed below
100 mK with a low temperature scanning tunneling microscope. The tunneling
density of states displays a clear superconducting gap. The temperature
evolution of the order parameter follows the weak coupling BCS law with
. Vortex imaging at low magnetic field also
reveals localized states inside the vortex core that are unexpected for such a
dirty superconductor.Comment: 4 pages, 4 figures, replaced with revised versio
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