1,642 research outputs found
Proton-produced defects in n-type silicon
Defect energy levels and concentrations for proton irradiated, n-type silicon single crystal
Pyroelectric detector arrays
A pyroelectric detector array and the method for using it are described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching strips of indium are formed around the holes to make contact with the backside electrodes and form the output terminals for individual detectors. A pyroelectric detector strip with front and back electrodes, respectively, is mounted over the strips. Biasing resistors are formed on the surface of the silicon dioxide layer and connected to the strips. A metallized pad formed on the surface of layer is connected to each of the biasing resistors and to the film to provide the ground for the pyroelectric detector array
Two-electron bond-orbital model, 1
Harrison's one-electron bond-orbital model of tetrahedrally coordinated solids was generalized to a two-electron model, using an extension of the method of Falicov and Harris for treating the hydrogen molecule. The six eigenvalues and eigenstates of the two-electron anion-cation Hamiltonian entering this theory can be found exactly general. The two-electron formalism is shown to provide a useful basis for calculating both non-magnetic and magnetic properties of semiconductors in perturbation theory. As an example of the former, expressions for the electric susceptibility and the dielectric constant were calculated. As an example of the latter, new expressions for the nuclear exchanges and pseudo-dipolar coefficients were calculated. A simple theoretical relationship between the dielectric constant and the exchange coefficient was also found in the limit of no correlation. These expressions were quantitatively evaluated in the limit of no correlation for twenty semiconductors
Magnetometer with miniature transducer and automatic transducer scanning apparatus
Magnetometer is simple to operate and has fast response. Transducer is rugged and flat and can measure magnetic fields as close as 0.08 mm from any relatively flat surface. Magnetometer has active region of approximately 0.64 by 0.76 mm and is capable of good spatial resolution of magnetic fields as low as 0.02 Oe (1.6 A/m)
Precursor Space Station Freedom experiments
The NASA Office of Aeronautics and Space Technology uses the In-Space Technology Experiments Program (IN-STEP) as the primary management vehicle to pursue innovative and potentially high payoff space technology experiments. The purpose of this presentation is to provide an overview of the IN-STEP approach in developing precursor Space Station experiments; identify those experiments now in the program; review the key points of the IN-STEP 1992 Announcement of Opportunity; and describe the OAST in-space technology experiments development process
New angles on D-branes
A low-energy background field solution is presented which describes several
D-membranes oriented at angles with respect to one another. The mass and charge
densities for this configuration are computed and found to saturate the BPS
bound, implying the preservation of one-quarter of the supersymmetries.
T-duality is exploited to construct new solutions with nontrivial angles from
the basic one.Comment: Latex, 12 pages, still no figures, references update
Macroscopic and Microscopic Entropy of Near-Extremal Spinning Black Holes
A seven parameter family of five-dimensional black hole solutions depending
on mass, two angular momenta, three charges and the asymptotic value of a
scalar field is constructed. The entropy is computed as a function of these
parameters both from the Bekenstein-Hawking formula and from the degeneracies
of the corresponding D-brane states in string theory. The expressions agree at
and to leading order away from extremality.Comment: 7 pages, harvma
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