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Displaying 41351 - 41375 of 73970

Asymptotic Properties of Self-Energy Coefficients

April 1, 2003
Author(s)
U Jentschura, E O. LeBigot, Peter J. Mohr, Paul Indelicato, G Soff
We investigate the asymptotic properties of higher-order binding corrections to the one-loop self energy of excited states in atomic hydrogen. We evaluate the historically problematic A 60 coefficient for all P states with principal quantum numbers n {less

Calibrated Measurement of Optoelectronic Frequency Response

April 1, 2003
Author(s)
Paul D. Hale, Dylan Williams
We describe a straightforward method for accurately measuring the frequency response of optoelectronic devices. The method uses a calibrated optical reference receiver, a modulated optical source, and a calibrated electrical vector network analyzer.

CCEM-K2 Key Comparison of 10 Mohm and 1 Gohm Resistance Standards

April 1, 2003
Author(s)
Dean G. Jarrett, Ronald F. Dziuba
An international comparison of dc resistance at 10 Mohm and 1 Gohm was organized under the auspices of the Consultative Committee for Electricity and Magnetism (CCEM) and piloted by the National Institute of Standards and Technology (NIST) with 14 other

Characterization of an Ellipsoidal Radiometer

April 1, 2003
Author(s)
A V. Murthy, I Wetterlund, D P. DeWitt
An ellipsoidal radiometer, under development by Nils-Erik Gunners in close cooperation with the SP Swedish National Testing and Research Institute, has been characterized using, a 25 mm variable-temperature blackbodv as a radiant source. This radiometer is

Characterization of Binary Josephson Series Arrays of Different Types at BNM-LNE and Comparisons with Conventional SIS Arrays

April 1, 2003
Author(s)
Jean-Pierre Lo-Hive, Sophie Djordjevic, Phillippe Cancela, Francois P. Piquemal, Ralf Behr, Charles J. Burroughs, H. Seppa
Three 1-V binary Josephson arrays developed by the NIST, the PTB, and the VTT, and using, respectively, superconductor-normal metal-superconductor (SNS), superconductor-insulator-normal metal-insulator-superconductor (SINIS), and externally shunted

Characterization of Nanoporous Low-k Thin Films by Contrast Match SANS

April 1, 2003
Author(s)
R C. Hedden, Barry J. Bauer, Hae-Jeong Lee
Small-angle neutron scattering (SANS) contrast variation is used to characterize matrix properties and pore size in nanoporous low-k thin films. Using a vapor adsorption technique, SANS measurements are used to identify a contrast match solvent mixture

Choosing a Cantilever for In Situ Atomic Force Microscopy

April 1, 2003
Author(s)
John T. Woodward IV
This manuscript is a non-peer reviewed, invited tutorial for Microscopy Today. It describes the issues involved in choosing a cantilever for atomic force microscope (AFM) imaging under fluids. In situ AFM imaging is an increasingly popular technique for

Composite Substrate Research for Large-format HgCdTe IRFPAs

April 1, 2003
Author(s)
N. K. Dhar, Y Chen, P M. Brill, Paul M. Amirtharaj, S Velicu, P Boieriu, Anthony G. Birdwell
Research on silicon based composite substrates is being conducted at the Army Research Laboratory. These substrates can be used to deposit HgCdTe alloys to fabricate large-format infrared photodetector arrays. Traditionally, composite structures are

Direct Observation of Remanent Magnetic States in Epitaxial fcc Co Small Disks

April 1, 2003
Author(s)
C Vaz, L Lopez-Diaz, M Klaui, J Bland, T Monchesky, John Unguris, Z Cui
The magnetic nanostructure of epitaxial fcc Co/Cu(001) circular elements (1.7υm in diameter) has been imaged with scanning electron microscopy with polarization analysis. The disks are obtained by ultrahigh vacuum deposition of the metal films onto a

Electronic Properties of Quantum-Dot Molecules

April 1, 2003
Author(s)
W Jaskolski, M Zielinski, Garnett W. Bryant
We investigate the electronic structure of several double quantum dot systems: (I) hetero-dot artificial molecules built from two CdS chemically synthesized nanocrystals and (ii) two vertically stacked pyramidal self-organized InAs/GaAs quantum dots. The

Energy Dissipation Devices for Bridges with Steel Superstructures

April 1, 2003
Author(s)
Michael A. Riley
Recent earthquakes have clearly demonstrated the seismic vulnerability of bridges constructed with steel superstructures. The relative flexibility of these bridges, especially in the transverse direction, may result in overstressing or even failure of

Experimental Testing of Roof to Wall Connections in Wood Frame Houses

April 1, 2003
Author(s)
Michael A. Riley, Fahim H. Sadek
The majority of residential construction in the United States is wood-frame construction. These buildings perform well under gravity loads, but considerable damage has been observed in such structures after significant earthquakes and major hurricanes

Flame Retardant Mechanism of Silica - Effects of Molecular Weight of Resin

April 1, 2003
Author(s)
Takashi Kashiwagi, John R. Shields, Richard H. Harris Jr., Rick D. Davis
The effects of resin molecular weight, M w, on the flame retardant mechanism of silica were studied using two different molecular weights of PMMA, 122,000 g/mol and 996,000 g/mol and two silicas, fused silica with a low surface area and silica gel with a

Flux Pinning and Properties of Solid-Solution (Y,Nd) 1+x Ba 2-x Cu 3 O 7-d Superconductors

April 1, 2003
Author(s)
T J. Haugan, M E. Fowler, J C. Tolliver, Paul N. Barnes, Winnie K. Wong-Ng, Lawrence P. Cook
The effect of chemical composition variations on the flux pinning and physical properties of (Y,Nd)1+xBa2-xCu3O7-d superconductors was studied in powders processed by solid-state reaction and equilibrated in air at 910 C. An extended region of single-phase

High Resolution Infrared Studies of the N2, N4 Bands of 34 S 16 O 3 Including Both Intensity and Wavenumber Perturbations

April 1, 2003
Author(s)
J Barber, Tony Masiello, E T. Chrysostom, J Nibler, A G. Maki, A Weber, Thomas A. Blake, R L. Sams
The infrared spectrum of the Ņ 2, Ņ 4 bending mode region of 34S-substituted sulfur trioxide, 34S 16O 3, has been recorded at a resolution of 0.0025 cm -1. The Ņ 2 and Ņ 4 levels are coupled by a Coriolis interaction, yielding significant spectral shifts

High-accuracy determination of the dependence of the photoluminescence emission energy on alloy composition in Al x Ga 1-x As films

April 1, 2003
Author(s)
Larry Robins, J T. Armstrong, Ryna B. Marinenko, Albert J. Paul, John Pellegrino, Kristine A. Bertness
In an effort to improve the accuracy of photoluminescence (PL) measurements of the Al mole fraction (x) of Al xGa 1-xAs alloys, the PL peak emission energy, E PL,peak, was measured at room temperature for molecular-beam epitaxy-grown Al xGa 1-xAs films
Displaying 41351 - 41375 of 73970
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