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Displaying 49901 - 49925 of 73832

Far-Field Antenna Patterns Determined from Infrared Holograms

July 1, 1999
Author(s)
Carl F. Stubenrauch, J. D. Norgard, J. E. Will, Katherine MacReynolds
In this paper, we describe a technique based on optical holography which allows determination of the amplitude and phase of an unknown antenna on a near-field plane from amplitude-only measurements.

Flat Panel Display Metrology -- Less than Meets the Eye

July 1, 1999
Author(s)
Edward F. Kelley
Accurate measurement of electronic displays has become important in recent years owing to the advances in flat panel display technologies. A well-defined language is needed to specify, evaluate, and compare display technologies and their suitability to

Image Sharpness Measurement in Scanning Electron Microscope - Part III

July 1, 1999
Author(s)
Samuel N. Jones, Robert D. Larrabee, Michael T. Postek, Andras Vladar, Nien F. Zhang
Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. Testing and proving that the instrument is performing at a satisfactory level of sharpness is an

Kinetic, Stereochemical, and Structural Effects of Mutations of the Active Site Arginine Residues in 4-Oxalocrotonate Tautomerase

July 1, 1999
Author(s)
T K. Harris, R M. Czerwinski, W H. Johnson, P M. Legler, C Abeygunawardana, M A. Massiah, J T. Stivers, C P. Whitman, A S. Mildvan
Three arginine residues (Arg-11, Arg-39, Arg-61) are found at the active site of 4-oxalocrotonate tautomerase in the X-ray structure of the affinity-labeled enzyme [Taylor, A. B., Czerwinski, R. M., Johnson Jr., R. M., Whitman, C. P., and Hackert, M. L.

Large Scale Simulations of Single and Multi-Component Flow in Porous Media

July 1, 1999
Author(s)
Nicos Martys, John G. Hagedorn, D S. Goujon, J E. Devaney
We examine the utility of the lattice Boltzmann method for modeling fluid flow in large microstructures. First, results of permeability calculations are compared to predicted values for several idealized geometries. Large scale simulations of fluid flow

Lattice Boltzmann Simulations of Single and Multi-Component Flow in Porous Media

July 1, 1999
Author(s)
Nicos Martys, John G. Hagedorn, J E. Devaney
We examine the utility of the lattice Boltzmann method for modeling fluid flow in porous media. First the lattice Boltzmann method is validated for the case of single component flow in several idealized flow geometries. Large scale simulations of fluid

Measurement of the Rheological Properties of Cement Paste: A New Approach

July 1, 1999
Author(s)
Chiara F. Ferraris
This paper presents a new approach for predicting the rheological properties of concrete from rheological measurements on cement paste and from concrete composition. This approach requires measurement of the cement paste rheology under the same conditions

Methods to Remove Distortion Artifacts in Scanned Projections

July 1, 1999
Author(s)
A R. Kalukin, Zachary H. Levine, Charles S. Tarrio, S P. Frigo, I McNulty, S S. Wang, C C. Retsch, M Kuhn, B Winn
Atrifacts induced by distortions which sometimes occur in two-dimensional projection images can appear in the resulting tomographic reconstructions. We describe a procedure for analyzing, correcting and removing experimental atrifacts, and hence reducing

Microscopic Image Analysis of Defect Areas in Optical Disks

July 1, 1999
Author(s)
P L'Hostis, Frederick R. Byers, Fernando L. Podio, Xiao Tang
This paper presents techniques developed in the Information Technology Laboratory of the US National Institute of Standards and Technology (NIST/ITL) for enabling microscopic image analysis of optical data storage media such as optical discs. These non

Modern Wavelength Standards in the Ultraviolet and Vacuum Ultraviolet

July 1, 1999
Author(s)
Joseph Reader, Craig J. Sansonetti
In recent work at the National Institute of Standards and Technology the Atomic Spectroscopy Group has characterized several sources of wavelength standards useful for remote sensing applications. At low resolution, mercury pencil-type lamps are convenient

Multidetector Hemispherical Polarized Optical Scattering Instrument

July 1, 1999
Author(s)
Thomas A. Germer
A multidetector optical scattering instrument is described and characterized. The instrument has twenty-eight detectors surrounding and substantially covering the scattering hemisphere. Each detector contains a polarizer so that each is only sensitive to p

Negative Ion-Neutral Reactions in Townsend Discharges

July 1, 1999
Author(s)
James K. Olthoff, MVVS. Rao
Relative intensities and translational ion-flux energy distributions are presented for negative ions sampled from Townsend discharges in O 2, SF 6, and CF 4 for a high range of density reduced electric fields greater than 2 W 10 -18 V m 2 (> 2 kTd). These

On-Line Monitoring and Fault Detection of Control System Performance

July 1, 1999
Author(s)
J E. Seem, J House, R H. Monroe
Modern energy management and control systems have alarm and trend features that allow building operators to monitor and troubleshoot building systems. The alarm feature can provide nearly immediate feedback when, for instance, a sensor value is ourside
Displaying 49901 - 49925 of 73832
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