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Displaying 47901 - 47925 of 74209

In situ Metrology During the Growth of Compound Semiconductors by Molecular Beam Epitaxy

February 9, 2000
Author(s)
Donald A. Gajewski, Jonathan E. Guyer, Nhan Van Nguyen, Joseph G. Pellegrino
In this poster, we present the optical response of thin film compound semiconductors measured using in situ spectroscopic ellipsometry (SE), at growth temperatures ((180 to 600) 0C), during the growth by molecular beam epitaxy (MBE). We will focus on in

X-Ray Topography Study of Surface Damage in Single-Crystal Sapphire

February 9, 2000
Author(s)
David R. Black, Robert S. Polvani, Kate Medicus, H E. Burdette
X-ray diffraction topography was used to investigate the relationship between sub-surface damage, near-surface microstructure, and fracture strength in a series of sapphire modulus of rupture (MOR) bars which had been fabricated to proof test fabrication

On the Bifurcation From Continuous to Segmented Chip Formation in Metal Cutting

February 6, 2000
Author(s)
Timothy J. Burns, Matthew A. Davies, Christopher J. Evans
We describe a new approach to modeling chip formation in orthogonal machining. Metal cutting is interpreted as a nonlinear dynamical process with thermomechanical feedback, which is similar in many ways to an open chemical reactor. As the cutting speed is

A Differentiated Optical Services Model for WDM Networks

February 1, 2000
Author(s)
Nada T. Golmie, T D. Ndousse, David H. Su
This paper addresses the issues of guaranteed and scalable end-to-end QoS in Metropolitan DWDM networks serving as transit networks for IP access networks. DWDM offering few wavelengths have in the past been deployed in the backbone network to upgrade

A Frequency Stabilized Laser Array for Use in Displacement Metrology

February 1, 2000
Author(s)
J Pedulla, R Deslattes, John R. Lawall
We have developed a frequency stabilized laser system to supply light to measure atomic-scale displacements of a stage moved in real time. Each laser in the array provides enough power ({approximately equal to} 1 mW) for four Michelson interferometers

An Introduction to Evaluating Biometric Systems

February 1, 2000
Author(s)
P J. Phillips, Alvin F. Martin, Charles L. Wilson, Mark A. Przybocki
How and where biometric systems are deployed will depend on their performance. Knowing what to ask and how to decipher the answers can help you evaluate the performance of these emerging technologies. On the basis of media hype alone, you might conclude

An Ultracold Neutral Plasma Created by Photoionizing Laser-Cooled Xenon

February 1, 2000
Author(s)
T C. Killian, S Kulin, S L. Rolston
We create an ultracold neutral plasma by photoionization of laser-cooled xenon atoms. The charge carrier density is as high as 2 x10^{9} cm^{-3}, and the temperatures of electrons and ions are as low as 100 mK and 10 uK, respectively. Such low temperatures

Atomic Force Microscopy of Hybrid Bilayer Membranes

February 1, 2000
Author(s)
John T. Woodward IV
Hybrid bilayer membranes (HBM) are synthetic membrane mimics designed to form a biomimetic surface. The basic HBM system consists of a lipid monolayer adsorbed to an alkanethiol self-assembled monolayer. More advanced versionshave used different thiolates

Atomic Weights and Isotopic Compositions (Version 2.0)

February 1, 2000
Author(s)
J S. Coursey, Robert A. Dragoset
The atomic weights are available for elements 1 through 111, and isotopic compositions or abundances are given when appropriate. The atomic weights data were published by T. B. Coplen in Atomic Weights of the Elements 1995, and the isotopic compositions

Capillary X-Ray Microfluorescence Instrument

February 1, 2000
Author(s)
J R. Swider
Although many techniques for microanalysis exist, few are totally nondestructive, easy to maintain, or portable. Techniques such as Electron Probe Microanalysis (EPMA) deliver sub-micrometer beams, but are destructive in sample preparation and in analysis

Ceramic Coatings Metrology Workshop Report

February 1, 2000
Author(s)
S J. Dapkunas
The Ceramic Coatings Metrology Workshop was held at NIST to identify the measurement needs of the various industries that manufacture and use ceramic coatings. The industrial perspectives were complemented by reviews of the scientific issues that require

Chemical Science and Technology Laboratory 1999 Technical Activities Report

February 1, 2000
Author(s)
Hratch G. Semerjian, W Koch
This report summarizes the research and services provided by the Chemical Science and Technology Laboratory of the National Institute of Standards and Technology for Fiscal Year 1999. The report includes: a general overview of the laboratory's activities
Displaying 47901 - 47925 of 74209