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Displaying 43226 - 43250 of 73778

Nonresonant Effects in One- and Two-Photon Transitions

June 1, 2002
Author(s)
U Jentschura, Peter J. Mohr
We investigate nonresonant contributions to Rayleigh scattering cross sections in atomic transitions. The problematic nonresonant contributions set a limit to the accuracy to which atomic spectra determine energy levels. Specifically, we show that off

On Differential Thermal Analyzer Curves for the Melting and Freezing of Alloys

June 1, 2002
Author(s)
William J. Boettinger, Ursula R. Kattner
A model for the response of differential thermal analysis measurement techniques to melting and freezing is explored. The model, which uses a system of ordinary differential equations, predicts sample, sample cup and thermocouple temperature histories

Phase-Coherent Synthesis of Optical Frequencies and Waveforms

June 1, 2002
Author(s)
Jun Ye, Steven T. Cundiff, S M. Foreman, T M. Fortier, John L. Hall, K W. Holman, D J. Jones, J D. Jost, H C. Kapteyn, K A. Leeuwen, L -. Ma, M M. Murnane, J L. Peng, R K. Shelton
Precision phase control of an ultrawide-bandwidth optical-frequency comb has produced remarkable and unexpected progress in both areas of optical-frequency metrology and ultrafast optics. A frequency comb (with 100 MHz spacing) spanning an entire optical

PMD Measurement Techniques - Avoiding Measurement Pitfalls

June 1, 2002
Author(s)
Paul A. Williams
Polarization-mode dispersion (PMD) is an interesting phenomenon. Unfortunately, interesting usually means complicated, and that is definitely the case with PMD. These complications can be troublesome when attempting to measure PMD. This presentation has

Polymer Composites with High Dielectric Constant

June 1, 2002
Author(s)
C. K. Chiang, R Popielarz
A very high dielectric constant polymer composite film system is presented. The new polymer composite film uses cyanoresin polymer filled with ferroelectric ceramics, such as BaTiO 3 powder. While the dielectric constant of the cyanoresin polymer at 1 kHz

Proceedings of the 12th Halon Options Technical Working Conference

June 1, 2002
Author(s)
Richard G. Gann
This proceedings contains the papers from the 12th Halon Options Technical Working Conference. The topics covered include: results from the DoD Next Generation Fire Suppression Technology Program, total flood applications, passive fire protection

Statistical Uncertainty Analysis of CCEM-K2 Comparisions of Resistance Standards

June 1, 2002
Author(s)
Nien F. Zhang, N Sedransk, Dean G. Jarrett
Details of the statistical uncertainty analysis applied to key comparison CCEM-K2 are reported. Formulas were derived to determine the uncertainty of the combined difference between the measurements of multiple artifacts by an NMI and the corresponding

Statistical Uncertainty Analysis of CCEM-K2 Comparisons of Resistance Standards

June 1, 2002
Author(s)
Nien F. Zhang, N Sedransk, Dean G. Jarrett
Details of the statistical uncertainty analysis applied to key comparison CCEM-K2 are reported. Formulas were derived to determine the uncertainty of the combined difference between the measurements of multiple artifacts by an NMI and the corresponding

Structural Reliability Estimates and Database-Assisted Design for Wind

June 1, 2002
Author(s)
F Minciarelli, Fahim H. Sadek, Emil Simiu, Mircea Grigoriu
We propose a probabilistic methodology for developing improved estimates of extreme wind effects and load factors in standard provisions for wind loads. We obtained the following results: (1) the discrepancy between current estimates of safety indices for

Structural Study of Li 1+x-y Nb 1-x-3y Ti x+4y O 3 Solid Solutions

June 1, 2002
Author(s)
L Farber, Igor Levin, A Borisevich, I E. Grey, Robert S. Roth, P K. Davies
The structures of Lil+x-yNbl-,-3yTix+4yO3 solid solutions within the so-called M-phase field in the Li2O-Nb2O5-TiO2system were investigated using HRTEM and single crystal X-ray diffraction. The results demonstrated the phasefield is comprised of a

Structure and Properties of Silica Nanoclusters at High Temperatures

June 1, 2002
Author(s)
I V. Schweigert, K E. Lehtinen, Michael J. Carrier, Michael R. Zachariah
The properties of silica clusters at temperatures from 1500 to 2800 K are investigated using classical molecular dynamics simulations for particles containing up to 1152 atoms. We found that atoms in the cluster were arranged in a shell-like structure at

The Magic of Cryogenics

June 1, 2002
Author(s)
D P. Vigliotti, J B. Alcorn, B P. Marsh, N A. Neumeyer
The purpose of this presentation is to introduce teachers to a demonstration that exposes K-12 students to a variety of scientific areas through experiments using liquid nitrogen. This presentation demonstrates how changing the temperature of materials

The NIST Microforce Realization and Measurement Project

June 1, 2002
Author(s)
David B. Newell, Jon R. Pratt, John A. Kramar, Douglas T. Smith, Edwin R. Williams
The National Institute of Standards and Technology (NIST) has launched a five-year Microforce Realization and Measurement project focusing on the development of an instrument and laboratory capable of realizing and measuring the SI unit of force below

The NIST Microforce Realization and Measurement Project

June 1, 2002
Author(s)
David B. Newell, Jon R. Pratt, John A. Kramar, Douglas T. Smith, Edwin R. Williams
The National Institute of Standards and Technology (NIST) has launched a five-year Micro-force Realization and Measurement project focusing on the development of an instrument and laboratory capable of realizing and measuring the SI unit of force below
Displaying 43226 - 43250 of 73778
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