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Displaying 36901 - 36925 of 74377

Impulsive Loading of Cellular Media in Sandwich Construction

July 31, 2005
Author(s)
Joseph A. Main, George A. Gazonas
Motivated by recent efforts to mitigate blast loading using energy absorbing materials, this paper investigates the uniaxial crushing of cellular media in sandwich construction under impulsive pressure loading. The cellular core material is modeled using a

Uncertainties in Aspheric Profile Measurements with the Geometry Measuring Machine at NIST

July 31, 2005
Author(s)
Ulf Griesmann, Nadia Machkour-Deshayes, Byoung C. Kim, Quandou (. Wang, Lahsen Assoufid
The Geometry Measuring Machine (GEMM) of the National Institute of Standards and Technology (NIST) is a profilometer for free-form surfaces. A profile is reconstructed from local curvature of a test part surface, measured at several locations along a line

Coupled Fire Dynamics and Thermal Response ofComplex Building Structures

July 30, 2005
Author(s)
Kuldeep R. Prasad, Howard R. Baum
Simulation of the effects of severe fires on the structural integrity ofbuildings requires a close coupling between the gas phase energy release andtransport phenomena and the stress analysis in the load bearing materials.The connection between the two is

Critical-Current Measurements on ITER Nb3Sn Strands: Effect of Temperature

July 29, 2005
Author(s)
Loren F. Goodrich, Najib Cheggour, John (Jack) W. Ekin, Theodore C. Stauffer
Transport critical-current (II c) measurements were made on commercial multifilamentary Nb 3Sn strands at temperatures (T) from 4 to 17 K and magnetic fields (H) from 0 to 14 T. Samples investigated were taken from the stage 1 pre-production strand for the

Spectroscopy Using Quantum Logic

July 29, 2005
Author(s)
Piet Schmidt, Till P. Rosenband, C. Langer, Wayne M. Itano, James C. Bergquist, David J. Wineland
We have demonstrated experimentally a general technique for precision spectroscopy of atoms that lack suitable transitions for efficient laser cooling, internal state preparation, and detection. In our implementation with trapped atomic ions, an auxillary

Fiber Laser Frequency Combs and their Control

July 25, 2005
Author(s)
Nathan R. Newbury, Brian Washburn, William C. Swann, Jeffrey W. Nicholson, K Feder, Paul S. Westbrook
Fiber laser-based frequency combs can provide a comb of well-defined spectral lines across the near-infrared, including the telecommunication. We discuss these frequency combs with an emphasis on the mechanisms used to phase-lock the combs.

High resolution spectroscopy with a femtosecond laser frequency comb

July 25, 2005
Author(s)
Vladislav Gerginov, C E. Tanner, Scott A. Diddams, A Bartels, Leo W. Hollberg
The output of a mode-locked femtosecond-laser is usd for high resolution spectroscopy of Cs in an atomic beam. The laser is referenced directly to the stable RF signal from the NIST time-scale. By changing the laser's rate, the Cs D 1 and D 2 transitions

Optical frequency metrology using spectrally tailored continuum from a nonlinear fiber grating

July 25, 2005
Author(s)
Kyoungsik Kim, Brian R. Washburn, Christopher W. Oates, Leo W. Hollberg, Nathan R. Newbury, Scott A. Diddams, P. S. Westbrook, Jeffrey W. Nicholson, K Feder
We report the significant enhancement (-24 dB) of the optical beat note between a 657-nm CW laser and the tailored continuum generated with a nonlinear fiber Bragg grating. The same continuum is used to stabilize the offset frequency of a Cr:forsterite

Optical frequency metrology using spectrally tailored continuum from a nonlinear fiber grating

July 25, 2005
Author(s)
Kyoungsik Kim, Brian R. Washburn, C. W. Oates, Leo W. Hollberg, Nathan R. Newbury, Scott Diddams, Paul S. Westbrook, Jeffrey W. Nicholson, K Feder
We report the significant enhancement (24 dB) of the optical beat note between a 657-nm CW laser and the tailored continuum generated with a nonlinear fiber Bragg grating. The same continuum is used to stabilize the offset frequency of a Cr:forsterite

Optical Microwave Frequency Stability: Some Constraints

July 25, 2005
Author(s)
Leo W. Hollberg, Scott A. Diddams, A Bartels, John J. McFerran, Eugene N. Ivanov, G Wilpers, Christopher W. Oates
Optical frequency references achieve the best frequency stability of any oscillators by taking advantage of high Q = υ 0/{Δ}υ optical resonances. These systems are beginning to run into fundamental and technical limitations which are discussed.

Spectroscopy of a single Al + ion via coupling to Be +

July 25, 2005
Author(s)
Till P. Rosenband, Piet Schmidt, Jeroen Koelemeij, Wayne M. Itano, Yohei Kobayashi, Tara M. Fortier, Scott A. Diddams, James C. Bergquist, David J. Wineland
We perform precision spectroscopy on 27Al + with the aid of a 9Be + ion. Using sympathetic cooling and quantum state transfer, we efficiently interrogate the 1S 0 – 3P 1 and 1S 0 – 3P 0 transitions.

Laboratory X-Ray Imaging of High-Intensity Discharge Lamps

July 22, 2005
Author(s)
John J. Curry, B Lafitte
We describe a laboratory-scale system for x-ray absorption imaging of the Hg vapor distribution in high-intensity discharge plasmas. This system utilizes commercially-available equipment, including an x-ray tube source. We analyze the sensitivity of the

Measurement of the Quadrupole Moment in the Mercury Ion Optical Clock

July 21, 2005
Author(s)
Windell Oskay, Wayne M. Itano, James C. Bergquist
We report a measurement of the 199Hg + 5d 96 s 2 2 d5/2 electric quadrupole moment and discuss its implications for the accruacy of an optical clock based upon 2S 1/2(F=0)<-> 2 d5/2(F=2) transition at 282 nm.

Interferometric Thickness Calibration of 300mm Silicon Wafers

July 20, 2005
Author(s)
Quandou (. Wang, Ulf Griesmann, Robert S. Polvani
The Improved Infrared Interferometer (IR3) at the National Institute of Standards and Technology (NIST) is a phase-measuring interferometer, operating at a wavelength of 1550 nm, which is being developed for measuring the thickness and thickness variation

Direct Measurement of the Counterion Distribution Within Swollen Polyelectrolyte Films

July 19, 2005
Author(s)
Vivek M. Prabhu, B D. Vogt, Wen-Li Wu, Eric K. Lin, Jack F. Douglas, Sushil K. Satija, D L. Goldfarb, H Ito
The depth profile of the counterion concentration within thin polyelectrolyte films was measured in situ using contrast variant specular neutron reflectivity to characterize the initial swelling stage of the film dissolution.Wefind substantial counterion
Displaying 36901 - 36925 of 74377
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