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Displaying 36801 - 36825 of 74377

Dynamic Modeling and Vibration Analysis of a UHV Scanning Tunneling

August 17, 2005
Author(s)
Sumanth B. Chikkamaranahalli, R. R. Vallance, Bradley N. Damazo, Richard M. Silver, James D. Gilsinn
Techniques based on scanning probe microscopy (SPM) are used to fabricate surface structures with dimensions ranging from 10 - 100mm. These structures have been fabricated and imaged using a scanning tunneling microscope (STM), and the STM requires the tip

Linear and Generalized Linear Models for Analyzing Face Recognition Performance

August 17, 2005
Author(s)
J. R. Beveridge, Geof H. Givens, Bruce A. Draper, P. Jonathon Phillips
This paper introduces linear models (LM), generalized linear models (GLM), and generalized linear mixed models (GLMM) for analyzing performance of face recognition algorithms. These three statistical techniques are applied to analyzing the affect of

Microfluidic interfacial tensiometry

August 17, 2005
Author(s)
Steven D. Hudson, J Cabral, Kathryn L. Beers, W Goodrum, Eric J. Amis
A microfluidic approach to measure interfacial tension of immiscible fluids rapidly is reported. This method rests upon quantitative real-time analysis of two-phase flow and drop-shape dynamics. Drops of prescribed dimension and spacing are produced

Resonant microwave power absorption and relaxation of the energy levels of the molecular nanomagnet Fe 8 using superconducting quantum interference device-based magnetometry

August 15, 2005
Author(s)
Brant Cage, Stephen E. Russek, David Zipse, Micah North, Naresh S. Dalal
Energy levels and saturation of molecular nanomagnet Fe 8 crystals were investigated using a 95 and 141 GHz electron paramagnetic resonance (EPR) technique based on a standard superconducting quantum intererence device (SQUID) magnetometer. The technique

Standards and Standardization of Molecular Diagnostics

August 15, 2005
Author(s)
J P. Jakupciak, C D. O'Connell
DNA has become a major target for clinical laboratory testing over the past 5 years, and RNA testing is emerging for infectious disease and gene expression (1). To normalize laboratory results across different technology platforms as well as between

Exact Solution of a Field Theory Model of Frontal Photopolymerization

August 11, 2005
Author(s)
James A. Warren, J Cabral, Jack F. Douglas
Frontal photopolymerization (FPP) provides a versatile method for the rapid fabrication of solid polymer network materials by exposing photosensitive molecules to light. Dimensional control of structures created by this process is crucial in applications

High resolution, high collection efficiency in numerical aperture increasing lens microscopy of individual quantum dots

August 9, 2005
Author(s)
Zhiheng H. Liu, B. B. Goldberg, Stephen B. Ippolito, Anthony N. Vamivakas, M. S. Unlu, Richard Mirin
We demonstrate the application of a subsurface solid immersion technique to the photoluminescence spectroscopy of individual quantum dots. Contrasted with the conventional solid immersion microscopy, we used a numerical aperture increasing lens and moved

Chip-Scale Atomic Clocks at NIST

August 7, 2005
Author(s)
John E. Kitching, Svenja A. Knappe, Li-Anne Liew, John Moreland, Hugh Robinson, P Schwindt, V Shah, Vladislav Gerginov, Leo W. Hollberg
We describe recent efforts to develop microfabricated atomic frequency references capable of supporting a wide variety of commercial and military systems such as global positioning and wireless communication. These devices are anticipated to eventually

Uncertainty Budgets for Comparison Calibrations of Thermocouples

August 7, 2005
Author(s)
Dean C. Ripple, K Garrity
By means of concrete examples, we discuss the determination of an uncertainty budget for calibration of thermocouples by comparison techniques. In the first example, the calibration of a type T thermocouple (copper versus copper-nickel alloy) in a stirred

Injection Locking and Phase Control of Spin Transfer Nano-Oscillators

August 5, 2005
Author(s)
William Rippard, Matthew Pufall, Shehzaad F. Kaka, Thomas J. Silva, Stephen E. Russek, Jordan A. Katine
We have directly measured phase locking of spin transfer oscillators to an injected ac current. The oscillators lock to signals up to several hundred megahertz away from their natural oscillation frequencies, depending on the relative strength of the input

Long-Lived Qubit Memory Using Atomic Ions

August 5, 2005
Author(s)
C. Langer, R Ozeri, John D. Jost, J Chiaverini, B. L. DeMarco, A. Ben-Kish, Brad R. Blakestad, Joseph W. Britton, David Hume, Wayne M. Itano, Dietrich G. Leibfried, Rainer Reichle, Till P. Rosenband, Tobias Schaetz, Piet Schmidt, David J. Wineland
We demonstrate experimentally a robust quantum memory using a magnetic-field-independent hyperfine transition in 9Be + atomic ioin qubits at a magnetic field B=0.01194 T. We observe the single physical qubit memory coherence time to be greater than 10

Shaped Pupil Coronagraphs for Planet Finding: Optimization, Manufacturing, and Experimental Results

August 4, 2005
Author(s)
Jeremy Kasdin, Ruslan Belikov, James A. Beall, Robert J. Vanderbei, Michael G. Littman, Michael Carr, Amir Give''on
Current plans call for the first Terrestrial Planet Finder mission, TPF-C, to be a monolithic space telescope with a coronagraph for achieving high contrast. Our group at Princeton pioneered the concept of shaped pupils for high contrast imaging and planet

Spectral Matching With an LED-Based Spectrally Tunable Light Source

August 4, 2005
Author(s)
Irena Fryc, Steven W. Brown, Yoshihiro Ohno
A spectrally tunable light source using a large number of LEDs and an integrating sphere has been designed and constructed at the National Institute of Standards and Technology (NIST). The source is designed to have a capability of producing any visible

Uncertainties in Spherical Near-Field Antenna Measurements

August 3, 2005
Author(s)
Michael H. Francis, Ronald C. Wittmann, Jin-Seob Kang
A general approach is presented for estimating uncertainties in far-field parameters obtained from spherical near-field antenna measurements. The error is approximately bounded in terms of the uncertainty of the probe's receiving pattern and the

Scattering Length Determination From Trapped Pairs of Atoms

August 2, 2005
Author(s)
S Shresta, Eite Tiesinga, E L. Bolda, Carl J. Williams
A method is described for estimating effective scattering lengths via spectroscopy on a trapped pair of atoms. The method relies on the well known phenomena that the energy levels of two atoms in a harmonic trap are shifted by their collisional interaction

4th Annual PKI R&D Workshop "Multiple Paths to Trust" Proceedings

August 1, 2005
Author(s)
Clifford Neuman, William Polk, Nelson Hastings
NIST hosted the fourth annual Public Key Infrastructure (PKI) Research Workshop on April 19-21, 2005. The two and a half day event brought together PKI experts from academia, industry, and government to explore the remaining challenges in deploying public
Displaying 36801 - 36825 of 74377
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