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NIST Authors in Bold

Displaying 32501 - 32525 of 73929

Optical and structural study of GaN nanowires grown by catalyst-free molecular beam epitaxy. II. Sub-band-gap luminescence and electron irradiation effects

June 4, 2007
Author(s)
Larry Robins, Kristine A. Bertness, Joy Barker, Norman Sanford, John B. Schlager
GaN nanowires with diameters of 50-250nm, grown by catalyst-free molecular beam epitaxy, were characterized by photoluminescence (PL) and cathodoluminescence (CL) spectroscopy at temperatures from 3 to 297 K. Both as-grown samples and dispersions of

Precision Measurements using a 300 mV Josephson Arbitrary Waveform Synthesizer

June 4, 2007
Author(s)
Samuel P. Benz, Paul D. Dresselhaus, Charles J. Burroughs, Norman F. Bergren
We have developed a Josephson Digital-to-Analog Converter, otherwise know as a Josephson Arbitrary Waveform Synthesizer, with 300 mV peak output voltage. This is the first system of its kind with demonstrated quantum accuracy. We will show precision

Broadband Characterization of Multilayer Dielectric Thin-Films

June 3, 2007
Author(s)
Nathan D. Orloff, Jordi Mateu, Makoto Murakami, Ichiro Takeuchi, James C. Booth
We develop a measurement technique for obtaining the broadband complex permittivity of thin-film dielectric materials over the frequency range from 100 Hz-40 GHz. Such broad frequency coverage can only be accomplishe3d by combining lumped-element and

Detuning and Saturation of Superconducting Devices: Formulation and Measurements

June 3, 2007
Author(s)
Carlos Collado, Jordi Mateu, James Booth, J M. Callaghan
Saturation and detuning of High Temperture Superconducting (HTS) resonators and filters may occur due to the inherent nonlinear properties of the superconductor. In HTS transmission lines, these nonlinear properties introduce a dependence of the inductance

Effects of Ozonolysis and Subsequent Growth of Quantum Dots on the Electrical Properties of Freestanding Single-walled Carbon Nanotube Films

June 2, 2007
Author(s)
L C. Teague, S Banerjee, S S. Wong, Curt A. Richter, Bindhu Varughese, J Batteas
A significant challenge exists in probing the transport behavior of chemically modified single- walled carbon nanotubes (SWNTs). Thin films of SWNTs offer one facile approach to integration of these materials into electronics and sensing applications. Data

An Empirical Model for the Warm-Up Drift of a Commercial Harmonic Phase Standard

June 1, 2007
Author(s)
Jeffrey Jargon, Jolene Splett, Dominic F. Vecchia, Donald C. DeGroot
We develop an empirical model for the warm-up drift in a harmonic phase standard used to calibrate the phase distortion of a nonlinear vector network analyzer. The model enables us to estimate the time at which the standard reaches stability.

Anomalous Behavior of Teflon-Based Helium Permeation Flow Standards

June 1, 2007
Author(s)
Patrick J. Abbott, Justin H. Chow
Helium leak testing is a vital step in assuring product reliability for anything that must be packaged in a sealed container. Examples abound from blister packaging for pharmaceuticals to aluminum wheel rims for automobiles. In order to quantify detected

Comparison of Calibration Methods for Tristimulus Colorimeters

June 1, 2007
Author(s)
J L. Gardner
Uncertainties in source color measurements with a tristimulus colorimeter are estimated for calibration factors determined based on a known source spectral distribution or on accurate measurements of the spectral responsivities of the colorimeter channels

Computational Models of the Nano Probe Tip for Static Behaviors

June 1, 2007
Author(s)
Shaw C. Feng, Theodore V. Vorburger, Che B. Joung, Li Ma
As integrated circuits become smaller and faster, the measurement of line width must have less uncertainty and more versatility. The common requirement for uncertainty is less than 10 nanometers. The industrial need for versatility is three dimensional

Cone Calorimeter Analysis of UL-94 V-Rated Plastics

June 1, 2007
Author(s)
A B. Morgan, Matthew F. Bundy
Cone calorimeter analysis was conducted on 18 thermoplastics with different UL-94 vertical burn test (V) ratings. Ratings varied from V-0 to no rating (NR), and the types of thermoplastics included were polycarbonate (PC), acrylonitrile-butadiene-styrene

Connecting the Dots

June 1, 2007
Author(s)
Stephen D. Quinn
Establishing traceability from high-level Federal Information Security Management Act (FISMA) requirements to specific mechanisms to secure hardware and software poses challenges for the government?s systems security managers. Effectively using security

Current Ripple Effect on n-Value

June 1, 2007
Author(s)
Loren F. Goodrich, Jolene Splett
We studied the systematic effect of current ripple on the determination of n-value, which is the index of the shape of the electric field-current (E-I) curve. Commercial Nb 3Sn wires were measured with controlled amounts of ac ripple. Substitution-box

Disorder effects on the intrinsic nonlinear current density in YBa2Cu3O7

June 1, 2007
Author(s)
Brian M. Andersen, James Booth, P.J. Hirschfeld
We present harmonic generation measurements of the intrinsic nonlinear current density j2 of (YBCO) films at temperatures close the Tc. Experiments on a range of different quality samples allow us to extract the dependence of j2 on the penetration depth of

Dynamic Phasor Measurement Unit Test System

June 1, 2007
Author(s)
Gerard N. Stenbakken, Ming Zhou
This paper presents the plans and progress towards the development of a dynamic phasor measurement unit (PMU) performance test system at NIST. We describe an algorithm for taking time-synchronized samples of single-phase voltage and current power signals
Displaying 32501 - 32525 of 73929
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