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Displaying 30826 - 30850 of 73788

Complete waveform characterization at NIST

June 8, 2008
Author(s)
Paul D. Hale, Tracy S. Clement, Darryl A. Keenan, Dylan F. Williams, Arkadiusz C. Lewandowski, C. M. Wang, Andrew Dienstfrey
We present a method for calibrating the voltage a pulse generator delivers to a load at every point in the measured waveform epoch. The calibration includes an equivalent circuit model of the generator so that the user can calculate how the generator will

High Rate Tensile Strength Measurements of Frangible Bullets Using a Kolsky Bar

June 8, 2008
Author(s)
Steven P. Mates, Richard L. Rhorer, Stephen W. Banovic, Eric P. Whitenton, Richard J. Fields
The tensile strength of frangible bullets is measured by a high rate diametral compression test (DCT) performed with a Kolsky Bar. Frangible bullets, meant to disintegrate on impact by brittle failure, also exhibit significant plasticity in compression. As

High resolution spectroscopy using fiber-laser frequency combs

June 8, 2008
Author(s)
Ian R. Coddington, William C. Swann, Nathan R. Newbury
The output of a femtosecond fiber laser can be both spectrally broadened and stabilized, thereby providing a broadband coherent source in the near infrared. In the frequency domain, the result is a frequency comb with frequency stabilities at the

Noise-parameter measurement with automated variable terminations

June 8, 2008
Author(s)
Dazhen Gu, Dave K. Walker, James P. Randa
NIST has upgraded its measurement capability of noise parameters on low-noise amplifiers with a variable termination unit in the 1 to 12.4 GHz range. Such a unit allows improved time efficiency in the noise-temperature measurements used to de-embed noise

Permittivity and Permeability and the Basis of Effective Parameters

June 8, 2008
Author(s)
James R. Baker-Jarvis, Michael D. Janezic, Billy F. Riddle
The concepts of effective permittivity and permeability are used throughout the literature to describe both highly heterogeneous materials, inhomogeneous materials, and small collections of molecules. In this paper we study definitions of the permittivity

Uncertainty Analysis for Noise-Parameter Measurements

June 8, 2008
Author(s)
James P. Randa
A brief summary is presented for the uncertainty analysis for measurements of noise parameters of amplifiers and transistors, in both connectorized (coaxial) and on-wafer environments. We treat both the X-parameters, which are based on the wave

Improving Correlations with Inelastic Loss

June 6, 2008
Author(s)
James V. Porto
Correlations are one of the central features of modern condensed matter physics. They arise in systems where the behavior of any given particle in a system depends strongly on all the other particles. Such correlations are what help distinguish the

A Regional Comparison of Calibration Results for Type K Thermocouple Wire From 100 C to 1100 C

June 5, 2008
Author(s)
K Garrity, Dean C. Ripple, M Araya, C R. Cabrera, L Cordova Murillo, M E. de Vanegas, D J. Gee, Edwin Guillen, S Martinez-Martinez, Edgar Mendez-Lango, L Mussio, S G. Petkovic, K N. Quelhas, G Rangugni, O Robatto, E Von Borrries Rocha
Under the auspices of the Inter-american Metrology System (SIM), the National Institute of Standards and Technology (NIST) initiated a regional comparison for type K thermocouples from 100 deg. C to 1100 deg. C, with 11 participating countries. Each

Mixed Analog-Digital Instrumentation for Software-Defined-Radio Characterization

June 5, 2008
Author(s)
Catherine A. Remley, Nuno Carvalho, Pedro Cruz, Kevin Gard
This paper presents a new type of analog-digital mixed-domain instrument that is specially tailored for software defined radio characterization. The instrument allows the utilization of analog instruments such as vector signal analyzers and network

Proficiency Testing for Achieving Accreditation in Thermometry

June 5, 2008
Author(s)
Sally S. Bruce, Gregory F. Strouse
The establishment of traceability is an essential component of laboratory accreditation for Calibration laboratories accredited by the National Voluntary Laboratory Accreditation Program (NVLAP). Traceability requires that an unbroken chain of comparisons

An Ontological Modeling Platform

June 4, 2008
Author(s)
V.C. Liang, Conrad E. Bock, XuanFang Zha
The Ontological Modeling Platform described in this paper is a class library for extended ontological operations, to support extension of ontology languages, composition of interconnected elements, and high-level product modeling services, such as

ASTM E57 - 3D Imaging Systems

June 4, 2008
Author(s)
Geraldine S. Cheok, Alan M. Lytle, Kamel S. Saidi
As the applications for 3D imaging systems continue to grow, the need for standards to evaluate these systems has become more critical. The ASTM E57 3D Imaging committee established in 2006 was formed specifically to develop standard terminology, test

Guide to Using Programs to Estimate UV Dosage and Damage

June 3, 2008
Author(s)
Brian Dickens
The system of programs described in this paper is concerned with estimating the damage ensuing from exposure of specimens in dry and humid atmospheres to UV and visible radiation covering the solar range. Damage is monitored quantitatively by changes in IR

Pair Correlation Functions in Mixtures of Lennard-Jones Particles

June 3, 2008
Author(s)
Raymond D. Mountain, Yedhud A. Ben-Naim
The pair correlation functions for a mixture of two Lennard-Jones (LJ) particles were computed by both the Percus-Yevick equations and by molecular dynamics. The changes in the pair correlation function resulting from changes in the composition of the
Displaying 30826 - 30850 of 73788
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