Journal of Research of the National Institute of Standards and Technology articles from July 2004

Journal of Research of the National Institute of Standards and Technology archives from July 2004

Initial NIST AC QHR measurements.(quantized hall resistance)
July 1, 2004... We demonstrate that dc quantized Hall resistance (dc QHR) guideline properties and dc and ac QHR values can be measured without changing sample probe lead connections at the QHR device, and report ac QHR values that converge to the dc QHR value...

Frequency-domain models for nonlinear microwave devices based on large-signal measurements.
July 1, 2004... In this paper, we introduce nonlinear large-signal scattering (S) parameters, a new type of frequency-domain mapping that relates incident and reflected signals. We present a general form of nonlinear large-signal S-parameters and show that...

Nonlinearity measurements of high-power laser detectors at NIST.
July 1, 2004... We briefly explain the fundamentals of detector nonlinearity applicable to both electrical and optical nonlinearity measurements. We specifically discuss the attenuation method for optical nonlinearity measurement that the NIST system is based...

Two primary standards for low flows of gases.
July 1, 2004... We describe two primary standards for gas flow in the range from 0.1 to 1000 [micro]mol/s. (1 [micro]mol/s [congruent to] 1.3 c[m.sup.3]/min at 0[degrees]C and 1 atmosphere.) The first standard is a volumetric technique in which measurements of...

Evaluation of handheld radionuclide identifiers.
July 1, 2004... Characterization of commercially available instruments for measurement and identification of unknown radionuclides was carried out in support of the development and testing of the American National Standards Institute (ANSI) standard, N42.34,...