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Metrology

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Displaying 1526 - 1550 of 2718

Choosing test positions for laser tracker evaluation and future Standards development

July 15, 2010
Author(s)
Balasubramanian Muralikrishnan, Daniel S. Sawyer, Christopher J. Blackburn, Steven D. Phillips, Craig M. Shakarji, Ed Morse, Robert Bridges
A working group within the ISO TC 213 committee is developing a draft document [11] for evaluating the performance of laser trackers. The ASME B89.4.19 Standard [1] and the draft VDI/VDE 2617 part 10 [2] describe some useful tests that are incorporated

Active Millimeter-Wave Imaging: Standoff Detection of Concealed Weapons

July 13, 2010
Author(s)
Randy Direen, David R. Novotny, Katherine MacReynolds
A near-field planar scanner is used to construct images of a nearby scene illuminated with millimeter-wave frequencies. We present our initial work in active millimeter-wave imaging, and how it applies to the detection of concealed weapons.

Temperature-dependent dielectric relaxation in bismuch zinc niobate thin films.

July 12, 2010
Author(s)
James C. Booth, Nathan D. Orloff, Joel Cagnon, Jiwei Lu, Susanne Stemmer
We apply broadband measurement techniques to determine the dielectric permittivity of Bi1.5Zn1.0Nb1.5O7 (BZN) thin films over the frequency range 1 kHz to 40 GHz. At room temperature, the permittivity function shows relaxation at high frequencies (1 GHz)

Recent Developments in Thermoelectric Metrology at NIST

July 10, 2010
Author(s)
Winnie K. Wong-Ng, Joshua B. Martin, Nathan Lowhorn, Makoto Otani, Evan L. Thomas, Martin L. Green, Jason Hattrick-Simpers, Yonggao Y. Yan, Thanh Tran, Jihui Yang
We have successfully developed several important thermoelectric metrologies in recent years at NIST. First, a low temperature (10 K to 390 K) Seebeck coefficient Standard Reference Material (SRM™), Bi2Te3, which is crucial for inter-laboratory data

The Decomposition and Isomerization of 5-Methylhex-1-yl Radical

July 9, 2010
Author(s)
Iftikhar A. Awan, William S. McGivern, Wing Tsang, Jeffrey A. Manion
The decomposition and isomerization reactions of the 5-methylhex-1-yl radical (1-5MeH) have been studied at temperatures of 889 K to 1064 K and pressures of 1.6 bar to 2.2 bar using the single pulse shock tube technique. The radical of interest was

High-voltage Nanoimprint Lithography of Refractory Metal Film

July 1, 2010
Author(s)
John A. Dagata, Natalia Farkas, R Ramsier
Local oxidation of metal, semiconductor, and polymer surfaces has provided a common basis from which to explore fundamental principles of nanolithography and prototype functional nanostructures for many years now. This article summarizes an investigation

Performance Measurements for Evaluating Static and Dynamic Multiple Human Detection and Tracking Systems in Unstructured Environments

June 30, 2010
Author(s)
Bodt Bodt, Richard Camden, Harry A. Scott, Adam S. Jacoff, Tsai H. Hong, Tommy Chang, Richard J. Norcross, Anthony Downs, Ann Virts
The Army Research Laboratory (ARL) Robotics Collaborative Technology Alliance (CTA) conducted an assessment and evaluation of multiple algorithms for real-time detection of pedestrians in Laser Detection and Ranging (LADAR) and video sensor data taken from

Standard Photoacoustic Spectrometer: Model and Validation using O2 A-Band Spectra

June 30, 2010
Author(s)
Keith A. Gillis, Daniel K. Havey, Joseph T. Hodges
We model and measure the absolute response of an intensity-modulated photoacoustic spectrometer comprising a 10 cm long resonator and having a Q-factor of approximately 30. We present a detailed theoretical analysis of the system and predict its response

Multi-Scale Pore Morphology in Vapor-Deposited Yttria-Stabilized Zirconia Coatings

June 16, 2010
Author(s)
Derek D. Hass, H. Zhao, Tabbetha A. Dobbins, Andrew J. Allen, Andrew Slifka, H. N. Wadley
A high pressure, electron-beam directed-vapor deposition process has been used to deposit partially stabilized zirconia containing 7 % yttria by mass at deposition pressures of 7.5 Pa to 23 Pa. Anisotropic ultra-small-angle X-ray scattering (USAXS) was

Role of Nanoparticles in Life Cycle of Nanocomposites

June 15, 2010
Author(s)
Xiaohong Gu, Guodong Chen, Minhua Zhao, Stephanie S. Watson, Paul E. Stutzman, Tinh Nguyen, Joannie W. Chin, Jonathan W. Martin
The objective of this study is to investigate the role of ZnO nanoparticles in the life cycle of a waterborne polyurethane (PU) nanocomposite during UV exposure. The effects of loadings and sizes of ZnO nanoparticles on photodegradation of ZnO/PU films

Calibrations of Current-to-Voltage Transimpedance Amplifiers Using Electrical Standards

June 13, 2010
Author(s)
Howard W. Yoon, George P. Eppeldauer, Dean G. Jarrett, Thomas C. Larason, Wan-Seop Kim
For photocurrent measurements with low uncertainties, a wide-dynamic range current-to-voltage converter traceable to resistance standards has been developed at the NIST. The design and calibration of the converter standard are described. For validation

Comparison of Near-Field Methods at NIST

June 13, 2010
Author(s)
Katherine MacReynolds
A comparison of the planar, spherical and cylindrical near-field techniques was completed at the National Institute of Standards and Technology (NIST) for a Ku-band cassegrain reflector antenna. This paper discusses the measurement results for the near-to

INTERCOMPARISON OF W-BAND STANDARD GAIN HORN ANTENNAS

June 13, 2010
Author(s)
Katherine MacReynolds, J. Kang, N. Kang, D. Gentle, Michael H. Francis
An intercomparison of power gain for W-band (75 GHz to 110 GHz) standard horn antennas has been performed among KRISS, NPL and NIST. This paper describes the comparison and its measurement results.

Nanoparticle size and shape evaluation using the TSOM optical microscopy method

June 6, 2010
Author(s)
Ravikiran Attota, Richard J. Kasica, Lei Chen, Premsagar P. Kavuri, Richard M. Silver, Andras Vladar
We present a novel optical TSOM (through-focus scanning optical microscopy - pronounced as 'tee-som') method that produces nanoscale dimensional measurement sensitivity using a conventional optical microscope. The TSOM method uses optical information from

Degradation and Nanoparticle Release of Nanocomposite Coatings Exposed to UV Radiation

June 2, 2010
Author(s)
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Xiaohong Gu, Justin M. Gorham, Paul E. Stutzman, Alexander J. Shapiro, Walter E. Byrd, Joannie W. Chin
The release of nanoparticles from nanocomposite coatings during their life cycle potentially has negative effects to the environments and presents a roadblock to their uses. The degradation and nanoparticle release of amine-cured epoxy coatings containing

Cylindrical Acoustic Resonator for the Re-determination of the Boltzmann Constant

June 1, 2010
Author(s)
J.T. Zhang, H. Lin, X.J. Feng, Keith A. Gillis, Michael R. Moldover
We describe progress towards re-determining the Boltzmann constant k B using two fixed-path, gas-filled, cylindrical, acoustic cavity resonators. The longitudinal acoustic resonance modes of a cylindrical cavity have lower quality factors Q than the radial

Feasibility of an Accurate Dynamic Standard for Water Flow

June 1, 2010
Author(s)
Iosif I. Shinder, Michael R. Moldover
We used NIST's primary water flow standard to study the feasibility of accurately determining mass flow rates m dot of water "dynamically," that is from the time derivative of the weight W of the collection tank: m dot,dynamic = (dW/dt)/g. When data for a

Standard Reference Materials for Analysis of Dietary Supplements

June 1, 2010
Author(s)
Katherine E. Sharpless, David L. Duewer
NIST, in collaboration with the National Institutes of Health Office of Dietary Supplements (NIH-ODS) and the Food and Drug Administration (FDA) is producing Standard Reference Materials (SRMs) for dietary supplements. This paper describes the how these
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