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NIST Authors in Bold

Displaying 1576 - 1600 of 2755

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

Modeling and metrology of metallic nanowires with application to microwave interconnects

May 23, 2010
Author(s)
Kichul Kim, Thomas M. Wallis, Paul Rice, Chin J. Chiang, Atif A. Imtiaz, Pavel Kabos, Jintao Zhang
Abstract: Broadband characterization of individual metallic nanowires for microwave interconnect applications is discussed. Circuit and method of moments (MoM) modeling are benchmarked using a set of coplanar waveguide (CPW) test devices with microwire Au

Simultaneous XAFS Measurements of Multiple Samples

May 17, 2010
Author(s)
Bruce D. Ravel, C. Scorzato, D. P. Siddons, S. D. Kelly, S. R. Bare
A four-channel ionization chamber has been designed, constructed and tested. This ionization chamber allows X-ray absorption spectra to be collected in transmission from up to four samples simultaneously. This results in spectra that are free of systematic

Uncertainty Budgeting for Range Calibration

May 10, 2010
Author(s)
Ruediger Kessel, Raghu N. Kacker, Klaus-Dieter Sommer
The Guide to the Expression of Uncertainty (GUM) in Measurement established a general procedure to evaluate measurement uncertainty. The Guide covers only the evaluation of a single result or a set of results. Modern measurement instruments and procedures

Solutions for Determining Equibiaxial Substrate Strain for Dynamic Cell Culture

May 2, 2010
Author(s)
Martin Y. Chiang, Tianle Cheng, Lisa Pakstis, Joy P. Dunkers
Empirical and analytical solutions are derived in this study to determine the equibiaxial strain on a flexible substrate upon which the cells can be cultured. The empirical formula is based on the mechanistic constraint and a regression analysis of results

NEXT GENERATION GUARDED HAMON TRANSFER STANDARDS FOR HIGH RESISTANCE

May 1, 2010
Author(s)
Dean G. Jarrett, Andrew J. Dupree
Guarded Hamon transfer standards have been used at NIST for decades for scaling to high resistance levels. A recent project has been undertaken to apply improved designs in guarded Hamon transfer standards to the 1 MΩ to 100 MΩ ranges with the larger goal

Code-division SQUID multiplexing

April 23, 2010
Author(s)
Michael D. Niemack, Kent D. Irwin, Joern Beyer, Hsiao-Mei Cho, William B. Doriese, Gene C. Hilton, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Leila R. Vale
Multiplexed superconducting quantum interference device (SQUID) readout systems are a critical technology for measuring large arrays of superconducting transition-edge sensor (TES) detectors. Current successful SQUID multiplexing architectures are
Displaying 1576 - 1600 of 2755
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