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Search Publications

NIST Authors in Bold

Displaying 18151 - 18175 of 74219

AC Waveform Source Referenced to a Programmable Josephson Voltage Standard

August 24, 2014
Author(s)
Alain Rufenacht, Charles J. Burroughs, Bryan C. Waltrip, Stephane P. Solve, Paul D. Dresselhaus, Samuel P. Benz
We are integrating an AC waveform source into our Programmable Josephson Voltage Standard system (PJVS). The objective is to provide a convenient, highly automated quantum-referenced source for ac voltage metrology that does not require the use of a

Accurate High-Ohmic Resistance Measurement Techniques up to 1 Pohm

August 24, 2014
Author(s)
Dean G. Jarrett, Gert Rietveld, Beat Jeckelmann
An overview is presented on precision high-ohmic resistance measurements for values of 100 Mohmand above. The two main measurement techniques in this resistance range are discussed, the current integration technique and the adapted Wheatstone bridge. The

Alignment and testing of the NIST Calculable Capacitor

August 24, 2014
Author(s)
Yicheng Wang, Felipe Guzman, Corey A. Stambaugh, Radek Smid, Hugo Zuniga Calvo, Andrew D. Koffman, Jon R. Pratt, John R. Lawall
This paper reports progress on the NIST effort to develop a new calculable capacitor, focusing on improvement of the guard electrode motion control as well as issues associated with the overall electrode alignment. Design of a multi-wavelength Fabry-Perot

Construction and Performance of the NIST-4 Magnet System

August 24, 2014
Author(s)
Frank C. Seifert, Alireza R. Panna, Leon S. Chao, Yusi A. Cao, Darine El Haddad, Shisong Li, Stephan Schlamminger, Jon R. Pratt, Heeju Choi, Lori Haley
A watt balance is a promising instrument to realize the unit of mass at the kilogram level. The magnet system is one of the key elements of such an instrument. For the new watt balance currently under construction at the National Institute of Standards and

Heterodyne interferometer with subnanometer accuracy

August 24, 2014
Author(s)
Darine El Haddad, Frank C. Seifert, Stephan Schlamminger, Leon S. Chao, David B. Newell, Jon R. Pratt
This paper gives a brief description of the laser interferometer system designed for the next generation watt balance experiment aimed to realize the unit of mass by direct link to Planck constant at the National Institute of Standards and Technology. The

Measurement of the Boltzmann Constant with Noise Thermometry at NIM

August 24, 2014
Author(s)
Jifeng Qu, Kunli Zhou, Horst Rogalla, Samuel Benz, Yunfeng Fu
Since 2010 we have been developing a quantum-voltage-calibrated Johnson noise thermometer at NIM to measure the Boltzmann constant k. With recent improvements in grounding and shielding of the electronics, and matching of the noise sources and transmission

Photonic-assisted Endoscopic Analysis of Guided W-band Pulses

August 24, 2014
Author(s)
Jeffrey A. Jargon, DongJoon Lee, JaeYong Kwon
We present a photonic-assisted time-domain measurement technique for exploring millimeter-wave propagation through a W-band waveguide. The electric fields, guided inside a rectangular waveguide, are sampled using a sub-millimeter-scale electro-optic probe

Relative Humidity Effects on Rectangular Waveguide Thermistor Sensors

August 24, 2014
Author(s)
Thomas P. Crowley
A correlation between the relative humidity nd the effective efficiency of several rectangular waveguide thermistor sensors has been observed. The difference between effective efficiency measurements made at 10 % and 30 % relative humidity can be 10 times

Systematic Error Resolved in NIST Johnson Noise Thermometer

August 24, 2014
Author(s)
Alessio Pollarolo, Weston L. Tew, Horst Rogalla, Samuel P. Benz
In the Johnson Noise Thermometry approach, Boltzmann’s constant k is obtained as the ratio of the noise power measured across a sense resistor at the triple point of water and the noise power measured for a synthesized reference waveform. The reference

The Design of the NEW NIST-4 Watt Balance

August 24, 2014
Author(s)
Leon S. Chao, Stephan Schlamminger, Frank C. Seifert, Yusi A. Cao, Darine El Haddad, David B. Newell, Jon R. Pratt
The design of the new permanent-magnet driven watt balance and novel mechanical features will demonstrate the high-precision capabilities of a large complex mass measurement system with expected overall uncertainties on the order of 3 parts in 10^8.

The Measurement of the Local Acceleration of Gravity for the NIST4 Watt Balance

August 24, 2014
Author(s)
David B. Newell, Jacques Liard, Leon S. Chao, Yusi A. Cao, Frank C. Seifert, Darine El Haddad, Jon R. Pratt, Stephan Schlamminger
A new watt balance is being constructed at NIST in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. We describe the procedures used and give results for the

Rapid PCR Protocols for Forensic DNA Typing on Six Thermal Cycling Platforms

August 22, 2014
Author(s)
Peter Vallone, Erica Romsos
Rapid PCR protocols for the amplification of typing short tandem repeat multiplexes were evaluated on 6 different thermal cyclers. PCR primers from the commercially available multiplex short tandem repeat typing kit Identifiler were used to target 15 STR

Fullerene-free polymer solar cells with strongly reduced bimolecular recombination and field- independent charge carrier generation

August 21, 2014
Author(s)
Steffen Roland, Marcel Schubert, Brian A. Collins, Jona Kurpiers, Zhihua Chen, Antonio Facchetti, Harald Ade, Dieter Neher
Photogeneration, recombination and transport of free charge carriers in all-polymer bulk heterojunction solar cells incorporating P3HT as donor and P(NDI2OD-T2) as acceptor polymer have been investigated by the use of time delayed collection field (TDCF)

Methane Storage in Metal-Organic Frameworks

August 21, 2014
Author(s)
Yabing He, Wei Zhou, Guodong Qian, Banglin Chen
Natural gas (NG), whose main component is methane, is an attractive fuel for vehicular applications. Realization of safe, cheap and convenient means and materials for high-capacity methane storage can significantly facilitate the implementation of natural

Phase Segregation of Sulfonate Groups in Nafion Interface Lamellae, Quantified via Neutron Reflectometry Fitting Techniques for Multi-Layered Structures

August 21, 2014
Author(s)
Steven C. DeCaluwe, Paul A. Kienzle, Pavan Bhargava, Andrew M. Baker, Joseph Dura
Neutron reflectometry analysis methods are developed and used to determine the composition depth profile in cases where the structure is no known a priori. These methods, including statistical methods, sophisticated fitting routines, and coupling multiple

Single-shot security for one-time memories in the isolated qubits model

August 21, 2014
Author(s)
Yi-Kai Liu
One-time memories (OTM's) are simple, tamper-resistant cryptographic devices, which can be used to implement sophisticated functionalities such as one-time programs. OTM's cannot exist in a fully-classical world, or in a fully-quantum world, but there is

Sustainability Characterization for Additive Manufacturing

August 21, 2014
Author(s)
Kevin W. Lyons, Satyandra K. Gupta
Additive manufacturing (AM) has the potential to create geometrically complex parts that require a high degree of customization, using less material and producing less waste. Recent studies have shown that AM can be an economically viable option for use by
Displaying 18151 - 18175 of 74219