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Displaying 24626 - 24650 of 73970

Ultralow phase noise microwave generation with an Er:fiber-based optical frequency divider

August 15, 2011
Author(s)
Franklyn J. Quinlan, Tara M. Fortier, Matthew S. Kirchner, Jennifer A. Taylor, Michael J. Thorpe, Nathan D. Lemke, Andrew D. Ludlow, Yanyi Jiang, Christopher W. Oates, Scott A. Diddams
We present an optical frequency divider based on a 200 MHz repetition rate Er:fiber mode-locked laser that, when locked to a stable optical frequency reference, generates microwave signals with absolute phase noise that is equal to or better than cryogenic

A digital time scale at the National Institute of Standards and Technology

August 13, 2011
Author(s)
Stefania Romisch, Steven R. Jefferts, Thomas E. Parker
An integrated time scale has as primary data unit of duration (time interval) defined by atomic standards according to the definition of the SI second. The availability of more than one atomic standard allows for averaging, thereby improving the

Dual comb-based characterization of rapidly tuned lasers

August 13, 2011
Author(s)
Fabrizio R. Giorgetta, Esther Baumann, Ian R. Coddington, William C. Swann, Nathan R. Newbury, Zeb Barber, Peter Roos
Time-resolved, high-accuracy and high-resolution spectroscopy of rapidly tuned cw lasers is critical to realizing their full potential for sensing, but is not possible with conventional spectrometers. We demonstrate a coherent dual-comb-based spectrometer

Measurement of Shielding Effectiveness of Electrically-Small Enclosures

August 13, 2011
Author(s)
Christopher L. Holloway, Colton R. Dunlap, John M. Ladbury, Joshua A. Gordon, Jason B. Coder, Galen H. Koepke
In the following we propose a technique for determining the shielding effectiveness (SE) an electrically small enclosure. In particular, we use this technique to explore the shielding characteristics of a rectangular box used to shield a satellite based

Real-Time Generation of the SIM Time Scale (SIMT) from International Clock Comparisons

August 13, 2011
Author(s)
Michael A. Lombardi, Jose M. Lopez, Andrew N. Novick, Francisco Jimenez, Nelida Diaz-Munoz, Eduardo de Carlos Lopez, Jean-Simon Boulanger, Raymond Pelletier, Ricardo de Carvalho, Raul Solis, Harold Sanchez, Liz C. Forero, Junior Gordon, Daniel Perez, Eduardo Bances, Leonardo Trigo, Victor Masi, Henry Postigo, Anthony Questelles, Anselm Gittens, Rodrigo Ramos P.
The Sistema Interamericano de Metrologia (SIM) is one of the world’s five major regional metrology organizations (RMOs). The SIM members are the national metrology institutes (NMIs) located in the 34 nations of the Organization of American States (OAS)

Calibration of dynamic sensors for noncontact-atomic force microscopy

August 12, 2011
Author(s)
Gordon A. Shaw, Jon R. Pratt, Zeina J. Kubarych
Access to quantitative information on surface forces in noncontact-atomic force microscopy (NC-AFM) requires the accurate calibration of several key sensor parameters. This work outlines a dynamic method for calibrating the spring constant of tuning fork

Guide for Security-Focused Configuration Management of Information Systems

August 12, 2011
Author(s)
L A. Johnson, Kelley L. Dempsey, Ronald S. Ross, Sarbari Gupta, Dennis Bailey
The purpose of Special Publication 800-128, Guide for Security-Focused Configuration Management of Information Systems, is to provide guidelines for organizations responsible for managing and administering the security of federal information systems and

Hyperspectral Imaging and Analysis of Single Erythrocytes

August 12, 2011
Author(s)
Ji Y. Lee, Matthew L. Clarke, Fuyuki Tokumasu, John F. Lesoine, David W. Allen, Robert C. Chang, Maritoni A. Litorja, Jeeseong Hwang
We report a hyperspectral imaging and analysis technique to resolve unique physico-chemical characteristics of subcellular substances in single erythrocytes. We constructed a microscope system installed with a spectral light engine capable of controlling

Gallium nitride nanowire electromechanical resonators with piezoresistive readout

August 11, 2011
Author(s)
Kristine A. Bertness, Jason M. Gray, Norman A. Sanford, Charles T. Rogers
We report on the fabrication, piezoresistive readout, and frequency response of doubly-clamped c-axis gallium nitride (GaN) nanowire (NW) resonators that show mechanical quality factors exceeding 10,000. The devices are fabricated using a combination of

Graphene-metal interconnect: an atomistic simulation

August 11, 2011
Author(s)
Alexander Y. Smolyanitsky, Vinod K. Tewary
We develop a set of computationally efficient and accurate interatomic interactions for an atomistic simulation of the properties of graphene on nickel surface. The approach is based on the modified embedded atom method (MEAM) for the C-C and Ni-Ni

Microwave quantum logic gates for trapped ions

August 11, 2011
Author(s)
Dietrich G. Leibfried, Christian Ospelkaus, Ulrich J. Warring, Yves Colombe, Kenton R. Brown, J. M. Amini, David J. Wineland
Achieving control over physical systems at the quantum level is a goal shared by scientific fields as diverse as metrology, information processing, simulation and chemistry. For trapped atomic ions, the quantized motional and internal degrees of freedom

Modeling Enzymatic Kinetic Pathways for Ring-Opening Lactone Polymerization

August 11, 2011
Author(s)
Peter M. Johnson, Santanu S. Kundu, Kathryn Beers
A unified kinetic pathway for the enzyme catalyzed polymerization and degradation of poly(ε-caprolactone) was developed. This model tracks the complete distribution of individual chain lengths, both enzyme-bound and in solution, and successfully predicts

Potassium Induced Charge Transfer Effects in OPE-based Molecular Layers

August 11, 2011
Author(s)
Steven W. Robey, Gregory J. Dutton
The impact of potassium (K) addition on the electronic structure of oligo- (phenylene ethynylene) (OPE) and –NO2 substituted OPE (NO2-OPE) self-assembled monolayers was examined using ultraviolet photoemission. Addition below 0.5 K/molecule produced rigid

ALD for reliable nanowire self-assembly on microfabricated electrodes

August 10, 2011
Author(s)
Joseph J. Brown, Kristine A. Bertness, Alicia I. Baca, Bright M. Victor
The use of ALD TiO 2 surface coating improves dielectrophoretic assembly yield of individual GaN nanowires on micro-fabricated structures by as much as 67%. With titanium dioxide coating, individual nanowires were placed across suspended electrode pairs in

NIST-SP 500-291, NIST Cloud Computing Standards Roadmap

August 10, 2011
Author(s)
Michael D. Hogan, Fang Liu, Annie W. Sokol, Tong Jin
The NIST Cloud Computing Standards Roadmap Working Group has surveyed the existing standards landscape for security, portability, and interoperability standards/models/studies/use cases, etc., relevant to cloud computing. Using this available information

Selective Binding of O 2 over N 2 in Redox- Active Metal-Organic Framework with Open Iron(II) Coordination Sites

August 10, 2011
Author(s)
Eric D. Bloch, Leslie J. Murray, Wendy Queen, Sachin Chavan, Sergey N. Maximoff, Julian P. Bigi, Rajamani Krishna, Vanessa Peterson, Fernande Grandjean, Berend Smit, Silvia Bordiga, Craig Brown, Jeffrey R. Long
The air-free reaction of FeCl 2 and H 4dobdc (dobdc 4- = 2,5-dioxido-1,4- benzenedicarboxylate) in a mixture of DMF and methanol affords Fe 2(dobdc), a metal-organic framework isostructural to M 2(dobdc) (M = Mg 2+, Mn 2+, Co 2+, Ni 2+, Zn 2+). The

Using Block Copolymer Self-Assembly to Imprint the Crystallization of Polymer Dendrites

August 10, 2011
Author(s)
Sangcheol Kim, Alamgir Karim, Jack F. Douglas, Christopher L. Soles, R M. Briber
We utilize the self-assembly of cylinder-forming block copolymer (BCP) films to create templates for dendritic polymer crystallization patterns. This templating was achieved by simply spin-casting thin films from a solution containing both the BCP

Analyses of a Cantilever-Beam Based Instrument for Evaluating the Development of Polymerization Stresses

August 9, 2011
Author(s)
Martin Chiang, Anthony A. Giuseppetti, Joy Dunkers, Jing Qian, Sheng Lin-Gibson, Gary E. Schumacher, Joseph M. Antonucci
Analytical and finite element analyses have been performed on a cantilever-beam based methodology (tensometer) for evaluating the development of stresses as the concomitant of constrained polymerization shrinkage. A guideline for designing a tensometer

Controlling Formation of Atomic Step Morphology on Micro-patterned Si (100)

August 9, 2011
Author(s)
Kai Li, Pradeep Namboodiri, Sumanth B. Chikkamaranahalli, Gheorghe Stan, Ravikiran Attota, Joseph Fu, Richard M. Silver
Micro scale features are fabricated on Si (100) surfaces using lithographic techniques and then thermally processed in an ultra high vacuum (UHV) environment. Samples are flash heated at 1200 °C and further annealed at 1050 °C for 18 hours. The surface
Displaying 24626 - 24650 of 73970
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