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Displaying 2076 - 2100 of 2581

A common-view disciplined oscillator

May 24, 2010
Author(s)
Michael A. Lombardi, Aaron P. Dahlen
This paper describes a common-view disciplined oscillator (CVDO) that locks to a reference time scale through the use of common-view Global Positioning System (GPS) satellite measurements. A Proportional-Integral-Derivative (PID) controller obtains near

Effect of strain, magnetic field and field angle on the critical current density of YBa 2 Cu 3 O 7-d coated conductors

May 18, 2010
Author(s)
Daniel C. van der Laan, J. F. Douglas, John (Jack) W. Ekin, Loren F. Goodrich, Theodore C. Stauffer, Cameron C. Clickner
A large, magnetic-field-dependent, reversible reduction in critical current density with axial strain in YBa 2Cu 3O 7-δ coated conductors at 75.9 K has been measured. This effect may have important implications for the performance of YBa 2Cu 3O 7-δ coated

Mid-IR frequency comb upconversion spectroscopy

May 16, 2010
Author(s)
Todd Johnson, Scott A. Diddams
We present a mid-infrared frequency comb generated via differency frequency mixing of a Yb femtosecond fiber laser. After passing through a methane gas sample, the MIR comb is upconverted and dispersed onto a CCD for detection.

Preserving quantum coherence using optimized open-loop control techniques

May 16, 2010
Author(s)
Michael J. Biercuk, Hermann Uys, Aaron Vandevender, Nobuyasu Shiga, Wayne M. Itano, John J. Bollinger
We describe experimental and theoretical studies of open-loop quantum control techniques known as dynamical decoupling (DD) for the suppression of decoherence-induced errors in quantum systems. Our experiments on trapped atomic ion qubits demonstrate that

Shell-dependent Blinking of CdSe-Based Core/Shell Nanocrystals

May 10, 2010
Author(s)
Seung Koo Shin, Bonghwan Chon, Sung Jun Lim, Wonjung Kim, Hyeong G. Kang, Taiha Joo, Jeeseong C. Hwang
Blinking of zinc-blende CdSe-based core/shell nanocrystals are studied as a function of shell materials. CdSe/ZnS, CdSe/ZnSe/ZnS, and CdSe/CdS/ZnS core/shell nanocrystals are prepared by epitaxial growth of two-to-six monolayers (MLs) of shell materials

Comparison of Air Kerma and Absorbed Dose to Water Measurements of Co-60 Radiation Beams in Radiotherapy

April 30, 2010
Author(s)
Ronaldo Minniti, I. Csete, A.G. Leiton, V. Sochor, A. Lapenas, J.-E Grindborg, I Jokelainen, H. Bjerke, J. Dobrovodsky, A. Megzifene, H.J. Costas, R. Ivanov, B. Vekic, J. Kokocinski, H.J. Cardoso, L. Buermann, W. Tiefenboeck, G. Stucki, E. van Dijk , M P. Toni, J.P. McCaffrey, C.N.M. da Silva, I Kharitonov, D. Webb, M Saravi, F. Delaunay
The results of the 25 participants of the EUROMET.RI(I)-K1 and EUROMET.RI(I)-K4 key comparisons are reported to support their relevant CMC claims being published or going to be published by the participant laboratories. The measured quantities were the air

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

The A 2E" - X 2A2' Transition of NO 3 Trapped in Solid Neon

April 7, 2010
Author(s)
Marilyn E. Jacox, Warren E. Thompson
NO3 has been stabilized in a neon matrix at 4.3 K in sufficient yield for detection of the absorptions between 7000 and 10000 cm-1 which arise from vibronically allowed transitions from its ground state to levels of the A 2E" state. The results confirm and

Influence of Ti and Ta doping on the irreversible strain limit of ternary Nb 3 Sn superconducting wires made by the restacked-rod process

April 1, 2010
Author(s)
Najib Cheggour, Loren F. Goodrich, Theodore C. Stauffer, Jolene D. Splett, Xifeng Lu, A. K. Ghosh, G. Ambrosio
Nb 3Sn superconducting wires made with restacked-rod process (RRP®) were found to have a dramatically improved resilience to axial tensile strain when alloyed with Ti as compared to Ta. Whereas Ta-alloyed Nb 3Sn in RRP wires showed permanent damage to its

Characterization of Soluble Anthradithiophene Derivatives

March 18, 2010
Author(s)
Brad Conrad, Calvin Chan, Marsha A. Loth, John E. Anthony, David J. Gundlach
We will discuss the growth and electrical measurements of a newly developed, partially fluorinated anthradithiophene (F-ADT) derivative with tert-butyldiphenylsilyl (TBDMS) side groups. Single crystals of the material can be readily grown and device hole

Toward scalable ion traps for quantum information processing

March 16, 2010
Author(s)
Jason Amini, Hermann Uys, Janus H. Wesenberg, Signe Seidelin, Joseph W. Britton, John J. Bollinger, Dietrich G. Leibfried, Christian Ospelkaus, Aaron Vandevender, David J. Wineland
The basic components for a quantum information processor using trapped ions have been demonstrated in a number of experiments. To perform complex algorithms that are not tractable with classical computers, these components need to be integrated and scaled

Enhancing Image Contrast Using Coherent States and Photon Number Resolving Detectors

March 15, 2010
Author(s)
Aaron Pearlman, Alexander E. Ling, Elizabeth A. Goldschmidt, Jingyun Fan, Christoph Wildfeuer, Alan L. Migdall
We experimentally map the transverse profile of diffraction-limited beams using photon number resolving detectors. We observe strong compression of diffracted beam profiles for high detected photon number. This effect leads to higher contrast than a

Low-loss superconducting resonant circuits using vacuum-gap -based microwave components

March 4, 2010
Author(s)
Katarina Cicak, Dale Li, Joshua Strong, Michael S. Allman, Fabio Altomare, Adam J. Sirois, Jed D. Whittaker, Raymond W. Simmonds
We have produced high quality resonant microwave circuits through developing a vacuum-gap technology for fabricating lumped-element capacitive and inductive components. We use micromachining to eliminate amorphous dielectric materials leaving vacuum in

Physics Laboratory: Activities, Accomplishments & Recognition 2008-2009

March 1, 2010
Author(s)
Jonathan E. Hardis
This report summarizes the research and measurement science carried out during 2008-2009 in the NIST Physics Laboratory. The Laboratory supports U.S. industry, government, and the scientific community by providing measurement services and research for

Weight Functions for Biases in Atomic Frequency Standards

March 1, 2010
Author(s)
Jon H. Shirley
Many perturbations that affect atomic frequency standards vary during the period of measurement. To include this time variation, we introduce three time-dependent weight functions built from the solution of the unperturbed equations of motion of a two

Frequency Comparison of Two High-Accuracy Al+ Optical Clocks

February 17, 2010
Author(s)
Chin-Wen Chou, David Hume, J.C. Koelemeij, David J. Wineland, Till P. Rosenband
We have constructed an optical clock with a fractional frequency inaccuracy of 8.6e-18, based on quantum logic spectroscopy of an Al+ ion. A simultaneously trapped Mg+ ion serves to sympathetically laser-cool the Al+ ion and detect its quantum state. The
Displaying 2076 - 2100 of 2581
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