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Displaying 1351 - 1375 of 2503

The lifetime of 4p54d levels in highly ionized atoms

February 16, 2016
Author(s)
G. Gaigalas, P. Rynkun, Charlotte F. Fischer
Energy levels, lifetimes, and wave function compositions have been computed for all atomic states of the 4p6 and 4p54d configurations using a single-reference (SR) configuration state along with single- and double-substitutions (SD) to generate expansions

An Overview of Spectral Imaging of Human Skin toward Face Recognition

February 13, 2016
Author(s)
David W. Allen
Spectral imaging is a form of remote sensing that provides a means of collecting information from surroundings without physical contact. Differences in spectral reflectance over the electromagnetic spectrum allow for the detection, classification, or

Rapid, broadband spectroscopic temperature measurement of CO 2 using VIPA spectroscopy

January 28, 2016
Author(s)
Andrew M. Klose, Gabriel Ycas, Flavio Caldas da Cruz, Daniel I. Maser, Scott Diddams
Rapid spectroscopic temperature measurements of a sealed carbon dioxide sample cell were realized with an optical frequency comb combined with a two-dimensional dispersive spectrometer. A supercontinuum laser source based on an erbium mode-locked laser was

Demonstration of near-IR line-referenced electro-optical laser comb for precision radial velocity measurement in astronomy

January 27, 2016
Author(s)
Scott A. Diddams, K Vahala, J Li, Gabriel G. Ycas, P Plavchan, S Leifer, J Sandhu, G Vasisht, P Chen, P Gao, J Gagne, M Bottom, E.C. Martin, M.P. Fitzgerald, G Doppmann, C Beichman, X Yi
We describe a successful effort to produce a laser comb around 1.55 micron in the astronomical H band (1.5-1.8 micron) using a method based on a line-referenced, electro-optical-modulation frequency comb (LR-EOFC). The LR-EOFC is a spectrum of equally

High-contrast and fast electrochromic switching enabled by plasmonics

January 27, 2016
Author(s)
Ting Xu, Erich C. Walter, Amit Agrawal, Christopher C. Bohn, Jeyavel Velmurugan, Wenqi Zhu, Henri Lezec, Albert A. Talin
With vibrant colours and simple, room-temperature processing methods, electrochromic polymers have attracted attention as active materials for flexible, low-power-consuming devices. However, slow switching speeds in devices realized to date, as well as the

Mechanically mediated microwave frequency conversion

January 26, 2016
Author(s)
Florent Q. Lecocq, Jeremy B. Clark, Raymond W. Simmonds, Jose A. Aumentado, John D. Teufel
We report the observation of efficient and low-noise frequency conversion between two microwave modes, mediated by the motion of a mechanical resonator subjected to radiation pressure. We achieve the coherent conversion of more than 10^{12} photons/s with

GPS Jamming and GPS Carrier-Phase Time Transfer

January 25, 2016
Author(s)
Jian Yao, Marc A. Weiss, Charles Curry, Judah Levine
This paper studies the impact of GPS jamming on GPS carrier-phase time transfer. To study this issue, at NIST, we have installed a commercial GPS jamming detector since 2014 April. During 2014 April – 2015 April, the detector detected more than 100 jamming

Polymer Glass-Formation in Variable Dimension

January 14, 2016
Author(s)
Jack F. Douglas, Freed Karl, Wensheng Xu
We explore the nature of glass-formation in variable spatial dimensionality (d) based on the generalized entropy theory, a synthesis of the Adam-Gibbs model with direct computation of the configurational entropy of polymer fluids using an established

Survival analysis approach to account for non-exponential decay rate effects in lifetime experiments

January 13, 2016
Author(s)
Kevin J. Coakley, Maynard S. Dewey, Michael G. Huber, Hans P. Mumm, Alan Keith Thompson, Andrew T. Yue, C. R. Huffer, P. R. Huffman, C. M. O'Shaughnessy, K. W. Schelhammer, D. E. Marley
In experiments that measure the lifetime of trapped particles, in addition to loss mechanisms with exponential survival probability functions, particles can be lost by mechanisms with non-exponential survival probability functions. Failure to account for

DBSR_HF: A B-spline Dirac-Hartree-Fock program

January 8, 2016
Author(s)
O Zatsarinny, Charlotte F. Fischer
A B-spline version of a general Dirac-Hartree-Fock program is described. The usual differential equations are replaced by set of generalized eigenvalue problems of the form (Ha . åa B)Pa = 0, where Pa designates the two-component relativistic orbital in B

Spectrum and Energy Levels of Five-Times Ionized Zirconium (Zr VI)

January 5, 2016
Author(s)
Joseph Reader, Mark D. Lindsay
The spectrum of five-times-ionized zirconium Zr VI was observed from 160 Å to 2000 Å with sliding spark discharges on 10.7-m normal- and grazing-incidence spectrographs. The existing analysis of this spectrum [Khan Z. A. et al. 1985 Phys. Scr. 31 837] was

NIST Time and Frequency Bulletin

January 1, 2016
Author(s)
Karen L. Hansen Lichtfuss
The Time and Frequency Bulletin provides information on performance of time scales and a variety of broadcasts (and related information) to users of the NIST services

Direct observation of Feshbach enhanced s-wave scattering of fermions

December 17, 2015
Author(s)
Dina Genkina, Lauren M. Aycock, Hsin I Lu, Ian B. Spielman, Benjamin K. Stuhl
We directly measured the s-wave scattering cross-section of ultracold 40K atoms across the 20.2 mT Feshbach resonance by colliding pairs of degenerate Fermi gases (DFGs) and imaging the scattered atoms. Owing to DFG’s low density, few atoms scattered, even

Multi-element logic gates for trapped-ion qubits

December 17, 2015
Author(s)
Ting Rei Tan, John P. Gaebler, Yiheng Lin, Yong Wan, Ryan S. Bowler, Dietrich G. Leibfried, David J. Wineland
Precision control over hybrid physical systems at the quantum level is of general importance in physics. For trapped-ions, a hybrid system formed of different species introduces extra degrees of freedom that can be exploited to expand and refine the

A strong loophole-free test of local realism

December 16, 2015
Author(s)
Lynden K. Shalm, Evan Meyer-Scott, B. G. Christensen, Peter L. Bierhorst, Michael A. Wayne, Deny Hamel, Martin J. Stevens, Thomas Gerrits, Scott C. Glancy, Michael S. Allman, Kevin J. Coakley, Shellee D. Dyer, Adriana E. Lita, Varun B. Verma, Joshua C. Bienfang, Alan L. Migdall, Yanbao Zhang, William Farr, Francesco Marsili, Matthew D. Shaw, Jeffrey Stern, Carlos Abellan, Waldimar Amaya, Valerio Pruneri, Thomas Jennewein, Morgan Mitchell, P. G. Kwiat, Richard P. Mirin, Emanuel H. Knill, Sae Woo Nam
We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high

Accurate multiconfiguration calculations of energy levels, lifetimes and transition rates for the silicon isoelectronic sequence: Ti IX - Ge XIX, Sr XXV, Zr XXVII, Mo XXIX

December 6, 2015
Author(s)
P. Jonsson, L Radziute, G. Gaigalas, M. Godefroid, J P. Marques, T Brage, Charlotte F. Fischer, I. P. Grant
Multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and relativistic configuration interaction (RCI) calculations are performed for states of the 3s23p2, 3s3p3 and 3s23p3d configurations in the Si-like ions Ti IX - Ge XIX, Sr XXV, Zr XXVII, Mo XXIX
Displaying 1351 - 1375 of 2503
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