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Displaying 1551 - 1575 of 2503

Common Symbols Used in Gas and Liquid Chromatographic Schematic Diagrams

June 4, 2014
Author(s)
Thomas J. Bruno
The literature of gas and liquid chromatography frequently contains schematic diagrams that depict analytical apparatus and peripherals. The interpretation of such diagrams can be facilitated by the following graphics that show the most common symbols used

Figures of Merit

June 4, 2014
Author(s)
Thomas J. Bruno
In the interpretation of results from a particular technique, one often must evaluate the performance of the measurement on the basis of objective measures that are called figures of merit. The following table provides a description of the more common

Large-area irradiance-mode spectral response measurements of solar cells by a light-emitting-diode- based integrating sphere source

May 30, 2014
Author(s)
Behrang H. Hamadani, John F. Roller, Andrew M. Shore, Brian P. Dougherty, Howard W. Yoon
An irradiance-mode absolute differential spectral response measurement system based on a light emitting diode (LED) array is described. The LEDs are coupled to an integrating sphere whose output irradiance is uniform to better than 2 % over an area of 160

Fe I Oscillator Strengths for the Gaia-ESO Survey

May 27, 2014
Author(s)
Matthew Ruffoni, E. A. Den Hartog, James E. Lawler, N. R. Brewer, K. Lind, Gillian Nave, J C. Pickering
The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale study of multielement chemical abundances of some 100; 000 stars in the Milky Way with the ultimate aim of quantifying the formation history and evolution of young, mature and

Collapse of the Cross-spectral Function

May 22, 2014
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe
Cross-spectral analysis is a mathematical tool for extracting the power spectral density of a correlated signal from two time series in the presence of uncorrelated interfering signals. We demonstrate and explain a set of amplitude and phase conditions

Correlation Measurements between PM and AM Noise in Oscillators

May 22, 2014
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We discuss techniques for measuring the correlation between phase modulated (PM) and amplitude modulated (AM) noise in an oscillator and report results of such correlation in a few selected oscillators of similar size, weight, power consumption and

Frequency Biases in a Cold-Atom Coherent Population Trapping Clock

May 22, 2014
Author(s)
Elizabeth A. Donley, Eric M. Blanshan, Francois-Xavier R. Esnault, John E. Kitching
A compact cold-atom clock based on coherent population trapping (CPT) has been developed. The clock typically demonstrates a short-term fractional frequency stability of 4x10 -11/√τ limited by frequency noise on the interrogation lasers. The largest two

Optical hyperpolarization and NMR detection of 129 Xe on a microfluidic chip

May 20, 2014
Author(s)
Ricardo Jimenez Martinez, Daniel J. Kennedy, Michael Rosenbluh, Elizabeth A. Donley, Svenja A. Knappe, Scott J. Seltzer, Hattie L. Ring, Vikram S. Bajaj, John E. Kitching
We present a microfluidic chip that enables the production of laser-polarized 129Xe gas and its optical detection. Production of polarized 129Xe and its remote detection is achieved under flowing gas conditions at low magnetic fields in two separate

Phase and coherence of optical microresonator frequency combs

May 9, 2014
Author(s)
William Loh, Pascal P. Del'Haye, Scott B. Papp, Scott A. Diddams
We investigate the phase and coherence properties of microresonator combs using a combination of theoretical analysis, numerical simulation, and experimental measurement. Our analysis reveals that the comb phase in many cases does not stabilize to an

A Half Century of Cryogenics and CSA

May 5, 2014
Author(s)
Ray Radebaugh
1964 seems just like yesterday to me, yet it was 50 years ago. The Cryogenic Society of America (CSA) was born that year, and I was just beginning my professional career in cryogenics. Because I have been active in cryogenics for all these past 50 years, I

ATOMIC DATA AND COLLISIONAL-RADIATIVE MODEL FOR BERYLLIUM AND ITS IONS

May 2, 2014
Author(s)
D. Kondratyev, O. Marchuk, Leonid Vainshtein, Igor Bray, Dmitry Fursa, Yuri Ralchenko, D. Fursa
In this work we present a collisional-radiative model constructed for all ionization stages of beryllium. Convergent close-coupling, K-matrix and Coulomb-Born-exchange methods were applied to calculate the necessary atomic data. For neutral beryllium atom

First Accuracy Evaluation of NIST-F2

May 1, 2014
Author(s)
Thomas P. Heavner, Steven R. Jefferts, Jon H. Shirley, Thomas E. Parker, Elizabeth A. Donley, Neil Ashby, Stephan E. Barlow, Filippo Levi, Giovanni Costanzo
We report the first accuracy evaluation of NIST-F2, a second generation laser-cooled Cesium fountain primary standard developed at NIST with a cryogenic (Liquid Nitrogen) microwave cavity and flight region. The 80 K atom interrogation environment reduces

WWVB Time Signal Broadcast: A New Enhanced Broadcast Format and Multi-Mode Receiver

May 1, 2014
Author(s)
John P. Lowe, Yingsi Liang, Oren Eliezer, Dinesh Rajan
WWVB is a broadcast station, operated by the National Institute of Standards and Technology, that has been broadcasting time information to radio-controlled clocks (RCC) throughout the continental US since 1965. The transmitted information includes the

Coordinate-space approach to vacuum polarization

April 28, 2014
Author(s)
Peter J. Mohr, P Indelicatio, J. Sapirstein
The vacuum-polarization correction for bound electrons or muons is examined. The objective is to formulate a framework for calculating the correction from bound-state quantum electrodynamics entirely in coordinate space, including the Uehling potential

Time-resolved double-slit interference pattern measurement with entangled photons

April 28, 2014
Author(s)
Lynden K. Shalm, Thomas Jennewein, Kevin Resch, Piotr Kolenderski, Carmelo Scarcella, Kelsey D. Johnsen Johnsen, Deny Hamel, Cahterine Holloway, Simone Tisa, Alberto Tosi
The double-slit experiment strikingly demonstrates the wave-particle duality of quantum objects. In this famous experiment, particles pass one-by-one through a pair of slits and are detected on a distant screen. A distinct wave-like pattern emerges after

Energy Levels And Spectral Lines Of Quadruply Ionized Iron (Fe V)

April 24, 2014
Author(s)
Alexander Kramida
This compilation revises and extends the previously recommended list of energy levels of quadruply ionized iron (Fe V) and provides a comprehensive list of observed spectral lines and transition probabilities in this spectrum. The new level optimization

Sensor Calibration and Characterization to Meet Climate Monitoring Requirements

April 24, 2014
Author(s)
Catherine C. Cooksey, Gerald T. Fraser, Howard W. Yoon
The challenge of detecting small changes in the Earth's climate system over decadal and longer time scales places stringent requirements on environmental monitoring systems. Sensors must be well calibrated and maintain their calibration in challenging

Preparation of nanocomposite plasmonic films made from cellulose nanocrystals or mesoporous silica decorated with unidirectionally aligned gold nanorods

April 11, 2014
Author(s)
Michael Campbell, Qingkun Liu, Aric Sanders, Julian Evans, Ivan I. Smalyukh
Using liquid crystalline self-assembly of cellulose nanocrystals, we achieve long-range alignment of anisotropic metal nanoparticles in colloidal nanocrystal dispersions that are then used to deposit thin structured films with ordering features highly

The hyperfine Paschen-Back Faraday effect

March 26, 2014
Author(s)
Svenja A. Knappe, M.A. Zentile, Rebecca Andrews, L. Weller, C.S. Adams, I.G. Hughes
We investigate experimentally and theoretically the Faraday effect in an atomic medium in the hyperfine Paschen-Back regime, where the Zeeman interaction is larger than the hyperfine splitting. We use a small permanent magnet and a micro-fabricated vapour

Dual-polarization-sensitive kinetic inductance detectors for balloon-borne, sub-millimeter polarimetry

March 20, 2014
Author(s)
James A. Beall, Dan Becker, Justus Brevik, Hsiao-Mei Cho, Gene C. Hilton, Kent D. Irwin, Dale Li, David P. Pappas, Jeffrey L. Van Lanen, Johannes Hubmayr
We are developing arrays of kinetic inductance detectors for sub-millimeter polarimetry that will be deployed on the BLAST balloon-borne instrument. The array is feedhorn-coupled, and each pixel contains two lumped-element kinetic inductance detectors

Optical amplification and pulse interleaving for low noise photonics microwave generation

March 12, 2014
Author(s)
Franklyn J. Quinlan, Frederick N. Baynes, Tara M. Fortier, Qiugui Zhou, Allen Cross, Joe Campbelll, Scott A. Diddams
We investigate the impact of pulse interleaving and optical amplification on the spectral purity of microwave signals generated by photodetecting the pulsed output of an Er:fiber-based optical frequency comb. It is shown that the microwave phase noise
Displaying 1551 - 1575 of 2503
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