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Displaying 34276 - 34300 of 73832

Reverse Noise Measurement and Use in Device Characterization

June 10, 2006
Author(s)
James P. Randa, Tom McKay, Susan L. Sweeney, Dave K. Walker, Lawrence Wagner, David R. Greenberg, Jon Tao, G. Ali Rezvani
We review the concept of reverse noise measurements in the context of on-wafer transistor noise characterization. Several different applications of reverse noise measurements are suggested and demonstrated. Reverse measurements can be used to check

Correlating Molecular Design to Microstructure in Thermally Convertible Oligothiophenes: The Effect of Branched versus Linear End Groups

June 8, 2006
Author(s)
Dean M. DeLongchamp, Youngsuk Jung, Daniel A. Fischer, Eric K. Lin, P C. Chang, V Subramanian, A R. Murphy, J M. Frechet
The thin film microstructure development of functionalized oligothiophenes with branched, thermally removable groups at each end of conjugated cores with five, six, and seven thiophene rings was monitored during their thermal conversion from solution

Soft X-Ray Absorption Spectroscopy of the MgB 2 Boron K Edge in an MgB 2 /Mg Composite

June 8, 2006
Author(s)
Daniel A. Fischer, A R. Moodenbaugh, Q Li, G Gu, Y Zhu, J W. Davenport, D O. Welch, H Su
Soft x-ray absorption (XAS), using fluorescence yield, was used to study the boron K near edge in MgB2 superconductor. The sample consists of MgB2 crystallites randomly oriented in a magnesium matrix. Abrasion of the sample surface in vacuum provides a

Display Measurements for Flat Panel Displays

June 7, 2006
Author(s)
Edward F. Kelley
In this tutorial, problems encountered in making common measurements on flat-panel displays are reviewed, equipment limitations are explored, and properly managed stray light is stressed. Reflection description and measurement apparatus robustness are

Energy Levels and Spectral Lines of Ne VIII

June 7, 2006
Author(s)
Alexander Kramida, M-C Buchet-Poulizac
All experimental data on the valence-shell-excited and inner-shell-excited spectra of Li-like neon, including previously unpublished beam-foil spectroscopy data, have been compiled and critically evaluated. Seventeen spectral lines have been newly

An Octagonal Architecture for High Strength PIT Nb 3 Sn Conductors

June 6, 2006
Author(s)
L. R. Motowidlo, E Barzi, D. Turrioni, Najib Cheggour, Loren F. Goodrich
Powder-in-Tube (PIT) Nb 3Sn conductors have been fabricated utilizing a low-cost intermetallic Cu 5Sn 4 powder as the tin source. A novel octagonal PIT design that incorporates dispersion strengthened copper as well as a hexagonal PIT design were

Solution and Surface Composition Gradients via Microfluidic Confinement: Fabrication of a Statistical-Copolymer-Brush Composition Gradient

June 6, 2006
Author(s)
Chang Xu, Susan E. Barnes, Tao Wu, Daniel A. Fischer, Dean M. DeLongchamp, J Batteas, Kathryn L. Beers
A simple method to generate solution gradients through microfluidic confinement is described. The solution gradient inside a microchannel was formed by varying the relative infusion rates of two solutions that differed in compositions. The establishment

A Local Oscillator for Chip-Scale Atomic Clocks at NIST

June 5, 2006
Author(s)
Alan Brannon, J Breitbarth, Z Popovic, Vladislav Gerginov, V Shah, Svenja A. Knappe, Leo W. Hollberg, John E. Kitching
We report the first local oscillator (LO) demonstrating viability in terms of performance, size, and power, for chip-scale atomic clocks (CSAC) at the National Institute of Standards and Technology in Boulder, CO. This volgate-controlled oscillator (VCO)

Absolute Optical Frequency Measurements with a Fractional Uncertainty at 1 x 10 -15

June 5, 2006
Author(s)
Jason Stalnaker, Scott A. Diddams, Leo W. Hollberg, Kyoungsik Kim, Elizabeth A. Donley, Thomas P. Heavner, Steven R. Jefferts, Filippo Levi, Thomas E. Parker, James C. Bergquist, Wayne M. Itano, Marie J. Jensen, Luca Lorini, Windell Oskay, Tara M. Fortier, J Torgerson
We report the technical details specific to our recent measurements of the optical frequency of the mercury single-ion clock in terms of the SI second as realized by the NIST-F1 cesium fountain clock. In these measurements the total fractional uncertainty

Active light-shift stabilization in modulated CPT clocks

June 5, 2006
Author(s)
V Shah, P Schwindt, Vladislav Gerginov, Svenja A. Knappe, Leo W. Hollberg, John E. Kitching
We demonstrate a simple technique to significantly improve the long-term frequency stability in atomic clocks based on coherent population trapping (CPT). In this technique an additional servo is used to control the local oscillator power level to ensure

Comparison of AM noise in commercial amplifiers and oscillators at X-band

June 5, 2006
Author(s)
Archita Hati, David A. Howe, Craig Nelson
In this paper we discuss the importance of amplitude modulated (AM) noise. AM noise is often neglected and considered as a minor problem. However, AM noise can become very important in high performance systems that require ultra-low phase modulated (PM)

Kinetics Governing Phase Separation of Nanostructured Sn(x)Ge(1a 'x) Alloys.

June 5, 2006
Author(s)
Regina Regan, Harry A. Atwater, Jonathan E. Guyer, Erik Meserole, Mark S. Gorrsky
We have studied the dynamic phenomenon of SnxGe1a 'x/Ge phase separation during deposition by molecular beam epitaxy on Ge(001) substrates.Phase-separation leads to the formation of direct bandgap semiconductor nanowire arrays embedded in Ge oriented along

Low Phase Noise Amplifier and Oscillator using Feed-Forward Technique at 10 GHz

June 5, 2006
Author(s)
Archita Hati, Craig Nelson, David A. Howe
We discuss the performance of a feed-forward amplifier (FFA) at 10 GHz. The feed-forward method is primarily used to suppress intermodulation distortion in amplifiers to suppress up-converted near-DC noise. The main amplifier in this configuration is a low

Optical and microwave frequency synthesis with an integrated fiber frequency comb

June 5, 2006
Author(s)
Ingmar Hartl, Martin E. Fermann, William C. Swann, John J. McFerran, Ian R. Coddington, Qudsia Quraishi, Scott Diddams, Nathan R. Newbury, Carston Langrock, Martin M. Fejer, Paul S. Westbrook, Jeffrey W. Nicholson, K Feder
We demonstrate optical coherence over a broad spectral range of two independent fiber frequency combs. Additionally, we demonstrate microwave stability of better than 2x10 -14 in 1 second for an optically integrated fiber frequency comb.

Relativity and Timing in X-ray Pulsar Navigation

June 5, 2006
Author(s)
Neil Ashby, David A. Howe
XNAV is a technology demonstration that will use photons from X-ray pulsars for navigation and spacecraft attitude determination. This paper summarizes relativistic effects in the context of XNAV. It also characterizes the primary task in the time domain

Stability measurements of the Ca and Yb Optical Frequency Standards

June 5, 2006
Author(s)
Christopher W. Oates, C Hoyt, Yann Le Coq, Zeb Barber, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Leo W. Hollberg
In this paper we describe two types of optical atomic clocks. The first is based on freely expanding calcium atoms and is optimized for experimental simplicity and high stability. The second is based on Yb atoms confined to an optical lattice that is
Displaying 34276 - 34300 of 73832
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