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Displaying 30826 - 30850 of 74842

Directional Routing Protocols for Ad Hoc Networks

May 6, 2008
Author(s)
Hamid Gharavi, Bin Hu
This paper presents a directional routing approach for multihop ad-hoc networks, which has been applied to two on-demand routing protocols: namely Dynamic Source Routing (DRS) and Ad Hoc On-Demand Distance Vector Routing (AODV). Both DSR-based and AODV

Frequency evaluation of the doubly forbidden 1 S 0 - 3 P 0 transition in bosonic 174 Yb

May 6, 2008
Author(s)
Nicola Poli, Zeb Barber, Nathan D. Lemke, Christopher W. Oates, Tara Fortier, Scott Diddams, Leo W. Hollberg, James C. Bergquist, Anders Brusch, Steven R. Jefferts, Thomas P. Heavner, Tom Parker
We report an uncertainty evaluation of an optical lattice clock based on the 1S 0 – 3P 0 transition in the bosonic isotope 174Yb using magnetically induced spectroscopy. The uncertainty due to systematic effects has been reduced to less than 0.8Hz, which

Close Proximity Self-Aligned Shadow Mask for Sputter Deposition Onto a Membrane or Cavity

May 5, 2008
Author(s)
Ravi Kummamuru, L Hu, Lawrence P. Cook, M Y. Efremov, E A. Olson, Martin L. Green, L H. Allen
In this paper we report fabrication of a shadow mask designed for sputtering into cavities or on the back surface of freestanding silicon nitride (SiNx) membranes. Sputter deposition through a shadow mask typically results in spreading of the deposited

EVALUATION OF MULTI-SAMPLE MICRO-CAPILLARY RHEOMETER

May 5, 2008
Author(s)
Doyoung Moon, Anthony J. Bur, Kalman D. Migler
We present a Multi-sample Micro-capillary Rheometer (MMR) which is capable of measurements over a broad range of temperatures, viscosities and shear rates. The instrument is simple as the flow is generated by external gas pressure and the shear rate is

TRC Thermodynamic Tables, Non-Hydrocarbon Supplement H-135

May 5, 2008
Author(s)
Michael D. Frenkel
1. Table 23-2-(3.16400)-db - Pages db-2156.0 through db-2156.2: New table for 9-(3-cyclopentylpropyl)heptadecane containing the density for the real fluid at selected temperatures and pressures. 2. Table 23-2-(3.16430)-db - Pages db-2157.0 through db-2157

Broadband, frequency comb spectroscopy

May 4, 2008
Author(s)
Ian R. Coddington, William C. Swann, Nathan R. Newbury
A stabilized frequency comb provides a broadband array of highly resolved comb lines. Using a multiheterodyne technique, we measure the amplitude and phase of every comb line, allowing for massively parallel, high-resolution spectroscopy.

Improving squeezing purity from a KNbO 3 crystal by temperature tuning

May 4, 2008
Author(s)
Thomas Gerrits, Tracy S. Clement, Scott Glancy, Richard P. Mirin, Sae Woo Nam, Emanuel Knill
We show a method to increase the purity of a squeezed state generated by a femtosecond laser and down-conversion crystal. The method relies on temperature tuning the down- and up-converting crystals, which changes the spatial and spectral output mode of

Optical Microchip Detection of Nuclear Magnetic Resonance

May 4, 2008
Author(s)
M Ledbetter, I Savukov, D Budker, Vishal Shah, Svenja A. Knappe, John Kitching, S Xu, D Michalak, A Pines
We demonstrate optical detection of nuclear magnetic resonance on a microchip. A theoretical optimization indicates detection limits that are competitive with that demonstrated by microcoils in high magnetic fields, without requiring superconducting

Practical performance limits on optical frequency transfer over fiber optic links

May 4, 2008
Author(s)
Paul A. Williams, William C. Swann, Nathan R. Newbury
We present theory and experiment quantifying the limitations to stable transport of optical frequencies over optical fiber. These are fundamental fiber noise, propagation delay, bidirectional propagation and system noise in the measurement interferometers.

Nanotwin formation and its physical properties and effect on reliability of copper interconnects.

May 3, 2008
Author(s)
Di Xu, Vinay Sriram, Vidvuds Ozolins, Jenn-Ming Yang, K. N. Tu, Gery R. Stafford, Carlos R. Beauchamp, Inka Zienert, Holm Geisler, Petra Hofmann, Ehrenfried Zschech
Ultra-fine grained copper with a large amount of nano-scale twin boundaries has high mechanical strength and maintain normal electrical conductivity. The combination of these properties may lead to promising applications in future Si microelectronic

Electromagnetic Airframe Penetration Measurements of the FAA's 737-200

May 2, 2008
Author(s)
Chriss A. Grosvenor, David R. Novotny, Dennis G. Camell, Galen H. Koepke, Robert Johnk, Seturnino Canales
The National Institute of Standards and Technology has completed shielding effectiveness/penetration studies on three different aircraft types for the Federal Aviation Administration. The studies are used to understand the cavity coupling characteristics

Glass-Blown Spherical Microcells for Chip-Scale Atomic Devices

May 2, 2008
Author(s)
E. J. Eklund, A Shkel, Svenja A. Knappe, Elizabeth Donley, John Kitching
This paper presents an application of micro glass blowing, in which multiple glass spheres are simultaneously shaped on top of a silicon wafer and subsequently filled with rubidium. The fabrication process is based on etching cavities in silicon, followed

Adjustments to the NIST Realization of the ITS-90 from 5 K to 24.5561 K

May 1, 2008
Author(s)
Weston L. Tew, Christopher W. Meyer
Recent clarifications issued by the Consultative Committee on Thermometry (CCT) for the definitions of the equilibrium hydrogen (e-H2) triple points (TPs) and vapor-pressure points (VPs) have resulted in adjustments to the NIST-disseminated ITS-90 (T90) in

Airtightness and Ventilation in a Manufactured House: Pre-Retrofit Results

May 1, 2008
Author(s)
Steven J. Nabinger, Andrew K. Persily
A retrofit study is being conducted to investigate the airtightness, ventilation and energy impacts of tightening the exterior envelope and the heating and air conditioning system ductwork of a double section manufactured house. etc.

Assessment of ASCE 7 Standard Wind Load Factors for Tall Building Response Estimates

May 1, 2008
Author(s)
Rene D. Gabbai, William P. Fritz, Amelia P. Wright, Emil Simiu
Wind load factors incorporated in the ASCE 7 Standard are based on rough approximations of wind effects and the uncertainties inherent in them. These factors are routinely applied to tall building design, even though the original calculations on which they

Automated Continuous-Flow Gravimetric Hygrometer as a Primary Humidity Standard

May 1, 2008
Author(s)
Christopher W. Meyer, Joseph T. Hodges, R W. Hyland, Gregory E. Scace, J Valencia-Rodriguez, James R. Whetstone
A new primary gravimetric hygrometer has been completed at the National Institute of Standards and Technology (NIST). This apparatus determines the humidity in a steadily flowing gas stream by first separating the water from the carrier gas using

Ca Pre-Rinse Greatly Increases Plaque and Plaque Fluid F After a F Rinse

May 1, 2008
Author(s)
Gerald L. Vogel, Gary E. Schumacher, Laurence C. Chow, Shozo Takagi, Clifton M. Carey
This study examines if a Ca pre-rinse/F rinse increased plaque and plaque fluid F relative to the F rinse alone. Subjects (n = 13) accumulated plaque two days before rinsing with: (1) 12 mmol/L F (NaF), (2) 150 mmol/L Ca rinse, (3) the Ca rinse followed by

Designing high electron mobility transistor heterostructures with quantum dots for efficient, number-resolving photon detection

May 1, 2008
Author(s)
Mary A. Rowe, Eric Gansen, M. Greene, Danna Rosenberg, Todd E. Harvey, Mark Su, Robert Hadfield, Sae Woo Nam, Richard P. Mirin
We describe the design of the epitaxial layers for an efficient, photon-number-determining detector that utilizes a layer of self-assembled quantum dots as an optically addressable gate in a field-effect transistor. Our design features a dedicated
Displaying 30826 - 30850 of 74842