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Search Publications

NIST Authors in Bold

Displaying 35926 - 35950 of 73697

Simulating Fire Effects on Complex Building Structures.

September 18, 2005
Author(s)
Howard R. Baum
The purpose of this lecture is to assess the current state of our ability to simulate the consequences of a fire in a large building, and suggest some areas where improvement is needed. Attention is focused on the coupling of fire dynamics simulations and

Chip-Scale Atomic Frequency References

September 16, 2005
Author(s)
John E. Kitching, Svenja A. Knappe, Li-Anne Liew, P Schwindt, Vladislav Gerginov, V Shah, John Moreland, Alan Brannon, J Breitbarth, Z Popovic, Leo W. Hollberg
We describe recent efforts at NIST to develop microfabricated, chip-scale atomic frequency references based on microfabrication techniques commonly used in micro electro mechanical systems (MEMS). These devices are projected to have a volume of 1 cm 3, a

Atomic vapor cells for chip-scale atomic clocks with improved long-term frequency stability

September 15, 2005
Author(s)
Svenja A. Knappe, Vladislav Gerginov, P Schwindt, V Shah, Leo W. Hollberg, John E. Kitching, Hugh Robinson
A novel technique for microfabricating alkali atom vapor cells is described, in which alkali atoms are evaporated into a micromachined cell cavity through a glass nozzle. A cell of interior volume 1 mm 3, containing 87Rb and a buffer gas, was made in this

High Field X-Ray Diffraction Studies on Gd 5 (Ge 2-x Fe x )Si 2 (x = 0.05 and 0.2)

September 15, 2005
Author(s)
Jim L. Her, Keiichi Koyama, Kazuo Watanabe, Virgil Provenzano, F Fu, Robert D. Shull
We performed the X-ray diffraction measurements in magnetic fields up to 5 T for Gd5(Ge1.95Fe0.05)Si2 and Gd5(Ge1.8Fe0.2)Si2 which are noted recently as related materials for magnetic refrigerants. With heating from 8 K, the matrix of Gd5(Ge1.95Fe0.05)Si2

Mutual phase-locking of microwave spin torque nano-oscillators

September 15, 2005
Author(s)
Shehzaad F. Kaka, Matthew Pufall, William Rippard, Thomas J. Silva, Stephen E. Russek, Jordan A. Katine
The spin torque effect that occurs in nanometre-scale magnetic multilayer devices can be used to generate steady- state microwave signals in response to a d.c. electrical current. This establishes a new functionality for magneto-electronic structures that

A Novel Approach to Fingerprint Image Quality

September 14, 2005
Author(s)
Elham Tabassi, Charles L. Wilson
We present a novel measure of fingerprint image quality, which can be used to estimate fingerprint match performance. This means presenting the matcher with good quality fingerprint images will result in high matcher performance, and vice versa, the

Challenges in Characterizing Sealant

September 14, 2005
Author(s)
Christopher C. White, Donald L. Hunston
Sealant is one of the very few major consumer products valued primarily for its rheological and adhesive properties. While, these materials may appear to be simple elastic solids, upon further examination, their behavior can be extremely complex. In this

Multilayer and functional coatings on carbon nanotubes using atomic layer deposition

September 14, 2005
Author(s)
Cari F. Herrmann, F Fabreguette, Dudley Finch, Roy H. Geiss, S M. George
Atomic layer deposition can be used to deposit ultra thin and conformal films on substrates with very high aspect ratios such as nanotubes and nanowires. In this paper, we demonstrate that functionalized and multilayered ALD coatings can be deposited

NIST F1: Recent improvements and a resulting accuracy of df/f=0.53x10 -15

September 13, 2005
Author(s)
Thomas P. Heavner, Steven R. Jefferts, Elizabeth Donley, Jon H. Shirley, Tom Parker
In the last several years we have made many improvements to NIST-F1 (a laser-cooled Cs fountain primary frequency standard) resulting in over a factor of 2 reduction in the uncertainty in the realization of the SI second. The two most recent accuracy

Operation of the NIST-F1 Cesium Fountain Primary Frequency Standard with a Maser Ensemble

September 13, 2005
Author(s)
Thomas E. Parker, Steven R. Jefferts, Thomas P. Heavner, Elizabeth A. Donley
The operation of a caesium fountain primary frequency standard is greatly influenced by the characteristics of two other important capabilities. The first is a stable frequency reference and the second is the frequency-transfer system. A stable frequency

The Exact Multiplicative Complexity of the Hamming Weight Function

September 13, 2005
Author(s)
Rene C. Peralta, Joan Boyar
We consider the problem of computing the Hamming weight of an n-bit vector using a circuit with gates for addition and multiplication modulo 2 (alternatively, XOR and conjunction gates) only. The number of multiplications necessary and sufficient to build

Examination of Multicomponent Diffusion Between Two Ni-Base Superalloys

September 11, 2005
Author(s)
Carelyn E. Campbell, William J. Boettinger, T Hansen, P Merewether, B A. Mueller
The interdiffusion at 1293 degree C between two multicomponent Ni-base superalloys, Rene-N4 and ene-N5, was assessed by measuring the composition vs. distance curves and by comparing the measured curves to predictions obtained using a diffusion mobility

Observed Correlation of Sn Oxide film to Sn Whisker Growth in Sn-Cu electrodeposit for pb-free Solders

September 11, 2005
Author(s)
Kil-Won Moon, C E. Johnson, Maureen E. Williams, O Kongstein, Gery R. Stafford, C A. Handwerker, William J. Boettinger
To evaluate the effects of the oxide film on Sn whisker growth, a bright Sn-Cu electrodeposit was tested in an ultrahigh vacuum chamber with Auger analysis. After Ar+ ion beam cleaning to remove the oxide film, the sample was analyzed and stored in the

A Modular System Architecture for Agile Assembly of Nanocomponents using Optical Tweezers

September 10, 2005
Author(s)
Arvind K. Balijepalli, Thomas W. LeBrun, Cedric V. Gagnon, Yong-Gu Lee, Nicholas G. Dagalakis
In order to realize the flexibility optical trapping offers as a nanoassembly tool, we need to develop natural and intuitiveinterfaces to assemble large quantities of nanocomponents quickly and cheaply. We propose a system to create such aninterface that

A Solution for Wireless Privacy and Payments based on E-cash

September 9, 2005
Author(s)
A Karygiannis, Y. Tsiounis, A. Kayias
With wireless capable devices becoming more and more accessible, there is an increasing need for standardization of wireless networking. One of the most utilized standards that is deployed by many current devices (including theWindows XP OS) for building

Issues in Line Edge and Linewidth Roughness Metrology

September 9, 2005
Author(s)
John S. Villarrubia
In semiconductor electronics applications, line edge and linewidth roughness are generally measured using a root mean square (RMS) metric. The true value of RMS roughness depends upon the length of edge or line that is measured and the chosen sampling
Displaying 35926 - 35950 of 73697
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