An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
https://www.nist.gov/publications/search
Search Publications
NIST Authors in Bold
Displaying 34776 - 34800 of 73832
Joseph J. Berry, Martin Stevens, Richard Mirin, Kevin L. Silverman
We report the use of continuous wave spectral hole burning to perform high-resolution spectroscopy of the homogeneous linewidth of self-assembled InGaAs/GaAs quantum dots at low temperature. We use this technique to examine the power broadening behavior of
We calculate entropy-temperature curves for interact in bosons in unit filled optical lattices for both homogeneous and harmonically trapped situations, and use them to understand how adiabatic changes in the lattice depth affect the temperature of the
We present results of first-principles calculations of the frequency-dependent polarizabilities of all alkali atoms for light in the wavelength range 300-1600 nm, with particular attention to wavelengths of common infrared lasers. We parameterize our
The performance of Light Emitting Diodes (LEDs), including efficiency, flux level, lifetime, and the variation of color, is advancing at a remarkable pace. LEDs are increasingly used for many applications including automotive, aviation, display
A new metric for evaluating the color quality of light sources is being developed at NIST, in close contact with the lighting industry and the CIE. The current CIE Color Rendering Index (CRI) is outdated and has several known deficiencies. The CRI only
All experimental data on Ne VII, including previously unpublished beam-foil spectroscopy data, have been compiled and critically evaluated. More than a hundred spectral lines have been newly identified. For 40 transitions, the previous identifications have
Recent measurements reveal striking trends in the variation of fragility (the strength of the temperature dependence of the fluid viscosity) of glass-forming polymer liquids with monomer structure and pressure. The elucidation of the physical origin of
In recent years, heightened security concerns have prompted increased interest in radiation portal monitors, instruments capable of detecting, and in some cases identifying, gamma-ray and neutron-emitting radioactive material passing through them. Along
A quantitative comparison of real and computer-generated (model) cement paste microstructures based on the analysis of three-dimensional image sets is presented. In addition to a visual presentation of extracted two-dimensional images, the comparison is
This Paper describes an implementation of the proposed IEEE 1451.0 and 1451.5 Standards. The implemented systsem was developed based on the object-oriented framework of the IEEE 1451 standards using UML tools and Java programming language. The system
The performance of an atomic clock or magnetometer based on CPT is determined by the resonance width and the signal-to-noise ratio. In particular, a large signal amplitude results in a high stability for a clock or a high sensitivity for a magnetometer
Igor Levin, Eric J. Cockayne, M W. Lufaso, Joseph C. Woicik, James E. Maslar
Local structures and cation distributions in perovskite Ca(Zr, Ti)O3 solid solutions were analyzed using X-ray absorption fine structure and pair-distribution functions obtained from total neutron scattering. The analyses revealed that the Zr-O and Ti-O
The importance of developing better tools for observing the status of the North American Power Grid is described. Focus is on the performance of the Phase Measurement Units being deployed to give the raw data for this improved observability. How the
Automated driving of road vehicles needs to use a simulation environment to develop control programs. A vehicle dynamic simulation program was implemented into a computer system. It contains a vehicle dynamic model that models all essential parts of a
For decades, biometric technologies were primarily used in law enforcement applications. Currently, they are increasingly being required in multiple public and private sector applications worldwide to authenticate a person?s identity, secure national
CCQM-K13.1 is a Subsequent Key Comparison for Cadmium and Lead in Sediment conducted to provide the opportunity for two NMIs to demonstrate and document improvements in measurement capability achieved since the conduct of CCQM-K13, Amount content of
A Key Comparison (CCQM-K31) of the determination of arsenic in a marine shellfish (oyster tissue) was conducted under the auspices of the CCQM Inorganic Analysis Working Group as a follow-up to the CCQM-P11 Pilot Study. Arsenic was present at naturally
High resolution IR absorption spectra of supersonically cooled ethyl radicals (T rot19 K) have ben obtained in a slit supersonic jet discharge expansion, revealing first rotationally resolved data for CH stretch excitation of the methyl group. Three
A recent evaluation of the accuracy of National Physical Laboratory (NPL) primary frequency standard NPL CsF1 gives an overall frequency uncertainty of δŅ/Ņ 0 = 1 × 10 -15. This stated uncertainty includes a correction of a frequency bias of δŅ/Ņ 0 = 8 ×
Joseph Achkar, Andreas Bauch, R Dach, R Hlavac, Luca Lorini, Thomas E. Parker, G. Petit, Dirk Piester, P Uhrich, K Szymaniec
Istituto Elettrotecnico Nazionale Galileo Ferraris (IEN), National Institute of Standards and Technology (NIST), National Physical Laboratory (NPL), Laboratoire National de Metrologie et de Essais?Observatoire de Paris/Systemes de Reference Temps Espace
Seong-Eun Park, Nhan V. Nguyen, Joseph J. Kopanski, John S. Suehle, Eric M. Vogel
Two-dimensional (2-D) doping profiles of differently doped Si homostructures were investigated by scanning capacitance microscopy (SCM) and scanning Kelvin probe microscopy (SKPM). The calibrated doping concentration of the n-step Si layers was in the
The methods used to critically evaluate and compile the data on energy levels, wavelengths, and ionization potentials of multiply ionized tungsten and other ions and atoms are described. Some examples of the problem occurring in the process of data
This report covers the work conducted within the National Institute of Standards and Technology's Computer Security Division during the Fiscal Year 2005. It discusses all projects and programs within the Division, staff highlights, and publications. For