U.S. flag

An official website of the United States government

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.

Search Publications

NIST Authors in Bold

Displaying 26651 - 26675 of 73929

Bit Error Rate Measurements in Reverberation Chambers using a VSA

June 21, 2010
Author(s)
Catherine A. Remley, Sander Floris, Christopher L. Holloway
We discuss practical measurement implementation issues regarding the use of a vector signal analyzer for making bit-error-rate measurements in reverberation chambers. These issues include synchronizing the transmitted and received signals in spite of time

Reverberation-Chamber Test Environment for Outdoor Urban Wireless Propagation Studies

June 21, 2010
Author(s)
Helge Fielitz, Kate Remley, Christopher L. Holloway, Qian Zhang, Qiong Wu, David W. Matolak
We introduce a test environment to replicate the well-known clustering of reflections in power delay profiles from urban wireless propagation environments that exhibit late-time delays and reflections. The test set-up combines discrete reflections

Visual Similarity based 3D Shape Retrieval Using Bag-of-Features

June 21, 2010
Author(s)
Zhouhui Lian, Afzal A. Godil, Xianfang Sun
This paper develops a novel 3D shape retrieval method, which uses Bag-of-Features and an efficient multi-view shape matching scheme. In our approach, a properly normalized object is first described by a set of depth-buffer views captured on the surrounding

Application of Microwave Scanning Probes to Photovoltaic Materials

June 20, 2010
Author(s)
Kristine A. Bertness, John B. Schlager, Norman A. Sanford, Atif A. Imtiaz, Thomas M. Wallis, Joel C. Weber, Pavel Kabos, Lorelle M. Mansfield
We demonstrate that near field scanning microwave microscopy (NSMM) can be used to detect photoresponse in photovoltaic materials with potential for submicrometer resolution. In this approach, a radio-frequency scanning tunneling microscopy (RF-STM) tip is

Method to determine the absorbance of thin films for photovoltaic technology

June 20, 2010
Author(s)
Nathan A. Tomlin, John H. Lehman, Katherine E. Hurst, D. B. Tanner, K. Kamaras, Aron Pekker
We have demonstrated a novel method to determine optical properties of opaque or semi-transparent films for photovoltaic (PV) applications. Such films may be the basis of transparent conductors or photoconductive material. As an example, we measure the

Quartz Crystal Microbalances for Microscale Thermogravimetric Analysis

June 20, 2010
Author(s)
Elisabeth Mansfield, Aparna Kar, Stephanie A. Hooker
A new method for analyzing the chemical purity and consistency of microscale samples is described using a quartz crystal microbalance (QCM) sensor platform. The QCM is used to monitor sub-picogram changes in the mass of a deposited thin film as a function

Space charge limited current effects in silicon at high injection levels

June 20, 2010
Author(s)
Ari D. Feldman, Richard K. Ahrenkiel
The space charge limited current (SCLC) effect will be analyzed in undoped crystalline silicon wafers at high injection levels. Space charge limited currents develop when the electric field from the injected carriers exceeds that of the background doping

Behavior of e (omega} and tan d of a Class of Low-Loss Materials

June 18, 2010
Author(s)
James R. Baker-Jarvis, Michael D. Janezic, Billy F. Riddle, Kim Sung
In this project we study the behavior of the permittivity and loss tangent of a class of materials that exhibit relaxation. For relaxation response we show that the permittivity is a monotonically decreasing function of frequency. Also, for many low-liss

On interchangeability of two laboratories

June 18, 2010
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
This paper proposes a measure for assessing the degree of equivalence between the two laboratories in a key comparison. The measure is called asymmetric degree of interchangeability. It is asymmetric since, based on this measure, a laboratory may be

Simulator for Amplifier and Transistor Noise-Parameter Measurements

June 18, 2010
Author(s)
James P. Randa
This paper describes a simulation program that was developed to compare the uncertainties that would be expected with different measurement strategies for the noise parameters of connectorized amplifiers and of amplifiers or transistors on wafers. Both

Report on the Evaluation of 2D Still-Image Face Recognition Algorithms

June 17, 2010
Author(s)
Patrick J. Grother, George W. Quinn, P J. Phillips
The paper evaluates state-of-the-art face identification and verification algorithms, by applying them to corpora of face images the population of which extends into the millions. Performance is stated in terms of core accuracy and speed metrics, and the

Safely mounting glass viewports to elastomer sealed vacuum flanges

June 17, 2010
Author(s)
Patrick J. Abbott, Brian R. Scace
Elastomer sealed vacuum flanges rely on specially sized elastomer O-rings and corresponding grooves to make an air-tight seal. Depending on the materials being sealed to one another, the O-ring/groove sealing mechanism may be designed for a specific

Complex Systems Collected Images of the Month March 2008 - June 2010

June 16, 2010
Author(s)
Sanford P. Ressler
This document is a collection of twenty eight Complex Systems Image of the Month (IOM) illustrations. Each month as part of the Complex Systems Program in the Information Technology Laboratory an IOM is produced, posted to the Complex Systems web site and

Global analysis of Forster resonance energy transfer in live cells measured by fluorescence lifetime imaging microscopy exploiting the rise time of acceptor fluorescence

June 16, 2010
Author(s)
Katharine M. Mullen, Sergey Laptenok, Jan Willem , Antonie Visser, Ivo van Stokkum
A methodology is described for the detection of F rster Resonance Energy Transfer (FRET) in live cells by monitoring the rise time of the acceptor fluorescence using fluorescence lifetime imaging microscopy (FLIM). An advantage of this method is that only

High frequency characterization of a Schottky contact to a GaN nanowire bundle

June 16, 2010
Author(s)
Chin J. Chiang, Thomas M. Wallis, Dazhen Gu, Atif A. Imtiaz, Pavel Kabos, Paul T. Blanchard, Kristine A. Bertness, Norman A. Sanford, Kichul Kim, Dejan Filipovic
A GaN nanowire (NW) Schottky contact was characterized up to 10 GHz. Using a calibration procedure and circuit model a capacitance-voltage (CV) curve was obtained, from which a carrier concentration was calculated for the first time. These results
Displaying 26651 - 26675 of 73929
Was this page helpful?