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Displaying 26576 - 26600 of 73832

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

Multi-Scale Pore Morphology in Vapor-Deposited Yttria-Stabilized Zirconia Coatings

June 16, 2010
Author(s)
Derek D. Hass, H. Zhao, Tabbetha A. Dobbins, Andrew J. Allen, Andrew Slifka, H. N. Wadley
A high pressure, electron-beam directed-vapor deposition process has been used to deposit partially stabilized zirconia containing 7 % yttria by mass at deposition pressures of 7.5 Pa to 23 Pa. Anisotropic ultra-small-angle X-ray scattering (USAXS) was

Representing Egress Behaviour in Engineering Terms

June 16, 2010
Author(s)
Steve M. Gwynne, Erica D. Kuligowski, Daniel Nilsson
When using engineering tools to calculate RSET, the engineer must have sufficient expertise to identify actual human factors that will influence the outcome of an evacuation in a particular situation. The engineer must then represent these factors in the

Testing Interoperability Standards - A Test Case Generation Methodology

June 16, 2010
Author(s)
Nenad Ivezic, Jungyub Woo
Over many years, National Institute of Standards and Technology (NIST) built test beds to support interoperability standards development and their implementation within software applications. A general test framework has been proposed to enhance new test

Tooth chipping can reveal bite forces and diets of fossil hominins

June 16, 2010
Author(s)
Paul Constantino, James J. Lee, H Chai, Bernhard Zipfel, Charles Ziscovici, Brian R. Lawn, Peter Lucas
Fossil hominin tooth enamel often exhibits antemortem edge chipping (Robinson 1954; Tobias 1967; Wallace 1973). Here we apply a simple fracture equation to estimate peak bite forces from the sizes of such chips. This equation, previously validated by

Cd-doping effects in Ce 2 MIn 8 (M=Rh and Ir) Heavy Fermion Compounds

June 15, 2010
Author(s)
C. Adriano, C. Giles, E. M. Bittar, L. N. Coelho, F. de Bergevin, C. Mazzoli, L. Paolasini, William Ratcliff, Richard Bindel, Jeffrey Lynn, Z. Fisk, P. G. Pagliuso
Low temperature magnetic properties of Cd-doped Ce 2MIn 8 (M = Rh and Ir) single crystals are investigated. Experiments of temperature dependent magnetic susceptibility, heat capacity and electrical resistivity measurements revealed that Cd-doping enhances

Controlling High Coercivities of Ferromagnetic Nanowires Encapsulated in Carbon Nanotubes

June 15, 2010
Author(s)
Robert D. Shull, Cindi L. Dennis, A. Morelos-Gomez, Florentino N. Lopez-Urias, Emilio N. Munoz-Sandoval, H. Terrones, M. Terrones
Cylindrical ferromagnetic nanowires encapsulated inside multiwalled carbon nanotubes (MWNTs) are synthesized by pyrolizing either ferrocene powder or ferrocene-toluene mixtures. By changing the way the precursor is thermolyzed, we have been able to control
Displaying 26576 - 26600 of 73832
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