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Displaying 40826 - 40850 of 74225

Some Issues Relating to Performance Evaluation of LADARs

September 16, 2003
Author(s)
Geraldine S. Cheok, William C. Stone, Christoph J. Witzgall
The use and scope of LADAR applications continues to expand as the technology matures. This growth is reflected in NIST's experience with research into the applications of LADARs for construction, manufacturing, and autonomous vehicle navigation. However

Terrain Characterization from Ground-Based LADAR

September 16, 2003
Author(s)
Christoph J. Witzgall, Geraldine Cheok, David E. Gilsinn
Test runs of Army Research Laboratory s (ARL) autonomous vehicle (Experimental Unmanned Vehicle, XUV) were followed by the acquisition of high resolution scans of selected regions of the test course. These scans were used to i) determine terrain features

Kinetic Isotope Effects in the Active Site of B-Subtilis Chorismate Mutase

September 15, 2003
Author(s)
S. E. Worthington, A. E. Roitberg, Morris Krauss
Kinetic Isotope Effects are determined for the enzyme-catalyzed Claisen rearrangement of chorismate to prephenate using computational methods. The reported kinetic isotope effects compare reasonably well with the few available experimental values. The

The Refprop Database for the Thermophysical Properties of Refrigerants

September 14, 2003
Author(s)
Mark O. McLinden, Eric W. Lemmon, Marcia L. Huber
Property databases are widely used for the design and analysis of refrigeration systems. Version 7 of the NIST REFPROP Reference Fluid Thermodynamic and Transport Properties) database is described. Compared with previous versions, the database includes

Interdiffision in Polystyrene and End-Functional Polystyrene Thin Films Near a Solid Surface

September 10, 2003
Author(s)
Chengqing C. Wang, Vivek M. Prabhu, Christopher L. Soles, B D. Vogt, Wen-Li Wu, Eric K. Lin, Sushil K. Satija
Polymer interdiffusion near the polymer/solid interface is studied using neutron reflectometry. Bilayers of hydrogenated polystyrene (hPS) and deuterated polystyrene (dPS) or hydrogenated dicarboxy terminated polystyrene (hPS(COOH)2) and dPS are prepared

High-Frequency Characteristics of Metal/Native-Oxide Multilayers

September 5, 2003
Author(s)
Geoffrey S. Beach, Thomas J. Silva, F. T. Parker, A. E. Berkowitz
The high-frequency magnetization dynamics of magnetically soft Co χFe 100-χ metal/native-oxide multilayers were studied as a function of alloy composition (10 less than or equal to} χ less than or equal to} 50) using a time-domain inductive technique. The

Large-Scale Modeling of Fire Suppression with Water Sprays

September 2, 2003
Author(s)
Kevin B. McGrattan
The mechanisms underlying fire suppression by water can bedivided into gas and solid phase phenomena. Numerical models ofthese phenomena are dependent on the level of detail given to thecombustion and the fuel pyrolysis processes.Presently, models of gas

Unwanted Accelerated Burning After Suppressant Delivery

September 2, 2003
Author(s)
Anthony P. Hamins, Kevin B. McGrattan, Glenn P. Forney
In a number of real-scale fire tests, accelerated or enhanced unwanted burning has been observed immediately following the delivery of a fire suppressant. The conditions under which this phenomena occurs, its potential for harm, and its effect on the

3-Dimensional Lineshape Metrology Using Small Angle X-ray Scattering

September 1, 2003
Author(s)
Ronald L. Jones, T J. Hu, Eric K. Lin, Wen-Li Wu, D M. Casa, G G. Barclay
The need for sub-nanometer precision metrology of dense patterns for future technology nodes challenges current methods based on light scatterometry, scanning electron microscopy (SEM), and atomic force microscopy (AFM). We provide results of initial tests

40 Years of Metrology With Synchrotron Radiation at SURF

September 1, 2003
Author(s)
Uwe Arp, Steven E. Grantham, Simon G. Kaplan, Ping-Shine Shaw, Charles S. Tarrio, Robert E. Vest
the advantages of a compact synchrotron radiation source like the Synchrotron Ultraviolet Radiation Facility for metrology in the ultraviolet and extreme ultraviolet are shown. The capabilities of the different experimental stations are explained and

A Direct Comparison of Surface and Bulk Chain-Relaxation in Polystyrene

September 1, 2003
Author(s)
Wen-Li Wu, S Sambasivan, C M. Wang, William E. Wallace, Jan Genzer, Daniel A. Fischer
Near-edge x-ray absorption fine structure (NEXAFS) spectroscopy was used to meausre simultaneously the relaxation rates of polystyrene (PS) molecules at the free surface and in the bulk. The samples were uniaxially stretched and annealed at temperatures

A Four-Zone Furnace for Realization of Silver and Gold Freezing Points

September 1, 2003
Author(s)
Dean C. Ripple, K Garrity, Christopher W. Meyer
Recently, the Thermocouple Calibration Laboratory at the National Institute of Standards and Technology has used sodium heat-pipe furnaces for the realization of ITS-90 freezing points of aluminum, silver, and gold. When using a fixed-point cell mounted in

Abrasive Machining of Porcelain and Zirconia With a Dental Handpiece

September 1, 2003
Author(s)
L Yin, S Jahanmir, L K. Ives
The machining characteristics and material removal mechanisms of two dental ceramics feldspathic porcelain and yttria-stabilized tetragonal zirconia - were investigated using a dental handpiece and diamond burs with different grit sizes. The material

Active millimeter-wave imaging for concealed weapons detection

September 1, 2003
Author(s)
Erich N. Grossman, Aaron J. Miller
Actively illuminated mm-wave imaging systems for concealed weapons detection offer the possibility of much higher sensitivity than with passive systems. We discuss several issues specific to mm-wave imaging systems that are actively illuminated and

An Open Standard for Chemical Structure Representation: The IUPAC Chemical Identifier

September 1, 2003
Author(s)
Stephen E. Stein, Stephen R. Heller, Dmitrii V. Tchekhovskoi
IUPAC has long been involved in the development of systematic and standard procedures for naming chemical substances on the basis of their structure. The resulting rules of nomenclature, while covering almost all compounds, were designed for text-based

Basic Mass Metrology

September 1, 2003
Author(s)
Georgia L. Harris
Basic Mass Metrology CD-ROM training course. Course is designed to run after the CD is inserted in a Windows-based computer.

Bevel Depth Profiling SIMS for Analysis of Layer Structures

September 1, 2003
Author(s)
John G. Gillen, Scott A. Wight, P Chi, Albert J. Fahey, Jennifer R. Verkouteren, Eric S. Windsor, D. B. Fenner
We are evaluating the use of bevel depth profiling Secondary Ion Mass Spectrometry (SIMS) for the characterization of layered semiconductor materials. In this procedure, a sub-degree angle bevel is cut into the analytical sample with an oxygen or cesium

Cable-Based Metrology System for Sculpting Assistance

September 1, 2003
Author(s)
R L. Williams, James S. Albus, Roger V. Bostelman
ABSTRACT A novel cable-based metrology system is presented wherein six cables are connected in parallel from ground-mounted string pots to the moving object of interest. Cartesian pose can be determined for feedback control and other purposes by reading
Displaying 40826 - 40850 of 74225
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