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Displaying 2051 - 2075 of 2608

Towards a Traceable Nanoscale Force Standard

May 1, 2001
Author(s)
Jon R. Pratt, David B. Newell, Edwin R. Williams, Douglas T. Smith, John A. Kramar
The National Institute of Standards and Technology has launched a five-year project to traceably link the International System of Units (SI) to forces between 10 -8N and 10 -2N. In this paper, we give a background and overview of this project, discuss the

Flow Measurement Proficiency Testing

April 1, 2001
Author(s)
G E. Mattingly
To eliminate measurement-base trade barriers to international commerce, Key Comparisons (KCS) are now being planned in the newly formed Working Group for Fluid Flow (WGFF) in the CIPM to quantify the equivalency of the flow standards maintained in the

A Careful Consideration of the Calibration Concept

March 1, 2001
Author(s)
Steven D. Phillips, William T. Estler, Theodore D. Doiron, K Eberhardt, M Levenson
This paper is a detailed discussion of the technical aspects of the calibration process with emphasis on the definition of the measurand, the conditions under which the calibration results are valid, and the subsequent use of the calibration results in

Shape-Sensitive Linewidth Measurement with the SEM Using a Model-Based Library

March 1, 2001
Author(s)
John S. Villarrubia, Andras Vladar, J R. Lowney, Michael T. Postek
In semiconductor electronics manufacturing, device performance often depends upon size. For example, microprocessor speed is linked to the width of transistor gates. Accurate measurement of feature width is an important but challenging problem. When a

Index of Refraction of Air

February 16, 2001
Author(s)
Jack A. Stone Jr., Jay H. Zimmerman
These Web pages are intended primarily as a computational tool that can be used to calculate the refractive index of air for a given wavelength of light and given atmospheric conditions (air temperature, pressure, and humidity). The calculations are

Documentary and Physical Standards for Surface Finish and Imperfections

February 1, 2001
Author(s)
Theodore V. Vorburger
Surface finish and imperfections are important properties of optical surfaces because they are caused by manufacturing limitations or defects and are linked to degradation of optical performance. Surface finish or surface roughness constitutes the numerous

Laminar Flow of Four Gases Through a Helical Rectangular Duct

February 1, 2001
Author(s)
Robert F. Berg, S A. Tison
We report measurements and a model of gas flow through a helical duct of rectangular cross section. The measurements on helium, nitrogen, argon, and sulfur hexafluoride yielded molar flow rates from observations of the rate of rise of pressure in a known

Length and Dimensional Measurements at NIST

February 1, 2001
Author(s)
Dennis A. Swyt
This paper reports on the past, present, and future of length and dimensional measurements at NIST. It covers the evolution of the SI unit of length through its three definitions and the evolution of NBS-NIST dimensional measurement from early linescales

A Careful Consideration of the Calibration Concept

January 1, 2001
Author(s)
Steven D. Phillips, William T. Estler, Theodore D. Doiron, K Eberhardt, M. Levenson
This paper is a detailed discussion of the technical aspects of the calibration process with emphasis on the definition of the measurand, the conditions under which the calibration results are valid, and the subsequent use of the calibration results in

A Novel Artifact for Testing Large Coordinate Measuring Machines

January 1, 2001
Author(s)
Steven D. Phillips, Daniel S. Sawyer, Bruce R. Borchardt, D E. Ward, D E. Beutel
We present a high accuracy artifact useful for the evaluation of large CMMs. This artifact can be physically probed by the CMM in contrast to conventional techniques that use purely optical methods such as laser interferometers. The system can be used over

Atomic Level Surface Metrology

January 1, 2001
Author(s)
Theodore V. Vorburger, Ronald G. Dixson, Jun-Feng Song, Thomas Brian Renegar, Joseph Fu, Ndubuisi George Orji, V W. Tsai, E. C. Williams, H Edwards, D Cook, P West, R Nyffenegger
MotivationSemiconductor wafers and many types of optical elementsrequire ultra-smooth surfaces in order to functionas specifiedExamples:Laser gyro mirrors with rms roughness 0.1 nmSilicon gate oxides with thickness 3 nm,rms roughness must be significantly

Chapter 12: Analysis of Individual Collected Particles

January 1, 2001
Author(s)
Robert A. Fletcher, John A. Small, J H. Scott
This chapter describes microscopes and microprobes used for analysis of collected, individual particles. The instruments discussed are the light microscope, electron microscopes (scanning, environmental and transmission), electron microprobes, laser

Effect of Aluminum Flake Orientation on Coating Appearance

January 1, 2001
Author(s)
L Sung, Maria Nadal, M E. McKnight, Egon Marx, R Dutruc, B Laurenti
The orientation of platelet-like pigments in coatings is affected by the processing conditions resulting in appearance variations of the final product. A set of aluminum-flake pigmented coatings having different flake orientations was pre-pared using

Establishment of a Virtual / Physical Standard for Bullet Signature Measurements

January 1, 2001
Author(s)
Jun-Feng Song, Theodore V. Vorburger, M Ols
The National Integrated Ballistics Information Network (NIBIN) is currently under development by the Bureau of Alcohol, Tobacco and Firearms (ATF) and the Federal Bureau of Investigation (FBI). The National Institute of Standards and Technology (NIST) and
Displaying 2051 - 2075 of 2608