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The NBS large-area alpha-particle counting systems
alpha particle; large area; monitoring; proportional counting; radioactivity; standards.
Two alpha-particle counting systems for the measurement of large-area sources have been developed at the National Bureau of Standards. The systems and their characteristics are described. One system uses an internal-source proportional counter and...
Journal of Research of NIST and Predecessor Publications

The absolute isotopic composition and atomic weight of terrestrial nickel
absolute ratio; atomic weight; isotopic abundance; mass spectrometry; nickel; SRM 986; Standard Reference Materials; terrestrial samples
Twenty-nine samples of high-purity nickel metals, reagent salts and minerals, collected from worldwide sources, have been examined by high-precision isotope ratio mass spectrometry for their nickel isotopic composition. These materials were...
Journal of Research of NIST and Predecessor Publications

The fifth spectrum of praseodymium
Atomic energy levels; isoelectronic sequence; praseodymiun; rare earth; spectrum; sliding spark discharge lamp
Twelve spectral lines of quadruply-ionized praseodymium in the region 840 to 2250 are reported. Five terms (4f2F, 5d 2D, 6s 2S, 6p 2P, and 7s 2S) and the hyperfine splitting of the 6s 2S term are given. A calculation of the principal ionization...
Journal of Research of NIST and Predecessor Publications

On complementary polar conical sets
Cunjugate functions; convex cones; duality; linear programming; orthogonality; polarity
Tucker has formulated the Duality Theorem of Linear Programming in terms of orthogonality properties of a pair of complementary orthogonal linear manifolds with respect to the positive orthant. This theorem is generalized by substituting...
Journal of Research of NIST and Predecessor Publications

Louis Gilles of the Libbey-Owens-Ford Glass Company removes the air atmosphere surrounding the Declaration of Independence manuscript and replaces it with helium
Photographs; History; Metrology; Manuscripts; Conservation and restoration; Preservation and restoration; Laboratories
Tubes sealed in holes drilled through the lead strip in diagonally opposite corners of the Declaration of Independence enclosure served as inlet and outlet ports for the helium. The ports permitted the complete replacement of the air atmosphere...
Historic Images

Detection of deep levels in high power semiconductor materials and devices
Deep level measurements; defect distribution; power semiconductor materials; power thyristors; semiconductor measurements; thermally stimulated measurements.
TSM and other deep level measurement techniques are used to detect, characterize, and identify deep level defects which control lifetime and leakage in semiconductor devices. These measurements are performed on an apparatus which is capable of...
Journal of Research of NIST and Predecessor Publications

Tritium-labeled compounds. X. Isotope effects in the oxidation of aldoses-1-t with bromine
Tritium isotope effects have been used in bromine oxidation studies of aldoses to evaluate two reaction paths previously postulated by Isbell and Pigman, namely, direct oxidation and oxidation after anomerization. Because the former path involves a...
Journal of Research of NIST and Predecessor Publications

SRM 1970: succinonitrile triple-point standard - a temperature reference standard near 58.08 degrees C
SRM 1970; standard reference materials; succinonitrile; thermometry; temperature fixed point.
Triple-point-of succinonitrile cells have been tested and established as Standard Reference Material (SRM) 1970. Of the 115 cells tested, 109 were accepted as SRM 1970. Five of the 115 cells had triple-point temperatures lower than 58.0785 degrees...
Journal of Research of NIST and Predecessor Publications

Sources of uncertainty in a DVM-based measurement system for a quantized Hall resistance standard
digital voltmeter; DVM method; electrical metrology; electrical reference standards; quantized hall resistance; quantum hall effect; resistance calibration
Transportable 10 kOMEGA standard resistors have become fairly widespread in industrial, university, and government standards laboratories because of their low temperature coefficient of resistance, ease of transportation, and convenient value. The...
Journal of Research of NIST and Predecessor Publications

Arc measurement of some argon transition probabilities
Arc; argon; linewidth; plasma; spectroscopy; stark broadening; transition probability
Transition probabilities and line shape parameters for three argon lines have been measured in a wall-stabilized argon arc containing a trace of hydrogen. The Hß line shape measurement and the assumption of local thermodynamic equilibrium provided...
Journal of Research of NIST and Predecessor Publications

Tropospheric scatter propagation and atmospheric circulations
Transhorizon vhf and uhf fields exhibit deep fades or large signal enhancements of several hours' duration, as the propagation mechanism alternates between partial reflection and scattering caused by turbulent dielectric fluctuations in the...
Journal of Research of NIST and Predecessor Publications

Workshop on Lunar Calibration for Satellite Remote Sensing
calibration; lunar spectral irradiance; moon; radiometry; remote sensing.
Tracking climate variables at the levels of precision and accuracy required to detect global change requires satellite sensors to make highly consistent measurements that can be compared to measurements made at different times and with different...
Journal of Research of NIST and Predecessor Publications

THE COLLECTION AND PREPARATION OF HUMAN-BLOOD PLASMA OR SERUM FOR TRACE-ELEMENT ANALYSIS
blood collection devices; clean room conditions; high-purity reagents; sample containers; sample contamination.
Trace element concentrations in blood plasma or serum have been assayed by numerous investigators using a variety of analytical techniques. For several elements, figures obtained in different centers are widely disparate. Impressive evidence has...
Journal of Research of NIST and Predecessor Publications

Average annual expenditures and earnings from 1910-1919 for group II - research, education, and development
Photographs; History; Metrology; Expenditures, Public
Total area of each sector represents gross disbursement; black area represents receipts; white area represents net expenditure. Answering the charge of extravagance in Federal spending, Dr. Edward B. Rosa (Chief Physicist, NBS) showed that in the...
Historic Images

Synthetic Incoherence via Scanned Gaussian Beams
electron microscopy; Gaussian beams; incoherence; synthetic incoherence
Tomography, in most formulations, requires an incoherent signal. For a conventional transmission electron microscope, the coherence of the beam often results in diffraction effects that limit the ability to perform a 3D reconstruction from a tilt...
Journal of Research of NIST and Predecessor Publications

Tom Lucatorto, Charles Clark, David Ederer, Bob Madden
Photographs; History; Metrology; Physics; Physicists
Tom Lucatorto, Charles Clark, David Ederer, Bob Madden This image is part of the Physics Division collection and contains photographs of Physics Division facilities, staff, and events.
NBS-NIST Divisions, Offices, and Programs

Algorithms for scanned probe microscope image simulation, surface reconstruction, and tip estimation
algorithms; atomic force microscopy; blind reconstruction; dimensional metrology; image simulation; mathematical morphology; scanned probe microscopy; scanning tunneling microscopy; surface reconstruction; tip artifacts; tip estimation
To the extent that tips are not perfectly sharp, images produced by scanned probe microscopies (SPM) such as atomic force microscopy and scanning tunneling microscopy are only approximations of the specimen surface, np-induced distortions are...
Journal of Research of NIST and Predecessor Publications

A Pienkowsky-type calibration scheme for 5211S1 weight series using two knife-edge direct-reading balances
To supplement information given in an earlier paper (J. Res. NBS 66C (Eng. and Instr.) No. 1, 33 (1962)) a Pienkowsky-type series is presented for the calibration of a set of weights having a combined mass of 10 units and individual masses of 5, 2,...
Journal of Research of NIST and Predecessor Publications

Optical characterization in microelectronics manufacturing
ellipsometry; infrared spectroscopy; modulation spectroscopy; optical microscopy; photoluminescence; Raman scattering
To successfully construct semiconductor devices, the semiconductor industry must measure fundamental material parameters, especially when developing new materials; measure the quality of the material as it is grown; accurately determine the details...
Journal of Research of NIST and Predecessor Publications

Leather specimens in oven to study fungicides
Shoes; Materials; Testing; Leather; Research; Photographs; History; Metrology; 1950s; Laboratories
To simulate a tropical environment, the treated specimens of leather are kept in an oven at 30 degrees Celsius. A small amount of water in the bottom of each specimen jar provides the necessary humidity. This image is part of the Leather Research...
Historic Images

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