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Displaying 28726 - 28750 of 74220

A New Chemical Reactor for Protein Crystal Growth

October 16, 2008
Author(s)
David Travis Gallagher, C Stover, J Moses, D Charlton, E Steinberg, L Arnowitz
Current rapid advances in the genomic and biochemical sciences provide impetus for finding improved ways of crystallizing proteins for structure determination. A new dialysis-based reactor for protein crystal growth is described. The device utilizes motor

A New International Evaluation of the Neutron Cross Section Standards

October 16, 2008
Author(s)
Allan D. Carlson
The measurements of most neutron cross sections are made relative to neutron cross section standards. The last complete evaluation ofthe standards, which was for ENDF/B-VI, took place almost 15 years ago. The cross section standards produced for the ENDF/B

A Standard Reporting Format for Summative Usability Evalutations

October 16, 2008
Author(s)
Jean C. Scholtz, Emile L. Morse
Poor usability is an uncontrolled source of overhead, caused by the need for users to correct errors and continually re-learn complex user interfaces. Software that is measurably usable reduces errors, reduces training costs, and reduces maintenance costs

A Statistical Connection Between Dislocations and Mechanical Properties

October 16, 2008
Author(s)
Lyle E. Levine, R M. Thomson
The extreme complexity of the dislocation-based processes that underlie plastic deformation are in marked contrast to the relatively simple behavior observed macroscopically. The simplification arises because a deforming metal can be described as a self

A Systematically-Generated, Pressure-Dependent Mechanism for High-Conversion Ethane Pyrolysis. Part II: Radical Disproportionations, Missing Reaction Families, and the Consequences of Pressure-Dependence

October 16, 2008
Author(s)
D M. Matheu, J M. Grenda
Part I of this work systematically developed a pressure-dependent reaction mechanism for the high-conversion pyrolysis of ethane [1], as studied experimentally by Glasier and Pacey [2]. By combining conventional equilibrium, sensitivity, and reaction

Accoustic Studies of Composite-Material Interfaces

October 16, 2008
Author(s)
H M. Ledbetter
We review six recent acoustic studies of composite-material interfaces. Measured physical properties are either elastic constants (sound velocities resonance frequencies) or internal frictions. The materials considered include (1) glass fiber/epoxy, (2)

Accuracy Issues in Chemical and Dimensional Metrology in the SEM and TEM

October 16, 2008
Author(s)
J H. Scott
In this work computer simulations are used to understand systematic errors and accuracy concerns in both dimensional and chemical metrology in the scanning electron microscope (SEM) and transmission electron microscope (TEM).Multislice high-resolution TEM

Accurate Determination of High Energy Gamma-Ray Standards

October 16, 2008
Author(s)
Ernest G. Kessler Jr., Maynard S. Dewey, R Deslattes, Albert Henins, H G. Borner, M Jentschel, H Lehmann
The extension of accurate crystal diffraction spectroscopy to the 2 to 6 MeV region is described. Gamma-ray standards with a relative uncertainty of (2 to 5)x10 -7 are obtained by measuring the small diffraction angles (a few tenths of a degree) through

AFM Observations of Slip Band Development in AI Single Crystals

October 16, 2008
Author(s)
D E. Kramer, M Savage, Lyle E. Levine
In situ atomic force microscopy (AFM) is used to observe the structure and evolution of slip bands on the surface of plastically deformed aluminum single crystals. Both the structure and evolution of the slip bands are observed to be a function of the

Alloy Selection

October 16, 2008
Author(s)
C A. Handwerker, Ursula R. Kattner, Kil-Won Moon, J Bath, E -. Bradley, P Snugovsky
In this chapter, the key results and analyses leading to the choice of tin-silver-copper alloys by NEMI as the new national standard Pb-free solder system are discussed in detail. These include data on phase transformations in solders (including melting

Amphiphilic Block Copolymer Nanotubes and Vesicles Stabilized byPhotopolymerization

October 16, 2008
Author(s)
Ana Jofre, John B. Hutchison, Laurie E. Locascio, Kristian Helmerson
Photopolymerization is implemented to crosslink and stabilize vesicles and nanotubes composed of amphiphilic block copolymer chains. Stabilized membranes of nanotubes and vesicles were formed by the directed self-assembly of poly(ethylene oxide)-block

An Approach for Assessing Total Cellular DNA Damage

October 16, 2008
Author(s)
Marc Roy
The capability to relate phenotypic effects with damage associated with either of the two genomes is especially useful under a number of circumstances. Potential hazardous exposures (e.g. smoking, pesticides, uv-light) can be evaluated for genotoxicity and
Displaying 28726 - 28750 of 74220