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Preparation of multilayered materials in cross-section for in situ TEM tensile deformation studies

Description: The success of in-situ transmission electron microscopy experimentation is often dictated by proper specimen preparation. We report here a novel technique permitting the production of cross-sectioned tensile specimens of multilayered films for in-situ deformation studies. Of primary importance in the development of this technique is the production of an electron transparent micro-gauge section using focused ion beam technology. This microgauge section predetermines the position at which plastic… more
Date: May 13, 1997
Creator: Wall, M. A.
Partner: UNT Libraries Government Documents Department
open access

Periodic arrays of pinning centers in thin vanadium films.

Description: Commensurability effects between the superconducting flux line lattice and a square lattice (period d=1{micro}m and diameter D=0.4{micro}m) of submicron holes in 1500 {angstrom} vanadium films were studied by atomic force microscopy, DC magnetization, AC susceptibility, magnetoresistivity and I-V measurements. Peaks in the magnetization and critical current at matching fields are found to depend nonlinearly upon the value of external AC field or current, as well as the inferred symmetry of the … more
Date: July 13, 1997
Creator: Brueck, S. R. J.; Chung, K.; Crabtree, G.; DeLong, L. E.; Hesketh, P. J.; Ilic, B. et al.
Partner: UNT Libraries Government Documents Department
open access

Search for Nuclei Containing Two Strange Quarks

Description: This paper discusses a search for nuclei containing two strange quarks performed at Brookhaven National Laboratory. The goals and approach of experiment E885 are reviewed. Preliminary missing mass spectra for a subset of the data are presented, showing sensitivity for {Xi} hypernuclei and H particle searches. Existence of an angular correlation between pions in the sequential decay of {Lambda}{Lambda} hypernuclei is suggested on theoretical grounds.
Date: October 13, 1997
Creator: May, M.
Partner: UNT Libraries Government Documents Department
open access

Epimorphin Functions as a Key Morphoregulator for Mammary Epithelial Cells

Description: Hepatocyte growth factor (HGF) and EGF have been reported to promote branching morphogenesis of mammary epithelial cells. We now show that it is epimorphin that is primarily responsible for this phenomenon. In vivo, epimorphin was detected in the stromal compartment but not in lumenal epithelial cells of the mammary gland; in culture, however, a subpopulation of mammary epithelial cells produced significant amounts of epimorphin. When epimorphin-expressing epithelial cell clones were cultured i… more
Date: October 13, 1997
Creator: Hirai, H.; Lochter, A.; Galosy, S.; Koshida, S.; Niwa, S. & Bissell, M.J.
Partner: UNT Libraries Government Documents Department
open access

Density of topological defects after a quench

Description: We present results of numerical studies of the Landau-Ginzburg dynamics of the order parameter in one-dimensional models inspired by the condensed matter analogues of cosmological phase transitions. The main goal of our work is to show that, as proposed by one of us, the density of the frozen-out topological defects is set by the competition between the quench rate - the rate at which the phase transition is taking place - and the relaxation rate of the order parameter. In other words, the char… more
Date: May 13, 1997
Creator: Laguna, P. & Zurek, W.H.
Partner: UNT Libraries Government Documents Department
open access

A 3-dimensional ray-trace model for predicting the performance of flashlamp-pumped laser amplifiers

Description: We have developed a fully three-dimensional model for the performance of flashlamp pumped laser amplifiers. The model uses a reverse ray-trace technique to calculate the pumping of the laser glass by the flashlamp radiation. We have discovered several different methods by which we can speed up the calculation of the gain profile in a amplifier. The model predicts the energy-storage performance of the Beamlet amplifiers to better than 5%. This model will be used in the optimization of the Nation… more
Date: February 13, 1997
Creator: Jancaitis, K.S.; Haney, S.W.; Munro, D.H.; Le Touze, G. & Cabourdin, O.
Partner: UNT Libraries Government Documents Department
open access

Impurity and laser-induced damage in the growth sectors of rapidly grown DKP crystals

Description: We report the experimental results of impurity contamination and laser-induced damage investigations on rapidly grown potassium dihydrogen phosphate (KDP) crystals. Using absorption spectroscopy and chemical analysis, we determined the impurity distribution in the different growing sectors of KDP single crystals. The level of impurity was dependent on starting materials and growth rate. We also studied influence of impurities on laser-induced damage in fast grown KDP. The laser damage threshold… more
Date: February 13, 1997
Creator: Yan, M.; Torres, R.; Runkel, M.; Woods, B.; Hutcheon, I.; Zaitseva, N. et al.
Partner: UNT Libraries Government Documents Department
open access

Three dimensional high-resolution simulations of richtmyer-meshkov mixing and shock-turbulence interaction

Description: Three-dimensional high-resolution simulations are performed of the Richtmyer- Meshkov (RM) instability for a Mach 6 shock, and of the passage of a second shock from the same side through a developed RM instability. The second shock is found to rapidly smear fine structure and strongly enhance mixing. Studies of the interaction of moderately strong shocks with a pre-existing turbulent field indicate amplification of transverse vorticity and reduction Of stream-wise vorticity, as well as the mech… more
Date: June 13, 1997
Creator: Cohen, R. H.; Dannevik, W. P.; Dinits, A.; Miason, D.; Mirin, A. A.; Portor, D. H. et al.
Partner: UNT Libraries Government Documents Department
open access

Anomalous gauge boson couplings

Description: The measurement of anomalous gauge boson self couplings is reviewed for a variety of present and planned accelerators. Sensitivities are compared for these accelerators using models based on the effective Lagrangian approach. The sensitivities described here are for measurement of {open_quotes}generic{close_quotes} parameters {kappa}{sub V}, {lambda}{sub V}, etc., defined in the text. Pre-LHC measurements will not probe these coupling parameters to precision better than O(10{sup -1}). The LHC s… more
Date: January 13, 1997
Creator: Barklow, T.; Rizzo, T. & Baur, U.
Partner: UNT Libraries Government Documents Department
open access

Use of the Pegasus Z pinch machine to study inertial instabilities in aluminum: a preliminary report

Description: We have designed a target to probe the use of the Pegasus Z-Pinch machine to image inertial instabilities that develop on cylindrical- convergent material interfaces. The Z-pinch is tailored so that the target, soft Al 1100-O, remains solid; instabilities and inertial effects are seeded by wire inclusions of different densities. We present here the first images and preliminary results from this experiment.
Date: June 13, 1997
Creator: Chandler, E.; Egan, P.; Winer, K.; Stokes, J.; Fulton, R. D.; King, N. S. P. et al.
Partner: UNT Libraries Government Documents Department
open access

Susy and Such

Description: In these lectures, the author discusses the theoretical motivation for supersymmetric theories and introduce the minimal low energy effective supersymmetric theory, (MSSM). I consider only the MSSM and its simplest grand unified extension here. Some of the other possible low-energy SUSY models are summarized. The particles and their interactions are examined in detail in the next sections and a grand unified SUSY model presented which gives additional motivation for pursuing supersymmetric theo… more
Date: January 13, 1997
Creator: Dawson, S.
Partner: UNT Libraries Government Documents Department
open access

Microstructure of bulk and electro-formed Ni implanted with Ti and C

Description: The microstructure of high-purity Ni implanted with overlapping concentration profiles of Ti and C was examined with transmission electron microscopy. An amorphous phase forms at concentrations of 15--18 at.% Ti and 22 at.% C, while a two-phase alloy (amorphous + fcc Ni) forms for {le} 16 at.% C. Electroformed layers with sub-micron fcc grains of Ni or Ni{sub 80}Fe{sub 20} were also found to be amorphized by Ti + C implantation, a key requirement for applying this treatment to Ni-based micro-el… more
Date: October 13, 1997
Creator: Follstaedt, D. M.; Myers, S. M.; Knapp, J. A.; Dugger, M. T. & Christenson, T. A.
Partner: UNT Libraries Government Documents Department
open access

Rapid growth of large-scale (40-55 cm) KDP crystals

Description: KDP (KH{sub 2}PO{sub 4}) single crystals up to 47 cm in size have been grown by the rapid growth technique on the point seed in glass recrystallizers of 1000 L in volume at growth rates of 10 to 25 mm/day in both the [001] and [100] directions. Measurements of the optical quality of 41 x 41 cm single crystal plates are presented.
Date: February 13, 1997
Creator: Zaitseva, N. P.; DeYoreo, J. J.; Dehaven, M. R.; Vital, R. L.; Carman, L. M. & Spears, H. R.
Partner: UNT Libraries Government Documents Department
open access

QCD: Challenges for the future

Description: Despite many experimental verifications of the correctness of our basic understanding of QCD, there remain numerous open questions in strong interaction physics and we focus on the role of future colliders in addressing these questions. We discuss possible advances in the measurement of {alpha}{sub s}, in the study of parton distribution functions, and in the understanding of low x physics at present colliders and potential new facilities. We also touch briefly on the role of spin physics in ad… more
Date: January 13, 1997
Creator: Burrows, P.; Dawson, S.; Orr, L. & Smith, W.H.
Partner: UNT Libraries Government Documents Department
open access

1-watt composite-slab Er:YAG laser. Revision 1

Description: A diode-side-pumped discrete-optic Er{sup 3+} :YAG laser employs pump-light coupling through a sapphire plate diffusion-bonded to the laser slab, removing heat directly at the pump face of the slab instead of requiring conduction through to its far side. This lowers the temperature in the gain region and gives reduced thermal lensing, which produces exceptional beam quality (M{sup 2} {approx} 1.3) at output powers {approx} 0.3 Watt. Powers above 1 Watt have been demonstrated with peak slope eff… more
Date: February 13, 1997
Creator: Page, R. H.; Bartels, R. A.; Beach, R. J.; Sutton, S. B.; Furu, L. H. & LaSala, J. E.
Partner: UNT Libraries Government Documents Department
open access

Laser peening of metals- enabling laser technology

Description: Laser peening, a surface treatment for metals, employs laser induced shocks to create deep and intense residual stresses in critical components. In many applications this technology is proving to be superior to conventional treatments such as shot peening. The laser peening process has generated sufficiently impressive results to move it from a laboratory demonstration phase into a significant industrial process. However until now this evolution has been slowed because a laser system meeting th… more
Date: November 13, 1997
Creator: Dane, C. B.; Hackel, L. A.; Daly, J. & Harrisson, J.
Partner: UNT Libraries Government Documents Department
open access

ABCC/RERF: Commemorating the First 50 Years and Looking to the Future [Symposium program]

Description: In 1946, President Harry Truman, in a document currently on display at the entrance to this auditorium, approved a directive to the National Academy of Sciences-National Research Council (NAS-NRC) to initiate a long-term investigation of the health effects associated with exposure to radiation from the atomic bombs. With funding provided by the Atomic Energy Commission, now the Department of Energy, NAS-NRC established the Atomic Bomb Casualty Commission (ABCC) in March 1947. The government of … more
Date: June 13, 1997
Partner: UNT Libraries Government Documents Department
open access

A local dynamic correlation function from inelastic neutron scattering

Description: Information about local and dynamic atomic correlations can be obtained from inelastic neutron scattering measurements by Fourier transform of the Q-dependent intensity oscillations at a particular frequency. A local dynamic structure function, S(r,{omega}), is defined from the dynamic scattering function, S(Q,{omega}), such that the elastic and frequency-integrated limits correspond to the average and instantaneous pair-distribution functions, respectively. As an example, S(r,{omega}) is calcu… more
Date: July 13, 1997
Creator: McQueeney, R.J.
Partner: UNT Libraries Government Documents Department
open access

APT target-blanket fabrication development

Description: Concepts for producing tritium in an accelerator were translated into hardware for engineering studies of tritium generation, heat transfer, and effects of proton-neutron flux on materials. Small-scale target- blanket assemblies were fabricated and material samples prepared for these performance tests. Blanket assemblies utilize composite aluminum-lead modules, the two primary materials of the blanket. Several approaches are being investigated to produce large-scale assemblies, developing fabri… more
Date: June 13, 1997
Creator: Fisher, D.L.
Partner: UNT Libraries Government Documents Department
open access

Study of laser plasma interactions in the relativistic regime

Description: We discuss the first experimental demonstration of electron acceleration by a laser wakefield over instances greater than a Rayleigh range (or the distance a laser normally propagates in vacuum). A self-modulated laser wakefield plasma wave is shown to have a field gradient that exceeds that of an RF linac by four orders of magnitude (E => 200 GV/m) and accelerates electrons with over 1-nC of charge per bunch in a beam with space-charge-limited emittance (1 mm-mrad). Above a laser power thre… more
Date: August 13, 1997
Creator: Umstadter, D.
Partner: UNT Libraries Government Documents Department
open access

A high energy physics perspective

Description: The status of the Standard model and role of symmetry in its development are reviewed. Some outstanding problems are surveyed and possible solutions in the form of additional {open_quotes}Hidden Symmetries {close_quotes} are discussed. Experimental approaches to uncover {open_quotes}New Physics{close_quotes} associated with those symmetries are described with emphasis on high energy colliders. An outlook for the future is given.
Date: January 13, 1997
Creator: Marciano, W. J.
Partner: UNT Libraries Government Documents Department
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