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Theoretical modeling and experimental characterization of planar defects in Y sub 2 Ba sub 4 Cu sub 6+x O sub 14+x

Description: Crystallographic defects and phase transformations in the system Y{sub 2}Ba{sub 4}Cu{sub 6 + x}O{sub 14 + x}(0{le}{times}{le}4) are investigated by high resolution transmission electron microscopy (TEM) and static lattice, three dimensional Monte Carlo computer simulations. High resolution images of partially transformed (x = 2 to x = 1) material reveal a prevalence of CuO planar defects (stacking faults) associated with the transformation and an absence of disturbance to the perovskite Ba-Y-Ba… more
Date: November 1, 1990
Creator: Burmester, C. P.; Fendorf, M.; Gronsky, R. & Wille, L. T.
Partner: UNT Libraries Government Documents Department
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Framework for control system development

Description: Control systems being developed for the present generation of accelerators will need to adapt to changing machine and operating state conditions. Such systems must also be capable of evolving over the life of the accelerator operation. In this paper we present a framework for the development of adaptive control systems.
Date: November 1, 1991
Creator: Cork, C. & Nishimura, Hiroshi.
Partner: UNT Libraries Government Documents Department
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Tempered glass

Description: This document describes a demonstration for making tempered glass using minimal equipment. The demonstration is intended for a typical student of materials science, at the high school level or above. (JL)
Date: November 1, 1991
Creator: Bunnell, L.R.
Partner: UNT Libraries Government Documents Department
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Monte Carlo optimization of depth-of-interaction resolution in PET crystals

Description: The light distribution along one edge of a PET scintillation crystal was investigated with a Monte Carlo simulation. This position-dependent light can be used to measure the 511 keV photon interaction position in the crystal on an event by event basis, thus reducing radial elongation. The expected full width at half maximum (FWHM) of the light distribution on the 3 {times} 30 mm{sup 2} surface of a 3 {times} 10 {times} 30 mm{sup 3} bismuth germanate (BGO) crystal surrounded by a diffuse reflect… more
Date: November 1, 1991
Creator: DeVol, T. A. (Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering); Moses, W. W. & Derenzo, S. E. (Lawrence Berkeley Lab., CA (United States))
Partner: UNT Libraries Government Documents Department
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Numerical simulations of heterogeneous chemical reactions coupled to fluid flow in varying thermal fields

Description: A numerical simulator of reactive chemical transport with coupling from precipitation-dissolution reactions to fluid flow, via changes of porosity and permeability, is applied to precipitation-dissolution of quartz and calcite in spatially and temporally variable fields of temperature. Significant effects on fluid flow are found in the quartz-silicic acid system in the presence of persistent, strong gradient of temperature. Transient heat flow in the quartz-silicic acid system and in a calcite-… more
Date: November 1, 1991
Creator: Carnahan, C.L.
Partner: UNT Libraries Government Documents Department
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Review of CERN heavy-ion physics

Description: Results from the heavy-ion experiments at the CERN SPS are reviewed in the context of possible formation and identification of a quark-gluon plasma (QGP).
Date: November 1, 1991
Creator: Odyniec, G.
Partner: UNT Libraries Government Documents Department
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D0 papers on B-physics submitted to DPF '96: b-quark inclusive cross sections and b anti-b correlations using dimuons from the D0 experiment; Single muon production in the forward region at [radical]s=1. 8 TEV; Rapidity dependence of the inclusive J[psi] production in the forward region [radical]s=1. 8 TEV; A search for b [r arrow] X[mu][sup +][mu][sup [minus]] and B[sup 0] [r arrow] [mu][sup +][mu][sup [minus]] decays in p anti-p collisions at [radical]s=1. 8 TEV

Description: Paper 1: Using dimuons collected with the D0 detector during the 1993--1995 Tevatron collider run, the authors have measured the b-quark cross section and b[anti b] correlations as given by the difference in azimuthal angle between the two muons. Both measurements agree with the NLO QCD predictions within experimental and theoretical errors. (Three other papers are included in this report.)
Date: November 1, 1996
Creator: Vititoe, D.L. (Arizona Univ., Tucson, AZ (United States). Dept. of Physics); Kozelov, Alexander; Jesik, Richard & Collaboration., D0
Partner: UNT Libraries Government Documents Department
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Basic features of coherent radiation generated by relativistic charge bunches

Description: Radiation generated by relativistic charges can be analyzed and described in exquisite detail. One reason that such detailed analysis is possible is because the phases of radiated photons often are determined completely by the initial conditions of the relativistic charges and the radiating system. The phase relationships between the initial charges and the radiated photons represent coherence in the emitted radiation. A previous paper described how this coherence could affect the spatial and s… more
Date: November 1, 1990
Creator: Moran, M. J. & Chang, B.
Partner: UNT Libraries Government Documents Department
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Brittle and Ductile Behavior in Carbon Nanotubes

Description: Article discussing research on the response of carbon nanotubes to a tensile load.
Date: November 23, 1998
Creator: Buongiorno Nardelli, Marco; Yakobson, Boris I. & Bernholc, Jerry
Partner: UNT College of Arts and Sciences
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Properties of CMOS devices and circuits fabricated on high-resistivity, detector-grade silicon

Description: A CMOS process that is compatible with silicon p-i-n radiation detectors has been developed and characterized. A total of twelve mask layers are used in the process. The NMOS device is formed in a retrograde well while the PMOS device is fabricated directly in the high-resistivity silicon. Isolation characteristics are similar to a standard foundary CMOS process. Circuit performance using 3 {mu}m design rules has been evaluated. The measured propagation delay and power-delay product for a 51-st… more
Date: November 1, 1991
Creator: Holland, S.
Partner: UNT Libraries Government Documents Department
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Genetic changes in Mammalian cells transformed by helium cells

Description: Midterm Syrian Hamster embryo (SHE) cells were employed to study high LET-radiation induced tumorigenesis. Normal SHE cells (secondary passage) were irradiated with accelerated helium ions at an incident energy of 22 MeV/u (9--10 keV/{mu}m). Transformed clones were isolated after growth in soft agar of cells obtained from the foci of the initial monolayer plated postirradiation. To study the progression process of malignant transformation, the transformed clones were followed by monolayer subcu… more
Date: November 1, 1990
Creator: Durante, M.; Grossi, G. (Naples Univ. (Italy). Dipt. di Scienze Fisiche); Yang, T.C. & Roots, R. (Lawrence Berkeley Lab., CA (USA))
Partner: UNT Libraries Government Documents Department
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Theoretical overview: Hot and dense QCD in equilibrium

Description: Static and dynamical properties of QCD at finite temperature and density are reviewed. Non-perturbative aspects of the QCD plasma and modification of the hadron properties associated with the chiral transition are discussed on the basis of lattice data, effective theories and QCD sum rules. Special emphasis is laid on the importance of the finite baryon density to see the effects of the restoration of chiral symmetry in experiment.
Date: November 1, 1991
Creator: Hatsuda, Tetsuo.
Partner: UNT Libraries Government Documents Department
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Constraints on fermion mixing with exotics

Description: We analyze the constraints on the mixing angles of the standard fermions with new heavy particles with exotic SU(2) {times} U(1) quantum number assignments (left-handed singlets or right-handed doublets), that appear in many extensions of the electroweak theory. The updated Charged Current and Neutral Current experimental data, including also the recent Z-peak measurements, are considered. The results of the global analysis of all these data are then presented.
Date: November 1, 1991
Creator: Nardi, E. (Michigan Univ., Ann Arbor, MI (United States). Randall Lab. of Physics); Roulet, E. (Fermi National Accelerator Lab., Batavia, IL (United States)) & Tommasini, D. (Valencia Univ. (Spain). Dept. de Fisica Teorica)
Partner: UNT Libraries Government Documents Department
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Example of a quantum field theory based on a nonlinear Lie algebra

Description: In this contribution to Tini Veltman's Festschrift we shall give a paedagogical account of our work on a new class of gauge theories called W gravities. They contain higher spin gauge fields, but the usual no-go theorems for interacting field theories with spins exceeding two do not apply since these theories are in two dimensions. It is, of course, well known that ghost-free interacting massless spin 2 fields ( the metric') are gauge fields, and correspond to the geometrical notion of general … more
Date: November 1, 1991
Creator: Schoutens, K. (State Univ. of New York, Stony Brook, NY (United States). Inst. for Theoretical Physics); Sevrin, A. (Lawrence Berkeley Lab., CA (United States)) & van Nieuwenhuizen, P. (European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.)
Partner: UNT Libraries Government Documents Department
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Generation of nonequilibrium optical phonons in GaAs/AlAs quantum wells by intrasubband and intersubband scatterings

Description: The generation of a nonequilibrium population of optical phonons by photoexcited hot electrons in semiconductor quantum wells is investigated theoretically. The microscopic model of electron-phonon interaction proposed by Huang and Zhu has been used to compute the distributions of confined longitudinal optical phonons and interface modes in GaAs/AlAs quantum wells as a function of well width. Experimental tests of the calculated distributions by Raman scattering are discussed.
Date: November 1, 1991
Creator: Wald, K.R.; Kim, Dai-sik & Yu, P.Y.
Partner: UNT Libraries Government Documents Department
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Quantum W sub 3 gravity

Description: We briefly review some results in the theory of quantum W{sub 3} gravity in the chiral gauge. We compare them with similar results in the analogous but simpler cases of d = 2 induced gauge theories and d = 2 induced gravity.
Date: November 1, 1991
Creator: Schoutens, K. (State Univ. of New York, Stony Brook, NY (United States). Inst. for Theoretical Physics); Sevrin, A. (Lawrence Berkeley Lab., CA (United States)) & van Nieuwenhuizen, P. (European Organization for Nuclear Research, Geneva (Switzerland). Theory Div. State Univ. of New York, Stony Brook, NY (United States). Inst. for Theoretical Physics)
Partner: UNT Libraries Government Documents Department
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The structure and faceting behavior of tilt grain boundaries in aluminum

Description: This work describes a number of experimental observations on the structure and behavior of {Sigma}99 and other near-90{degree} <110> tilt boundaries in bicrystals of aluminum. The continuous bicrystal structure employed in these studies is based on the symmetry properties inherent in heteroepitaxial growth. A thin film grown in this geometry consists of intertwined grains surrounding each other but with only two grain orientations.
Date: November 1, 1990
Creator: Dahmen, U.
Partner: UNT Libraries Government Documents Department
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Stability of Resonator Configurations in the Presence of Free-Electron Laser Interactions

Description: The stability of empty resonators (or cold cavities) has been widely studied, and is well understood. Here we consider the stability of symmetric resonator systems when there is a free-electron laser (FEL) interaction present within the cavity. We first construct a linear thick-lens model of the FEL and analytically study the dependence of resonator stability on its geometry. Next, we employ a nonlinear, three-dimensional FEL oscillator code to study the dependence of FEL performance on the cav… more
Date: November 1, 1992
Creator: Krishnagopal, S. & Sessler, Andrew M.
Partner: UNT Libraries Government Documents Department
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Beam Comissioning of the PEP-II High Energy Ring

Description: The PEP-II High Energy Ring (HER), a 9 GeV electron storage ring, has been in commissioning since spring 1997. Initial beam commissioning activities focused on systems checkout and commissioning and on determining the behavior of the machine systems at high beam currents. This phase culminated with the accumulation of 0.75 A of stored beam-sufficient to achieve design luminosity--in January 1998 after 3.5 months of beam time. Collisions with the 3 GeV positron beam of the Low Energy Ring (LER) … more
Date: November 12, 1998
Creator: Wienands, U.; Anderson, S.; Assmann, R.; Bharadwaj, V.; Cai, Y.; Clendenin, J. et al.
Partner: UNT Libraries Government Documents Department
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Economic Analysis of Ilumex, A Project to Promote Energy-Efficient Residential Lighting in Mexico

Description: A higher penetration of compact fluorescent lamps (CFLs) for household lighting can reduce growth in peak electricity demand, reduce sales of subsidized electricity, and lessen environmental impacts. This paper describes an economic analysis of a project designed to promote high penetration rates of CFLs in two cities in Mexico. Our analysis indicates that the project will bring substantial net economic benefits to Mexico, the utility, and the average customer. In the absence of any subsidy to … more
Date: November 1, 1993
Creator: Sathaye, Jayant A.; Friedmann, R.; Meyers, S.; de Buen, O.; Gadgil, A. J.; Vargas, E. et al.
Partner: UNT Libraries Government Documents Department
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A Generalized {ital K} Correction for Type Ia Supernovae: Comparing {ital R}-band Photometry Beyond {ital z=9.2} with B,V, and {ital R}-band Nearby Photometry

Description: Photometric measurements show that, as a group, nearby Type Ia supernovae follow similar light curves and reach similar peak magnitudes (Branch & Tammann 1992). Thus, these supernovae may serve as standard candles or calibrated candles at cosmological distances. Magnitudes of local and distant supernovae, both in the same filter band, are compared using a K correction to account for the different spectral regions incident on that filter. A generalized approach compares magnitudes in different b… more
Date: November 1, 1995
Creator: Kim, Alex; Goodbar, Ariel & Perlmutter, Saul
Partner: UNT Libraries Government Documents Department
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