Search Results - "Howell, R. H."

Characterization of Free Volume in a Bulk Metallic Glass Using Positron Annihilation Spectroscopy by Flores, K. M., Suh, D., Dauskardt, R. H., Asoka-Kumar, P., Sterne, P. A., Howell, R. H.

“…The free volume of metallic glasses has a significant effect on atomic relaxation processes, although a detailed understanding of the nature and distribution…”
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Positron annihilation spectroscopy and small-angle neutron scattering characterization of the effect of Mn on the nanostructural features formed in irradiated Fe-Cu-Mn alloys by Glade, S. C., Wirth, B. D., Odette, G. R., Asoka-Kumar, P., Sterne, P. A., Howell, R. H.

“…The size, number density, and composition of the nanometre-sized defects responsible for the hardening and embrittlement in irradiated Fe-0.9 wt% Cu and Fe-0.9…”
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Composition and magnetic character of nanometre-size Cu precipitates in reactor pressure vessel steels: Implications for nuclear power plant lifetime extension by Asoka-Kumar, P., Wirth, B.D., Sterne, P.A., Howell, R.H., Odette, G.R.

“…The sensitivity of positrons to nanometre-size Cu precipitates in Fe alloys has enabled us to apply a novel spin-polarized element-specific method to probe the…”
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Direct observation of carbon-decorated defects in fatigued type 304 stainless steel using positron annihilation spectroscopy by Asoka-Kumar, P, Hartley, J.H, Howell, R.H, Sterne, P.A, Akers, D, Shah, V, Denison, A

“…We have directly observed carbon decoration of defects in fatigued 304 stainless steel using positron annihilation spectroscopy. The formation and evolution of…”
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Induction of silent myocardial ischemia with mental stress testing: Relation to the triggers of ischemia during daily life activities to ischemic functional severity by Gottdiener, John S., Krantz, David S., Howell, Robert H., Hecht, Gabriela M., Klein, Jacob, Falconer, Jennifer J., Rozanski, Alan

“…Objectives. This study examined the relations among the triggers of ischemia during the activities of daily life, mental stress-induced ischemia in the…”
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Spatial sampling of crystal electrons by in-flight annihilation of fast positrons by Hunt, A. W, Cassidy, D. B, Selim, F. A, Haakenaasen, R, Cowan, T. E, Howell, R. H, Lynn, K. G, Golovchenko, J. A

“…Energetic, positively charged particles travelling along a low-index crystal direction undergo many highly correlated, small-angle scattering events; the…”
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Atomic-based calculations of two-detector Doppler-broadening spectra by Sterne, P.A, Asoka-Kumar, P, Howell, R.H

“…We present a simplified approach for calculating Doppler-broadening spectra based purely on atomic calculations. This approach avoids the need for detailed…”
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Hostility and myocardial ischemia in coronary artery disease patients: evaluation by gender and ischemic index by Helmers, K F, Krantz, D S, Howell, R H, Klein, J, Bairey, C N, Rozanski, A

“…Two studies assess relationships of hostility to extent and severity of exercise-induced cardiac ischemia and daily life ischemia in patients with coronary…”
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Doppler broadening of in-flight positron annihilation radiation due to electron momentum by Hunt, A W, Cassidy, D B, Sterne, P A, Cowan, T E, Howell, R H, Lynn, K G, Golevchenko, J A

“…We report the first observation of electron momentum contributions to the Doppler broadening of radiation produced by in-flight two-photon annihilation in…”
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High energy beam lifetime analysis by Howell, R.H, Sterne, P.A, Hartley, J, Cowan, T.E

“…We have developed a positron lifetime defect analysis capability based on a 3 MeV electrostatic accelerator. The high energy beam lifetime spectrometer is…”
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The circadian variation of cardiovascular stress levels and reactivity: relationship to individual differences in morningness/eveningness by Nebel, L E, Howell, R H, Krantz, D S, Falconer, J J, Gottdiener, J S, Gabbay, F H

“…Two studies assessed the circadian variation of cardiovascular responses to stress in healthy and coronary artery disease (CAD) populations. In within-subjects…”
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Positron annihilation studies of fatigue in 304 stainless steel by Hartley, J.H, Howell, R.H, Asoka-Kumar, P, Sterne, P.A, Akers, D, Denison, A

“…Positron annihilation lifetime measurements were made on well calibrated fatigue samples of SS-304. Measurements were made on a high and low carbon alloy. Two…”
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Transient coronary occlusion with mental stress by Papademetriou, Vasilios, Gottdiener, John S., Kop, Willem J., Howell, Robert H., Krantz, David S.

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Electronic structure calculations of vacancies and their influence on materials properties by Sterne, P.A., van Ek, J., Howell, R.H.

“…We provide two examples to illustrate how electronic structure calculations contribute to our understanding of vacancies and their role in determining…”
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Local charge-density change and superconductivity: a positron study by JEAN, Y. C, SUNDAR, C. S, WANG, Z. Z, TURCHI, P. E. A, HOWELL, R. H, WACHS, A. L, FLUSS, M. J, BHARATHI, A, KYLE, J, NAKANISHI, H, TSENG, P. K, HOR, P. H, MENG, R. L, HUANG, Z. J, CHU, C. W

“…The temp. dependence at 10- 300 K of the positron lifetime is measured in YBa sub 2 (Cu sub 1 sub - sub x M sub x )O sub 6 sub + sub / delta / (M=Zn, Ga) with…”
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First observation of resonant excitation of high-n states in positronium by ZIOCK, K. P, HOWELL, R. H, MAGNOTTA, F, FAILOR, R. A

“…We have performed the first excitation of high-{ital n} states of positronium using resonant, two-photon excitation applied to the {ital n}=1 to 2 and 2 to…”
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Effects of Mental stress on Coronary epicardial vasomotion and flow velocity in Coronary artery disease : Relationship with hemodynamic stress responses by KOP, Willem J, KRANTZ, David S, HOWELL, Robert H, FERGUSON, Michael A, PAPADEMETRIOU, Vasilios, LU, David, POPMA, Jeffrey J, QUIGLEY, John F, VERNALIS, Marina, GOTTDIENER, John S

“…This study examines the prevalence and hemodynamic determinants of mental stress-induced coronary vasoconstriction in patients undergoing diagnostic coronary…”
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Transmission electron study of heteroepitaxial growth in the BiSrCaCuO system by Chaiken, A., Wall, M. A., Howell, R. H., Bozovic, I., Eckstein, J. N., Virshup, G. F.

“…Films of Bi2Sr2CaCu2O8 and Bi2Sr2CuO6 have been grown using Atomic-Layer-by-Layer Molecular Beam Epitaxy (ALL-MBE) on lattice-matched substrates. These…”
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Evidence for a common high-temperature superconducting effect in La1.85Sr0.15CuO4 and YBa2Cu3O7 by JEAN, Y. C, KYLE, J, CHU, C. W, NAKANISHI, H, TURCHI, P. E. A, HOWELL, R. H, WACHS, A. L, FLUSS, M. J, MENG, R. L, HOR, H. P, HUANG, J. Z

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Two-dimensional electron-positron momentum measurement at a copper single-crystal surface by HOWELL, R. H, MEYER, P, ROSENBERG, I. J, FLUSS, M. J

“…The first two-dimensional momentum measurements of annihilating positron--electron pairs at a solid surface are reported. Positrons of 18 keV or 740 eV…”
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