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Full-Text Articles in Physical Sciences and Mathematics
Measurement Of TC Suppression In Tungsten Using Magnetic Impurities, Betty A. Young, T. Saab, Blas Cabrera, J. J. Cross, R. M. Clarke, R. A. Abusaidi
Measurement Of TC Suppression In Tungsten Using Magnetic Impurities, Betty A. Young, T. Saab, Blas Cabrera, J. J. Cross, R. M. Clarke, R. A. Abusaidi
Physics
We have measured the effects of dilute magnetic-atom doping on the superconducting transition temperature of tungsten thin films. Our “Tc tuning” technique is accurate, precise, and simple. Experiments were performed using dc-magnetron-sputtered tungsten films with undoped values of Tc in the range of 70–150 mK. The magnetic-atom doping was achieved using ion implantation. Specific Tc suppressions of between 5% and 65% were targeted and observed in this study. The transition width of each undoped sample was ≈1 mK and the transition widths remained sharp after implantation with 56Fe+ ions. Our data are in good agreement …
Differential Photometry Of Suspected Cataclysmic Variables, N. Bennert, I. König, E. Manthey, H. Bleul, K. Fieger, M. Hess, A. Hovest, W. Hovest, T. Jürges, J. Kleimann, C. Kriegeskorte, E. Krusch, D. Münstermann, D. Reymann, K. Rösler, M. Nielbock, M. Pohlen, L. Schmidtobreick, C. Tappert, R. Vanscheidt
Differential Photometry Of Suspected Cataclysmic Variables, N. Bennert, I. König, E. Manthey, H. Bleul, K. Fieger, M. Hess, A. Hovest, W. Hovest, T. Jürges, J. Kleimann, C. Kriegeskorte, E. Krusch, D. Münstermann, D. Reymann, K. Rösler, M. Nielbock, M. Pohlen, L. Schmidtobreick, C. Tappert, R. Vanscheidt
Physics
No abstract provided.
Bacterial Magnetosomes: Microbiology, Biomineralization And Biotechnological Applications, Dirk Schlϋer, Richard B. Frankel
Bacterial Magnetosomes: Microbiology, Biomineralization And Biotechnological Applications, Dirk Schlϋer, Richard B. Frankel
Physics
Magnetotactic bacteria orient and migrate along geomagnetic field lines. This ability is based on intracellular magnetic structures, the magnetosomes, which comprise nanometer-sized, membrane-bound crystals of the magnetic iron minerals magnetite (Fe3O4) or greigite (Fe3O4). Magnetosome formation is achieved by a mineralization process with biological control over the accumulation of iron and the deposition of the mineral particle with specific size and orientation within a membrane vesicle at specific locations in the cell. This review focuses on the current knowledge about magnetotactic bacteria and will outline aspects of the physiology and molecular biology …
Two New Topologically Ordered Glass Phases Of Smectics Confined In Anisotropic Random Media, Brad Jacobsen, Karl Saunders, Leo Radzihovsky, John Toner
Two New Topologically Ordered Glass Phases Of Smectics Confined In Anisotropic Random Media, Brad Jacobsen, Karl Saunders, Leo Radzihovsky, John Toner
Physics
Smectics in strained aerogel exhibit two new glassy phases. The strain both ensures the stability of these phases and determines their nature. One type of strain induces an “ XY Bragg glass,” while the other creates a novel, triaxially anisotropic “ m = 1 Bragg glass.” The latter exhibits anomalous elasticity, characterized by exponents that we calculate to high precision. We predict the phase diagram, and numerous other experimentally observable scaling laws, for the system.
Charge Dynamics In The Half-Metallic Ferromagnet Cro2, E. J. Singley, Christopher P. Weber, D. N. Basov, A. Barry, J. M. D. Coey
Charge Dynamics In The Half-Metallic Ferromagnet Cro2, E. J. Singley, Christopher P. Weber, D. N. Basov, A. Barry, J. M. D. Coey
Physics
Infrared spectroscopy is used to investigate the electronic structure and charge carrier relaxation in crystalline films of CrO2 which is the simplest of all half-metallic ferromagnets. Chromium dioxide is a bad metal at room temperature but it has a remarkably low residual resistivity (<5 >μΩ cm) despite the small spectral weight associated with free carrier absorption. The infrared measurements show that low residual resistivity is due to the collapse of the scattering rate at ω<2000 >cm-1. The blocking of the relaxation channels at low v and T can be attributed to the unique electronic structure of a …
Complete View Of Stark Wave-Packet Evolution, M. B. Campbell, Thomas J. Bensky, Robert R. Jones
Complete View Of Stark Wave-Packet Evolution, M. B. Campbell, Thomas J. Bensky, Robert R. Jones
Physics
Picosecond laser pulses have been used to produce Rydberg wave packets in calcium atoms in the presence of a strong static electric field. The dynamics of the Stark wave packets have been observed by measuring the momentum-space probability distribution as a function of time. The full precession of the electronic orbital angular momentum, the appearance of a large-amplitude, linear oscillation of the electronic dipole moment, and a pronounced, periodic up-down asymmetry in the momentum distribution are all observed directly.
Spume Drops Produced By The Wind Tearing Of Wave Crests, Richard P. Barber Jr., Magdalena Anguelova, Jin Wu
Spume Drops Produced By The Wind Tearing Of Wave Crests, Richard P. Barber Jr., Magdalena Anguelova, Jin Wu
Physics
The wind tearing of breaking wave crests produces spume drops. The authors report preliminary laboratory data from direct and unambiguous observation of this process under various wind conditions using a video imaging technique. Results include the size distribution and production rates of these drops. The curves for production rates at different wind speeds merge effectively when normalized by the number of breaking events. This confirms that wave breaking occurrence, not the wind speed, is a dominant factor in spume production.
Reviews Of Atomic Audit: The Costs And Consequences Of Us Nuclear Weapons Since 1940 By Stephen Schwartz; And Killing Detente: The Right Attacks The Cia By Anne Cahn, David W. Hafemeister
Reviews Of Atomic Audit: The Costs And Consequences Of Us Nuclear Weapons Since 1940 By Stephen Schwartz; And Killing Detente: The Right Attacks The Cia By Anne Cahn, David W. Hafemeister
Physics
Science aims to link cause and effect for natural phenomena. Linking cause and effect for historical events is often more difficult since historical events cannot be tested by rerunning history with varied parameters. Despite the difficulty, it is worthwhile to review the causes behind the magnitude of the U.S. nuclear buildup. Two critical questions should guide this analysis: How much of the $5.8 trillion (1996 dollars) that the U.S spent to build 70,000 nuclear warheads, deployed on 75,000 missiles and 8600 bombers, was too much? And, was the effectiveness of the Soviet military exaggerated with false predictions? These two books …
Leading Charm In Hadron-Nucleus Interactions In The Intrinsic Charm Model, Thomas D. Gutierrez, R. Vogt
Leading Charm In Hadron-Nucleus Interactions In The Intrinsic Charm Model, Thomas D. Gutierrez, R. Vogt
Physics
Leading charm hadrons produced in hadron-nucleus interactions cannot be adequately described within the parton fusion model. Recent results on charm baryon production in ∑-A interactions at 330 GeV with the WA89 detector disagree with fusion predictions. Intrinsic heavy quark pairs in the ∑- (dds) wavefunction provide a simple mechanism for producing fast charm hadrons. We calculate leading charm baryon production from ∑-, ∏- and p projectiles in a two component model combining parton fusion with intrinsic charm. Final state D-, ∑ncn0, ≡ncn+, and ∧ncn+ dσ/dxnF …
History Of The Forum On Physics And Society, David W. Hafemeister
History Of The Forum On Physics And Society, David W. Hafemeister
Physics
Physics is a major component of many of society's difficult issues: nuclear arms and their proliferation, energy shortages and energy impacts, climate change and technical innovation. Because physics principles underlie so many of these societal issues and because physics offers a way to quantify some aspects of them, members of the American Physical Society (APS) should be encouraged to understand, analyze and debate them. That's precisely why APS members formed the Forum on Physics and Society (FPS). To those of us who have been long involved in FPS affairs, it seems but yesterday that we attended the organizing meeting at …