693,563 research outputs found

    Adatom diffusion in high electric fields

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    Strong electric fields are known to create biased adatom migration on metallic surfaces. We present a Kinetic Monte Carlo model that can simulate adatom migration on a tungsten (W) surface in electric fields. We validate our model by using it to calculate the drift velocity of the adatom at different fields and temperature and comparing the results with experimental data from the literature. We obtain excellent agreement

    Concerning Spin as Mind-pixel: How Mind Interacts with the Brain through Electric Spin Effects

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    Electric spin effects are effects of electric fields on the dynamics/motions of nuclear/electron spins and related phenomena. Since classical brain activities are largely electric, we explore here a model of mind-brain interaction within the framework of spin-mediated consciousness theory in which these effects in the varying high-voltage electric fields inside neural membranes and proteins mediate mind-brain input and output processes. In particulars, we suggest that the input processes in said electric fields are possibly mediated by spin transverse forces and/or Dirac-Hestenes electric dipoles both of which are associated with the nuclear/electronic spin processes. We then suggest that the output processes (proactive spin processes) in said electric fields possibly involve Dirac negative energy extraction processes, shown by Solomon, and also Dirac-Hestenes electric dipole interactions of nuclei/electrons besides non-local processes driven by quantum information. We propose that these output processes modulate the action potentials, thus influencing the brain, by affecting the cross-membrane electric voltages and currents directly and/or indirectly through changing the capacitance, conductance and/or battery in the Hudgkin-Huxley model. These propositions are based on our own experimental findings, further theoretical considerations, and studies reported by others in the fields of spintronics, high-energy physics and alternative energy research

    Gel Electrophoresis of DNA Knots in Weak and Strong Electric Fields

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    Gel electrophoresis allows to separate knotted DNA (nicked circular) of equal length according to the knot type. At low electric fields, complex knots being more compact, drift faster than simpler knots. Recent experiments have shown that the drift velocity dependence on the knot type is inverted when changing from low to high electric fields. We present a computer simulation on a lattice of a closed, knotted, charged DNA chain drifting in an external electric field in a topologically restricted medium. Using a simple Monte Carlo algorithm, the dependence of the electrophoretic migration of the DNA molecules on the type of knot and on the electric field intensity was investigated. The results are in qualitative agreement with electrophoretic experiments done under conditions of low and high electric fields: especially the inversion of the behavior from low to high electric field could be reproduced. The knot topology imposes on the problem the constrain of self-avoidance, which is the final cause of the observed behavior in strong electric field.Comment: 17 pages, 5 figure

    The electric field-induced antiferroelectric to ferroelectric phase transition in some (Pb,La)Zr0.55Ti0.45O3 ceramics

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    Lanthanum substituted lead zirconate-titanate (PLZT) ceramics of composition 11.1/55/45 have been studied by measuring high electric field properties. Dc bias, dielectric and P-E hysteresis loop measurements have been employed to construct an E (electric field) versus T (temperature) phase diagram. At lower temperatures and small electric fields an antiferroelectric phase with tetragonal symmetry has been found. Applying high electric fields gives rise to a field-induced phase transition from the antiferroelectric to the ferroelectric state, however, without X-ray detectable change in crystal symmetry

    Response of convection electric fields in the magnetosphere to IMF orientation change

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    [1] The transient response of convection electric fields in the inner magnetosphere to southward turning of the interplanetary magnetic field (IMF) is investigated using in‐situ electric field observations by the CRRES and Akebono spacecraft. Electric fields earthward of the inner edge of the electron plasma sheet show quick responses simultaneously with change in ionospheric electric fields, which indicates the arrival of the first signal related to southward turning. A coordinated observation of the electric field by the CRRES and Akebono spacecraft separated by 5 RE reveals a simultaneous increase in the dawn‐dusk electric field in a wide region of the inner magnetosphere. A quick response associated with the southward turning of the IMF is also identified in in‐situ magnetic fields. It indicates that the southward turning of the IMF initiates simultaneous (less than 1 min) enhancements of ionospheric electric fields, convection electric fields in the inner magnetosphere, and the ring or tail current and region 2 FACs. In contrast, a quick response of convection electric fields is not identified in the electron plasma sheet. A statistical study using 161 events of IMF orientation change in 1991 confirms a prompt response within 5 min for 80% of events earthward of the electron plasma sheet, while a large time lag of more than 30 min is identified in electric fields in the electron plasma sheet. The remarkable difference in the response of electric fields indicates that electric fields in the electron plasma sheet are weakened by high conductance in the magnetically conjugated auroral ionosphere.https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2009JA014277https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2009JA014277Published versio

    Anomalous Electric Fields in n-InSb under High Magnetic Fields. I-Experiment

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    An investigation was made of the anomalous electric field in its various aspects in n-type InSb subjected to strong magnetic field at 77K and 273K, which lead to the conclusion that no open contradiction arose between a part of the present observations and the predictions attainable from Yoshida's model of semimetals. There remained, however, the other part of the experimental results unexplained, being rather natural since an inner property of indium antimonide does not seem so simple comparing with the compensated metals, bismuth and antimony. Especially as for the mechanism of an inversion phenomenon of the polarity of a negative anomalous field at a critical pulse current, we have no available theory to explain at present stage

    Low magnetic field reversal of electric polarization in a Y-type hexaferrite

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    Magnetoelectric multiferroics in which ferroelectricity and magnetism coexist have attracted extensive attention because they provide great opportunities for the mutual control of electric polarization by magnetic fields and magnetization by electric fields. From a practical point view, the main challenge in this field is to find proper multiferroic materials with a high operating temperature and great magnetoelectric sensitivity. Here we report on the magnetically tunable ferroelectricity and the giant magnetoelectric sensitivity up to 250 K in a Y-type hexaferrite, BaSrCoZnFe11AlO22. Not only the magnitude but also the sign of electric polarization can be effectively controlled by applying low magnetic fields (a few hundreds of Oe) that modifies the spiral magnetic structures. The magnetically induced ferroelectricity is stabilized even in zero magnetic field. Decayless reproducible flipping of electric polarization by oscillating low magnetic fields is shown. The maximum linear magnetoelectric coefficient reaches a high value of ~ 3.0\times10^3 ps/m at 200 K.Comment: 9 pages, 5 figures, a couple of errors are correcte
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