1,648 research outputs found

    Current induced domain wall dynamics in the presence of spin orbit torques

    Full text link
    Current induced domain wall (DW) motion in perpendicularly magnetized nanostripes in the presence of spin orbit torques is studied. We show using micromagnetic simulations that the direction of the current induced DW motion and the associated DW velocity depend on the relative values of the field like torque (FLT) and the Slonczewski like torques (SLT). The results are well explained by a collective coordinate model which is used to draw a phase diagram of the DW dynamics as a function of the FLT and the SLT. We show that a large increase in the DW velocity can be reached by a proper tuning of both torques.Comment: 9 pages, 3 figure

    ACL ARTHROSCOPIC RECONSTRUCTION WITH DOUBLE-STRANDED HAMSTRING TENDONS

    Get PDF
    INTRODUCTION: In the past the ACL reconstruction was performed using patellar tendon. This technique involved several advantages like post operative good stability and easy tendon gathering. Nevertheless it causes some disadvantages like pain during the act of kneeling, longer period of rehabilitation because of the tendon stiffness and dysfunction of the patella movement that can provoke patellar-femoral osteoarthritis. This is the reason why a lot of authors tried to find out other techniques that could avoid these complications. We practised the ACL reconstruction using doubled semitendinosus and gracilis tendons because it is demonstrated that they have a biological structure and biomechanical behaviour more similar to normal ACL. In this sense the use of these tendons must include tensibility closer to normal ACL, larger surface of revascularization and low risk of joint stiffness after surgery. The purpose of the present study is to evaluate clinical results using this technique in patients involved both in not professional and professional sports

    Calculating energy derivatives for quantum chemistry on a quantum computer

    Get PDF
    Modeling chemical reactions and complicated molecular systems has been proposed as the `killer application' of a future quantum computer. Accurate calculations of derivatives of molecular eigenenergies are essential towards this end, allowing for geometry optimization, transition state searches, predictions of the response to an applied electric or magnetic field, and molecular dynamics simulations. In this work, we survey methods to calculate energy derivatives, and present two new methods: one based on quantum phase estimation, the other on a low-order response approximation. We calculate asymptotic error bounds and approximate computational scalings for the methods presented. Implementing these methods, we perform the world's first geometry optimization on an experimental quantum processor, estimating the equilibrium bond length of the dihydrogen molecule to within 0.014 Angstrom of the full configuration interaction value. Within the same experiment, we estimate the polarizability of the H2 molecule, finding agreement at the equilibrium bond length to within 0.06 a.u. (2% relative error).Comment: 19 pages, 1 page supplemental, 7 figures. v2 - tidied up and added example to appendice

    Statistical analysis of industrial indicators of enterprises of various property forms

    Get PDF
    In this paper we study the impact of the economic crisis on the enterprises of subsection DM "Manufacture of transport means and equipment" manufacturing industries of Russia in the context of ownership. The study is based on comparative statistical analysis of available indicators of enterprises producing vehicles in 2013, 2014 and 2015 located in Russian, foreign and co-property

    Domain wall tilting in the presence of the Dzyaloshinskii-Moriya interaction in out-of-plane magnetized magnetic nanotracks

    Full text link
    We show that the Dzyaloshinskii-Moriya interaction (DMI) can lead to a tilting of the domain wall (DW) surface in perpendicularly magnetized magnetic nanotracks when DW dynamics is driven by an easy axis magnetic field or a spin polarized current. The DW tilting affects the DW dynamics for large DMI and the tilting relaxation time can be very large as it scales with the square of the track width. The results are well explained by an analytical model based on a Lagrangian approach where the DMI and the DW tilting are included. We propose a simple way to estimate the DMI in a magnetic multilayers by measuring the dependence of the DW tilt angle on a transverse static magnetic field. Our results shed light on the current induced DW tilting observed recently in Co/Ni multilayers with inversion asymmetry, and further support the presence of DMI in these systems.Comment: 12 pages, 3 figures, 1 Supplementary Material

    A Homogenization Approach for Turbulent Channel Flows over Porous Substrates: Formulation and Implementation of Effective Boundary Conditions

    Get PDF
    The turbulent flow through a plane channel bounded by a single permeable wall is considered; this is a problem of interest since a carefully chosen distribution of grains and voids in the porous medium can result in skin friction reduction for the flow in the channel. In the homogenization approach followed here, the flow is not resolved in the porous layer, but an effective velocity boundary condition is developed (and later enforced) at a virtual interface between the porous bed and the channel flow. The condition is valid up to order two in terms of a small gauge factor, the ratio of microscopic to macroscopic length scales; it contains slip coefficients, plus surface and bulk permeability coefficients, which arise from the solution of microscale problems solved in a representative elementary volume. Using the effective boundary conditions, free of empirical parameters, direct numerical simulations are then performed in the channel, considering a few different porous substrates. The results, examined in terms of mean values and turbulence statistics, demonstrate the drag-reducing effects of porous substrates with streamwise-preferential alignment of the solid grains

    Further search for a neutral boson with a mass around 9 MeV/c2

    Get PDF
    Two dedicated experiments on internal pair conversion (IPC) of isoscalar M1 transitions were carried out in order to test a 9 MeV/c2 X-boson scenario. In the 7Li(p,e+e-)8Be reaction at 1.1 MeV proton energy to the predominantly T=0 level at 18.15 MeV, a significant deviation from IPC was observed at large pair correlation angles. In the 11B(d,n e+e-)12C reaction at 1.6 MeV, leading to the 12.71 MeV 1+ level with pure T=0 character, an anomaly was observed at 9 MeV/c2. The compatibility of the results with the scenario is discussed.Comment: 12 pages, 5 figures, 2 table

    Chirality-induced asymmetric magnetic nucleation in Pt/Co/AlOx ultrathin microstructures

    Get PDF
    The nucleation of reversed magnetic domains in Pt/Co/AlOx_{x} microstructures with perpendicular anisotropy was studied experimentally in the presence of an in-plane magnetic field. For large enough in-plane field, nucleation was observed preferentially at an edge of the sample normal to this field. The position at which nucleation takes place was observed to depend in a chiral way on the initial magnetization and applied field directions. An explanation of these results is proposed, based on the existence of a sizable Dzyaloshinskii-Moriya interaction in this sample. Another consequence of this interaction is that the energy of domain walls can become negative for in-plane fields smaller than the effective anisotropy field.Comment: Published version, Physical Review Letters 113, 047203 (2014
    corecore