524 research outputs found

    Observation of Stochastic Resonance in Percolative Josephson Media

    Get PDF
    Measurements of the electrical response of granular Sn-Ge thin films below the superconducting transition temperature are reported. The addition of an external noise to the magnetic field applied to the sample is found to increase the sample voltage response to a small externally applied ac signal. The gain coefficient for this signal and the signal-to-noise ratio display clear maxima at particular noise levels. We interpret these observations as a stochastic resonance in the percolative Josephson media which occurs close to the percolation threshold.Comment: 4 pages, 5 figure

    Calculation of the magnetic field in the active zone of a hysteresis clutch

    Get PDF
    The initial distribution of magnetic induction in the armature stationary was calculated relative to the polar system of a hysteresis clutch. Using several assumptions, the problem is reduced to calculating the static magnetic field in the ferromagnetic plate with finite and continuous magnetic permeability placed in the air gap between two identical, parallel semiconductors with rack fixed relative to the tooth or slot position

    Dynamic aperture limitation in e+ee^+e^- colliders due to synchrotron radiation in quadrupoles

    Full text link
    In a lepton storage ring of very high energy (e.g. in the e+ee^+e^- Higgs factory) synchrotron radiation from quadrupoles constrains transverse dynamic aperture even in the absence of any magnetic nonlinearities. This was observed in tracking for LEP and the Future Circular e+ee^+e^- Collider (FCC-ee). Here we describe a new mechanism of instability created by modulation of the particle energy at the double betatron frequency by synchrotron radiation in the quadrupoles. Energy modulation varies transverse focusing strength at the same frequency and creates a parametric resonance of the betatron oscillations with unusual properties. It occurs at arbitrary betatron frequency (the resonant detuning is always zero) and the magnitude of the parameter modulation of the betatron oscillation (strength of the resonance driving term) depends on the oscillation amplitude. Equilibrium between the radiation damping and the resonant excitation gives the boundary of the stable motion. Starting from 6d equations of motion we derive and solve the relevant differential equation describing the resonance, and show good agreement between analytical results and numerical simulation

    Dynamics of the penetration boundaries of solar protons during a strong magnetic storm

    Get PDF
    The variations in the equatorial penetration boundary of solar protons with E sub p = 0.9 to 8.0 MeV during a strong magnetic storm of April 3 to 5, were analyzed. The dynamics of this boundary is compared with the dynamics of the outer trapping boundary of electrons with E sub e = - 0.3 to 0.6 MeV. The solar-proton penetration and the structure of the real magnetic field are studied. The unique data on the thin structure of development of a magnetospheric substorm were obtained for the first time

    Vibronic interaction in crystals with the Jahn-Teller centers in the elementary energy bands concept

    Full text link
    The order-disorder type phase transition caused by the vibronic interaction (collective Jahn-Teller effect) in a monoclinic CuInP2_2S6_6 crystal is analyzed. For this purpose, a trigonal protostructure model of CuInP2_2S6_6 is created, through a slight change in the crystal lattice parameters of the CuInP2_2S6_6 paraelectric phase. In parallel to the group-theoretical analysis, the DFT-based {\it ab initio} band structure calculations of the CuInP2_2S6_6 protostructure, para-, and ferriphases are performed. Using the elementary energy bands concept, a part of the band structure from the vicinity of the forbidden energy gap, which is created by the dd-electron states of copper, has been related with a certain Wyckoff position where the Jahn-Teller's centers are localized. A construction procedure of the vibronic potential energy matrix is generalized for the case of crystal using the elementary energy bands concept and the group theoretical method of invariants. The procedure is illustrated by the creation of the adiabatic potentials of the Γ5\Gamma_5-Γ5\Gamma_5 vibronic coupling for the protostructure and paraphase of the CuInP2_2S6_6 crystal. A structure of the obtained adiabatic potentials is analyzed, followed by conclusions on their transformation under a phase transition and the discussion on the possibility for the spontaneous polarization to arise in this crystal.Comment: 17 pages, 7 figure

    Singularities of training personnel in the family economics and family business at the current stage of development of market relations

    Get PDF
    Transition of Russia to the development of market relations turned out to be an incentive motive for developing the basic concepts of the family economics and family business, a discovery of the opportunity for many Russian citizens to be engaged in entrepreneurship, which has formerly been inaccessible for them. The modern changes taking place in Russia and abroad raise new requirements for training the youths, for conscious active participation in various spheres of the socio-economic life of the society, in development of family businesses, and improvement of their efficiency. It should be noted that the problems of professional training of young people at higher education institutions as members of households in participation in the family business, formation of qualities of a future entrepreneur, and the entrepreneurial activity in the family business are actively considered and implemented in developed countries, while Russia does not virtually take part in this process. The main cause of failure in the family business is lack of competence, skills, and leadership qualities, as well as a set of competences needed for a successful business. © 2015 Canadian Center of Science and Education. All rights reserved

    Особенности строения биомедицинских сплавов Ti-Nb, полученных электродуговой плавкой и селективным лазерным сплавлением

    Get PDF
    Выявлено, что при электродуговой плавке и селективном лазерном сплавлении в сплаве Ti-Nb имеет место ликвация компонентов. На участках, обогащенных Nb образуется [beta]-фаза, на участках, обедненных Nb - [alpha]''-фаза. Для устранения неоднородности фазового и элементного состава рекомендуется повысить содержание Nb в сплаве до 45 мас. %

    Approximation of complex, multiparameter, essentially nonlinear, dynamic relationships based on genetic algorithms

    Get PDF
    The work is focused on usage of genetic algorithms to get more precise approximation of complex and essentially nonlinear dynamic relationships. The algorithms precision was measured based on the model of stock market index prediction

    Modified hybrid genetic algorithm of discreet optimization problems

    Get PDF
    The goal objective is to improve the efficiency of solving discrete optimization problems. The proposed method refers to the “fast” methods and was named the “Local genetic method”. The peculiarity of this method is that the chromosomes do not encode the whole solution, but only a small part of the plan. Therefore, the method allows us introducing unary and binary operations that take into account the specific nature of the problem. The important feature of the method is the non-deterministic nature of the computation, which is due to the internal parallelism of computations and is expressed in the asynchronous action of various local strategies. In terms of speed, the proposed method in a number of experiments outperformed the traditional algorithm by more than 10 times and always found the best solution. The nature of the approximation to the optimum for these algorithms remained unchanged when solving any test cases
    corecore