1,357 research outputs found

    On the difference between proton and neutron spin-orbit splittings in nuclei

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    The latest experimental data on nuclei at 132^{132}Sn permit us for the first time to determine the spin-orbit splittings of neutrons and protons in identical orbits in this neutron-rich doubly-magic region and compare the case to that of 208^{208}Pb. Using the new results, which are now consistent for the two neutron-rich doubly magic regions, a theoretical analysis defines the isotopic dependence of the mean field spin-orbit potential and leads to a simple explicit expression for the difference between the spin-orbit splittings of neutrons and protons. The isotopic dependence is explained in the framework of different theoretical approaches.Comment: 8 pages, revte

    On the isospin dependence of the mean spin-orbit field in nuclei

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    By the use of the latest experimental data on the spectra of 133^{133}Sb and 131^{131}Sn and on the analysis of properties of other odd nuclei adjacent to doubly magic closed shells the isospin dependence of a mean spin-orbit potential is defined. Such a dependence received the explanation in the framework of different theoretical approaches.Comment: 52 pages, Revtex, no figure

    Development of the algorithm for aircraft control at inaccurate measurement of the state vector and variable accuracy parameter

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    A parametric method of the synthesis of control in the closed circuit, taking into account explicitly generalized error of the inertial module, is presented. The law of control in the form of analytical formulas is typically assigned to the control program and does not change during flight of an unmanned aerial vehicle. This decreases the capabilities of the autonomous flight control system to overcome control errors, which occur for various reasons. To verify assumptions about a possibility of improving the accuracy of an aerial vehicle control by the data of the strapdown inertial navigation system on a certain time interval of autonomous operation, the calculation experiment was conducted with the use of the developed software complex, simulating operation of the automatic flight control system. Parametrization of the law of control is considered as the main contribution (the outcome). Introduction of the parameter made it possible to decrease a negative impact of measurement errors and other disturbing factors on accuracy of reaching by the point of flight destination. Through computer modeling, it was shown that it is possible to decrease the impact of a generalized measurement error on generation of values of control functions by changing the value of the parameter. Analytical expressions for the estimation of accuracy of automatic control at the known generalized error of the inertial module and limited disturbing influences were obtained. After analyzing the influence of these factors on accuracy of the object control, a set of recommendations on selection of a variable parameter of synthesis of control depending on precision level of the sensors, used in the inertial module of measuring sensors, was generated.Розглянуто розв’язання термінальної задачі управління та синтезований параметризований закон управління в аналітичному вигляді, який залежить від змінного параметра глибини прогнозу. Досліджено особливості впливу величини параметра управління на точність досягнення кінцевої точки, дані рекомендації з вибору параметра для нівелювання помилки інерційних вимірювань. Синтез управління здійснюється методом переслідування ведучої точки за інформацією, отриманою інтегруванням вимірювань фактичного прискорення і містить помилку, характерну для акселерометрів

    Relativistic Nuclear Energy Density Functionals: adjusting parameters to binding energies

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    We study a particular class of relativistic nuclear energy density functionals in which only nucleon degrees of freedom are explicitly used in the construction of effective interaction terms. Short-distance (high-momentum) correlations, as well as intermediate and long-range dynamics, are encoded in the medium (nucleon density) dependence of the strength functionals of an effective interaction Lagrangian. Guided by the density dependence of microscopic nucleon self-energies in nuclear matter, a phenomenological ansatz for the density-dependent coupling functionals is accurately determined in self-consistent mean-field calculations of binding energies of a large set of axially deformed nuclei. The relationship between the nuclear matter volume, surface and symmetry energies, and the corresponding predictions for nuclear masses is analyzed in detail. The resulting best-fit parametrization of the nuclear energy density functional is further tested in calculations of properties of spherical and deformed medium-heavy and heavy nuclei, including binding energies, charge radii, deformation parameters, neutron skin thickness, and excitation energies of giant multipole resonances.Comment: 53 pages, 23 figures, accepted for publication in Physical Review

    Particulate dynamics in laser ablation plasmas

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