[en] In the present work the phenomenon of fine structure in the region of the isoscalar giant quadrupole resonance in a number of heavy and medium-heavy nuclei is systematically investigated for the first time. High energy-resolution inelastic proton scattering experiments were carried out in September-October 2001 and in October 2003 at the iThemba LABS cyclotron facility in South Africa with an incident proton energy of 200 MeV. The obtained data with the energy resolution of triangle E<50 keV FWHM revealed the appearance of fine structure in all the nuclei studied (⁵⁸Ni,⁸⁹Y,⁹⁰Zr,¹²⁰Sn,¹⁴²Nd,¹⁶⁶Er,²⁰⁸Pb), thereby establishing the global character of this phenomenon. Fine structure can be described using characteristic energy scales, appearing as a result of the decay of collective modes towards the compound nucleus through a hierarchy of couplings to complex degrees of freedom. For the extraction of the characteristic energy scales from the spectra an entropy index method and a novel technique based on the wavelet analysis are utilized. The global analysis of available data shows the presence of three groups of scales, according to their values. To the first group belong the scales with the values around and below 100 keV, which were detected in all the nuclei studied. The second group contains intermediate scales in the range of 100 keV to 1 MeV. These scales show large variations depending on the nuclear structure of the nucleus. The largest scales above 1 MeV are classified to the third group, describing the global structure of the resonance (the width). The interpretation of the observed scales is realized via the comparison with microscopic model calculations including the coupling of the initial one-particle-one-hole excitations to more complex configurations. A qualitative agreement of the experimentally observed scales with those obtained from the theoretical predictions supports the suggestion of the origin of fine structure from the coupling to the two-particle-two-hole states. However, quantitatively, large deviations are observed for the values of scales given by different models. A more detailed study of the physical nature of extracted scales is provided with the help of the quasiparticle-phonon model and extended time-dependent Hartree-Fock model, which allow to separate the contributions from different damping mechanisms. The main source of the observed scales is identified to arise from the collective damping mechanism, which is the coupling to low-lying surface vibrations. This conforms with the doorway picture of the damping of giant resonances. At the same time, through the comparison with a model of stochastic coupling to many particle-hole states some generic features of the non-collective damping mechanism could be extracted. (orig.)

[en] Automatic translation: The stations for the study of the processes of horizontal and vertical migration of radionuclides near the villages of Kopachi (at a distance of 5-6 km from the emergency unit) and Zalesye (18-20 km) were organized by the Ukrainian Research Institute of Agricultural Radiology and the Ukrainian Research Institute of Soil Protection from Erosion in 1987 from the purpose of conducting scientific research under the program of integrated radiological monitoring of soils in the exclusion zone.

[en] The range of observations on the slopes of the reclamation canals in the Chernobyl Exclusion Zone as well as laboratory experiments over the monoliths collected there allow to clarify some features of ⁹⁰Sr distribution in the soil profiles after the floods of different duration. The leaching rates are compared with the radionuclides' distribution versus a depth in the monoliths, relationships between the grain sizes in the separate layers, changes of pH and specifics of the chemical composition of the solution. Observed data allowed to calculate the thickness of the effective mass exchange layer under the static conditions. It made up to 7-12 cm of the soil in dependence on soil density and the height of the capillary edgings ascending. Maximum leaching of ⁹⁰Sr from soil to the surface water took place during the sinking of the highest slope marks elevation. When the rate of fission products release from the fuel matrix is higher than the rate of their water removal from soils ⁹⁰Sr accumulation has been took place in the pore space of the soils of zone of suspended water. In the lab experiments ⁹⁰Sr concentration in the eluate has increased during 42 days. About 6% of ⁹⁰Sr in the monolith were transferred into the water phase. Concentration of ⁹⁰Sr and ¹³⁷Cs in the water phase decreased after 57 day of experiment. Momentary coefficient of washout and integrated rate of radionuclides leaching was calculated taking into account changes of the thickness of layer of effective mass exchange during the experiment. Some portion of leached nuclides was bound in the suspended organic matter of aquatic life origin. Content of organic dredge in water phase increased during the all course of experiment. Share of ⁹⁰Sr that was sorbed by dredge increased from 11 to 87% of its total activity in the water phase. Thus radionuclides leaching from the slopes of reclamation canals are the major source of surface waters secondary contamination. (author)

[en] To adjust the stabilization systems that ensure the operation of the angular position or rate sensor based on the effect of nuclear magnetic resonance, it is required to choose the criteria for the quality assessing of sensor’s operation. The article presents the criteria of the quality of the angular sensor operating as a self-oscillation system. It is shown that the accuracy of the angular sensor increases when the proposed criteria are met. (paper)

[en] Voronoi-Dirichlet (VD) polyhedra and the intersecting spheres method were used to perform crystal-chemical analysis of 218 compounds containing 306 crystallographic types of cerium atoms in CeO_n coordination polyhedra. With respect to oxygen atoms, the coordination numbers (CNs) of Ce(IV) atoms are 6-10 and 12 and those of Ce(III) atoms are 4 and 6-12. For a fixed valence state of a cerium atom, the volume of its VD polyhedron is virtually independent of the CN, although the Ce-O bond lengths change by 0.8 A. In going from Ce(IV) to Ce(III), the volume of their VD polyhedra increases, on average, by 2.1 A³. The characteristics of the VD polyhedra of cerium atoms can be used for determining their valence states in crystals structures

No abstract available

[en] In this paper, issues related to the optimization of superconducting passive interconnects are discussed. Results of the microwave optimization of bends, via connections and crossings of superconducting microstrip lines (SMSLs) are reported. The optimum design of the SMSL cross gives more than 95% of transmission and can be well used in a two-bus cross design with up to 14 signal wires. The results have been confirmed by time-domain simulations and measurements

[en] For more than a century, physicists have searched for a unique and general form for the force density that an electromagnetic field imposes on a medium. The existing equations for this quantity, obtained, e.g., by Minkowski, Einstein and Laub, Abraham and Helmholtz, are manifestly different and, as such, give different predictions in some particular physical situations. The cases of real media with dispersion, dissipation and nonlinearities as well as materials with optical gain have not been addressed much. Here we present an unambiguous general equation for the force density expressed in terms of a new energy-momentum tensor of the field. The equation can be applied to almost any natural or designed material. We show how the results obtained by Minkowski, Helmholtz, Einstein and Laub, and Abraham appear as special cases of this general treatment. Surprisingly, our result turns out to be physically very close to the almost forgotten result of Einstein and Laub.

[en] We have designed and experimentally verified a test bench for high frequency testing of rapid single-flux-quantum (RSFQ) circuits. This test bench uses an external tunable clock signal that is stable in amplitude, phase and frequency. The high frequency external clock reads out the clock pattern stored in a long shift register. The clock pattern is consequently shifted out at high speed and split to feed both the circuit under test and an additional shift register in the test bench for later verification at low speed. This method can be employed for reliable high speed verification of RSFQ circuit operation, with use of only low speed read-out electronics. The test bench consists of 158 Josephson junctions and the occupied area is 3300 x 660 μm². It was experimentally verified up to 33 GHz with ± 21.7% margins on the global bias supply current

[en] A precise measurement of the proton charge radius is an old, but still open problem. Interest is renewed by extremely precise Lamb Shift measurements requiring higher-order QED corrections for their interpretation depending on the proton charge radius. Existing measurements show a considerable scattering of results. A new precision experiment using elastic electron scattering is now in preparation at the S-DALINAC, where backscattered protons instead of the electrons will be measured. This new method has many advantages. For example, one can measure range of momentum transfers with a single setup, thereby avoiding normalization problems. Recent test measurements demonstrate the feasibility of such a kind of experiment, but at the same time show several problems to be solved first. Preliminary results and conclusions are discussed. (orig.)