[en] A system was developed for bunch-by-bunch detection of transverse proton and antiproton coherent oscillations based on the signal from a single beam-position monitor (BPM) located in a region of the ring with large amplitude functions. The signal is digitized over a large number of turns and Fourier-analyzed offline with a dedicated algorithm. To enhance the signal, the beam is excited with band-limited noise for about one second, and this was shown not to significantly affect the circulating beams even at high luminosity. The system is used to measure betatron tunes of individual bunches and to study beam-beam effects. In particular, it is one of the main diagnostic tools in an ongoing study of nonlinear beam-beam compensation studies with Gaussian electron lenses. We present the design and operation of this tool, together with results obtained with proton and antiproton bunches.

[en] The recent results for a superconducting single-photon counter are presented. The detection mechanism of the photon counter is based on the combined action of the hot-spot formation after photon absorption and the subsequent current-assisted formation of a normal domain in a thin and narrow superconducting strip. Dark count rates caused by fluctuations of the superconducting order parameter as a function of the applied current are discussed

[en] By now more than 100 dual-purpose packaging sets TUK-108/1 are in operation in the mode of interim storage and transportation of SNF from decommissioned nuclear powered submarines (NPSs). In accordance with certificate, spent fuel is stored in TUK-108/1 on the premises of plants involved in NPS dismantlement for 2 years, whereupon it is transported for processing to PO Mayak. At one Far Eastern plant Zvezda involved in NPS dismantlement there arose a complicated situation due to necessity to extend period of storage of SNF in TUK-108/1. To ensure safety over a longer period of storage of SNF in TUK-108/1 it is essential to modify conditions of storage by removing of residual water and filling the inner cavity of the cask with an inert gas. This report describes key issues of cask drying technology, justification of terms of dry storage of naval SNF in TUK- 108/1 and RBMK-1000 SNF in UKhK-109, design features of the mobile drying facility, results of operation of the pilot facility at the Far Eastern plant Zvezda and cold testing on the shop factory for Leningrad NPP. (author)

[en] Different modes of man-machine interface organization in expert systems (ES) are discussed. Some of the points of consideration are similar to other man-machine systems, and some are specific ES interface problems, such as knowledge formalization and acquisition, different modes of dialogue with different kinds of terminal users as well as problems related to explanation. All discussions are based on personal experience in ES project developments in different nuclear application areas. (author). 5 refs

[en] Electronic devices based on semiconductor heterostructures are used extensively in different areas of science and technology. One of the semiconductor materials most promising for operation under the conditions of external attacks is silicon carbide. The heterostructures SiC created by the layers of nanocrystalline SiC of different polytypes were grown by the method of direct ion deposition. The aim of the present work was to study the mechanisms of charge transfer in the nanocrystalline heteropolytype SiC films, deposited on leucosapphire single-crystalline substrates. The average size of the nanocrystals in the heterostructures SiC was 5 - 10 nm. To clarify the mechanisms of charge transport in the obtained films there was studied the temperature dependence of their electrical conductivity σ. The electrical measurements were performed by the four-contact method at direct current. The electrical conductivity of the heteropolytype film is the sum of the conductivity values of the parallel channels σ = σ₁ + σ₂ + σ_hj, where σ and σ₂ are the conductivity of the monopolytype regions which form the heteropolytype film, σ_hj, the heterojunction conductivity. It was found that main contribution to the electrical conductivity of the films belongs to the contact region of the heterojunction, i.e. condition σ₁ + σ₂ << σ_hj is fulfilled. This is due to the fact that in the contact region the charge transfer is realized by the multistep tunneling via discrete energy levels with close energies. These discrete energy states arise in the forbidden band due to the dimensional quantization. It was established that the characteristic energy of the charge transfer process is of the order 10 meV. (author)

[en] The existence of spatially localized nonlinear modes in carbon nanotubes with different chiralities is discussed, and it is demonstrated that in nanotubes with chirality index (m,0) three types of localized modes can exist, namely longitudinal, radial, and twisting nonlinear localized modes. It is demonstrated that only the nonlinear modes associated with the twisting oscillations are nonradiating modes, and they exist in the frequency gaps of the linear spectrum. The geometry of carbon nanotubes with the index (m,m) allows only the existence of broad radial breathers in a narrow spectral range

[en] We show that resonant coupling of coherent electron Bloch oscillations to longitudinal optical phonons in a wide-miniband semiconductor superlattice induces a unidirectional transient electron current in the system. This effect has a profound analogy to the DC Fiske effect observed when a superconductor Josephson junction or a superfluid weak link is coupled, respectively, to an electromagnetic or acoustic resonator. In the ultrafast Fiske effect, the coupling opens an elastic rectifying channel which exists only during the coherence time of the electron wave packets involved. In the considered ultrafast coupling effect, the longitudinal optical phonons in the superlattice play the role of the resonator coupled to the free damped electron Bloch oscillations, via both their amplitude and phase. We also show that similar unidirectional transient current, but with the opposite sign, is induced by non-resonant coupling of electron Bloch oscillations to coherent electron plasma oscillations. This unidirectional transient current can probably explain the origin, the sign and the carrier-density dependence of the self-induced coherent unidirectional current, which was observed in an undoped biased semiconductor superlattice with photo-excited carriers

[en] A simplified model describing the steady state of a helicon discharge in a low-pressure plasma is considered. The electron Langmuir frequency of the plasma produced by the discharge is shown to be much higher than the electron gyrofrequency. It is found that the gas medium is ionized and the electrons are heated primarily by the extraordinary mode. The calculated electron density depends nonmonotonically on the magnetic field, in agreement with the results of numerous experiments

[en] It is shown that the Dirac equation for free particle can be considered as a description of specific distortion of the space euclidean geometry (space topological defect). This approach is based on possibility of interpretation of the wave function as vector realizing representation of the fundamental group of the closed topological space-time 4-manifold. Mass and spin appear to be topological invariants. Such concept explains all so called “strange” properties of quantum formalism: probabilities, wave-particle duality, nonlocal instantaneous correlation between noninteracting particles (EPR-paradox) and so on. Acceptance of suggested geometrical concept means rejection of atomistic concept where all matter is considered as consisting of more and more small elementary particles. There is no any particles a priori, before measurement: the notions of particles appear as a result of classical interpretation of the contact of the region of the curved space with a device.

[en] The thermal boundary resistance at the YBaCuO thin film/Al₂O₃ substrate interface was investigated. The transparency for thermal phonons incident on the interface as well as for phonons moving from the substrate was determined. We have measured a transient voltage response of current-biased films to continuously modulated radiation. The observed knee in the modulation frequency dependence of the response reflects the crossover from the diffusion regime to the contact resistance regime of the heat transfer across the interface. The values of transparency were independently deduced both from the phonon escape time and from the time of phonon return to the film which were identified with peculiarities in the frequency dependence. The results are much more consistent with the acoustic mismatch theory than the diffuse mismatch model. 11 refs., 2 figs