209 research outputs found

    ІНДИВІДУАЛЬНО-ПСИХОЛОГІЧНІ ОСОБЛИВОСТІ ПЕРЕЖИВАННЯ САМОТНОСТІ СЕРЕД МОЛОДІ

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    The paper deals with theoretical study of phenomenon of loneliness. The psychological features of teenagers’ loneliness experiencing are analyzed. The results of empiric research of interrelation feeling of loneliness with individual-psychological characteristics are presented.Исследованы теоретические аспекты феномена одиночества. Проанализированы особенности переживания одиночества в подростковом возрасте. Представлено эмпирическое исследование взаимосвязи чувства одиночества с индивидуально-психологическими характеристиками подростков.Досліджено теоретичні аспекти феномена самотності. Проаналізовано особливості переживання самотності у підлітковому віці. Представлено емпіричне дослідження взаємозв’язку відчуття самотності з індивідуально-психологічними характеристиками підлітків

    Observation of superluminal geometrical resonances in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions

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    We study Fiske steps in small Bi2Sr2CaCu2O8+x mesa structures, containing only few stacked intrinsic Josephson junctions. Careful alignment of magnetic field prevents penetration of Abrikosov vortices and facilitates observation of a large variety of high quality geometrical resonances, including superluminal with velocities larger than the slowest velocity of electromagnetic waves. A small number of junctions limits the number of resonant modes and allows accurate identification of modes and velocities. It is shown that superluminal geometrical resonances can be excited by subluminal fluxon motion and that flux-flow itself becomes superluminal at high magnetic fields. We argue that observation of high-quality superluminal geometrical resonances is crucial for realization of the coherent flux-flow oscillator in the THz frequency range

    Fiske Steps and Abrikosov Vortices in Josephson Tunnel Junctions

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    We present a theoretical and experimental study of the Fiske resonances in the current-voltage characteristics of "small" Josephson junctions with randomly distributed misaligned Abrikosov vortices. We obtained that in the presence of Abrikosov vortices the resonant interaction of electromagnetic waves, excited inside a junction, with the ac Josephson current manifests itself by Fiske steps in a current-voltage characteristics even in the absence of external magnetic field. We found that the voltage positions of the Fiske steps are determined by a junction size, but the Fiske step magnitudes depend both on the density of trapped Abrikosov vortices and on their misalignment parameter. We measured the magnetic field dependence of both the amplitude of the first Fiske step and the Josephson critical current of low-dissipative small NbNb based Josephson tunnel junctions with artificially introduced Abrikosov vortices. A strong decay of the Josephson critical current and a weak non-monotonic decrease of the first Fiske step amplitude on the Abrikosov vortex density were observed. The experimentally observed dependencies are well described by the developed theory.Comment: 21 pages, 7 figures, submitted to Physical Review

    Pb-207 chemical shielding in lead molybdate and lead chloride: The effects of temperature and lattice expansion

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    The analysis of heavy-metal solids with NMR spectroscopy provides a means of investigating the electronic environment through the dependence of the chemical shift on structure. We have investigated the relation of the 207Pb NMR isotropic chemical shift, span, and skew of a series of solid Pb(II) compounds to lattice parameters. Complementary relativistic spin−orbit density functional calculations on clusters such as PbI64- that model the local environment in the dihalides show a dependence of NMR properties on the local structure in good agreement with experimental results

    Quantum superposition of three macroscopic states and superconducting qutrit detector

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    Superconducting quantum coherent circuits have opened up a novel area of fundamental low-temperature science since they could potentially be the element base for future quantum computers. Here we report a quasi-three-level coherent system, the so-called superconducting qutrit, which has some advantages over a two-level information cell (qubit), and is based on the qutrit readout circuit intended to measure individually the states of each qubit in a quantum computer. The designed and implemented radio-frequency superconducting qutrit detector (rf SQUTRID) with atomic-size ScS-type contact utilizes the coherent-state superposition in the three-well potential with energy splitting Delta E_01/k_B=1.5 K at the 30th quantized energy level with good isolation from the electromagnetic environment. The reason why large values of Delta E_01 (and thus using atomic-size Nb-Nb contact) are required is to ensure an adiabatic limit for the quantum dynamics of magnetic flux in the rf SQUTRID.Comment: 9 pages, 5 figures, in v.3: text extended, inset in figure 1 (the device design) adde

    Effects of different fertilizer systems and hydrothermal factors on microbial activity in the chernozem in Ukraine

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    Groups of microorganisms in soils perform the role of global biogeochemical membrane which provides metabolism of substances and energy between the pedosphere, lithosphere, hydrosphere and living organisms. Сlimate change has resulted in a complex combination of unpredictable changeability of the environment, which is a serious test for the stability and productivity for the natural and anthropogenically transformed ecosystems. Changeability of the hydrothermal factors causes serious changes in the structure and metabolic activity of soil microorganisms, the quality and properties of soil. We studied the impact of hydrothermal factors on the content of carbon, microbial biomass and organic substance in deep chernozem of a natural ecosystem (fallow) and an agroecosystem under different systems of fertilization of winter wheat. A close relationship (r = 0.69–0.79) was determined between the content of microbial biomass in soil and hydrothermal factors (air temperature and moisture). Excessive drought and high parameters of air temperature led to decrease in the content of microbial biomass by 1.5–2.8 times compared to the years with optimum parameters of hydrothermal regime (HTC = 1.0). Leveling out the impact of high temperatures on the productivity of the soil microbiota occurs at a sufficient amount of moisture, and also available nutrients. Drought (HTC = 0.4) and excessive moisture (HTC = 2.0) following heightened air temperatures reduce the release of СО2 from soil. Fallow soil usually has a high content of microbial carbon in the organic compounds of soil (Сmic/Сorg was 2%). In the agroecosystem, there was recorded a decrease by 26–32% of the Сmic specific share in the content of the organic compound of the soil compared to the natural analogue. With organic and organic-mineral systems of fertilization, an increase in Сmic/Сorg parameter occurs and the soil parameters become close to the soil of a natural ecosystem. The calculated ecological coefficients of the orientation of microbial processes in soil indicate a possibility of a balanced functioning of the microbial group and introducing organic and organic-mineral fertilizers, creating optimum conditions for the productivity of winter wheat

    Features of exogenous development of Trichuris globulosa (Nematoda, Trichuridae)

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    Parasitic nematodes of the genus Trichuris Röderer, 1761 are hematophagous helminths, capable of parasitizing many different hosts including humans. The domestic and wild ruminants are hosts of several Trichuris species, with Trichuris globulosa (Linstow, 1901) one of the most prevalent parasites found in cattle. The exogenous stages of the helminth’s life cycle develop in the outer environment, and their activity and survival depend on the abiotic factors. Thus the aim of the work was to determine the influence of temperature on the rate and success of development of infectious eggs of T. globulosa in laboratory culture considering their morphological and metric changes. The results of experimental studies showed that the embryogenesis of T. globulosa eggs, cultured in laboratory conditions and obtained from gonads of female nematodes, occurs in six stages regardless of the temperature regime. At the same time, the rate of transition from one stage to another, the term for the formation of infectious eggs and their viability directly depends on the temperature of the external environment. At the optimal temperature for the development of T. globulosa eggs, 25 °C, 76.3% of eggs reached the mobile larva stage. A decrease in temperature to 20 °C and an increase to 30° C led to an increase in the egg mortality of up to 26% and 32%, respectively, and the viability of eggs decreased. Under such temperature conditions, 74% and 68% of eggs of Trichuris reached the mobile larva stage. With an increase in the culture temperature, the time of embryogenesis decreased and amounted to 56 days at 20 °C, 48 days at 25 °C, and 32 days at 30 °C. Depending on the temperature regime, the zygote stage lasted from the release of eggs from the gonads of female nematodes to 12 days, the stage of blastomere formation from 4 to 12 days, the stage of the bean-shaped embryo from 8 to 24 days, the stage of the tadpole embryo from 16 to 36 days, the stage of larval formation lasted from 16 to 48 days, the stage of mobile larva from days 20 to 56. The formation of the infectious T. globulosa egg from a non-infectious one is shown in an experiment to include the metric changes confirmed by metric indicators. Mature eggs with a mobile larva are shorter and wider, with shorter and narrower plugs and a thinner shell than eggs at the zygote stage. The obtained research results on the influence of temperature on the exogenous development of Trichuris globulosa will make it possible to predict the epizootic situation of trichurosis in animal husbandry, as well as take timely measures to arrest the embryonic stages of nematode development in the external environment

    Laser Scanning Microscopy of HTS Films and Devices

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    The work describes the capabilities of Laser Scanning Microscopy (LSM) as a spatially resolved method of testing high_Tc materials and devices. The earlier results obtained by the authors are briefly reviewed. Some novel applications of the LSM are illustrated, including imaging the HTS responses in rf mode, probing the superconducting properties of HTS single crystals, development of twobeam laser scanning microscopy. The existence of the phase slip lines mechanism of resistivity in HTS materials is proven by LSM imaging.Comment: 17 pages, 21 figures, Submitted to Fizika Nizkikh Temperatur (Low Temperature Physics

    Fractional ac Josephson effect in unconventional superconductors

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    For certain orientations of Josephson junctions between two p_x-wave or two d-wave superconductors, the subgap Andreev bound states produce a 4pi-periodic relation between the Josephson current I and the phase difference phi: I ~ sin(phi/2). Consequently, the ac Josephson current has the fractional frequency eV/h, where V is the dc voltage. In the tunneling limit, the Josephson current is proportional to the first power (not square) of the electron tunneling amplitude. Thus, the Josephson current between unconventional superconductors is carried by single electrons, rather than by Cooper pairs. The fractional ac Josephson effect can be observed experimentally by measuring frequency spectrum of microwave radiation from the junction.Comment: 8 pages, 3 figures, RevTEX 4; v2. - minor typos corrected in proof

    Recent changes in shelf hydrography in the Siberian Arctic : potential for subsea permafrost instability

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    Summer hydrographic data (1920–2009) show a dramatic warming of the bottom water layer over the eastern Siberian shelf coastal zone (<10 m depth), since the mid-1980s, by 2.1°C. We attribute this warming to changes in the Arctic atmosphere. The enhanced summer cyclonicity results in warmer air temperatures and a reduction in ice extent, mainly through thermodynamic melting. This leads to a lengthening of the summer open-water season and to more solar heating of the water column. The permafrost modeling indicates, however, that a significant change in the permafrost depth lags behind the imposed changes in surface temperature, and after 25 years of summer seafloor warming (as observed from 1985 to 2009), the upper boundary of permafrost deepens only by ∼1 m. Thus, the observed increase in temperature does not lead to a destabilization of methane-bearing subsea permafrost or to an increase in methane emission. The CH4 supersaturation, recently reported from the eastern Siberian shelf, is believed to be the result of the degradation of subsea permafrost that is due to the long-lasting warming initiated by permafrost submergence about 8000 years ago rather than from those triggered by recent Arctic climate changes. A significant degradation of subsea permafrost is expected to be detectable at the beginning of the next millennium. Until that time, the simulated permafrost table shows a deepening down to ∼70 m below the seafloor that is considered to be important for the stability of the subsea permafrost and the permafrost-related gas hydrate stability zone
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