Anomalous Proximity Effect in Underdoped YBaCuO Josephson Junctions

Josephson junctions were photogenerated in underdoped thin films of the YBa$_2$Cu$_3$O$_{6+x}$ family using a near-field scanning optical microscope. The observation of the Josephson effect for separations as large as 100 nm between two wires indicates the existence of an anomalously large proximity effect and show that the underdoped insulating material in the gap of the junction is readily perturbed into the superconducting state. The critical current of the junctions was found to be consistent with the conventional Josephson relationship. This result constrains the applicability of SO(5) theory to explain the phase diagram of high critical temperature superconductors.Comment: 11 pages, 4 figure

Экономическая оценка применения иммунокорригирующих препаратов для профилактики частых респираторных инфекций и их осложнений у детей младшего школьного возраста

the economic analysis of influence of various immunocorrective remedies on the frequency of respiratory infections at children of younger school age was made. It was revealed that carrying out the preventive immunocorrection including lysates of bacteria or gljukozaminilmuramildipeptid in combination with a vitamin and mineral complex, leads to statistically significant decrease in frequency of respiratory infections and considerable decrease direct and indirect cost on treatment of respiratory infectious diseases. Preventive use Echinacea purpurea, azoksimer bromide or interferon alpha 2b in combination with a vitamin and mineral complex statistically significantly reduces the frequency of respiratory infections and slightly cuts direct and indirect costs on their treatment.выполнен экономический анализ эффективности применения различных иммунокорригирующих препаратов на частоту респираторных инфекций у часто болеющих детей младшего школьного возраста. Выявлено, что проведение профилактической иммунокоррекции, включающей лизаты бактерий или глюкозаминилмурамилдипептид в сочетании с витаминно-минеральным комплексом, приводит к статистически значимому снижению частоты респираторных инфекций и значительному снижению прямых и косвенных затрат на лечение инфекционных заболеваний дыхательных путей. Профилактическое использование сока пурпурной травы эхинацеи, азоксимера бромида или интерферона альфа-2b в сочетании с витаминно-минеральным комплексом статистически значимо снижает частоту респираторных инфекций и незначительно снижает прямые и косвенные расходы на их лечени

Strongly Enhanced Current Densities in Superconducting Coated Conductors of YBa2Cu3O7-x + BaZrO3

There are numerous potential applications for superconducting tapes, based on YBa2Cu3O7-x (YBCO) films coated onto metallic substrates. A long established goal of more than 15 years has been to understand the magnetic flux pinning mechanisms which allow films to maintain high current densities out to high magnetic fields. In fact, films carry 1-2 orders of magnitude higher current densities than any other form of the material. For this reason, the idea of further improving pinning has received little attention. Now that commercialisation of conductors is much closer, for both better performance and lower fabrication costs, an important goal is to achieve enhanced pinning in a practical way. In this work, we demonstrate a simple and industrially scaleable route which yields a 1.5 to 5-fold improvement in the in-field current densities of already-high-quality conductors

Elastic-to-plastic crossover below the peak effect in the vortex solid of YBa2Cu3O7 single crystals

We report on transport and ac susceptibility studies below the peak effect in twinned YBa2Cu3O7 single crystals. We find that disorder generated at the peak effect can be partially inhibited by forcing vortices to move with an ac driving current. The vortex system can be additionally ordered below a well-defined temperature where elastic interactions between vortices overcome pinning-generated stress and a plastic to elastic crossover seems to occur. The combined effect of these two processes results in vortex structures with different mobilities that give place to history effects.Comment: 4 pages, 4 figures. Published in PRB Rapid Comm., February 1, 200

Selective mass enhancement close to the quantum critical point in BaFe₂(As₁₋ₓ Pₓ )₂

A quantum critical point (QCP) is currently being conjectured for the BaFe₂(As₁₋ₓ Pₓ )₂ system at the critical value xc ≈ 0.3. In the proximity of a QCP, all thermodynamic and transport properties are expected to scale with a single characteristic energy, given by the quantum fluctuations. Such a universal behavior has not, however, been found in the superconducting upper critical field Hc2. Here we report Hc2 data for epitaxial thin films extracted from the electrical resistance measured in very high magnetic fields up to 67 Tesla. Using a multi-band analysis we find that Hc₂ is sensitive to the QCP, implying a significant charge carrier effective mass enhancement at the doping-induced QCP that is essentially band-dependent. Our results point to two qualitatively different groups of electrons in BaFe₂(As₁₋ₓ Pₓ )₂ . The first one (possibly associated to hot spots or whole Fermi sheets) has a strong mass enhancement at the QCP, and the second one is insensitive to the QCP. The observed duality could also be present in many other quantum critical systems

Observation of narrow baryon resonance decaying into pKs0pK^0_s in pA-interactions at 70GeV/c70 GeV/c with SVD-2 setup

SVD-2 experiment data have been analyzed to search for an exotic baryon state, the $\Theta^+$-baryon, in a $pK^0_s$ decay mode at $70 GeV/c$ on IHEP accelerator. The reaction $pA \to pK^0_s+X$ with a limited multiplicity was used in the analysis. The $pK^0_s$ invariant mass spectrum shows a resonant structure with $M=1526\pm3(stat.)\pm 3(syst.) MeV/c^2$ and $\Gamma < 24 MeV/c^2$. The statistical significance of this peak was estimated to be of $5.6 \sigma$. The mass and width of the resonance is compatible with the recently reported $\Theta^+$- baryon with positive strangeness which was predicted as an exotic pentaquark ($uudd\bar{s}$) baryon state. The total cross section for $\Theta^+$ production in pN-interactions for $X_F\ge 0$ was estimated to be $(30\div120) \mu b$ and no essential deviation from A-dependence for inelastic events $(\sim A^{0.7})$ was found.Comment: 8 pages, 7 figures, To be submitted to Yadernaya Fizika. v3-v5 - Some references added, minor typos correcte

Dynamics and Radiation of Young Type-Ia Supernova Remnants: Important Physical Processes

We examine and analyze the physical processes that should be taken into account when modeling young type-Ia SNRs, with ages of several hundred years. It is shown, that energy losses in the metal-rich ejecta can be essential for remnants already at this stage of evolution. The influence of electron thermal conduction and the rate of the energy exchange between electrons and ions on the temperature distribution and the X-radiation from such remnants is studied. The data for Tycho SNR from the XMM-Newton X-ray telescope have been employed for the comparison of calculations with observations.Comment: 19 pages, 8 figure