54 research outputs found

    The temperature fields in electrically heated wires at crisis of boiling

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    The self-organization processes take place in several phenomena and physical objects and in particular they arise in metals in conditions of charge transfer. At liquid helium temperature in conditions of the increase of direct current flowing through bismuth, indium and tungsten there arise unstabilities of charge carries flux and this process exhibits itself in electromagnetic oscillations generation. This instability the authors refer to the mutual influence of the current flowing through the sample and magnetic field of the current. With this heat flux density through the sample’s surfaces didn’t exceed 0.1 W/sm2. Such a value of heat flux is сlose to the first boiling crisis but the author state that the nature of these phenomena is no case is connected with the heat removal specific features

    Alternating-Spin Ladders in a Magnetic Field: New Magnetization Plateaux

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    We study numerically the formation of magnetization plateaux with the Lanczos method in 2-leg ladders with mixed spins of magnitudes (S1,S2)=(1,1/2)(S_1,S_2)=(1,1/2) located at alternating positions along the ladder and with dimerization Îł\gamma. For interchain coupling Jâ€Č>0J'>0 and Îł=0\gamma=0, we find normalized plateaux at m=1/3m=1/3 starting at zero field and m=1m=1 (saturation), while when γ≠0\gamma \ne 0 is columnar, another extra plateau at m=2/3m=2/3 shows up. For Jâ€Č<0J'<0, when Îł<Îłc(Jâ€Č)\gamma<\gamma_c(J') we find no plateau while for Îł>Îłc(Jâ€Č)\gamma>\gamma_c(J') we find four plateaux at m=0,1/3,2/3,1m=0,1/3,2/3,1. We also apply several approximate analytical methods (Spin Wave Theory, Low-Energy Effective Hamiltonians and Bosonization) to understand these findings and to conjeture the behaviour of ferrimagnetic ladders with a bigger number of legs.Comment: REVTEX file, 7 pages, 6 eps Figure

    Josephson effect in double-barrier superconductor-ferromagnet junctions

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    We study the Josephson effect in ballistic double-barrier SIFIS planar junctions, consisting of bulk superconductors (S), a clean metallic ferromagnet (F), and insulating interfaces (I). We solve the scattering problem based on the Bogoliubov--de Gennes equations and derive a general expression for the dc Josephson current, valid for arbitrary interfacial transparency and Fermi wave vectors mismatch (FWVM). We consider the coherent regime in which quasiparticle transmission resonances contribute significantly to the Andreev process. The Josephson current is calculated for various parameters of the junction, and the influence of both interfacial transparency and FWVM is analyzed. For thin layers of strong ferromagnet and finite interfacial transparency, we find that coherent (geometrical) oscillations of the maximum Josephson current are superimposed on the oscillations related to the crossover between 0 and π\pi states. For the same case we find that the temperature-induced 0−π0-\pi transition occurs if the junction is very close to the crossovers at zero temperature.Comment: 13 pages, 6 figure

    Genetic variation of RFXANK gene in Stavropol sheep breed

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    Using of NimbleGen sequencing technology for detection of polymorphisms RFXANK gene in Stavropolsheep breed, we found 20 SNPs. That is, two SNP in exons - c.63C>A (non synonymous) in exon II and c.498G>A in exon VI (synonymous). Others SNP is in introns: c.-343T>C, c.- 111T>G, c.187+328G>A, c.338-94G>A, c.632–124G>A, c.713-82G>A, c.187+62G>A, c.188-588G>C, c.188- 127C>T, c.565-44A>G, c.712+309C>T, c.712+354C>T, c.712+309C>T, c.187+394C>T, c.187+469A>G, c.187+71G>C, c.188-670A>G, c.713-107G>T. Some of them are presented together

    Rational Diversification of a Promoter Providing Fine-Tuned Expression and Orthogonal Regulation for Synthetic Biology

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    Yeast is an ideal organism for the development and application of synthetic biology, yet there remain relatively few well-characterised biological parts suitable for precise engineering of this chassis. In order to address this current need, we present here a strategy that takes a single biological part, a promoter, and re-engineers it to produce a fine-graded output range promoter library and new regulated promoters desirable for orthogonal synthetic biology applications. A highly constitutive Saccharomyces cerevisiae promoter, PFY1p, was identified by bioinformatic approaches, characterised in vivo and diversified at its core sequence to create a 36-member promoter library. TetR regulation was introduced into PFY1p to create a synthetic inducible promoter (iPFY1p) that functions in an inverter device. Orthogonal and scalable regulation of synthetic promoters was then demonstrated for the first time using customisable Transcription Activator-Like Effectors (TALEs) modified and designed to act as orthogonal repressors for specific PFY1-based promoters. The ability to diversify a promoter at its core sequences and then independently target Transcription Activator-Like Orthogonal Repressors (TALORs) to virtually any of these sequences shows great promise toward the design and construction of future synthetic gene networks that encode complex “multi-wire” logic functions

    The Flux-Line Lattice in Superconductors

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    Magnetic flux can penetrate a type-II superconductor in form of Abrikosov vortices. These tend to arrange in a triangular flux-line lattice (FLL) which is more or less perturbed by material inhomogeneities that pin the flux lines, and in high-TcT_c supercon- ductors (HTSC's) also by thermal fluctuations. Many properties of the FLL are well described by the phenomenological Ginzburg-Landau theory or by the electromagnetic London theory, which treats the vortex core as a singularity. In Nb alloys and HTSC's the FLL is very soft mainly because of the large magnetic penetration depth: The shear modulus of the FLL is thus small and the tilt modulus is dispersive and becomes very small for short distortion wavelength. This softness of the FLL is enhanced further by the pronounced anisotropy and layered structure of HTSC's, which strongly increases the penetration depth for currents along the c-axis of these uniaxial crystals and may even cause a decoupling of two-dimensional vortex lattices in the Cu-O layers. Thermal fluctuations and softening may melt the FLL and cause thermally activated depinning of the flux lines or of the 2D pancake vortices in the layers. Various phase transitions are predicted for the FLL in layered HTSC's. The linear and nonlinear magnetic response of HTSC's gives rise to interesting effects which strongly depend on the geometry of the experiment.Comment: Review paper for Rep.Prog.Phys., 124 narrow pages. The 30 figures do not exist as postscript file
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