217 research outputs found

    Photoinduced Magnetic Transitions and Excitonic Order Enhancement in Spin Crossover Strongly Correlated Electron Systems

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    The effects associated with exciton Bose condensate formation in strongly correlated spin crossover systems are considered within the effective Hamiltonian obtained from the two-orbital Hubbard-Kanamori model. The collective excitations spectrum at various points of the temperature-crystal field phase diagram is calculated. The role of the electron-phonon interaction is discussed. The exciton and magnetic order photoenhancement (induction) in strongly correlated spin crossover systems a new mechanism based on the cooperative effect of electron-phonon and interatomic exchange interactions and the appearance of a massive collective phase mode is demonstrated

    Interlayer tunneling spectroscopy of graphite at high magnetic field oriented parallel to the layers

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    Interlayer tunneling in graphite mesa-type structures is studied at a strong in-plane magnetic field HH up to 55 T and low temperature T=1.4T=1.4 K. The tunneling spectrum dI/dVdI/dV vs. VV has a pronounced peak at a finite voltage V0V_0. The peak position V0V_0 increases linearly with HH. To explain the experiment, we develop a theoretical model of graphite in the crossed electric EE and magnetic HH fields. When the fields satisfy the resonant condition E=vHE=vH, where vv is the velocity of the two-dimensional Dirac electrons in graphene, the wave functions delocalize and give rise to the peak in the tunneling spectrum observed in the experiment.Comment: 6 pages, 6 figures; corresponds to the published version in Eur. Phys. J. Special Topics, Proceedings of the IMPACT conference 2012, http://lptms.u-psud.fr/impact2012

    Influence of the temperature factor on the hydraulic resistance of pressure pipes

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    The assessment of the temperature factor influence on the pressure pipeline hydraulic operation mode is very relevant, since it is considered primarily as an opportunity to reduce the cost of mechanical water transportation. Smaller pressure pipe hydraulic resistances save the electrical energy consumption, and the temperature factor has an additional positive effect on the energy saving process. The purpose of the research is to identify the nature of changes in the hydraulic friction value in relation to the temperature conditions of the transferred water temperature and environmental conditions in the designed ranges, with the subsequent possible control of the transportation process with minimum electrical energy consumption. The method of achieving these goals is an experimental and analytical approach aimed at determining the dynamics of changes in the hydraulic parameters of pipelines made of various materials. The tasks of experimental bench studies include the development of a method for calculating the values of hydraulic friction coefficients for pressure pipelines. The results of hydraulic experiments and comprehensive analysis of the experimental and calculated data for determining the hydraulic friction coefficients for polyethylene pipe are presented. The calculated values of the hydraulic friction coefficient were compared with the experimental ones, which enabled identification of their sufficiently high convergence. The conclusions show a positive effect of reducing hydraulic resistances depending on the increase in the temperature of the transported water

    Structure of 2-Methyl-5,6,7-triphenyl-6,7-dihydropyrazolo[2,3-\u3cem\u3ea\u3c/em\u3e]pyrimidine

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    C25H21N3, Mr = 363.46, monoclinic, P21/n, a = 9.245 (2), b = 23.502 (5), c = 9.340 (2) Å, β= 103.50(3)°, V=1973.3(2) Å3, Z=4, Dx= 1.220 (2) g cm-3, λ (Mo Kα )= 0.71069 Å, μ = 0.068 cm-1, F(000) = 768, T= 292 K, R = 0.091 for 1442 unique observed reflections. The dihydropyrimidine ring adopts a distorted sofa conformation. The aryl substituents on the saturated C atoms have an axial orientation

    DIGITAL TOOLS IN THE DESIGN PRACTICE FOR RECONSTRUCTION OF UNDERGROUND PIPELINES WITH TRENCHLESS METHODS

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    The article focuses on the possibilities of multi-optional design of repair and rehabilitation works on dilapidated pressure pipeline networks with the use of automated complexes in order to achieve minimum energy costs in water transportation with regard to the temperature factor. Two automated programs based on hydraulic and energy calculation operations are presented as digital tools. As a basic variant of reconstruction of dilapidated pipelines, the trenchless Swagelining technology was accepted. It is realized by pulling pre-compressed polymer pipes into old pipelines with their subsequent straightening. The paper presents information on regulatory and technical documentation and the application of advanced technology, installation and operation conditions, as well as comparative assessment of energy consumption after reconstruction of dilapidated sections of pipelines with polymer pipes with the possibility of minimizing energy consumption during water transportation under non-isothermal conditions of pipeline operation

    Geometric Phantom Categories

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    In this paper we give a construction of phantom categories, i.e. admissible triangulated subcategories in bounded derived categories of coherent sheaves on smooth projective varieties that have trivial Hochschild homology and trivial Grothendieck group. We also prove that these phantom categories are phantoms in a stronger sense, namely, they have trivial K-motives and, hence, all their higher K-groups are trivial too.Comment: LaTeX, 18 page

    Genomic signatures of freshwater adaptation in Pacific herring (Clupea pallasii)

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    Pacific herring (Clupea pallasii) is an essential target of commercial fishing in the North Pacific Ocean. Previous studies have suggested the existence of marine and lake ecological forms of this species within its range. The lake ecological form of herring has a shortened life cycle, spending the winter and spawning in brackish waters near the shoreline without long migrations for feed-ing; it also has a relatively smaller body size than the marine form. Genetic-based studies have shown that brackish water Pacific herring not only can be distinguished as a separate lake eco-logical form but possibly has its genetic legacy. Here, as part of an ongoing study, using ddRAD-sequencing data for marine and lake ecological forms from a total of 54 individuals and methods of comparative bioinformatics, we describe genomic signatures of freshwater adaptivity in Pacific herring. In total, 253 genes containing discriminating SNPs were found, and part of those genes was organized into genome clusters, also known as “genomic islands of divergence”. Moreover, the Tajima’s D test showed that these loci are under directional selection in the lake populations of the Pacific herring. Yet, most discriminating loci between the lake and marine eco-logical forms of Pacific herring do not intersect (by gene name) with those in other known marine fish species with known freshwater/brackish populations. However, some are associated with the same physiological trait—osmoregulation.publishedVersio
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