135 research outputs found

    Unusual, basin-scale, fluid–rock interaction in the Palaeoproterozoic Onega basin from Fennoscandia : Preservation in calcite ή18O of an ancient high geothermal gradient

    Get PDF
    Acknowledgements We acknowledge financial support from ICDP for the drilling programme. AEF, ATB and ARP thank NERC for financial support through NE/G00398X/1. VAM thanks the Norwegian Research Council for financial support through 191530/V30. We are grateful for sample preparation and analyses to all the personnel at NGU lab. At SUERC we enjoyed exceptional analytical support from Julie Dougans. Anonymous reviewers and the editor provided comments that improved the final manuscript.Peer reviewedPostprin

    Differential cross sections for muonic atom scattering from hydrogenic molecules

    Get PDF
    The differential cross sections for low-energy muonic hydrogen atom scattering from hydrogenic molecules are directly expressed by the corresponding amplitudes for muonic atom scattering from hydrogen-isotope nuclei. The energy and angular dependence of these three-body amplitudes is thus taken naturally into account in scattering from molecules, without involving any pseudopotentials. Effects of the internal motion of nuclei inside the target molecules are included for every initial rotational-vibrational state. These effects are very significant as the considered three-body amplitudes often vary strongly within the energy interval â‰Č0.1\lesssim{}0.1 eV. The differential cross sections, calculated using the presented method, have been successfully used for planning and interpreting many experiments in low-energy muon physics. Studies of Ό−\mu^{-} nuclear capture in pÎŒp\mu and the measurement of the Lamb shift in pÎŒp\mu atoms created in H2_2 gaseous targets are recent examples.Comment: 21 pages, 13 figures, submitted to Phys. Rev.

    Petrography and geochemistry of carbonate rocks of the Paleoproterozoic Zaonega Formation, Russia : Documentation of C-13-depleted non-primary calcite

    Get PDF
    The Norwegian Research Council grant 191530/V30 to V.A. Melezhik fully funded the work of AEC, VAM and AL. ATB was supported by NERC grant NE/G00398X/1 to AEF and ARP. We are grateful for sample preparation and analyses to all the personnel at NGU lab. We appreciate the work on carbon and oxygen isotope analyses by Julie Dougans and Chris Taylor. Bojan Otoničar organized and helped with the CL work at the Karst Research Institute at Postojna. Arrangement of TOC, IC, and TC analyses at University of MĂŒnster is acknowledged to Harald Strauss.Peer reviewedPostprin

    Travertine precipitation in the Paleoproterozoic KuetsjÀrvi Sedimentary Formation, Pechenga Greenstone Belt, NE Fennoscandian Shield

    Get PDF
    PES was supported by VÀisÀlÀ Foundation (Finnish Academy of Science and Letters) and the Finnish Doctoral Program in Geology. ATB was supported by NERC grant NE/G00398X/1. VAM was supported by NFR grant 191530/V30 (projects 331000 and 802795). This is a contribution (paper) # 18 to the ICDP FAR-DEEP project.Peer reviewedPublisher PD

    Multi-Channel Atomic Scattering and Confinement-Induced Resonances in Waveguides

    Full text link
    We develop a grid method for multi-channel scattering of atoms in a waveguide with harmonic confinement. This approach is employed to extensively analyze the transverse excitations and deexcitations as well as resonant scattering processes. Collisions of identical bosonic and fermionic as well as distinguishable atoms in harmonic traps with a single frequency ω\omega permitting the center-of-mass (c.m.) separation are explored in depth. In the zero-energy limit and single mode regime we reproduce the well-known confinement-induced resonances (CIRs) for bosonic, fermionic and heteronuclear collisions. In case of the multi-mode regime up to four open transverse channels are considered. Previously obtained analytical results are extended significantly here. Series of Feshbach resonances in the transmission behaviour are identified and analyzed. The behaviour of the transmission with varying energy and scattering lengths is discussed in detail. The dual CIR leading to a complete quantum suppression of atomic scattering is revealed in multi-channel scattering processes. Possible applications include, e.g., cold and ultracold atom-atom collisions in atomic waveguides and electron-impurity scattering in quantum wires.Comment: 35 pages, 18 figure

    Fabrication and Characterization of Anionic Exchange Membranes Based on Chitosan/Poly (Vinyl) Alcohol and Chitosan/Chondroitin Doped with an Amino Cumulene Derivative and Carbon Nanotubes

    Get PDF
    Anionic exchange membranes mainly based on mixed matrix membranes (MMM) via the crosslinking of either chitosan (CHT) with poly (vinyl alcohol) (CHT : PVA) or CHT with chondroitin sulfate (CHT : CS) in a 50 : 50 wt% were synthesized. The doping of CHT, CHT : PVA and CHT : CS membranes with either the dispersant agent aminocumulene derivative (named AC, coming from the polycondensation of hexamethylenetetramine in an anhydrous acid medium) or with the carbonaceous inch made of multi-walled carbon nanotubes (CNT) dispersed by using AC to perform (AC/CNT) were characterized by the exploration of the topology by scanning electron microscopy, the determination of water uptake, and the analysis of X-ray diffraction spectroscopy together with the measurement of the anionic conductivity by using electrochemical impedance spectroscopy. Results revealed that the modification of the MMMs with the above inorganic carbonaceous fillers, i.e. AC or AC/CNT, improved remarkably the OH– conductivity for all membranes. The modified CHT:CS blend membranes exhibited the highest ionic conductivities of the series. Water uptake increased for the modified CHT and CHT : PVA membranes, whereas a remarkable reduction of water uptake for the CHT : CS based membranes took place. The best membranes in terms of anionic conductivity were correlated with crystallinity and water uptake.The research was carried out at the expense of a grant from the Russian Science Foundation (project No. 15-13-10038). AG acknowledges the Presidential fellowship programme of the Ministry of Education and Science of the Russian Federation. Also LGC and JI are grateful to the Spanish MINECO through the project CTQ2016-76231-C2-2-R

    Wave packet evolution approach to ionization of hydrogen molecular ion by fast electrons

    Get PDF
    The multiply differential cross section of the ionization of hydrogen molecular ion by fast electron impact is calculated by a direct approach, which involves the reduction of the initial 6D Schr\"{o}dinger equation to a 3D evolution problem followed by the modeling of the wave packet dynamics. This approach avoids the use of stationary Coulomb two-centre functions of the continuous spectrum of the ejected electron which demands cumbersome calculations. The results obtained, after verification of the procedure in the case atomic hydrogen, reveal interesting mechanisms in the case of small scattering angles.Comment: 7 pages, 8 Postscript figure

    The District Heating in the Context of the Active Consumers Development in Smart Energy Systems

    Get PDF
    The paper defines the main factors of the smart energy systems that influence on the district heating. Noted increase in the regulatory impact of electric energy system on the district heating and increase in roles of the distribution and consumption of thermal energy. Urban population and other consumers of energy become equal partners of the utilities and acquire the status of "active" consumers. The heating supply companies need to develop a new model of management of heating regimes with dynamic synchronization with energy system and "active" consumers. One of the most important conditions of the achievement of the cost reduction, reliability and quality increase in community facilities is active consumer's behavior

    Hydrogen and Helium Atoms and Molecules in an Intense Magnetic Field

    Get PDF
    We calculate the atomic structure of hydrogen and helium, atoms and molecules in an intense magnetic field, analytically and numerically with a judiciously chosen basis.Comment: 16 pages, 5 figures, to appear in Phys. Rev.
    • 

    corecore