7,993 research outputs found

    Coordination of Cu(II) and Ni(II) in polymers imprinted so as to optimize amine chelate formation

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    Molecular imprinting has become an established technique. However, little was done on direct investigation of the sorbents produced. In the present work, en ESR method was used for the investigation of the complex formation processes within the sorbents imprinted with copper(II) and nickel(II). The sorbents were synthesized from a mixture of linear low molecular weight polyethyleneimine oligomers. The composition, structure and distribution of complexes in the resin phase were investigated. The effects of the synthesis conditions, loading degree and water content were examined. The presence of certain copper complexes was found to be a convenient characteristic of the imprinting efficiency. The optimum synthesis conditions for obtaining sorbents imprinted with copper(II) or nickel(II) were identified. The imprinting results in the improvement of the stability of the complexes and the selectivity and working capacity of the sorbents. The imprinted samples are also characterized by a more even distribution of chelating sites. The synthesis conditions and loading by ions allow for the regulation of the ratio between individual complexes and magnetic associates in the resin phase. This is a critical point on the future use of the metal containing imprinted sorbents as catalysts. (C) 2003 Published by Elsevier Science Ltd

    Low-energy three-body charge transfer reactions with Coulomb interaction in the final state

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    Three-body charge transfer reactions with Coulomb interaction in the final state are considered in the framework of coordinate-space integro-differential Faddeev-Hahn-type equations within two- and six-state close coupling approximations. The method is employed to study direct muon transfer in low-energy collisions of the muonic hydrogen Hμ_\mu by helium (He++^{++}) and lithium (Li+++^{+++}) nuclei. The experimentally observed isotopic dependence is reproduced.Comment: 14 pages REVTeX, accepted for publication in Journal of Physics

    Memory efficient algorithm for solving the inverse gravimetry problem of finding several boundary surfaces in multilayered medium

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    For solving the inverse gravimetry problem of finding several boundary surfaces in a multilayered medium, the parallel algorithm was constructed and implemented for multicore CPU using OpenMP technology. The algorithm is based on the modified nonlinear conjugate gradient method with weighting factors previously proposed by authors. To reduce the memory requirements and computation time, the modification was constructed on the basis of utilizing the Toeplitz-block-Toeplitz structure of the Jacobian matrix of the integral operator. The model problem of reconstructing three surfaces using the quasi-real gravitational data was solved on a large grid. It was shown that the proposed implementation reduces the computation time by 80% in comparison with the earlier algorithm based on calculating the entire matrix. The parallel algorithm shows good scaling of 94% on 8-core processor. © 2019 Author(s).Ministry of Education and Science of the Republic of Kazakhstan: AP 05133873This work was financially supported by the Ministry of Education and Science of the Republic of Kazakhstan (project AP 05133873)

    Application of confidential intervals for verification of reservoir model at interpretation of well test data

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    The information on arguments of an oil reservoir to a well test from the point of view of the Bayesian inference are express through even allocation of odds in room of arguments. In article application of confidential spacing for a quantitative appraisal of the information receive from the analysis of results of well test which one are us for upgrading of allocations of odds are offered. Use of confidential spacing for an appraisal of a correctness of a choice of a laboratory formation are show

    The chemistry of vibrationally excited H2 in the interstellar medium

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    The internal energy available in vibrationally excited H2 molecules can be used to overcome or diminish the activation barrier of various chemical reactions of interest for molecular astrophysics. In this article we investigate in detail the impact on the chemical composition of interstellar clouds of the reactions of vibrationally excited H2 with C+, He+, O, OH, and CN, based on the available chemical kinetics data. It is found that the reaction of H2 (v>0) and C+ has a profound impact on the abundances of some molecules, especially CH+, which is a direct product and is readily formed in astronomical regions with fractional abundances of vibrationally excited H2, relative to ground state H2, in excess of 10^(-6), independently of whether the gas is hot or not. The effects of these reactions on the chemical composition of the diffuse clouds zeta Oph and HD 34078, the dense PDR Orion Bar, the planetary nebula NGC 7027, and the circumstellar disk around the B9 star HD 176386 are investigated through PDR models. We find that formation of CH+ is especially favored in dense and highly FUV illuminated regions such as the Orion Bar and the planetary nebula NGC 7027, where column densities in excess of 10^(13) cm^(-2) are predicted. In diffuse clouds, however, this mechanism is found to be not efficient enough to form CH+ with a column density close to the values derived from astronomical observations.Comment: accepted for publication in the Astrophysical Journal; 9 pages, 7 figure

    Separation of reservoir layers based on neuro-fuzzy systems

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    In the article, the application algorithms of neural network methods for determining the lithological composition of a well bore according to logging data are studied by training based on the analysis of the correspondence of logs to the available expert opinion. Specialized algorithms for processing the results of network operation have been developed to increase the information content of a signal produced by a neural network and to increase the reliability of recognition

    Parallel Direct and Iterative Methods for Solving the Time-Fractional Diffusion Equation on Multicore Processors

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    The work is devoted to developing the parallel algorithms for solving the initial boundary problem for the time-fractional diffusion equation. After applying the finite-difference scheme to approximate the basis equation, the problem is reduced to solving a system of linear algebraic equations for each subsequent time level. The developed parallel algorithms are based on the Thomas algorithm, parallel sweep algorithm, and accelerated over-relaxation method for solving this system. Stability of the approximation scheme is established. The parallel implementations are developed for the multicore CPU using the OpenMP technology. The numerical experiments are performed to compare these methods and to study the performance of parallel implementations. The parallel sweep method shows the lowest computing time. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The first author (M.A.S.) and fourth author (E.N.) were financially supported by the Ministry of Education and Science of the Republic of Kazakhstan (project AP09258836). The second author (E.N.A.) and third author (V.E.M.) received no external funding

    The intellectual information system for management of geological and technical arrangements during oil field exploitation

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    The intellectual information system for management of geological and technical arrangements during oil fields exploitation is developed. Service-oriented architecture of its software is a distinctive feature of the system. The results of the cluster analysis of real field data received by means of this system are shown
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