1,222 research outputs found

    Metal containing polymers from cyclic tetrameric phenylphosphonitrilamides Patent

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    Chemical synthesis of thermally stable organometallic polymers with divalent metal ion and tetraphenylphosphonitrilic unit

    Bifurcations in the theory of current transfer to cathodes of dc discharges and observations of transitions between different modes

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    General scenarios of transitions between different spot patterns on electrodes of dc gas discharges and their relation to bifurcations of steady-state solutions are analyzed. In the case of cathodes of arc discharges, it is shown that any transition between different modes of current transfer is related to a bifurcation of steady-state solutions. In particular, transitions between diffuse and spot modes on axially symmetric cathodes, frequently observed in the experiment, represent an indication of the presence of pitchfork or fold bifurcations of steady-state solutions. Experimental observations of transitions on cathodes of dc glow microdischarges are analyzed and those potentially related to bifurcations of steady-state solutions are identified. The relevant bifurcations are investigated numerically and the computed patterns are found to conform to those observed in the course of the corresponding transitions in the experiment

    Synthesis of linear, double chain, ladder polymers from substituted tetraphosphonitriles Quarterly report, Sep. - Nov. 1966

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    Synthesis of linear, double chain ladder polymers from substituted tetraphosphonitrile

    Uniform Stationary-phase Methods For Energy Spectra Resulting From Collisions In A Complex Potential: Penning And Associative Ionization Of He*(2³S)+He*(23S)

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    Heavy-particle collisions involving strong electronic coupling can be conveniently described by using a complex (optical) potential in the entrance channel. Uniform JWKB stationary-phase techniques are used to evaluate T-matrix elements for transitions where an electron is ejected. The semi-analytic expressions for the resulting electron energy spectra are no more difficult to implement than corresponding ones for totally real potentials. Numerical results are reported for Penning and associative ionization from sub thermal He*(23S)+He*(23S) collisions. These are in excellent agreement with fully quantal, complex-potential computations. The stationary-phase expressions for T-matrix elements and differential cross sections are employed to elucidate the rapid and slow rainbow interference oscillations in the spectra, including the significant effects of turning points and the imaginary width of the entrance-channel potential. © 1990 IOP Publishing Ltd

    Impact stresses and deformations in spherical shells Final report

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    Spherical shell dynamic response on colliding with special elastic impact surface with stress wave analysi

    Modelling cathode spots in glow discharges in the cathode boundary layer geometry

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    Self-organized patterns of cathode spots in glow discharges are computed in the cathode boundary layer geometry, which is the one employed in most of the experiments reported in the literature. The model comprises conservation and transport equations of electrons and a single ion species, written in the drift-diffusion and local-field approximations, and Poisson’s equation. Multiple solutions existing for the same value of the discharge current and describing modes with different configurations of cathode spots are computed by means of a stationary solver. The computed solutions are compared to their counterparts for plane-parallel electrodes, and experiments. All of the computed spot patterns have been observed in the experiment.info:eu-repo/semantics/publishedVersio

    Modelling excited species and their role on kinetic pathways in the non-oxidative coupling of methane by dielectric barrier discharge

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    Acknowledgments We acknowledge and greatly appreciate the assistance from Dr. Mihailova from Plasma Matters B.V. in working with the software Plasimo and from Dr Marcus Campbell Bannerman from the University of Aberdeen for providing access to the computational cluster used for carrying out the simulations in this work. The work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) New Investigator Award, grant no. EP/R031800/1.Peer reviewedPostprin
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