53 research outputs found

    Repulsive Casimir interaction: Boyer oscillators at nanoscale

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    We study the effect of temperature on the repulsive Casimir interaction between an ideally permeable and an ideally polarizable plate {\it in vacuo}. At small separations or for low temperatures the quantum fluctuations of the electromagnetic field give the main contribution to the interaction, while at large separations or for high temperatures the interaction is dominated by the classical thermal fluctuations of the field. At intermediate separations or finite temperatures both the quantum and thermal fluctuations contribute. For a system composed of one infinitely permeable plate between two ideal conductors at a finite temperature, we identify a {\it stable mechanical equilibrium} state, if the infinitely permeable plate is located in the middle of the cavity. For small displacements the restoring force of this {\it Boyer oscillator} is linear in the deviation from the equilibrium position, with a spring constant that depends inversely on the separation between the two conducting plates and linearly on temperature. Furthermore, an array of such oscillators presents an ideal Einsteinian crystal that displays a fluctuation force between its outer boundaries stemming from the displacement fluctuations of the Boyer oscillators.Comment: 6 pages, 5 figure

    Theory of pore-driven and end-pulled polymer translocation dynamics through a nanopore: An overview

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    We review recent progress on the theory of dynamics of polymer translocation through a nanopore based on the iso-flux tension propagation (IFTP) theory. We investigate both pore-driven translocation of flexible and a semi-flexible polymers, and the end-pulled case of flexible chains by means of the IFTP theory and extensive molecular dynamics (MD) simulations. The validity of the IFTP theory can be quantified by the waiting time distributions of the monomers which reveal the details of the dynamics of the translocation process. The IFTP theory allows a parameter-free description of the translocation process and can be used to derive exact analytic scaling forms in the appropriate limits, including the influence due to the pore friction that appears as a finite-size correction to asymptotic scaling. We show that in the case of pore-driven semi-flexible and end-pulled polymer chains the IFTP theory must be augmented with an explicit {\it trans} side friction term for a quantitative description of the translocation process

    Dynamics of end-pulled polymer translocation through a nanopore

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    We consider the translocation dynamics of a polymer chain forced through a nanopore by an external force on its head monomer on the trans side. For a proper theoretical treatment we generalize the iso-flux tension propagation (IFTP) theory to include friction arising from the trans side subchain. The theory reveals a complicated scenario of multiple scaling regimes depending on the configurations of the cis and the trans side subchains. In the limit of high driving forces ff such that the trans subchain is strongly stretched, the theory is in excellent agreement with molecular dynamics simulations and allows an exact analytic solution for the scaling of the translocation time τ{\tau} as a function of the chain length N0N_0 and ff. In this regime the asymptotic scaling exponents for τN0αfβ{\tau} \sim N_0^{\alpha} f^{\beta} are α=2\alpha=2, and β=1\beta =-1. The theory reveals significant correction-to-scaling terms arising from the cis side subchain and pore friction, which lead to a very slow approach to α=2\alpha =2 from below as a function of increasing N0N_0.Comment: 5 pages, 4 figure

    ON THE IMPORTANCE OF DATA QUALITY IN INFORMATION SYSTEMS RESEARCH AND PH.D. CURRICULA

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    Data quality procedures are vital in conducting survey research, yet they are under-emphasized in information systems (IS) Ph.D. curricula and published journal articles. In this research-in-progress, we offer the “5-C Framework” to evaluate the current state of IS survey research, as it pertains to data quality, provide insight into where IS Ph.D. curricula may be lacking, and offer a basis for developing new curricula that address those gaps. In pursuit of our objectives, we present preliminary findings from our analysis of IS survey research between 2008 and 2017. This work should interest those developing IS Ph.D. curricula. Establishing guidelines, based on the 5-C framework, can aid educators in teaching Ph.D. students how to enact and communicate data quality procedures effectively
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