704,927 research outputs found

    The finite-temperature thermodynamics of a trapped unitary Fermi gas within fractional exclusion statistics

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    We utilize a fractional exclusion statistics of Haldane and Wu hypothesis to study the thermodynamics of a unitary Fermi gas trapped in a harmonic oscillator potential at ultra-low finite temperature. The entropy per particle as a function of the energy per particle and energy per particle versus rescaled temperature are numerically compared with the experimental data. The study shows that, except the chemical potential behavior, there exists a reasonable consistency between the experimental measurement and theoretical attempt for the entropy and energy per particle. In the fractional exclusion statistics formalism, the behavior of the isochore heat capacity for a trapped unitary Fermi gas is also analyzed.Comment: 6 pages, 6 figure

    Macroscale boundary conditions for a non-linear heat exchanger

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    Multiscale modelling methodologies build macroscale models of materials with complicated fine microscale structure. We propose a methodology to derive boundary conditions for the macroscale model of a prototypical non-linear heat exchanger. The derived macroscale boundary conditions improve the accuracy of macroscale model. We verify the new boundary conditions by numerical methods. The techniques developed here can be adapted to a wide range of multiscale reaction-diffusion-advection systems

    High-order harmonic generation from diatomic molecules with large internuclear distance: The effect of two-center interference

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    In the present paper, we investigate the high-order harmonic generation (HHG) from diatomic molecules with large internuclear distance using a strong field approximation (SFA) model. We find that the hump and dip structure emerges in the plateau region of the harmonic spectrum, and the location of this striking structure is sensitive to the laser intensity. Our model analysis reveals that two-center interference as well as the interference between different recombination electron trajectories are responsible for the unusual enhanced or suppressed harmonic yield at a certain order, and these interference effects are greatly influenced by the laser parameters such as intensity.Comment: 5 pages,4 figure

    Design and assessment of a multiple sensor fault tolerant robust control system

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    This paper presents an enhanced robust control design structure to realise fault tolerance towards sensor faults suitable for multi-input-multi-output (MIMO) systems implementation. The proposed design permits fault detection and controller elements to be designed with considerations to stability and robustness towards uncertainties besides multiple faults environment on a common mathematical platform. This framework can also cater to systems requiring fast responses. A design example is illustrated with a fast, multivariable and unstable system, that is, the double inverted pendulum system. Results indicate the potential of this design framework to handle fast systems with multiple sensor faults

    First-principles investigation of transient current of molecular devices by using complex absorbing potential

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    Based on the non-equilibrium Green's function (NEGF) coupled with density function theory (DFT), namely, NEGF-DFT quantum transport theory, we propose an efficient formalism to calculate the transient current of molecular devices under a step-like pulse from first principles. By combining NEGF-DFT with the complex absorbing potential (CAP), the computational complexity of our formalism (NEGF-DFT-CAP) is proportional to \emph{O}(N) where NN is the number of time steps in the time-dependent transient calculation. Compared with state-of-the-art algorithm of first principles time-dependent calculation that scales with at least N2N^2, this order N technique drastically reduces the computational burden making it possible to tackle realistic molecular devices. To ensure the accuracy of our method, we carry out the benchmark calculation compared with exact NEGF-TDDFT formalism and they agree well with each other. As an illustration, we investigate the transient current of molecular device Al-C3_3-Al from first principles

    Rethinking bank business models: the role of intangibles

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    <p>Purpose: This paper provides a new way of rethinking banking models by using qualitative research on intangibles. This is required because the banking sector has been transformed significantly by the changing environment over the past two decades. The 2007-2009 financial crisis also added to concerns about existing bank business models.</p> <p>Design/Methodology approach: Using qualitative data collected from interviews with bank managers and analysts in the UK, this paper develops a grounded theory of bank intangibles.</p> <p>Findings: The model reveals how intangibles and tangible/financial resources interact in the bank value creation process, how they actively respond to environmental changes, how bank intangibles are understood by external observers such as analysts, and how bankers and analysts differ in their views.</p> <p>Research implications: Grounded theory provides the means to further develop bank models as business models and theoretical models. This provides the means to think beyond conventional finance constructs and to relate bank models to a wider theoretical literature concerning intellectual capital, organisational and social systems theory, and ‘performativity’.</p> <p>Practical implications: Such development of bank models and of a systems perspective is critical to the understanding of banks by bankers, by observers and for their ‘critical and reflexive performativity’. It also has implications for systemic risk and bank regulation.</p> <p>Social implications: Improvement in bank models and their use in open and transparent processes are key means to improve public accountability of banks.</p> <p>Originality: The paper reveals the core role of intellectual capital (IC) in banks, in markets, and in developing theory and research at firm and system levels. </p&gt
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