797 research outputs found

    Refactoring Legacy JavaScript Code to Use Classes: The Good, The Bad and The Ugly

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    JavaScript systems are becoming increasingly complex and large. To tackle the challenges involved in implementing these systems, the language is evolving to include several constructions for programming- in-the-large. For example, although the language is prototype-based, the latest JavaScript standard, named ECMAScript 6 (ES6), provides native support for implementing classes. Even though most modern web browsers support ES6, only a very few applications use the class syntax. In this paper, we analyze the process of migrating structures that emulate classes in legacy JavaScript code to adopt the new syntax for classes introduced by ES6. We apply a set of migration rules on eight legacy JavaScript systems. In our study, we document: (a) cases that are straightforward to migrate (the good parts); (b) cases that require manual and ad-hoc migration (the bad parts); and (c) cases that cannot be migrated due to limitations and restrictions of ES6 (the ugly parts). Six out of eight systems (75%) contain instances of bad and/or ugly cases. We also collect the perceptions of JavaScript developers about migrating their code to use the new syntax for classes.Comment: Paper accepted at 16th International Conference on Software Reuse (ICSR), 2017; 16 page

    On the influence of the magnetic field of the GSI experimental storage ring on the time-modulation of the EC-decay rates of the H-like mother ions

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    We investigate the influence of the magnetic field of the Experimental storage ring (ESR) at GSI on the periodic time-dependence of the orbital K-shell electron capture decay (EC(EC) rates of the H--like heavy ions. We approximate the magnetic field of the ESR by a uniform magnetic field. Unlike the assertion by Lambiase et al., arXiv: 0811.2302 [nucl-th], we show that a motion of the H-like heavy ion in a uniform magnetic field cannot be the origin of the periodic time-dependence of the EC-decay rates of the H-like heavy ions.Comment: 3 pages, 1 figur

    Time-Resolved Diffusing Wave Spectroscopy for selected photon paths beyond 300 transport mean free paths

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    This paper is devoted to the theoretical and experimental demonstration of the possibility to perform time-resolved diffusing wave spectroscopy: we successfully registered field fluctuations for selected photon path lengths that can overpass 300 transport mean free paths. Such a performance opens new possibilities for biomedical optics applications.Comment: 12 pages, 3 figure

    An Extended Huckel Theory based Atomistic Model for Graphene Nanoelectronics

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    An atomistic model based on the spin-restricted extended Huckel theory (EHT) is presented for simulating electronic structure and I-V characteristics of graphene devices. The model is applied to zigzag and armchair graphene nano-ribbons (GNR) with and without hydrogen passivation, as well as for bilayer graphene. Further calculations are presented for electric fields in the nano-ribbon width direction and in the bilayer direction to show electronic structure modification. Finally, the EHT Hamiltonian and NEGF (Nonequilibrium Green's function) formalism are used for a paramagnetic zigzag GNR to show 2e2/h quantum conductance.Comment: 5 pages, 8 figure

    Incoherent Transport through Molecules on Silicon in the vicinity of a Dangling Bond

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    We theoretically study the effect of a localized unpaired dangling bond (DB) on occupied molecular orbital conduction through a styrene molecule bonded to a n++ H:Si(001)-(2x1) surface. For molecules relatively far from the DB, we find good agreement with the reported experiment using a model that accounts for the electrostatic contribution of the DB, provided we include some dephasing due to low lying phonon modes. However, for molecules within 10 angstrom to the DB, we have to include electronic contribution as well along with higher dephasing to explain the transport features.Comment: 9 pages, 5 figure

    Precision spectroscopy of pionic 1s states of Sn nuclei and evidence for partial restoration of chiral symmetry in the nuclear medium

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    Deeply bound 1s states of π\pi^- in 115,119,123^{115,119,123}Sn were preferentially observed using the Sn(dd,3^3He) pion-transfer reaction under the recoil-free condition. The 1s binding energies and widths were precisely determined, and were used to deduce the isovector parameter of the s-wave pion-nucleus potential to be b1=0.115±0.007 mπ1b_1 =-0.115\pm 0.007 ~m_{\pi}^{-1}. The observed enhancement of b1|b_1| over the free πN\pi N value (b1free/b1=0.78±0.05b_1^{\rm free}/b_1 = 0.78 \pm 0.05) indicates a reduction of the chiral order parameter, fπ(ρ)2/fπ20.64f^{*}_{\pi} (\rho)^2/f_{\pi}^2 \approx 0.64, at the normal nuclear density, ρ=ρ0\rho = \rho_0.Comment: 4 pages including 3 postscript figures, RevTeX 4 with multirow.sty, submitted to Physical Review Letter

    Extended Huckel theory for bandstructure, chemistry, and transport. II. Silicon

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    In this second paper, we develop transferable semi-empirical parameters for the technologically important material, silicon, using Extended Huckel Theory (EHT) to calculate its electronic structure. The EHT-parameters areoptimized to experimental target values of the band dispersion of bulk-silicon. We obtain a very good quantitative match to the bandstructure characteristics such as bandedges and effective masses, which are competitive with the values obtained within an sp3d5ssp^3 d^5 s^* orthogonal-tight binding model for silicon. The transferability of the parameters is investigated applying them to different physical and chemical environments by calculating the bandstructure of two reconstructed surfaces with different orientations: Si(100) (2x1) and Si(111) (2x1). The reproduced π\pi- and π\pi^*-surface bands agree in part quantitatively with DFT-GW calculations and PES/IPES experiments demonstrating their robustness to environmental changes. We further apply the silicon parameters to describe the 1D band dispersion of a unrelaxed rectangular silicon nanowire (SiNW) and demonstrate the EHT-approach of surface passivation using hydrogen. Our EHT-parameters thus provide a quantitative model of bulk-silicon and silicon-based materials such as contacts and surfaces, which are essential ingredients towards a quantitative quantum transport simulation through silicon-based heterostructures.Comment: 9 pages, 9 figure
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