680 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

    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

    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

    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

    First Energy and Angle differential Measurements of e^+e^- -pairs emitted by Internal Pair Conversion of excited Heavy Nuclei

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    We present the first energy and angle resolved measurements of e+e- pairs emitted from heavy nuclei (Z>=40) at rest by internal pair conversion (IPC) of transitions with energies of less than 2MeV as well as recent theoretical results using the DWBA method, which takes full account of relativistic effects, magnetic substates and finite size of the nucleus. The 1.76MeV E0 transition in Zr90 (Sr source) and the 1.77MeV M1 transition in Pb207 (Bi source) have been investigated experimentally using the essentially improved set-up at the double-ORANGE beta-spectrometer of GSI. The measurements prove the capability of the setup to cleanly identify the IPC pairs in the presence of five orders of magnitude higher beta- and gamma background from the same source and to yield essentially background-free sum spectra despite the large background. Using the ability of the ORANGE setup to directly determine the opening angle of the e+e- pairs, the angular correlation of the emitted pairs was measured. In the Zr90 case the correlation could be deduced for a wide range of energy differences of the pairs. The Zr90 results are in good agreement with recent theory. The angular correlation deduced for the M1 transition in Pb207 is in strong disagreement with theoretical predictions derived within the Born approximation and shows almost isotropic character. This is again in agreement with the new theoretical results.Comment: LaTeX, 28 pages incl. 10 PS figures; Accepted by Z.Phys.

    ΛN\Lambda N correlations from the stopped K−K^- reaction on 4{}^4He

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    We have investigated correlations of coincident ΛN\Lambda N pairs from the stopped K−K^- reaction on 4{}^4He, and clearly observed Λp\Lambda p and Λn\Lambda n branches of the two-nucleon absorption process in the ΛN\Lambda N invariant mass spectra. In addition, non-mesonic reaction channels, which indicate possible exotic signals for the formation of strange multibaryon states, have been identified.Comment: 5 pages, 3 figures, submitted to Physical Review Letter

    CuCo2_{2}S4_{4} Deposited on TiO2_{2}: Controlling the pH Value Boosts Photocatalytic Hydrogen Evolution

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    Metallic spinel-type CuCo2_{2}S4_{4} nanoparticles were deposited on nanocrystalline TiO2_{2} (P25®), forming heterostructure nanocomposites. The nanocomposites were characterized in detail by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), nitrogen sorption (BET) and UV/Vis spectroscopy. Variation of the CuCo2_{2}S4_{4}:TiO2_{2} ratio to an optimum value generated a catalyst which shows a very high photocatalytic H2_{2} production rate at neutral pH of 32.3 µmol/h (0.72 mLh–1^{–1}), which is much larger than for pure TiO2_{2} (traces of H2_{2}). The catalyst exhibits an extraordinary long-term stability and after 70 h irradiation time about 2 mmol H2_{2} were generated. An increased light absorption and an efficient charge separation for the sample with the optimal CuCo2_{2}S4_{4}:TiO2_{2} ratio is most probably responsible for the high catalytic activity
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