389 research outputs found

    A comparative study on the strengths and weaknesses of the students between China and Hong Kong

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    In August 1999, three lecturers and fourteen students of Zhejiang University of Technology (ZUT) and Hangzhou Institute Applied Engineering (HIAE) were invited by the Department of Electrical & Communications Engineering (EE) of Institute of Vocational & Education Tsing Yi (IVE/TY) coming to Hong Kong for a Student Exchange Summer Camp. Joining the camp were seven year 1 Higher Diploma students from the EE department. The objectives of the camp were three folds: (a) to find out any difference in the command of English for the post secondary school students from China and Hong Kong; (b) to substantiate an effective means for the learning of Putonghu ; and (c) to investigate the practical skills and mentality of these students. A series of activitie s were organized for the students and their performances in all activities were analyzed to achieve the objectives of the comparative study for these two groups of students

    A framework for optimizing the cost and performance of next-generation IP routers

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    First- and second-order phase transitions in a driven lattice gas with nearest-neighbor exclusion

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    A lattice gas with infinite repulsion between particles separated by ≀1\leq 1 lattice spacing, and nearest-neighbor hopping dynamics, is subject to a drive favoring movement along one axis of the square lattice. The equilibrium (zero drive) transition to a phase with sublattice ordering, known to be continuous, shifts to lower density, and becomes discontinuous for large bias. In the ordered nonequilibrium steady state, both the particle and order-parameter densities are nonuniform, with a large fraction of the particles occupying a jammed strip oriented along the drive. The relaxation exhibits features reminiscent of models of granular and glassy materials.Comment: 8 pages, 5 figures; results due to bad random number generator corrected; significantly revised conclusion

    Generation of entangled states of two atoms inside a leaky cavity

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    An in-depth theoretical study is carried out to examine the quasi-deterministic entanglement of two atoms inside a leaky cavity. Two Λ\Lambda-type three-level atoms, initially in their ground states, may become maximally entangled through the interaction with a single photon. By working out an exact analytic solution, we show that the probability of success depends crucially on the spectral function of the injected photon. With a cavity photon, one can generate a maximally entangled state with a certain probability that is always less than 50%. However, for an injected photon with a narrower spectral width, this probability can be significantly increased. In particular, we discover situations in which entanglement can be achieved in a single trial with an almost unit probability

    Computational Design and Optimisation of Pin Fin Heat Sinks with Rectangular Perforations

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    The benefits of using pin heat sinks (PHSs) with single, rectangular slotted or notched pin perforations, are explored computationally, using a conjugate heat transfer model. Results show that the heat transfer increases monotonically while the pressure drop decreases monotonically as the size of the rectangular perforation increases. Performance comparisons with PHSs with multiple circular perforations show favourable heat transfer and pressure drop characteristics. However, the reduced manufacturing complexity of rectangular notched pins in particular provide strong motivation for their use in practical applications. Detailed parameterisation and optimisation studies into the benefits of single rectangular notch perforations demonstrate the scope for improving heat transfer and reducing mechanical fan power consumption yet further by careful design of pin density and pin perforations in PHSs

    First principles study of point defects in titanium oxycarbide

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    We have performed first principles density functional theory calculations to study the formation energy of point defects in TiC, TiO and TiCO compounds. The formation energy of isolated vacancies were obtained for different equilibrium conditions. For binary compounds, we have also calculated the formation energy of antisite defects. It was found that the defect formation energies strongly depend on the chemical environment. Our results show that C vacancies are easily formed in TiC and TiCO. For the TiO compound, Ti vacancies are highly probable to occur and O vacancies are also easily formed under titanium rich atmosphere.Fundação para a CiĂȘncia e a Tecnologia (FCT) – Programa Operacional “CiĂȘncia , Tecnologia, Inovação” – CONC-REEQ/443/EEI/2005, POCTI/CTM/69362/200

    Evolution of the electronic structure with size in II-VI semiconductor nanocrystals

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    In order to provide a quantitatively accurate description of the band gap variation with sizes in various II-VI semiconductor nanocrystals, we make use of the recently reported tight-binding parametrization of the corresponding bulk systems. Using the same tight-binding scheme and parameters, we calculate the electronic structure of II-VI nanocrystals in real space with sizes ranging between 5 and 80 {\AA} in diameter. A comparison with available experimental results from the literature shows an excellent agreement over the entire range of sizes.Comment: 17 pages, 4 figures, accepted in Phys. Rev.

    Grain Surface Models and Data for Astrochemistry

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    AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∌25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio
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