49,984 research outputs found

    Why has China grown so fast? The role of physical and human capital formation

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    Cross-province growth regressions for China are estimated for the reform period. Two research questions are asked. Can the regressions help us to understand why China as a whole has grown so fast? What types of investment matter for China's growth? We address the problem of model uncertainty by adopting two approaches to model selection to consider a wide range of candidate predictors of growth. Starting from the baseline equation, the growth impact of physical and human capital is examined using panel data techniques. Both forms of capital promote economic growth. ‘Investment in innovation’ and private investment are found to be particularly important. Secondary school enrolment contributes to growth, and higher education enrolment even more so

    Weight function for the quantum affine algebra Uq(sl^3)U_q(\hat{sl}_3)

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    We give a precise expression for the universal weight function of the quantum affine algebra Uq(sl^3)U_q(\hat{sl}_3). The calculations use the technique of projecting products of Drinfeld currents on the intersections of Borel subalgebras.Comment: 28 page

    Three realizations of quantum affine algebra Uq(A2(2))U_q(A_2^{(2)})

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    In this article we establish explicit isomorphisms between three realizations of quantum twisted affine algebra Uq(A2(2))U_q(A_2^{(2)}): the Drinfeld ("current") realization, the Chevalley realization and the so-called RLLRLL realization, investigated by Faddeev, Reshetikhin and Takhtajan.Comment: 15 page

    A re-visit of the phase-resolved X-ray and \gamma-ray spectra of the Crab pulsar

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    We use a modified outer gap model to study the multi-frequency phase-resolved spectra of the Crab pulsar. The emissions from both poles contribute to the light curve and the phase-resolved spectra. Using the synchrotron self-Compton mechanism and by considering the incomplete conversion of curvature photons into secondary pairs, the observed phase-averaged spectrum from 100 eV - 10 GeV can be explained very well. The predicted phase-resolved spectra can match the observed data reasonably well, too. We find that the emission from the north pole mainly contributes to Leading Wing 1. The emissions in the remaining phases are mainly dominated by the south pole. The widening of the azimuthal extension of the outer gap explains Trailing Wing 2. The complicated phase-resolved spectra for the phases between the two peaks, namely Trailing Wing 1, Bridge and Leading Wing 2, strongly suggest that there are at least two well-separated emission regions with multiple emission mechanisms, i.e. synchrotron radiation, inverse Compton scattering and curvature radiation. Our best fit results indicate that there may exist some asymmetry between the south and the north poles. Our model predictions can be examined by GLAST.Comment: 35 pages, 13 figures, accepted to publish in Ap

    Internal stress wave measurements in solids subjected to lithotripter pulses

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    Semiconductor strain gauges were used to measure the internal strain along the axes of spherical and disk plaster specimens when subjected to lithotripter shock pulses. The pulses were produced by one of two lithotripters. The first source generates spherically diverging shock waves of peak pressure approximately 1 MPa at the surface of the specimen. For this source, the incident and first reflected pressure (P) waves in both sphere and disk specimens were identified. In addition, waves reflected by the disk circumference were found to contribute significantly to the strain fields along the disk axis. Experimental results compared favorably to a ray theory analysis of a spherically diverging shock wave striking either concretion. For the sphere, pressure contours for the incident P wave and caustic lines were determined theoretically for an incident spherical shock wave. These caustic lines indicate the location of the highest stresses within the sphere and therefore the areas where damage may occur. Results were also presented for a second source that uses an ellipsoidal reflector to generate a 30-MPa focused shock wave, more closely approximating the wave fields of a clinical extracorporeal lithotripter

    Molecular Dynamics Study of Bamboo-like Carbon Nanotube Nucleation

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    MD simulations based on an empirical potential energy surface were used to study the nucleation of bamboo-like carbon nanotubes (BCNTs). The simulations reveal that inner walls of the bamboo structure start to nucleate at the junction between the outer nanotube wall and the catalyst particle. In agreement with experimental results, the simulations show that BCNTs nucleate at higher dissolved carbon concentrations (i.e., feedstock pressures) than those where non-bamboolike carbon nanotubes are nucleated
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