5,773 research outputs found

    Glueball Masses from Hamiltonian Lattice QCD

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    We calculate the masses of the 0++0^{++}, 00^{--} and 1+1^{+-} glueballs from QCD in 3+1 dimensions using an eigenvalue equation method for Hamiltonian lattice QCD developed and described elsewhere by the authors. The mass ratios become approximately constants in the coupling region 6/g2[6.0,6.4]6/g^2 \in [6.0,6.4], from which we estimate M(0)/M(0++)=2.44±0.05±0.20M(0^{--})/M(0^{++})=2.44 \pm 0.05 \pm 0.20 and M(1+)/M(0++)=1.91±0.05±0.12M(1^{+-})/M(0^{++})=1.91 \pm 0.05 \pm 0.12.Comment: 12 pages, Latex, figures to be sent upon reques

    A method based on multiscale base-scale entropy and random forests for roller bearings faults diagnosis

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    A method based on multiscale base-scale entropy (MBSE) and random forests (RF) for roller bearings faults diagnosis is presented in this study. Firstly, the roller bearings vibration signals were decomposed into base-scale entropy (BSE), sample entropy (SE) and permutation entropy (PE) values by using MBSE, multiscale sample entropy (MSE) and multiscale permutation entropy (MPE) under different scales. Then the computation time of the MBSE/MSE/MPE methods were compared. Secondly, the entropy values of BSE, SE, and PE under different scales were regarded as the input of RF and SVM optimized by particle swarm ion (PSO) and genetic algorithm (GA) algorithms for fulfilling the fault identification, and the classification accuracy was utilized to verify the effect of the MBSE/MSE/MPE methods by using RF/PSO/GA-SVM models. Finally, the experiment result shows that the computational efficiency and classification accuracy of MBSE method are superior to MSE and MPE with RF and SVM

    Seasonal Characteristics of Black Carbon Aerosol and its Potential Source Regions in Baoji, China

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    Continuous measurements of black carbon (BC) aerosol were made at a midsized urban site in Baoji, China, in 2015. The daily average mass concentrations varied from 0.6 to 11.5 mu g m(-3), with an annual mean value of 2.9 +/- 1.7 mu g m(-3). The monthly variation indicated that the largest loading of BC occurred in January and the smallest in June. The mass concentrations exhibited strong seasonality, with the highest occurring in winter and the lowest in summer. The large BC loadings in winter were attributed to the increased use of fuel for domestic heating and to stagnant meteorological conditions, whereas the low levels in summer were related to the increase in precipitation. BC values exhibited similar bimodal diurnal patterns during the four seasons, with peaks occurring in the morning and evening rush hours and an afternoon trough, which was associated with local anthropogenic activities and meteorological conditions. A potential source contribution function model indicated that the effects of regional transport mostly occurred in spring and winter. The most likely regional sources of BC in Baoji were southern Shaanxi province, northwestern Hubei province, and northern Chongqing during spring, whereas the northeastern Sichuan Basin was the most important source region during winter
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