14,929 research outputs found

    Migration and Labor Mobility in China

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    China has witnessed the largest labor migration since the reform and opening up policies were implemented. According to the most recent statistics, the total number of rural to urban migrant workers reached 136 million. Migrants are defined as persons who have left out of township for more than 6 months. The migration flow has propelled the economic and societal transition in China through labor productivity enhancement and social restructuring. Accordingly, the Chinese government has improved the migration policies with increasing migration flow and the changes of labor market situations. This report is organized as follows. Section one briefly introduces when and how the migration started by reviewing the history, size and trend, impacts of migration in China and the vulnerability of migrants. Section two reviews the main migration policy changes in the past three decades. Section three illuminates the Lewisian turning point that marks economic development and transitioning in China. Section four discusses the relevance of China’s experiences to other developing economies in terms of economic development and migration policy changes.Migration in China, Labor mobility, Impact of crisis

    Controllability Analysis and Degraded Control for a Class of Hexacopters Subject to Rotor Failures

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    This paper considers the controllability analysis and fault tolerant control problem for a class of hexacopters. It is shown that the considered hexacopter is uncontrollable when one rotor fails, even though the hexacopter is over-actuated and its controllability matrix is row full rank. According to this, a fault tolerant control strategy is proposed to control a degraded system, where the yaw states of the considered hexacopter are ignored. Theoretical analysis indicates that the degraded system is controllable if and only if the maximum lift of each rotor is greater than a certain value. The simulation and experiment results on a prototype hexacopter show the feasibility of our controllability analysis and degraded control strategy.Comment: 21 pages, 7 figures, submitted to Journal of Intelligent & Robotic System

    Determination of f0σf_0-\sigma mixing angle through Bs0J/Ψ f0(980)(σ)B_s^0 \to J/\Psi~f_0(980)(\sigma) decays

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    We study Bs0J/ψf0(980)B_s^0 \to J/\psi f_0(980) decays, the quark content of f0(980)f_0(980) and the mixing angle of f0(980)f_0(980) and σ(600)\sigma(600). We calculate not only the factorizable contribution in QCD facorization scheme but also the nonfactorizable hard spectator corrections in QCDF and pQCD approach. We get consistent result with the experimental data of Bs0J/ψf0(980)B_s^0 \to J/\psi f_0(980) and predict the branching ratio of Bs0J/ψσB_s^0 \to J/\psi \sigma. We suggest two ways to determine f0σf_0-\sigma mixing angle θ\theta. Using the experimental measured branching ratio of Bs0J/ψf0(980)B_s^0 \to J/\psi f_0(980) , we can get the f0σf_0-\sigma mixing angle θ\theta with some theoretical uncertainties. We suggest another way to determine f0σf_0-\sigma mixing angle θ\theta using both of experimental measured decay branching ratios Bs0J/ψf0(980)(σ)B_s^0 \to J/\psi f_0(980) (\sigma) to avoid theoretical uncertainties.Comment: arXiv admin note: substantial text overlap with arXiv:0707.263

    Hexaaqua­cadmium(II) 2,2′-(azino­dimethyl­idyne)dibenzene­sulfonate dihydrate

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    In the title compound, [Cd(H2O)6](C14H10O6N2S2)·2H2O, the complete cation and anion are each generated by crystallographic inversion symmetry. In the crystal structure, the components form a three-dimensional network by way of O—H⋯O and O—H⋯N hydrogen bonds
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