2,284 research outputs found

    Adaptive Signal Decomposition Methods for Vibration Signals of Rotating Machinery

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    Vibrationā€based condition monitoring and fault diagnosis are becoming more common in the industry to increase machine availability and reliability. Considerable research efforts have recently been directed towards the development of adaptive signal processing methods for fault diagnosis. Two adaptive signal decomposition methods, i.e. the empirical mode decomposition (EMD) and the local mean decomposition (LMD), are widely used. This chapter is intended to summarize the recent developments mostly based on the authorsā€™ works. It aims to provide a valuable reference for readers on the processing and analysis of vibration signals collected from rotating machinery

    Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

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    We develop the method for the calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energy. It is extended for nuclear reactions at low energy and intermediate energy by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with the 30 experimental data within 10 percent accuracy.The comparison between the numerical results and the 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies the quite different mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root mean square radii of these nuclei can be extracted from above comparison based on the improved Glauber model, which indicate clearly the halo structures of these nuclei. Especially, it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections induced by the halo nuclei due to the very weak binding and the very extended density distribution.Comment: 15 pages,2 figures. Communucations in Theoretical Physics, (2003) in pres

    Research on the Innovation of Business Ecosystem Model in Chinaā€™s 0nline Food Reservation Market at Sharing Economic Era

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    At the sharing economy era, the online food reservation market has experienced great changes, such as the mobilization of orderingļ¼Œcooperation of logistics , diversification of revenue stream. The ordering patterns has also changed from network order to improve user experience. At present, online food reservation market has difficulties inquickly dealing with the impacts and challenges bought by external environment due to lack of coordination and sharing mechanisms and competition over cooperation among economic individuals.Based on the theory of business ecosystem, this paper focuses on the impacts and challenges brought by the sharing economic era and takes ā€œHuijiachifanā€ as a case study and proposes new framework of business ecosystem model in China\u27s online food reservation market
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