Data Mining - Concepts and Techniques.

We calculate the double resonant (DR) Raman spectrum of graphene, and determine the lines associated to both phonon-defect processes, and two-phonons ones. Phonon and electronic dispersions reproduce calculations based on density functional theory corrected with GW. Electron-light, -phonon, and -defect scattering matrix elements and the electronic linewidth are explicitly calculated. Defect-induced processes are simulated by considering different kind of idealized defects. For an excitation energy of $\epsilon_L=2.4$ eV, the agreement with measurements is very good and calculations reproduce: the relative intensities among phonon-defect or among two-phonon lines; the measured small widths of the D, $D'$, 2D and $2D'$ lines; the line shapes; the presence of small intensity lines in the 1800, 2000 cm$^{-1}$ range. We determine how the spectra depend on the excitation energy, on the light polarization, on the electronic linewidth, on the kind of defects and on their concentration. According to the present findings, the intensity ratio between the $2D'$ and 2D lines can be used to determine experimentally the electronic linewidth. The intensity ratio between the $D$ and $D'$ lines depends on the kind of model defect, suggesting that this ratio could possibly be used to identify the kind of defects present in actual samples. Charged impurities outside the graphene plane provide an almost undetectable contribution to the Raman signal.

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Theory of double-resonant Raman spectra in graphene: intensity and line shape of defect-induced and two-phonon bands

Mechanical model development of rolling bearing-rotor systems: A review

A rolling bearing is an essential component of a rotating mechanical transmission system Its performance and quality directly affects the life and reliability of machinery Bearings’ performance and reliability need high requirements because of a more complex and poor working conditions of bearings A bearing with high reliability reduces equipment operation accidents and equipment maintenance costs and achieves condition-based maintenance First in this paper, the development of technology of the main individual physical condition monitoring and fault diagnosis of rolling bearings are introduced, then the fault diagnosis technology of multi-sensors information fusion is introduced, and finally, the advantages, disadvantages, and trends developed in the future of the detection main individual physics technology and multi-sensors information fusion technology are summarized This paper is expected to provide the necessary basis for the follow-up study of the fault diagnosis of rolling bearings and a foundational knowledge for researchers about rolling bearings

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Ke Yan

Papers

Investigation on heat dissipation characteristic of ball bearing cage and inside cavity at ultra high rotation speed

Thermal-deformation coupling in thermal network for transient analysis of spindle-bearing system

Theoretical and experimental investigation on the thermal characteristics of double-row tapered roller bearings of high speed locomotive

A novel MP-LSTM method for ship trajectory prediction based on AIS data

A comprehensive study on the speed-varying stiffness of ball bearing under different load conditions