A method was developed for the determination of major, minor and trace elements in a submarine polymetallic nodule by x-ray fluorescence spectrometry. Fusion of the sample was performed in gfraphite crucibles using a 1 : 3 dilution ratio with an Li,B,O,-Li,CO,-LiNO, flux. Calibration was carried out with synthetic standards. The absorption-enhancement effects for 28 analytes were each corrected using influence coeftjcients generated by the COLA equation. The results obtained were in relatively good agreement with the recommended values for the Chinese reference material GSPN-1. The technique of sample preparation and the use of synthetic standards can also be extended to the analysis of other polymetallic ores.
In the process of ensemble empirical mode decomposition (EEMD) for motor rolling bearing time series, if the classifier is trained directly using the eigenvalues extracted from the pattern components, there are two shortcomings leading to the reduction of fault identification accuracy as follows: decomposition has serious endpoint effects; the correlation between extracted features lead to the confusion of the fault feature vector classification boundary. Aiming at the problems, in this paper, a fault diagnosis model was built. Firstly, LSTM is used to extend the original data to reduce the divergence degree of the endpoint. Secondly, correlation analysis and dimensionality reduction were carried out for the extracted features to reduce the feature dimension. Finally, the eigenvalues were weighted and genetically optimized to enhance the boundary of different eigenvectors. The experimental results validated by data sets showed that the accuracy of fault diagnosis would be improved by using LSTM extension and genetic optimization feature vector.
The electric motor is an important part of a mobile power station. Under the complex operating conditions, the stiffness of the rolling bearing exhibits strong time-varying characteristics and non-linear characteristics, which is the one of the main sources for the system non-linearity. Taking the angular contact bearing as the research object, the coupled dynamic model of the bearing-rotor system is established to calculate the time-varying stiffness. The bifurcation law exhibited by the system can be attributed to the excitation of the non-linear bearing force. The numerical calculation method is used to study the motion state bifurcation law and dynamic frequency response characteristics under the rated working condition of the motor. Considering bearing damping, clearance and radial load, the bifurcation and time domain diagrams of different parameters, displacements and rotation speeds in different directions are studied respectively. The results show that when the parameters change, the system will experience chaos, quasi-period and period-doubling motion state; Damping suppresses vibration very clearly, while changes in bearing clearance and radial load significantly cause the system’s vibration amplitude to increase, and radial load changes accelerate system vibration. A reasonable bearing is of great significance for motor the design of a mobile power station.
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