A new method had been proposed in this paper of fault diagnosis for rolling bearings based on multichannel vibration signals and QPCA-SVM-based method. The vibration signals were obtained by some multi-sensors with three channels X, Y, Z, that were orthogonal axes. The three orthogonal axes signals were constructed a pure quaternion sequences as samples for processing. The pure quaternion sequences data set was processed by quaternion principle components analysis (QPCA) for feature extraction, and then combined with pattern recognition tools support vector machine (SVM) for classifying some faults patterns. The experimental results indicated its efficiency, and it provided a method for fault diagnosis on multichannel vibration signals.
Solar photovoltaic cell demand is great in the whole world and its manufacturing cost is also high. The main reason that slicing cost is too high, because of the low slicing efficiency and large kerf loss.Therefore, many scholars are studying new slicing method in order to reduce the cost. In this paper, we summarize conventional and new slicing method for solar silicon wafer, and think that new slicing method widely apply in photovoltaic industry, which needs to solve some technical problems. At present, multi-wire saw technology still is mainly slicing method in photovoltaic industry.
The wire saw for slicing wafers process is free abrasive machining process. In this paper, we summarize the sawing mechanism for free abrasive wire saw, and think that the sawing mechanism is mainly rolling-indenting removal. But there are two forms of the force which causing the abrasives to roll and indent in the workpiece surface, one form the force acts on the abrasives by shear stress and hydrodynamic pressure, another form the force acts on the abrasives by wire saw. We design an experiment to verify the form of the force, and think that the second form of the force mainly causes the abrasive to roll and indent in the workpiece surface.
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