One-step pretreatment, anodization, is used to activate the polyacrylonitrile (PAN)-based carbon fi bers instead of the routine two-step pretreatment, sensitization with SnCl 2 and activation with PdCl 2 . The effect of the anodization pretreatment on the graphitization of PAN-based carbon fi bers is investigated as a function of Ni-P catalyst. The PAN-based carbon fi bers are anodized in H 3 PO 4 electrolyte resulting in the formation of active sites, which thereby facilitates the following electroless Ni-P coating. Carbon fi bers in the presence and absence of Ni-P coatings are heat treated and the structural changes are characterized by X-ray diffraction and Raman spectroscopy, both of which indicate that the graphitization of PAN-based carbon fi bers are accelerated by both the anodization treatment and the catalysts Ni-P. Using the anodized carbon fi bers, the routine two-step pretreatment, sensitization and activation, is not needed.
It is well known that stability, center-of-gravity balance, and concentrated-weight are key factors of the transportation safety. The reasonable formulation of the loading layout scheme ensures the safety of shipment based on fully utilizing the effective volume and load capacity of freight vehicles. This paper takes the railway mixed goods loading layout as the research object, considering the constraints such as goods loading center-of-gravity balance, the allowable moment of concentrated-weight, supporting and goods placement mode, and taking the maximum comprehensive utilization rates for both effective volume and load capacity of freight vehicle as the optimization objective, an optimization model of railway mixed goods balanced and anticoncentrated-weight loading layout considering stability is built. Additionally, this paper designs mixed goods classified and simple/general goods block composition methods. We improve the representation and selection of layout space, construct goods block selection algorithm based on the greedy d-step lookahead tree search and goods block evaluation function and propose a goods block placement strategy and update rules of layout space after goods block placement. An optimization algorithm of railway mixed goods balanced and anticoncentrated-weight load layout considering stability is designed. The results show that the formulated scheme not only ensures that the goods meet the full support constraints, but also the comprehensive utilization rate of the effective volume and load capacity of the vehicle is not less than 89%, and the probability of meeting the loading center-of-gravity balance and allowable moment of concentrated-weight are as high as 99% and 99.47%, respectively. The proposed method realizes the balanced and anticoncentrated-weight loading of railway mixed goods, ensures the safe, stable, and efficient goods loading, and provides decision support for the safe loading layout of railway goods.
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