Abstract: An arc-ablation resistant tungsten alloy switch contact and preparation method is disclosed. A contact member has a three-layer structure, wherein a first layer is a hydrophobic rubber layer, a second layer is a sheet metal layer, and a third layer is a tungsten alloy chemical deposition layer. A plating bath adopted in the chemical deposition contains 25-125 g/L soluble tungsten compound, 0-60 g/L soluble compound of a transition metal like ferrum, nickel, cobalt, copper or manganese, and 0-30 g/L soluble compound of tin, stibium, lead or bismuth. When a layered complex of the hydrophobic rubber layer and the sheet metal layer is chemically plated by the plating bath, a tungsten alloy plated layer is selectively deposited on a metal surface, and chemical deposition of the tungsten alloy does not occur on a surface of the hydrophobic rubber fundamentally.

Abstract: A rotatory energy recycling control device for a hydraulic excavator, comprising: an oil line selector valve (1), a direction selector valve (2), a sequencing valve (3), a one-way valve (4) and an overflow valve (5); two oil inlets of the oil line selector valve (1) are respectively connected to an opening A and an opening B of a rotary motor; an oil outlet of the oil line selector valve (1) is connected to an inlet of the direction selector valve (2); an outlet of the direction selector valve (2) is connected to an net of the sequencing valve (3); a drainage port of the sequencing valve (3) is connected to an oil tank; an outlet of the sequencing valve (3) and an net of the one-way valve (4) communicate with the overflow valve (5): the outlet of the one-way valve (4) is connected to an energy storage and utilization device; and an outlet of the overflow valve (5) is connected to the oil tank.

Abstract: A multi-step method for fabricating a tissue engineering bone comprises the following steps: (1) scaffold repair and pre-vascularization: fabricating a tissue engineering bone scaffold at a bone defect site, and conducting pre-vascularization; and (2) post-implantation of a seed cell for bone tissue engineering: after an inflammatory reaction period, combined with time for micro-vessel in-growth, implanting an osteogenic-induced seed cell into a tissue engineering bone scaffold at the bone defect site. In certain embodiments, the step (2) of post-implantation of a seed cell for bone tissue engineering is performed 7 to 14 days after the step (1) of scaffold repair and pre-vascularization. The method can be used to rapidly fabricate a large section of tissue engineering bone, greatly reduce usage of the seed cell for bone tissue engineering required in repair of per unit volume of bone tissue, and improve the utilization rate of the seed cell.