3results about How to "Protection strength" patented technology

The present invention provides a method for preparing a negative pressure film-covering frozen sand mold. The method includes the following steps: directly obtaining a mold cavity of a sand mold through numerically controlled machining of a frozen sand blank; covering a surface, brushed with a thermal insulation coating, of the mold cavity of the sand mold with a softened thin film, and covering an outer surface of the sand mold with a back film to seal a sand box; fix the frozen sand mold in an air extraction sand box with a vacuum chamber, and extracting air through a vacuum pump, so that the thin film tightly adheres to the sand mold through vacuum suction force; and closing the box to obtain an integral sand mold, and pouring a casting at room temperature or low temperature under negative pressure. The method is environment-friendly, and the prepared frozen sand mold has high strength and is convenient for sand cleaning. During pouring, little vapor is generated, and metal solidifies rapidly, so a casting with good internal quality, high dimensional accuracy, and excellent surface quality can be produced.

The application discloses an indoor distribution optical cable easy to be pulled out laterally for construction, which comprises an outer sheath, two GFRP strips and a plurality of loose tube units; the inner cavity of the outer sheath is only arranged with the plurality of loose tube units, each of which is arranged in the inner cavity of the outer sheath in a straight manner, and each loose tube unit comprises a loose tube and one or more optical fibers; on the cross section of the indoor distribution optical cable, the two GFRP strips have outer common tangent l1 and outer common tangent l2, the inner edges of the outer sheath are respectively divided into two areas by the outer common tangent l1 and l2, and the outer edge of any one of the loose tube units does not exceed the outer common tangent when the outer edges of all the loose tubes enter one area. The application is easy to complete the opening of the skylight construction, so that the loose tube unit is easy to be pulled out, and the optical fiber is not easy to be damaged when the outer sheath is cut.

The utility model relates to the technical field of road structures, in particular to a road structure capable of preventing arch expansion deformation, which comprises a roadbed, an anti-permeation layer, a water-stable base layer and a pavement layer, the anti-permeation layer is paved on the roadbed, the water-stable base layer is paved on the anti-permeation layer, the pavement layer is paved on the water-stable base layer, and the water-stable base layer is paved on the pavement layer. The anti-permeation layer is used for preventing sulfate in the roadbed from permeating into the water-stable base layer. According to the road structure capable of preventing arch expansion deformation provided by the utility model, the impermeable layer is arranged between the roadbed and the water-stable base layer, and the impermeable layer can block the capillary action of sulfate in the salinized soil roadbed, prevent the sulfate in the salinized soil roadbed from permeating into the water-stable base layer and prevent the salt expansion phenomenon of the water-stable base layer; the strength and the stability of the water-stable base layer are protected, the arch expansion phenomenon of the pavement layer is prevented, and the defect that transverse arch expansion cracking of the pavement is prone to occurring in an existing road structure in the salinized soil area is overcome.