Abstract: A hot extrusion die for a special-shaped square pipe includes a die cavity sleeve with a special-shaped cavity. A hot extrusion mandrel is arranged in the die cavity sleeve. An area between the die cavity sleeve and the hot extrusion mandrel forms a die cavity hole. A first extrusion diversion hole and a second extrusion diversion hole are arranged below the die cavity hole. An integral centroid of the die cavity hole is located at a circle center of a radial cross section of the die cavity sleeve. Further disclosed is a hot extrusion integral forming method for a special-shaped square pipe, including: heating and expanding a blank material; heating the blank material again after expanding; performing hot extrusion on the blank material; and cooling the formed special-shaped square pipe in air to a room temperature, and inspecting surface quality and mechanical properties of the special-shaped square pipe.

Abstract: The invention “simulation device and method for studying the influence of wetland plant litter decomposition on water quality”, belongs to the ecological engineering field. The simulation device comprises a distributing reservoir, a planting pool and a discharge bay, and the three are connected successively through a first-level pipeline; the distributing reservoir is used to supply water to the planting pool; the discharge bay is used to collect wastewater discharged from the planting pool; the planting pool comprises a plurality of planting units; the planting unit is a container-like structure and used to hold the planting substrate and plant wetland plants on the planting substrate. By using the simulation device and/or simulation method of the invention, the whole process of the influence of plant litters especially wetland plants litters on water quality under natural state can be highly simulated and restored.

Abstract: A plant seed harvesting device comprises a multi-layer net unit; the multi-layer net unit comprises collecting net, intermediate layer net and bottom layer net; the collecting net, the intermediate layer net and the bottom layer net are all plate-like structure having a plurality of meshes; the peripheral edge of the plate-like structure is a net frame, area with the meshes is net face; The collecting net, the intermediate layer net and the bottom layer net are arranged closely in the axial direction to form the multi-layer net unit; mesh sizes on the collecting net, the intermediate layer net and the bottom layer net are configured to be successively and gradually decreased; plant seeds can pass through the meshes of the collecting net; air but not plant seeds can pass through the meshes of the bottom layer net.

Abstract: The present invention relates to an oil tank ventilation device for a hydraulic brake unit of a tramcar, comprising a vent plug, a sealing ring, a gas guide hole and a gas guide pipe; the gas guide hole is a through-hole structure arranged at an upper end inside an integrated valve block; the communications of electrical element protection case, integrated valve block and the oil tank are realized by the gas guide pipe stretched into an air chamber of the oil tank and by the vent plug configured in the electrical element protection case. When the surface of the oil tank is covered with ice or snow, the rain or snow can be effectively prevent from falling on the vent plug body and the driving safety of the train is ensured.

Abstract: The invention “simulation device and method for studying the influence of wetland plant litter decomposition on water quality”, belongs to the ecological engineering field. The simulation device comprises a distributing reservoir, a planting pool and a discharge bay, and the three are connected successively through a first-level pipeline; the distributing reservoir is used to supply water to the planting pool; the discharge bay is used to collect wastewater discharged from the planting pool; the planting pool comprises a plurality of planting units; the planting unit is a container-like structure and used to hold the planting substrate and plant wetland plants on the planting substrate. By using the simulation device and/or simulation method of the invention, the whole process of the influence of plant litters especially wetland plants litters on water quality under natural state can be highly simulated and restored.

Abstract: A plant seed harvesting device comprises a multi-layer net unit; the multi-layer net unit comprises collecting net, intermediate layer net and bottom layer net; the collecting net, the intermediate layer net and the bottom layer net are all plate-like structure having a plurality of meshes; the peripheral edge of the plate-like structure is a net frame, area with the meshes is net face; The collecting net, the intermediate layer net and the bottom layer net are arranged closely in the axial direction to form the multi-layer net unit; mesh sizes on the collecting net, the intermediate layer net and the bottom layer net are configured to be successively and gradually decreased; plant seeds can pass through the meshes of the collecting net; air but not plant seeds can pass through the meshes of the bottom layer net.

Abstract: The present invention relates to an oil tank ventilation device for a hydraulic brake unit of a tramcar, comprising a vent plug, a sealing ring, a gas guide hole and a gas guide pipe; the gas guide hole is a through-hole structure arranged at an upper end inside an integrated valve block; the communications of electrical element protection case, integrated valve block and the oil tank are realized by the gas guide pipe stretched into an air chamber of the oil tank and by the vent plug configured in the electrical element protection case. When the surface of the oil tank is covered with ice or snow, the rain or snow can be effectively prevent from falling on the vent plug body and the driving safety of the train is ensured.