Abstract: The present disclosure discloses a method for quantifying a bearing capacity of foundation containing shallow-hidden spherical cavities, comprising: in Step 1, constructing a spatial axisymmetric calculation model for stability analysis of the foundation containing shallow-hidden spherical cavities; in Step 2, solving the model to obtain a general solution which reflects the spatial stress distribution of surrounding rock containing shallow-hidden spherical cavities; in Step 3, obtain a mathematical expression by derivation for calculating the bearing capacity of the foundation containing shallow-hidden spherical cavities; and in Step 4: completing the determination of the foundation bearing capacity. Benefits: This method has many advantages such as comprehensive consideration, high accuracy and reliability of calculation results, and may provide the scientific basis for the development of prevention and control against the instability of the foundation containing shallow-hidden cavities.

Abstract: The present disclosure relates to a device and a system for testing flatness. The device for testing flatness includes a base, a testing platform, and a ranging sensor. The testing platform is assembled on the base. The testing platform includes a supporting structure. The supporting structure is disposed on the side of the testing platform away from the base and is used to support a to-be-tested board. The structure matches the structure of the to-be-tested board. The ranging sensor is disposed on the side of the testing platform away from the base. After the to-be-tested board is placed on the testing platform, the ranging sensor is used to test distances between a number N of to-be-tested positions on the to-be-tested board and the ranging sensor, to obtain N pieces of distance information, and the N pieces of distance information are used to determine the flatness of the to-be-tested board, where N is an integer greater than 2.

Abstract: A folding device is provided. The folding device includes a bearing and fixing mechanism (1) configured to bear and fix a main body portion (21) of a to-be-folded device (2); a folding mechanism (3) located on at least one side of the bearing and fixing mechanism (1), the folding mechanism (3) being rotatably connected to the bearing and fixing mechanism (1) and configured to bear and fix a to-be-folded portion (22) of the to-be-folded device (2); and a driving mechanism (4) connected to the folding mechanism (3), the driving mechanism (4) being configured to drive the folding mechanism (3) to turn relative to the bearing and fixing mechanism (1), so as to fold the to-be-folded portion (22) to a side in a thickness direction of the main body portion (21). The folding device can fold automatically, and manual folding is avoided.

Abstract: The present invention provides a packaging structure and a packaging method for a refrigerator. The packaging structure for a refrigerator comprises a bottom seat supported on a bottom of the refrigerator, a top seat covering a top of the refrigerator, four vertical side edges, and a film layer, wherein the film layer wraps an outer surface of an outline main body formed by the bottom seat, the top seat and the four vertical side edges by means of film shrinking upon heating. The packaging structure and packaging method employ the film which is heated to shrink to form a layer of outer film, the packaging manner of covering the whole refrigerator with paper needn't be employed, and the cost can be saved.

Abstract: A counter-rotating fan, comprising an impeller assembly and an air guide structure. The impeller assembly comprises a first stage impeller and a second stage impeller, of which the rotation directions are opposite. The pressure surfaces of first blades of the first stage impeller are configured to be opposite the suction surfaces of second blades of the second stage impeller, and from the blade root to the blade tip, each of the first blades and the second blades bends toward its own rotation direction. The air guide structure comprises a flow guide cover. The flow guide cover is provided at the center position of the air intake side of the first stage impeller, and the air intake side surface of the flow guide cover at least partially forms a flow guide surface, the flow guide surface extending along the axis of the first stage impeller in the direction away from the counter-rotating fan.

Abstract: A vacuum clear and an electric motor module (100) therefor are provided. The electric motor module (100) includes an outer casing (1) provided with an air inlet (10) at a front side thereof and an air outlet (11) at a rear side thereof; an electric motor assembly (2) arranged in the outer casing (1), and cooperating with the outer casing (1) to define an air passage in communication with the air inlet (10) and the air outlet (11); and a silencer (3) arranged at the air inlet (10), defining at least one resonant cavity therein, and the at least one resonant cavity having a side wall provided with a throat in communication with the resonant cavity.

Abstract: A counter-rotating fan, comprising an impeller assembly and an air guide structure. The impeller assembly comprises a first stage impeller and a second stage impeller, of which the rotation directions are opposite. The pressure surfaces of first blades of the first stage impeller are configured to be opposite the suction surfaces of second blades of the second stage impeller, and from the blade root to the blade tip, each of the first blades and the second blades bends toward its own rotation direction. The air guide structure comprises a flow guide cover. The flow guide cover is provided at the center position of the air intake side of the first stage impeller, and the air intake side surface of the flow guide cover at least partially forms a flow guide surface, the flow guide surface extending along the axis of the first stage impeller in the direction away from the counter-rotating fan.

Abstract: A fan includes a first wind wheel having a first rotation axis and a second wind wheel arranged opposite to the first wind wheel and having a second rotation axis. The first wind wheel includes a first hub and a plurality of first blades arranged around the first hub and spaced apart from one another. The second wind wheel includes a second hub not directly coupled to the first hub and a plurality of second blades arranged around the second hub and spaced apart from one another. The first blades and the second blades are tilted towards opposite directions along a circumferential direction.

Abstract: A vacuum clear and an electric motor module (100) therefor are provided. The electric motor module (100) includes an outer casing (1) provided with an air inlet (10) at a front side thereof and an air outlet (11) at a rear side thereof; an electric motor assembly (2) arranged in the outer casing (1), and cooperating with the outer casing (1) to define an air passage in communication with the air inlet (10) and the air outlet (11); and a silencer (3) arranged at the air inlet (10), defining at least one resonant cavity therein, and the at least one resonant cavity having a side wall provided with a throat in communication with the resonant cavity.

Abstract: The cold-brewed tea beverage bottle includes a bottle cap and a bottle body; a tea container is arranged on an upper portion of the bottle body or the bottle cap; a retaining cap is mounted in the tea container in a clearance fit; a bottom end of the retaining cap is of a zigzag shape, which is just opposite to a seal sheet on a bottom portion of the tea container; a water outlet is formed on an upper portion of the retaining cap; a pushing rod is arranged on the tea container and in the bottle cap; the pushing rod and a force-exerting sealing cap both are in threaded connection with the bottle cap; by rotating the force-exerting sealing cap and pressing down the pushing rod, the retaining cap props against the seal sheet to open, and the tea leaves in the tea container fall into the bottle to soak.