Abstract: Disclosed are a visualization grouting device for coal and rock fissures and a test method, a test device including a visualization fissure grouting box body, a box body bracket, a grouting device and a monitoring device. A bottom plate is divided into four identical areas, rubber cushion blocks with different specifications are arranged to simulate different fissure widths and tortuosity, artificial protolith thin film is pasted inside, and a grouting hole and a plurality of pressure measuring holes are arranged in the center of the upper top plate. In the present disclosure, the grouting process of fissures under different grouting conditions, such as different fissure widths, roughness, grouting resistance and tortuosity of pore channels can be simulated, the grouting under different fissure conditions can be simultaneously simulated, and the differences of different grouting diffusion forms can be clearly and intuitively analyzed and compared through the visualization box body.

Abstract: An antenna includes a substrate and a dipole antenna disposed on a surface of the substrate. The dipole antenna includes a first metal structure and a second metal structure arranged symmetrically with respect to each other. The first metal structure includes a head proximal to the second metal structure, and a tail distal from the second metal structure. A width of the first metal structure varies between the head and the tail.

Abstract: An unmanned aerial vehicle (UAV) includes a fuselage, a power system arranged at the fuselage, and an antenna assembly arranged at the fuselage. The antenna assembly includes an antenna operating in a first frequency band and a second frequency band different from each other, a first parasitic unit configured to change a radiation direction of the antenna in the first frequency band, and a second parasitic unit configured to change a radiation direction of the antenna in the second frequency band.

Abstract: A UAV system includes a remote controller including two first antennas and a UAV including two second antennas arranged at two landing stands of the UAV, respectively. The two first antennas and the two second antennas are configured to establish a 2×2 MIMO communication link. The remote controller is configured to transmit current terminal position information of the remote controller to the UAV via the 2×2 MIMO communication link. The UAV determines current remote controller relative position information of the remote controller relative to the UAV according to the current terminal position information and current UAV position information acquired via a position sensor, and controls communication between the UAV and the remote controller according to the current remote controller relative position information.

Abstract: A horizontal distance of an unmanned aerial vehicle (UAV) relative to a remote control device and a height of the UAV relative to the remote control device are obtained. A remote control distance is calculated based on the horizontal distance and the height. It is determined whether the remote control distance increases or decreases. At least one of a first signal transmission power of the UAV or a second signal transmission power of the remote control device is controlled according to a result of the determination. The at least one of the first signal transmission power or the second signal transmission power is increased or maintained in response to determining that the remote control distance increases. The at least one of the first signal transmission power or the second signal transmission power is decreased or maintained in response to determining that the remote control distance decreases.

Abstract: An unmanned aerial vehicle (UAV) antenna with optimal omni-directionality may include a first antenna module, a second antenna module, and a third antenna module. The first antenna module and the second antenna module are arranged opposite to each other, and the third antenna module is arranged on a side of the second antenna module which is away from the first antenna module. The first antenna module includes a first strip line feed and a first oscillator unit electrically connected to the first strip line feed; the second antenna module includes a second strip line feed and a second oscillator unit electrically connected to the second strip line feed; the third antenna module includes a third strip line feed and a third oscillator unit electrically connected to the third strip line feed; the third strip line feed is electrically connected to the second strip line feed.

Abstract: A UAV includes a frame, and multiple propelling devices, a flight control system, an image capturing device, and an antenna that are provided at the frame. The flight control system communicates with the propelling devices and controls the propelling devices to provide power for flight. The antenna includes two oppositely arranged antenna assemblies. Each antenna assembly includes a feed band, and an oscillator including a first frequency band branch, a second frequency band branch, and a third frequency band branch arranged side by side on a side of the feed band. The second frequency band branch is between the first frequency band branch and the third frequency band branch. The second frequency band branch is shorter than the first frequency band branch but longer than the third frequency band branch. The first frequency band branch includes a main body and a bending part at an end of the main body.

Abstract: A method is provided for controlling a signal transmission power of at least one of an unmanned aerial vehicle (“UAV”) or a remote control device. The method includes determining whether a remote control distance between the UAV and the remote control device increases or decreases. The method also includes increasing or maintaining a signal transmission power of at least one of the UAV or the remote control device if the remote control distance increases. The method further includes decreasing or maintaining the signal transmission power of at least one of the UAV or the remote control device if the remote control distance decreases.

Abstract: The present disclosure relates generally to contact lenses having a space within the lens. In various embodiments, a contact lens comprises a posterior component having an anterior surface and an anterior component having a posterior surface. The posterior component and the anterior component can comprise various combinations of gas permeable and gas impermeable optical materials. A contact lens also comprises a space between the posterior surface and the anterior surface, with the space configured to permit diffusion of a gas from a perimeter of the space through the space and across the anterior surface of the posterior component.

Abstract: A UAV system includes a remote controller including two first antennas and a UAV including two second antennas arranged at two landing stands of the UAV, respectively. The two first antennas and the two second antennas are configured to establish a 2×2 MIMO communication link. The remote controller is configured to transmit current terminal position information of the remote controller to the UAV via the 2×2 MIMO communication link. The UAV determines current remote controller relative position information of the remote controller relative to the UAV according to the current terminal position information and current UAV position information acquired via a position sensor, and controls communication between the UAV and the remote controller according to the current remote controller relative position information.

Abstract: An antenna automatic alignment method for a rotor unmanned aerial vehicle (UAV) includes acquiring current feature information of a plurality of antennas of the rotor UAV in real time. The antennas are disposed at substantially U-shaped landing gears of the rotor UAV. The method further includes selecting one of the antennas to establish a point-to-point communication link with a remote controller of the rotor UAV in accordance with the current feature information of the plurality of antennas. The antennas include spare antennas and current communication antennas, and a number of the spare antennas equals a number of the current communication antennas.

Abstract: An antenna automatic alignment method for a mobile object includes acquiring, in real time, current feature information of a plurality of antennas of the mobile object, and selecting one of the antennas to establish a communication link with a wireless terminal in accordance with the current feature information of the plurality of antennas.

Abstract: A method is provided for controlling a signal transmission power of at least one of an unmanned aerial vehicle (“UAV”) or a remote control device. The method includes determining whether a remote control distance between the UAV and the remote control device increases or decreases. The method also includes increasing or maintaining a signal transmission power of at least one of the UAV or the remote control device if the remote control distance increases. The method further includes decreasing or maintaining the signal transmission power of at least one of the UAV or the remote control device if the remote control distance decreases.

Abstract: An unmanned aerial vehicle (UAV) includes a fuselage, a power system arranged at the fuselage, and an antenna assembly arranged at the fuselage. The antenna assembly includes an antenna operating in a first frequency band and a second frequency band different from each other, a first parasitic unit configured to change a radiation direction of the antenna in the first frequency band, and a second parasitic unit configured to change a radiation direction of the antenna in the second frequency band.

Abstract: An antenna includes a substrate and a dipole antenna disposed on a surface of the substrate. The dipole antenna includes a first metal structure and a second metal structure arranged symmetrically with respect to each other. The first metal structure includes a head proximal to the second metal structure, and a tail distal from the second metal structure. A width of the first metal structure varies between the head and the tail.

Abstract: An antenna automatic alignment method for a rotor unmanned aerial vehicle (UAV) includes acquiring current feature information of a plurality of antennas of the rotor UAV in real time. The antennas are disposed at substantially U-shaped landing gears of the rotor UAV. The method further includes selecting one of the antennas to establish a point-to-point communication link with a remote controller of the rotor UAV in accordance with the current feature information of the plurality of antennas. The antennas include spare antennas and current communication antennas, and a number of the spare antennas equals a number of the current communication antennas.

Abstract: The present disclosure relates generally to contact lenses having a space within the lens. In various embodiments, a contact lens comprises a posterior component having an anterior surface and an anterior component having a posterior surface. The posterior component and the anterior component can comprise various combinations of gas permeable and gas impermeable optical materials. A contact lens also comprises a space between the posterior surface and the anterior surface, with the space configured to permit diffusion of a gas from a perimeter of the space through the space and across the anterior surface of the posterior component.

Abstract: An antenna automatic alignment method for a mobile object includes acquiring, in real time, current feature information of a plurality of antennas of the mobile object, and selecting one of the antennas to establish a communication link with a wireless terminal in accordance with the current feature information of the plurality of antennas.

Abstract: Multifocal contact lenses and methods and uses are described. The multifocal contact lenses include an optic zone. The optic zone has an aspheric power profile that provides a near vision refractive power and a distance vision refractive power, and provides an Add power that corresponds to the difference between the near vision refractive power and the distance vision refractive power. The multifocal contact lenses can improve binocular vision of presbyopic subjects by being prescribed such that the non-dominant eye contact lens is over-corrected for distance vision, and both multifocal contact lenses are under-corrected for the Add power requirement of the subject. Batches and sets of multifocal contact lenses are also described.