Abstract: A method of preparing PAN-based carbon fibers relates to the technical field of materials. The method includes: S1. acrylonitrile, a second monomer and an unsaturated UV-sensitive cross-linking agent are mixed, an initiator is then added and a reaction is performed to obtain a meltable PAN-based copolymer; S2. the meltable PAN-based copolymer and a flow modifier are mixed to obtain a mixture, the mixture is extruded and pelletized, and then melt spinning is performed to obtain nascent fibers, the nascent fibers are stretched and annealed to obtain a PAN-based carbon fiber precursor; S3. ultraviolet irradiation is performed on the PAN-based carbon fiber precursor; S4. the PAN-based carbon fiber precursor after ultraviolet irradiation is pre-oxidized and carbonized to obtain PAN-based carbon fibers.

Abstract: Disclosed is a winding method using an air expansion structure, which accurately controls the winding process by preset inflation parameter values and preset winding parameter values, so as to create space for a membrane to contract after winding, that is, to relieve the stress of the membrane, so as to avoid the situation of deviation or innermost side wrinkling during winding of the membrane, and the rewinding procedure is not needed, so that the complexity of the working procedure is reduced.

Abstract: An apparatus for launch and recovery of an Unmanned Aerial Vehicle (UAV), a method for launching a UAV, a method for recovering a UAV and a kit of parts for launch and recovery of a UAV. The apparatus comprises a boom having a center member for receiving the UAV, and first and second arm members extending outwardly and upwardly from the center member, wherein the boom is configured to be lifted to a predetermined height into the air from a reference point; and wherein the boom is movable in the air to an operating position forward of the reference point.

Abstract: An apparatus for launch and recovery of an Unmanned Aerial Vehicle (UAV), a method for launching a UAV, a method for recovering a UAV and a kit of parts for launch and recovery of a UAV. The apparatus comprises a boom having a center member for receiving the UAV, and first and second arm members extending outwardly and upwardly from the center member, wherein the boom is configured to be lifted to a predetermined height into the air from a reference point; and wherein the boom is movable in the air to an operating position forward of the reference point.