Abstract: A high-acoustic-resistance piston motion loudspeaker disclosed in the present disclosure belongs to the field of sound-electricity conversion. The loudspeaker includes a substrate, a driving assembly, a vibrating diaphragm, a connecting assembly and a vibration cavity. The connecting assembly is not coplanar with the vibrating diaphragm, which is of a concealed connecting structure. The driving assembly is configured to drive the vibrating diaphragm to generate a piston motion. The vibrating diaphragm is located in the vibration cavity, and a displacement range of the vibrating diaphragm in a perpendicular direction is within a height range of the vibration cavity formed by a supporting structure extending in a thickness direction of a base, so as to achieve purposes of reducing air leakage and improving a sound pressure level in a working process of the loudspeaker.

Abstract: A multi-chip interconnection package structure with a heat dissipation plate and a preparation method thereof are provided. The multi-chip interconnection package structure with a heat dissipation plate includes a fine circuit layer, at least one die, a heat dissipation plate, a plastic package body, and a package circuit layer, the heat dissipation plate is provided on the fine circuit layer, and is mounted on a side of the die away from the fine circuit layer, the plastic package body wraps the die and the heat dissipation plate, and the package circuit layer is provided on the plastic package body.

Abstract: A triboelectric nanogenerating device is configured for providing an electric power to an electronic device and the triboelectric nanogenerating device includes at least one scaly triboelectric membrane configured for providing the electric power to the electronic device by frictional electrification. The at least one scaly triboelectric membrane includes a keratin and a polyvinyl alcohol, the at least one scaly triboelectric membrane has a first triboelectric surface, and the first triboelectric surface of the at least one scaly triboelectric membrane includes a plurality of scaly layers. Each of the scaly layers is arranged in order and extends along an orienting direction. A distal end of each of the scaly layers has a plurality of saw-tooth structures.

Abstract: A tracer particle spreading device for a boundary layer flow visualization experiment based on a flat plate includes a tracer particle generator, a smoke storage box, and a wall-surface particle distribution box. Fume and oil are pressurized by a micro pump and flows into a heating pipe to be heated and vaporized, and then is ejected from a nozzle to form tracer particles. The tracer particles enter the smoke storage box via a smoke guiding tube. An axial flow fan is mounted on a wall surface of the smoke storage box. The tracer particles enter a cavity of the wall-surface particle distribution box via the smoke guiding tube, and the tracer particles are rectified by a rectifying plate and ejected from a spreading slit. An outlet of the spreading slit is at an angle of 15° with respect to an experiment flat plate.

Abstract: A radiographic inspection device and a method of inspecting an object are provided. The radiographic inspection device includes a support frame, where an inspection space applicable to inspect an object is formed within the support frame, and the inspection space has a first opening connecting to an outside; a transfer mechanism applicable to carry the object and move through the inspection space; a shielding curtain mounted at the first opening; and a driving mechanism. The driving mechanism includes: a driver mounted on the support frame; and a joint portion, where an upper end of the shielding curtain is connected to the joint portion. The driver is configured to synchronously drive two ends of the joint portion, so that the shielding curtain moves up and down with the joint portion to open or close the first opening.

Abstract: A method for polyculture of Alosa sapidissima and Macrobrachium rosenbergii by a floating net fishing device and a greenhouse earthen pond includes: S1: providing a slope on an inner wall of a pond, and providing a feeding channel on the slope for survival and attachment of the Macrobrachium rosenbergii; S2: building a greenhouse on the pond, raising a water temperature to a set temperature, then putting Macrobrachium rosenbergii larvae, and putting Alosa sapidissima fry into the pond for polyculture in different periods; and S3: fishing in batches through a floating net: firstly, fishing the Alosa sapidissima fry in middle and upper layers, and then fishing the Macrobrachium rosenbergii in middle and lower layers.

Abstract: The present disclosure discloses a wheel rim finishing device. A motor is fixedly mounted on a stand through a shaft sleeve I. A supporting body is arranged on the stand. The side, close to a locating disk, of the supporting body is provided with an outer roller. An inner driving roller body and an inner driven roller body are arranged at a position, close to the outer roller, on the inner side of the locating disk. The wheel rim finishing device is simple in structure and high in universality, and may adapt to wheel types with different rim structures.

Abstract: A distributed composite refrigeration system includes a multichannel heat exchanger and at least two refrigeration units. The at least two refrigeration units are connected to at least two indoor areas in one-to-one correspondences. Each refrigeration unit includes a refrigeration part, a heat exchange part, and a heat dissipation part. A refrigerant flows between the refrigeration part and the heat exchange part, an intermediate medium flows in the heat exchange part, and the refrigerant and the intermediate medium implement heat exchange at the heat exchange part. The heat exchange part delivers the intermediate medium obtained after heat exchange to the heat dissipation part and/or the multichannel heat exchanger for heat dissipation. The multichannel heat exchanger is thermally connected to an external pipe network, and the intermediate medium performs heat exchange with a heat carrying body in the external pipe network.

Abstract: A composite refrigeration system includes a refrigeration part, a heat dissipation part, a first pipeline, a second pipeline, and a refrigerant. The refrigeration part uses the refrigerant to cool air sent into indoor space, and the heat dissipation part is configured to perform heat dissipation on the refrigerant. In addition, in two heat dissipation modes, the heat exchanger may exchange heat between the refrigerant and a heat carrier in an external pipeline network to implement heat dissipation. The composite refrigeration system implements, by using the heat exchanger, a function of exchanging heat with the external pipeline network, so that heat generated during operation of the composite refrigeration system can be at least partially transferred to the heat carrier in the external pipeline network, to implement the energy recycle and reuse.

Abstract: The disclosure provides a micro-groove drag reduction flexible film and a preparation method thereof. The micro-groove film has a triangular groove structure on the upper surface along the direction of an air flow, and an adhesive layer on the lower surface for quick adhesion to an aircraft surface. After the surface of the aircraft is covered with a micro-groove film, it could limit the spanwise movement of the bottom air at the boundary layer of the aircraft surface, improve the flow field characteristics of the aircraft near the wall, and effectively reduce the frictional resistance of the wall. The micro-groove flexible film is prepared by a roller hot pressing method. The triangular groove structure is processed on the surface of the mold roller of the double roller hot press. After pretreatment of the thermoplastic polyurethane (TPU) polymer film, a micro-groove structure is hot-pressed on the surface of the TPU film.

Abstract: An on-line space detecting device for wheel inner, which comprises a frame, a servo motor A, a synchronous gear A, a bottom plate, a synchronous belt, a synchronous gear B, a base, a connecting shaft, a servo motor B, a shaft sleeve A, a lower end cap, a connecting shaft B, a shaft sleeve B, an oil cylinder, a bearing A, an end cap, a gland, bearings B, a chassis, a flange, a locating pin, springs, rising flaps, a connecting shaft C, a protection, a rising core etc., the present disclosure can meet the needs of the space detection for wheel inner, and has the characteristics of simple structure, convenient manufacture, stable performance and precision of meeting the processing requirements, and can meet the needs of automatic production.

Abstract: A tracer particle spreading device for a boundary layer flow visualization experiment based on a flat plate includes a tracer particle generator, a smoke storage box, and a wall-surface particle distribution box. Fume and oil are pressurized by a micro pump and flows into a heating pipe to be heated and vaporized, and then is ejected from a nozzle to form tracer particles. The tracer particles enter the smoke storage box via a smoke guiding tube. An axial flow fan is mounted on a wall surface of the smoke storage box. The tracer particles enter a cavity of the wall-surface particle distribution box via the smoke guiding tube, and the tracer particles are rectified by a rectifying plate and ejected from a spreading slit. An outlet of the spreading slit is at an angle of 15° with respect to an experiment flat plate.

Abstract: A dragonfly-like miniature four-winged ornithopter includes: a fuselage (101), two front flapping wings (102), two front wing connectors (103) with first connecting rods, two rear flapping wings (104), two rear wing connectors (105) with second connecting rods, a driving gear (106), a shaft gear (107), a first-stage gear (108), two second-stage gears (109) with third connecting rods, two third-stage gears (114) with fourth connecting rods, two front ball joint connecting rods (110), two rear ball joint connecting rods (111), two steering engine connecting rods (112), two steer engines (113), and a brushless direct current motor.

Abstract: The present disclosure discloses an energy management system suitable for a solar-powered unmanned aerial vehicle and a control method thereof, which are used for an aerospace vehicle energy system. The system comprises a photovoltaic module, an MPPT controller, a first DC-DC circuit, a battery pack, a first anti-reverse circuit, a second DC-DC circuit, a second anti-reverse circuit, an ESC, a BLDC, an on-board controller, a communication link and a voltage stabilizing module. During cruising, the battery pack directly supplies power to the ESC through the first anti-reverse circuit; when high-power power output is needed, the battery pack supplies power to the ESC through the second DC-DC circuit and the second anti-reverse circuit in sequence, wherein the output voltage of the second DC-DC circuit and the accelerator signal input of the ESC are controlled by the on-board controller.

Abstract: The present disclosure provides an efficient control system and method for a brushless motor with a wide working range, which are applied to an aerospace vehicle energy system. The system of the present disclosure includes a power supplying module, a first DC-DC circuit, a battery pack, a second DC-DC circuit, an anti-reverse-connection circuit, an electronic speed control (ESC), a brushless direct current motor (BLDC), an airborne controller and a communication link. Electric energy from the power supplying module is configured to charge the battery pack via the first DC-DC circuit, and electric energy of the battery pack sequentially flows through the second DC-DC circuit and the anti-reverse-connection circuit to energize the ESC, wherein output voltage of the second DC-DC circuit and throttle signal input of the ESC are controlled in real time by the airborne controller according to a power demand of an aircraft.

Abstract: The present disclosure discloses an energy management system suitable for a solar-powered unmanned aerial vehicle and a control method thereof, which are used for an aerospace vehicle energy system. The system comprises a photovoltaic module, an MPPT controller, a first DC-DC circuit, a battery pack, a first anti-reverse circuit, a second DC-DC circuit, a second anti-reverse circuit, an ESC, a BLDC, an on-board controller, a communication link and a voltage stabilizing module. During cruising, the battery pack directly supplies power to the ESC through the first anti-reverse circuit; when high-power power output is needed, the battery pack supplies power to the ESC through the second DC-DC circuit and the second anti-reverse circuit in sequence, wherein the output voltage of the second DC-DC circuit and the accelerator signal input of the ESC are controlled by the on-board controller.

Abstract: The present disclosure provides an efficient control system and method for a brushless motor with a wide working range, which are applied to an aerospace vehicle energy system. The system of the present disclosure includes a power supplying module, a first DC-DC circuit, a battery pack, a second DC-DC circuit, an anti-reverse-connection circuit, an electronic speed control (ESC), a brushless direct current motor (BLDC), an airborne controller and a communication link. Electric energy from the power supplying module is configured to charge the battery pack via the first DC-DC circuit, and electric energy of the battery pack sequentially flows through the second DC-DC circuit and the anti-reverse-connection circuit to energize the ESC, wherein output voltage of the second DC-DC circuit and throttle signal input of the ESC are controlled in real time by the airborne controller according to a power demand of an aircraft.

Abstract: A manufacturing process for ultrasonic atomization piece relates to the atomization piece technical field and includes: S1. cutting a press-thermosetting conductive adhesive film into a shape matched with a piezoelectric ceramic sheet; S2. placing the press-thermosetting conductive adhesive film on a composite plate, wherein the composite plate includes a substrate and a conductive layer, the press-thermosetting conductive adhesive film is placed on the conductive layer, and the substrate is a polymer film; S3. placing the piezoelectric ceramic sheet on the press-thermosetting conductive adhesive film; S4. pressing the piezoelectric ceramic sheet and the composite plate in S3 together by a press machine. The press-thermosetting conductive adhesive film for connecting the piezoelectric ceramic sheet and the composite plate can be cured in a short time under high pressure and heating and has excellent adhesion, which is a thin film material with excellent plasticity and can be easily cut into various shapes.

Abstract: An ultrasonic atomization piece and manufacturing process thereof relate to the technical field of ultrasonic atomization. The piece comprises a piezoelectric ceramic sheet and at least one composite plate. The composite plate is fixed on one side of the piezoelectric ceramic sheet and includes a substrate and a conductive layer, the conductive layer is in contact with the piezoelectric ceramic sheet, the substrate is provided with atomizing apertures, and the substrate is a polymer film. Compared with the traditional stainless steel thin sheet, the polymer film is used as the substrate material; the force for the piezoelectric ceramic sheet to generate deformation requires being lower, so the piezoelectric ceramic sheet can pull the polymer film to generate deformation with less energy. The difficulty of drilling apertures is reduced, and metal residues splashing will not occur, thereby eliminating the adverse effect of metal residues on the passage efficiency of liquid.

Abstract: The present disclosure provides a numerical control machine and a cutting method. The numerical control machine includes a workpiece seat for fixing a workpiece, a cutting tool, a non-contact measurement component for measuring a contour of a surface to be machined of the workpiece, a power component and a control component. The workpiece seat is rotatable relative to the cutting tool or the non-contact measurement component under driving of the power component, and/or the cutting tool is rotatable relative to the workpiece seat under the driving of the power component. Both the cutting tool and the non-contact measurement component are mounted on the numerical control machine, and distances from the workpiece seat to both is adjustable. The control component is electrically connected with the non-contact measurement component and the power component.