39results about How to "Reduce return loss" patented technology

A printed antenna includes a feed portion and a radiating portion. The feed portion feeds electromagnetic signals, and includes a feed end and a connection end. A width of the feed portion is gradually increased from the feed end to the connection end. The radiating portion includes a first radiator and a second radiator. The first radiator is elongated, and connects to the connection end of the feed portion. One end of the second radiator is connected to the first radiator, and the other end is free. The free end is bend and bent along the feeding portion, and defines a slot between the second radiator and the first radiator and the feeding portion.

A radome for an antenna is provided as a composite of an isotropic outer layer and a structural layer of foamed polymer material. The composite is dimensioned to enclose an open end of the antenna. The radome may be retained upon the antenna by a retaining element and fasteners. The outer layer may be a polymer material with a water resistant characteristic.

The invention discloses a method for identifying and positioning an abnormal sound position of an aero-engine, which is used for accurately positioning the position where the aero-engine generates theabnormal sound. The method comprises the following steps: respectively mounting sensors at multiple positions of the aero-engine; acquiring an abnormal sound signal; performing format conversion on the acquired abnormal sound signal; and analyzing and processing the abnormal sound signal after conversion format so as to determine the accurate abnormal sound position. The method and a system for identifying and positioning the abnormal sound position of the aero-engine provided by the invention can avoid the situation that the aero-engine returns to the factory for repair due to wrong judgment, reduce unnecessary return loss, greatly reduce the maintenance cost of the aero-engine, and greatly improve the maintenance efficiency of the aero-engine.

Proposed is a device for the combined rolling and pressing of a cast billet, which comprises a roll with a groove and a roll with a projection, which from a working roll opening, at the exit from which there is disposed a die, mounted in the slot of a die holder. The upper part of the projection on a roll has a T-shaped surface. The roll with a groove comprises projections, and the roll with a projection comprises slots, which are arranged in relation to one another such that the projections and grooves enable a labyrinthine engagement of the rolls. The die is designed such that it can be fixed in position relative to the die holder with the aid of mating slots and projections provided in the die and the die holder. Gaps are provided for in the working roll opening between the surfaces ofthe rolls and the die. The device further comprises a device for adjusting the temperature of the cast billet that is being fed in, said device being mounted upstream of the rolls. During implementation of the method for the combined rolling and pressing of metals or alloys, a cast billet with a pre-set temperature is fed into the working roll opening for rolling and then into a die for pressing.As the cast billet is fed into the roll opening, a cladding layer of a metal or alloy is formed on the surfaces of the rolls as a result of the cast billet being squeezed through the gaps formed between the surfaces of the rolls and the die. The present invention provides an improvement in the quality of the resulting long components, and also an increase in the efficiency of the process as a whole.

The invention relates to an energy-saving and environment-friendly double-backflow type swimming pool, and belongs to the technical field of physical fitness facilities. The swimming pool comprises a swimming pool body and a backflow duct, wherein the swimming pool body comprises a rectangular pool wall, and the backflow duct is located on the periphery of the swimming pool body. A set of parallel diversion pipes are arranged on a part of the pool wall, wherein the part is located at the end, in the length direction, of the swimming pool body. A set of parallel backflow pipes are arranged on a part of the pool wall, wherein the part is located at the other end, located in the length direction, of the swimming pool body. A propeller driven by a propeller shaft is arranged in each diversion pipe. The outer end of each propeller shaft is connected with a corresponding drive motor in a transmission mode, wherein the corresponding drive motor is arranged outside the backflow duct. Preset swirling flow pieces are fixed to the inlet ends of the diversion pipes, wherein the number of the preset swirling flow pieces is the same as the number of propeller wing pieces. A rectification grating is arranged at the outlet ends of the diversion pipes. The preset swirling flow pieces are in the spiral shape in the direction opposite to the direction of the propeller. By means of the energy-saving and environment-friendly double-backflow type swimming pool, water flow entering the diversion pipes can deflect by a certain angle in advance to offset the water flow deflection angle generated when the propeller rotates, and can then be rectified by the grating, so that water flow stable and consistent in output flow direction is output through the diversion pipes, and the comfort degree in the reverse-flow swimming process is ensured.

A radome for an antenna is provided as a composite of an isotropic outer layer and a structural layer of foamed polymer material. The composite is dimensioned to enclose an open end of the antenna. The radome may be retained upon the antenna by a retaining element and fasteners. The outer layer may be a polymer material with a water resistant characteristic. The structural layer may project inward and / or outward with respect to a plane of the seating surface of the radome.

The patent of the present invention discloses a vapor chamber with a composite capillary core structure of metal foam and copper powder. Its main body is a vacuum chamber composed of an upper cover and a lower cover. There is a composite capillary core composed of foam metal and copper powder in the cavity. The structure is filled with a certain amount of low temperature boiling heat transfer fluid. The upper and lower covers are made of deoxidized copper plates. Composite capillary core structure is composed of metal foam plate and copper powder of a certain size through solid phase sintering. Compared with the traditional capillary core structure, it has significant advantages such as large capillary force in the lower layer, small penetration resistance in the upper layer, precise control of capillary force, and small contact thermal resistance; The capillary core structure of the upper and lower cover plates can be designed as one, which improves the return capacity. Compared with the traditional products, the vapor chamber with the composite capillary core structure of metal foam and copper powder has the advantages of low cost, high heat dissipation efficiency and long service life under the same heat dissipation effect.