55results about How to "Attenuate sonic energy" patented technology

An exhaust noise treatment device for fuel vehicles, comprising an exhaust pipe of the automobile, several first through holes evenly distributed on the side of the exhaust pipe, a first conical cylinder installed inside the exhaust pipe, the large end surface of the first conical cylinder and the exhaust pipe The inside of the trachea is in contact and fit, the second cone is installed inside the first cone, the small end surface of the third cone is fixedly connected with the sleeve, and several countersunk holes are evenly opened on the outside of the third cone. The present invention is suitable for Noise reduction of automobile exhaust, the exhaust exhaust passes through the large end face of the first conical cylinder, the exhaust gas passes through the second through hole from the middle of the ring, and then is discharged into the atmosphere, followed by the exhaust emission and noise, the noise passes through the rotating The first blade reduces the energy of the sound wave, and is reflected inside the first cone, the energy of the sound wave is reduced again, thereby reducing the noise. The device has a simple structure and is easy to disassemble and assemble, which can improve the exhaust emission and improve the efficiency of the engine. , energy saving and emission reduction, reducing exhaust noise can also protect the exhaust pipe to a certain extent.

The invention relates to a low noise centrifugal pump which comprises a volute and an impeller. The low noise centrifugal pump is characterized in that the width and the radius of the volute are enlarged and enlarged space is filled with acoustic materials which are made from rubber or polyurethane; the inner wall of the acoustic materials is attached to the impeller; and the inner edge position of a rubber layer is determined by fluid dynamics characteristics of the design of the low noise centrifugal pump. In low frequency, the filled acoustic materials in an enlarged position can effectively enable acoustic waves to be smoothly spread to enable fluid not to pass through and accordingly an acoustic self-cancellation channel between two monopoles is established to enable a same-amplitude and reversed-phase radiation noise part on the bilateral sides of the impeller to be canceled out. In medium-high frequency, damping of the filled acoustic materials in the enlarged position can convert acoustic energy into heat energy to enable the acoustic energy to be attenuated. The low noise centrifugal pump has the advantages of being simple in implementation process, stable and reliable in structure and capable of reducing flow noise of broadband of the low noise centrifugal pump based on guaranteeing hydrodynamic parameters of the low noise centrifugal pump.

The invention relates to a preferred structure of a high quality factor thin film bulk acoustic resonator, comprising a substrate with a groove on the upper surface, a bottom electrode layer above the substrate, and a piezoelectric layer, and is characterized in that it also includes a The top electrode layer of the special-shaped air bridge structure, which is equipped with an acoustic rebound structure that can rebound the transverse sound wave; the acoustic rebound structure is a convex or opposite bridge cavity of the special-shaped air bridge structure. The trapezoidal polyhedron is arranged horizontally in the area above the bridge cavity of the special-shaped air bridge structure. The top surface of the acoustic rebound structure is embedded and closely attached to the groove on the top surface of the bridge cavity of the special-shaped air bridge structure. The acoustic rebound structure There is an air gap between the bottom end surface and the suspension structure in the area below the bridge cavity of the special-shaped air bridge structure. The left and right sides of the acoustic rebound structure are respectively embedded and adjacent to the bridge cavity support structure of the special-shaped air bridge structure. The grooves on the inner side fit snugly. The invention can significantly improve the quality factor of the film bulk acoustic wave resonator.