33results about How to "To achieve the purpose of sound absorption" patented technology

The invention relates to a composite sound absorbing device with a built-in resonant cavity. The device comprises a perforated plate with a plurality of first holes, a back plate and a side plate, wherein a sealed cavity is formed by the perforated plate, the back plate and the side plate. The device is characterized in that at least one or more resonant cavities are placed in the sealed cavity; the resonant cavity is provided with at least one or more second holes; at least one of the second holes is communicated with the sealed cavity; the volume V of the resonant cavity is equal to 10mm3-1*1,010mm3, and the thickness of the wall of the cavity is 0.05 to 10 mm; and the aperture d, of the second hole on the cavity is equal to 0.05 to 100 mm, and the perforated percentage sigma, is 0.01 to 30 percent. The device forms acoustic scattering in the sealed cavity through the resonant cavity; and the second hole increases the acoustic resistance and the multi-cavity coupling resonance. The device has a flexible design and contributes to improving sound absorbing effect and expanding the sound absorbing frequency band.

The invention relates to the technical field of building maintenance structures, in particular to a noise-reduction structure of an outside wall of a building. The noise-reduction structure comprisesa sound absorption unit, wherein the sound absorption unit comprises a box body fixedly arranged on the outside of a wall body. An opening is formed in the box body, and a sound absorption plate is covered on the opening. A plurality of water storage cavities are formed in the sound absorption plate and a water flow channel is arranged on the sound absorption plate. A moving plate is arranged at the side, face to the box body, of the sound absorption plate, wherein thermal expansion blocks are connected between the moving plate and the sound absorption plate, and first water absorption cottonslivers and second water absorption cotton slivers extending into the water storage cavities are arranged in the water flow channel. A limiting plate is parallelly arranged on the side, far from the sound absorption plate, of the moving plate, and the limiting plate is fixedly connected with the box body. The upper ends of the second water absorption cotton slivers horizontally pass through the moving plate and are arranged between the moving plate and the limiting plate. A plurality of horizontal conduits are arranged on the side wall, face to the moving plate, of the limiting plate in an embedded mode, and a plurality of drain holes are formed in the side, face to the moving plate, of the conduits. The noise-reduction structure of the outside wall of the building solves the problem thatthe noise-reduction effect of the outside wall of the building is poor in the prior art.

The invention discloses a general-purpose portland cement-based ultra-light physical foaming foam concrete, which is characterized in that: the components and weight percentages are 20%-70% of general-purpose Portland cement, and 0-40% of A-type admixtures % or / and B-type admixture 0-40%, C-type admixture 0.5%-4%, foaming agent 0.3%-2%, water reducing agent 0-1%, fiber 0-4%, and water 25% ~60% is made by mixing, molding and curing. The universal Portland cement-based ultra-light physical foaming foam concrete of the present invention has the characteristics of ultra-low dry density, low thermal conductivity, high strength, wide source of raw materials, low cost, simple preparation process, and easy selection of maintenance process; it is suitable for As insulation engineering, floor heating engineering, backfill engineering, anti-seismic energy-absorbing, lightweight cushion, catalyst carrier materials, it is especially suitable for external wall insulation systems, roof insulation systems, composite insulation walls, and buffer energy-absorbing systems.

The invention relates to schoolyard fitness equipment, comprising a seat and a block; the back of the seat is provided with a backrest which is provided with a safety belt, a first support is mounted at the bottom of the seat, the first support is mounted in a second support, the lower end of the second support is mounted on the base, the second support is fitted with a shaft sleeve, a cylindrical transverse shaft is mounted in the shaft sleeve, a cylindrical plug is connected to the front end of the transverse shaft, the cylindrical plug is fixedly mounted at the lower end of a vertical shaft, the block is arranged in front of the vertical shaft and is fixedly connected to the vertical shaft through a horizontal cylindrical shaft, the rear end of the transverse shaft is fixedly connected with a cylindrical transverse bar, a rectangular first elongated bar is fixedly connected to the left end of the transverse bar, a rectangular second elongated bar is fixedly connected to the right end of the transverse bar, the first elongated bar, the seat and the second elongated bar are connected through bolts, the upper lateral side of the first elongated bar and the upper lateral side of the second elongated bar are provided with two cylindrical handles respectively. The schoolyard fitness equipment is simple in structure, durable and handy, and effective to use.

The invention provides a preparation method for preparing a nylon porous material on a large scale. The preparation method is characterized in that the selected raw material is nylon, the preparation process is simple and efficient, water in the production process can be repeatedly utilized, and the preparation method conforms to the environment-friendly concept. The nylon is dissolved by using anhydrous formic acid, and a sodium bicarbonate solution is added for foaming to obtain the porous material which is of a three-dimensional porous structure and has excellent performance. The prepared nylon porous material has the advantages of being low in density, high in porosity, low in heat conductivity, high in specific surface area and the like. Compared with aerogel and other porous materials, the preparation method for preparing the porous material is simple, and low-cost large-scale production can be achieved. The method can be used in heat preservation, heat insulation, marine petroleum pollution treatment, catalyst carriers, sound absorption and shock absorption buffer materials and other fields, and has wide application prospects.