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

The invention discloses general purpose Portland cement based ultra-light physical foamed concrete which is characterized by being prepared by mixing, forming and maintaining the following components in percentage by weight: 20-70% of general purpose Portland cement, 0-40% of a type A admixture or / and 0-40% of a type B admixture, 0.5-4% of a type C additive, 0.3-2% of a foaming agent, 0-1% of a water reducing agent, 0-4% of fibers and 25-60% of water. The general purpose Portland cement based ultra-light physical foamed concrete disclosed by the invention has the characteristics of ultra-low dry density, low thermal conductivity, relatively high strength, wide raw material source, low cost, simple preparation process, easy maintenance process selection and the like, is suitable to serve as an earthquake-proof and energy-absorbing material, a lightweight cushion course and a catalyst carrier material in a thermal insulation project, a floor heating project and a back filling project, and is particularly suitable for a building exterior wall external thermal insulation system, a roof thermal insulation system, a composite thermal insulation wall body and a buffer energy absorbing system.

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 discloses a sound-absorbing sound-insulating composite material for automobiles, consisting of the following raw materials in parts by weight: 6-10 parts of ethylene propylene diene monomer rubber, 6-8 parts of magnesium oxide, 6-9 parts of glass fiber cotton, 0.2-0.6 part of foaming adhesive, 40-50 parts of gypsum mortar, 20-30 parts of diatom mud, 16-20 parts of wood fiber, 3-5 parts of carboxymethyl cellulose, 1-3 parts of stabilizer, 5-9 parts of foaming agent, 14-18 parts of water, 0.5-12 parts of copper oxinate, 15-25 parts of PVC resin, 2-4 parts of n-butanol, 1-3 parts ofcoalescing aid, 1-3 parts of wetting agent, 7-9 parts of zinc oxide, 1-3 parts of calcium carbonate, 4-6 parts of benzoic acid, and 6-10 parts of natural double salt. The sound-absorbing sound-insulating composite material for automobiles of the invention is improved in corrosion resistance; sound energy is gradually attenuated, so that the purpose of sound absorption is achieved, and the porouscharacteristic is used to realize sound absorption and noise reduction; and with addition of diatom mud, toxic volatile organic compounds on the surface of the composite sound-absorbing material are greatly reduced, the environmental friendliness is enhanced, the sound insulation effect is excellent, and the use prospect is better.

The invention relates to a cotton-free non-metallic compound sound barrier and a preparation method thereof. The compound sound barrier is formed by assembling a plurality of barrier single bodies with cavity bodies in an up-down connection mode, each barrier single body is formed by bonding micro-hole rock sound absorbing and insulating boards and groove-shaped cement components, and the cavity bodies are composed of the micro-hole rock sound absorbing and insulating boards and the groove-shaped cement components in an enclosed mode. Production and installation are convenient, connection is conducted without rivets, elegant appearance is achieved, the good sound absorbing property and sound insulating property are achieved, and fire prevention, and weather resistance and durability are achieved. The cotton-free non-metallic compound sound barrier can be widely used in rail way transportation sound insulation, expressway sound insulation, sound insulation of various machines, ceilings, large-sized houses, class rooms and the like. According to the cotton-free non-metallic compound sound barrier and the preparation method thereof, operating humanization and simplification are achieved, maintenance and disassembling are convenient and easy, construction is quick, and manpower and material resources are saved; and meanwhile, the cotton-free non-metallic compound sound barrier can be adaptable to different environment conditions, application prospects are wide, and the cotton-free non-metallic compound sound barrier can be widely used in all industries of the industrial field.

The invention provides an acoustic reinforcing material block as well as a manufacturing method and application thereof. The acoustic reinforcing material block is prepared by taking components including a porous material, a binder, a pore-forming aid or gas, a filler and water as raw materials and adopting a foaming freeze-drying process, a freezing foaming process or a sintering forming process, the acoustic reinforcing material block is internally provided with at least three stages of pore channels, the first-stage pore channels comprise micropores of the porous materials, the second-stage pore channels comprise pore channels formed between the porous materials, between the porous materials and the filler and between the filler and the filler, and the third-stage pore channels comprise cavities formed by pore-forming aid or gas. When the acoustic reinforcing material block provided by the invention is filled in a loudspeaker resonant cavity of the electronic equipment, the volume of the loudspeaker resonant cavity can be virtually increased, so that the loudspeaker can achieve better sound quality under the condition of smaller volume, and has more excellent sound performance.

The invention relates to a light, high-strength sound absorbing board mounted on a wall, and production method thereof, the sound absorbing board provided in the invention is composed of resin, a labyrinth shape via hole structure is provided on a board body; the production method comprises following process: selecting a dissoluble particle accessory material to filter and grade, so as to obtain an even particle framework; providing a mould for receiving and storing the particle framework, and impacting the particle framework; pre-heating a resin material and a curing agent to a pre-heated mould having a fluid sprue particle framework; solidifying and desquamating; putting above product in freshwater to dissolve the dissoluble particle framework, and then drying to obtain a product.

The invention relates to the technical field of preparation of building boards and specifically relates to a preparation method of a high-strength sound-absorbing board. The preparation method provided by the invention is as follows: firstly removing proteins in frozen beancurd to enable the frozen beancurd to be of a porous structure with a large specific surface area, modifying zeolite powder toobtain modified foamed zeolite slurry, smearing the modified foamed zeolite slurry on the surface of fermented beancurd, performing drying treatment, and taking out a porous foamed material, so thatthe porosity of the structure in zeolite is improved and the sound-absorbing effect is further achieved, the filling of the zeolite improves the strength of the sound-absorbing board, and the additionof nano-montmorillonite improves the crystallinity of the material; continuously adding ceramsite, a foaming agent and a waterproofing agent, wherein the foaming agent produces bubbles in the stirring process so as to achieve the sound-absorbing effect, the ceramsite with a certain hardness is filled into the sound-absorbing board to improve the strength, the waterproofing agent enables the sound-absorbing board to have a hydrophobic function, the surface and voids of the sound-absorbing board can be automatically purified, and the sound-absorbing effect is stabilized, so that the preparationmethod has broad application prospects.

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 relates to a low-noise cooling fan for trains. A combined micro-perforated plate is provided in the gap inside the side plate. The combined micro-perforated plate is a plate with microholes of two different sizes. The combined micro-perforated plate and the side plate are provided with There is a support plate for connection; the back of the air inlet and the inner surface of the air outlet are provided with a thin plastic box-type sound-absorbing body, and the thin-plastic box-type sound-absorbing body is a board with convex double-cavity box-type sound-absorbing blocks evenly distributed on the surface; The leaves are perforated. The beneficial effects of the present invention are: the combination of micro-perforated plates is installed to form a resonant sound-absorbing body, and the air molecules in the perforations and the cavity generate vibration friction and consume sound energy; the walls of the thin plastic box-type sound-absorbing body will vibrate, and the During the process, part of the sound energy is converted into heat energy; blade perforation treatment reduces and suppresses the generation of vortex shedding, the separation area of ​​the outlet section of the working wheel will be reduced, the strength and size of the vortex in the wind area will be reduced, and the eddy current noise radiated by the cascade will be reduced accordingly.

The invention discloses a making method of an automobile sound-absorption carpet. The carpet is formed by pressing a layer A, a layer B, a layer C and a layer D from top to bottom at high temperature. The preparation method includes the steps that a, opening, mixing, carding, cross lapping, needling forming and raising shaping are performed on 100% fine Danny PET fibers to form the layer A having excellent sound-absorption performance; b, opening, mixing, carding, cross lapping and needling forming are performed on three-dimensional crimped fibers and L-PET fibers to form the layer B having a certain thickness and a certain tightness degree; c, a three-roll hot ironing machine is used for pasting the PE face of a PEPA asymmetrical film of the layer D to the layer B, and then cooling is performed to form PET bottom felt finally; d, a PE film is used for pasting the fabric of the layer A to the face, without the PEPA asymmetrical film, of the PET bottom felt formed in the step c, so that the automobile sound-absorption carpet is formed. The automobile sound-absorption carpet has the advantage that the fine Danny fibers are adopted for achieving the sound-absorption effect of the product according to requirements.

The present invention discloses a preparation method for preparing Si2N2O-Si3N4-TiN porous ceramics. The method comprises the steps of proportionally adding Si, TiO2 and Al2O3-Re2O3, mixing up, ball milling, and drying to obtain Si-TiO2-Al2O3-Re2O3 mixed powders; and conducting the atmosphere sintering in the nitrogen atmosphere to obtain the Si2N2O-Si3N4-TiN porous ceramics. The porosity of the obtained porous ceramics is up to 60%, and the aperture thereof is between 20 and 150 mum. The obtained porous ceramics can be used as good sound-absorption materials. The hardness of the obtained porous ceramics is 100-800 HV, and the fracture toughness of the porous ceramics is 1-4 MPam1 / 2. The bending strength of the obtained porous ceramics is 50-400 Mpa. Therefore, the obtained porous ceramics is excellent in thermal shock resistance, oxidation resistance and the like. The dielectric constant of the porous ceramics is 3.5-7.0, and the porous ceramics can be used as thermal protection materials and wave-transparent materials in the fields of aerospace, mechanical industry and the like. Meanwhile, the porous ceramics can also be applied to reactors, filters and the like in the fields of automobile exhaust gas treatment and chemical engineering.

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.

A multilayer nested low-frequency broadband sound absorption device based on resonance sound absorption comprises a plurality of resonator units which are nested in sequence, each resonator unit comprises a bottom plate, a shell, a partition plate and a neck short pipe, the partition plates and the bottom plates are arranged at the two ends of the shells respectively, and the neck short pipes arearranged in the centers of the partition plates in a penetrating mode. Multi-order resonance is achieved through mutual coupling between different stages of resonator units, and then the absorption frequency band is broadened. The absorption frequency band is broadened based on the multi-order resonance principle, and the adjustability of the sound absorption coefficient and the absorption peak frequency is improved. Compared with an existing structure, the broadband sound absorption device is small in size and light in weight, has broadband sound absorption performance in a low-frequency range, and has good application prospects and industrial value.

The invention discloses a sound insulation and absorption structure for a fresh air fan, and belongs to the technical field of residence fresh air.The sound insulation and absorption structure comprises an outer layer and an inner layer.The outer layer is in a plane shape.The inner layer is fixedly connected to one side of the outer layer.The end, away from the outer layer, of the inner layer is of a wave structure.The trough positions of the wave structure are evenly provided with sound absorption hole structures.Each sound absorption structure comprises a spherical cavity located in the inner layer and located below the trough of the wave structure.The top end of each spherical cavity is provided with an opening communicated with the corresponding trough of the wave structure.Each sound absorption structure further comprises a cavity located below the corresponding spherical cavity and communicated with the corresponding spherical cavity.Each cavity is filled with a sound absorption material layer.The sound insulation and absorption structure ingrates sound insulation and absorption, can obviously reduce noise, and is high in practicability, simple in structure, smooth in outer surface and easy to machine.

The invention discloses sound-absorbing wallpaper base paper and a preparation method thereof, and belongs to the field of wallpaper preparation. The sound-absorbing wallpaper base paper is prepared from the following components in parts by weight: 30-45 parts of wood pulp fibers, 25-40 parts of sea-island fibers, 10-20 parts of latex, 3-10 parts of PVC paste resin, 1-6 parts of a plasticizer, and0.01-1 part of a foaming agent. According to the preparation method provided by the invention, the prepared sound-absorbing wallpaper base paper forms a structure with a soft and rough outer surfacethrough adding the sea-island fibers, coating a PVC foaming material at the outer surface of the base paper, and performing foaming, a large number of pores are formed in the base paper, sound waves enter the pores and are propagated inwards, the sound waves have the friction function with a material to make sound energy converted into heat energy, so that the purpose of absorbing sound is achieved; and the sound-absorbing wallpaper provided by the invention has an average sound absorption coefficient of greater than 0.45, and belongs to sound-absorbing materials with better sound-absorbing effects.

The invention discloses an asymmetric type matter state self-transfer decoration engineering construction dust fall device which comprises an upper fixing plate, a combined type matter state self-transfer regulation and control device, a nested circulation pipe, an asymmetric type buoyancy self-alarm pore noise reduction device and a lower fixing and supporting device, and the combined type matter state self-transfer regulation and control device is arranged on the bottom wall of the upper fixing plate; the upper end of the nested circulation pipe is arranged on the inner bottom wall of the upper fixing plate, the combined type matter state self-transfer regulation and control device is arranged in the nested circulation pipe, and the asymmetric buoyancy self-alarm pore noise reduction device is movably arranged on the combined type matter state self-transfer regulation and control device. The invention belongs to the technical field of building decoration engineering dust falling, and particularly relates to an asymmetric matter state self-transfer decoration engineering construction dust falling device, in particular to an asymmetric buoyancy self-alarm pore noise reduction device which is arranged in a nesting circulation pipe, and the lower end of the nesting circulation pipe is arranged on a lower fixing and supporting device. And inclination detection on the combined nested runner pipe is realized.

The invention discloses a carpet with a sound absorption function. The carpet comprises two rubber plates, wherein the opposite surfaces of the two rubber plates are fixedly connected with a carpet base, a styrene elastic plate and a substrate; the styrene elastic plate is positioned between the carpet base and the substrate; the upper surface of the carpet base is fixedly connected with a villusbase; villi are filled inside the villus base. Through the arrangement of the styrene elastic plate, slicing holes, elastic balls and a telescopic device, the styrene elastic plate is an elastic plateand can be used for weakening the sound waves; when the sound enters the silencing holes, the six surfaces of the silencing holes continuously reflect the sound waves; the sound waves are continuously weakened; the styrene elastic plate, the elastic balls and the telescopic device are used, so that the carpet has the elasticity; the problems that the sound absorption effect of the carpet is not ideal, the elasticity is poor, a quiet and comfortable environment cannot be provided for people, and the reading, writing and spare time learning, study and work of people are influenced can be solved.

The invention discloses a sound insulation and absorption structure for a fresh air fan, and belongs to the technical field of residence fresh air.The sound insulation and absorption structure comprises an outer layer and an inner layer.The outer layer is in a plane shape.The inner layer is fixedly connected to one side of the outer layer.The end, away from the outer layer, of the inner layer is of a wave structure.The trough positions of the wave structure are evenly provided with sound absorption hole structures.Each sound absorption structure comprises a spherical cavity located in the inner layer and located below the trough of the wave structure.The top end of each spherical cavity is provided with an opening communicated with the corresponding trough of the wave structure.Each sound absorption structure further comprises a cavity located below the corresponding spherical cavity and communicated with the corresponding spherical cavity.Each cavity is filled with a sound absorption material layer.The sound insulation and absorption structure ingrates sound insulation and absorption, can obviously reduce noise, and is high in practicability, simple in structure, smooth in outer surface and easy to machine.

The invention discloses a mute integrated cooker and a using method of a mute structure thereof. The mute integrated cooker comprises a gas stove, a range hood and a disinfection cabinet, a sound absorption cover is installed at a smoke suction port in the upper end of the range hood and completely covers the smoke suction port, and a sound absorption assembly is installed in the sound absorptioncover and comprises a sound absorption net rack plate and a sound absorption inner plate; and the sound absorption net rack plate is matched with a smoke suction net of the smoke suction port, and thesound absorption inner plate is installed on the inner wall of the sound absorption cover. According to the integrated cooker, the sound absorption cover is additionally arranged at the smoke suctionport of the integrated cooker, noise generated by flowing of oil smoke or collision of the oil smoke with the pipe wall in the smoke suction port is absorbed through the sound absorption cover, partof fan operation noise transmitted from a fan is absorbed, and therefore the purpose of sound absorption is achieved.

The invention discloses a preparation method of a photocatalytic magnesium cementing material, and a product thereof. The photocatalytic magnesium cementing material comprises the following components in parts by weight: 100 parts of magnesium oxide powder, 120-125 parts of a blender, 8-12 parts of a filler, 6-10 parts of natural fiber, 5-7 parts of perlite, 2.6-2.9 parts of titanium dioxide, 3-5 parts of a foaming agent and 0.5-32 parts of a photocatalyst. By adding the photocatalyst, the magnesium cementing material is endowed with environment purification and self-cleaning functions, a composite building material plate with new functions can be prepared, and good creativity is achieved. Besides, the preparation method of the photocatalytic magnesium cementing material is simple, and the prepared photocatalytic magnesium cementing material has the advantages of low energy consumption, thorough reaction, capability of realizing complete mineralization of organic matters, no secondary pollution, wide application range and very good development prospect and market value, and can be used for manufacturing floors, wallpaper and the like.

The invention relates to the field of sound absorption materials, in particular to a crystal composite fiber with a porous sound absorption structure and a preparation method thereof. A plurality of extremely small pores are formed in a crystal composite fiber body to form sound absorption gaps, sound waves penetrate into the pores of the material, the pores are mostly opening holes (sound absorption gaps) with communicated interiors, and the pores are subjected to friction and viscous resistance of air molecules and enable fine fibers to perform mechanical vibration, so that sound energy is converted into heat energy. The sound absorption coefficient of the porous sound absorption material is generally gradually increased from low frequency to high frequency, so that the sound absorptioneffect on sounds at high frequency and medium frequency is better. Polypropylene Z30S forms the resonance sound absorption structure of the crystal composite fiber, when the frequency of the sound waves is consistent with the natural vibration frequency of the resonance sound absorption structure, resonance occurs, and the sound waves excite the resonance sound absorption structure to vibrate andenable the amplitude to reach the maximum, so that the sound energy is consumed, and the purpose of sound absorption is achieved.

The invention discloses a submarine silencing damping material, and relates to the technical field of damping materials, the submarine silencing damping material comprises a silencing damping material, the silencing damping material is of a multi-layer structure, the silencing damping material comprises a damping material layer 1, an adhesive 1, a metal wire mesh, an adhesive 2 and a damping material layer 2, the first damping material layer is bonded with the metal wire mesh through a first adhesive, and the metal wire mesh is bonded with the damping layer through a second adhesive. Accordingto the submarine noise elimination damping material, the first damping material layer is arranged, the first damping material layer is composed of the high polymer and the inorganic filler, can be used for a free damping structure and a constraint damping structure, and has good damping performance, good flexibility and excellent flame retardant property, and the material has the characteristicsof oil stain resistance, seawater resistance, salt mist resistance, mold resistance, no toxicity and the like, physical tests show that the vibration acceleration level of a part treated by the material is reduced by more than 5dB, and the material is suitable for being used in a submarine cabin.

The invention discloses a building board with an excellent sound insulation effect. The building board with the excellent sound insulation effect comprises a composite board core body; a first heat conduction film is arranged on the outer surface of one side of the composite board core body; the composite board core body is fixedly connected with the first heat conduction film through UV glue; a second heat conduction film is arranged on the outer surface of the other side of the composite board core body; and the composite board core body is fixedly connected with the second heat conduction film through UV glue. According to the building board with the excellent sound insulation effect, through cooperation of a first porous sound absorption board, a second porous sound absorption board, afirst perforated sound absorption board, a second perforated sound absorption board and a solid board, sound waves can be weakened for multiple times; the sound insulation and noise reduction effectsare excellent; the first heat conduction film and the second heat conduction film both possess excellent heat conduction capacity, so that the heat radiation speed in the silencing process is increased; a first nanometer self-cleaning coating and a second nanometer self-cleaning coating have the self-cleaning characteristics, so that stains are difficult to attach; and a better use prospect is brought.

The invention relates to a composite noise reduction device. The composite noise reduction device can be fixed on a rigid wall. The composite noise reduction device includes a micro-perforated plate and a backing connected to the micro-perforated plate; a plurality of sound-absorbing micro-holes is arranged passing through the micro-perforated plate; the backing is provided with a plurality of sound-absorbing mechanisms corresponding to the positions of the sound-absorbing micro-holes to enhance the sound-absorbing performance; and the sound-absorbing mechanisms are penetrated on the backing.According to the application, the backing is further provided on the original micro-perforated plate, and the sound-absorbing mechanisms corresponding to the positions of the sound-absorbing micro-holes are provided on the backing; therefore, the sound-absorbing effect is further enhanced.

The invention discloses a sound absorption assembly for an anechoic chamber and the anechoic chamber. The sound absorption assembly for the anechoic chamber comprises a perforated outer frame and a plurality of layers of polyester fiber cotton; the perforated outer frame wraps the outer edges of the multiple layers of polyester fiber cotton; the densities of the multiple layers of polyester fiber cotton are different; the densities of the multiple layers of polyester fiber cotton are different; and the multiple layers of polyester fiber cotton are sequentially arranged along the thickness direction of the perforated outer frame. The polyester fiber cotton of different densities can absorb sound waves of different frequency bands, and based on the characteristic, the multiple layers of polyester fiber cotton of different densities are arranged in the perforated outer frame to achieve noise elimination of multi-frequency-band sound, and a sound absorption wedge does not need to be used in a matched mode. Therefore, the problems that a sound absorption structure used by an existing anechoic chamber still needs to be provided with a sound absorption wedge to achieve an anechoic chamber with the cut-off frequency below 100 Hz, only the length of the sound absorption wedge is reduced, and improvement and development need to be carried out are solved.

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.

The invention discloses a making method of an automobile sound-absorption carpet. The carpet is formed by pressing a layer A, a layer B, a layer C and a layer D from top to bottom at high temperature. The preparation method includes the steps that a, opening, mixing, carding, cross lapping, needling forming and raising shaping are performed on 100% fine Danny PET fibers to form the layer A having excellent sound-absorption performance; b, opening, mixing, carding, cross lapping and needling forming are performed on three-dimensional crimped fibers and L-PET fibers to form the layer B having a certain thickness and a certain tightness degree; c, a three-roll hot ironing machine is used for pasting the PE face of a PEPA asymmetrical film of the layer D to the layer B, and then cooling is performed to form PET bottom felt finally; d, a PE film is used for pasting the fabric of the layer A to the face, without the PEPA asymmetrical film, of the PET bottom felt formed in the step c, so that the automobile sound-absorption carpet is formed. The automobile sound-absorption carpet has the advantage that the fine Danny fibers are adopted for achieving the sound-absorption effect of the product according to requirements.