77 results about "Noise reduction coefficient" patented technology

The invention discloses a sound-absorbing coating material, wherein every 100 parts by mass of coating contains 5-50 parts by mass of sound-absorbing function materials, 0.1-35 parts by mass of flame retardant materials, 10-40 parts by mass of binding materials, and the balance of an inorganic filling, an assistant and water in a common coating. The sound-absorbing function materials are selected from one or composite of some of materials such as slag fibers, mineral fibers, glass fibers and wood fibers, with fiber structures, and the sound-absorbing function materials are subjected to waterproof modification treatment. According to the invention, NRC (Noise Reduction Coefficient) of the coating material is tested to be more than 0.4 by using a standing wave tube method, and the sound-absorbing coating material has a good sound-absorbing denoising performance, excellent flame resistance and low heat conductivity coefficient, can be used for reducing the energy consumption of a building, is an environmental-friendly functional sound-absorbing coating material integrated with functions of sound absorption, flame resistance and decoration, and can be used on the surface of the building.

The invention provides a three-dimensional porous framework-reinforced fiber sponge containing high-efficiency sound-absorbing material and preparation thereof. The three-dimensional porous framework-reinforced fiber sponge containing high-efficiency sound-absorbing material is characterized by comprising three-dimensional porous framework-reinforced fiber sponge and a microporous membrane compounded on the three-dimensional porous framework-reinforced fiber sponge. The sound-absorbing material is the high-efficiency sound-absorbing material obtained by introducing a three-dimensional porous framework with certain mechanical strength as a main body supporting reinforcing structure, putting the three-dimensional porous framework into flame retardant-containing fiber slurry, forming the slurry, drying a solvent, curing to obtain the reinforced fiber sponge with a reinforcing framework therein, and compounding the reinforced fiber sponge with the microporous membrane. The noise reduction coefficient (NRC) of the obtained sound-absorbing material is 0.34-0.59; and the sound-absorbing material shows relatively high sound-absorbing performance.

A moldable composite sheet having improved adhesion characteristics, particularly at elevated service temperatures, as well as improved sound absorption and attenuation of transmitted sound intensities. In one aspect, the composite sheet may be a porous fiber-reinforced thermoplastic comprising discontinuous reinforcing fibers and having an adhesive skin layer covering. Generally, the-composite sheet may have a void content or porosity from about 5% to about 95% by volume of the sheet, an areal weight between about 400 g/m² to about 4000 g/m² and a fiber content from about 20% to about 98% by weight. The composite sheet can be molded via low pressure processes, such as thermoforming, match metal molding on stops, vacuum forming and pressure forming, to produce durable automotive interior trim parts capable of withstanding service temperatures exceeding 100° C. for extended periods of time along with improved sound absorption capabilities exceeding a noise reduction coefficient (NRC) rating of 0.5.

The invention discloses a honeycomb sound-absorbing panel and a production process thereof, which comprises a three-layer structure, the middle layer is a hexagonal honeycomb core, the upper surface of the hexagonal honeycomb core is provided with a supporting sheet; The invention fills the hexagonal honeycomb cavity with sound-absorbing materials such as filling the hexagonal honeycomb cavity, and the sound wave passes through the microporous aluminum plate and is absorbed by the sound-absorbing material in the hexagonal honeycomb core to achieve the sound-absorbing effect, and can be used for sound-absorbing ceilings and walls in public places. Such as the ceilings and walls of airport waiting halls, stadiums, conference halls and other places, the noise reduction coefficient is high, which can reach more than 0.8, and it can be used as a large-area wide-slab ceiling. It is beautiful, light in weight and no deformation.

Polymer foams having a good balance of high sound absorption, low thermal conductivity and generally low water absorption are disclosed which are obtainable by perforating (i.e., hole punching) a polymer foam having a moderately large cell size (1.5 mm to 4 mm) and an open content not greater than 40 percent to increase the open cell content of the foam by at least about 10 percent relative to the non-perforated foam, the polymer foam matrix preferably made of a thermoplastic foam, such as a low-density polyethylene (LDPE) resin, a high melt strength (HMS) polypropylene resin (PP), or a blend of an HMS PP resin and an LDPE resin, optionally containing a cell size enlarging agent such as glycerol monostearate, an antioxidant, carbon black and/or flame retardant additives, using a volatile organic compound, e.g. isobutane, as blowing agent. These foams are useful for applications in which a combination of acoustic absorption, thermal insulation and possibly low water absorption is needed, such as outdoor, motor vehicle and marine applications. They exhibit a noise reduction coefficient greater than 0.3, a thermal conductivity not greater than 90 mW/m° K measured at an average temperature of 10° C. according to DIM52616 and a low (less than 10, such as less than 1.5, percent by volume) water absorption when measured according to EN 12088 at a 50° C. temperature gradient for an exposure test period of 14 days.

Accepting the speech having the noise superimposed thereon and converting it into a signal on a time axis of the speech, an amplitude component of a speech for each predetermined frequency band of the converted signal on the frequency axis is calculated. Calculating a noise reduction coefficient, the noise component is reduced by multiplying the signal on the frequency axis of the original signal by the calculated noise reduction coefficient. By estimating the target value of the remaining noise for each frequency band, a signal on a frequency axis in which a signal corresponding to a frequency band of which target value estimated by the noise target value is larger than the value of the amplitude component of the signal on the frequency axis of which noise component is reduced is corrected to a signal corresponding to the target value is restored, into a signal on a time axis.

In a conventional device for extracting voice features accurately without being influenced by noises, such as a voice recognition device, usually an input voice signal is processed first by a noise reduction system having the tap length N, and the result is FFT-processed by L-points, and then the power spectrum vector is calculated; accordingly, a one time operation requires N multiplications and (N-1) summations. The voice feature extraction device according to the invention receives a voice signal including noises from a microphone, which is processed by a window function operation unit, and thereafter FFT-processed by an FFT operation unit by L-points. A power calculation unit calculates a power spectrum vector of the input voice signal. However, a noise reduction system determines in advance a filter coefficient of this system and processes the coefficient to calculate a noise reduction coefficient, and the power spectrum vector is processed by this noise reduction system. Thereby, the voice feature extraction device of the invention reduces the processing volume to 1/(4N-2) in comparison to the conventional device, lightens the processing load of the processing unit, and increases the processing speed.

The present invention discloses an image blocking adaptive recursion noise reduction method. The method comprises: uniformly dividing a current image and the noise reduction result of a preview frame into a plurality of subblocks, performing motion detection of each subblock, and obtaining the motion parameter of each subblock; combining adjacent subblocks belonging to motion blocks into one motion region; calculating the noise reduction coefficient k of the preview frame and next frames through the image collection frequency parameters and the distance parameters and the motion parameters m of the subblocks and the motion region; and obtaining the noise reduction result of an nth frame image x(n) according to the noise reduction coefficient and a recursion noise reduction formula obtained through calculation. The present invention further discloses an image blocking adaptive recursion noise reduction device. Noise reduction parameters are adaptively regulated according to the noise level, the motion condition and the frame frequency of each block after doing difference and a distance between the current block and the motion region to effectively eliminate the motion trailing phenomenon and reduce the noise difference between blocks while the noise reduction effect in a stationary region is not decreased.

The invention relates to a solid waste foam concrete and a preparation method thereof, belongs to the technical field of engineering materials, and provides a preparation method for a noise reductionfoam concrete. According to a cementitious material, solid waste material steel slag, slag powder and desulfurized gypsum are firstly adopted as main components, and though double synergy optimizationbetween of particle size and the activity of the steel slag, slag and desulfurized gypsum without adding cement clinker or alkali-activator, the absorption of a large proportion of industrial solid waste is achieved. The preparation method for the foam concrete can save the milling time, reduce the energy consumption and improve the production efficiency by adopting a step mixing grinding technology mixing the ball mill and the segment mill; pores in the concrete can be further communicated by adopting high-temperature wet curing, while high compressive strength is kept, a high noise reduction coefficient is obtained, so that the noise reduction coefficient NRC exceeds 0.6, and the compressive strength can reach 10MPa, the concrete can be used as a wall sound absorbing structural materialin a noise reduction project, and the problems that traditional foam concretes are not high in strength, and the pores are not communicated are solved.

The invention provides compound modified asphalt concrete which is characterized by being prepared from the following raw materials in parts by weight: 100 parts of mineral aggregate, 3-7 parts of asphalt, 0.05-0.15 part of chlorinated polyethylene, 0.2-1.5 parts of aliphatic polyurethane resin, 0.075-1 part of serpentine, 0.15-1.5 parts of halloysite and 0.001-0.04 part of a coupling agent. The compound modified asphalt concrete provided by the invention is remarkably improved in noise reduction coefficient, has excellent pavement performance, is simple in preparation technology, has non-poisonous and harmless raw materials and has great social benefits for improving the pavement performance of asphalt and protecting the environment.

The invention discloses a sound barrier unit board based on a wide band microperforated panel sound absorber, and belongs to the technical field of environmental noise control. The sound barrier unit board comprises the sound absorber and a sound insulation backboard. The sound absorber comprises a microperforated panel and cavity sets with different depths. The sound insulation backboard comprises a back panel, an upper side panel and a lower side panel, and the left side and the right side of the sound insulation backboard are sealed with end sealing plates. The cavity sets with different depths are arranged on the back panel of the sound insulation backboard, and the opening sides of the cavity sets with different depths face the microperforated panel. The invention further discloses a designing method of the sound barrier unit board. The sound barrier unit board has the advantages of environment friendliness, simple structure, high strength, high weather resistance and the like. The noise reduction coefficient of the sound absorption unit board is not lower than 0.8. The sound barrier unit board has an excellent sound absorption property in a highway noise energy concentration frequency band, 1/3 octave center frequency random incidence sound absorption coefficients in the range from 125 Hz to 2500 Hz are all higher than 0.5, and the average value of 1/3 octave center frequency random incidence sound absorption coefficients in the range from 160 Hz to 2000 Hz is 0.85; and meanwhile the weight-counted sound insulation quantity Rw reaches 31 dB.

The invention relates to an audio signal processing method and device, terminal equipment and a storage medium. The method comprises the following steps: acquiring original noise signals acquired by at least two audio signal channels; distinguishing a noise signal frame and a voice signal frame in a time domain according to the at least two original noisy signals, wherein the voice signal frame comprises a voice signal and a noise signal which are superposed in a time domain; the noise signal frame comprises noise generated when the voice signal is silent; determining the power of the voice signal and the power of the noise signal according to the noise signal frame and the voice signal frame; determining a noise reduction coefficient according to the power of the voice signal and the power of the noise signal; and based on the noise reduction coefficient, performing noise reduction on the original noise signals.

The invention provides a sound absorption and insulation sheet material and a preparation method thereof. The sound absorption and insulation sheet material is composed of, by weight, 50 to 80 parts of cement, 20 to 30 parts of pottery sand, 30 to 40 parts of waste haycite, 6 to 10 parts of silica sol, 5 to 8 parts of starch, 3 to 5 parts of a water repellent, 1 to 8 parts of carbon fiber, 1 to 3 parts of a foaming agent, and 7 to 15 parts of water. The preparation method is simple; operation is convenient; rive sand can be replaced with pottery sand; broken stone can be replaced with waste haycite; a large amount of solid waste in urban garbage can be used; the preparation method is beneficial for changing wastes into valuables, realizing resource cyclic utilization, reducing mineral mining and consumption, and protecting the environment; and the obtained sound absorption and insulation sheet material is high in noise reduction coefficient, and possesses excellent thermal insulation properties.

The invention discloses a cement-based sawdust composite noise barrier mainly applicable to noise preventing projects of railways and urban light railway projects. The cement-based sawdust composite noise barrier comprises a sawdust layer and a concrete layer. The sawdust layer is made by mixing sawdust particles, glue, cement, water and yellow sands according to a weight proportion of 1:0.048-0.052:1.8-2.2:4.5-5.5:2.7-3.3. Bonding force of cement gum is used to bond the sawdust layer and the concrete layer. Pores of the sawdust layer are used to absorb noise energy for consumption, and accordingly noise reduction is achieved, noise reduction coefficient reaches more than 0.7, and noise insulation factor reaches 25dB. The cement-based sawdust composite noise barrier is fine in noise absorption, fracture-resistant, high in impact strength, fine in freezing and thawing resistance, stable in material chemical properties, humidity-resistant, anticorrosion, mildew-resistant, nonflammable, pollution-free, easy to transport, convenient to mount and maintain and the like.

The invention discloses a polymeric microparticle acoustic panel. The polymeric microparticle acoustic panel comprises raw materials in percentage by mass as follows: 89%-98.5% of aggregate, 1.4%-10.7% of an adhesive, 0.003%-0.03% of graphene and 0.003%-0.3% of silane. According to a preparation method, the adhesive, graphene and silane are mixed, sufficiently stirred for 5-10 min, ultrasonicallyirradiated and stirred for 5-30 min, and then the aggregate is added and stirred uniformly, and a mixture is obtained; a layer of mixture is laid in a mold, gridding cloth is added, the mold is fullypaved, pressing molding is performed, and the graphene reinforced polymeric microparticle acoustic panel is obtained. A graphene sheet layer in the polymeric microparticle acoustic panel is stably dispersed in the adhesive, oxygen-containing functional groups on graphene or graphene oxide participate in a curing reaction of the adhesive, and strength of the polymeric microparticle acoustic panel is improved; by reasonable selection of the adhesive quantity, strength of the acoustic panel is guaranteed, the polymeric microparticle acoustic panel contains a large quantity of communicated micropores inside, NRC (noise reduction coefficient) of the polymeric microparticle acoustic panel is guaranteed, and sound absorbing effect of the polymeric microparticle acoustic panel is improved.

The invention relates to a wedge-shaped perlite resonance acoustical tile, which is mainly made of expanded perlite and cement and is characterized in that the surface of the acoustical tile, which faces the incident direction of acoustic waves, is wedge-shaped; and a closed air resonance cavity is constructed inside the acoustical tile. The acoustic absorption coefficient of the wedge-shaped perlite resonance acoustical tile disclosed by the invention is greater than 0.75 in the frequency range of 125-5000Hz, the noise reduction coefficient of the wedge-shaped perlite resonance acoustical tile reaches 0.93, and the wedge-shaped perlite resonance acoustical tile can be used for manufacturing high-efficiency acoustical barrier of railways and roads.