690results about How to "Improve the attenuation effect" patented technology

The invention relates to the field of products of sound insulation material, solves the problems in the prior art that the sound insulation material is poor in sound insulation effect, is incomprehensive in high and low frequency sound insulation, causes pollution and is easy to age, and provides an efficient sound insulation material and a manufacturing method thereof. The efficient sound insulation material includes a sound insulation layer, a sound absorption layer, and a bubble layer, wherein the bubble layer is located between the sound insulation layer and the sound absorption layer. The sound absorption layer is made of a sound insulation compound, and the sound insulation compound is prepared by raw materials of the following substances: a thermoplastic resin, inorganic fillers, and a foaming agent, wherein the inorganic fillers account for 15-80wt%, the foaming agent accounts for 5-15wt%, and the rest is the thermoplastic resin. In the efficient sound insulation material, the fillers with different particle diameters correspond to sound waves of different wave bands or frequencies, and thus consumption of sound energy of different frequencies is relatively comprehensive, and the sound insulation effect is good, so the sound insulation material is suitable for popularization and application.

An internal duct of an aircraft engine pod may include a fan and a tubular air intake having a first acoustic attenuation internal tubular piece. The first acoustic attenuation internal tubular piece is acoustically homogeneous, is of the resonator type, and has no internal assembly fish-plate. Additionally, the internal duct may include a tubular fan casing and a tubular transition part for connecting the air intake to the fan casing. An internal face of the tubular transition part is acoustically homogeneous also. Moreover, the internal face of the first acoustic attenuation internal tubular piece and the internal face of the tubular transition part are disposed in aerodynamic continuity.

A plurality of spatially located ultrasound beacons are provided in known locations within a distributed communications system. Each of the ultrasound beacons is configured to emit ultrasound pulses that can be received by client devices in ultrasound communication range of the ultrasound beacons. The client devices are configured to analyze the received ultrasound pulses from the beacons to determine their time-difference of arrival and as a result, their location in the distributed communications systems. Use of ultrasound pulses can provide greater resolution in location determination of client devices since ultrasound waves experience strong attenuation in building walls, ceilings, and floors, thus avoiding detection of ultrasound waves from other ultrasound beacons not located in proximity to the client devices.

The invention discloses a solar cell with a composite dielectric passivation layer structure and a preparation process thereof. A silicon oxide film, an alumina film and a silicon nitride or silicon oxynitride film are deposited in turn on the front, back and sides of a p-type silicon substrate to form a composite dielectric film on the whole surface, and windows are opened locally to lead electrodes out. Through aluminum oxide, silicon dioxide, silicon oxynitride, silicon nitride with different refractive indexes and a back surface passivation layer with a laminated structure of the materials, the back surface recombination rate is greatly reduced, the back reflectivity is improved, the CTM of a module is reduced, and the light attenuation and heat-assisted light attenuation and the anti-PID performance of the cell are improved. The structure can be made on a boron/gallium-doped p-type monocrystalline silicon, p-type polycrystalline silicon or p-type monocrystalline-silicon-like substrate, and a passivation method based on the composite dielectric film passivation structure can be used to manufacture PERC cells, double-sided PERC+ cells and imbricate PERC cells. Based on the preparation process steps and sequence, the corresponding preparation mode and the process parameter range of the laminated structure, the making of the cell can be well completed.

The invention provides a three degree of freedom micro-vibration suppression platform and a control method thereof, belongs to vibration isolation and suppression devices, and solves problems of complicated structure and complex control method of a prior active-passive composite vibration isolation structure. The platform provided by the invention includes a base platform, a load platform, three sets of single degree of freedom active-passive composite vibration isolation assemblies which are totally identical and a controller. The upper end and the lower end of each single degree of freedom active-passive composite vibration isolation assembly are connected with the load platform and the base platform. The control method provided by the invention includes calculating logic axis translation signals, calculating logic axis control signals, calculating physical axis real time control signals and transmission steps. The platform provided by the invention is simple in structure, adjustable in rigidity, is capable of suppressing and isolating three degree of freedom microvibration in rotation directions of an X axis and a Y axis and a translation direction of a Z axis and is suitable for different occasions. Microvibration of different frequency bands can be dampened effectively and reliable guarantee can be provided for precision machining and measurement equipment in a microvibration environment.

The invention provides a method for achieving speech enhancement, which comprises the following steps: performing frame separation and pre-emphasis processing on a noisy speech signal, and transforming the noisy speech signal into a frequency domain; dividing the noisy speech signal into a plurality of frequency bands, calculating the signal energy of each frequency channel, and updating the estimated value of the noise energy; calculating the posteriori signal-to-noise ratio of the current frame, and the estimated value of the priori signal-to-noise ratio; calculating the attenuation factor of each frequency band, and processing the attenuation factor to obtain a speech signal with increased signal-to-noise ratio; and transforming the speech signal after the processing into a time domain, and outputting the speech signal.

A six-degree-of-freedom micro vibration suppression platform includes a basic platform, a load platform, six sets of single-degree-of-freedom active and passive composite vibration isolation devices that are exactly the same and a controller. Upper and lower ends of each set of single-degree-of-freedom active and passive composite vibration isolation devices are connected with the load platform and the basic platform, respectively. A control method includes: calculating a logical axis signal, calculating a logical axis control signal, calculating physical axis real-time control signals and a transfer step.

The invention provides a method for driving a pixel and a driving circuit of the pixel. The method comprises the following steps of: charging the first end and the second end of a first capacitor according to a reference voltage and a reset voltage respectively, and simultaneously switching on a third switch; floating the second end of the first capacitor; charging the first end of the first capacitor according to a data voltage, and switching off the third switch; and floating the first end of the first capacitor, and switching on the third switch. Therefore, a driving current irrelevant with the variation of an N-type thin film transistor process and the span voltage of an organic light-emitting diode can be determined by the voltage difference between the first end and the second end of the first capacitor.

The invention provides a solid defoaming agent. The solid defoaming agent consists of the following components in percentage by weight: 50 to 90 percent of carrier, 5 to 20 percent of defoaming active matter, 0.5 to 4 percent of emulsifier, 1 to 30 percent of structural agent and 5 to 15 percent of water. A method for preparing the solid defoaming agent comprises the following steps of: (1) adding the defoaming active matter, the emulsifier and the structural agent into a mixer and fully mixing the components so as to obtain a mixture A; (2) adding an organic carrier into the mixture A and uniformly stirring so as to obtain a mixture B; (3) adding deionized water into the mixture B and uniformly stirring so as to obtain a mixture C; and (4) pelletizing the mixture C by using a pelletizer and drying the obtained particles by using a drier so as to obtain the solid defoaming agent. The solid defoaming agent has high defoaming and foam restraining performance and anti-damping performance, and can be applied to industries such as daily use chemicals, industrial cleaning and the like.

The coupling (10) comprises a body (16) suitable for being fitted onto a tube (12) in leaktight manner, and a locking clip (22) that is elastically deformable between a locking configuration in which at least one locking zone (24A, 24B) of the clip can catch on a catch surface (14) of the tube and an unlocking configuration. The clip (22) is disposed over the wall of the body (16), which wall is provided with at least one transverse slot (30A, 30B) through which the locking zone (24A, 24B) projects into the body when the clip is in the locking configuration, and with at least one setback (32A, 32B; 36A, 36B) provided at the end of the slot, a portion of the bottom of said setback forming an unlocking ramp (34A, 34B; 38A, 38B) on which an unlocking zone (35A, 35B; 37A, 37B) can slide in order to cause the clip to go from its locking configuration to its unlocking configuration. The width of the unlocking zone is greater than the width of the locking zone and than the width of the slot, but less than or equal to the width of the setback, said widths being measured axially.

The invention relates to aqueous radiation-resistant coating belonging to the chemical engineering technology field. The aqueous radiation-resistant coating takes flaky graphite powder, acetylene carbon power, carbonyl iron powder and ferrite power as main materials with electromagnetic wave absorption function and takes diffusant, cement, film forming agent, ammonia and pure water as auxiliary materials. The aqueous radiation-resistant coating has the electromagnetic wave absorption frequency of 1.0-20000 MHz, can attenuate the electromagnetic wave absorption by 2-20 dB according to the different coating thickness, can solve the unsolvable problem of purifying environment polluted with electromagnetic radiation by shielding material and effectively prevent the harm of electromagnetic radiation to surrounding equipment and personnel.

The invention relates to a preparation method for polydopamine-coated polyethyleneimine-stablized gold-nanometer-star photothermal treatment agent. The preparation method comprises the following steps: preparing a gold seed solution from chloroauric acid and sodium citrate; activating mercaptoacetic acid with EDC, then adding an aqueous PEI solution and carrying out a reaction, dialysis, cooling and drying so as to obtain PEI-SH; adding dopamine hydrochloride into a Tris buffer so as to obtain dopamine Tris buffer; adding the gold seed solution into a chloroauric acid solution, adding a AgNO3 solution and an ascorbic acid solution under stirring, adding PEI-SH after stirring reaction and carrying out a reaction so as to obtain AuNSs-PEI; and adding AuNSs-PEI into the dopamine Tris buffer and carrying out stirring and centrifugation so as to obtain the photothermal treatment agent. The preparation method has the advantages of simplicity, mild reaction conditions, easy operation and industrialization prospects; and the prepared star-like nanometer agent has application potential in the fields of CT imaging diagnosis and photothermal treatment of cancers.

The invention discloses a shearlet transform and fast bilateral filter image denoising method, comprising the following steps: 1) using a noise imaging system to collect the envelope signal of a noise image, and establishing a medical ultrasonic image model; 2) performing the step 1 ) The medical ultrasound image model obtained after the logarithmic transformation utilizes a pyramid filter bank to perform multi-scale and multi-directional decomposition, 3) the two-dimensional discrete shearlet transformation coefficient of the high-frequency part in each sub-band image obtained in the step 2) Carry out threshold method contraction processing; 4) Utilize fast bilateral filter to carry out filter processing to the shearlet coefficient of step 2) middle and low frequency part; 5) Perform shearlet inverse transformation processing to all coefficients after step 3) and step 4) processing, obtain Noised medical ultrasound images. The introduction of the fast bilateral filter in the present invention can not only improve the denoising performance but also greatly improve the processing efficiency.

The invention discloses radiation-proof rubber protective gloves. The gloves comprise the following components in percentage by weight: 29 to 56 percent of rubber latex, 0.1 to 0.5 percent of sulfur, 0.1 to 2.5 percent of zinc oxide, 0.2 to 0.5 percent of rubber accelerator, 0.3 to 0.5 percent of rubber antioxidant and 40 to 70 percent of radiation-proof material. In the gloves, when the beam energy is 60KVp, the attenuation rate is over 45 percent; when the beam energy is 80KVp, the attenuation rate is over 35 percent; when the beam energy is 100KVp, the attenuation rate is over 26 percent; when the beam energy is 120KVp, the attenuation rate is over 22 percent; and the gloves have very good attenuation effect on X-rays and have good protection effect. The gloves have good mechanical property, the tension at break is more than 16N, the elongation at break is over 750 percent, and the gloves meet the requirement of Disposable Sterilized Rubber Surgical Gloves of GB7543-2006 and have high practical value.

The invention relates to a low-attenuation bending insensitive single mode fiber which comprises a core layer and wrapping layers. The low-attenuation bending insensitive single mode fiber is characterized in that the relative refractive index difference delta1 of the core layer ranges from 0.30% to 0.38%, the radius R1 of the core layer ranges from 3.5 micrometers to 4.5 micrometers, the four wrapping layers are arranged outside the core layer, the first wrapping layer is a first inner wrapping layer tightly surrounding the core layer, the relative refractive index difference delta2 of the first wrapping layer ranges from -0.02% to 0.02%, the radius R2 of the first wrapping layer ranges from 6.5 micrometers to 8.5 micrometers, the second wrapping layer is a second inner wrapping layer tightly surrounding the first inner wrapping layer, the relative refractive index difference delta3 of the second wrapping layer ranges from -0.02% to 0.02%, the radius R3 of the second wrapping layer ranges from 8 micrometers to 11 micrometers, the third wrapping layer is a downwards-concave wrapping layer tightly surrounding the second inner wrapping layer, the relative refractive index difference delta4 of the third wrapping layer ranges from -0.5% to -0.2%, the radius R4 of the third wrapping layer ranges from 12 micrometers to 20 micrometers, and the fourth wrapping layer is an outer wrapping layer tightly surrounding the downwards-concave wrapping layer and is a pure quartz glass layer. The low-attenuation bending insensitive single mode fiber can be completely matched with a G.652.D optical fiber, and therefore the low attenuation, the large effective area and the bending resistance can be better unified.

The new LED back light module includes LED units on a base plate, one casing and one light scattering and refracting mechanism with outer vertical plane as the outgoing plane. It features the partially reflecting and partially transmitting optical structure unit set in the light outgoing direction of the LED units and with structure independently to the LED units. The light from the LED' s is transmitted partially and scattered mostly in the optical structure unit so as to avoid LED shade spot in the light outgoing plane of the module. The optical structure unit may be regulated flexibly to reach proper ratio between the transmitted light and the scattered light. The present invention is suitable for various kinds of LED light source.

A blade for a turbomachine extends in use, in a radial direction relative to the axis of the turbomachine. The turbomachine has at least one operating condition which generates supersonic fluid flow at the blade. The blade is adapted to provide, at the supersonic operating condition, a leading edge sweep angle which varies such that successive radial positions (i) to (iii) along the leading edge are at respective sweep angle turning points. Position (i) is the radially inner and position (iii) the radially outer of the positions. Position (i) is at or radially outward of the 30% span position, where 0% span is the radially innermost point of the leading edge and 100% span is the radially outermost point of the leading edge.

A muffler for internal combustion engines, in order to achieve a high attenuating effect without reducing the attenuating effect in the high revolution range of the engine, comprising one or more expanding chambers 11 through 13 formed in a muffler 1, an inlet pipe 5 which opens into a expanding chamber 11 and introduces exhaust gas into the muffler 1, and an outlet pipe 6 which opens into other expanding chamber 13 and introduces exhaust gas out of the muffler 1. In the muffler, the exhaust gas discharged through an aperture 5a of this inlet pipe 5 is inverted once or more times in the muffler 1 and is introduced into an aperture 6a of the outlet pipe 6. In a contraflow area L2 in which the flowing direction C of exhaust gas flowing in the expanding chambers 11 through 13 and the flowing direction E of exhaust gas flowing in the outlet pipe 6 are not the same, interference holes 7 composing of a plurality of small holes communicating with the expanding chambers 11 through 13 are bored in the outlet pipe 6. The aperture area of the small holes 7 is kept at not less than 1% but not more than 5% of the surface area of the outlet pipe in the contraflow area L2.

The invention discloses a piezoelectric active vibration isolating mechanism which comprises a first force sensor, a spring corrugated pipe, an intermediate mass block, a first flexible hinge, a piezoelectric actuator, a second force sensor, a second flexible hinge and a controller. One end of the first force sensor is connected with a base platform, and the other end of the first force sensor is sequentially connected with the second force sensor, the spring corrugated pipe, the intermediate mass block, the second flexible hinge, the piezoelectric actuator and the first flexible hinge. The first force sensor and the second force sensor are respectively used for detecting the vibrating signals of the base platform and the vibrating signals of a load platform and can respectively transmit the detecting vibrating signals to the controller, and the controller can control the piezoelectric actuator to exert acting force on the load platform to compensate the load platform. By means of a two-stage serial-connection suspending structure, the inherent frequency of the structure is effectively reduced, and micro-vibration low-frequency interference in precision equipment can be effectively restrained.

The invention discloses an MXene-based flexible polyvinyl alcohol electromagnetic shielding composite film and a preparation method thereof, and belongs to the technical field of electromagnetic shielding materials. The invention relates to an MXene-based flexible polyvinyl alcohol electromagnetic shielding composite film and a preparation method thereof. The preparation method comprises the following steps of: etching an MAX phase with hydrofluoric acid to obtain layered MXene, then intercalating the MXene and graphene to obtain an MXene/Graphene compound, loading magnetic nanoparticles Fe3O4 on the MXene/Graphene to obtain a Fe3O4@MXene/Graphene ternary composite material, and finally dissolving the Fe3O4@MXene/Graphene ternary composite material and polyvinyl alcohol in deionized water and drying to obtain the polyvinyl alcohol composite film. The obtained polyvinyl alcohol film has very good flexibility and has good compatibility with a composite filler, and the electromagnetic shielding effectiveness in the X wave band can reach 38-52 dB. Layered MXene and graphene with good conductivity are beneficial to multi-reflection attenuation of electromagnetic waves, the impedance matching characteristic is optimized through combination with the magnetic particles Fe3O4, and attenuation of the electromagnetic waves is facilitated.

A decorative, lightweight panel structure that is adaptable for use as interior ceiling panels, interior wall panels, and exterior sheathing or siding, which exhibits excellent rigidity, and which can be made to exhibit a combination of good sound attenuation property, excellent aesthetic appearance, uniformity of aesthetic quality, outstanding weatherability, and/or low manufacturing cost, includes a non-woven fibrous batt comprised of thermoplastic fibers, a scrim layer bonded to each of two opposite sides of the non-woven fibrous batt, and a decorative film layer having a surface indicia on an exterior side and an opposite interior side bonded to one of the scrim layers.