78results about How to "Achieve noise" patented technology

The invention discloses a high-linearity broadband stacking low noise amplifier based on a gain compensation technology. The high-linearity broadband stacking low noise amplifier comprises a two-stacking low noise amplification network, an interstage matching network and a two-stacking gain expansion amplification network which are connected in sequence; and a first power supply bias network and a second power supply bias network which are connected with the two-stacking low noise amplification network and the two-stacking gain expansion amplification network. According to the high-linearity broadband stacking low noise amplifier, a serial stacking structure is realized through adoption of two transistors with different sizes and ultra wide band noise and impedance matching are realized through combination of an RLC feedback network; through utilization of the gain compression compensation technology, the gain compression property of the two-stacking low noise amplification network is cancelled within a certain bias range through the two-stacking gain expansion amplification network and a linearity index of the amplifier is improved, so the whole low noise amplifier has good broadband, linearity, low power consumption and low noise amplification capability; and moreover, the low breakdown voltage property of an integrated circuit technology is avoided and the stability and reliability of a circuit are improved.

The invention provides a gas sensor based on TMDCs-SFOI heterojunction and a preparation method thereof. The gas sensor takes two-dimensional transition metal sulfide TMDCs as a gas sensitive layer and a semiconductor film on an insulator SFOI as a conductive channel; after TMDCs are contacted with SFOI, due to the Fermi level difference, electrons are transferred from the high Fermi level side tothe low Fermi level side, thereby generating space charge regions on both sides of the heterojunction and forming a p-n junction; when gas molecules to be detected are adsorbed on the surface of theTMDCs and charge transfer occurs between the gas molecules to be detected and the TMDCs, the concentration of carriers in the TMDCs is changed, a p-n junction potential barrier is changed, the width of the space charge region in the SFOI is changed, and finally the resistance of the conductive channel is changed, so that the gas to be detected is sensed. According to the gas sensor based on TMDCs-SFOI heterojunction and the preparation method thereof, the gas sensitive layer is separated from the conductive channel, meanwhile, the high sensitivity of the two-dimensional TMDCs to adsorbed gas molecules is utilized, and a gas detector is beneficial to achieving high sensitivity and high reliability and can be directly integrated on a semiconductor chip together with the mature traditional semiconductor device process.

A circuit for preventing corrosion of a contact, includes an input terminal, a signal line, a switch, an impedance element, and a comparator. The input terminal is to be connected to the contact, which is outside the circuit. The signal line is connected to the input terminal. The switch is connected to the signal line. The impedance element is connected to the signal line in parallel to the switch. An impedance of the switching section is smaller than that of the impedance element. The comparator compares a potential of the signal line with a predetermined potential. The switch is turned on based on a comparison result output from the comparator.

The invention discloses an image enhancement method, apparatus and device, and a storage medium. The method comprises the steps of obtaining an original image to be subjected to image enhancement; for each pixel point in the original image, determining a contrast gain coefficient and a floating correction coefficient corresponding to the pixel point according to a plurality of pixel values in a preset pixel area taking the pixel point as a center; reducing or increasing the contrast gain coefficient corresponding to the pixel point by using the floating correction coefficient based on the corresponding texture condition of the pixel point in the original image to obtain a corrected target contrast gain coefficient; according to the method, each pixel point in the original image is enhanced based on the target contrast gain coefficient, the enhanced target image is acquired, and contrast enhancement or suppression is performed in a targeted manner according to the corresponding texture condition of the pixel point in the original image, so that the image looks clearer and more natural.

The invention discloses an EMD (empirical mode decomposition) based computation method for recognizing sensitivity of a signal source. The computation method comprises main steps as follows: vibration signals under the normal oil supply parameter and under the adjusted oil supply parameter are set, and a correlation coefficient between the vibration signal under the adjusted oil supply parameter and an IMF (intrinsic mode function) component of the vibration signal is computed; a correlation coefficient between the IMF component and the vibration signal under the normal oil supply parameter is computed; a correlation coefficient difference value generated through oil supply parameter change is computed; the correlation coefficient difference value is subjected to standard processing according to the function, and a sensitivity factor is defined; a sensitive IMF component is selected according to the factor; the sensitive IMF component is subjected to wavelet time-frequency analysis, so that a diesel engine vibration source corresponding to the component is determined. With the adoption of the method, the diesel engine vibration source closely related with the oil supply parameter change is revealed, the recognition precision of the vibration source closely related with the diesel engine oil supply parameter change can be improved, and reasonable selection of the diesel engine oil supply parameter and vibration noise control are realized.

The invention discloses a method for controlling air-conditioning unit noise reduction. Whether partial load running is conducted on an air-conditioning unit or not is judged, if yes, a current noisevalue of a compressor and a current noise value of an outer draught fan are obtained, whether the difference value of the two noise values is within a set difference value range or not is judged, if yes, the air-conditioning unit continues to run according to a current state, and if no, the average value of the current noise value of the compressor and the current noise value of the outer draughtfan serves as a target noise value and the rotating speed of the compressor and the rotating speed of the outer draught fan are adjusted; and then whether the air-conditioning unit reaches a target output capability or not is judged, if no, the rotating speed of the compressor and the rotating speed of the outer draught fan are adjusted according to the target output capability till the air-conditioning unit reaches the target output capability, if yes, the current noise value of the compressor and the current noise value of the outer draught fan are obtained again, and whether the differencevalue of the current noise value of the compressor and the current noise value of the outer draught fan is within a set range or not is judged again. Thus, optimization of noise of an outdoor unit isachieved under the premise that the air-conditioning unit reaches the target output capability.

The invention discloses an exhausting spill-proof noise-reducing cup cover and a high speed blender. The cup cover comprises a cup body, a cup cover body is arranged at an open end of the upper portion of the cup body, a feeding cover is arranged in the cup cover body, a first annular cavity and a second annular cavity which are used for noise reduction and exhaust and communicated with each otherare combined between the inner side of the cup cover body and the outer side of the feeding cover, the first annular cavity is communicated with the feeding cover through an inner exhaust hole, and the second annular cavity in communicated with the outside through a second exhaust passage capable of preventing spill and breaking bubbles; and the high speed blender comprises the cup cover body. The exhausting spill-proof noise-reducing cup cover and the high speed blender have the advantages that noise can be prevented from directly being transmitted to the outside of the cup cover through aninner cavity, the first annular cavity and the second annular cavity, and noise in a wider frequency range can be eliminated; steam is discharged through the feeding cover and gathered by rapid condensation to become condensate water when passing through multi-ply and roundabout exhaust passage; sprays and bubbles can be quickly condensed and broken after passing through the multi-ply and roundabout exhaust passage, being squeezed by the sudden change of the exhaust passage and rubbing the side wall of the exhaust passage, and thereby being eliminated.

The invention discloses a range extender starting control method, a range extender and an electric vehicle and relates to the technical field of electric vehicles. After controlling a power generatorto pull an engine to rotate at a pulling torque, a range extender controller adjusts the pulling torque of the power generator according to an engine rotation speed obtained in real time till the engine is started. In the range extender starting process, the torque of the power generator is controlled on the basis of the range extender controller, different pulling torques are given for differentengine rotation speeds so that the pulling torque of the power generator to the engine is reduced with the increasing of the engine rotation speed to realize smooth starting of the engine; and therefore, shaking and noises caused by large rotation speed change in the starting process are avoided, the NVH performance of the electric vehicle is improved, and the prolonging of the service life of theengine is significant.

A mute electronic expansion valve comprises a valve shell, a valve rod, a valve rod supporting seat and a valve rod driving mechanism. The valve rod driving mechanism comprises a coil, a magnetic steel sleeve and a nut sleeve. A valve deck is sleeved with the coil which corresponds to the magnetic steel sleeve and can drive the magnetic steel sleeve to drive the nut sleeve to rotate. The valve rod supporting seat is sequentially divided into a nut sleeve motion supporting part and an installing supporting part in the axial direction. The valve rod is arranged in a central through hole of the valve rod supporting seat in a penetrating mode. The nut sleeve motion supporting part stretches into an inner cavity of the valve deck and is provided with a thread. Rotation and screw-thread fit of the nut sleeve drive the valve rod to move axially. An inner medium temporary storage cavity and an outer medium temporary storage cavity are formed between the installing supporting part and a valve seat, and at least one deflector hole penetrating through the inner medium temporary storage cavity and the outer medium temporary storage cavity is formed. After a medium is input through an input port, the medium is subjected to temporary storage and division of the outer medium temporary storage cavity, temporary storage of the inner medium temporary storage cavity and diameter change of the deflector holes, so that flow direction change, slowing and stabilizing of the medium are achieved, and the mute effect is achieved.

The invention discloses a volute molded line generation method which comprises the following steps: 1) determining at least three positioning points with characteristic meaning of a circle center, wherein the characteristic meaning is volute throat gap positioning, volute height or volute width; 2) taking the circle center as the original point, and determining a volute molded line in a curve fitting way according to coordinates of each positioning point; 3) after determining each positioning point, reversely deducing a coefficient m of Archimedes or log spiral, and fitting a curve graph withrespect to m-Phi by a smooth curve through an m value corresponding to each positioning point, wherein Phi is an included angle formed by the point and a starting radial section of the volute; 4) calculating to obtain values under different values through an Archimedes or log spiral formula: FORMULA, thereby obtaining a corresponding corrected volute molded line. The invention further discloses avolute generated by the method, a fan system applying the volute, and an extractor hood applying the fan system.

The invention belongs to the field of a spaceflight servo motor loading test and specifically discloses an inertia load simulation apparatus. The apparatus comprises a first shaft coupling, a torque sensor, an acceleration transducer, a second shaft coupling, an electric slip ring and a loading motor, wherein the output end of the first shaft coupling is connected with the input shaft of the torque sensor, the output shaft of the torque sensor is connected with one end of the second shaft coupling, the second shaft coupling is internally provided with the accelerated speed sensor, and the other end of the second shaft coupling is connected with one end of the electric slip ring. Inertia simulation of the apparatus is simple and is easy to operate, the acceleration measurement is accurate and highly reliable, and the apparatus has the advantages of noise isolation function, compact structural layout and integrated design.

The invention discloses a two-stage interception type scrap isolation type motor shaft polishing machine based on an intermediary principle. The machine is composed of a segmentation type water curtain intervention noise weakening protection unit, an interaction type cooling and collecting integrated unit, a polishing rotation auxiliary unit, a motor shaft limiting unit, a motor shaft containing frame, a polishing supporting vertical plate, a bottom moving platform, a motor shaft supporting crank arm, a collecting auxiliary vertical plate, moving wheels and a motor shaft collecting supporting base. The invention belongs to the technical field of motor shaft machining machinery, and particularly relates to a two-stage interception type scrap isolation type motor shaft polishing machine based on an intermediary principle. Under the condition that no scrap collecting equipment or cooling equipment or other related sensors are involved, the interaction type cooling and collecting integrated unit is arranged, the cooling function on a motor shaft is creatively achieved, meanwhile, residual scraps attached to the motor shaft are removed and collected, and the technical problem difficult to solve that in the prior art, the motor shaft is driven to move underwater is solved.

The invention provides a denoising cup cover and a wall breaker and belongs to the field of food processing equipment. The denoising cup cover comprises a feeding cover and a cup cover body, a silencing device is arranged on the feeding cover and comprises an inner barrel, an outer barrel, a middle barrel and first and second silencing cavities, and the first and second silencing cavities are surrounded by the inner barrel, the outer barrel and the middle barrel. When the wall breaker works, noise is reflected, enters the denoising device in the feeding cover along with steam flow, sequentially goes through the inner barrel, the first silencing cavity, a silencing hole, the second silencing cavity and a second through hole and is finally transmitted to the outside. The noise is reflected and interfered for several times in the process of transmission, attenuation of energy and noise level of medium-and-high-frequency noise is realized; low-frequency noise is weakened through sudden change of noise impedance caused by multiple times of contraction and expansion. In addition, water vapor generated in a cup body during food material steaming is condensed into water after going througha silencing structure of the feeding cover, condensed water and the lower end of the middle barrel form water sealing, and the noise is transmitted out through the silencing hole, so that denoising effect is improved further.

The invention provides an oscillating structure and a fan assembly or an electric heater assembly comprising the same. The oscillating structure comprises a base (1) and a rotary plate (2). When the base (1) and the rotary plate (2) are assembled, the axial lead of the axis of the base (1) coincides with the axial lead of the axis of the rotary plate (2); the axis of the rotary plate (2) is supported by the axis of the base (1); and supporting parts are arranged on the parts, in two or more positions on the radial outer sides/side of the axes/axis, of the rotary plate (2) and/or the base (1) and used for supporting the rotary plate (2) on the base (1). By arranging the supporting parts at the axis and in two or more positions on the radial outer side of the axis, a plane can be determined through the three or more supporting points jointly, and the effect that the rotary plate is stably supported on the base can be ensured; and the situation that the oscillating structure shakes during operation is avoided, and the oscillating structure operates stably and smoothly in the working and operation process.

The invention provides a marine electric field sensor test system and method, and belongs to the technical field of marine electric field sensor test. Multi-index test can be performed. The test system comprises a signal generator, a test box, a test circuit and a data acquisition recording subsystem, the test box comprises an outer box and an inner box, a constant-temperature water bath is arranged between the outer box and the inner box, and the inner box is filled with saline water and is provided with a conductive plate; the test circuit comprises a first acquisition end and a second acquisition end, the first acquisition end is connected with a first electrode of a to-be-tested sensor, a second electrode of the to-be-tested sensor is connected with a first single-pole double-throw switch, the second acquisition end is connected with a second single-pole double-throw switch, one wiring ends of the two single-pole double-throw switches are correspondingly connected, and a first resistor is connected between the other wiring ends; a second resistor is connected between the second single-pole double-throw switch and the first acquisition end; and the data acquisition recording subsystem comprises a data acquisition module connected between the first acquisition end and the second acquisition end, and further comprises a main control module and a monitoring module.

A reflecting-mirror-equipped lamp 100 including a high pressure discharge lamp 10 and a reflecting mirror 20. An opening 24 of the reflecting mirror 20 is provided with a front glass 22 and two air holes (31 and 32) are formed through the reflecting mirror 20. The air holes (31 and 32) are provided on a cross section (44) including a luminous bulb 11. If the cross section 44 is divided into regions (I through IV) consisting of first, second, third and fourth quadrants with respect to the luminous bulb 11, the air holes (31 and 32) are respectively provided in two quadrants diagonal to each other, i.e., in the first and third quadrants, respectively, or in the second and fourth quadrants, respectively.

The invention discloses a multi-level cyclone pipe type engineering machinery air filter. The number of filter levels is determined by the air intake volume and the air intake efficiency of an engineering machinery engine. Each level of filter is composed of a framework and a filtering material, wherein the porosity of the filtering material is reduced layer by layer from inside to outside, so that filtering layer by layer from large particles to small particles is achieved; the filtering material is composed of a base payer, a resistance layer and a surface layer, and achieves dissipation of energy under broadband random vibration and impact vibration. In order to reduce air intake noise, an air inlet is connected with a silencer. The air inlet of the filter adopts Y-shaped pipelines, the distance between the pipelines is adjusted in a self-adaptive mode according to noise caused by the airflow velocity of an air outlet pipe of the silencer, and therefore control over large-flow high-speed air filtered noise is achieved for the engineering machinery engine.