178results about How to "Improve frequency response characteristics" patented technology

A capacitive micromachined ultrasonic transducer (CMUT) includes a structured membrane which possesses improved frequency response characteristics. Some embodiments provide CMUTs which include a substrate, a first electrode, a second movable electrode, and a structured membrane. The movable second electrode is spaced apart from the first electrode and is coupled to the structured membrane. The structured membrane is shaped to possess a selected resonant frequency or an optimized frequency response. The structured membrane can include a plate and a beam coupled to the plate such that the resonant frequency of the structured membrane is greater than the resonant frequency of the plate. Furthermore, the ratio of the resonant frequency of the structured membrane over the mass of the structured membrane can be greater than the ratio of the resonant frequency of the plate over the mass of the plate. In some embodiments, the CMUT is an embedded spring ESCMUT.

The invention discloses a capacitive microphones chip, which relates to a microphone technology. The capacitive structure is that a vibration film is at the upper part and a back electrode is at the lower part. The vibration film is supported by a plane compound suspension girder or a vertical suspension girder so that the stress is distributed uniformly when the vibration film vibrates. The connection between the vibration film and the back electrode can be effectively reduced and the yield rate also can be improved; the suspension girder structure is soft and the vibration film has a good vibration characteristic. Only the center part of the back electrode is suspended and the surrounding part thereof is covered on a substrate. The supporting of the substrate increases the rigidity of the back electrode; a stiffener can be arranged on the suspension part of the back electrode; therefore, the rigidity of the back electrode can be further improved. The edge of the vibration film is provided with numerous small holes which can release an initial sacrificial layer between the vibration film and the back electrode coordinating with acoustic holes on the suspension part in the back electrode, as well as have an improvement effect to the acoustic characteristics of the microphones. The capacitive microphones chip has the characteristics of high sensitivity, low noise, and wide frequency band. The chip has a small volume. The manufacturing process is simple and batch production is easy to be carried out.

The invention relates to a frequency support control method used for a doubly-fed wind generation set and based on two-stage power tracking optimization. The invention starts from optimization of frequency support dynamic characteristics of a wind generation set and provides a frequency support control method used for the wind generation set and based on two-stage variable proportion coefficient optimized power tracking. On the basis, a variable proportion coefficient control strategy in an inertial response stage is derived based on a virtual inertia time coefficient and a rotor movement equation, and for quick recovery of a maximum power tracking operation mode of the wind generation set after inertial support and avoiding secondary disturbance from being produced on system frequency adjustment in a recovery process, a variable proportion coefficient control strategy in a maximum power tracking operation mode recovery stage is designed by adopting fussy control. The frequency supportcontrol method provided by the invention has control robustness, a control structure is simple, engineering implementation is easy, and the quick recovery of the maximum power tracking operation modeof the doubly-fed wind generation set after inertial response and inertial support on a power grid frequency can be realized.

The invention belongs to the technical field of holographic printing and three-dimensional display and particularly relates to a printing system of a holographic stereogram and with an abnormal-shaped mask plate. The printing system is formed by a laser light source, a beam splitter, an expanded beam collimation system, a spatial light modulator, a computer, a total reflection lens, a focusing lens, hologram recording materials, the abnormal-shaped mask plate, a target object and a CCD (Charge Coupled Device) camera. A transformation parallax image of the target object is obtained through the CCD camera and the computer and loaded into the spatial light modulator, a light beam which is emitted from the laser light source is modulated, interference is produced between the modulated light beam and the other laser beam which is reflected by the beam splitter, the two light beams penetrate the abnormal-shaped mask plate to be exposed and recorded on the holographic recording materials, and accordingly printout of the holographic stereogram of the target object is achieved. The printing system of the holographic stereogram and with the abnormal-shaped mask plate has the advantages of being capable of effectively improving the printout speed of the hologram, solving the problem of frequency spectrum leakage of the traditional hard edge aperture printing of the holographic stereogram due to the abnormal-shaped mask plate and improving the representing quality of the holographic stereogram.

The invention discloses a branch cantilever beam vibration generator which comprises a cantilever beam, a piezoelectric element that is arranged at the root of the cantilever beam and works in a drawing compression mold state, at least one branch arranged on the cantilever beam, and counter weights arranged at the end parts of the branches and the cantilever beam. According to the generator, the branches are integrated at different parts of the cantilever beam, so that the frequency domain response characteristic of the generator is improved; and only the single piezoelectric element is used, so that electric energy management is easy.

The invention discloses a seismic geophone tailstock used in the tail cone (1) at the end of a hood. Mei enclosures installed at the tail cone (1) detector at the junctions. Mei Mei hood is a spherical enclosures (2), tail cone surface cover (4) or Globoidal tail enclosures (5), referred to the end of the hood and tail cone (1) for a fixed link, or demolition activities-connected. Cone surface or rigid spherical or Globoidal use, the quality of light made of non-magnetic material or magnetic materials. The invention overcomes the traditional detector on a single tail cone fixed the shortcomings, overcome detector loose in the desert or placement on the land, coupled conditions caused by bad signal sensitivity decrease or signal distortion effects of increased detector grounding coupling area and stiffness can be decreased detectors caused long tail cone stacking effect, thereby enhancing the sensitivity of the detector; improved detector frequency characteristics, and to improve the detection of high-frequency signals in the detection of capacity.

The present invention invention belongs to the field of film material and film technology. The invented very small thermo-lag shape memory alloy film consists of two-element NiTi alloy with Ni 51.9-52.6 wt% and Ti 47.4-48.1 wt% and has a thickness of 5-8 microns. It is prepared through magnetically controlled sputtering and post-crystallizing process including the step of: selecting cast NiTi alloy as sputtering target; sputtering NiTi film and post-crystallizing treatment of the NiTi film. The present invention has typical R phase change characteristic at room temperature, and can take complete R phase change and inverse phase change. NiTi / Si driving film has characteristic frequency up to 400 Hz and obvious raised dynamic characteristic. The present invention raises the response frequency of the shape memory alloy.

The invention discloses an electrical power system transient overvoltage acquisition system. The system comprises a condenser bushing, a voltage transducer, a secondary resistance-capacitance divider, a transducer, an amplifier and a correcting circuit, wherein the condenser bushing, the voltage transducer, the secondary resistance-capacitance divider, the transducer, the amplifier and a liquid crystal display screen are sequentially connected, the correcting circuit is in output connection with the secondary resistance-capacitance divider, a voltage signal which is output by the voltage transducer is transmitted to the secondary resistance-capacitance divider, the correcting circuit comprises a voltage doubling circuit and a waveform adjusting circuit, correction of the system can be achieved, the system reliability is improved, a voltage dividing system is a condenser bushing end screen voltage dividing system, the frequency response characteristic is good, errors caused when measurement of impulse voltage is performed can be greatly reduced, and real-time acquisition and monitoring of internal and external overvoltage can be achieved.

The invention discloses an ultraviolet photodiode based on NiO / Ga2O3, comprising a top electrode and a bottom electrode, wherein A P-type crystal NiO film, an I-type crystal beta-Ga2O3 film, and an N-type single crystal beta-Ga2O3 substrate are sequentially disposed between the two electrodes from the top electrode to the bottom electrode. The invention also discloses a preparation method of an ultraviolet photodiode based on NiO / Ga2O3. The invention solves the problem that the Ga2O3-based pn junction ultraviolet photodiode cannot be prepared due to the lack of p-type Ga2O3 material in the prior art.

The present invention discloses a giant magnetostrictive micro displacement drive device based on the principle of temperature control by phase change water cooling. The current is used for controlling the drive device to output the displacement and through the coordination of the phase change temperature control device and the water cooling circulating device, the inside heat of the drive is brought to the outside environment to suppress the temperature increasing of the drive and heat output error to improve the control precision of the displacement output. The drive of the invention has the advantages of simple structure, relatively small drive current, stable operation and good frequency response, and combines the advantages of the phase change temperature technique and water cooling temperature control technique to perform long-time temperature control and suppress the heat output error effectively, without establishing a complex mathematical model. Consequently, the control precision of the displacement output can reach the micron grade or higher and the device can adapt to various poor working conditions. At the same time, the device has the advantages of small volume, light weight, large output force and highly precise displacement, can suppress the influence of the thermal deformation on the output displacement of the drive and can be used in the fields of ultraprecise machining and vibration control.

The invention belongs to the technical field of aircraft, and discloses a controller and control method for a magneto-rheological damper of a landing gear of an aircraft. A core control module is separately connected to a landing-gear position indication system and a flight management computer through data buses; an angle sensor feeds back the swing state of aircraft wheels; and a current sensor feeds back actual working electric currents of coils of the damper. The control method comprises the steps of determining, during the landing and taxiing of the aircraft, the operation state of the controller by virtue of a landing-gear deploying-and-retracting state acquired by the landing-gear position indication system and the flight altitude and flight state acquired by the flight management computer, calculating the working electric currents required for the coils of the magneto-rheological damper according to the swing state of the aircraft wheels acquired by the angle sensor and the aircraft speed, descent rate and load data acquired by the flight management computer, controlling a current driving module to output target currents, and controlling the output damping of the magneto-rheological damper. The controller and control method for the magneto-rheological damper of the landing gear of the aircraft can adjust the damping force of the magneto-rheological damper in real time according to the shimmy state of the landing gear, and effectively suppress the shimmy of the landing gear.

A high-precision adjustable electric control equalization circuit of a cable television network comprises one or more basic electric control equalization modules with an adjustable slope. The circuitalso comprises a control module and one or more compensation modules. The control module is electrically connected to the basic electric control equalization modules so as to control the slope changesof the basic electric control equalization modules. The control module is electrically connected to the compensation modules so as to generate a compensation signal according to the slope changes ofthe basic electric control equalization modules. The output of the basic electric control equalization modules is electrically connected to the input of the compensation modules so as to output a complete signal after the two are overlaid. The high-precision adjustable electric control equalization circuit of the cable television network can obtain good signal waveform flatness at each slope.

Reducing, suppressing or canceling parallel parasitic capacitance and / or resistive effects that affect the frequency response of components, elements and / or circuits in an electronic circuit or system that exhibit inductance is disclosed. Noise generated by parallel parasitic capacitance and / or parasitic resistance of the components, the physical orientation of the components, and / or the layout of components, devices and / or conductive tracks (board traces) on printed circuit boards within an electronic circuit or system is reduced, suppressed or canceled. The reduction, suppression or cancelation is achieved by adding a current source in parallel with a part or component of the electronic circuit or system that exhibits inductance, the current source being adapted to deliver a compensating current of roughly equal magnitude and roughly opposite phase to parasitic current associated with the part or component.

The invention discloses a double-screen frequency selective surface (FSS) capable of optimizing electromagnetic transmission characteristics, belongs to the field of microwave technology, and solves the technical problem that the passband property is extremely deteriorated when the double-screen frequency selective surface (FSS) is under large-angle irradiation in the prior art. The double-screen frequency selective surface comprises a first dielectric layer, a first adhesive layer, a first frequency selective surface layer, a second frequency selective surface layer, a fourth adhesive layer and a second dielectric layer arranged in sequence; the double-screen frequency selective surface also comprises a dielectric cylinder layer arranged between the first frequency selective surface layer and the second frequency selective surface layer; the dielectric cylinder layer comprises dielectric cylinders arranged periodically; and the two ends of the dielectric cylinders are fixed on patches in annular gap units of the first frequency selective surface layer and the second frequency selective surface layer respectively. When the double-screen frequency selective surface is under irradiation of TE 70 degrees, the passband and stop band can still keep the excellent frequency response characteristics; and in addition, the double-screen frequency selective surface is light in weight, simple in structure, low in cost and easy to process.

The invention discloses a giant magnetostrictive micro feeding drive device based on the principle of temperature control by gas cooling. The current is used for controlling the drive device to output the displacement and a gas-cooling temperature controlling device is used for suppressing the temperature increasing of the drive and heat output error to improve the control precision of the displacement output. The drive of the invention has the advantages of simple structure, relatively small drive current, stable operation and good frequency response. The forced air cooling is adopted to perform long-time temperature control and suppress the heat output error effectively. Furthermore, a belleville spring adds to the balance of the prestress, and a self-centering steel ball can maintain the output force at the shaft of the output mandril. Consequently, the control precision of the displacement output of the actuator can reach the micron grade or higher and can adapt to various poor working conditions. At the same time, the actuator has the advantages of small volume, light weight, large output force and highly precise displacement, can suppress the influence of the thermal deformation on the output displacement of the drive and can be used in the fields of ultra-precise machining and vibration control.

The invention discloses a signal protection filter circuit for an electronic mutual inductor. The signal protection filter circuit includes two signal input ends and two signal output ends. The two signal input ends and the two output signal output ends are connected to a protection circuit and a filter circuit therebetween. The protection circuit includes any one or any three combination of a gas discharge tube module, a pressure-sensitive resistance module and a transient inhibition diode module. The gas discharge tube module, the pressure-sensitive resistance module and the transient inhibition diode module are in coupled connection therebetween through a resistor or an inductor. The signal protection filter circuit inhibits overvoltage, overcurrent, common mode interference and differential mode interference. The signal protection filter circuit has simple structure, strong protection, excellent frequency response features and small influence on the precision of the electronic mutual inductor.

The invention discloses a CuAlO2 / Ga2O3 ultraviolet photodiode, comprising a top electrode and a bottom electrode, wherein a P-type crystal CuAlO2 film, an I-type beta-Ga2O3 film, and an N-type singlecrystal beta-Ga2O3 substrate are sequentially disposed between the two electrodes from the top electrode to the bottom electrode. The invention also discloses a preparation method of a CuAlO2 / Ga2O3 ultraviolet photoelectric diode. The invention solves the problem that the Ga2O3-based PIN ultraviolet photoelectric diode cannot be prepared due to the shortage of p-type Ga2O3 material in the prior art.

Embodiments of the present invention disclose a Residual Current Device (RCD). The RCD includes: a first zero-sequence current transformer, used for passively detecting a residual current signal of a current-carrying conductor; a first processing circuit connected to the first zero-sequence current transformer, used for acquiring the residual current signal from the first zero-sequence current transformer, and actively processing the residual current signal, where the first processing circuit is connected to a power source; a second zero-sequence current transformer, used for actively detecting the residual current signal appearing on the current-carrying conductor; and a second processing circuit connected to the second zero-sequence current transformer, used for acquiring the residual current signal from the second zero-sequence current transformer, and actively processing the residual current signal, where the second processing circuit is connected to the power source. The RCD can make a very good response within a wide frequency range, and achieve better frequency response characteristics.

The invention discloses an omnidirectional magnetic concentrator type lamb wave electromagnetic acoustic transducer, wherein the transducer comprises a cylindrical neodymium-iron-boron magnet, a magnetic concentrator and a circular array type back-folding line ring. The multi-cluster circular zigzag line ring in a flexible circuit board is placed on the surface of an aluminum plate to be detected,and the magnetic concentrator and the neodymium-iron-boron magnet are attracted and then placed right above a return line ring. Based on lorentz force effect, the stimulating of omni-directional S0 modal guided wave in a plate structure is realized. Experiments verify that the prepared array type omnidirectional magnetic concentrator type lamb wave electromagnetic acoustic transducer can be usedfor stimulating a single S0 mode guided wave in the aluminum plate; with an omni-directional test experiment carried out, the developed omnidirectional magnetic concentrator type lamb wave electromagnetic acoustic transducer can stimulate to a S0 guide wave spread in the 360-degree direction; and a defect detection experiment verifies that the omnidirectional magnetic concentrator type lamb wave electromagnetic acoustic transducer can effectively reduce the analysis difficulties and errors of defect signals.

The invention discloses servo loop feedback control technology in a resonant optical gyroscope. The resonant optical gyroscope comprises an optical system composed of a tunable laser, an optical splitter, three frequency shifters, two modulators, an optical resonant cavity, and a photoelectric conversion module; and a processing circuit composed of a modulation / demodulation module, and three feedback locking modules. The invention relates to control technology where a P (proportion) module forms a fast small-amplitude frequency feedback while an I (integrator) or PI module forms a slow large-amplitude frequency feedback, adopts a high-order integrator I<n> (n is an integer greater than or equal to 2) or PI<n> to track the temperature change caused resonant frequency linear drift problem and suppress low frequency noise, and connects the P, I and I<n> in parallel to form a resonant frequency servo loop, to therefore reduce the resonant frequency drift caused by rapid laser frequency fluctuation and ambient temperature in the loop, and improve frequency locking precision and system frequency response characteristics.

A electro-magnetic microphone with double magnetic circuits, including a housing unit, two magnetic units, and one responding unit; wherein the housing unit includes two holes formed one two sides of the diaphragm; the magnetic unit is arranged in the housing unit and disposed one by one in one axis, wherein each magnetic unit includes a magnet generating multiple geomagnetic line, and one heel piece embracing the magnet and provides the mentioned geomagnetic lines; the response unit is provided with diaphragm disposed upward along the axis and between magnetic units, and a coil covering the diaphragm; thus, the inventive electro-magnetic microphone with double magnetic circuits has frequency response characteristic in both high and low frequency without use of bias power supply.

The invention provides a wind storage combined power station participation frequency modulation optimization control method, system and device and a medium. During primary frequency modulation, rotor kinetic energy is controlled and released through fan virtual inertia so as to damp frequency drop in an inertia response stage; the defect of later output reduction of the fan is overcome through energy storage, the problem of secondary frequency drop caused by the fan is avoided, and the frequency response characteristic of the system in the primary frequency modulation stage is effectively improved; during secondary frequency modulation, a fan power variable quantity reference value and an energy storage power variable quantity reference value are determined by taking the minimum cost of a frequency modulation power supply participating in automatic power generation control as a target, and secondary frequency modulation control is performed based on the fan power variable quantity reference value and the energy storage power variable quantity reference value. And the energy storage service life can be prolonged, and meanwhile, the dynamic frequency characteristic of the system can be improved.

The invention discloses a laminated metallic film capacitor which comprises an insulating base plate. A metallic film electrode and a metallic film electrode are arranged on the insulating base plate; a medium film for completely separating the metallic film electrode from the metallic film electrode is arranged between the metallic film electrode and the metallic film electrode; the metallic film electrode, the metallic film electrode and the medium film form a laminated structure; the metallic film electrode is provided with an extraction electrode; the metallic film electrode is provided with an extraction electrode; and a passivating protective layer is arranged outside the laminated structure. The laminated metallic film capacitor adopts a film made of material such as tantalum pentoxide and the like which is insulating and has good chemical stability to be taken as a dielectric medium so as to solve the problems that a dielectric medium of a general film capacitor has low dielectric constant, poor heat resistance, poor film forming performance and low mechanical strength, and the like. In addition, due to masking process, two metallic films are deposited as the electrodes, so that the metal using amount is greatly reduced, the production cost is lowered, and the producing process is simple.

The invention provides an acoustic-electro conversion chip of a silk-ribbon microphone, which is made by a semiconductor process technology and a micro electro mechanical technology. The acoustic-electro conversion chip comprises a supporting frame layer and a response unit layer which is arranged on a supporting frame and is used for transforming acoustic energy into an induced electromotive force which can be output for application, wherein the response unit is provided with an insulating diaphragm layer and a voice coil film which is arranged on the diaphragm and can be conductive; the diaphragm comprises a vibration area which can deform under the action of the acoustic energy and a fixed area which is connected to the supporting frame; and the voice coil film comprises two voice coils which are wound in the same direction in a rectangular shape from inside to outside, and each voice coil comprises a plurality of first vertical sections which are vertical to a field direction and positioned in the vibration area and can generate the induced electromotive force by displacement. By virtue of the design, the sensibility of the voice coil film can be increased, and the frequency response characteristics of the silk-ribbon microphone can be effectively enhanced.

The invention discloses a T-type network device for calibrating a monopole antenna for electromagnetic compatibility measurement. The T-type network device comprises a shielding box body, wherein a stepped structure is arranged in the shielding box body, a T-type network circuit board is fixedly arranged on the stepped structure, a signal source interface, a spectrometer interface and a tested antenna interface are arranged in the T-type network circuit board, a shielding box top cover is fixedly arranged on the top of the shielding box body, the front side face and the back side face of the shielding box body are respectively and fixedly provided with a coaxial SMA contact, an insulation isolation support is fixedly arranged on the left side face of the shielding box body, an opening is formed in the insulation isolation support, and the connecting end of an antenna base connector penetrates through the opening of the insulation isolation support to be electrically connected with the T-type network circuit board; one of the SMA contacts is electrically connected with the signal source interface, and the other of the SMA contacts is electrically connected with the spectrometer interface; the connecting end of the antenna base connector is electrically connected with the tested antenna interface.

The present invention discloses a single film capacitance type microphone chip, which relates to a microphone technology, the present invention is a single film capacitance type microphone, a capacitance structure is formed by utilizing a single film and a base seat. A vibrating diaphragm is connected with the upper surface of a cantilever beam support through the cantilever beam frame of the cantilever beam, forming a three-dimensional vibrating structure that the cantilever beam and the vibrating diaphragm is not at the same level; the cantilever beam is flexible, the vibrating diaphragm is rigid, the distortion is mainly concentrated on the cantilever beam when the vibrating diaphragm vibrates, the vibrating diaphragm basically keeps a translational movement; a plurality of apertures are arranged on the edge of the vibrating diaphragm to improve a frequency response property, a corrosion hole is arranged simultaneously; in addition, a shock-proof back stop is manufactured on the chip. The present invention has the advantages that the sensitivity is high, the noise is low, the property is wide frequency band, the volume of the chip is small, the manufacture process is simple, and the volume production is easy.

The present invention discloses a resonant single phase unidirectional transducer type surface acoustic wave acceleration sensor. The sensor comprises two groups of oscillators having sensitivity foracceleration signals respectively arranged at a middle portion and a tail end of an upper surface of a cantilever beam, the oscillator located at the tail end is taken as a reference, the two groups of the oscillators form a differential structure to facilitate reducing of influences of a temperature and a transverse acceleration; structure parameters of the two groups of the oscillators are identical, output ends of the oscillators are connected, and the two groups of the oscillators are subjected to frequency mixing through a mixer to convert change of external acceleration to change of frequency for output; and each of the two groups of the oscillators comprises one surface acoustic wave delay line and one feedback amplifier, and each surface acoustic wave delay line employs one resonant single phase unidirectional transducer (RSPUDT) with Gaussian function frequency response, wherein each RSPUDT comprises one input transducer and one output transducer. The resonant single phase unidirectional transducer type surface acoustic wave acceleration sensor is good in frequency response characteristic, high in stability, high in sensitivity, good in linearity, low in insertion loss andhigh in anti-noise interference capability, and is suitable for application demands in the fields of automobiles, steamships, trains, etc.

The invention discloses a rock-soil mass direct-shear test apparatus capable of quickly and accurately compressing. The rock-soil mass direct-shear test apparatus comprises a platform and a default sliding rail arranged in the middle of the platform, wherein the default sliding rail comprises a long side; a lower shear box is arranged at the upper part of the default sliding rail; the lower shear box slides along the long side of the default sliding rail; an upper shear box is arranged at the upper part of the lower shear box; a rigid transfer rod is arranged in the normal direction of the upper shear box; the rigid transfer rod is fixedly connected with a normal compression system; the normal compression system transfers default stress generated by the normal compression system to the normal direction of the upper shear box through the rigid transfer rod; one side of the lower shear box is connected with a tangential compression system; the other side of the lower shear box is connected with a displacement measurement system and a pull pressure measurement system. The rock-soil mass direct-shear test apparatus can quickly and accurately compress, the direct-shear test efficiency and accuracy are improved and the rock-soil mass direct-shear test apparatus is suitable for research on various rock-soil mass shear properties.