473 results about "Electromechanical coupling" patented technology

An ultrasonic probe is provided with a CMUT chip having a plurality of transducer elements that change electromechanical coupling coefficients or sensitivities in accordance with a bias voltage to transmit and receive ultrasonic waves, an electric conducting layer formed on the ultrasonic irradiation side of the CMUT chip, an acoustic lens arranged on the ultrasonic irradiation side of the CMUT chip, an insulating layer formed in the direction opposite to the ultrasonic irradiation side of the acoustic lens, a housing unit that stores the CMUT chip in which the electric conducting layer and the insulating layer are fixed with an adhesive and the acoustic lens, wherein the insulating layer is formed by the material that includes at least either silicon oxide or paraxylene to prevent a solvent of the adhesive from soaking into the adhered portion.

A vibrator of a beam type linear ultrasonic motor using bending vibration modes belongs to the technical field of piezoelectric ultrasonic motors and is used for the piezoelectric ultrasonic motors. The vibrator solves the problem that the mechanical output capabilities of the ultrasonic motors are restricted because of low tensile strength and low electromechanical coupling efficiency of ceramic materials in the prior art. The vibrator comprises two driving pads, two end covers, two insulating sleeves, two pairs of piezoelectric ceramics with polarization directions being thickness directions, a flange, two thin-walled beams and mounting bases; wherein, studs extend out from the end faces of the flange along the axis of the flange; each stud is sleeved with a pair of piezoelectric ceramics; an end cover is screwed at the overhanging end of each stud; the tail end of each end cover is provided with a driving pad; each piezoelectric ceramic is composed of two symmetrical half piezoelectric ceramics which are combined after being split; the polarization directions of the two half piezoelectric ceramics are opposite; the splitting lines of the two pairs of piezoelectric ceramics at both sides of the flange are vertical to each other; the polarization directions of the piezoelectric ceramics in each pair are opposite.

The invention discloses a two-planet-row electromechanical coupling driving device of a hybrid vehicle in the technical field of machinery. The device is provided with a front planet row and a back planet row; each of the two planet rows is provided with a planet wheel, a sun gear and a row gear ring; the two planet row gear rings are connected with each other by a clutch. An engine is connected with the planet wheel of the front planet row; an ISG motor is connected with the sun gear of the front planet row; the gear ring of the front planet row is connected with the driving disk of the clutch; the driven disk of the clutch is connected with the gear ring of the back planet row; the planet carrier of the planet wheel of the back planet row is arranged fixedly on a car frame; the sun gear of the back planet row is connected with a drive motor; the outside gear of the gear ring of the back planet row is normally engaged with a power take-off gear. The two-planet-row electromechanical coupling driving device of the hybrid vehicle has the advantages of compact structure, large transmission ratio, large load support capability, stable driving, and high transmission efficiency, thereby realizing power dividing and infinite variable speed at the same time.

The invention discloses an interfacial debonding monitoring method for a steel tube concrete tube wall based on piezoelectric impedance measurement, which comprises the following steps of: sticking piezoceramics sheets as self-driving automatic sensors on the surface of a steel tube of a steel tube concrete member; applying alternating current voltage on the piezoceramics sheets to obtain the ratio of input voltage signals with different frequencies to output current, namely the impedance of an electromechanical coupling system; transmitting an acquired electromechanical coupling impedance signal to an analytic terminal of a computer by using a GPIB (General-Purpose Interface Bus) data bus; selecting an electromechanical coupling impedance measurement result of piezoceramics at the debonding damage-free position of the steel tube concrete member as a reference value; and defining a damage index and calculating the magnitude of the damage index corresponding to each piezoceramics sheet to obtain the bonding condition of the steel tube wall at the positions where the piezoceramic sheets of the steel tube concrete member are arranged and a concrete interface. According to the interfacial debonding monitoring method disclosed by the invention, the position and the range of the interfacial debonding damage, which cannot be directly observed by naked eyes, in the steel tube concrete member can be accurately and quickly found out; and the interfacial debonding monitoring method has the advantages of high sensitivity, simpleness and convenience in operation and low price.

The invention discloses a method for predicting influence of vibration deformation on electric performance of an array antenna. The method comprises the following steps of: 1) determining a geometric model file of the array antenna; 2) establishing a finite element model of the array antenna in ANSYS; 3) presetting an acceleration power spectrum, calculating random vibration deformation, and extracting position offset of each radiation unit; 4) calculating a pattern function of the array antenna; and 5) judging whether the pattern function satisfies design requirements. According to the conventional method, whether the structure strength of the antenna satisfies the requirement is analyzed according to the acceleration power spectrum, and the electrical performance cannot be determined according to array plane deformation errors. The method provided by the invention can realize the prediction on the electrical performance of the antenna according to the offset caused by random vibration; the method provided by the invention is more succinct, can introduce the offset into an electromechanical coupling model to calculate the electrical performance, and does not need to repeat electromagnetic modeling according to the change of the offset; and the method provided by the invention is used for analyzing the influence of vibration on the antenna and finding main structural factors, thereby ensuring that the antenna is protected from being damaged, and the electrical performance of the antenna in a working state is improved.

An inexpensive compact band rejection filter realizes a high sharpness of a filter characteristic at ends of passbands and has a large attenuation. In the band rejection filter, at least one of a plurality of elastic wave resonators, which contributes to formation of a transition band, has a propagation angle larger than those of the other elastic wave resonators. Accordingly, the at least one of the plurality of elastic wave resonators which contributes to the formation of the transition band has an electromechanical coupling coefficient that is smaller than electromechanical coupling coefficients of the other elastic wave resonators.

According to an exemplary embodiment, a bulk acoustic wave (BAW) resonator includes a piezoelectric layer having a disrupted texture region, where the disrupted texture region is situated in a controlled thickness region of the BAW resonator. The BAW resonator further includes lower and upper electrodes situated on opposite surfaces of the piezoelectric layer. The controlled thickness region has controlled electromechanical coupling and includes a segment of material situated over the upper electrode. The segment of material can be a metal or a dielectric material. The disrupted texture region can be situated at an edge of the BAW resonator and can extend along a perimeter of the BAW resonator.

The invention relates to a titanium acid barium based piezoelectric ceramic material which uses titanium dioxide and barium carbonate as initial raw materials to produce tetragonal barium carbonate based powder through milling and pre-sintering solid phase reaction. The particle average size of the powder is at submicron grade, and the crystal structure of the powder is tetragonal. Then the titanium acid barium based piezoelectric ceramic material is produced, which is provided with a microstructure, the average size of the middle grain particle diameter of which is 0.2-7.5 Mu m, and the piezoelectric performance index d33 value of which is larger than 225pC/N. the barium titanate based piezoelectric ceramic material of the invention has the characteristics of low production cost, large piezoelectric constant d33 value and high planar electromechanical coupling factor kp value, can be applied to various electronic components and devices of sensors, drivers, ultrasonic transducers, resonators, filters, buzzers, electronic igniters, etc. and can be used as lead-free piezoelectric ceramic to substitute lead bearing PZT piezoelectric ceramic material which is widely applied currently.

The invention discloses a method for preparing film bulk acoustic wave resonator on the basis of a monocrystal AlN. The method comprises the following steps of: growing (111) an oriented monocrystal Al film on a preparation substrate by using a molecular beam epitaxial growth method; growing (002) an oriented monocrystal AlN film on the oriented monocrystal Al film by using a pulse laser deposition growth method; and depositing a layer of metallic film on the AlN film to form a Al/AlN/metal sandwich piezoelectric stack structure. The piezoelectric stack structure based on monocrystal AlN prepared by the method can be used for preparing the film bulk acoustic wave resonator. The piezoelectric performance of the monocrystal AlN film is superior to that of a polycrystal AlN piezoelectric film applied to film bulk acoustic wave resonator so that the quality factor and a valid electromechanical coupling factor of a device are increased.

The invention discloses a sodium bismuth titanate based lead-free piezoelectric ceramic and a preparation process thereof. The general formula of the piezoelectric ceramic composition is (1-x)(Na0.5Bi0.5)1-aMaTiO3-xNaNbO3, wherein, x is the mol content of NaNbO3 in a ceramic system, a is the atom number of composite ions (Na0.5Bi0.5) which are replaced by M in (Na0.5Bi0.5)TiO3, x is not less than 0 but less than 0.3, a is more than 0 but less than 0.3, and M represents divalent alkaline earth metal elements Ba, Sr and Ca. As a secondary isostatic pressing forming method is adopted in the preparation process, the piezoelectric ceramic has the advantages of simple operation, high stability and low cost; and the method helps easily obtain high-density microcrystal ceramic materials, obviously improve the piezoelectric parameter and electromechanical coupling factor of the materials, and meet the practical requirement of the piezoelectric ceramic materials used in a micro-displacement actuator.

The invention discloses a shaped surface-oriented quick determination method for adjustment quantity of an active panel of a large parabolic antenna. The method comprises the steps of determining an antenna structure model and an actuator supporting node; determining an overall reflection surface shape of the large parabolic antenna under two working modes, and determining a fitting equation of a shaped surface; extracting node information of the active panel on the refection surface; calculating a target curved surface with minimum fitting root mean square error with the shaped surface; determining corresponding nodes of the panel and the target curved surface, and calculating an actuator adjustment quantity; calculating axial errors of all nodes of the adjusted overall reflection surface; calculating an antenna gain using an electromechanical coupling, judging whether the antenna gain meets the requirement, and outputting an optimal actuator adjustment quantity. By adopting the method, the optimal adjustment quantity of the active panel actuator of the antenna can be directly and accurately adjusted, so that the adjusted overall reflection surface of the antenna is closer to the shaped surface, the electric performance of the antenna can be obviously improved, and an accurate surface shape conversion function of the large parabolic antenna under two working modes is realized.

The invention discloses a modeling method for the dual-driving synchronous electromechanical coupling characteristic of a walking beam type gantry machine tool and solves the problems that the mechanical characteristics of a coupling part of the walking beam type gantry machine tool are decoupled and modeled. The modeling method is characterized in that the factor that the load of the gantry machine tool moves on a cross beam is considered and the problems that the speed of the dual-driving two-shaft coupling part is decoupled with force can be solved. According to the modeling method disclosed by the invention, the actual conditions of the mechanical characteristics for the dual-driving two shafts during synchronous movement can be accurately reflected and main factors for influencing the asynchronous error of two shafts can be disclosed; and the modeling method provides theoretical basis for measures for reducing the dual-driving asynchronous error.

The invention discloses an electromechanical coupling-based direction adjustment method of a large-scale forming double-reflection surface antenna. The method includes the following steps that: (1) the finite element model of an antenna structure is established; (2) the piecewise fitting surface of the forming main reflection surface of the antenna is determined; (3) finite element node coordinates after the thermal deformation of the main reflection surface, as well as the rotation angle and vertex displacement quantity of an auxiliary reflection surface are calculated; (4) the optimal matching surface of the forming main reflection surface of the antenna after deformation is determined; (5) antenna direction deviation caused by temperature distribution of the main reflection surface of the antenna is calculated; (6) direction deviation of the auxiliary reflection surface caused by the thermal deformation of the antenna is calculated; (7) total direction deviation caused by the structural thermal deformation of the antenna is calculated; (8) the total direction deviation of the antenna under a local coordinate system is converted into direction adjustment quantity of the antenna under a geodetic coordinate system; and (9) the direction of the antenna and the direction of beams after adjustment are calculated. According to the method of the invention, the electric performance of the antenna is improved through adjusting the azimuth pitch angle of an antenna servo system. The analysis and calculation processes of the method are more concise and efficient.

The invention discloses a method for predicting electrical properties of deformed log-periodic antennae based on an electromechanical coupling model, aiming to mainly solve the problem of electromechanical separation in the log-periodic antennae. The method comprises the following steps: building a finite element model based on the structural design parameters of the log-periodic antennae, loading dead load, random wind and other environmental loads and carrying out finite element analysis to obtain the structure displacement field of the log-periodic antennae; utilizing the analysis results to obtain current distribution of oscillator units in the log-periodic antennae and phase difference caused by the positions and deflection of the oscillator units and computing the far field patternsof the log-periodic antennae according to the superposition theorem; and obtaining the electrical property parameters of the log-periodic antennae to realize electromechanical coupling analysis of the log-periodic antennae. The method can help the log-periodic antenna structural design personnel improve the antenna design and manufacturing quality.

The invention relates to a rapid development system and a rapid development method for parallel robots. The rapid development system is provided with a support system, a numerical calculation system, a CAD (Computer Aided Design) system, a CAE (Computer Aided Engineering) system and a control system to provide a design platform support for the rapid development system for parallel robots. The rapid development system is additionally provided with a supporting database which is used for providing a basic support for the system, a resource information management module which is provided with a data exchange interface and is used for the management of the supporting database, a design module which is used for designers to perform theoretical design analysis of the parallel robots, a structural design module which is used for the structural design of the parallel robots, a model verification module which is used for motion simulation analysis of the parallel robots, a CAE simulation design module which is used for simulation analysis, an electromechanical coupling design module which is used for electromechanical coupling simulation design, and an optimization design module which is used for the optimization design of the designed parallel robots. The rapid development system and the rapid development method for parallel robots have the advantages that the integrated design of the parallel robots can be realized and the research, development and design efficiency and quality of the parallel robots are effectively improved.

The invention discloses an electric property prediction method of a cylinder conformal array antenna under load distortion. The method comprises following steps of determining structure parameters and electromagnetic parameters of the cylinder conformal array antenna; carrying out structure load distortion analysis; calculating new positions of array elements after distortion; building an array element rectangular coordinate system and an array element sphere coordinate system, and a conversion matrix between the two coordinate systems; solving an array element directional diagram under the array element rectangular coordinate system; determining a conversion matrix between the array element rectangular coordinate system and an array rectangular coordinate system; solving an array element directional diagram under the array rectangular coordinate system; determining array element execution amplitudes and phases; calculating the space phase difference of each array element; calculating a far region field intensity distribution directional diagram; building an electromechanical coupling model; calculating the electric property parameter of the antenna; and judging whether the calculated electric property parameter satisfies a demand or not. The method can be used for quantitatively evaluating the influence of antenna structure distortion on the electric property of the cylinder conformal array antenna under a load environment, thus instructing the structure design of the cylinder conformal array antenna.

The invention relates to the technical field of inorganic nonmetallic materials, in particular to an additive and the application thereof for reducing the sintering temperature of piezoceramic, wherein the additive takes Pb(Zn1/3Nb2/3)0.1(Ni1/3Nb2/3)0.1Zr0.47Ti0.33) (PZN-PNN-PZT) as a basic formula system; the additive that accounts for 1 to 11 percent of the weight of the basic formula system is added in the basic formula system; and the additive comprises the following ingredients by mass: LiBiO2 accounts for 44 to 65 percent, CuO accounts for 1 to 20 percent, and ZnO-B2O3-Li2O-SiO2 accounts for 25 to 45 percent. The low-temperature sintering piezoceramic that is prepared after the additive is added has the performances as follows: the dielectric constant ranges from 2500 to 3000, the dielectric loss is less than or equals to 2.0 percent, the planar electromechanical coupling factor is more than or equals to 65 percent, the piezoelectric strain constant is more than or equals to 420pC/N, the mechanical quality factor ranges from 100 to 400, and the sintering temperature ranges from 900 to 930 DEG C. The additive and the application thereof can reduce the sintering temperature of piezoceramic so as to obtain the piezoceramic with low-temperature sintering (the sintering temperature ranges from 900 to 930 DEG C) and high piezoelectric properties, can greatly lower the cost of a piezoceramic device, can inhibit the volatilization of lead oxide, and can accord with the environmental protection requirements.