330 results about "Piezoelectric composite" patented technology

The invention discloses a planar phased array ultrasonic transducer, and relates to the technical field of transducers, the planar phased array ultrasonic transducer comprises a 1-3 type piezoelectric composite board, a common positive electrode panel and a flexible circuit board, the 1-3 type piezoelectric composite board comprises a polymer frame and a plurality of PZT piezoelectric ceramic columns, all the PZT piezoelectric ceramic columns are embedded in the polymer frame in an array, and the PZT piezoelectric ceramic columns are connected with the flexible circuit board. One end of each PZT piezoelectric ceramic column is a positive electrode end, the other end of each PZT piezoelectric ceramic column is a negative electrode end, the common positive electrode panel is connected with the positive electrode ends of the PZT piezoelectric ceramic columns, the flexible circuit board is provided with a bonding pad area and at least one pin area, the bonding pad area is fixedly provided with a plurality of bonding pads, the pin area is fixedly provided with a plurality of pins, and the flexible circuit board is provided with a plurality of conductive terminals. All the pins, all the bonding pads and all the negative electrode ends of the PZT piezoelectric ceramic columns are in one-to-one correspondence, the bonding pads are electrically connected with the pins, and the bonding pads are connected with the negative electrode ends of the PZT piezoelectric ceramic columns; according to the invention, the PZT is applied to the planar phased array ultrasonic transducer.

The invention provides a fiber reinforced structure damage positioning method based on a piezoelectric effect, a fiber reinforced structure is widely applied in multiple fields but is easy to damage, an existing positioning method has defects, and the method comprises the steps of piezoelectric composite material preparation, sensor network construction, signal acquisition and processing, positioning based on a time reversal method and the like. During preparation, specific materials are mixed and stirred and then laid with the reinforced fibers, and the processes of curing molding, polarization, packaging and the like are performed; the sensing network is formed by arranging electrodes on the surface of the composite material; signal acquisition is carried out when the composite material deforms or is damaged under load; and the positioning is to re-excite the acquired signal after time reversal processing, and determine a damage point according to a focusing position. The method has the advantages of high-precision positioning, self-energized real-time monitoring, wide applicability, simple and practical structure and the like, can be applied to various fiber reinforced structures, can effectively solve the problems in the prior art, and has important significance for guaranteeing the safety and reliability of the fiber reinforced structures.

The invention provides a piezoelectric composite stent, a preparation method thereof and application of the piezoelectric composite stent in tracheal defect repair, and belongs to the technical field of tissue engineering. The preparation method of the piezoelectric composite stent comprises the following steps: (1) immersing a PLLA stent into an FF polypeptide solution to prepare a PLLA-FF stent; (2) the PLLA-FF stent is immersed in a tannic acid solution, and a PLLA-FF-TA composite stent is prepared; (3) preparing oxygen-containing PLGA (poly (lactic-co-glycolic acid)) nano microbubbles, and mixing the GelMA with the oxygen-containing PLGA nano microbubbles to obtain a Gel-NB hydrogel precursor; (4) injecting the Gel-NB hydrogel precursor into the PLLA-FF-TA composite scaffold, and carrying out ultraviolet light cross-linking on the Gel-NB hydrogel precursor and the PLLA-FF-TA composite scaffold; and carrying out ultrasonic irradiation to obtain the PLLA-FF-TA (at) Gel-Nb + US composite scaffold. The piezoelectric hydrogel stent is successfully prepared, can be well used for tracheal defect repair, has the advantages of good degradation performance, high piezoelectric performance, long-term stability and high strength, and is beneficial to clinical transformation and application.

The present invention provides a surface tension assisted film forming method to prepare a flexible, patterned piezoceramic composite for use in a variety of electronics. The present method allows tuning mechanical and piezoelectric properties of the resulting composite by simply adjusting one or few parameters used during the piezoceramic film forming and / or composite forming procedures in the absence of any complex transferring techniques that are commonly used in conventional methods. The present invention also allows customizing patterns (two-dimensional or three-dimensional) on the piezoceramic framework to result in a piezoelectric composite that is able to provide anisotropic piezoelectric responses to different loads whilst still having a constant electrical output over a long-time deformation.

The invention provides a hybrid-driven MEMS device and a preparation method thereof, and the method comprises the steps: forming a first actuating structure in a first substrate, forming a piezoelectric composite film layer on the first actuating structure, applying voltages with opposite electrical properties to a first electrode layer and a second electrode layer, enabling a piezoelectric layer to deform under the effect of an inverse piezoelectric effect, and enabling the piezoelectric composite film layer to form a piezoelectric composite film layer; the movable end of the first actuating structure is driven to move; a second cavity is formed in the second substrate, a third electrode layer is formed in the second cavity, voltage which is the same as or opposite to that of the second electrode layer is applied to the third electrode layer, and the third electrode layer and the second electrode layer serve as electrodes for electrostatic driving. According to the MEMS device, the first actuating structure and the second actuating structure are arranged, so that the deformation deflection of the movable end of the first actuating structure is further increased on the basis of displacement generated by piezoelectric driving, the hybrid-driven MEMS device is formed, the defects of independent driving of piezoelectric driving and electrostatic driving are overcome, and the MEMS device can achieve larger displacement under the same voltage during accurate deflection.

The invention relates to a flexible and high-strength composite piezoelectric fiber film as well as a preparation method and application thereof, and the preparation method comprises the following steps: dissolving PVDF (Polyvinylidene Fluoride) or a copolymer thereof in a solvent to obtain a first solution; dissolving a strong dipole moment asymmetric polar inorganic metal salt in a solvent to obtain a second solution; uniformly mixing the first solution and the second solution, adding the multifunctional bio-based polymer, performing ultrasonic stirring until a uniform composite spinning solution is formed, and performing electrostatic spinning to obtain the composite piezoelectric fiber film. The fiber film provided by the invention integrates the mechanical strength and chemical stability of PVDF and copolymer thereof and the flexibility and water absorption of bio-based polymer. Meanwhile, inorganic metal salt is introduced to play a role of a beta-phase nucleating agent in the electrostatic spinning PVDF crystallization process, the piezoelectric output performance of the electrostatic spinning PVDF nano piezoelectric composite film is enhanced, and the mechanical performance of the fiber film is improved through the metal coordination effect of metal ions and hydroxyl or carboxyl on the bio-based polymer; the application potential in the fields of sensors, battery diaphragms, antibacterial coatings and the like is expanded.

The invention belongs to the crossing field of biomedical engineering and additive manufacturing, and particularly relates to a 3D printing metamaterial piezoelectric bone defect repair scaffold, and the pore structure of the scaffold is formed by compounding three extremely small curved surface units, namely Gyandroid, SchwarzP and Diamond, which are defined by mathematical expressions; the porosity of the stent is 30%-70%, and the pore diameter range is 0.1-1 mm; the stent is made of a piezoelectric composite material composed of polyvinylidene fluoride (PVDF), polylactic acid and barium titanate, the piezoelectric composite material comprises the following components in percentage by mass: 30%-55% of polyvinylidene fluoride (PVDF), 20%-45% of polylactic acid (PLA) and 10%-25% of barium titanate (BaTiO3), and the sum of the mass percentages of all the components is 100%. Precise regulation and control of a macrostructure and a microstructure are achieved through a multi-material 3D printing technology, and the system has the mechanical adaptability, degradation controllability and the function of actively promoting bone regeneration and is suitable for large-section bone defect repair scenes such as craniomaxillofacial and long bones of four limbs.

The invention relates to the technical field of battery management, in particular to a modular intelligent battery management system, which comprises a sensing module for realizing full-dimensional monitoring of a battery through a multi-mode sensor array, implanting an MEMS stress sensing network and constructing a holographic stress tensor model; the operation and maintenance and decision-making module is used for realizing cooperative control of the battery units through dynamic impedance matrix construction, plasma resonance frequency monitoring and unbalanced thermodynamic gradient analysis; and the execution module is used for receiving the instruction sent by the stress analysis and optimization unit, controlling the piezoelectric composite material to generate a self-adaptive support structure, adjusting the internal mechanical structure of the battery, forming a stress shielding area and reducing the influence of stress on the performance and the service life of the battery. Through a dynamic impedance matrix and a main control unit election mechanism, the single-point bottleneck of traditional centralized management is avoided, and even if part of units fail, the system can still maintain the function through matrix recombination, so that the anti-interference capability and reliability are improved.

The invention discloses a paper folding type piezoelectric energy collector for collecting low-frequency energy. The paper folding type piezoelectric energy collector comprises a piezoelectric composite material paper folding cylindrical structure and two side end faces. The piezoelectric composite material origami cylindrical structure is obtained by bending and folding a planar piezoelectric composite material along a peak fold line and a valley fold line. In the bending process, the bent piezoelectric ceramic composite material can be manufactured by controlling external force in the sintering process. According to the invention, piezoelectric ceramic 3D printing is combined with a novel material inspired by paper folding. The piezoelectric ceramic suspension is used as 3D printing ink. The novel material structure is based on a Kresling origami cylindrical surface, but creases are hidden, the effective collection area is increased, and the electrical performance is improved. The multi-stable Kresling origami structure has low rigidity and a low energy barrier, so that energy collection in a low-frequency environment becomes possible, and the multi-stable Kresling origami structure is particularly suitable for ocean wave energy collection application.

The invention discloses an Internet of Things and AI energized smart energy multi-energy complementary heating control system, which relates to the technical field of smart energy heating control, and comprises an atomic layer deposition sensing module for realizing ultra-sensitive measurement of temperature and humidity; edge nodes are calculated through photons, and the data processing energy efficiency is improved; the shape memory alloy-piezoelectric composite execution module is used for accurate and rapid adjustment; the multi-scale heat coordination module is used for strengthening heat transmission; the magnetofluid sealing and regulating module is used for dynamically controlling the flow; the terahertz metasurface communication module guarantees high-speed communication, and the system optimizes energy complementation and intelligent regulation and control through multi-technology fusion. According to the invention, the sensing precision, the data processing speed and the execution precision are improved, the heat transmission efficiency is enhanced, the flow dynamic regulation and control and high-speed reliable communication are realized, the room temperature standard reaching rate is improved and the energy consumption is reduced through digital twin optimization control, and an efficient low-carbon scheme is provided for smart energy heating.

The invention belongs to the technical field of fluid mechanical control, and particularly relates to an integrated water pump energy-saving control system which comprises a heterogeneous sensing array, an intelligent optimization controller, a dual-mode energy recovery device, a multi-scale feature analysis module and a cloud platform diagnosis system. The heterogeneous sensing array comprises pressure gradient sensors, multi-frequency voiceprint sensors and an electromagnetic-ultrasonic composite flowmeter, the pressure gradient sensors are arranged at 0.5 D intervals in the axial direction of the pipeline, the voiceprint sensors are provided with Helmholtz resonant cavities, and the composite flowmeter automatically switches electromagnetic / ultrasonic measurement modes according to Reynolds numbers. A dual-mode energy recovery device is adopted, control optimization energy saving and energy recovery energy saving are achieved, the comprehensive energy saving amount reaches 33.7%, the flywheel-piezoelectric composite energy storage system achieves 82% of energy conversion efficiency, and compared with a traditional single mode, the energy conversion efficiency is improved by 19.6%.

Described herein are aspects of a three-dimensional (3D) piezoelectric structure that can be composed of a 3D periodic microlattice that can be composed of a piezoelectric composite material, wherein the 3D periodic microlattice can include a plurality of interconnected 3D node units capable of generating a piezoelectric response upon application of a stress to the 3D periodic microlattice, and wherein the plurality of interconnected 3D node units can form a tailored piezoelectric tensor space. Also described herein are systems that can include one or more of the 3D piezoelectric structures described herein. Also described herein are methods of making and using the 3D piezoelectric structures described herein.

The present invention discloses a rotary underwater fish-aggregating power generation device and its operating method, comprising a float, a power generation module, and a payload module; the payload module includes a housing, a rechargeable power source, a lifting unit, a storage box, and a pressure pump; the power generation module includes a main column, a rotating bearing, brushes, Q rotating frames, a sealing sleeve, and a main delivery pipe. The present invention utilizes a rotary structure to securely attach a piezoelectric composite flexible membrane to the main column and rotating frame, such as a cantilever beam. A mixture of fish-aggregating element and feed is released outward at different locations on the power generation carrier to attract fish to the device. The piezoelectric composite flexible membrane is bent and deformed by the water flow and the fish, generating and storing current. The present invention can be mounted on a payload for simultaneous use, enhancing endurance during cable-free operations in deep waters and continuous, long-term ocean exploration missions. It offers excellent concealment and utilizes the marine environment to generate electricity, but the device does not require special installation or active implantation onto marine organisms.

An air-coupled ultrasonic scanning platform for an air-coupled ultrasonic non-contact metrology of battery electrodes that maps the local variation in density and thickness, and detect defects during electrode casting and drying, includes: piezocomposite air-coupled transducers (Ultran) at 0.5 to 1 MHz that provide sufficient air coupling to enable sound waves to travel through air from a transmitting transducer, through the thin film electrode coated on metal current collector, and then into the receiving transducer. Non-contact, air-coupled ultrasound may be used as a technique for evaluating battery electrode films. An analytical model was derived from fundamental acoustic wave propagation principles to determine acoustic density. Voltage gain or acoustic density maps of electrode films revealed features that are not visually apparent, attributed to mass gradients.

The invention relates to a semi-active pressure-resistant low-frequency sound absorption covering layer containing a piezoelectric composite material. The semi-active pressure-resistant low-frequency sound-absorbing covering layer containing the piezoelectric composite material structurally comprises a surface protecting layer which is arranged on the outermost side of the covering layer and converts sound energy into heat energy through a damping effect; the piezoelectric composite material layer is arranged on the inner side of the surface protection layer, converts sound energy into electric energy through a direct piezoelectric effect, and dissipates the electric energy through a shunt branch; the cavity layer is arranged on the inner side of the piezoelectric composite material layer and absorbs sound through a cavity resonance effect, waveform conversion and a damping effect; the substrate layer is arranged on the inner side of the cavity layer to seal the cavity layer so as to absorb sound with a damping effect; wherein the composite material layer is electrically connected with an external shunt branch, and the shunt branch is formed by connecting a negative capacitance element, a resistance element and an inductance element in series.

The invention discloses piezoelectric catalysis-Fenton self-coupling staged underground water treatment equipment, and relates to the technical field of underground water pollution abatement, the piezoelectric catalysis-Fenton self-coupling staged underground water treatment equipment comprises a reactor main body, a piezoelectric-aeration water treatment module and a PVDF-HFP piezoelectric film array, the piezoelectric-aeration water treatment module is fixedly arranged in a piezoelectric-aeration catalysis reaction zone, and the PVDF-HFP piezoelectric film array is fixedly arranged in the reactor main body; the PVDF-HFP piezoelectric film array is fixedly arranged in the Fenton-piezoelectric catalysis enhanced reaction zone; the piezoelectric-aeration water treatment module comprises a micro-nano bubble generator, a micro-nano diaphragm and a piezoelectric composite filler, a filler containing cavity is formed between the micro-nano bubble generator and the micro-nano diaphragm, and the piezoelectric composite filler is filled in the filler containing cavity; the micro-nano bubble generator is connected with the dissolved air pump through a first air inlet pipe; and a Fenton filler is loaded on the surface of the PVDF-HFP piezoelectric film array. According to the invention, high-efficiency and low-consumption remediation and treatment of the water body can be realized in an underground water environment.

The invention discloses an elasticity-enhanced electromagnetic-piezoelectric composite energy harvesting device and method, and belongs to the technical field of energy harvesting. Comprising a shell, sleeve mechanisms are arranged on the two sides of the upper portion in the shell, a permanent magnet is installed between the two sleeve mechanisms, a U-shaped soft magnetic core installed on a clamping sleeve is arranged below the permanent magnet, the U-shaped soft magnetic core is sleeved with a coil, and an elastic connecting piece connected with the bottom of the inner surface of the shell is arranged in the center of the bottom of the clamping sleeve. A plurality of piezoelectric patches arranged at equal intervals are attached to the two sides of the outer surface of the elastic connecting piece, and the piezoelectric patches and the coil are connected with a power management module. According to the invention, the elastic device is added to enable the magnet and the magnetic core to perform more interactive motion, the power generation efficiency is improved, and the piezoelectric plate is added on the elastic device to make full use of the energy. An electromagnetic-piezoelectric type ocean energy capturing device is formed, and the energy collecting efficiency is greatly improved.

The invention relates to the technical field of machine testing, and particularly discloses an on-orbit vibration monitoring and characteristic parameter identification system and method for a spacecraft, and the system judges whether to carry out early warning prompt on a flexible piezoelectric compound sensor or not by obtaining an abnormal index of the sensor. Then, the flexible piezoelectric compound sensor carries out on-orbit vibration monitoring on a monitoring area to which the spacecraft belongs so as to obtain a vibration electric signal of the monitoring area to which the spacecraft belongs, and the vibration electric signal is processed by the data acquisition platform to obtain a vibration digital signal; meanwhile, the spacecraft vibration monitoring platform obtains a vibration data transmission abnormal index of the vibration digital signal in the transmission process, and judges whether the transmission process between the data acquisition platform and the spacecraft vibration monitoring platform is optimized or not; the vibration digital signal is processed through the spacecraft vibration monitoring platform to obtain the safety characteristic evaluation value of the monitoring area to which the spacecraft belongs, whether safety early warning prompt is carried out or not is judged, and accuracy and high efficiency of on-orbit vibration monitoring and characteristic parameter identification of the spacecraft are ensured.

The utility model provides a novel multilayer heterogeneous bonding substrate structure, which belongs to the field of piezoelectric composite materials, and comprises a functional substrate layer and a wafer structure layer, the functional substrate layer comprises a first substrate layer, and a functional element and a device layer which are manufactured on the surface of the first substrate layer; the wafer structure layer comprises a second substrate layer, an absorption layer, an isolation layer and a piezoelectric film layer which are sequentially arranged from bottom to top, a bonding layer is arranged between the functional substrate layer and the wafer structure layer, and the bottom surface of the wafer structure layer is aligned with the front surface of the functional substrate layer and is connected with the front surface of the functional substrate layer in various bonding modes at the bonding layer. The wafer structure layer is provided with a plated-through hole, two ends of the plated-through hole are respectively provided with a top metal panel and a bottom panel, the top metal panel is arranged at the top of the wafer structure layer, and the bottom panel is arranged at the bottom of the bonding layer. The method has the advantages of short connection distance, high Q value, good reliability and high space integration level, and is higher in batch production efficiency and more convenient to change wafer materials, functional elements and device manufacturing parameters.

The invention provides a spherical hollow piezoelectric composite material and a preparation method thereof, and belongs to the technical field of piezoelectric materials. According to the method disclosed by the invention, the precise manufacturing of the complex three-dimensional structure of the piezoelectric composite material is realized, and the controllability of the structure can be realized; a 1-3 type (namely a two-phase piezoelectric composite material composed of one-dimensionally arranged piezoelectric phases and three-dimensionally communicated polymer phases) piezoelectric composite material is of a periodic array structure formed by embedding piezoelectric ceramic columns into a resin matrix, and precise arrangement and complex three-dimensional shape control of the ceramic columns are difficult to realize by a traditional process. According to the 3D photocuring printing technology, liquid photosensitive resin is cured layer by layer, so that the diameter, spacing and spatial distribution of piezoelectric materials (such as ceramic columns) can be accurately controlled, complex structures such as a spherical polymer hollow frame are formed, and the degree of freedom of material design is remarkably improved.

The invention discloses a strain piezoelectric composite rotor balance, and belongs to the technical field of wind tunnel tests. Comprising a floating frame, a fixed frame and a force sensing unit. The force sensing unit is arranged between the floating frame and the fixed frame; a strain type force sensor, a piezoelectric type force sensor, a decoupling connecting rod and a sliding block capable of adjusting pre-tightening force are arranged in the force sensing unit; according to the scheme, simultaneous high-precision measurement of the static load and the high-frequency vibration load of the rotor wing is realized by using the characteristics of high static measurement precision of the strain type force sensor, wide dynamic measurement frequency band of the piezoelectric type force sensor and the decoupling effect of the decoupling connecting rod.

The invention discloses a polyaryletherketone composite implant material and a preparation method and application thereof, and belongs to the technical field of medical materials.The preparation method of the polyaryletherketone composite implant material comprises the following steps that a carbon fiber reinforced polyaryletherketone substrate with the surface provided with a groove structure and conductivity is prepared; based on a precipitation method, a calcium compound, a magnesium compound and a phosphoric acid aqueous solution are used for preparing white calcium stone; the preparation method comprises the following steps: carrying out surface modification on the white calcium phosphate by utilizing polydopamine, so as to obtain modified white calcium phosphate; adding the modified white calcium phosphate and a degradable piezoelectric polymer into a solvent, and mixing to obtain a mixed solution; and coating a carbon fiber reinforced polyaryletherketone substrate with the mixed solution, and performing drying and annealing treatment to form a coating, thereby obtaining the polyaryletherketone composite implant material. According to the invention, the degradable piezoelectric composite coating doped with the white phosphorus calcium stone, which has piezoelectric characteristics and ion release capability, is constructed, so that double biomimetic effects of an electric signal and a chemical signal in a bone healing microenvironment are realized.

This invention discloses a finite element design and analysis method for a novel structural piezoelectric composite material. The method includes the following steps: extracting the zero level set surface based on the spatial structural equation to create the geometric shapes of a 3D TPMS shell structure, including Schwarz P, Gyroid, Neovius, and Diamond structures; using Matlab to define the frame volume fraction of the geometric shapes and control the unit node information in the 3D TPMS shell structure model; generating the 3D TPMS shell structure model as an inp file, importing the inp file into Abaqus to generate hexahedral elements; using Rhino to smooth the surface of the hexahedral elements, exporting the STL file, and performing remeshing in Hypermesh to convert the hexahedral elements into tetrahedral elements; adding periodic boundary conditions to the tetrahedral element mesh and performing numerical simulation to obtain the TPMS shell structure composite material model. The novel TPMS shell structure piezoelectric composite material designed by this method significantly improves piezoelectric performance compared to existing piezoelectric composite materials.

The invention discloses a bending-shearing coupling type acceleration sensor and a forming method thereof, and belongs to the field of sensors, the bending-shearing coupling type acceleration sensor comprises an upper shell and a lower shell, an internal thread and a step are arranged in the upper shell, an external thread is arranged on the lower shell, and the upper shell and the lower shell are in threaded connection and jointly define a containing cavity; a metal piezoelectric composite sensitive element, a first mass block, a screw rod and a second mass block are arranged in the containing cavity, the metal piezoelectric composite sensitive element comprises a piezoelectric plate group, an electrode plate group and a second electrode plate, and the piezoelectric plate group comprises a first piezoelectric plate and a second piezoelectric plate which are radially polarized and opposite in polarization direction; the electrode plate group comprises a first electrode plate and a third electrode plate, the first electrode plate, the first piezoelectric plate, the second electrode plate, the second piezoelectric plate and the third electrode plate are sequentially and coaxially arranged and bonded, and the edge of the metal piezoelectric composite sensitive element is tightly pressed between the upper shell and the lower shell. And the charge sensitivity of the acceleration sensor is improved by utilizing the bending-shearing coupling effect of the radial polarization piezoelectric material.

The utility model provides an MEMS piezoelectric sounder and a loudspeaker, first piezoelectric composite layers are symmetrically arranged at specified edge positions, a plurality of slotted structures are arranged in a specified area, a first diaphragm edge of a formed diaphragm structure is an anchoring edge, and an edge slotted structure is arranged at a non-anchoring edge. The internal stress of each diaphragm layer in the diaphragm structure caused by the process can be reduced by arranging the slotting structure, the flexibility of the diaphragm structure can be improved by covering the slotting structure with the flexible material, meanwhile, the sound leakage of the MEMS piezoelectric sounder at low frequency is reduced, the vibration amplitude and the emission sound pressure level of the MEMS piezoelectric sounder are improved, and the sound quality of the MEMS piezoelectric sounder is improved. According to the MEMS piezoelectric sounder, the flexible material with low density is adopted to replace a silicon vibrating diaphragm with large density, the mass of the vibrating diaphragm structure is reduced, the vibrating diaphragm structure of the rectangular bridge type structure can push out more air, the flexible material increases system damping, a sound pressure level SPL frequency response curve and a THD frequency response curve can be improved, and therefore the tone quality of the MEMS piezoelectric sounder is improved.

The invention relates to a dielectric elastomer-piezoelectric composite multi-source energy collection device for a non-intrusive electric field sensor, and belongs to the technical field of power system self-powered sensors. The device comprises a base, a dielectric elastomer unit, a piezoelectric cantilever beam, a mass block and a rectification energy storage circuit. The dielectric elastomer deforms under the action of an alternating electric field, the piezoelectric cantilever beam is driven through coupling to generate mechanical vibration, and the piezoelectric layer further converts mechanical energy into electric energy to be output. The resonant frequency of the system is adjusted by setting the mass block, so that the resonant frequency is matched with the external electric field frequency or the environment vibration frequency, and the energy conversion efficiency is optimized. The device can collect external electric field energy in a non-intrusive mode and provide a stable power supply required by a low-power-consumption sensor. The device is compact in structure, high in sensitivity and suitable for electric field monitoring in scenes such as ultrahigh-voltage power transmission lines and transformer substations, and provides reliable energy support for self-powered sensors of power equipment.

The invention provides a focused ultrasonic transducer based on a phase reversal Fresnel lens and a preparation method. The focused ultrasonic transducer comprises the phase reversal Fresnel lens, a matching layer, a piezoelectric layer made of 1-3 piezoelectric composite materials and an epoxy tungsten backing layer. By means of the structural design that the phase reversal Fresnel lens is used for achieving 180-degree phase reversal, the transducer can achieve a stronger sound field focusing effect in a near-field area with a smaller size, and the problems that a traditional transducer is large in size and poor in curvature adaptability, and focusing depends on a complex circuit are solved.

The invention discloses a high-precision self-adaptive control method and system for a floating sealing device of a lithium extraction rotary kiln, and relates to the technical field of intelligent control, and the method comprises the steps: collecting the multi-modal characteristic parameters of the operation state of the rotary kiln, inputting the multi-modal characteristic parameters into a physical information neural network, solving a thermoelastic mechanical partial differential equation, and obtaining the high-precision self-adaptive control of the floating sealing device of the lithium extraction rotary kiln. The method comprises the steps of obtaining a deformation field prediction matrix, outputting a deformation field prediction matrix, solving a multi-target optimization model with minimum leakage rate and wear energy consumption as a joint target based on the deformation field prediction matrix, outputting a sealing compensation instruction vector, and driving a magneto-rheological-piezoelectric composite execution mechanism to complete instruction control of a sealing ring based on the sealing compensation instruction vector. Collecting feedback result data controlled by the instruction, adjusting the weight of each weight coefficient in the multi-objective optimization function on line by adopting a reinforcement learning algorithm based on the feedback result data, and feeding back the adjusted weight to the multi-objective optimization model; and the control stability of the rotary kiln under complex working conditions is ensured.

Parts made by additive manufacturing are often structural in nature, rather than having functional properties conveyed by a polymer or other component. Printed parts having piezoelectric properties may be formed using compositions comprising a plurality of piezoelectric particles non-covalently interacting with at least a portion of a polymer material via π-π bonding, hydrogen bonding, electrostatic interactions stronger than van der Waals interactions, or any combination thereof. The piezoelectric particles may be dispersed in the polymer material and remain substantially non-agglomerated when combined with the polymer material. The polymer material may comprise at least one thermoplastic polymer, optionally further including a polymer precursor. The compositions may define an extrudable material that is a composite having a form factor such as a composite filament, a composite pellet, a composite powder, or a composite paste. Additive manufacturing processes using the compositions may comprise forming a printed part by depositing the compositions layer-by-layer.

According to the antibacterial zirconia false tooth porcelain block material and the preparation method thereof, a piezoelectric ceramic material is added into the zirconia false tooth porcelain block material, and the piezoelectric discharge characteristic of the piezoelectric composite material is utilized, that is, in the daily food chewing process of a human body, the piezoelectric ceramic material can be used as a piezoelectric ceramic material; the piezoelectric potential generated by the periodic compression mechanical vibration of the zirconia false tooth material is catalyzed to generate reactive oxygen species (ROS) to kill bacteria, so that the false tooth achieves the bacteriostatic effect in the use process, and the bacteriostatic effect is stable and efficient; the technical problems that an existing antibacterial zirconia false tooth material is high in cost due to the fact that silver ions are used, and the sterilization performance is reduced after the antibacterial zirconia false tooth material is used are effectively solved.