185 results about "Interfacial polarization" patented technology

The invention discloses an aluminum electrolytic capacitor state evaluation method and device, and the method comprises the steps: carrying out the frequency scanning measurement of an electrolyte and oxidation film interface, and obtaining the change data of an interface polarization current phase angle along with the frequency; measuring fluid dynamic characteristics of the electrolyte according to the polarization characteristic parameters, and detecting micro-flow response characteristics; according to the flow distribution data and the evolution data, applying a voltage sequence to carry out ion migration kinetic analysis; carrying out microstructure analysis in a preset temperature change process according to the ion distribution characteristics; and according to the structure change data and the dielectric response data, analyzing the change characteristics of the molecular level, the bubble distribution and the overall performance to obtain a stability evaluation result. According to the technical scheme, through multi-dimensional analysis of the interface polarization characteristic, the fluid dynamic characteristic, the ion migration dynamics and the microstructure change of the electrolyte, effective detection of bubbles and layering phenomena in the electrolyte is realized, and accurate evaluation of the performance state of the capacitor is facilitated.

The invention relates to the field of super-hydrophobic materials, in particular to a basalt fiber composite material as well as a preparation method and application thereof. According to the composite fabric material provided by the invention, a multistage micro-nano rough surface of the MoS2 nanoflowers and the silver nanoparticles is constructed on the fiber substrate, so that not only is super-hydrophobic self-cleaning realized, but also the anti-icing performance is relatively high, and particularly, rapid heating is realized by combining broadband absorption of the MoS2 nanoflowers and a local surface plasma resonance effect of the silver nanoparticles; and meanwhile, the silver nanoparticles accelerate heat conduction, so that excellent ice melting capability is obtained. The high conductivity of the silver nanoparticles constructs a conductive path, and the layered structure of MoS2 triggers interface polarization, so that the electromagnetic shielding effectiveness of the X wave band is improved. The dual antibacterial mechanism of the MoS2 nanoflowers and the silver nanoparticles also realizes broad-spectrum efficient antibiosis, the preparation method is green and environment-friendly, the cost is low, and the requirements of complex scenes such as wearable electronic equipment, medical protection, polar region protection and national defense can be met.

The invention relates to the technical field of material detection, and discloses an identification analysis and method for recessive degradation of a flexible conductive composite material, and the system comprises a perturbation excitation module, a response collection module, a time sequence feature extraction module, a micro-response trend consistency analysis module, and a state evaluation and early warning module. Multiple periods of small-signal capacitance excitation are applied to the material, pi-pi stacking slippage and interface polarization behaviors in a conductive network are excited, electrical response data are collected to construct a time sequence feature vector, and the deviation degree of the evolution trend is further calculated. And based on the trend deviation index, performing health state scoring and triggering early warning, thereby realizing early recognition and evaluation of material recessive degradation.

The invention relates to the technical field of wave-absorbing materials, in particular to a preparation method of an MXene-NiO-PPy ternary composite wave-absorbing material. The invention provides a preparation method of an MXene-NiO-PPy ternary composite wave-absorbing material, which comprises the following steps of: etching titanium aluminum carbide powder through a LiF / HCl mixture, and performing ultrasonic stripping to prepare a uniform dispersion of MXene nanosheets; the preparation method comprises the following steps: dispersing MXene nanosheets in a solution of water and absolute ethyl alcohol, and adding a pyrrole monomer and a FeCl3. 6H2O aqueous solution for reaction; after the reaction, washing is performed to obtain a PPy-MXene composite material; the preparation method comprises the following steps: by taking NiCl2. 6H2O as a nickel source and sodium oxalate as a precipitator, preparing NiO nanowires by adopting a hydrothermal method combined with a calcining process; the invention discloses a preparation method of an MXene-NiO-PPy ternary composite wave-absorbing material.According to the method, the MXene-NiO-PPy ternary composite wave-absorbing material with rich heterogeneous interfaces and a porous micro-nano structure is constructed, cooperation of dielectric loss, magnetic loss and interface polarization loss is achieved, and finally the light, efficient and broadband wave-absorbing performance is obtained.

The invention discloses a preparation method of a beaded cobalt-doped Bi25FeO40 / BiFeO3 nanofiber wave-absorbing material, which comprises the following steps: obtaining a precursor by a standing method, and adding the precursor, bismuth nitrate, ferric nitrate and a spinning aid into a mixed solvent compounded by N, N-dimethylformamide and absolute ethyl alcohol to obtain a spinning solution; spinning the spinning solution by adopting an electrostatic spinning technology to obtain a nanofiber membrane; and finally, drying and calcining to obtain the wave-absorbing material. According to the wave-absorbing material, multiple reflection and scattering of electromagnetic waves are increased, the absorption performance of the electromagnetic waves is improved, due to the fact that a heterogeneous interface is generated after two phases are compounded, the interface polarization loss is further increased, when the thickness of the wave-absorbing material is 2.33 mm, the minimum reflection loss reaches-56.01 dB, the effective absorption frequency band width is 6.32 GHz, and the whole Ku wave band is covered.

The invention relates to a preparation method of a lightweight reduced graphene oxide-silicon dioxide electromagnetic wave absorbing material. The invention belongs to the technical field of electromagnetic wave absorbing materials. The invention solves the problems that the impedance of the existing reduced graphene oxide is mismatched, the density of the modified reduced graphene oxide composite wave-absorbing material is increased and the preparation method is complicated. The method comprises the following steps: performing chemical crosslinking on graphene oxide, silicon dioxide and a silane coupling agent to obtain a precursor; and drying and sintering the precursor. The material prepared in the invention has good impedance matching and abundant interface polarization and relaxation effects, can effectively reduce the reflection loss value of electromagnetic waves and increase the effective absorption bandwidth of the electromagnetic waves, and has excellent electromagnetic wave absorption performance. When the thickness of the material is only 1.5 mm, the RL of the material can reach-54.08 dB, and when the thickness of the material is 1.7 mm, the effective absorption bandwidth of the material can reach 5.12 GHz. In addition, the density of the material is only 0.083 g / cm < 3 >, the process is simple, and stable batch production can be realized.

The invention discloses an MgO-C nano chain, a preparation method thereof and application of the MgO-C nano chain as a wave-absorbing material, a horizontal tube furnace is adopted for preparation, and an evaporation area and a reduction area are arranged at the two ends of a furnace body respectively; taking Mg (acac) 2 as a precursor, and placing the precursor in an evaporation area; placing a substrate for collecting products in a reduction area; inert gas is adopted as carrier gas and reaction atmosphere, a vacuum pump system is used for maintaining the internal pressure intensity of the system, reaction is conducted, and the MgO-C nano chain is collected on the substrate. In the MgO-C nano chain, the nano MgO particles are connected into a three-dimensional structure through carbon, the wave-absorbing effects such as interface polarization and multiple scattering reflection are enhanced by means of the unique structure, the wave-absorbing performance is greatly improved, and the frequency band is widened. The material has good microwave absorption performance, and has a very good application prospect in the fields of stealth technology and electromagnetic shielding.

The invention belongs to the technical field of preparation of wave-absorbing materials, and particularly relates to a cobalt-based nitrogen-doped carbon nano composite material with a hollow cubic structure as well as a preparation method and application thereof. Comprising the following steps: taking ZnCo-ZIF with a nano cubic structure as a core, coating ZnCo-ZIF with polydopamine by adopting a precipitation method to form a precursor with a core-shell structure, and carbonizing the precursor at 800-900 DEG C to obtain the cobalt-based nitrogen-doped carbon nano composite material with the hollow cubic structure. According to the invention, the dielectric loss capability can be enhanced by using the conductivity and interface polarization effect of the coated carbon layer, and the Co particles introduce strong magnetic loss; meanwhile, due to interface polarization caused by abundant heterogeneous interfaces existing between the Co particles and the coating carbon layer, between the magnetic particles and the carbon nanotubes and between the carbon matrix and the carbon nanotubes in the composite material, the impedance matching characteristic can be improved, and high reflection loss and wide effective absorption bandwidth can be achieved under the low matching thickness.

The invention discloses a silicone rubber dielectric elastomer composite material and a preparation method thereof. The preparation method comprises the following steps: preparing a silicon carbide MXene dispersion liquid and a silicone rubber solution; mixing the carbon nano tube with the MXene dispersion liquid to form a stable MXene-carbon nano tube hybrid filler suspension liquid; uniformly mixing the MXene-carbon nanotube hybrid filler suspension with a silicone rubber solution, and adding a coupling agent and a vulcanizing agent to obtain a mixed solution; carrying out evaporation heat treatment on the prepared mixed solution; two-dimensional silicon carbide MXene and one-dimensional carbon nanotubes are hybridized to serve as filler, an interface layer is formed to firmly wrap the carbon nanotubes and silicon carbide MXene, the isolation and stabilization effects are achieved, the conditions of agglomeration and aggregation of the filler are effectively avoided, and under the action of a silane coupling agent, the carbon nanotubes and the silicon carbide MXene are mixed to serve as the filler. The filler can be more uniformly dispersed in the silicone rubber matrix, so that the composite material has a relatively strong interface polarization effect, thereby having a relatively high dielectric constant, keeping the dielectric loss in a relatively low range, and having relatively good mechanical properties.

The invention belongs to the technical field of waste lithium battery recovery, and particularly relates to a method for selectively extracting lithium from a waste lithium iron phosphate positive electrode material based on interface polarization activation-complexing impurity inhibition, which comprises the following steps: 1) adding the waste lithium iron phosphate positive electrode material, an oxidizing agent and an activating agent into a solvent, stirring and leaching, and carrying out solid-liquid separation after leaching to obtain a leaching solution; and (2) adding inorganic salt into the leachate, enabling the inorganic salt and the activating agent in the step (S1) to generate precipitate, and carrying out solid-liquid separation to obtain a lithium-rich solution. Through the synergistic effect of the activating agent and the oxidizing agent, the lithium is deintercalated while the main body of the waste lithium iron phosphate positive electrode material is not dissolved basically, the leaching rate of the lithium can reach 99% or above, and the content of iron and phosphorus impurities in the lithium-rich solution is low. The method has the advantages of being high in lithium leaching rate, good in lithium selectivity, wide in leaching temperature application range, short in technological process, few in generated waste and low in cost, and particularly, the method also has the excellent selective lithium leaching effect at the low temperature.

The invention discloses an electromagnetic wave absorbing material CoFe2O4 / ZnO-RGO with a ternary heterostructure as well as a preparation method and application of the electromagnetic wave absorbing material CoFe2O4 / ZnO-RGO, and belongs to the technical field of electromagnetic wave absorption. According to the material, a novel heterostructure with a multi-scale interface and a three-dimensional conductive network is constructed by compounding magnetic loss type CoFe2O4, dielectric loss type ZnO nanorods and resistance loss type RGO. Wherein the ZnO nanorod not only serves as a dielectric loss body, but also effectively enhances the structural anisotropy and the interface polarization effect of the material, and cooperates with the magnetic loss of CoFe2O4 and the resistance loss of RGO to jointly optimize impedance matching and improve the electromagnetic attenuation capability, so that the material shows excellent wave-absorbing performance under various thickness and even ultrathin conditions. The material source is wide, the cost is low, the preparation process is green, simple and convenient, the material is suitable for large-scale production, and an effective material solution is provided for electromagnetic wave absorption application in the national defense and civil fields.

The invention relates to the technical field of power system state monitoring, and discloses an insulator defect detection method and device and a storage medium, and the method comprises the steps: collecting the leakage current of an insulator, and constructing a polarity conduction screening model through power frequency phase information, so as to generate a composite current sequence which highlights the polarization attribute of an interface; analyzing the nonlinear degree of the attenuation rate of the sequence drifting along with evolution time in a multi-stage diffusion evolution time domain, and generating an interface electrochemical mass transfer composite index; utilizing the index to invert and construct an interface polarization background reference and stripping the interface polarization background reference from the composite current sequence so as to extract an abnormal discharge pulse residual error; and finally, quantizing the pulse form distortion degree of the residual error, and performing suppression normalization operation on the distortion degree by using the index to output a judgment result. According to the invention, the interference of the interface mass transfer process is effectively eliminated, and the specific detection of the pollution flashover hidden danger is realized.

The invention belongs to the field of cable insulation material preparation, and particularly relates to a polypropylene insulation direct current cable and a preparation method thereof. The direct-current cable polypropylene insulation material provided by the invention comprises the following components in parts by weight: 100 parts of PP, 5-15 parts of EPDM and 1-5 parts of nano MgO. According to the invention, the problem of poor dispersibility of EPDM particles on a PP matrix is solved by improving the preparation process (increasing the extrusion molding pressure and the injection molding temperature, and carrying out stepped cooling). By adding the EPDM elastomer of the nano filler, the flexibility and distortion resistance of polypropylene insulation are improved, and the interface polarization phenomenon between the EPDM elastomer and polypropylene is improved, so that the electrical performance can be improved while the mechanical performance is improved.

The invention discloses a Fe3C (at) C assembled nano wave-absorbing structure and a preparation method thereof, and the preparation method comprises the following steps: synthesizing Fe2O3 (at) C spheres through a hydrothermal method, carrying out carbon removal treatment on the Fe2O3 (at) C spheres by adopting an air oxidation method to obtain a Fe2O3 hollow sphere precursor, and finally carrying out chemical vapor deposition (CVD) reaction on the obtained Fe2O3 hollow sphere precursor to convert a Fe2O3 phase in the Fe2O3 hollow sphere precursor into a Fe3C phase to form Fe3C hollow spheres, thereby obtaining the Fe3C assembled nano wave-absorbing structure. And growing a C nano-particle array on the surface of the Fe3C hollow sphere in situ so as to obtain the Fe3C-C assembled nano wave-absorbing structure. The problems that an existing magnetic wave-absorbing material is large in density, poor in impedance matching, low in electromagnetic wave loss efficiency and the like are solved. According to the prepared nano wave-absorbing structure, coupling of dielectric loss and magnetic loss and optimization of impedance matching are easily achieved, the multiple scattering effect of electromagnetic waves is greatly enhanced through the C nano-particle array structure and the hollow structure on the surface of the nano wave-absorbing structure, enhancement of the interface polarization relaxation loss effect is promoted through a large number of Fe3C-C heterogeneous interfaces, and the wave-absorbing performance is improved.

The invention discloses a preparation method of a boron nitride-based multi-shell wave-absorbing anticorrosive coating, which specifically comprises the following steps: firstly preparing magnetic modified BN, then preparing a multi-shell m-BN-coated Fe-Co microsphere precursor, calcining the precursor, coating with modified nano TiO2, and finally preparing the wave-absorbing anticorrosive coating. The invention also discloses the coating prepared by the method. According to the invention, the high-density TiO2-coated wave-absorbing anticorrosive coating with a multi-layer Fe-Co doped carbon shell and a magnetic modified BN particle core can be obtained. The interaction between the BN particles and electromagnetic waves is enhanced through magnetic modification, a wave absorbing mechanism is increased through the multi-layer Fe-Co doped carbon shell, multiple scattering of the electromagnetic waves is achieved, and the wave absorbing efficiency is improved. The high-density coating of the modified nano TiO2 on the outer layer enhances the interface polarization and optimizes the wave-absorbing effect through the unique electronic structure of the modified nano TiO2. The design of the multi-shell m-BN-coated Fe-Co microspheres forms a multi-layer barrier, so that a corrosive medium is effectively blocked.

The invention belongs to the technical field of wave-absorbing materials, and particularly relates to a wave-absorbing material and a preparation method thereof, and a polyurethane composite wave-absorbing material and a preparation method thereof. The invention provides a wave-absorbing material. The wave-absorbing material comprises a carbon nano tube and selenide loaded on the carbon nano tube, the selenide comprises nickel selenide and cobalt selenide; a heterojunction structure is arranged between the nickel selenide and the cobalt selenide. According to the invention, a heterostructure is formed among selenide, and the structure can effectively enhance interface polarization of the material and promote an internal energy dissipation mechanism, so that electromagnetic waves are quickly converted into heat to be lost when passing through a heterointerface, and the electromagnetic wave absorption capability of the material can be optimized to a great extent; the wave-absorbing material not only can significantly improve the electromagnetic wave absorption performance, but also can maintain good environmental adaptability.

The application discloses a kind of high-entropy dual-phase sulfide and its preparation method and application, belong to electromagnetic wave absorbing material field.The application wants to solve how to enhance the weak interface polarization effect of high-entropy sulfide in electromagnetic attenuation problem.The application introduces Cu and Al metal elements into multi-metal sulfide by solvothermal and annealing method, and synthesizes a kind of six-component high-entropy sulfide wave-absorbing material (6-HES) with dual-phase structure, wherein all metal elements are uniformly distributed in M9S8 and MS (M represents metal element) two phases with crystal lattice defects.The high-entropy dual-phase sulfide prepared by the method has heterogeneous interface structure and rich vacancy defects, which not only can improve its conductance loss, but also can enhance defect-induced polarization and interface loss.The application taps the potential of multi-metal sulfide in the field of electromagnetic attenuation.

The invention belongs to the field of wave-absorbing materials, and particularly relates to three-dimensional oriented porous aerogel loaded with yttrium-cobalt nanoparticles as well as a preparation method and application of the three-dimensional oriented porous aerogel. According to the invention, electromagnetic waves are forced to repeatedly refract and scatter through the three-dimensional honeycomb-shaped directional pore channels to have a synergistic effect with multiple heterogeneous interfaces (carbon / Co, carbon / Y2O3 and Co / Y2O3), so that the material synchronously enhances interface polarization, dipole polarization and magnetic-dielectric loss, and efficient attenuation of the electromagnetic waves is realized; by forming an intermediate ZIF-67, highly uniform dispersion of cobalt on a molecular scale is realized, and a subsequent in-situ carbonization process is combined, so that highly dispersed and tightly embedded Co nanoparticles are successfully formed in a chitosan derived carbon skeleton, the interface bonding strength is remarkably improved, and agglomeration is inhibited; according to the process, biomass chitosan is used as a carbon source, and the process has the advantages of low filling, high performance and industrial compatibility. The aerogel-based wave-absorbing material disclosed by the invention has important application value in the fields of communication, aerospace and military protection.

The application provides a hetero-composite wave-absorbing material based on attapulgite, a preparation method and application thereof. The wave-absorbing material is prepared by acid activation and high-frequency ultrasonic stirring to disperse attapulgite in a deionized water system to form an attapulgite emulsion, and the well-dispersed attapulgite fibers are uniformly coated with a carbon layer on the surface through hydrothermal stirring and high-temperature carbonization; then, a flower-like NiCo2O4 is grown in situ on the carbon-coated attapulgite to construct a hetero-interface, the carbon-coated attapulgite is used as a dielectric loss material, the flower-like NiCo2O4 is used as a magnetic loss material, through hetero-structure design, the carbon layer can inhibit the skin effect caused by the cross-linked flower-like NiCo2O4, so as to amplify the magnetic response behavior of the NiCo2O4; the hetero-interface formed between the two can significantly enhance the interface polarization, realize impedance matching, significantly improve the microwave absorption performance, and overcome the defects of impedance mismatch and structure design existing in the prior art magnetic-dielectric synergistic wave-absorbing material.

The invention provides a micron rod-shaped Fe-Si-Al-based composite electromagnetic wave-absorbing material and a preparation method thereof, spherical FeSiAl alloy powder is subjected to ball milling to obtain micron rod-shaped powder, and the surface of the FeSiAl alloy powder is coated with TiO2 by utilizing hydrolysis reaction of tetrabutyl titanate, so that a FeSiAl-coated TiO2 core-shell composite electromagnetic wave-absorbing material is prepared; the FeSiAl-coated TiO2 core-shell composite electromagnetic wave-absorbing material is annealed in an argon or hydrogen-argon mixed gas atmosphere, the micron rod-shaped iron-silicon-aluminum-based composite electromagnetic wave-absorbing material is prepared, the shape anisotropy and the magnetic conductivity of FeSiAl are effectively improved, the oxygen vacancy concentration of TiO2 is regulated and controlled through annealing in a hydrogen-argon mixed gas reducing atmosphere, the polarization relaxation of dipoles is enhanced, and the electromagnetic wave-absorbing effect is improved. The core-shell structure enhances interface polarization, improves magnetic loss and dielectric loss, and effectively enhances the wave-absorbing bandwidth and reflection loss of the wave-absorbing material.

The invention discloses an iron-based nanoparticle and titanium dioxide magnetoelectric core-shell structure composite wave-absorbing material and a preparation method thereof, and belongs to the technical field of microwave absorbing materials. According to the preparation method, ferroferric oxide coated with titanium dioxide is taken as a precursor, and based on a confinement hydrogen reduction process, the relative content of a titanium dioxide shell layer and an iron and iron oxide composite core is changed by adjusting the dosage of tetrabutyl titanate, so that the construction and regulation of the magnetoelectric core-shell structure are realized. In the obtained composite wave-absorbing material, iron in the magnetic core can provide strong magnetic loss, iron oxide can improve impedance matching characteristics and introduce dielectric loss, and the titanium dioxide shell layer can enhance interface polarization and optimize impedance matching, so that the composite wave-absorbing material shows excellent low-thickness and broadband wave-absorbing characteristics. Meanwhile, the preparation process disclosed by the invention does not need large complex equipment, does not involve the use of highly toxic compounds, and has a relatively high popularization value.

The invention belongs to the technical field of electromagnetic wave absorbing materials, and relates to an Al-MOF-derived CAU-Al / rGO composite wave absorbing material and a preparation method thereof. The composite material takes a CAU-10-H (Al) MOF carbon-based derivative and reduced graphene oxide as main components, and is prepared through the processes of a solvothermal method, water bath heating, heat treatment, freeze drying and the like. The preparation method comprises the following steps: mixing graphite oxide powder and an ascorbic acid reducing agent according to a mass ratio, and carrying out stirring, cell crushing, a hydrothermal method and a vacuum freeze drying method so as to obtain reduced graphene oxide black powder; then, the CAU-10-H (Al) precursor is placed in a tubular furnace, and the CAU-Al (200) and the CAU-Al (300) are formed through heating and carbonization in the argon atmosphere; and finally, mixing the CAU-Al and the reduced graphene oxide powder according to a mass ratio, and uniformly stirring to obtain the composite wave-absorbing material. The carbonized MOF particles are doped in the reduced graphene oxide, so that the characteristic of light weight is realized, the dielectric loss capability, interface polarization and relaxation loss of the composite material are improved, the composite material has good impedance matching with air, and the electromagnetic wave absorption performance is remarkably enhanced.

The invention discloses a preparation method and application of a multi-layer carbon sphere material, a hollow carbon sphere is obtained by a hard template method, silicon dioxide is taken as a core, phenolic resin (RF) is taken as a shell, the silicon dioxide and the phenolic resin are repeatedly and alternately wrapped, and finally the multi-layer hollow carbon sphere can be obtained by carbonization and core removal. The multi-layer carbon spheres with different particle sizes can be obtained by adjusting the particle size of the silicon dioxide, and the layer number of the multi-layer hollow carbon spheres can be adjusted by adjusting the layer number covered by the phenolic resin. By means of reflection and scattering of the hollow structure of the hollow carbon sphere on electromagnetic waves and interface polarization among the multiple shell layers, the multilayer hollow carbon sphere has an excellent absorption effect on the electromagnetic waves. A novel preparation method is provided for the multilayer hollow carbon spheres, single-layer, double-layer and three-layer carbon spheres with different particle sizes are successfully prepared, the synthesis method is simple and convenient, the raw materials are low in price, and the obtained material has wide application prospects in the aspect of stealth technology.

The invention relates to the technical field of batteries, in particular to a positive plate and a preparation method thereof, a battery and electric equipment. The positive plate comprises a positive current collector and a positive active material layer arranged on one side of the positive current collector, the positive active material layer comprises a first active material layer and a second active material layer which are arranged in a stacked mode, the first active material layer is located between the second active material layer and the positive current collector, the first active material layer comprises LiMnx1Fey1PO4 and LiNia1Cob1Mc1O2, x1 + y1 = 1, a1 + b1 + c1 = 1, and the second active material layer is located between the first active material layer and the positive current collector. M comprises at least one of Mn, Al, Zr and Ti; the second active material layer comprises LiMnx2Fey2PO4 and LiNia2Cob2Mc2O2, x < 2 > + y < 2 > = 1, a < 2 > + b < 2 > + c < 2 > = 1, and M'comprises at least one of Mn, Al, Zr and Ti; the ratio of the mass content of Fe to the mass content of Co in the first active material layer is different from the ratio of the mass content of Fe to the mass content of Co in the second active material layer. According to the positive plate, micro-interface polarization can be improved, and the risk of local lithium precipitation caused by uneven charge distribution is reduced.

The present invention relates to the technical field of electromagnetic wave absorbing materials, in particular to a wave absorbing printing paste, a flexible and lightweight composite wave absorbing fabric and a preparation method and application thereof. By adopting a screen printing method, a graphene, MXene and Fe3O4 composite slurry is scraped on the surface of an aramid nonwoven fabric, and a soft and lightweight graphene@MXene@Fe3O4 composite wave absorbing fabric with antibacterial properties is prepared by a simple one-step method, wherein graphene provides dielectric loss, and MXene constructs a conductive network on the interlaced fibers to adjust impedance matching. At the same time, the magnetic material Fe3O4 is introduced to further improve impedance matching and increase magnetic loss. In addition, there are abundant interfaces between the above three materials and between the materials and the fabric, which will produce interface polarization, further enhance the wave absorbing performance, and are more green and environmentally friendly, easy to operate, and provide a new idea for the green industrial production of flexible wearable composite wave absorbing fabrics.

The application provides a method for calculating interface polarization charge and current distribution based on reflection coefficient, and relates to the technical field of computational electromagnetics. The method comprises the following steps: establishing a reflection coefficient-dielectric parameter mapping, directly correlating the reflection characteristics of electromagnetic waves with the intrinsic parameters of the medium through a reflection coefficient formula, and laying a physical foundation for polarization analysis; interface electromagnetic field reconstruction, using boundary conditions and constitutive relations to determine the electric field distribution on both sides of the interface and the corresponding polarization intensity. The distribution rule of the electromagnetic field in the medium is determined, the macroscopic electric field is converted into the spatial description of the polarization intensity, and an intermediate variable is provided for charge and current calculation; polarization dynamic response quantification, through the spatial and temporal derivatives of the polarization intensity, the interface polarization charge density and the polarization current density are derived. The theoretical model is converted into actual physical quantities, and the dynamic response mechanism of charges and currents when electromagnetic waves interact with the medium is revealed.

The invention provides a fiber woven structure dielectric film for a high-energy-storage-density capacitor and a preparation method, and aims to solve the problem that the dielectric constant and the breakdown strength of a polymer-based dielectric material are difficult to improve at the same time, so that the energy storage density cannot meet the requirements of a high-power-density energy storage capacitor. Polyetherimide / polyvinylidene fluoride-hexafluoropropylene core-shell structure fiber with a core-shell structure is prepared through a coaxial electrostatic spinning technology, a composite film is formed through lamination and hot pressing, a woven structure is regulated and controlled by adjusting the composition content of the core-shell fiber, the fiber orientation stacking direction and the stacking layer number, the mechanical strength of the film is enhanced, a deep trap is formed to capture carriers, and the performance of the film is improved. And a high dielectric constant is maintained by utilizing interface polarization, and the energy density is comprehensively improved.

This invention provides a broadband high-temperature resistant ceramic-based microwave absorbing material and its preparation method, belonging to the technical field of microwave absorbing materials. The microwave absorbing material uses silicon carbide powder with a particle size of 100-500 nm as the matrix material. Silicon carbide is mixed with acetylene black and polycarbosilane solution and ball-milled to prepare ceramic slurries containing different concentrations of acetylene black. The ceramic slurries are then poured into a steel mold and vibrated on a vibration table. The sample surface is then smoothed and dried in a vacuum freeze dryer. The dried green sample is then subjected to high-temperature pyrolysis under vacuum and bonded to obtain a silicon carbide ceramic-based composite material. This invention utilizes a concentration gradient multilayer structure to effectively improve the impedance matching of the material. Simultaneously, by utilizing the multiple reflection and scattering effects of electromagnetic waves between silicon carbide and acetylene black, as well as the interfacial polarization loss between silicon carbide and black, broadband high absorption of electromagnetic waves can be achieved under high-temperature conditions.

The invention discloses a low-voltage polarizable magnetic dielectric microsphere, a preparation method thereof and application of the low-voltage polarizable magnetic dielectric microsphere to adsorption of PFASs, and relates to the technical field of environmental functional materials. The microsphere has a core-shell structure of a conductive magnetic core-dielectric shell, the core is composed of ferroferric oxide and a carbon material, and the shell is a sodium alginate gel layer. The preparation method comprises the following steps: calcining the iron-carbon composite material, mixing a sodium alginate solution, cross-linking calcium lactate / calcium chloride step by step and the like. The microspheres can be subjected to interface polarization under the external 0.2-2 V / cm low-voltage direct-current electric field, a strong local electric field is generated to enhance electrostatic adsorption, meanwhile, the mass transfer and adsorption process of PFASs is synergistically enhanced through electrophoresis and electroosmotic flow effects, the adsorption rate and capacity are remarkably improved, and rapid separation can be achieved through a magnetic field. The material and the method are suitable for efficiently and deeply removing anionic PFASs in wastewater, and have the advantages of low energy consumption, high efficiency, simplicity and convenience in operation and the like.

The present invention discloses an MgO-C nanochain, a preparation method thereof, and an application as a microwave absorbing material. The preparation is carried out using a horizontal tube furnace, and evaporation zones and reduction zones are respectively arranged at both ends of the furnace body. Mg(acac)2 is used as a precursor and placed in the evaporation zone, and a substrate for collecting products is placed in the reduction zone. An inert gas is used as a carrier gas and reaction atmosphere, and a vacuum pump system is used to maintain the internal pressure of the system for reaction, and the MgO-C nanochains are collected on the substrate. In the MgO-C nanochains of the present invention, nano-MgO particles are connected by carbon to form a three-dimensional framework. By virtue of this unique structure, microwave absorbing effects such as enhanced interfacial polarization and multiple scattering reflections are strengthened, the microwave absorbing performance is greatly improved, and the frequency band is broadened. It has good microwave absorption performance and has very good application prospects in the fields of stealth technology and electromagnetic shielding.