171 results about "Absorption bandwidth" patented technology

The invention belongs to the field of protective materials, and particularly relates to a 3D printing high-performance porous silicon carbide ceramic wave-absorbing material and a preparation method and application thereof. The extrusion type 3D printing technology is combined with the reaction sintering and impregnation technology, the complex structure forming and the high-performance wave absorbing effect are achieved, the material prepared through the method has excellent mechanical performance and wave absorbing performance at the same time (the bending strength is larger than 15 MPa, the reflection loss minimum value at the frequency band of 2-18 GHz is larger than-25 dB, and the absorption bandwidth is larger than 3 GHz), and the material has the good application prospect. The method is suitable for military stealth engineering and other fields.

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 an aerogel metamaterial capable of switching electromagnetic wave absorption and deflection reflection wave beam and a preparation method thereof, and the preparation method is characterized in that a metamaterial unit with a loose structure is arranged and comprises a first layer of rectangular pyramid, a second layer of quadrangular frustum pyramid, a third layer of quadrangular frustum pyramid and an internal pyramid cavity; the first layer of rectangular pyramid, the second layer of quadrangular frustum pyramid, the third layer of quadrangular frustum pyramid and the internal pyramid cavity are on the same center line; the bottom surface of the internal pyramid cavity is close to the bottom surface of the third-time quadrangular frustum pyramid, and the vertex of the internal pyramid cavity is close to the vertex of the first-layer quadrangular pyramid; the preparation method comprises the following steps: pouring mixed dispersion liquid containing conductive / magnetic functional components and cellulose microfibers into a mold manufactured according to a set structure, freezing, and then freeze-drying to obtain the metamaterial unit. The obtained aerogel metamaterial solves the problems that the effective absorption bandwidth of aerogel with adjustable electromagnetic wave absorption performance is difficult to substantially break through, and the aerogel cannot have both electromagnetic wave absorption performance and deflection reflection beam performance at the same time.

The invention provides a broadband absorption and transmission integrated frequency selective surface with a high selection characteristic, which comprises a first loss layer, a second loss layer and a frequency selection layer, and is characterized in that the first loss layer and the second loss layer realize a transmission band with the high selection characteristic and the broadband characteristic at the same time by using dual-order resonance; the second loss layer and the frequency selection layer are cascaded to realize the absorption and transmission integrated characteristic, and the first loss layer is used for improving the low-frequency and high-frequency wave absorption characteristics and expanding the wave absorption bandwidth. Under the combined action of the first loss layer, the second loss layer and the frequency selection layer, wave transmission within the frequency band of 7.72-11.89 GHz and wave absorption within the frequency band of 1.96-7.12 GHz and the frequency band of 12.95-17.33 GHz are achieved. The antenna has high selection characteristics and broadband characteristics, can effectively suppress interference of external electromagnetic waves of other frequency bands or electromagnetic waves of a frequency band close to a communication frequency band on communication, can reduce the radar cross section of a target, and facilitates target stealth.

The invention discloses a method for preparing wave-absorbing integrated SiC / Si3N4 composite ceramic with high strength and toughness in a short period. Silicon nitride, silicon carbide, a sintering aid and other powder are mixed and dispersed for a short time through high-strength mechanical vibration, and the high-strength and high-toughness wave-absorbing composite ceramic is prepared after direct sintering. According to the preparation process, the preparation steps of ball milling, drying, sieving and the like are avoided, the preparation process period of the SiC / Si3N4 composite ceramic can be shortened from 1 week to 1 day, and the labor intensity is reduced; according to the preparation process, an organic solvent and a grinding medium do not need to be introduced, and pollution to samples and the environment is avoided; more importantly, the preparation process can effectively disperse the nano-powder and the whiskers, avoids the damage of a grinding medium to the powder such as particles and the whiskers, and enhances the strength and toughness of the ceramic material. The bending strength of the prepared SiC / Si3N4 composite ceramic can reach up to 1007 MPa, the fracture toughness reaches 11.63 MPa.m < 1 / 2 >, the minimum reflection loss of electromagnetic waves is-27 dB, and the wave absorbing bandwidth is 2.28 GHz.

The invention discloses an ultra-wideband three-dimensional metamaterial wave absorber with large angular domain stability, which comprises M * N wave absorber units, and is characterized in that M is more than or equal to 10 rows, N is more than or equal to 10 columns, and each wave absorber unit sequentially comprises an upper-layer three-dimensional vertical resistive film patch cylindrical structure, a bottom square resistive film structure or a metal bottom plate II from top to bottom, a lower-layer three-dimensional vertical resistive film patch cylindrical structure and a lower-layer square resistive film patch cylindrical structure from top to bottom. And the cylindrical structure of the upper-layer three-dimensional vertical resistive film patch is adhered to the bottom square resistive film structure through optical cement or adhered to the metal bottom plate II. According to the invention, the effects of ultra-wide absorption bandwidth, large angular domain stability and polarization insensitivity can be realized.

The invention relates to the technical field of aerogel materials, in particular to a carbon-rich SiC-coated Si3N4 double-network aerogel and a preparation method thereof. The double-network aerogel comprises an inner framework and an outer framework, the inner framework is a SiC network, the outer framework is a Si3N4 network, the double-network aerogel is formed by interweaving the SiC network and the Si3N4 network, the SiC network and the Si3N4 network are rich in in-situ carbon, and the content of the in-situ carbon in the Si3N4 network is far smaller than that of the in-situ carbon in the SiC network. The aerogel disclosed by the invention successfully integrates multiple key properties, wherein high porosity and low thermal conductivity ensure excellent thermal insulation capability; the reflection loss reaches-60dB to the minimum, and the effective absorption bandwidth reaches 5GHz, so that the excellent broadband wave-absorbing performance is proved; the compressive strength of the material can reach 14 MPa or above, excellent mechanical reliability is shown, and an ideal solution is provided for electromagnetic protection and thermal management of high-end equipment.

The invention belongs to the field of electromagnetic wave absorbing materials, and particularly relates to a thin broadband composite wave absorber based on a frequency selective surface. According to the invention, the wave-transparent layer is added in the middle of the multi-layer magnetic material, the mindset of simply stacking the same type of materials in the traditional multi-layer wave-absorbing structure is broken, and the wave-transparent layer is introduced to change the original characteristic that the impedance gradually changes in sequence; meanwhile, a magnetic wave-absorbing material, a frequency selection surface and a medium matching layer are subjected to composite design, the frequency selection surface generates an electromagnetic coupling effect at high frequency, phase and impedance conversion of electromagnetic waves in a multi-layer structure is controlled, and efficient impedance matching and electromagnetic wave energy dissipation in a broadband are achieved through electromagnetic absorption and interference cancellation; and an excellent wave absorbing effect is achieved. The total thickness of the composite wave absorber ranges from 0.064 lambda to 0.1 lambda, the-10 dB absorption bandwidth ranges from 3.3 GHz to 18 GHz, and the relative bandwidth reaches 138%; and meanwhile, the wave absorber has a wide angular domain characteristic under oblique incidence, and a novel thin broadband composite wave absorber scheme is provided.

The application discloses a reconfigurable transparent wave absorber based on a miura fold, and relates to a transparent wave absorber. The application aims to solve the problems of a narrow variable absorption bandwidth, a small change amplitude and a small absorption angle of an existing reconfigurable wave absorber. The reconfigurable transparent wave absorber based on the miura fold is composed of a miura fold-shaped wave absorbing layer and a planar reflecting layer from top to bottom; or the reconfigurable transparent wave absorber based on the miura fold is a single miura fold-shaped wave absorbing layer.

The invention discloses a broadband strong-absorption microwave metamaterial design and preparation method based on impedance control, and belongs to the field of electromagnetic absorption metamaterials. The invention aims to solve the problem that a microwave absorption metamaterial is difficult to realize wide absorption bandwidth and strong absorption intensity at the same time. The method comprises the following steps of: 1, solving an impedance value range of a resistive film layer on the surface of the microwave absorption metamaterial; 2, further extracting the available value ranges of the equivalent resistance and the equivalent capacitance of the resistive film layer; 3, traversing value ranges of the equivalent resistance and the equivalent capacitance, and collecting phase information of electromagnetic waves reflected by the corresponding metamaterial; 4, calculating a reflected electromagnetic wave phase difference; 5, selecting two metamaterial units of which the difference between the average value of the absolute values of the phase differences and the pi is minimum in the target frequency band; and 6, forming a new metamaterial unit through chessboard type distribution and arrangement, and realizing the design of the broadband strong-absorption metamaterial through common regulation and control of amplitude and phase. The method has universality and can be used for efficiently designing other metamaterial microwave absorbers with target performance.

This invention relates to a method for preparing a broadband absorption hydrogel. The method comprises the following steps: S1, mixing solvent A (N,N-dimethylformamide or acetonitrile) with deionized water to obtain a mixed solvent; S2, adding polyethylene glycol methyl ether acrylate-480 and acryloylmorpholine to the solvent in S1 and dissolving them to obtain a mixed solution; S3, removing dissolved oxygen from the mixed solution in S2, sealing the container, and stirring under ice bath conditions; S4, adding potassium persulfate and N,N,N',N'-tetramethylethylenediamine to the mixed solution after stirring in S3, and sealing the container again; S5, completing the polymerization reaction in the container at 60 °C to obtain the hydrogel. Compared with the prior art, the hydrogel material provided by this invention has improved reflection loss intensity and effective absorption bandwidth performance, thus providing a new perspective for developing highly flexible and efficient electromagnetic wave absorbers.

The invention discloses a multifunctional broadband electromagnetic wave-absorbing composite material based on a bionic periodic unit and a multistage core-shell filler and a preparation method thereof.The multistage core-shell filler is used as a raw material, an impregnation technology is adopted, and the bionic periodic unit is impregnated by preparing high-loss paint and impedance matching paint with different concentrations; the electromagnetic wave-absorbing composite material is obtained. Accurate gradient distribution and better impedance matching of electromagnetic parameters in a three-dimensional space are achieved, the density is lower than 6 kg / m under the thickness of 15-20 mm, the plane compression strength is 2 MPa, and the effective absorption bandwidth (RLlt;-10 dB) covers 8-18 GHz. The invention solves the contradiction between the bandwidth, thickness, weight and single function of the traditional wave-absorbing material, and is suitable for the fields of advanced stealth equipment and electromagnetic protection. The material opens up a new direction for the development of electromagnetic wave-absorbing materials, and is expected to be widely applied to many fields such as national defense, communication, electronics and the like.

The invention discloses a Ni3Al-PPy composite wave-absorbing material as well as a preparation method and application thereof, and belongs to the technical field of electromagnetic wave-absorbing materials. The Ni3Al-PPy composite wave-absorbing material with a core-shell structure is successfully synthesized by combining a thermit reaction with a chemical oxidation polymerization method and hydrochloric acid modification. By regulating and controlling the addition amount of the pyrrole monomer in the range of 0.25-0.75 mL, the continuous regulation and control of the thickness of the PPy shell layer from 0.22 [mu] m to 0.31 [mu] m is realized. When the thickness of a PPy shell layer is 0.27 mu m and the matching thickness of the composite wave-absorbing material is 3.0 mm, the minimum reflection loss and absorptivity gt of-40.0 dB are obtained at 9.27 GHz; and when the matching thickness is 2.0 mm, the effective absorption bandwidth reaches 3.02 GHz. According to the invention, the effect of the shell layer thickness in regulating and controlling the performance of the wave-absorbing material with the core-shell structure is illustrated, and a feasible strategy is provided for designing a high-performance light-weight wave-absorbing material with adjustable electromagnetic parameters and enhanced durability.

The invention discloses a hollow cobalt-based microtube designed based on a skin depth theory and a preparation method and application thereof, relates to the technical field of electromagnetic wave absorbing materials, and aims to solve the problems that an existing microwave absorbing material is insufficient in low-frequency-band magnetic loss, high in filling ratio or large in thickness, so that the system load is too heavy; and the design of the electromagnetic wave absorption microtube structure is lack of theoretical guidance. According to the method, the skin depth of electromagnetic waves in a conductor is converted into a wall thickness design parameter, the Co / rGO composite layer is constructed on the surface of the carbon fiber by electrodeposition for 9.0 minutes at the temperature of 60 DEG C for the first time, then the wall thickness is accurately controlled through gradient heat treatment of 800 DEG C air oxidation and 500 DEG C Ar / H2 reduction, and matching with the skin depth of cobalt at the frequency point of 3 GHz is achieved. The material breaks through the low-frequency absorption limit under the ultralow filling ratio of 0.85 wt%:-37.89 dB minimum reflection loss is obtained at the S wave band when the thickness is 1.0 mm, and the effective absorption bandwidth reaches 5.4 GHz; and when the thickness is 3.0 mm, the bandwidth is expanded to 7.8 GHz to cover multiple frequency bands. And an innovative solution is provided for aerospace stealth equipment and high-frequency electronic equipment.

A method for preparing a MOF-based multiphase composite electromagnetic wave absorbing material is disclosed, which relates to the preparation method and application of electromagnetic wave absorbing materials. The purpose of this invention is to solve the problems of poor attenuation and narrow absorption bandwidth in ABO3-type perovskite electromagnetic wave absorbing materials prepared by existing methods. This invention is based on the metallic Fe in MIL-88A. 3+ Ions were successfully induced to form an oxide perovskite phase in MIL-88A via etching, resulting in a hierarchical hollow nanocomposite material. In this structure, the oxide perovskite, a typical spinel-type p-type semiconductor, is composited with the surrounding elemental Fe phase through an outer graphitized carbon shell. Utilizing the heterojunction effect with metal-semiconductor contacts, an excellent interfacial polarization process is generated, significantly enhancing the dielectric loss performance of the composite material. Simultaneously, by consuming excess Fe metal... 3+ Excellent electromagnetic wave absorption performance was obtained by adjusting the impedance matching of the composite material.

The invention discloses a method for preparing a high-performance wave-absorbing material by in-situ construction of a polar organic coating through cooperation of microwaves and AlCl3-NaCl molten salt, and relates to the technical field of new material synthesis. Cutting, cleaning and drying the waste carbon fiber reinforced resin-based composite material to obtain a clean composite material a; the preparation method comprises the following steps: weighing a composite material a and AlCl3-NaCl molten salt, enabling the AlCl3-NaCl molten salt to be in full contact with the composite material a, carrying out microwave molten salt in-situ pyrolysis in a microwave oven under the protection of a protective atmosphere, and realizing in-situ construction of a polar organic nano coating on the surface of the carbon fiber by utilizing microwave and AlCl3-NaCl molten salt catalysis treatment; and repeatedly washing with deionized water, and carrying out suction filtration and drying to obtain the organic coating / carbon fiber wave-absorbing composite material. When the thickness of the prepared organic coating / carbon fiber composite material is 1.4-4.0 mm, the reflection loss can reach-40.20--69.00 dB, the effective absorption bandwidth is 2.2-4.05 GHz, and the organic coating / carbon fiber composite material has light and thin characteristics and excellent electromagnetic wave absorption, is excellent in electromagnetic wave absorption performance and has a relatively good application prospect.

This invention belongs to the field of microwave absorbing materials technology, and discloses a SiBCN-ZrO2 ceramic composite material with high temperature resistance, oxidation resistance, and full X-band absorption, as well as its preparation method. First, SiBCN and ZrO2 polymer liquid-phase precursors are uniformly mixed, followed by low-temperature curing and high-temperature pyrolysis heat treatment, ultimately obtaining a SiBCN-ZrO2 ceramic composite material with ZrO2 uniformly distributed in an amorphous SiBCN matrix. This ceramic composite material has an effective absorption bandwidth of 4.2 GHz in the X-band, compared to 3.65 GHz for pure PDC-SiBCN ceramic, demonstrating an improved effective absorption bandwidth that covers the entire X-band, and also improving oxidation resistance. The preparation process of the SiBCN-ZrO2 ceramic composite material prepared by this invention is simple and can effectively improve the insufficient dielectric loss capacity of PDC-SiBCN ceramic as a microwave absorbing material, enhancing the overall high-temperature resistance and oxidation resistance of the material.

The invention discloses a cubic ZIF-67 / MXene wave-absorbing material as well as a preparation method and application of the cubic ZIF-67 / MXene wave-absorbing material. The preparation method comprises the following steps: reacting lithium fluoride, concentrated hydrochloric acid and deionized water to generate hydrofluoric acid, and etching an MAX phase to obtain MXene; the preparation method comprises the following steps: dispersing CoCl2. 6H2O, cetyl trimethyl ammonium bromide (CTAB) and MXene in deionized water to form a solution A; dispersing 2-methylimidazole in deionized water to form a solution B; quickly pouring the solution A into the solution B, stirring and reacting, centrifuging, freeze-drying and annealing to obtain the cubic ZIF-67 / MXene wave-absorbing material. The material is of a multi-layer sandwich structure, the reflection loss at 16.69 GHz can reach-20.79 dB, the matching thickness is 1.87 mm, the effective absorption bandwidth (RL is smaller than or equal to-10 dB) is 6.19 GHz (11.81-18.00 GHz), and the Ku wave band is covered. The method is environment-friendly in process, low in cost, simple and convenient to operate and suitable for large-scale production, and has application prospects in the fields of microwave absorption, infrared stealth and photocatalysis.

This application provides a filler for an encapsulation material and its preparation method, a magnetic molding compound, and an encapsulation device. The filler for the encapsulation material includes ferrite particles, wherein the ferrite particles include nickel-copper-zinc ferrite (Ni... a Zn b Cu c Fe d The O4 material has the following properties: a ranges from 0.3 to 0.55, b ranges from 0.45 to 0.55, c ranges from 0 to 0.2, and d ranges from 1.8 to 2. The ferrite particles have a particle size of 2-11 μm, accounting for 50-70% of the total. This filler has advantages such as low relative density, wide absorption bandwidth, and good high and low temperature performance, thereby reducing the overall weight of the packaged device and improving its electromagnetic interference resistance and applicable temperature range.

This application discloses a broadband sound absorption structure for an air conditioner compressor, comprising: a carrier; multiple sound-absorbing units arranged in a matrix on the carrier; each sound-absorbing unit having multiple sound-absorbing cavities spaced apart and sound-absorbing holes formed on the surface of each sound-absorbing cavity; multiple sound-absorbing holes of the same sound-absorbing unit being on the same horizontal line and the hole size gradually increasing from one side to the other; and the hole wall of each sound-absorbing hole extending towards the sound-absorbing cavity; through the matrix arrangement of sound-absorbing units and their hole size gradient design, a multi-band Helmholtz resonant cavity is formed, utilizing the resonant frequency difference corresponding to different hole sizes to cover broadband sound absorption requirements from low frequency (80Hz) to high frequency (8000Hz); at the same time, the regular matrix arrangement enhances the sound wave scattering effect, increasing the sound absorption bandwidth by about 60% compared to traditional structures.

The invention discloses an adjustable ultra-wideband terahertz metamaterial wave absorber, and belongs to the technical field of terahertz wave absorbers. The wave absorber is composed of a plurality of same metamaterial structure units which are periodically arranged, and each metamaterial structure unit is made of three layers of composite materials, wherein the first layer is a graphene pattern layer, the second layer is a polyimide dielectric layer, and the third layer is a copper reflecting layer. Wherein the graphene pattern layer adopts a combined design of four groups of square and L-shaped structures, and the four groups of structures form a biaxial symmetry layout through geometric coupling. The structure has the characteristics of wide absorption bandwidth, high absorption rate and dynamic adjustability, can realize more than 90% of efficient absorption in the frequency band of 2.28-4.68 THz, and can adjust the Fermi level of the graphene by externally applying bias voltage to realize rapid switching between the absorption state and the reflection state. The device is suitable for various application scenes such as terahertz communication, sensing and stealth.

The present application relates to wave-absorbing material technical field, specifically to a kind of nitrogen-doped carbon / cobalt-based wave-absorbing agent and its preparation method and application.The specific preparation method includes the following steps: with nitrogen-doped carbon nanosheet as matrix, 2-methyl imidazole as organic ligand, under solvent system, with Co source is co-precipitated, make the ZIF-67 formed on nitrogen-doped carbon nanosheet, then under protective atmosphere, at 700 DEG C~900 DEG C pyrolysis, obtain nitrogen-doped carbon / cobalt-based wave-absorbing agent.The carbon nanosheet stable structure of preparation supported cubic ZIF-67, so that the Co / NCS composite material after pyrolysis exists heterostructure interface, strengthens multiple loss mechanism.The wave-absorbing agent can be used to prepare electromagnetic wave absorbing material, under lower filling amount, higher reflection loss and wider effective absorption bandwidth are realized.The existing wave-absorbing material exists the problem of narrow effective absorption bandwidth and weak electromagnetic wave loss capacity.

The present invention discloses a four-function terahertz metasurface absorber with dual electrical / thermal control and a preparation method thereof. The absorber utilizes a novel structural design of graphene layers and vanadium dioxide layers. The surface comprises an outer square graphene ring, four graphene trapezoids, and an inner square graphene structure, effectively increasing the absorption bandwidth. The absorber also utilizes a dual-control design of graphene voltage and vanadium dioxide temperature. By independently regulating the voltages of the inner and outer graphene patterns, switching between a single-frequency absorption mode and a broadband absorption mode is achieved. Adjusting the temperature of the vanadium dioxide layer allows the absorber to switch between a low-frequency absorption band and a high-frequency absorption band, making the absorber a four-function terahertz metasurface absorber with dual electrical / thermal control. The present invention effectively addresses the current problem of absorbers being unable to regulate absorption bands and absorption modes, opening up a new path for device design in the field of terahertz absorption.

The application relates to a ZrB2 / ZrC composite ceramic wave-absorbing material and a preparation method thereof, and belongs to the field of wave-absorbing materials. The material comprises ZrB2 and ZrC; the ZrB2 is connected with each other to form a space net structure; and the outer wall of the ZrB2 is coated with granular ZrC crystals to form a rough surface. The method is characterized in that ZrB2 is prepared by using a polymer conversion method; ZrC liquid-phase precursors are impregnated into the polymer conversion ZrB2 as a matrix; after sufficient impregnation, solidification is carried out; and after the solidified sample is heat treated, the polymer conversion ZrB2 / ZrC composite material is obtained. The ZrB2 / ZrC ceramic wave-absorbing material prepared by the application has a minimum reflection loss of -64.64 dB, and an effective absorption bandwidth of 6.94 GHz when the material thickness is 4.33 mm.

The invention discloses a preparation method of light high-strength super-hydrophobic carbon foam / SiO2 composite aerogel and application of the light high-strength super-hydrophobic carbon foam / SiO2 composite aerogel in icing prevention / microwave absorption. The preparation method comprises the following steps: by taking foamy carbon as a structural reinforcement, completely impregnating SiO2 sol into pores of the foamy carbon through vacuum impregnation, and then carrying out gelation, aging, replacement and normal-pressure drying to construct the light high-strength super-hydrophobic carbon foam SiO2 composite aerogel with the interpenetrating phase structure. The material has excellent compressive strength, anti-icing performance (21s rapid deicing performance under low voltage of 2V and ultra-long anti-icing time) and electromagnetic wave absorption characteristic, and dual-interface polarization formed by foamy carbon and SiO2 aerogel enables the minimum reflection loss of the composite aerogel to reach-22.6 dB and the absorption bandwidth to reach 4.48 GHz. The composite aerogel maintains the original structure and contact angle after multiple times of mechanical wear, the water contact angle is as high as 158.3 degrees, and the rolling angle is as low as 4.9 degrees.

The invention relates to the technical field of wave-absorbing materials, in particular to a SiBCN-Fe ceramic corrosion-resistant wave-absorbing material and a preparation method and application thereof. The preparation method comprises the following steps: preparing a hyperbranched PBSZ-SiH polymer in an argon atmosphere; under the protection of argon, ferric acetylacetonate is dissolved in anhydrous xylene, and then the hyperbranched PBSZ-SiH polymer is added for a reaction; collecting a solid phase to obtain a PBSZ-Fe ceramic precursor; heating the PBSZ-Fe ceramic precursor, and carrying out a cross-linking reaction; and grinding a product obtained after the cross-linking reaction into powder, and then performing high-temperature pyrolysis in an argon atmosphere to obtain the SiBCN-Fe ceramic. According to the SiBCN-Fe ceramic corrosion-resistant wave-absorbing material, in a 3.5 wt% NaCl / H2O solution, the corrosion potential (Ev) is 0.035 V, the corrosion current density (Icorr) is 6.295 * 10 <-7 > Acm <-2 >, and the SiBCN-Fe ceramic corrosion-resistant wave-absorbing material is superior to most corrosion-resistant wave-absorbing materials; the effective absorption bandwidth (EAB) of 8.16 GHz under 2.7 mm and the minimum reflection loss of-32.2 dB under 2 mm are achieved, and excellent corrosion resistance and excellent wave absorbing performance are achieved.

The invention discloses a vanadium dioxide-based terahertz broadband chiral absorber capable of being actively regulated and controlled, and belongs to the technical field of terahertz metamaterial design. The problems that an existing chiral terahertz absorber is narrow in absorption bandwidth and single in light absorption function are solved. The terahertz broadband chiral absorber sequentially comprises a reflection bottom layer, an intermediate dielectric layer and a top layer from bottom to top; the top layer is formed by arranging a plurality of structural units in an array; each structural unit is composed of a Z-shaped gold structure and four vanadium dioxide micron plates; the four vanadium dioxide micron discs are symmetrically arranged on the left side and the right side of the middle longitudinal arm respectively and attached to the edges of the left side and the right side of the middle longitudinal arm. The invention is used for the vanadium dioxide-based terahertz broadband chiral absorber capable of being actively regulated and controlled.

The application discloses a tunable bidirectional metamaterial light absorption device and an optimization and preparation method thereof, and relates to the technical field of metamaterial optical absorption devices; the bidirectional absorption device is a six-layer structure of metal-dielectric-metal-dielectric-metal-dielectric, and the device units thereof are sequentially a silver metal layer, a liquid crystal dielectric layer, a silver metal layer, a liquid crystal dielectric layer, a chromium metal layer and a silicon nitride ring from bottom to top; the bidirectional light absorption device can realize wideband absorption on top incident plane light and narrowband absorption on bottom incident plane light in a wavelength range of 0.6-1.6 microns. By changing the liquid crystal molecule deflection angle in the liquid crystal dielectric layer, the absorption rate and the absorption bandwidth range of the device on the top or bottom incident light can be adjusted and controlled, so that tunability is realized. The application can realize the structural parameter optimization design of the device under multiple target constraints.

This invention discloses a magnetic amorphous carbon composite aerogel fiber, its preparation method, and its applications, belonging to the field of electromagnetic functional materials. The aerogel fiber has a continuous fiber morphology, composed of an amorphous carbon three-dimensional network framework and uniformly embedded MOF-derived magnetic nanoparticles. The core of its preparation method involves blending transition metal MOF nanoparticles with aramid nanofiber dossile, wet spinning through a unique "MOF-induced-protonation" synergistic gelation mechanism, followed by high-temperature carbonization, which transforms the MOF into magnetic particles in situ and anchors them within the carbon framework. This method is highly versatile and applicable to various MOFs such as Fe, Co, Ni, and Mn, and is simple and can be continuously produced. The resulting aerogel fiber possesses ultra-low density, high flexibility, and excellent broadband strong absorption performance (effective absorption bandwidth ≥ 7.0 GHz, reflection loss ≤ -50 dB), showing broad application prospects in wearable electronics, aerospace stealth, and 5G communication electromagnetic protection.

The invention belongs to the technical field of aerogel wave-absorbing materials, and particularly relates to trimetal MOFs / MXene derived aerogel as well as a preparation method and application thereof. According to the preparation method, Ni (NO3) 2.6 H2O, Co (NO3) 2.6 H2O and Cu (NO3) 2.3 H2O are used as metal sources, water-induced self-assembly, freeze drying and heat treatment are performed to prepare the aerogel, and the aerogel is of a 0D / 1D / 2D composite structure and contains nano twin crystals. The MXene content and the filler content are regulated and controlled to optimize the performance, the minimum reflection loss of the optimal sample NiCoCu / MX5-A reaches-83.73 dB, and the effective absorption bandwidth is 6.46 GHz. The aerogel has the advantages of light weight (9.2 mg.cm <-3 >), heat insulation, 82.93% photothermal conversion efficiency, 102.4 kPa compressive strength and hydrophobic property, is suitable for the fields of electromagnetic protection and the like, and provides support for design of multi-element aerogel-based wave-absorbing materials.