884 results about "Wave absorption" patented technology

The invention provides a preparation method of novel core-shell type cement-based high-strength lightweight aggregate. A cement-based composite material (cement and an admixture) is used as a main cementing material of a shell material, a pelletizing process is adopted for surrounding a shell outside a lightweight core material, and the high-strength lightweight aggregate can be successfully prepared after curing is performed for a certain period of time. The prepared light aggregate has the advantages of high specific strength, good grain shape and good heat preservation and heat insulation, and can realize certain specific functions, such as heat storage, sound insulation and wave absorption. A production process of the high-strength light aggregate comprises the steps of mixing powder, uniformly stirring, spraying liquid to form pellets, curing (steam curing and moisturizing) and screening. According to the preparation method, the problems of great production energy consumption, complex process and serious pollution of the aggregate produced by a traditional sintering process or the problems of relatively large packing density, insufficiently high strength and insufficiently high product quality of unburned ceramsite products are solved.

The invention discloses a novel infrared and radar integrated stealth fabric and a preparation method thereof. The stealth fabric comprises an infrared camouflage surface layer and an antistatic bottom layer in turn from outside to inside; the infrared camouflage surface layer comprises an infrared stealth layer, a fabric layer and a radar wave absorption attenuation layer in turn from outside toinside; the infrared stealth layer is compounded by using a coating coated by an infrared stealth coating and a magnetron sputtering ITO (indium tin oxide) film arranged on the surface of the coating; the radar wave absorption attenuation layer comprises a sponge body; and a wave absorption material is adsorbed on the sponge body. The stealth fabric can realize radar stealth function and infraredstealth function at the same time, has good integral wave absorption effect and low surface density of materials, and has good effects on the aspects of breaking strength, bursting strength and the like. Moreover, excessive complex processes are not adopted for manufacturing the stealth fabric, and the stealth fabric can be produced by using a conventional fabric production method, so the stealthfabric is convenient for production and easy for implementation.

The present invention belongs to the field of radiation resisting technology, and is especially one kind of nanometer wave absorbing fiber. The nanometer wave absorbing fiber consists of nanometer wave absorbing particle of 1-100 nm diameter of fine fiber of 30-2000 nm diameter in the weight ratio of 3-35 to 65-97. The nanometer wave absorbing fiber has wide wave absorbing range, powerful wave absorbing capacity, lasting wave absorbing effect and high flexibility. It has wave absorbing function, as well as antistatic, bacteriostasis, biochemical protection and other functions.

The invention discloses a radar wave stealth coating with good radar wave-absorbing performance, light mass and thermal insulation function, and a production method thereof. The coating comprises a film-forming substance, an absorbent, an external additive and a solvent. The coating is characterized in that the radar wave absorbent is hollow microspheres covered with magnetic conductive metal films. The coating absorbent has good performance, light mass and good thermal insulation. The components by weight percentage comprise the following: 16.25 to 74.40 percent of film forming substance, 25.60 to 83.80 percent of absorbent, 1 to 20 percent of additive, and 10 to 150 percent of solvent. The coating is applied to the field of radar wave absorption, for example, the coating is used for various weapons, camouflage nets and, protection suits and so on.

The invention relates to wave absorption concrete and a preparation method thereof. High-iron ground steel slag lightweight high-toughness wave absorption concrete is characterized in that the concrete is prepared from powder, aggregate and admixture, wherein the powder consists of silicate cement, fly ash and high-iron ground steel slag; the aggregate is ceramic sand; the admixture consists of efficient water reducing agent, basalt fiber and water; and the concrete comprises the following raw materials in a ratio (kg/m<3>): 110 to 300 kg/m<3> of silicate cement, 80 to 120 kg/m<3> of fly ash, 70 to 140 kg/m<3> of high-iron ground steel slag, 600 to 1,500 kg/m<3> of ceramic sand, 3.0 to 4.5 kg/m<3> of efficient water reducing agent, 30 to 50 kg/m<3> of basalt fiber and 150 to 180 kg/m<3> of water. The wave absorption concrete has the characteristics of energy conservation, environmental protection and low price.

The invention relates to a broadband wave absorption composite material with a multilayer structure and a preparation method thereof. The broadband wave absorption composite material is characterized in that the material comprises three parts, namely a surface layer, a sandwich layer and a bottom layer; the surface layer comprises, by mass percentage, 20 to 50 percent of carbonyl iron dust, 30 to 48 percent of polymer and 20 to 32 percent of fiberglass cloth; the sandwich layer comprises, by mass percentage, 2 to 6 percent of carbon nanometer tube, 56.4 to 58.8 percent of polymer and 37.6 to 39.2 percent of fiberglass cloth; and the bottom layer comprises, by mass percentage, 50 to 80 percent of carbonyl iron dust, 12 to 30 percent of polymer and 8 to 20 percent of fiberglass cloth. The broadband wave absorption composite material has the advantages of low surface density, thin thickness and high mechanical strength, and improves the bearing performance and the engineering application value.

The invention relates to a preparation method of a carbon-cladding Fe3O4 microsphere wave-absorbing material, and relates to a preparation method of a wave-absorbing material. The preparation method aims to solve the problem of poor electromagnet wave absorption because impedance match is difficult to realize due to lower dielectric constant of Fe3O4 at present. The method comprises the following steps of: 1, preparing a Fe3O4 microsphere; 2, preparing a phenolic resin-cladding Fe3O4 microsphere; 3, preparing a carbon-cladding Fe3O4 microsphere. The carbon and Fe3O4 core-shell structure wave-absorbing material prepared through the method disclosed by the invention achieves the real part of a dielectric constant more than 18 and the imaginary part of the dielectric constant mainly about 0 at low frequency, thereby being favorable to realizing the impedance match and enhancing the wave-absorbing property; the carbon and Fe3O4 core-shell structure composite material prepared through the method disclosed by the invention can be used for the field of electromagnet wave absorption.

The invention discloses a structural material for the modulation of terahertz waves, which belongs to the technical field of electronics. The structural material comprises a medium substrate (2) and a vibratron array (1) attached to the surface of the medium substrate (2), wherein the medium substrate (2) is the medium material substrate highly transparent to the terahertz waves; the vibratron array (1) consists of a plurality of vibratron units with the same shape and size; and each vibratron unit is formed by a vanadium dioxide thin film on deposited on the surface of the medium substrate (2). The structural material adopts a medium material highly transparent to the terahertz waves as the substrate to achieve little and stable terahertz wave absorption loss, adopts the vanadium dioxide thin film which is a high-speed phase change material to manufacture the vibratron array, realizes the modulation of the terahertz waves by triggering the phase change of the vanadium dioxide thin film by thermal or laser modulation, and compared with a conventional metal vibratron array-based terahertz modulator, has greater modulation depth.

The invention discloses a heat preventing and insulating stealth compound material with broad-band wave absorption and a preparation method thereof. The compound material comprises a cold-faced panel,a first aerogel compound material heat-insulating layer, a first resistance high-temperature super-material layer, a second aerogel compound material heat-insulating layer, a second resistance high-temperature super-material layer, a third aerogel compound material heat-insulating layer and a hot-faced panel from inside to outside sequentially. In the aspect of heat preventing and insulating performance, compared with existing heat insulating tiles and cover plate type heat prevention systems, the integrated heat preventing and insulating stealth compound material has the advantages of good heat insulating performance, excellent mechanical performance, large component preparation availability, high reliability, easiness in maintenance and the like; and in the aspect of stealth performance, the technical scheme adopting the high temperature super-material has the advantages of strong designability and easiness in broad-band wave absorption implementation, weight gain is hardly generated in comparison with the technical scheme of a cold-faced by adopting a wave absorbing material, absorbent is not required to be added into a heat preventing and insulating material, the heat preventing and insulating performance is not influenced, and the material has good uniformity and strong controllability.

The invention relates to a wide-angle polarization-insensitive low RCS (Radar Cross Section) meta-material wave absorber. The wide-angle polarization-insensitive low RCS meta-material wave absorber is applied to great reduction of a target echo, thereby achieving the stealth characteristic of a target. A basic unit of the wave absorber consists of four double-opening resonant rings which are rotationally symmetric, the transmission number of a meta-material unit in a working band is 0, the minimum reflection coefficient is minus 18.75dB, the maximum wave absorption rate is 98.9 percent, and a perfect wave absorbing effect is achieved. The TE and TM polarization incident wave within a range of minus 60 degrees to 60 degrees can be absorbed, the maximum decrement of an RCS in the working band can reach 12.35dB, and the effective stealth of the radar target is achieved.

The invention discloses a flexible electromagnetic wave shielding and absorbing cloth and a production method thereof. The flexible electromagnetic wave shielding and absorbing cloth comprises a four-layer structure which sequentially comprises a chemical fiber fabric layer, an electromagnetic wave shielding layer, an electromagnetic wave absorbing layer and a flame-retardant and waterproof layer from bottom to top. The production method of the flexible electromagnetic wave shielding and absorbing cloth comprises the following steps: 1, drying the chemical fiber fabric; 2, preprocessing the chemical fiber fabric obtained in step 1; 3, plating the chemical fiber fabric obtained in step 2 with a layer of meta; 4, coating the metal layer plated chemical fiber fabric obtained in step 3 with a layer of a wave absorbing coating; and 5, coating the wave absorbing layer coated chemical fiber fabric obtained in step 4 with a layer of a flame-retardant and waterproof coating. The electromagnetic wave shielding and absorbing cloth has the advantages of wide wave absorption frequency band, high absorption intensity, flame retardation and waterproofing property, good flexibility, light weight and thin thickness, and can be applied to electromagnetic interference and electron strike prevention in the fields of electronic products and military devices.

The invention discloses a composite material with electromagnetic shielding and radar wave absorption functions, which comprises: 0.05~20 nano carbon tube, 40~99.9 polymer, and 0.05~40 coupling agent. The product is fit to different plate and tube material with same function. This invention also discloses two preparation methods.

The invention discloses a low-pass and high-absorption electromagnetic functional layer, which comprises a low-pass and high-resistance frequency selection surface and a wave absorption unit array, wherein the low-pass and high-resistance frequency selection surface comprises metal structure unit arrays which are etched on two surfaces of a dielectric substrate and are different in structure size; the periods p of the unit arrays are 10.0mm to 20.0mm; metal structure units have rotation symmetry; the frequency selection characteristics of the metal structure units are irrelevant to the polarized direction of an incident wave; the metal structure units on two surfaces are different in size; the wave absorption unit array is a periodic array which comprises square or round sheets which are fabricated by magnetic loss radar wave-absorbing materials or resistance type wave-absorbing materials; the wave absorption unit array has broadband wave absorption performance on a high-frequency band; the sizes of wave absorption units are smaller than those of the metal structure units; and each wave absorption unit is adhered to one side of each metal structure unit with a relatively small size of the low-pass and high-resistance frequency selection surface. The obtained material is small in insertion loss, small in thickness, flexible in design and low in cost.

The invention discloses a composite material of sub-group metals compounded with MXenes and a preparation method of the composite material. The composite material of sub-group metals compounded with MXenes is prepared from MXenes materials and sub-group metals, wherein the surfaces of the MXenes materials are coated with the sub-group metals in situ, and the sub-group metals are also distributed among layers of the MXenes materials. The preparation method comprises the following steps: grinding precursor Mn+1AXn-phase materials, sub-group metal salts and inorganic salts for 5-60min by adoptinga molten salt method, enabling the obtained mixture to react for 1-48h at 300-800 DEG C in inert atmosphere, and then, performing post-treatment to obtain the composite material of the sub-group metals compounded with the MXenes. The composite material disclosed by the invention has the advantages of adjustable and uniform components, low cost, environmental protection, high efficiency and the like, and has application prospects in the fields of electrode materials for electrochemical energy storage, wave absorption materials, electromagnetic shielding materials, catalysts and the like.

The invention belongs to the design and preparation technology of porous amorphous alloy materials, in particular to an aluminum-based micro/nano-meter porous amorphous alloy material and a preparation method thereof. The invention mainly solves the problems of low compressed plastic deformation of an aluminum-based amorphous alloy material, low strength and low corrosion resistance of foam metalaluminum, scarcity of aluminum-based micro/nano-meter porous amorphous alloy materials, nanometer aperture of porous materials, and the like. The preparation method comprises: firstly, quickly solidifying aluminum-based alloy melt under a condition of quick cooling to obtain an aluminum-based amorphous alloy material composite material containing micro/nano scale crystalline grains; secondly, subjecting the amorphous composite material to electrochemical corrosion or chemical treatment to obtain the aluminum-based micro/nano-meter porous amorphous alloy material. The aperture of the aluminum-based micro/nano-meter porous amorphous alloy material ranges from 1 nano meter to 100 microns, and the porosity of the aluminum-based micro/nano-meter porous amorphous alloy material is 1 to 50 percent. The geometrical form of the aluminum-based micro/nano-meter porous amorphous alloy material is determined by a required material form. And the geometrical form of the aluminum-based micro/nano-meter porous amorphous alloy material can be used as a material for wave absorption, vibration and noise reduction, sound absorption, electromagnetic shielding, catalytic absorption, energy-absorption buffering and the like.

The invention provides a preparation method of a wave absorbing material with nickel nanoparticles wrapped with porous carbon-loaded graphene. The preparation method of the wave absorbing material with the nickel nanoparticles wrapped with the porous carbon-loaded graphene comprises the steps that alga are used as a carbon source and soaked in a nickel saline solution, and nickel ions are made to enter algal cells; low-temperature heat treatment is conducted on the alga after the alga are frozen and dried, so that the alga are converted into carbon, and metallic nickel slat is oxidized into nickel oxide; and then the temperature is increased to continue to conduct high-temperature heat treatment, so that the nickel oxide is reduced into nickel, the amorphous carbon wrapping the nickel nanoparticles is catalyzed and graphitized in the heat treatment process, and finally the composite material with the nickel nanoparticles wrapped with the porous carbon-loaded graphene is obtained. According to the preparation method of the wave absorbing material with the nickel nanoparticles wrapped with the porous carbon-loaded graphene, the alga are used as the carbon source, and thus the preparation method is economical and practical; nickel is evenly dispersed onto a carbon material by means of the characteristic that holes of natural algal plants are abundant; a porous carbon material of a network structure is obtained after heat treatment, the nickel particles wrapped with the graphene are dispersed on the surface of the porous carbon material, and thus the material has excellent micro-wave absorption performance.

The invention relates to a judgment method for detecting defects of a wave absorption coating by using pulse infrared thermal waves and belongs to the technical field of nondestructive inspection. According to the judgment method, heating equipment for stimulating a test piece to be detected can be a high-energy flash lamp or other pulse type heating equipment; a high-energy flash lamp or other pulse type heating equipment with relatively short pulse acting time is suitable for being adopted; the collection frequency of a thermal imaging device is relatively high and the collection time is set according to the specific property of a material of the test piece to be detected. According to the judgment method, firstly, a standard test piece with a common defect type needs to be selected to be subjected to an experiment; thermal diffusion characteristics are extracted and defect judgment criteria are established to realize the judgment on different defect types; when the structure of the coating is changed, such as a coating material and a coating thickness, reconstructed unstuck defect criteria need to be referred.

The invention provides a ferrite material and MXenes composite material. Ferrite molecules are dispersed in a lamellar structure of MXenes. The ferrite material and MXenes composite material has good electrical conductivity, and accordingly, even when the temperature is lower than 260K, the ferrite material and MXenes composite material can still keep a certain electrical conductivity; the ferrite material and MXenes composite material good in impedance matching performance can be applied to various electronic parts and components such as anti-electromagnetic interference antennae, filters and inductance components by serving as a wave-absorbing material and is particularly applicable to wave absorption at low temperatures.

The invention relates to a full electric wave darkroom possessing both aerial radio frequency testing and EMC testing abilities, belonging to the technical field of aerial radio frequency testing darkroom and full electric wave darkroom design for radio equipment. And it comprises shielding casing, wave absorption material layer bonded with inner wall of the casing, false wall, darkroom door, turntable and tested equipment supporting device installed in the casing, antenna bracket system, vent illuminating device, filter, safe and electrical device and interface board to be connected with a tester, where the shielding casing is L-shaped, on two sides of the L shape are OTA testing darkroom and full electric wave darkroom, mutually vertical and interconnected, and a set of turntable and tested equipment supporting device is arranged at the junction of the two darkrooms. And it can reduce darkroom construction cost and raise utilization ratio.

The invention provides a preparation method for graphene-containing nanopaper. The preparation method comprises the following steps of: taking 30g of natural crystalline flake graphite with particle diameter of less than or equal to 45 mum as a raw material; uniformly mixing 30ml of H2SO4, 10g of K2S2O8 and 10g of P2O5 and then filling in a flask; heating to 80 DEG C; then adding 20g of dried natural flake graphite with particle diameter of less than or equal to 45 mum into the flask; heating to 80 DEG C to perform oxidation reaction; oxidizing the graphite by using a humers method to obtain oxidized graphite; mixing the graphite and carbon nanofiber in mass fraction ratio of 1:2; pressurizing suspension to obtain a wet thin film; and drying to obtain dry and complete nanopaper. The conductivity of the nanopaper is about three times improved than that of the original normal nanopaper; the loss rate of the nanopaper material can be increased due to the addition of the graphene; the maximum loss of the pure carbon nanofiber nanopaper is 94.1 percent, and the wave absorption peak value reaches 12dB; and the maximum loss rate of the nanopaper after the addition of the graphene is 96.5 percent, and the wave absorption peak value reaches 13dB.

The invention provides an artificial super-surface electromagnetic wave amplitude modulator based on graphene, and mainly solves the problems of small modulation scope and narrow modulation bandwidth of a conventional electromagnetic wave amplitude modulator. The artificial super-surface electromagnetic wave amplitude modulator comprises a DC power supply and a frequency selection surface, three layers of dielectric substrates and a reflecting plate laminated from top to bottom sequentially, wherein a dielectric layer with relative dielectric constant less than three is arranged between the second dielectric layer and a reflecting plate to expand wave absorption bandwidth, the frequency selection surface is formed by m*n cross period units, a rectangular-ring metal paster embedded in a graphene film is arranged in the center of each cross period unit, metallic branches are connected to the upper and lower sides of the rectangular-ring metal paster, and the horizontal metallic fine leads connect the single cross units in an entire row into one body. The structure is simple, and metal pasters embedded in the graphene films are used to widen the modulation bandwidth and increase the reflection wave modulation amplitude. The reflecting plate with high conductivity is used to reduce the transmission of electromagnetic waves by a wave absorption device. The artificial super-surface electromagnetic wave amplitude modulator is applicable to active electromagnetic hiding and electro-optical switch equipment.

The invention belongs to the technical field of a microwave technology and an aircraft stealth technology, and discloses a dual-band wave absorption frequency selective surface system, a design methodand an aircraft. The dual-band wave absorption frequency selective surface system is provided with a dielectric support plate, resistant thin film square rings and a circular-groove frequency selective surface, wherein the resistant thin film square rings are periodically arranged on an upper surface of the dielectric support plate, the circular-groove frequency selective surface is arranged on alower surface of the dielectric support plate and comprises a dielectric plate and a metal layer, the metal layer is arranged on an upper surface of the dielectric plate, the thickness of the metal layer is not considered, and circular grooves are periodically formed in the metal layer. By the dual-band wave absorption frequency selective surface system, k-band wave transparent/dual-band wave absorption can be achieved, an array pattern is compact, and good stability is achieved under an oblique incidence condition; the dual-band wave absorption frequency selective surface system is simple instructure; compared with a multi-layer structure, the dual-band wave absorption frequency selective surface system is only provided with the upper-layer resistant film, the intermediate-layer dielectric support plate and the lower-layer frequency selective surface, and is lighter and is lower in profile; and a transition band between the wave transparent band and the wave absorption band is small, and the wave absorption effect is good.