31results about How to "Absorbing frequency band is wide" patented technology

The invention provides a strontium titanate / polypyrrole nanocomposite fiber with a one-dimensional core-shell structure, and a preparation method thereof. The nanocomposite fiber is composed of a polymer polypyrrole body and a barium strontium titanate nanofiber material, and the barium strontium titanate nanofiber is coated with the polypyrrole to form the core-shell structure. The barium strontium titanate / polypyrrole nanocomposite fiber with the core-shell structure is prepared by an electrospinning process combined gas phase polymerization technology, and the core-shell structure of the barium strontium titanate / polypyrrole nanocomposite fiber is formed by adopting barium strontium titanate as a hard template and polyvinylpyrrolidone as a soft template in the polymerization process. The one-dimensional fibrous wave absorbing material has obvious better wave absorbing ability than a spherical wave absorbing material, the shell thickness of the composite fiber is controllable, and the material of the shell has good electrical conductivity, so the expansion of the wave absorbing band of the composite material is benefited, and the composite nanofiber has the advantages of good one-dimensional morphology, uniform size distribution, good dispersion stability, and simple and easy preparation process.

The invention belongs to the technical field of manufacturing radar stealth materials for military aircrafts and particularly relates to a broadband wave-absorbing force bearing composite material adopting a secondary curing process and a preparing method thereof. The material is composed of a wave-transparent foam layer, a wave-transparent skin layer, an electrical loss wave-absorbing layer and a shielding bottom layer. The wave-transparent foam layer is made of an on-sale closed-hole hard organic foam material with the thickness of 2 mm-20 mm; the wave-transparent skin layer is made of a continuous wave-transparent fiber enhancing resin matrix composite material with the thickness of 0.1 mm-4 mm; the electrical loss wave-absorbing layer is made of a wave-transparent fiber cloth enhancing composite material which contains carbon black and is 0.5 mm-5 mm thick; the shielding bottom layer is made of a carbon fiber woven cloth material. According to the broadband wave-absorbing force bearing composite material adopting the second curing process, the wave-absorbing frequency band is wider, electrical performance is stable, and the composite material can be applied to various military targets and used for manufacturing stealth structural members with high broadband stealth performance.

The invention discloses a wave-absorbing material for medical equipment, which is prepared by the following preparation methods: (1) preparation of a modifying agent, (2) modification of polyaniline, (3) preparation of an addition polymer, (4) ) Preparation of magnetic wave-absorbing active ingredients, (5) Surface treatment of magnetic wave-absorbing active ingredients, (6) Forming of wave-absorbing materials. The wave-absorbing material for medical devices prepared by the present invention overcomes the technical problems that the traditional wave-absorbing material has a limited wave-absorbing range and the wave-absorbing effect needs to be further improved, and has the advantages of high electromagnetic wave absorption frequency band and absorption rate, compatibility, mechanical properties and The advantage of better heat resistance.

The invention provides a resin wave-absorbing coating, which comprises: a composite material of resin, graphene and ferric oxide, a dispersant, an anti-sedimentation agent and a solvent. The present invention creatively changes the way of adding graphene materials in the resin wave-absorbing coating. Firstly, the graphene and the hard material in the coating—ferric oxide are compounded to obtain a composite of graphene and ferric oxide. The material is then combined with other ingredients to obtain resinous absorbing coatings. The invention can not only solve the problem of graphene dispersion well, ensure the perfect performance of its excellent performance, solve the disadvantage of uneven mixing of flexible graphene materials in the coating system, but also realize the The uniform dispersion on the surface can better exert its performance; more importantly, it can be used in conjunction with specific components, so that the prepared wave-absorbing coating has thin film, high strength, strong wave-absorbing ability, wide wave-absorbing frequency band, and low cost. low and has broad application prospects.

The invention relates to a wave-absorbing material with a three-layer hollow structure, a preparation method and application thereof, and belongs to the technical field of wave-absorbing materials. The three-layer hollow structure wave-absorbing material of the present invention has various loss modes such as magnetic loss, resistance loss, and dielectric loss, which makes the wave-absorbing frequency band of the particle wider and better in wave-absorbing performance. The multi-layer structure and interlayer walls in the three-layer hollow structure wave-absorbing material of the present invention improve the wave-absorbing performance of the three-layer hollow nano-particles.

The invention discloses a microwave sintering method for a SiC ceramic roller. The microwave sintering method comprises the following steps: 1) putting a green SiC ceramic roller body in an insulation apparatus and then placing the green SiC ceramic roller body and the insulation apparatus into a microwave resonant cavity together; and 2) starting a microwave source, adjusting microwave input frequency, carrying out slow heating until humidity elimination and smoke evacuation is finished, then continuously adjusting microwave input frequency, carrying out rapid heating until reflection power is stable, carrying out heating at a heating speed of 20 to 30 DEG C / min to a sintering temperature, maintaining the temperature for 5 to 15 min, then adjusting microwave input frequency and carrying out cooling to room temperature so as to obtain the SiC ceramic roller. The microwave sintering method for the SiC ceramic roller realizes rapid sintering of the SiC ceramic roller, substantially improves uniformity and stability of the performances of a sintered material, effectively avoids the phenomenon of local surface warping of a roller at a fire hole frequently occurred during conventional sintering, improves sintering yield of the SiC ceramic roller and has the advantages of short sintering time, conservation of considerable electric energy and suitability for industrial rapid production.