239results about How to "Improve microwave absorption performance" patented technology

The invention discloses a method for preparing biomass oil in a microwave thermal decomposition way, which comprises the following steps: biomass enters a screw conveyer from a storage hopper, the feeding speed of the screw conveyer is 30-60 kilogram/h; the biomass enters a microwave pyrolysis reactor through the screw conveyor, the temperature of the biomass after absorbing microwave rapidly rises to 450-550 DEG C to reach the best temperature 475-500 DEG C of the biomass producing the oil; the biomass is thermally decomposed in the microwave pyrolysis reactor to produce high-temperature organic steam, the organic steam is sent to a cyclone separating device for gas and solid separation to remove carbon grains and sand; the organic steam is discharged through the cyclone separating device, the biomass is sent to a condenser for quenching, a condensable part of the biomass is changed into the biomass oil, and the biomass oil is dropped into an oil tank, thereby the biomass oil is prepared. The invention accords with the best process requirement of the biomass oil extraction without thermal conduction and has low cost, controllable and precise thermal decomposition temperature and no thermal inertia.

The invention discloses a supported metallic oxide catalyst for assisting microwave denitration and a preparation method and a using method thereof. The catalyst is the supported catalyst using carbon as a carrier and using a metallic oxide as an active ingredient. The carrier of the catalyst is carbon-based, is convenient to obtain, large in specific surface area and capable of playing a very good dispersing role on the active ingredient of the catalyst, and the phenomenon of ingredient agglomeration is not produced. The metallic oxide is high in activity, and required supporting amount is small. The carbon-supported metallic oxide has very good microwave absorbing ability, can well play the synergistic effect of microwaves and the catalyst, the catalytic decomposition efficiency of nitrogen oxide is high, the NO decomposition rate can be above 98%, and the catalytic decomposition temperature is low and the loss of the carbon carrier is low by means of the method.

The invention discloses a preparation method of a polyaniline/sliver-coated/cobalt ferrite composite material. The preparation method comprises the following steps: respectively weighing three substances according to a stoichiometric ratio of cobalt nitrate to ferric nitrate to citric acid of 1:2:4: preparing cobalt ferrite (CoFe2O4) by adopting a sol-gel process; carrying out chemical silver-plating onto the prepared CoFe2O4 to obtain wave-absorbing filler with excellent electromagnetic performances; and preparing PANI (Polyaniline)/Ag/CoFe2O4 composite material by using aniline monomer and Ag/CoFe2O4 as raw materials through a chemical in-situ polymerization method. The composite material is combined with the excellent electrical performance of metal single substance Ag, the good magnetic performance of CoFe2O4 as well as good processability, stability and electrical performance of the conductive high polymer polyaniline, is a good microwave-absorbing material, and has an important application value in the microwave-absorbing field. The Ag/CoFe2O4 composite filler obtained by the preparation method disclosed by the invention is combined with the excellent electrical performance of the Ag and the good magnetic performance of the CoFe2O4, and is a good electromagnetic composite material; the PANI/Ag/CoFe2O4 prepared by using the composite material as the filler has good microwave-absorbing performance.

The invention discloses a preparation and an application of an Fe3O4@C@MoS2 composite material with a core-shell structure. The preparation method includes the following steps: S1. adding FeCl3 and NaOH into water, uniformly mixing, loading the mixed solution into a polytetrafluoroethylene stainless steel autoclave, and reacting to obtain uniform cubic Fe2O3 particles; S2, adding the Fe2O3 particles prepared in S1 and dopamine hydrochloride into a trimethylolaminomethane buffer solution, stirring and reacting at room temperature with a magnetic stirrer, then washing the reaction product, and collecting an Fe2O3@PDA composite with a core-shell structure through a centrifugal method; S3. adding the Fe2O3@PDA prepared in S2, ammonium molybdate tetrahydrate and thiourea into water in sequenceand stirring uniformly, washing the product after the reaction is finished, and collecting Fe2O3@PDA@MoS2 composite through the centrifugal method; and S4. calcining the Fe2O3@PDA@MoS2 composite underthe flow of hydrogen and argon to finally obtain the Fe3O4@C@MoS2 composite. The Fe3O4@C@MoS2 composite material prepared by the method has excellent microwave absorption performance.

The application relates to a multilayer hollow composite wave-absorbing material, made by mixing magnesium phenolic resin as a substrate with TiO2/SiO2/hollow nickel, zeolite powder, barite powder, carbonyl iron powder and carbon nanotubes as filling materials.

The invention discloses a solid acid catalyst suitable for a microwave-assisted reaction and a preparation method of the solid acid catalyst. The preparation method comprises the following steps: with grains or beans as a raw material, crushing, high-temperature carbonizing, concentrated sulfuric acid sulfonation, wet granulation after washing, and calcining to obtain the solid acid catalyst. The solid acid catalyst provided by the invention is simple to operate, short in period and low in cost in the whole preparation process, and is a novel solid acid catalyst which resists high temperature and is suitable for a microwave environment.

The invention described herein pertains generally to a more efficient and cost-effective method and apparatus for: (1) coupling of microwave energy from a microwave generator or plurality of microwave generators into an integral set of applicators; (2) extraction and separation of organic compounds from a mixture of organic and inorganic compounds; and (3) recovery and conversion of the organic compounds to gaseous and liquid fuels. The apparatus described in this invention result in improved microwave absorption within the mixture flowing through the applicators by increasing residence time within the applicators, resulting in a higher temperature within the material. The higher temperature lowers the viscosity of the solution, but also provides a limited reduction of the combination of complex chain and aromatic organic compounds to allow recovery of syngas and fuel oil.

Aresin matrix with strong microwave absorbability and a preparation method thereof belong to the field of composite materials. In the invention, high-performance epoxy resin with strong polarity is selected as matrix resin, a microwave absorptioncomponent is added for adjusting microwaveresponsiveness and viscosity of a resin system to adapt to liquid molding by winding and the like, a curing agent is selected for adjusting themicrowaveresponse activity of the resin system, and the mechanical property, the heat resistance and thedimensional stability of the resin matrix are achieved; on the basis, an ionic liquid modified nanometer component is adopted for further enhancing the microwaveresponsiveness of the resin matrix. By adjusting the component structure and thematch ratio of the matrix resin, the microwave absorption component, the curing agent,theionic liquid modified nanometer componentand the like, a microwave curing resin system with good microwave absorbability, good dispersity of the nanometer component, proper viscosity, uniform curing, excellent comprehensive mechanical property, good heat resistance and high dimensional stability is developed. The resin matrix has great guiding significance for preparation of fiber composite materials and can be widely applied to the fields of aerospace and the like.

The invention relates to a low-frequency stage microwave absorption material which comprises a polyurethane pyramid and a base, wherein the polyurethane pyramid is internally provided with two same inner single cones close to the base; three-layer microwave absorption sheets with same square resistance values are arranged above the inner single cones and parallel to a cone base; the square resistance values of the microwave absorption sheets range from 350 ohm to 420 ohm, the square resistance of the polyurethane pyramid ranges from 400 ohm to 600 ohm, and the square resistances of the inner single cones range from 150 ohm to 200 ohm. According to the invention, the three-layer parallel structure approximate to an electric wave in space equivalent square resistance value (377 ohm) is arranged in a polyurethane pyramid material, so that the microwave absorption property of the polyurethane pyramid wave-absorbing material between 30 MHz and 100 MHz is improved, and the absorption value ranges from -12 dB to 20 dB. The low-frequency stage microwave absorption material disclosed by the invention meets the requirement for electromagnetic compatibility and the requirement of an antenna simulation darkroom on the material.

The invention discloses a preparation method and application of a boron nitride/graphene/polyimide composite wave-absorbing and heat-conducting material. The preparation method comprises the followingsteps: weighing boron nitride powder and graphene powder, mixing, adding absolute ethyl alcohol, and carrying out ball-milling treatment; preparing a precursor of a polyimide material, adding diamineinto a polar solvent, magnetically stirring uniformly, and adding dianhydride; drying the prepared solution to obtain boron nitride/graphene composite powder, tabletting the boron nitride/graphene composite powder, and dropwise adding the prepared polyimide precursor solution after tabletting until the whole tablet is infiltrated; and heating and curing the obtained composite material twice to obtain the boron nitride/graphene/polyimide composite wave-absorbing and heat-conducting material. According to the invention, the integration of wave-absorbing and heat-transferring materials is achieved, the heat energy loss in the heating process is reduced, the heating effect is obvious, the mass volume is small, the cost is low and the mechanical property is improved. The invention provides a new method for microwave heating of non-wave-absorbing materials.

The invention belongs to the technical field of manometer function materials and particularly relates to a manganese diselenide manometer bar as well as a synthetic method and an application of the manganese diselenide manometer bar. The manganese diselenide manometer bars with different length-diameter ratios are obtained through regulating the addition quantity of surface active agents of polyvinyl pyrrolidone (PVP), and good microwave absorption performance is shown. The length-diameter ratio of the manganese diselenide manometer bar is 15 to 70, the minimum reflection loss is reduced along with the increase of the length-diameter ratio, and the minimum reflection loss can reach -12.72 dB. In addition, the preparation cost of the manometer material is low, the efficiency is high, the industrial amplification is easier for solving the practical application problem, the manometer material is used as a novel wave absorbing material to be widely applied to electromagnetic shielding andmicrowave absorption, and wide application prospects are realized.

The invention discloses a preparation method of carbon nano tube reinforcement asphalt based composite water-proof material, comprising the following steps: (1) weighing each component of the following raw materials according to weight percentages: 0.2-5% of dispersing agent, 1-5% of carbon nano tubes, 35-60% of asphalt, 9-15% of modified rubber powder and 20-40% of stuffing; (2), dissolving the dispersing agent in mixed liquor with a weight concentration of 0.1-10% prepared from asphalt, adding the carbon nano tubes in the mixed liquor, stirring by a high-speed emulsion shearing machine so as to form carbon nano tube disperse phase mixed liquor; (3) injecting the asphalt in a reaction kettle, heating till 170-190 DEG C, throwing the modified rubber powder to maintain the temperature of reaction liquid at 170-190 DEG C, modifying at a constant temperature for 1-4 hours, adding the stuffing at 150-190 DEG C for 20-80 minutes, injecting the carbon nano tube disperse phase mixed liquor obtained in the step (2), keeping a constant temperature of 140-170 DEG C, and stirring for 1-5 hours. The mechanical property of the product prepared by the invention is obviously improved, and the functions of static electricity resistance, microwave absorption, electromagnetic shielding and the like.

The invention provides a preparation method of a coaxial cable structure MWCNT/Fe3O4/ZnO/PANI microwave absorbant, and relates to a preparation method of a microwave absorbent, and the method is used for solving the problems that the wave absorption material prepared by adopting the existing method is limited into binary and ternary, and is bad in binding force with matrixes to cause poor wave absorption effect. The preparation method comprises the steps: I preparing an MWCNT/Fe3O4 nanomaterial; II preparing MWCNT/Fe3O4/ZnO composite powder; III preparing compound water solution; and IV preparing ammonium persulfate aqueous solution, then dropwise adding into the composite aqueous solution, performing constant-temperature reaction under the condition of 0-25 DEG C, then performing magnetic separation, collecting solid phase matters, and drying to obtain the coaxial cable structure MWCNT/Fe3O4/ZnO/PANI microwave absorbant, thereby completing the preparation method. The preparation method is applied in the field of microwave absorption materials.

The invention belongs to the field of electromagnetic wave absorbing materials, and particularly relates to a dodecylbenzene sulfonic acid doped PANI/MXene composite wave absorbing material and a preparation method thereof. The composite wave absorbing material is prepared by doping a polyaniline/MXene nano composite material with dodecylbenzene sulfonic acid. The method has the advantages of mildprocess conditions, low production cost, simple process and stable product quality, and is beneficial to industrial production.

The invention discloses a high-transmittance microwave absorption light window with an electrically controlled and adjustable reflection frequency band, and belongs to the field of optical transparentelectromagnetic shielding and microwave communication. The light window is formed by assembling a graphene layer, a transparent dielectric layer A, an electronic control adjustable frequency selective surface layer integrated with a phase change material, a transparent dielectric layer B and a metal mesh layer which are sequentially overlapped and arranged in parallel. The electronic control adjustable frequency selective surface layer of the integrated phase change material is composed of a frequency selective surface of the integrated phase change material, a metal electrode and a lead. Thefrequency selective surface of the integrated phase-change material is formed by periodically and closely connecting and arranging frequency selective surface array units of the integrated phase-change material, wherein the frequency selective surface array units are composed of a grid mesh aperture type frequency selective surface, a grid mesh patch type frequency selective surface and tiny phase-change material patches. The invention solves the problem that the existing microwave reflector is difficult to realize high optical transparency, adjustable reflection frequency band and out-of-band rejection of the reflection frequency band at the same time so as to mainly realize absorption.

The invention belongs to the technical field of preparation of microwave absorption materials, and particularly relates to an absorption frequency adjustable microwave absorption material and a preparation method thereof. A monolayer oriented carbon nano tube film of the microwave absorption material is composed by height oriented carbon nano tubes arrayed in the same direction, and the surface density is 1.97gm<-2>. A series of absorption frequency adjustable microwave absorption materials are acquired through change of an included angle (0-90 degrees) of two oriented carbon nano tube films. Iron and polyaniline are composited on the oriented carbon nano tubes through electron beam evaporation and electrochemical polymerization to further improve microwave absorption performance of the material. Through adjustment of the included angle of the two oriented carbon nano tube films, adjustment of microwave absorption frequency is realized; through increase of the number of the oriented carbon nano tube films or composition with the iron and the polyaniline, microwave absorption performance is improved.

The invention relates to a bimetallic cobalt-based core-shell material and a preparation method and application thereof. A core of the bimetallic cobalt-based core-shell material is a magnetic metal Co, and a shell of the bimetallic cobalt-based core-shell material is a non-magnetic metal Ag or Cu; a shape of the bimetallic cobalt-based core-shell material is fibrous or spherical, a fiber diameteris 1.3 to 36 micrometer, and a spherical diameter is 1 to 7.3 micrometer; an atomic ratio of Co to Cu is 0.25 to 21.6, and the atomic ratio of Co to Ag is 59.8 to 74.8; a saturation magnetization strength ranges from 62.2 to 159.9 emu/g<-1>. The bimetallic cobalt-based core-shell material adopts an in-situ metal replacement method and has a microwave absorption characteristic of broadband and high absorption, wherein an effective frequency band width of which the reflectivity is less than or equal to -10dB is 5.1-7.76GHz; a bandwidth less than or equal to -20dB is 2.32-16.0GHz; a maximum reflection loss ranges from -52.5 dB to -19.7 dB. The bimetallic cobalt-based core-shell material has the advantages of simple process, easy industrial popularization, excellent material performance and good application prospect in the fields of catalysis, electrode materials, microwave absorption, high-density magnetic recording materials, sensors and the like.

The present disclosure provides for methods of using adhesive compositions having improved microwave absorbing properties to bond substrates to form laminated structures. Specifically, the adhesive compositions utilized in the methods of the present disclosure absorb the microwave energy, thereby heating and melting into the substrate materials and bonding the substrates together, providing for an improved laminated structure.

The invention relates to a graphene and ferroferric oxide @gold composite, and a preparation method and an application of the graphene and ferroferric oxide @gold composite. The preparation method of the graphene and ferroferric oxide @gold composite comprises the following steps: a ferroferric oxide @gold complex modified by azide mercaptan is constructed, oxidized graphene is activated by thionyl chloride and then reacts with propargyl alcohol to produce alkynylation oxidized graphene, and then the ferroferric oxide @gold complex and the alkynylation oxidized graphene are catalyzed in a nitrogen atmosphere and alkynyl groups and and azide groups undergo click reaction, thereby obtaining the graphene and ferroferric oxide @gold composite. Reaction conditions of the preparation method of the graphene and ferroferric oxide @gold composite are mild and the preparation method is simple and reliable. The graphene and ferroferric oxide @gold composite allows a system to be stable through covalent bond connection, has the characteristics of magnetism, good microwave absorption performance, good plasma resonance absorption and attenuation to X-rays, and can be applied to nuclear magnetic imaging, microwave-induced thermoacoustic tomography, photoacoustic tomography and X-ray imaging.