22results about How to "Good electromagnetic shielding" patented technology

The invention belongs to the technical field of electromagnetic shielding materials and conductive composite fabrics, and particularly relates to an EMI shielding fabric and a preparation method thereof. Firstly, a layer of PDDA solution with positive charges is adsorbed on the surface of the fabric, then the fabric with the positive charges is soaked in ANF dispersion liquid prepared in advance, and the stable high-temperature-resistant fabric adsorbing the ANFs is prepared; the preparation method comprises the following steps: firstly, preparing a high-temperature-resistant fabric, then pretreating the high-temperature-resistant fabric through ultrasonic treatment, activating a fiber membrane through sodium borohydride solution treatment, and chemically plating nickel on the surface of the high-temperature-resistant fabric adsorbing ANFs through a palladium-free chemical plating process, so that the prepared high-temperature-resistant flexible fabric has excellent flexibility, heat resistance, corrosion resistance and efficient shielding effect; the method is easy to operate, economical and environmentally friendly, the porous structure of the formed flexible conductive high-temperature-resistant EMI shielding fabric and the nickel coating on the surface enable the material to have excellent electromagnetic shielding performance, and the problem of mutual interference between electronic elements can be solved.

The invention discloses a preparation method of light high-strength electromagnetic shielding and infrared stealth composite aerogel. The preparation method comprises the following steps: step 1, preparing a Ti3C2Tx MXene aqueous dispersion; step 2, pretreating the aramid paper honeycomb; step 3, preparing a polydopamine modified aramid paper honeycomb according to a product obtained in the step 2; step 4, preparing aramid paper honeycomb reinforced MXene-based composite hydrogel according to products obtained in the step 1 and the step 3; and step 5, freezing the aramid paper honeycomb reinforced MXene-based composite hydrogel obtained in the step 4 in liquid nitrogen, and drying to obtain the aramid paper honeycomb reinforced MXene-based composite aerogel. The invention also discloses the light high-strength electromagnetic shielding and infrared stealth composite aerogel prepared by the preparation method, and the aerogel has light weight, high strength and excellent electromagnetic shielding and infrared stealth performance, and meets the application requirements in the fields of aerospace, weaponry, electronics and electricity and the like.

This invention discloses a room-temperature self-healing electromagnetic shielding hydrogel composite material and its preparation method, belonging to the field of composite material technology. The composite material uses polyvinyl alcohol containing aryl indole groups and conductive materials as raw materials, and ferric chloride and borax as crosslinking agents. Based on the steric hindrance effect introduced by the large-volume groups and the multiple dynamic bonds constructed in the system, this invention enables the composite material to exhibit highly efficient self-healing ability, high mechanical strength, and excellent electromagnetic interference shielding performance at room temperature. Through repeated wetting and drying treatments, the electromagnetic shielding efficiency of the hydrogel can be reversibly switched between on / off states, making it suitable for applications in flexible electronics and intelligent shielding, thus solving the problem that traditional hydrogel materials struggle to simultaneously achieve self-healing performance, mechanical strength, and electromagnetic shielding effectiveness.

The utility model discloses a kind of magnetic bearing control box, it is related to magnetic levitation energy storage flywheel system technical field, to solve the problem of poor compatibility of existing control box, heat dissipation and electromagnetic shielding deficiency. It includes the main body box of detachable top cover plate, first, second function area is separately arranged in box: first function area extends along the length direction of box body, installs drive circuit board and control circuit board;Second function area is located at opposite side, same along length direction extends, installs power supply circuit board and the metal mounting plate with hole array, hole array is compatible with 8 / 16 channel signal acquisition board, and cooperation replaceable identification plate realizes multi-specification adaptation. Through linear convection air duct, layered space and high-efficiency heat dissipation of openwork structure, folding edge shielding part strengthens electromagnetic protection. The design improves compatibility, reduces control box type, optimizes heat dissipation and shielding performance, applicable to multi-power segment magnetic levitation flywheel system. It is cost-effective, and heat dissipation and shielding performance are excellent, applicable to magnetic levitation energy storage flywheel system.

According to the technical scheme, the flexible digital current transformer is characterized in that the flexible digital current transformer comprises a Rogowski coil and a transformer body, the transformer body comprises a box body composed of an upper shell and a lower shell, the two ends of the box body are correspondingly provided with communicated hole grooves, and the two ends of the Rogowski coil stretch into the hole grooves to be connected with a circuit board; one end of the Rogowski coil is provided with a connecting plug matched with the hole groove in an inserted mode, a mounting groove is formed in the position, corresponding to the hole groove, of the connecting plug, a limiting plate matched with the connecting plug in a clamped mode and a reset spring driving the limiting plate to move towards the connecting plug are slidably arranged in the mounting groove, and the limiting plate is connected with a button with one end penetrating through the box body and exposed to the outside; an abutting ring is further arranged on the outer side of the circumference of the connecting plug, and an elastic piece driving the connecting plug to be away from the hole groove is arranged between the hole groove and the abutting ring. The limiting plate arranged in a sliding mode and the button are matched with the connecting plug, one end of the Rogowski coil can be rapidly disassembled and assembled, meanwhile, the button does not need too large operation space, and disassembling and assembling are more convenient.

The application discloses an electromagnetic protection device for a car engine signal line, characterized in that the electromagnetic protection device comprises an engine signal protection circuit and a protection shell; wherein the engine signal protection circuit comprises a gas discharge tube, a transient voltage suppression diode and a filter circuit; the gas discharge tube is arranged at the front end of the engine signal protection circuit and is used for primary energy discharge; the transient voltage suppression diode is arranged at the middle section of the engine signal protection circuit and is used for fast response and voltage limiting protection; and the filter circuit is distributed at the middle section and the rear end of the engine signal protection circuit and is used for high-frequency interference suppression. The electromagnetic safety of the engine signal line can be comprehensively ensured, the reliability and stability of the vehicle control system are improved, and the maintenance cost is reduced.

The invention discloses a fireproof flame-retardant building insulation board and a preparation method thereof, and relates to the technical field of insulation boards. When the fireproof flame-retardant building insulation board is prepared, polystyrene sequentially reacts with dimethylallylamine and 3-(3-bromopropyl) thiophene to prepare modified polystyrene; the preparation method comprises the following steps: reacting pentaerythritol with boric acid to prepare a boric acid ester flame-retardant monomer; the preparation method comprises the following steps: carrying out a reaction on magnesium hydroxide and 3-chloropropyltriethoxysilane to prepare pre-modified magnesium hydroxide; carrying out a reaction on the pre-modified magnesium hydroxide, a boric acid ester flame-retardant monomer and 2-(allyloxy)-4, 6-dichloro-1, 3, 5-triazine to prepare modified magnesium hydroxide; the modified polystyrene and the modified magnesium hydroxide are mixed and then subjected to supercritical foaming, and a polystyrene board is prepared; and sequentially coating the polystyrene board with the thiophene finishing liquid and the benzoxazole finishing liquid to obtain the fireproof flame-retardant building insulation board. The fireproof flame-retardant building insulation board prepared by the invention has excellent flame-retardant, anti-aging, antibacterial and electromagnetic shielding properties.

The invention discloses a self-supporting electromagnetic shielding composite film and a preparation method thereof. The self-supporting electromagnetic shielding composite film is composed of three-dimensional fractal silver dendrites (AgFDs) and aramid nanofiber (ANFs). The preparation method comprises the following steps: carrying out suction filtration on AgFDs / ANFs mixed dispersion liquid by adopting a vacuum-assisted suction filtration technology to prepare a wet film, and then washing, drying and hot-pressing to prepare the composite film. Under the conditions that the mass fraction of AgFDs is 80-92 wt% and the total thickness is smaller than or equal to 20 microns, the conductivity of the composite film ranges from 1.5 * 10 < 4 > S / m to 2.0 * 10 < 6 > S / m, the electromagnetic shielding effectiveness can be adjusted within the range of 30-100 dB, the electromagnetic shielding effectiveness per unit thickness reaches up to 1500-6000 dB / mm, and the composite film is particularly suitable for electromagnetic shielding of flexible electronic components and circuits.

The invention belongs to the technical field of functional thin film materials, and particularly provides a metal net transparent conductive thin film with electric heating and electromagnetic shielding properties, which has excellent conductivity, electric heating property and electromagnetic shielding property and good mechanical flexibility while keeping higher visible light transmittance. Therefore, the application requirements in the fields of flexible electronic devices, transparent heaters, electromagnetic shielding devices and the like are met. The metal net transparent conductive film comprises a transparent flexible substrate, a transition layer and a metal net conductive layer, the transition layer and the metal net conductive layer are sequentially deposited on the transparent flexible substrate, the transition layer adopts Cr or Ti, and the metal net conductive layer has a random grid structure to form a continuous conductive path. In conclusion, the metal net transparent conductive film provided by the invention has multiple functions of transparent conduction, electric heating, electromagnetic shielding, high flexibility and the like, and can be applied to the fields of flexible electronic devices, transparent heaters, transparent electromagnetic shielding devices and the like.

The utility model discloses a high-thermal-conductivity silicone rubber insulation high-voltage cable for a new energy automobile, and the cable consists of a soft copper conductor, a semi-conductive wrapping layer, a silicone rubber insulation layer, a non-metal shielding layer, a metal braided shielding layer, and a sheath layer. A high-thermal-conductivity silicone rubber insulating layer and a non-metal shielding layer are uniformly extruded on the semi-conductive wrapping layer, tinned copper wires are braided outside the non-metal shielding layer to form a metal braided shielding layer, the non-metal shielding layer and the metal braided shielding layer form a composite shielding structure layer, and a high-thermal-conductivity silicone rubber sheath layer is extruded outside the metal braided shielding layer. The cable has the advantages that the cable is high in heat conduction, good in insulation resistance, soft and good in electromagnetic shielding, the rated voltage is DC 1500V and below, the heat conduction coefficient of the insulation and sheath is 3.0-3.8 W / m.K, the flame retardant property of the cable can reach V-0 (UL94), the temperature rise test of the cable is reduced by 10-20K, and the problem of temperature rise on the surface of the cable is effectively solved.

The present application relates to the technical field of polyvinyl chloride foam material preparation, and particularly relates to a polyvinyl chloride electromagnetic shielding foam material and a preparation method thereof, wherein polyvinyl chloride resin, diisooctyl phthalate, magnesium hydroxide, copper-plated Mxene, light calcium carbonate, a heat stabilizer, a light-proof agent and a lubricant are uniformly mixed according to a certain weight ratio, and then are mixed by using a high-temperature mixing machine, and then are subjected to mold pressing to obtain a PVC composite material forming sample; the PVC composite material forming sample is added into a barrel of a conical twin-screw extruder, is subjected to extrusion forming, is subjected to pre-stretching, and then is subjected to foaming treatment to obtain the polyvinyl chloride electromagnetic shielding foam material. After the pre-stretching process, the polyvinyl chloride electromagnetic shielding foam material is obtained, the cell morphology in the polyvinyl chloride electromagnetic shielding foam material has a certain orientation along the stretching direction, the cell size is large, the specific surface area of the cells is increased, and the electromagnetic shielding performance of the material is improved.

The invention belongs to the crossing field of electronic manufacturing and precision machinery, and particularly relates to a radar-based multilayer thin-wall part interconnection structure, which comprises a base, a microstrip plate and a metal cover plate, a first clearance fit surface is arranged between the metal cover plate and the base, a second clearance fit surface is arranged between the base and the microstrip plate, and the first clearance fit surface and the second clearance fit surface are both coated with soldering tin. The connecting structure is a soft soldering structure, and compared with a mechanical fastening structure, the thickness is smaller, the number of used parts is smaller, and the connecting structure is more suitable for installation in a narrow space; the surfaces of the interconnected parts are smooth and flat; the soldering tin is filled among the parts, so that good electrical conduction and electromagnetic shielding can be realized; the product is simple in structure, and high-degree automation can be easily achieved in the part machining, assembling and soft soldering processes; the antenna can be applied to design and manufacturing of radiation antennas; the method can be applied to design and manufacturing of a multi-channel microwave transmission assembly; the method can be applied to design and manufacturing of a power division network.

The present invention relates to the field of cable technology, and specifically to an astronaut extravehicular cable, comprising an outer sheath and a mica wrapping tape layer and an electromagnetic shielding layer arranged on the inner side of the outer sheath, wherein the electromagnetic shielding layer covers and fixes a plurality of cable cores, and the cable cores are composed of a conductor and an inner sheath; the electromagnetic shielding layer comprises a matrix resin, graphene oxide / carbon nanocomposite fibers and 3D‑MXene@M, wherein M is a transition metal element. The electromagnetic shielding layer in the present invention has good mechanical properties and excellent electromagnetic shielding effectiveness. The astronaut extravehicular cable prepared by the electromagnetic shielding layer can effectively resist electromagnetic radiation from outer space, maintain stable transmission of signals in the cable, and has broad application prospects in outer space exploration.

The invention discloses a preparation method of a double-layer electromagnetic shielding material for a Ka wave band and the double-layer electromagnetic shielding material, and belongs to the technical field of electromagnetic shielding materials. The invention discloses a preparation method of a double-layer electromagnetic shielding material. The preparation method comprises the following steps: providing conductive layer dispersion liquid and magnetic layer dispersion liquid; laterally freezing the conductive layer dispersion liquid to obtain a conductive layer frozen sample; the magnetic layer dispersion liquid is poured above the conductive layer frozen sample and is laterally frozen again, a double-layer frozen sample is obtained, the double-layer aerogel is obtained through sublimation drying, the double-layer aerogel comprises conductive layer aerogel and magnetic layer aerogel stacked with the conductive layer aerogel, and the magnetic layer aerogel is prepared from the conductive layer aerogel and the magnetic layer aerogel. The pore orientation of the magnetic layer aerogel is consistent with that of the conductive layer aerogel; and carrying out surface hydrophobic modification on the double-layer aerogel, then filling the double-layer aerogel with a macromolecular prepolymer, and carrying out curing treatment to obtain the double-layer electromagnetic shielding material. According to the invention, the preparation of the low-reflection and high-electromagnetic shielding effectiveness material for the Ka wave band is realized.

The utility model provides a chuck with a treated surface, which comprises a chuck body, a clamping jaw and a jaw seat, and a mirror coating is arranged on the surface of the chuck body. Mirror surface coatings are arranged on main parts exposed on the surface, so that the problems of oil stain and oil dripping do not exist on the surface, the management is easy, and the maintenance workload is small. In addition, the mirror surface plating layer has multiple functions of excellent corrosion resistance, wear resistance, brightness, high temperature resistance, oxidation resistance, electromagnetic shielding and the like for chuck parts such as the chuck body.

The invention provides an ultrafast laser processing device for an electromagnetic shielding and infrared anti-reflection curved surface microstructure. The device comprises a control system, an ultrafast laser, a light beam expanding module, a light beam reflecting module, a light beam space shaping module, a high-precision motion platform, a self-centering clamp, a curved surface window and a coaxial observation system. The control system controls the ultrafast laser to output a Gaussian beam, the Gaussian beam sequentially passes through the beam expanding module, the beam reflecting module and the beam space shaping module, then the control system controls the high-precision motion platform to focus a laser focus on the surface of the curved window under the assistance of the coaxial observation system, and the surface of the curved window is machined through contour fitting and machining path planning. And an embedded electromagnetic shielding mesh and a surface infrared anti-reflection microstructure are processed. According to the ultrafast laser processing device, high-quality, efficient and high-reliability manufacturing of the electromagnetic shielding and infrared anti-reflection curved surface microstructure can be achieved, and the electromagnetic shielding and infrared detection requirements in the fields of aerospace and the like are met.

The invention relates to the technical field of food heating, and discloses a radio frequency heating system with polar plates capable of being inserted into materials, the radio frequency heating system comprises a box body, a front door, a material box, a positive plate combination, a negative plate, a polar plate protection sleeve, a sliding table combination and a radio frequency power supply, the material box is placed on a support in the box body; polar plate protection sleeves are arranged outside the positive plate combination and the negative plate and are fixed with the sliding table combination; the sliding table combination is fixed with the side of the box; and the positive plate combination is connected with a radio frequency power supply on the outer side of the box body through a coaxial cable. The positive and negative plates are fixed on the sliding table combination, the distance between the plates and the depth of the plates inserted into the material can be dynamically changed, the impedance value of a capacitor formed between the material and the positive and negative plates in a circuit is changed, the material is heated in a composite heating mode of radio frequency heating and plate heat conduction, and the energy efficiency can be improved.

The invention discloses an electromagnetic shielding material and a preparation method and application thereof.The preparation method comprises the steps that firstly, a cotton fabric is placed in a saturated NaOH solution of bivalent copper salt to be subjected to an impregnation reaction, and a modified cotton fabric is prepared; and washing and drying the modified cotton fabric, and carbonizing to obtain the electromagnetic shielding material. The method is simple in process and reasonable in design, the electromagnetic shielding material with excellent performance can be obtained only through simple dipping and carbonization treatment, the method is suitable for industrial expanded application, and meanwhile the product has good electromagnetic shielding effectiveness based on the copper elementary substance and the carbonaceous material.

This invention discloses an electromagnetic shielding material, a composite material, a fabric, and their uses. The electromagnetic shielding material contains MXene nanorolls, which are MXene materials with a one-dimensional hollow roll structure. The excellent electromagnetic shielding performance of these MXene nanorolls is mainly due to the following reasons: First, the hollow tubular structure of the MXene nanorolls allows incident electromagnetic waves to be reflected and absorbed multiple times within the tubular structure. Second, the one-dimensional structure can improve the conductivity of the film, and the increased conductivity further promotes the electromagnetic shielding performance. The combined effect of these two aspects results in the high-performance electromagnetic shielding of the MXene nanoroll film.

The invention relates to a platinum diselenide-based electromagnetic shielding film and a preparation method thereof. The method comprises the following steps: 1, uniformly mixing platinum powder, selenium powder and potassium chloride powder according to a preset proportion, and placing the mixture at the bottom of a quartz tube with one sealed end; 2, putting the substrate slice into the quartz tube, arranging the substrate slice between the necking part and the opening part, and carrying out vacuum tube sealing on the quartz tube; 3, horizontally placing the quartz tube subjected to vacuum tube sealing in a single-temperature-zone tubular furnace, enabling the bottom of the quartz tube to directly face the center of the tubular furnace, and carrying out heating reaction to obtain platinum diselenide bulk crystals; 4, breaking the quartz tube, collecting the platinum diselenide bulk crystals, and grinding into powder; 5, platinum diselenide powder and carbon nanotubes are mixed and dispersed in deionized water to form turbid liquid, ultrasonic cleaning is carried out for multiple times, and the cleaned turbid liquid is obtained; and 6, carrying out suction filtration on the cleaned turbid liquid to form the platinum diselenide-based electromagnetic shielding film. The method is simple in process, and the prepared platinum diselenide-based electromagnetic shielding film can block 90% of electromagnetic waves.

The utility model relates to the field of display screen installation, in particular to an auxiliary device for installing a hexagonal LED display screen. Comprising a protective shell, the protective shell is connected with a first cover plate and a second cover plate, the first cover plate and the second cover plate are provided with through grooves respectively, the second cover plate is detachably connected with a limiting plate, the limiting plate is connected with a V-shaped plate, the first cover plate is detachably connected with a heat dissipation frame, the heat dissipation frame is connected with a heat exchange plate, the heat exchange plate is provided with heat dissipation holes, and the heat exchange plate is connected with a cooling box. The cooling box is connected with a heat dissipation pipe, the heat dissipation pipe is connected with the heat exchange plate, the heat dissipation frame is connected with a fan assembly, and the first cover plate is connected with a power source installation plate and a system plate. According to the utility model, the heat can be dissipated more efficiently, the heat dissipation effect is improved, and the stable operation of the display screen is ensured.

This invention relates to a polyimide composite film, comprising: a carrier layer; a sputtered copper layer laminated to the surface of the carrier layer; an electroplated copper layer laminated to the surface of the sputtered copper layer; and an electroplated tin layer laminated to the surface of the electroplated copper layer. The carrier layer is a polyimide film with a thickness of 5-30 μm, the sputtered copper layer has a thickness of 0.5-2 μm, the electroplated copper layer has a thickness of 2-5 μm, and the electroplated tin layer has a thickness of 1-5 μm. The surface roughness Rz of the electroplated copper layer is 1-3 μm. This invention also relates to a method for preparing the above-mentioned polyimide composite film.